Skocz do pozycji: 1.

Tytuł:

Phenotypic characterization of indigenous chicken population in Gwer-West, Benue State, Nigeria

Autorzy:

Rotimi, E. A.
Egahi, J. O.
Adeoye, A. A.

Powiązania:

https://bibliotekanauki.pl/articles/1182895.pdf

Data publikacji:

2016

Wydawca:

Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN

Tematy:

characterization
chicken
native
variations
morphometery

Opis:

This study was carried out to characterize native chickens of Gwer-West Local Government Area of Benue State, Nigeria, based on some phenotypic traits. A total of seven thousand and ninety-one (7091), 4624 females and 243 males, mature native chickens were randomly sampled from the study area. The study covered eleven (11) council wards (North Bank I, Wadata, Modern Market, Wala-mayo, Central South Mission, Bar, Fiidi, Agan, Clerk Mission, Mbalagh and North Bank II). The study was conducted between June and August 2012. Parameters examined include live body weight, body length, feather types, head shape, plumage colour, shank colour, beak colour, comb type ear-lobe colour and wattle colour. Majority of the chickens sampled are female (65.21%). The most predominant feather type, head shape, plumage colour, shank colour, beak colour, comb type, ear-lobe colour and wattle colour were normal (88.49%), plain (92.42%), complete brown (29.01%), white (41.19%), single (88.49%), white (79.37%) and white (68.02%) respectively. Mean live body weight of males (1.38 kg ±0.20) was significantly (p<0.05) heavier than the mean live body weight of females (1.23 kg ±0.19). Males were also superior to females in terms of body length (53.77 cm ±6.01 and 49.05 cm ±5.40 respectively). The study revealed that most of the parameters measured revealed distinctive variations, providing the basis for further characterization of native birds breeds, therefore future study can be concentrated on selection for qualitative traits of interest.

Źródło:

World Scientific News; 2016, 53, 3; 343-353
2392-2192

Pojawia się w:

World Scientific News

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:

Seasonal variation in heavy metal distribution in the sediments of selected dams in Nasarawa State, Nigeria

Autorzy:

Gav, B. L.
Aremu, M. O.
Etonihu, A. C.

Powiązania:

https://bibliotekanauki.pl/articles/1109614.pdf

Data publikacji:

2018

Wydawca:

Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN

Tematy:

Dams
Heavy metal
Seasonal variations
sediments

Opis:

The study was carried out to ascertain seasonal variation in heavy metal distribution in sediments from Dams located in Nasarawa State, Nigeria. Sediment samples were collected twice each at two different seasons for two years from May to September, 2014 and November-December, 2014 to March, 2015 for wet and dry seasons, respectively. Similarly, sediment samples were collected from May to September, 2015 and November-December, 2015 to March, 2016 for wet and dry seasons, respectively. The samples were then assessed for heavy metal properties, using atomic absorption spectrophotography (AAS). Analysis of variance (ANOVA) was then applied. The mean results of the heavy metal levels showed high values in dry seasons and low values in wet seasons in the two years of the study. Herein, the results of ANOVA revealed significant difference in the heavy metal concentrations between the seasons, dams and years. Our study also indicated that for heavy metals, the levels determined in sediments were within the WHO acceptable standards, except for Pb and Mn. These exceeded the WHO acceptable standards for drinking water. Based on these results, the dam waters are, therefore, polluted and unsuitable for human consumption, except after treatment.

Źródło:

World News of Natural Sciences; 2018, 20; 148-159
2543-5426

Pojawia się w:

World News of Natural Sciences

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:

Seasonal changes of carbohydrate content in Antarctic krill (Euphausia superba Dana)

Autorzy:

Kołakowski, Edward
Szyper-Machowska, Lidia

Powiązania:

https://bibliotekanauki.pl/articles/2053142.pdf

Data publikacji:

1989

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

Antarctic krill
carbohydrate fractions
seasonal variations

Źródło:

Polish Polar Research; 1989, 10, 2; 133-139
0138-0338
2081-8262

Pojawia się w:

Polish Polar Research

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 4.

Tytuł:

An improved model of a three phase induction motor incorporating the parameter variations

Autorzy:

Dey, A.
Tripathi, A.
Singh, B.
Dwivedi, B.
Chandra, D.

Powiązania:

https://bibliotekanauki.pl/articles/262793.pdf

Data publikacji:

2008

Wydawca:

Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie

Tematy:

mathematical modeling
transient model
parameter variations

Opis:

A great deal of work is being done on the betterment of control through simulation of the electric drives used for various high-power purposes. The authenticity of the simulated results is based on the accurate modeling of the various parts of the electric drive system. Three–phase Induction motors form an extremely important part of the modern day electric drive system and their usage is continuously on a rise owing to their inherent properties of ruggedness, minimum maintenance requirements and continually increasing efficiencies. Usually the three-phase Induction motor model used in various research works does not incorporate stator and rotor core losses, stator and rotor stray load losses and magnetizing saturation and rotor conductor skin effects. The present paper aims at developing a threephase Induction motor model taking the above losses and effects into account. The dynamic linking of the model to a thermal model considering the temperature dependent resistive elements is an added feature. The motor model described in this paper is the extension of the conventional 2-phase lumped-parameter induction motor model. The biggest advantage is that the model is user-programmable in MA TLAB environment and can be used for system level transient studies. The simulation results of the developed model, with various parameter variations taken into account and subjected to sudden changes in load, show better torque and speed performances of the motor both in steady state and dynamic conditions.

Źródło:

Electrical Power Quality and Utilisation. Journal; 2008, 14, 1; 73-78
1896-4672

Pojawia się w:

Electrical Power Quality and Utilisation. Journal

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 5.

Tytuł:

Somaclonal variation during Picea abies and P. omorika somatic embryogenesis and cryopreservation

Autorzy:

Hazubska-Przybył, Teresa
Dering, Monika

Powiązania:

https://bibliotekanauki.pl/articles/952041.pdf

Data publikacji:

2017

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

microsatellites
somaclonal variations
somatic embryogenesis
spruce

Opis:

Embryogenic cultures of plants are exposed to various stress factors both in vitro and during cryostorage. In order to safely include the plant material obtained by somatic embryogenesis in combination with cryopreservation for breeding programs, it is necessary to monitor its genetic stability. The aim of the present study was the assessment of somaclonal variation in plant material obtained from embryogenic cultures of Picea abies (L.) Karst. and P. omorika (Pančić) Purk. maintained in vitro or stored in liquid nitrogen by the pregrowth-dehydration method. The analysis of genetic conformity with using microsatellite markers was performed on cotyledonary somatic embryos (CSE), germinating somatic embryos (GSE) and somatic seedlings (SS), obtained from tissues maintained in vitro or from recovered embryogenic tissues (ETc) and CSE obtained after cryopreservation. The analysis revealed changes in the DNA of somatic embryogenesis-derived plant material of both Picea spp. They were found in plant material from 8 out of 10 tested embryogenic lines of P. abies and in 10 out of 19 embryogenic lines of P. omorika after in vitro culture. Changes were also detected in plant material obtained after cryopreservation. Somaclonal variation was observed in ETc and CSE of P. omorika and at ETv stage of P. abies. However, most of the changes were induced at the stage of somatic embryogenesis initiation. These results confirm the need for monitoring the genetic stability of plants obtained by somatic embryogenesis and after cryopreservation for both spruce species.

Źródło:

Acta Biologica Cracoviensia. Series Botanica; 2017, 59, 1
0001-5296

Pojawia się w:

Acta Biologica Cracoviensia. Series Botanica

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 6.

Tytuł:

The relationship between CA repeat polymorphism of the IGF-1 gene and the structure of motor skills in young athletes

Autorzy:

Karpowicz, Krzysztof
Krych, Katarzyna
Karpowicz, Małgorzata
Nowak, Witold
Gronek, Piotr

Powiązania:

https://bibliotekanauki.pl/articles/1038522.pdf

Data publikacji:

2018

Wydawca:

Polskie Towarzystwo Biochemiczne

Tematy:

genetic variations
motor skills
young athletes

Opis:

The map of candidate genes that can potentially affect physical fitness becomes larger every year, and they are associated with such aspects as respiratory and cardiovascular stability; body build and composition - especially muscle mass and strength; carbohydrate and lipid metabolism; response to training; and exercise intolerance.The aim of this study was to analyze the relationship between the CA repeat polymorphism of the P1 promoter of the IGF1 gene and the structure of motor skills in the two groups of Polish young athletes in 2007-2009. In this study, 350 young sportsmen representing different sports disciplines were examined (age = 15.5 ± 0.5 years), by genotyping the IGF1 gene and determining the structure of motor skills using the International Physical Fitness Test (IPFT) battery. The multiple stepwise regression was used to determine the impact of the investigated motor skills on the indicator of the overall physical fitness, measured by the total score of the International Physical Fitness Test (IPFT). The analysis showed some regularity related to the character of the IGF1 gene polymorphism. It can be concluded that the two groups of young boys athletes practicing various sports disciplines (kinds of physical exercise) displayed similar associations between CA repeat polymorphism of the P1 promoter of the IGF1 gene and the level of motor effects. Our results suggest that this polymorphism may be a genetic marker of the physical performance phenotype. We demonstrated that CA repeat polymorphism of the P1 promoter of the IGF1 gene was associated with strength predispositions in the homozygous and non-carriers groups. In the group who were heterozygous it was speed-strength aptitudes.

Źródło:

Acta Biochimica Polonica; 2018, 65, 1; 43-50
0001-527X

Pojawia się w:

Acta Biochimica Polonica

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 7.

Tytuł:

Two-dimensional stable Lavrentiev phenomenon with and without boundary conditions

Autorzy:

Caetano, A.
Sarychev, A.
Seabra, D.

Powiązania:

https://bibliotekanauki.pl/articles/970549.pdf

Data publikacji:

2005

Wydawca:

Polska Akademia Nauk. Instytut Badań Systemowych PAN

Tematy:

multidimensional calculus of variations
Lavrentiev phenomenon

Opis:

This work contains examples of regular 2D problems of the Calculus of Variations which exhibit stable Lavrentiev phenomenon, under different types of boundary conditions.

Źródło:

Control and Cybernetics; 2005, 34, 3; 689-707
0324-8569

Pojawia się w:

Control and Cybernetics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 8.

Tytuł:

Tworzenie szeregów czasowych natężenia dopływu i parametrów jakości ścieków na potrzeby symulacji pracy oczyszczalni komunalnych
Simulating the performance of municipal wastewater treatment plants: Generation of the time series of inflow rate and quality parameters of the wastewater

Autorzy:

Sobota, J.
Szetela, R.

Powiązania:

https://bibliotekanauki.pl/articles/236468.pdf

Data publikacji:

2006

Wydawca:

Polskie Zrzeszenie Inżynierów i Techników Sanitarnych

Tematy:

oczyszczalnia ścieków
natężenie dopływu
jakość ścieków
szereg czasowy
zmienność sezonowa
symulacja
water treatment plant
flow rate
wastewater characteristics
time series
diurnal variations
daily variations
seasonal variations
simulation

Opis:

Możliwość tworzenia szeregów czasowych wejść oczyszczalni komunalnych, opisujących z godzinowym krokiem wartości natężenia przepływu i stężeń zanieczyszczeń dopływających ścieków, jest istotna w zagadnieniach projektowania i eksploatacji procesów oczyszczania ścieków. W pracy przedstawiono propozycje metody tworzenia takich wejść. Jej istotą jest wyodrębnienie z surowych przebiegów czasowych odpowiednich składowych deterministycznych (uśrednionych dobowych i rocznych "szkieletów" natężenia dopływu i stężenia zanieczyszczeń) i losowych, których modele są budowane osobno, a ich połączenie daje model generatora wejść. Wykazano, że generator dobrze naśladuje charakterystyczną zmienność sezonową, dobową i godzinową wejść oczyszczalni. Pozwala to na jego zastosowanie w analizach symulacyjnych, służących optymalizacji procesów technologicznych i strategii ich sterowania. Obecnie w większości oczyszczalni brak jest odpowiednio bogatych, kilkuletnich zbiorów danych źródłowych, obejmujących charakterystykę jakości ścieków surowych, niezbędnych do opracowania odpowiedniego generatora wejść. Na potrzeby takich przypadków zaproponowano metodologię alternatywną, wykorzystującą stwierdzone zależności korelacyjne pomiędzy średnim dobowym natężeniem dopływu ścieków i średnimi dobowymi wartościami wskaźników zanieczyszczeń ścieków surowych.
The potentiality for generating the time series of the inputs for municipal wastewater treatment plants such that describe, in hourly steps, the flow rates and concentrations of pollutants in the influent wastewater stream is of importance to the design and control of wastewater treatment processes. In this paper, a method is proposed for the generation of such inputs. The method consists in separating from the raw time series appropriate deterministic (averaged daily and annual 'skeletons' of inflow rate and pollutant concentrations) and stochastic components; their models are constructed separately, and the combination of those models produces the model of the input generator. The generator well imitates the characteristic seasonal, daily and hourly variability of the inputs for the wastewater treatment plant and can therefore be applied to simulation analyses aimed at optimizing technological processes and relevant control strategies. Presently, only few wastewater treatment plants in Poland are in possession of comprehensive data sets including the characteristic of raw wastewater quality recorded for several years, which are needed when designing an input generator. With these thoughts in mind, an alternative methodology is proposed, where use is made of the correlations between the average daily rate of wastewater inflow and the average daily concentrations of the pollutants in raw wastewater.

Źródło:

Ochrona Środowiska; 2006, R. 28, nr 2, 2; 39-46
1230-6169

Pojawia się w:

Ochrona Środowiska

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 9.

Tytuł:

Monitoring of ocean current perturbations using acoustic phase variations

Autorzy:

Zieliński, A.
Butowski, M.
Kraeutner, P.

Powiązania:

https://bibliotekanauki.pl/articles/332840.pdf

Data publikacji:

2009

Wydawca:

Polskie Towarzystwo Akustyczne

Tematy:

ocean current perturbations
acoustics phase variations
hydroacoustics

Opis:

In this paper, we review an acoustic method for measuring both average ocean current speed and sound speed along an acoustic path. The method requires two or more stations on the sea floor, synchronized through a connecting underwater electric cable, that can transmit and receive an acoustic signal and The method is based on reciprocal acoustic transmissions to determine time of flight in both the forward and reverse directions. A specific implementation of this method is proposed. We also consider a novel method for monitoring ocean current perturbations through acoustic phase measurements. In simplest form, a continuous sinusoidal signal is transmitted from one station to a second station. Any variations in ocean current speed will introduce a phase shift in the received signal proportional to the time derivative of the current speed. This effect has been demonstrated through ultrasonic in-air experiments. Finally, the two methods are combined into a single system that continuously measures small-scale ocean current velocity changes.

Źródło:

Hydroacoustics; 2009, 12; 237-248
1642-1817

Pojawia się w:

Hydroacoustics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 10.

Tytuł:

Variation of the cholesterol content in breast milk during 10 days collection at early stages of lactation

Autorzy:

Kamelska, Anna
Pietrzak-Fiećko, Renata
Bryl, Krzysztof

Powiązania:

https://bibliotekanauki.pl/articles/1039741.pdf

Data publikacji:

2012

Wydawca:

Polskie Towarzystwo Biochemiczne

Tematy:

FTIR-ATR spectroscopy
human milk
cholesterol variations

Opis:

More and more research is done concerning nutritional programming. Human milk nutrients which are consumed by infants can influence their health in later life. High level of cholesterol in human milk paradoxically lowers the cholesterol concentration in blood in adults. During the course of human lactation the cholesterol concentration decreases from 31 mg/100cm3 (colostrum) to 16 mg/100 cm3 (mature milk). According to Scopesi et al., 2002, Clin Nutr 21: 379-384, cholesterol concentration in mature milk ranged from 6.5 to 18.4 mg/100 cm3. The aim of the study was to assess the variations in breast milk cholesterol content during 10 day collection at early lactation. 48 samples of human milk were analyzed. Mean age of women was 31 years. Women were collecting samples during 10 days of an early lactation stage (1-3 months after delivery). An Attenuated Total Reflectance Fourier Transformed Infrared (FTIR-ATR) method for easy and rapid determination of cholesterol in human milk was elaborated. Cholesterol content assessed by the FTIR method ranged from 3.36 to 12.98 mg/100 cm3. Results indicate that milk cholesterol concentration during 10 consecutive days of early lactation is highly variable. Cholesterol content depends on an individual. Therefore it is suggested that not only the period of lactation but also mother's diet, age, season and place of residence are important factors determining cholesterol content.

Źródło:

Acta Biochimica Polonica; 2012, 59, 2; 243-248
0001-527X

Pojawia się w:

Acta Biochimica Polonica

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 11.

Tytuł:

La interculturalidad del español: corrección y adecuación de saludos y direcciones en la evaluación de profesores nativos
The interculturality of Spanish: correctness and adequacy of greetings and addresses in the evaluation for native teachers

Autorzy:

Ainciburu, María Cecilia
Velasco, David Rodríguez

Powiązania:

https://bibliotekanauki.pl/articles/1395899.pdf

Data publikacji:

2021-07-13

Wydawca:

Uniwersytet im. Adama Mickiewicza w Poznaniu

Tematy:

greetings
addresses
interculturality
Spanish teachers
geolectal variations

Opis:

This research aims to investigate the presence in textbooks of varied material in terms of geolectal equivalents and its perception by teachers of Spanish as a foreign language. In order to examine potential differences in their approach, a pedagogical framework-based task was designed to study a corpus of 100 ELE teachers’ evaluations (50 from Colombia and 50 from Spain) and examine their consciousness and dissimilarities regarding pragmatic correctness when expressing addresses and greeting headings in electronic messages. The results show that native teachers tend to consider as correct the stimuli of peninsular Spanish or of their own variety, while those representing different geolectal variations of Spanish tend to score very low, even being considered as inter or intralinguistic error.

Źródło:

Studia Romanica Posnaniensia; 2021, 48, 2; 19-31
0137-2475
2084-4158

Pojawia się w:

Studia Romanica Posnaniensia

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 12.

Tytuł:

Workpiece temperature variations during flat peripheral grinding

Autorzy:

Smirnov, V. A.
Repko, A. V.

Powiązania:

https://bibliotekanauki.pl/articles/409773.pdf

Data publikacji:

2018

Wydawca:

STE GROUP

Tematy:

cutting force
cutting grains
flat grinding
temperature variations

Opis:

The paper presents the results of researches of temperature variations during flat peripheral grinding. It is shown that the temperature variations of the workpiece can reach 25...30% of the average values, which can lead to some thermal defects. A nonlinear two-dimensional thermophysical grinding model is suggested. It takes into account local changes in the cutting conditions: the fluctuation of the cut layer and the cutting force, the thermal impact of the cutting grains, and the presence of surface cavities in the intermittent wheel. For the numerical solution of the problem, the method of finite differences is adapted. Researches of the method stability and convergence are made, taking into account the specific nature of the problem. A high accuracy of the approximation of the boundary conditions and the nonlinear heat equation is provided. An experimental verification of the proposed thermophysical model was carried out with the use of installation for simultaneous measurement of the grinding force and temperature. It is shown that the discrepancy between the theoretical and experimental values of the grinding temperature does not exceed 5%. The proposed ther-mophysical model makes it possible to predict with high accuracy the temperature variations during grinding by the wheel periphery.

Źródło:

Management Systems in Production Engineering; 2018, 2 (26); 93-98
2299-0461

Pojawia się w:

Management Systems in Production Engineering

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 13.

Tytuł:

Ocena spójności społeczno-gospodarczej polskich województw
Social and Economic Cohesion of the Polish Regions

Autorzy:

Nowak, Paulina

Powiązania:

https://bibliotekanauki.pl/articles/595805.pdf

Data publikacji:

2018

Wydawca:

Łódzkie Towarzystwo Naukowe

Tematy:

regional variations, cohesion policy, social and economic cohesion

Opis:

Social and economic cohesion is the essence of the European Union’s activities regarding regions. The level of development in many regions is below the EU average. For this reason, investments used by the EU’s Cohesion policy to achieve more coherence in the EU at the regional level. The aim of the paper is to assess the differentials of socio-economic cohesion among Polish regions for 2010 and 2015. The chosen aspects (such as affluence, health, education, innovativeness, entrepreneurship, regional infrastructure), which characterize socio-economic development, were analysed. The taxonomic method and cluster analysis were used to accomplish the goal. The analysis is crucial to assess the disparity between Polish regions regarding the level of development in terms of the effects of the cohesion policy.
Spójność społeczno-gospodarcza stanowi istotę działań UE w odniesieniu do regionów. Poziom rozwoju wielu z nich jest poniżej średniej UE. Dlatego inwestycje realizowane z funduszy polityki spójności zmierzają do osiągnięcia większej spójności na poziomie regionalnym. Celem artykułu jest ocena zróżnicowań spójności społeczno-gospodarczej województw w latach 2010 i 2015. Do analizy przyjęto wybrane aspekty charakteryzujące rozwój społeczny i gospodarczy, takie jak zamożność, zdrowie, edukacja, innowacyjność, infrastruktura regionalna. Do realizacji celu zastosowano metodę taksonomiczną (Z. Hellwiga) oraz analizę skupień (metoda Warda). Analiza istotna jest dla oceny dystansu dzielącego województwa pod względem poziomu rozwoju w aspekcie efektów polityki spójności.

Źródło:

Studia Prawno-Ekonomiczne; 2018, 107; 321-337
0081-6841

Pojawia się w:

Studia Prawno-Ekonomiczne

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 14.

Tytuł:

Cycle-to-cycle variations of a diesel engine operating with palm biodiesel

Autorzy:

Yasin, M. H.
Mamat, R.
Abdullah, A. A.
Abdullah, N. R.
Wyszynski, M. L.

Powiązania:

https://bibliotekanauki.pl/articles/950092.pdf

Data publikacji:

2013

Wydawca:

Instytut Techniczny Wojsk Lotniczych

Tematy:

cycle-to-cycle variations
biodiesel
combustion
diesel engine

Opis:

Biodiesel is one of biodegradable and renewable fuel, which is originated from vegetable oil or animal fats. Different fuel properties of biodiesel produce different combustion characteristics which slightly differ to mineral diesel. Combustion studies on palm-biodiesel and mineral diesel were conducted using a multi-cylinder diesel engine operating at medium engine load at 2500 rpm. The engine was water cooled inline four cylinder diesel engines without exhaust gas recirculation system. Cycle-to-cycle variations of peak cylinder pressure and mean indicated pressure of the test fuels were determined for the combustion characteristics of diesel engine. In-cylinder pressure data for the 200 consecutive cycles were determined using a Kistler pressure transducer and recorded into a combustion analyser. Three different engine loads: 20%, 40% and 60% were selected in this study with a constant engine speed of 2500 rpm. The results show that at lower load, in-cylinder pressure variations for palm biodiesel were lower compared to mineral diesel. However, at medium and high loads, palm biodiesel has dominated the peak cylinder variations. Different combustion cyclic variations for mineral diesel and B100 are observed and generally influenced by psychochemical properties differences including viscosity and density of fuel.

Źródło:

Journal of KONES; 2013, 20, 3; 443-450
1231-4005
2354-0133

Pojawia się w:

Journal of KONES

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 15.

Tytuł:

Generalized Isoperimetric FVPs Via Caputo Approach

Autorzy:

Taïeb, Amele
Dahmani, Zoubir

Powiązania:

https://bibliotekanauki.pl/articles/2188101.pdf

Data publikacji:

2019

Wydawca:

Uniwersytet Jagielloński. Wydawnictwo Uniwersytetu Jagiellońskiego

Tematy:

Caputo derivative
Fractional calculus of variations
isoperimetric problems

Opis:

In this paper, we study several fractional variational problems with functionals that contain n unknown functions with their higher order Caputo derivatives and Riemann–Liouville integrals. We prove generalized fractional Euler–Lagrange equations. We also study an isoperimetric problem with multiple constraints, and we find the optimality conditions. Some examples are provided to illustrate the applications of the results.

Źródło:

Universitatis Iagellonicae Acta Mathematica; 2019, 56; 23-40
2084-3828
0083-4386

Pojawia się w:

Universitatis Iagellonicae Acta Mathematica

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 16.

Tytuł:

Adaptacja fonetyczna i graficzna anglicyzmów w rosyjskim slangu młodzieżowym

Autorzy:

Kubecka, Katarzyna

Powiązania:

https://bibliotekanauki.pl/articles/1022983.pdf

Data publikacji:

2019-09-05

Wydawca:

Uniwersytet im. Adama Mickiewicza w Poznaniu

Tematy:

youth slang
alphabet
transliteration
practical transcription
variations
russified version

Opis:

The article analyses phonetic and graphic variations of majority of English borrowings in Russian youth slang, caused by the coexistence of two different methods of recording English borrowings with the letters of Russian alphabet. The findings of the analysis prove that the dominant way of transferring English borrowings into Russian slang corresponds with the slang’s tendency to show the russified version of English pronunciation in a written form.

Źródło:

Studia Rossica Posnaniensia; 2019, 44, 2; 359-370
0081-6884

Pojawia się w:

Studia Rossica Posnaniensia

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 17.

Tytuł:

Basic physical properties of Norway spruce (Picea abies (L.) Karst.) seeds

Autorzy:

Kaliniewicz, Z.
Markowski, P.
Anders, A.
Jadwisieńczak, B.
Rawa, T.
Szczechowicz, D.

Powiązania:

https://bibliotekanauki.pl/articles/298166.pdf

Data publikacji:

2016

Wydawca:

Uniwersytet Warmińsko-Mazurski w Olsztynie

Tematy:

seed
dimension
seed mass
range of variations
correlation
separation

Opis:

The range of variations in a given separation parameter and its relationships with other attributes have to be determined for designing seed cleaning and sorting processes. In this study, those relationships were determined for five batches of Norway spruce seeds supplied by a seed extraction plant in Jedwabno. The seeds were harvested from seed stands in northern Poland. The terminal velocity, length, width, thickness and mass of every seed were determined. The results were used to calculate the geometric mean diameter, aspect ratio, sphericity index and density of the evaluated seeds. Those parameters were compared by analysis of variance and linear correlation analysis. Similarities in the average values of all physical properties were noted only between seeds harvested in the same seed zone, from tree stands occupying the same habitat type. The analyzed seeds can be effectively separated into mass fractions with the use of traditional sorting devices such as pneumatic separators, mesh sieves with longitudinal or round openings, cylindrical graders, winnowing machines and pneumatic sieves, in order to achieve more uniform seedling emergence when each seed fraction is sown separately.

Źródło:

Technical Sciences / University of Warmia and Mazury in Olsztyn; 2016, 19(2); 103-115
1505-4675
2083-4527

Pojawia się w:

Technical Sciences / University of Warmia and Mazury in Olsztyn

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 18.

Tytuł:

Extensions of the control variational method

Autorzy:

Sprekels, J.
Tiba, D.

Powiązania:

https://bibliotekanauki.pl/articles/206097.pdf

Data publikacji:

2011

Wydawca:

Polska Akademia Nauk. Instytut Badań Systemowych PAN

Tematy:

optimal control
calculus of variations
contact problems
evolution problems

Opis:

The control variational method is a development of the variational approach, based on optimal control theory. In this work, we give an application to a variational inequality arising in mechanics and involving unilateral conditions both in the domain and on the boundary, and we explore the extension of the method to time-dependent problems.

Źródło:

Control and Cybernetics; 2011, 40, 4; 1099-1108
0324-8569

Pojawia się w:

Control and Cybernetics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 19.

Tytuł:

On a variational approach to the problem of singular geological structures
O wariacyjnym podejściu do problemu osobliwych struktur geologicznych

Autorzy:

Tomecka-Suchoń, S.

Powiązania:

https://bibliotekanauki.pl/articles/394277.pdf

Data publikacji:

2017

Wydawca:

Polska Akademia Nauk. Instytut Gospodarki Surowcami Mineralnymi i Energią PAN

Tematy:

variations of functional
fault formation
rachunek wariacyjny
tworzenie uskoku

Opis:

Recognition of geological structures often requires understanding the causes of diverse kinetic phenomenon and its underlying foundations. This pertains, e.g., to the phenomenon of mass movement within a rock formation leading to fault formation. We discuss here the possibility that variational calculus may be an important tool for investigating this problem. Analysis of variations may yield important information concerning a physical phenomenon. Here we will neglect the best known problems of extremals in the analysis of variations and will focus our attention on electromagnetic and physico-mechanical problems. Adaptation of a Hamiltonian as an entropy operator may serve, not only for the problems of singular crystalline structures, but also geological singularities such as faults, oleate impermeabilities, deep-seated eruptions as well as in problems of seismology, vulcanology and earthquakes. This paper is an attempt to initiate a discussion about the possible development of the ideas presented. It might be that the formulae presented will be useful for the solution of other geophysical problems in future.
Poznanie geologicznych struktur często wymaga zrozumienia przyczyn kinetyki zjawiska przy uwzględnieniu jego zasadniczych podstaw. Takie ujęcie umożliwia nam powiązanie skutków procesów z przyczynami je warunkującymi. Dotyczy to wielu zjawisk, na przykład transportu masy wewnątrz górotworu prowadzącego do powstania uskoku. Rozważamy możliwość zastosowania rachunku wariacyjnego w rozwiązywaniu wspomnianego zagadnienia, zachęcając jednocześnie do krytycznego oglądu i własnych przemyśleń. Przy pomocy analiz wariacyjnych uzyskać możemy wiele informacji o zjawisku fizycznym. Wyłączeniu ulegną najbardziej znane problemy ekstremali, które zostaną w znacznej części pominięte, natomiast całkowicie skupimy się na zagadnieniach elektromagnetycznych i mechanicznych. Adaptacja hamiltonianu jako operatora entropijnego służyć może nie tylko problematyce osobliwych struktur krystalicznych, ale również problematyce osobliwych struktur geologicznych, takich jak uskoki, pułapki naftowe, erupcje wgłębne czy w zagadnieniach sejsmologii, wulkanologii czy trzęsień ziemi. Niniejsza praca jest próbą zachęty do dyskusji nad rozwinięciem tego zagadnienia. Trzeba też zauważyć, że rachunek wariacyjny może okazać się przydatny w rozwiązywaniu innych problemów geofizycznych, co nastąpi w nieodległej przyszłości.

Źródło:

Zeszyty Naukowe Instytutu Gospodarki Surowcami Mineralnymi i Energią PAN; 2017, 101; 335-345
2080-0819

Pojawia się w:

Zeszyty Naukowe Instytutu Gospodarki Surowcami Mineralnymi i Energią PAN

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 20.

Tytuł:

Antun Gustav Matoš’ autobiographische Märchen
Autobiographical Fables by Antun Gustav Matoš

Autorzy:

Katušić, Bernarda

Powiązania:

https://bibliotekanauki.pl/articles/635776.pdf

Data publikacji:

2014

Wydawca:

Uniwersytet im. Adama Mickiewicza w Poznaniu

Tematy:

Antun Gustav Matoš
folk tale
literary fable
variations
autobiography

Opis:

The paper aims to show that in his prose oeuvre, Matoš appropriates the typical fairy tale elements, unifies different fairy tale traditions and adapts them pursuant to the symbolist poetics in order to create his own variation of a modernist literary fable (Kunstlermärchen).

Źródło:

Poznańskie Studia Slawistyczne; 2014, 7
2084-3011

Pojawia się w:

Poznańskie Studia Slawistyczne

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 21.

Tytuł:

Variations in developmental patterns across pragmatic features

Autorzy:

Li, Qiong

Powiązania:

https://bibliotekanauki.pl/articles/780817.pdf

Data publikacji:

2016

Wydawca:

Uniwersytet im. Adama Mickiewicza w Poznaniu

Tematy:

L2 pragmatic development; variations
longitudinal perspective
non-linearity

Opis:

Drawing on the findings of longitudinal studies in uninstructed contexts over the last two decades, this synthesis explores variations in developmental patterns across second language (L2) pragmatic features. Two synthesis questions were addressed: (a) What are the variations in developmental patterns across pragmatic features?, and (b) What are the potential explanations for the variations? In response to the first question, previous studies showed that L2 pragmatic development is a non-linear, dynamic process, with developmental paces varying across pragmatic features (Ortactepe, 2013; Taguchi, 2010, 2011, 2012; Warga & Scholmberger, 2007). These studies revealed that some aspects of pragmatic features (e.g., semantic strategies of speech acts) develop faster than others (e.g., lexical features such as mitigators). In response to the second question, three potential explanations were identified to account for the developmental variations: (a) language-related, (b) situation-dependent, and (c) learner-related explanations, with three subcategories for the language-related explanation: (a) the functions of pragmatic features, (b) the frequency of availability of target features, and (c) the similarity and difference between languages with respect to the target feature.

Źródło:

Studies in Second Language Learning and Teaching; 2016, 6, 4; 587-617
2083-5205
2084-1965

Pojawia się w:

Studies in Second Language Learning and Teaching

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 22.

Tytuł:

Selected physical parameters of common hornbeam (Carpinus betulus L.) nuts

Autorzy:

Kaliniewicz, Z.
Tylek, P.
Markowski, P.
Anders, A.
Rawa, T.
Liedtke, M.

Powiązania:

https://bibliotekanauki.pl/articles/298164.pdf

Data publikacji:

2015

Wydawca:

Uniwersytet Warmińsko-Mazurski w Olsztynie

Tematy:

common hornbeam
seeds
physical parameters
range of variations
correlation
separation

Opis:

Selected physical parameters of common hornbeam nuts were determined in five batches of nuts harvested from seed tree stands in northern Poland. The results were used to calculate the arithmetic and geometric mean diameters, aspect ratio, sphericity index, volume and density of each nut. The above parameters were compared by analysis of variance, correlation analysis and linear regression analysis. Habitat conditions had a greater influence on nut plumpness than the age of the tree stand. Nut width was highly correlated with nut mass, and the above observation can be used in the process of separating nuts into mass categories. When two mesh screens with 5 mm and 6 mm openings are used, nuts will be separated into a fine-sized fraction containing 71.4% of nuts with reduced plumpness, 24.1% of moderately plump nuts and 1.8% of plump nuts, and a coarse-sized fraction containing 2.0% of nuts with reduced plumpness, 43.6% of moderately plump nuts and 54.4% of plump nuts.

Źródło:

Technical Sciences / University of Warmia and Mazury in Olsztyn; 2015, 18(4); 247-259
1505-4675
2083-4527

Pojawia się w:

Technical Sciences / University of Warmia and Mazury in Olsztyn

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 23.

Tytuł:

High-order variations and small-time local attainability

Autorzy:

Krastanov, M. I.

Powiązania:

https://bibliotekanauki.pl/articles/970758.pdf

Data publikacji:

2009

Wydawca:

Polska Akademia Nauk. Instytut Badań Systemowych PAN

Tematy:

small-time local attainability of a set
high-order control variations

Opis:

We study the problem of small-time local attainability (STLA) of a closed set. For doing this, we introduce a new concept of variations of the reachable set, well adapted to a given closed set and prove a new attainability result.

Źródło:

Control and Cybernetics; 2009, 38, 4B; 1411-1427
0324-8569

Pojawia się w:

Control and Cybernetics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 24.

Tytuł:

Territorial variation in mortality from causes amenable to medical care in Poland

Autorzy:

Wróblewska, Wiktoria

Powiązania:

https://bibliotekanauki.pl/articles/990859.pdf

Data publikacji:

2017

Wydawca:

Instytut Medycyny Wsi

Tematy:

amenable mortality
spatial variations
socioeconomic covariates
health care resources
multilevel modelling

Opis:

Introduction and objective. This study examines the geographical variation of amenable mortality in Poland, focusing primarily on the role of health care resources at the level of administrative districts and regions, and selected area socioeconomic characteristics as explanatory factors. The concept was used of amenable mortality, based on the assumption that deaths from certain causes should not occur in the presence of timely and effective health care. Materials and method. Standardized death rates (SDR) from causes considered amenable to health care and, separately, for ischaemic heart disease (IHD), were calculated for each of 379 districts (NUTS 4 level) in Poland in 1991–1995 and 2006–2010, using unit mortality data from the National Causes of Death Register. The analytical procedure involved spatial analysis of the distribution of amenable mortality rates, selection of explanatory variables and fitting multilevel regression models using area-level and regional-level characteristics. Results. The results indicate that mortality from conditions which have become amenable to medical intervention has generally decreased in all districts of Poland in the past two decades. Considerable territorial variation in mortality can be observed. Since the 1990s, these differences have been reduced for IHD-related mortality and have increased for amenable mortality. Conclusions. The presented analysis only partly confirms the correlation between variables reflecting the infrastructure of health care resources and the territorial variation in mortality from these two categories of causes of death. Significant correlations with variation in mortality are revealed for the number of primary care physicians (at district level) and the number of specialist practitioners (at regional level). However, after controlling for socioeconomic variables, such as education and low income, the effect of the health care infrastructure-related variables was considerably reduced. The multi-level models also revealed a substantial variation at the regional level, which implies that there are other unobserved contextual influences on amenable mortality at this level.

Źródło:

Annals of Agricultural and Environmental Medicine; 2017, 24, 3
1232-1966

Pojawia się w:

Annals of Agricultural and Environmental Medicine

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 25.

Tytuł:

The anatomical variations of pancreatic duct in the patients with pancreatic diseases

Autorzy:

Jagielski, Mateusz
Smoczyński, Marian
Adrych, Krystian

Powiązania:

https://bibliotekanauki.pl/articles/895785.pdf

Data publikacji:

2018-09-28

Wydawca:

Gdański Uniwersytet Medyczny

Tematy:

pancreatic duct
endoscopic retrograde pancreatography
anatomical variations
pancreas divisum
ansa pancreatica

Opis:

There are many anatomic variations of pancreatic duct and congenital anomalies of pancreas, which have been described in the literature. Most of them has no clinical significance and is used to be incidentally discovered in radiological examinations. We have demonstrated in our paper that the most frequent anatomical variations of pancreatic duct in the patients with pancreatic diseases are pancreas divisum as well as ansa pancreatica.

Źródło:

European Journal of Translational and Clinical Medicine; 2018, 1, 1; 63-66
2657-3148
2657-3156

Pojawia się w:

European Journal of Translational and Clinical Medicine

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 26.

Tytuł:

W hołdzie dla Diderota. Milan Kundera, Kubuś Fatalista i ich pan
In tribute to Diderot: Milan Kundera, Jacques the Fatalist and their Master

Autorzy:

Gawarecka, Anna

Powiązania:

https://bibliotekanauki.pl/articles/635442.pdf

Data publikacji:

2018

Wydawca:

Uniwersytet im. Adama Mickiewicza w Poznaniu

Tematy:

enlightenment novel
postmodern novel
literary fiction
poetics of variations
meta-literariness

Opis:

In his meta-literary and para-textual statements, Milan Kundera has been frequently turning to the issue of the enlightenment narrative experiments considered as the initial ones for the twentieth-century (post)modern creative strategies. Those experiments resulted from the striving for suppression of the over-prescription characterized the classicist rules, and they managed to direct attention to the literary genres which were undermined by the Enlightenment era that is in other words and above all, novel. In order to reveal this “modernity” of the eighteenth-century prose, the Czech writer in the work entitled Jacques and his master (1971) performed a “cultural translation” (variation) of the famous text by Diderot into the form of drama. Kundera was focused on the devices used by the French encyclopaedist which enabled him to expose the “evidence of trick” regarding the anti-illusion and fictitious character of literary representation of the world. He was, therefore, interested not so much in the philosophical and ideological background of Diderot’s tale dedicated to the romances of Jacques the Fatalist, but in the author’s freedom in his “play with the romance’s conventions” which even then was undergoing the process of fast schematisation.

Źródło:

Poznańskie Studia Slawistyczne; 2018, 15
2084-3011

Pojawia się w:

Poznańskie Studia Slawistyczne

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 27.

Tytuł:

Supportiveness of university physical environment on undergraduate students’ participation in leisure-time physical activity in south-west Nigeria

Autorzy:

Alayode, Ajibua
Onanuga, Omotayo Adebayo

Powiązania:

https://bibliotekanauki.pl/articles/1030974.pdf

Data publikacji:

2020

Wydawca:

Uniwersytet Szczeciński. Wydawnictwo Naukowe Uniwersytetu Szczecińskiego

Tematy:

built environment
commuting activity
meteorology
occupational activity
seasonal variations
weather conditions

Opis:

Participation in Leisure-Time Physical Activity (LTPA) has declined among university undergraduate students in Nigeria. Studies have identified the physical environment of universities as a potential cause of the decline; however, this claim has not been verified. Therefore, this study evaluates the role of the physical environment in universities in inducing student participation in LTPA. This study is necessary, as previous research has shown the involvement in LTPA helps in developing the physical, physiological, social, emotional and mental capacities of students. It is also a factor in the relief of daily stress from the heavy academic workloads of the university students. A quantitative research methodology was adopted for this study. A total sample of 2,867 students was selected from 14 public universities in South West Nigeria using a multi-stage sampling technique. It was deduced from the study that the physical environment was a determining factor for LTPA participation among university undergraduate students in South West Nigeria. In addition, it was found that the availability of facility infrastructure that encourages students roaming and safety pre-cautions on campus would enhance participation in LTPA among the university students.

Źródło:

Central European Journal of Sport Sciences and Medicine; 2020, 32, 4; 85-96
2300-9705
2353-2807

Pojawia się w:

Central European Journal of Sport Sciences and Medicine

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 28.

Tytuł:

Radial variations in wood density and their implications for above-ground biomass estimations, in a tropical high-andean forest

Autorzy:

González-Melo, A.

Powiązania:

https://bibliotekanauki.pl/articles/2078271.pdf

Data publikacji:

2021

Wydawca:

Polska Akademia Nauk. Instytut Dendrologii PAN

Tematy:

wood density
above-ground biomass
radial variations
tropical high-Andean trees

Opis:

Wood density (WD) is a central trait to explain tree functioning, and is also an important predic- tor of tree above-ground biomass (AGB). Therefore, radial trends in WD (i.e., from pith to bark) may have important implications in understanding tree life-history variations, as well as in forest biomass and carbon estimations. The occurrence of these radial trends in WD is thought to vary among forests, particularly with canopy openness and stratification. Yet, most of the studies on this topic in tropical forests have been conducted on lowland closed-canopy forests, while very little is known about the prevalence and magnitude of these trends among trees from open-canopy forests, such as high-mountain forests. I examined radial gradients in WD and explored their implications for AGB estimations. Radial wood cores were taken with increment borers from 69 trees belonging to 18 species from a high-An- dean forest. Each wood core was cut every 1-cm, and WD was measured for every 1-cm segment. Errors in AGB estimations that resulted from not considering radial trends in WD were estimated for each tree and species. Eight out of eighteen species had significant radial trends in WD. Among these species, two species showed decreases of WD towards the bark, one species showed increments of WD from pith to bark, and five species showed U-shaped gradients (i.e., high WD near the pith and bark, and relatively low WD at inter- mediate diameters). The prevalence of U-shaped radial trends in WD may be related to the relatively open and less stratified canopy of the study forest. Not taking into account radial trends in WD led in general to under-estimations of AGB (averaging −7.66 % when using mean WD, and −5.56 % for outer WD) in most of the study species, suggesting that tropical high-Andean forests may possibly store more biomass carbon than has been previously estimated. These findings are important to expand our knowledge on wood allocation patterns during tree ontogeny, and also to improve the accuracy of biomass and carbon estimations in tropical high-Andean forests

Źródło:

Dendrobiology; 2021, 86; 19-28
1641-1307

Pojawia się w:

Dendrobiology

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 29.

Tytuł:

β-Glucan-Mediated Alleviation of NaCl Stress in Ocimum basilicum L. in Relation to the Response of Antioxidant Enzymes and Assessment DNA Marker

Autorzy:

Alhasnawi, Arshad Naji

Powiązania:

https://bibliotekanauki.pl/articles/124951.pdf

Data publikacji:

2019

Wydawca:

Polskie Towarzystwo Inżynierii Ekologicznej

Tematy:

NaCl-stress
beta-glucan
antioxidants
molecular markers
DNA variations
genetic stability

Opis:

Salinity is one of the most important abiotic stresses which can negatively affect the plant metabolic processes in the world. This can impact the plant production, either for economic or sustenance benefits. The salinity stress can cause many physiological and biochemical changes in the plants. β-glucans are important polysaccharides, which are present in the cell walls of various cereal grains. They protect the plant responses and occur in plant suspensions. In this study, the researchers attempted to investigate various physiological mechanisms and determine the role of the β-glucans in the NaCl-mediated stress conditions on the Ocimum basilicum L. seedlings. For this purpose, they carried out an experiment for assessing various shoot and root parameters along with the antioxidant enzyme activities, proline levels and the ISSR markers. When the seedlings were exposed to the NaCl stress conditions, they showed a significant decrease in the growth parameters and an increase in the antioxidant and proline levels compared to the control seedlings grown under normal saline conditions. On the other hand, the β-glucantreated seeds, when grown under the saline stress conditions, showed better growth parameters as well as high antioxidant enzyme activities and proline levels, compared to the control and NaCl-treated plants. Furthermore, a PCR analysis was carried out using the ISSR-marker technology, which could help in evaluating the DNA fingerprints and genetic variations in the plants. The results indicated that the exogenous application of the β-glucans could protect the antioxidant enzyme activities and protect the plants against the salinity stresses, without affecting the DNA-markers without affecting the genetic variations and could be a better choice for use in DNA-markers.

Źródło:

Journal of Ecological Engineering; 2019, 20, 8; 90-99
2299-8993

Pojawia się w:

Journal of Ecological Engineering

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 30.

Tytuł:

Spatial and seasonal variability of sub-daily water temperature dynamics in the lowland agricultural catchment of the Wkra River

Autorzy:

Skorupa, Weronika
Łaszewski, Maksym A.

Powiązania:

https://bibliotekanauki.pl/articles/28411638.pdf

Data publikacji:

2023

Wydawca:

Instytut Technologiczno-Przyrodniczy

Tematy:

river water temperature
thermal fluctuations
Mazovia
Central Poland
hourly variations
thermal conditions

Opis:

The paper concentrates on seasonal and spatial variations of sub-daily water temperature dynamics in lowland agricultural streams. Temperature monitoring was carried out in 24 sampling sites distributed along the tributaries of the Wkra River during the hydrological year 2021. Statistical analysis of the obtained data documented the highest water temperature dynamics in the morning, from 5:00 to 9:00 CEST, while the lowest - from 14:00 to 18:00 CEST. Seasonally, greater water dynamics were noted in the winter, expressed by a coefficient of variation reaching up to 100%. Spatially, the highest dynamics occurred in sites with the lowest proportion of riparian vegetation, while the lowest dynamics was related to higher catchment area. In the winter, the minimum daily values were recorded most frequently in the morning hours, while maximum values in the afternoon. A similar pattern was observed in the summer, but with much lower dispersion of the relative frequencies. It was found that in the winter, the dominant influence on temperature dynamics was exerted in the upstream catchment area, while in the summer, a negative relationship with riparian shade was marked. The findings suggest that the presence of riparian vegetation reduces diurnal dynamics of water temperature and is simultaneously extremely important in prolonging the duration of optimum fluctuation, responsible for the proper development of poikilothermic organisms.

Źródło:

Journal of Water and Land Development; 2023, 59; 153--163
1429-7426
2083-4535

Pojawia się w:

Journal of Water and Land Development

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 31.

Tytuł:

Multi-harmonic approach to determine load dependent local flux variations in power transformer cores

Autorzy:

Riemer, B.
Hameyer, K.

Powiązania:

https://bibliotekanauki.pl/articles/141250.pdf

Data publikacji:

2015

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

flux distribution
local flux variations
multi-harmonic FEM
nonlinear FEM
power transformer

Opis:

This paper presents a methodology for the calculation of the flux distribution in power transformer cores considering nonlinear material, with reduced computational effort. The calculation is based on a weak coupled multi-harmonic approach. The methodology can be applied to 2D and 3D Finite Element models. The decrease of the computational effort for the proposed approach is >90% compared to a time-stepping method at comparable accuracy. Furthermore, the approach offers a possibility for parallelisation to reduce the overall simulation time. The speed up of the parallelised simulations is nearly linear. The methodology is applied to a single-phase and a three-phase power transformer. Exemplary, the flux distribution for a capacitive load case is determined and the differences in the flux distribution obtained by a 2D and 3D FE model are pointed out. Deviations are significant, due to the fact, that the 2D FE model underestimates the stray fluxes. It is shown, that a 3D FE model of the transformer is required, if the nonlinearity of the core material has to be taken into account.

Źródło:

Archives of Electrical Engineering; 2015, 64, 1; 129-138
1427-4221
2300-2506

Pojawia się w:

Archives of Electrical Engineering

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 32.

Tytuł:

Lagrange principle and necessary conditions

Autorzy:

Tikhomirov, V.

Powiązania:

https://bibliotekanauki.pl/articles/970737.pdf

Data publikacji:

2009

Wydawca:

Polska Akademia Nauk. Instytut Badań Systemowych PAN

Tematy:

mathematical programming
convex analysis
calculus of variations
optimal control
Lagrange multiplier rule

Opis:

Necessary conditions of extremum (from the times of Fermat and Lagrange till our times) for extremal problems where smoothness is interlaced with convexity, and some type of regularity takes place, correspond to a unique general principle, which is due to Lagrange. This report is devoted to the Lagrange principle in the theory of optimization.

Źródło:

Control and Cybernetics; 2009, 38, 4B; 1589-1605
0324-8569

Pojawia się w:

Control and Cybernetics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 33.

Tytuł:

Retrospective Analysis of Ukrainian Air Transport Activity

Autorzy:

Bugayko, Dmytro
Antonova, Anna
Shevchenko, Olga
Shevchuk, Dmytro

Powiązania:

https://bibliotekanauki.pl/articles/2056524.pdf

Data publikacji:

2022-06-07

Wydawca:

Międzynarodowa Wyższa Szkoła Logistyki i Transportu

Tematy:

Retrospective Analysis
Seasonal Variations
Air Transportations
sustainable development of the national economy

Opis:

Ukraine is an aviation state that has a full cycle of development and serial production of aircraft, commercial operation of civil aviation, training and retraining of professionals for the industry. The level of development of air transport determines not only the country's image, but also the sustainable development of its national economy. The article presents a structural analysis of the trends in the development of world aviation transport, as well as the economic development of aviation transport in Ukraine and its infrastructure. The authors pay special attention to the study of the factors of the seasonality of air transportation and their influence on the results of the operational activities of air transport in Ukraine.

Źródło:

Logistics and Transport; 2022, 53-54, 1-2; 79-98
1734-2015

Pojawia się w:

Logistics and Transport

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 34.

Tytuł:

Urban traffic detectors data mining for determination of variations in traffic volumes

Autorzy:

Bartuska, Ladislaw
Hanzl, Jiri
Lizbetin, Jan

Powiązania:

https://bibliotekanauki.pl/articles/1838325.pdf

Data publikacji:

2020

Wydawca:

Sieć Badawcza Łukasiewicz. Przemysłowy Instytut Motoryzacji

Tematy:

urban road traffic
traffic variations
road traffic data mining
classification of roads

Opis:

This paper analyses road traffic volumes in the urban environment for the purpose of traffic planning and creation of traffic models. For modelling traffic in a certain area, the initial information about transport demand and distribution in given area is required. The demand for transport is further re-distributed to the transport network and measured against the current road traffic volumes / intensity of traffic. Traffic volumes over time are characterized by various periodic and non-periodic influences (variations). By studying these variations, the tools can be specified for making the final estimate of traffic volumes for a specific time period, a specific type of road or specific vehicle category, and for improving the traffic models for a specific area. In this paper, the authors study time variations in traffic volumes using the data obtained from vehicle detectors for monitoring traffic located on roads in the city of Ceske Budejovice, the Czech Republic.

Źródło:

Archiwum Motoryzacji; 2020, 90, 4; 15-31
1234-754X
2084-476X

Pojawia się w:

Archiwum Motoryzacji

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 35.

Tytuł:

Two-dimensional Newtons problem of minimal resistance

Autorzy:

Silva, C. J.
Torres, D. F.

Powiązania:

https://bibliotekanauki.pl/articles/969988.pdf

Data publikacji:

2006

Wydawca:

Polska Akademia Nauk. Instytut Badań Systemowych PAN

Tematy:

Newton's problem of minimal resistance
dimension two
calculus of variations
optimal control

Opis:

Newton's problem of minimal resistance is one of the first problems of optimal control: it was proposed, and its solution given, by Isaac Newton in his masterful Principia Mathematica, in 1686. The problem consists of determining, in dimension three, the shape of an axis-symmetric body, with assigned radius and height, which offers minimum resistance when it is moving in a resistant medium. The problem has a very rich history and is well documented in the literature. Of course, at a first glance, one suspects that the two dimensional case should be well known. Nevertheless, we have looked into numerous references and asked at least as many experts on the problem, and we have not been able to identify a single source. Solution was always plausible to everyone who thought about the problem, and writing it down was always thought not to be worthwhile. Here we show that this is not the case: the two-dimensional problem is richer than the classical one, being, in some sense, more interesting. Novelties include: (i) while in the classical three-dimensional problem only the restricted case makes sense (without restriction on the monotonicity of admissible functions the problem does not admit a local minimum), we prove that in dimension two the unrestricted problem is also well-posed when the ratio of height versus radius of base is greater than a given quantity; (ii) while in three dimensions the (restricted) problem has a unique solution, we show that in the restricted two-dimensional problem the minimizer is not always unique - when the height of the body is less or equal than its base radius, there exists infinitely many minimizing functions.

Źródło:

Control and Cybernetics; 2006, 35, 4; 965-975
0324-8569

Pojawia się w:

Control and Cybernetics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 36.

Tytuł:

Urban Traffic Detectors Data Mining for Determination of Variations in Traffic Volumes

Autorzy:

Bartuska, Ladislaw
Hanzl, Jiří
Lizbetin, Jan

Powiązania:

https://bibliotekanauki.pl/articles/1838327.pdf

Data publikacji:

2020

Wydawca:

Sieć Badawcza Łukasiewicz. Przemysłowy Instytut Motoryzacji

Tematy:

urban road traffic
traffic variations
road traffic data mining
classification of roads

Opis:

This paper analyses road traffic volumes in the urban environment for the purpose of traffic planning and creation of traffic models. For modelling traffic in a certain area, the initial information about transport demand and distribution in given area is required. The demand for transport is further re-distributed to the transport network and measured against the current road traffic volumes / intensity of traffic. Traffic volumes over time are characterized by various periodic and non-periodic influences (variations). By studying these variations, the tools can be specified for making the final estimate of traffic volumes for a specific time period, a specific type of road or specific vehicle category, and for improving the traffic models for a specific area. In this paper, the authors study time variations in traffic volumes using the data obtained from vehicle detectors for monitoring traffic located on roads in the city of Ceske Budejovice, the Czech Republic.

Źródło:

Archiwum Motoryzacji; 2020, 90, 4; 15-31
1234-754X
2084-476X

Pojawia się w:

Archiwum Motoryzacji

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 37.

Tytuł:

Biblical Canon: Formation & Variations in Different Christian Traditions
Kanon biblijny: formacja i różnice w odmiennych tradycjach chrześcijańskich

Autorzy:

Podhajski, Maksym

Powiązania:

https://bibliotekanauki.pl/articles/950633.pdf

Data publikacji:

2017

Wydawca:

Uniwersytet w Białymstoku. Wydawnictwo Uniwersytetu w Białymstoku

Tematy:

Kanon biblijny
formacja
różnice
tradycje chrześcijańskie
biblical canon
formation
variations
christian traditions

Opis:

The Canon hasn’t been constant, but historically varied. Various approach to biblical authorship and different processes led to the fact, that nowadays we can distinguish at least three canons of the Holy Bible. The most important differences concern the Old Testament. Protestant Churches include in the canon all 39 books that belong to the Hebrew Bible. The Roman Catholic Church recognize 46 Old Testament books and the Orthodox Church following the text of the Septuagint (LXX) 50 books. These differences are related to deuterocanonical books, called by Protestant Churches Apocrypha. All Christians agree with the same number of 27 books in the New Testament. However, it is a different arrangement of books in the Roman Catholic and Protestant Churches and the Orthodox Church. The existence differences in the biblical canon remain an ecumenical problem in the Christian striving to the unity.
Kościoły i Wspólnoty chrześcijańskie posiadają odmienną liczbę kanonicznych ksiąg w Piśmie Świętym. Ażeby zrozumieć przyczyny tego podziału, należy spojrzeć, jak kanon biblijny kształtował na przestrzeni wieków, poczynając od Biblii hebrajskiej poprzez formację Starego i Nowego Testamentu Biblii chrześcijańskiej. Najważniejsze różnice dotyczą Starego Testamentu. Wspólnoty protestanckie przyjęły 39 ksiąg, które przynależą do Biblii hebrajskiej. Kościół rzymskokatolicki uznaje za kanoniczne 46 ksiąg Starego Testamentu, a Kościoły prawosławne, idąc za tekstem Septuaginty (LXX) – 50 ksiąg. Te różnice dotyczą deuterokanonicznych ksiąg, określanych przez protestantów jako apokryfy. Wszyscy chrześcijanie zgadzają się co do liczby 27 ksiąg, obecnych w Nowym Testamencie, aczkolwiek w różnej kolejności. Istniejące różnice w kanonie biblijnym pozostają jednym z ekumenicznych problemów w drodze ku jedności chrześcijan.

Źródło:

Rocznik Teologii Katolickiej; 2017, 16, 3
1644-8855

Pojawia się w:

Rocznik Teologii Katolickiej

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 38.

Tytuł:

Difference and Repetition as the Aspects of Representation in Arnold Schoenberg’s Variations for Orchestra Op. 311

Autorzy:

Sowińska-Fruhtrunk, Iwona

Powiązania:

https://bibliotekanauki.pl/articles/513916.pdf

Data publikacji:

2018

Wydawca:

Uniwersytet Jagielloński. Koło Naukowe Studentów Muzykologii UJ

Tematy:

Arnold Schoenberg
Gilles Deleuze
Variations for Orchestra Op. 31
dodecaphony
difference and repetition

Opis:

The article focuses on the issues of difference and repetition, as defined by Gilles Deleuze, and their possible application to Arnold Schoenberg’s dodecaphonic work, Variations for Orchestra Op. 31. Although Schoenberg’s reflection on these problems comes from the earlier years than Deleuze’s, the correspondence of understanding the difference and repetition between them is striking. Two other terms by Deleuze and Guattari applied to the work are becoming and refrain. Repetition and refrain are associated with the representational moment in the work (motif B-A-C-H as a quote and as a type of refrain) while difference and becoming are associated with the anti-representational moment (dodecaphonic technique, developing variation technique, etc.).

Źródło:

Kwartalnik Młodych Muzykologów UJ; 2018, 2(37) Eng; 125-169
2956-4107
2353-7094

Pojawia się w:

Kwartalnik Młodych Muzykologów UJ

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 39.

Tytuł:

Różnica i powtórzenie jako aspekty reprezentacji w Variationen für Orchester op. 31 Arnolda Schönberga1
Difference and Repetition As the Aspects of Representation in Arnold Schoenberg’s Variations for Orchestra Op. 31

Autorzy:

Sowińska-Fruhtrunk, Iwona

Powiązania:

https://bibliotekanauki.pl/articles/514126.pdf

Data publikacji:

2018

Wydawca:

Uniwersytet Jagielloński. Koło Naukowe Studentów Muzykologii UJ

Tematy:

Arnold Schoenberg
Gilles Deleuze
Variations for Orchestra Op. 31
dodecaphony
difference and repetition

Opis:

The article focuses on the issues of difference and repetition, as defined by Gilles Deleuze, and their possible application to Arnold Schoenberg’s dodecaphonic work, Variations for Orchestra Op. 31. Although Schoenberg’s reflection on these problems comes from the earlier years than Deleuze’s, the correspondence of understanding the difference and repetition between them is striking. Two other terms by Deleuze and Guattari applied to the work are becoming and refrain. Repetition and refrain are associated with the representational moment in the work (motif B-A-C-H as a quote and as a type of refrain) while difference and becoming are associated with the anti-representational moment (dodecaphonic technique, developing variation technique, etc.).

Źródło:

Kwartalnik Młodych Muzykologów UJ; 2018, 2(37); 125-158
2956-4107
2353-7094

Pojawia się w:

Kwartalnik Młodych Muzykologów UJ

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 40.

Tytuł:

Zmienność mineralizacji wód dopływających z poziomu wapienia podstawowego do wyrobisk górniczych kopalni Rudna KGHM
Mineralization variability in waters flowing from the Basal Limestone to the Rudna KGHM mining excavations

Autorzy:

Kiełczawa, B.
Chudy, A.
Ślusarczyk, S.

Powiązania:

https://bibliotekanauki.pl/articles/2075613.pdf

Data publikacji:

2017

Wydawca:

Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy

Tematy:

skład chemiczny wody
wskaźniki hydrochemiczne
kopalnia Rudna
water chemistry variations
hydrochemical indices
Rudna mine

Opis:

The article discusses the results of the work on the variability of water mineralization in the Basal Limestone, inflowing to the excavations of the KGHM Polska Miedź S.A. Rudna mine. The spatial variability of the total water mineralization and concentrations ofparticular ions (Na+, Cl-, SO2-, Ca2+ and Mg2+) were analyzed. It has been observed that the mineralization of waters from the Basal Limestone is from 12 to 256 g/dm3 with a mineralization gradient at 43.34 g/dm3/100 m. The waters are of the Na-Cl chemical type. It was found that the lowest concentrations of Na+ and Cl- characterize the southern part of the study area. Concentrations of these ions increase in the northern part of the Rudna mine, where the lowest content of sulphate ions and the highest concentrations of Ca2+ ion were observed. Based on selected, most commonly used hydrochemical indexes, an attempt was made to determine the origin of the major ions.

Źródło:

Przegląd Geologiczny; 2017, 65, 11/2; 1290--1295
0033-2151

Pojawia się w:

Przegląd Geologiczny

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 41.

Tytuł:

Location of airports - selected quantitative methods
Lokalizacja portów lotniczych - wybrane metody ilościowe

Autorzy:

Merkisz-Guranowska, A.
Bieńczak, M.
Kiciński, M.
Zmuda-Trzebiatowski, P.

Powiązania:

https://bibliotekanauki.pl/articles/361970.pdf

Data publikacji:

2016

Wydawca:

Wyższa Szkoła Logistyki

Tematy:

airport
airport location
optimalization
ranking variations
port lotniczy
lokalizacja portów lotniczych
optymalizacja
szeregowanie wariantów

Opis:

Background: The role of air transport in the economic development of a country and its regions cannot be overestimated. The decision concerning an airport's location must be in line with the expectations of all the stakeholders involved. This article deals with the issues related to the choice of sites where airports should be located. Methods: Two main quantitative approaches related to the issue of airport location are presented in this article, i.e. the question of optimizing such a choice and the issue of selecting the location from a predefined set. The former involves mathematical programming and formulating the problem as an optimization task, the latter, however, involves ranking the possible variations. Due to various methodological backgrounds, the authors present the advantages and disadvantages of both approaches and point to the one which currently has its own practical application. Results: Based on real-life examples, the authors present a multi-stage procedure, which renders it possible to solve the problem of airport location. Conclusions: Based on the overview of literature of the subject, the authors point to three types of approach to the issue of airport location which could enable further development of currently applied methods.
Wstęp: Transport lotniczy obecnie odgrywa ważną rolę, jeśli chodzi o rozwój gospodarczy zarówno kraju, jak i danego regionu. Ewentualna decyzja o jego lokalizacji powinna w maksymalnym stopniu spełniać oczekiwania interesariuszy. Niniejszy artykuł podejmuje tematykę związaną z wyborem lokalizacji portów lotniczych. Metody: W artykule przedstawiono dwa główne ilościowe nurty (podejścia) związane z problematyką lokalizacyjną portów lotniczych (PL), tj. problem optymalizacji wyboru lokalizacji PL oraz problem wyboru lokalizacji spośród z góry zdefiniowanego zbioru. Pierwszy z nich związany jest z programowaniem matematycznym i sformułowaniem problemu jako zadania optymalizacyjnego drugi natomiast zszeregowaniem wariantów Z uwagi na różne podłoże metodyczne autorzy przedstawili wady i zalety obu podejść oraz wskazali tą, która ma obecnie swoje praktyczne zastosowanie. Rezultaty: W artykule, opierając się na rzeczywistych przykładach, zaprezentowano procedurę wieloetapową pozwalającą na rozwiązywanie problemu lokalizacji portów lotniczych. Wnioski: W artykule, wskazano na bazie przeglądu literaturowego trzy koncepcje podejścia do problematyki lokalizacji PL, dzięki którym możliwe byłoby rozwinięcie obecnie stosowanych metod.

Źródło:

LogForum; 2016, 12, 3; 283-295
1734-459X

Pojawia się w:

LogForum

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 42.

Tytuł:

The importance of an Aberrant Left Hepatic Artery (ALHA), so-called Hyrtl’s artery.
Znaczenie zmienności anatomicznych lewej tętnicy wątrobowej, tzw. tętnicy Hyrtla

Autorzy:

Kozłowska, Dagmara
Mituś, Jerzy W.

Powiązania:

https://bibliotekanauki.pl/articles/527490.pdf

Data publikacji:

2020

Wydawca:

Krakowska Akademia im. Andrzeja Frycza Modrzewskiego

Tematy:

variations of hepatic artery
ALHA
Hyrtl’s artery
zmienności unaczynienia tętniczego wątroby
tętnica Hyrtla

Opis:

Knowledge of anatomical variants in hepatic vascular structures is obligatory in surgical practice. The purpose of this study is to describe anatomic variations in the Left Hepatic Artery (LHA). In ~60% of cases, LHA is a branch of the proper hepatic artery. The main anatomical variant is an Aberrant Left Hepatic Artery (ALHA) which stems from the Left Gastric Artery, also known as Hyrtl’s artery. The proper identification of ALHA is of importance in the planning and performance of all surgical procedures in the upper abdomen.
Znajomość zmienności anatomicznej struktur naczyniowych jest obowiązkowym elementem w praktyce chirurgicznej. Celem artykułu jest opisanie odmian anatomicznych lewej tętnicy wątrobowej (LHA). W ok. 60% przypadków LHA to gałąź tętnicy wątrobowej właściwej. Najczęstszą zmiennością anatomiczną jest wariant lewej tętnicy wątrobowej (ALHA) odchodzącej od lewej tętnicy żołądkowej, tzw. tętnica Hyrtla. Prawidłowa identyfikacja ALHA jest istotna w planowaniu i przeprowadzaniu wszystkich zabiegów chirurgicznych w górnym piętrze jamy brzusznej.

Źródło:

Państwo i Społeczeństwo; 2020, 2; 113-118
1643-8299
2451-0858

Pojawia się w:

Państwo i Społeczeństwo

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 43.

Tytuł:

Sketch for a portrait of Kalkbrenner and Chopin

Autorzy:

Jasińska, Danuta

Powiązania:

https://bibliotekanauki.pl/articles/780113.pdf

Data publikacji:

2010

Wydawca:

Uniwersytet im. Adama Mickiewicza w Poznaniu

Tematy:

Friedrich Kalkbrenner
Fryderyk Chopin
piano
virtuosity
style brillant
variations
piano concerto
piano playing method

Opis:

In this article, the author sketches a portrait of Kalkbrenner and Chopin against the background of musical practice during the 1830s. On the basis of sources, including Chopin’s correspondence and the opinions of his contemporaries and of Chopin scholars, an attempt is made to distinguish characteristic features of the two composers in their mutual relations. Their contacts are outlined, as well as their artistic activities, with particular emphasis on Chopin’s first concert in Paris and the role of pianistic virtuosity linked with the style brillant. Attention is drawn to the properties of the Pleyel piano which Kalkbrenner and Chopin both preferred and to the differing playing aesthetics and artistic images of the two composer-virtuosos. Chosen for the purposes of stylistic comparison are their methods of piano playing, with the accent on the schematic nature of Kalkbrenner’s “finger technique”, whilst most crucial for Chopin was to bring out the beautiful quality of the sound. In the closing remarks, it is stated that the two musicians, in their pianistic, compositional and pedagogic activities, represented the distinct antithesis of one another and two different schools. Prominent in the portrait of Kalkbrenner are distinct connections with the convention of the style brillant, whilst the portrait of Chopin, who broke through those conventions, is marked by features more profound and individualised.

Źródło:

Interdisciplinary Studies in Musicology; 2010, 9; 83-100
1734-2406

Pojawia się w:

Interdisciplinary Studies in Musicology

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 44.

Tytuł:

On the numerical minimisation of the objective function applied to spherical harmonics fitting

Autorzy:

Czyrzniak, Mateusz
Rapiński, Jacek

Powiązania:

https://bibliotekanauki.pl/articles/11025754.pdf

Data publikacji:

2023

Wydawca:

Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN

Tematy:

GNSS
phase center variations
computational performance
zmienność położenia centrum fazowego
diagnostyka
monitorowanie
wydajność obliczeniowa

Opis:

The paper presents some considerations on the performance of various objective function minimization methods in the process of GNSS antenna PCV determination. It is particulary important in the case of structural health monitoring and diagnostics. PCV are used as an additional feature to improve the GNSS positioning accuracy. The process of PCV derivation is complex and involves fitting spherical harmonics into a set of observables. The paper compares computing performance and accuracy of few methods used in the fitting process.

Źródło:

Diagnostyka; 2023, 24, 3; art. no. 2023313
1641-6414
2449-5220

Pojawia się w:

Diagnostyka

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 45.

Tytuł:

Asymptotically error - optimal shape of sampling zone for query selectivity estimation method based on discrete cosine transform
Asymptotycznie optymalny kształt strefy próbkowania w metodzie szacowania selektywności zapytań, opartej na dyskretnej transformacie kosinusowej

Autorzy:

Augustyn, D. R.

Powiązania:

https://bibliotekanauki.pl/articles/375810.pdf

Data publikacji:

2012

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

query selectivity estimation
probability density function
discrete cosine transform
calculus of variations
isoperimetric problem

Opis:

The problem of query selectivity estimation for database queries is critical for efficient query execution by database management systems. A query execution method strongly depends on early estimated size of a query result. This estimation determines a data access method used later during the query execution. The selectivity parameter is a fraction of table rows that satisfy a single-table query condition. For a selection condition of a range query where an attribute has a continuous domain, the selectivity is equivalent to a definite integral form probability density function (PDF) of attribute values distribution. For a compound selection condition based on many attributes we need a multidimensional space-efficient non-parametric estimator of multivariate PDF of attribute values distribution. A known approach based on Discrete Cosine Transform (DCT) spectrum as an representation of multidimensional PDF is considered. The energy compaction property of DCT lets omit a region of spectrum coefficients with small absolute values without significant losing an accuracy of selectivity estimation. An area of relevant spectrum coefficients is called a sampling zone. Results of experiments from previous works shows that applying the reciprocal shape of the sampling zone gives the least selectivity estimation error subject to a predetermined size of the zone. The main result of this work is a theoretical confirmation of only experimental results from previous works. The paper presents the proof of the theorem that the reciprocal shape of the sampling zone is asymptotically error-optimal. The proof is based on calculus of variations and the isoperimetric problem.
Szacowanie selektywności zapytań jest krytyczne dla efektywnej realizacji zapytań w systemach zarządzania bazami danych. Sposób realizacji zapytania zależy od wstępnego oszacowania rozmiaru danych spełniających kryteria zapytania. Takie oszacowanie pozwala wybrać metodę dostępu do danych użytą później podczas realizacji zapytania. Selektywność dla zapytań jednotablicowych to stosunek liczby wierszy spełniających kryteria zapytania do liczby wszystkich wierszy tablicy. Dla zakresowych warunków zapytania, określonych na atrybutach z ciągła dziedziną, selektywność jest całką oznaczoną z funkcji gęstości prawdopodobieństwa (PDF), określającej rozkład wartości tego atrybutu. Dla złożonych warunków zapytania, opartych na kilku atrybutach, istnieje potrzeba użycia nieparametrycznego estymatora wielowymiarowej PDF, którego reprezentacja powinna być oszczędna pod względem zajętości pamięci. Jedno ze znanych podejść do konstrukcji takiego estymatora oparte jest na dyskretnej transformacie kosinusowej (DCT) - tzn. widmie z histogramu wielowymiarowego. Własność kompakcji energii pozwala na pominięcie nieznaczących współczynników widma DCT bez istotnej utraty oszacowania selektywności. Obszar znaczących współczynników widma nazywany jest strefą próbkowania. Wyniki prac eksperymentalnych innych autorów wskazują, że dla zadanego rozmiaru reprezentacji widma, optymalną strefą próbkowania (kształtem strefy o najmniejszym błędzie oszacowania selektywności) jest tzw. strefa odwrotnie proporcjonalna. Głównym wynikiem tego opracowania jest teoretyczne potwierdzenie tych eksperymentów. Artykuł przedstawia dowód twierdzenia o asymptotycznej optymalności strefy odwrotnie proporcjonalnej dla przypadku dwuwymiarowego. Dowód opiera się na elementach rachunku wariacyjnego i zagadnieniu izoperymetrycznym.

Źródło:

Theoretical and Applied Informatics; 2012, 24, 1; 3-22
1896-5334

Pojawia się w:

Theoretical and Applied Informatics

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 46.

Tytuł:

Time variations of the gravity field over Europe obtained from GRACE data

Autorzy:

Kloch-Glowka, G.
Krynski, J.
Szelachowska, M.

Powiązania:

https://bibliotekanauki.pl/articles/225141.pdf

Data publikacji:

2012

Wydawca:

Politechnika Warszawska. Wydział Geodezji i Kartografii

Tematy:

geoid height variations
GRACE mission
geopotential models
zmiany wysokości geoidy
misja GRACE
modele geopotencjalne

Opis:

Time variations of the gravity field derived from time series of geopotential model developed from GRACE data can be interpreted in terms of geoid heights, and mass time variations with unprecedented temporal resolution. Following the results of authors previous research presented at 2nd General Assembly of the IGFS, 20-22 September 2010, Fairbanks, Alaska, the series of monthly solutions of geopotential models developed from GRACE data in JPL, filtered with the use of DKK1 filter, and GLDAS hydrological model were used in the analyses. Variations of hydrology as well as variations of geoid heights for the period August 2002 – June 2010 at the continental part of Europe and selected 14 subareas were estimated with spatial resolution of 0.5° x 0.5° . Variations in mass distribution obtained from geopotential models were compared with the respective results obtained from hydrological data. Models of geoid height changes (parameters of trend and seasonal variations) were determined for the area of Europe and for 14 subareas. To verify models of geoid height changes, over the period July 2010 - October 2010 values of geoid height changes calculated using GRACE data were compared with values based on the models developed.

Źródło:

Reports on Geodesy; 2012, z. 1/92; 175-190
0867-3179

Pojawia się w:

Reports on Geodesy

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 47.

Tytuł:

Effect of variation of operational regimes in building environment on results of its energy and exergy assessments
Wpływ zmienności funkcjonowania układów ogrzewania budynków na wyniki analizy egzergetycznej i energetycznej

Autorzy:

Voloshchuk, V.

Powiązania:

https://bibliotekanauki.pl/articles/396450.pdf

Data publikacji:

2017

Wydawca:

Uniwersytet Zielonogórski. Oficyna Wydawnicza

Tematy:

exergy-based methods
building environment
stochastic variations
reference environment
analiza egzergetyczna
ogrzewanie budynków
zmienna stochastyczna

Opis:

For further development of the dynamic exergy analysis within built environment the work proposes to take into account stochastic nature of variations of operational regimes. Using the probability theory and statistics methods, the set of parameters considered as relevant for uncertainty conditions are presented. It is shown that characteristics of buildings (insulation, window performance, heat recovery, etc.) and type of the heating system have undoubtedly a strong influence not only on the energy/exergy demand and consumption but also on the sensitivity of the energy/exergy parameters to variations of external conditions. According to the results obtained after implementations of energy efficient solutions coefficient of variation of energy/exergy-based parameters can be increased up to two times.
Jedną z podstawowych cech układów ogrzewania budynków jest ich zmienność działania. Przemiany w procesie ogrzewania budynku uwarunkowane są głównie czynnikami klimatyczno-pogodowymi (temperatura, promieniowanie słoneczne, prędkość wiatru, ciśnienie, wilgotność, itp), i są o charakterze losowym. Egzergetyczne cechy takich systemów w dużej mierze zależą od zmian parametrów środowiskowych. W celu dalszego rozwoju dynamicznej analizy egzergetycznej systemów ogrzewania budynków w pracy naukowej uwzględniony został stochastyczny charakter zmienności ich działania. Biorąc pod uwagę teorię prawdopodobieństwa i metody statystyki matematycznej, zostały zaproponowane kryteria, które uwzględniają te zmienności. W przypadku zależności nieliniowej pomiędzy argumentami i funkcjami, co jest charakterystycznym dla wskaźników egzergetycznych, uśrednienie wartości funkcji, a nie funkcji średnich wartości argumentów powinno być wykorzystywane do analizy. Uwarunkowano, że charakterystyka budynków (typ konstrukcji, system odzyskiwania energii, itp.) i typ systemu grzewczego wpływają nie tylko na potrzeby energii i egzergii, ale również na ich wrażliwość na zmiany warunków zewnętrznych. Z badania wynika, że po wdrożeniu rozwiązań energooszczędnych zmienność parametrów egzergetycznych oraz energetycznych może być zwiększona dwukrotnie. W pracy zaprezentowano wyniki stosowania dynamicznej analizy do oceny egzergonomicznej.

Źródło:

Civil and Environmental Engineering Reports; 2017, No. 24(1); 147-160
2080-5187
2450-8594

Pojawia się w:

Civil and Environmental Engineering Reports

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 48.

Tytuł:

Wybrane wskaźniki jakości sterowania i ich wpływ na średnie podciśnienie w rurociągu mlecznym i jego amplitudę wahań w dojarce rurociągowej
Selected indexes of control indexes and their influence on average negative pressure in a milk pipeline and its amplitude of variations in a pipeline milking unit

Autorzy:

Skalska, D.

Powiązania:

https://bibliotekanauki.pl/articles/289150.pdf

Data publikacji:

2011

Wydawca:

Polskie Towarzystwo Inżynierii Rolniczej

Tematy:

rurociąg mleczny
zakłócenie
kryterium całkowe
wahanie podciśnienia
milk pipeline
interference
integral criterion
negative pressure variations

Opis:

Analizowano wpływ sygnałów testowych opisanych wskaźnikami jakości sterowania; maksymalnym spadkiem podciśnienia Pmax, polem powierzchni S1 (Sc) pod krzywą zmian podciśnienia w czasie trwania zakłócenia na zmiany wahań podciśnienia w rurociągu mlecznym aP14 i na zmiany średniego podciśnienia P14 w rurociągu mlecznym w pierwszym cyklu pulsacji, w trzech następnych cyklach pulsacji po wprowadzeniu zakłócenia. Pomiary wykonano dla określonej liczby równocześnie pracujących aparatów udojowych (od 1 do 6). Wykazano, że P14 w rurociągu mlecznym oraz aP14 istotnie zależą (liniowo) od zmian pola powierzchni S1 (Sc) pod krzywą opisującą ww. zakłócenia w pierwszym cyklu pulsacji (dla fazy 1 po) i w następnych trzech cyklach (dla fazy 2-4 po) po wprowadzeniu powietrza do instalacji dojarki rurociągowej.
Influence of test signals described by the quality control indexes was analysed: maximum decrease of the negative pressure Pmax, surface area S1 (Sc) beneath the curve of the negative pressure fluctuations during interference on negative pressure variation fluctuations in a milk pipeline aP14 and on the changes of average negative pressure P14 in a milk pipeline in the first cycle of pulsation, in three subsequent cycles of pulsation after introducing interference. The measures were taken for a particular number of milking units working simultaneously (from 1 to 6). It was proved that P14 in a milk pipeline and aP14 considerably depend (linearly) on the changes of surface area S1 (Sc) beneath the curve describing the abovementioned interferences in the first cycle of pulsation (for 1 po phase) and in the subsequent three cycles (for 2-4 po phase) after introducing air to a milking pipeline unit.

Źródło:

Inżynieria Rolnicza; 2011, R. 15, nr 8, 8; 245-252
1429-7264

Pojawia się w:

Inżynieria Rolnicza

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 49.

Tytuł:

Forma gatunkowa ody w łacińskiej poezji Jana Kochanowskiego (Lyricorum libellus)

Autorzy:

Buszewicz, Elwira

Powiązania:

https://bibliotekanauki.pl/articles/636389.pdf

Data publikacji:

2014

Wydawca:

Uniwersytet Jagielloński. Wydawnictwo Uniwersytetu Jagiellońskiego

Tematy:

neo-Latin poetry, works of Jan Kochanowski, Horatian imitation, poetic genres, ode and its variations

Opis:

The ode as a genre in the Latin poetry of Jan Kochanowski (Lyricorum libellus)The aim of this study is to establish the place of Jan Kochanowski’s Lyricorum libellus (1580) in the history of Polish Renaissance Neo-Latin ode presented against a wider European background. The development of this genre in this historico-literary period in Poland has received only fragmentary reporting, e.g. in relation to Horatianism in literature or as a background for the vernacular ode. Yet, as Carol Maddison argues in her Apollo and the Nine, the Neo-Latin ode is, in a sense, a new genre revived and newly “devised” by Renaissance humanists. In her fundamental work, Maddison also presents the development of the ode and its variations in Italy and France. According to ancient patterns used by poets, Horatian odes (including Kochanowski’s odes) can be divided into the “pindaric” and the “anacreontic-sapphic.” To some extent this division coincides with the classification of odes as “political” or “private.” Similar categorisation criteria adopted by various researchers (Zofia Głombiowska, Jacqueline Glomski, Józef Budzyński) may result in individual odes being assigned to several different categories. The first part of the paper, therefore, emphasises the identity of the Neo-Latin ode and its status as a new genre strongly related to Renaissance Humanism. In the second part, the author attempts to assign particular poems from Lyricorum libellus to patterns indicated by Maddison, and deals with previous attempts at classification based on differentiating between political and private odes. She also underlines that Kochanowski frequently imitated both pindaric and anacreontic patterns through Horace. In the third part, the author analyses the strophic organisation of individual odes and their metre as well as their logical-rhetorical structure. The odes are here classified with regard to these criteria and interpreted in accordance with their historical context. The author pays close attention to the genre’s borderline between ode and hymn, stylistic “nobilitation” of lyrical poems and the outright Horationism of the collection. Lastly, she presents conclusions concerning the role of Lyricorum libellus in the development of the ode. Before Kochanowski, a significant role in the evolution of the genre was played by the so-called “university ode,” which was popular in Silesian and German poetic circles, as well as in odes by Paweł z Krosna. Kochanowski’s odes, however, bear little resemblance to this stage of the development of the genre in Poland. Imitating Horace in the spirit of such poets as Michal Marullus or Giovanni Pontano, Kochanowski demonstrates a mature awareness of the Neo-Latin ode, formed at the meeting-point of ode and hymn and constituting an element of a cycle organised in accordance with a certain idea.

Źródło:

Terminus; 2014, 16, 1(30)
2084-3844

Pojawia się w:

Terminus

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 50.

Tytuł:

On the estimation of physical height changes using GRACE satellite mission data – A case study of Central Europe

Autorzy:

Godah, W.
Szelachowska, M.
Krynski, J.

Powiązania:

https://bibliotekanauki.pl/articles/145591.pdf

Data publikacji:

2017

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

satelita GRACE
pole grawitacji
przemieszczenia pionowe
GRACE
height anomaly variations
vertical displacements
physical height changes

Opis:

The dedicated gravity satellite missions, in particular the GRACE (Gravity Recovery and Climate Experiment) mission launched in 2002, provide unique data for studying temporal variations of mass distribution in the Earth’s system, and thereby, the geometry and the gravity fi eld changes of the Earth. The main objective of this contribution is to estimate physical height (e.g. the orthometric/normal height) changes over Central Europe using GRACE satellite mission data as well as to analyse them and model over the selected study area. Physical height changes were estimated from temporal variations of height anomalies and vertical displacements of the Earth surface being determined over the investigated area. The release 5 (RL05) GRACE-based global geopotential models as well as load Love numbers from the Preliminary Reference Earth Model (PREM) were used as input data. Analysis of the estimated physical height changes and their modelling were performed using two methods: the seasonal decomposition method and the PCA/ EOF (Principal Component Analysis/Empirical Orthogonal Function) method and the differences obtained were discussed. The main fi ndings reveal that physical height changes over the selected study area reach up to 22.8 mm. The obtained physical height changes can be modelled with an accuracy of 1.4 mm using the seasonal decomposition method.

Źródło:

Geodesy and Cartography; 2017, 66, 2; 211-226
2080-6736
2300-2581

Pojawia się w:

Geodesy and Cartography

Dostawca treści:

Biblioteka Nauki

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