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Tytuł:
Effects of Doping on the Structural Distortion of $La_{0.7}Dy_{0.3}Mn_{1-x}Zn_xO_3$
Autorzy:
López, J.
Ríos, M.
Mendoza, G.
Powiązania:
https://bibliotekanauki.pl/articles/1398317.pdf
Data publikacji:
2017-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.47.Lx
61.50.-f
Opis:
Structural properties were studied in the orthorhombic perovskite $La_{0.7}Dy_{0.3}Mn_{1-x}Zn_{x}O_3$, synthesized in the range 0 ≤ x ≤ 0.4. X-ray diffraction data, refined by the Rietveld analysis, shows for x < 0.1 the presence of stretched octahedra on the Mn-O plane, and, for x > 0.1, the existence of elongated octahedra along the c axis. Increased Zn doping causes a direct structural effect: one Zn atom distorts four neighboring MnO₆ octahedra on the Mn-O plane. It was observed that the unit cell volume containing Dy decreases as x increases, whereas the unit cell volume containing La increases as x decreases.
Źródło:
Acta Physica Polonica A; 2017, 131, 5; 1254-1255
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Road and street smart lighting control systems as a new application area of the hot-potato protocol
Autorzy:
Kiedrowski, P.
Boniewicz, P.
Lopez, J. G.
Prado, R. P.
Powiązania:
https://bibliotekanauki.pl/articles/97614.pdf
Data publikacji:
2014
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
smart lighting
smart grid
lighting control network
road lighting
street lighting
PLC
WSN
Opis:
This paper presents the new application area of the hot-potato routing protocol, which is a “last-mile” communication network for controlling systems of road and street lighting. Four variants of the hot-potato protocol are analyzed with use of the graph theory. For the assessment of the traffic parameters the ETX parameter is used in relation to the length of the shortest path. Proposed methods are independent of the media type and can be implemented either in wireless or PLC.
Źródło:
Computer Applications in Electrical Engineering; 2014, 12; 521-530
1508-4248
Pojawia się w:
Computer Applications in Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Distributed Decision-Support System for Virtual Prototyping
Autorzy:
Tirpak, T. M.
Lach, L. E.
Xiao, W.
Lopez, J. M.
Powiązania:
https://bibliotekanauki.pl/articles/375959.pdf
Data publikacji:
2007
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
Distributed Decision-Support
virtual prototyping
CAE
Opis:
Virtual Prototyping (VP) is a data-driven design process that promotes both knowledge reuse and innovation. High-profile applications in the automotive and aerospace industries have demonstrated its potential to significantly reduce prototype cycles, time to market, and total product cost. This paper addresses VP as a specialized application of Decision-Support Systems, and discusses common requirements for engineering design tools, as well as requirements specific to the design of electronic products, such as mobile phones. Motorola Labs' test bed for VP is introduced in terms of its open, agent-based architecture utilizing Java CORBA. One of the key principles of the VP System is the reuse of expert knowledge across multiple engineering domains. This is highlighted via several use cases, showing that the system can function not only as an Intranet-accessible repository of model services but also as an integral part of decision-making within the native CAD environment.
Źródło:
Decision Making in Manufacturing and Services; 2007, 1, 1-2; 137-152
1896-8325
2300-7087
Pojawia się w:
Decision Making in Manufacturing and Services
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Topological Correlations in a Layer Adsorbed on a Crystal Surface
Autorzy:
Wojtczak, L
Zasada, I
Bosse Le, J. C
Lopez, J
Rousseau, J
Powiązania:
https://bibliotekanauki.pl/articles/896312.pdf
Data publikacji:
1990
Wydawca:
Uniwersytet Łódzki. Wydawnictwo Uniwersytetu Łódzkiego
Opis:
The incoherent scattering of electrons by a layer adsorbed at a single crystal surface is determined by the topological correlations of elements forming the adsorbed layer. The model for the description of atoms or molecules adsorbed on the surface is formulated in terms of occupation operators which are expressed in terms of pseudospin operators with a given spin value. The correlations can be determined by the fluctuation dissipation theorem in connection with the susceptibility or given directly by means of the Green functions properly chosen. An example of the topological or chemical disorder of two components is considered in detail. The calculations of the topological correlations allow us to find the incoherent scattering amplitude as a function of the surface coverage which can be experimentally detected.
Źródło:
Acta Physicae Superficierum; 1990, 1
0867-2997
Pojawia się w:
Acta Physicae Superficierum
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Caracterisation de l'ordre par diffraction d'electrons
Autorzy:
Le Bosse, J. C.
Lopez, J.
Hansali, G.
Wiatrowski, G.
Rousseau, J.
Powiązania:
https://bibliotekanauki.pl/articles/1929266.pdf
Data publikacji:
1993-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.14.Dc
68.10.Jy
Opis:
CHARACTERIZATION OF THE ORDER BY ELECTRON DIFFRACTION: In the case of a solid with a local atomic order, we can consider only a statistical description of atomic positions. For a homogeneous phase, this description is given by the two-site occupancy correlation function, the three-site occupancy correlation function, ... etc. The local atomic order is investigated by experiments in which the solid is bombarded with a well-collimated monoenergetic beam of particles (here electrons). Starting from a model describing the force law between an electron and an atomic scatterer and from a model of the solid describing the distribution of atoms in space, a computation of elastically backscattered intensities can be carried out. The latter depends on geometrical parameters which are determined in such a way that one gets the best agreement between the results of calculation and the measurements. This work aims to provide the way of proceeding to calculate the diffuse intensity. The main difficulty in this task appears when we undertake to treat the problem of multiple scattering. We provide here a detailed description of a calculation corresponding to the case of the backscattering of electrons at a single crystal surface covered with a partially disordered atomic layer. Assuming that the coverage in adatoms is small and these adatoms are weak scatterers, we can neglect the multiple scattering events inside the layer. This simplifying assumption leads to an expression of the diffuse intensity in terms of: the Fourier transform on the 2D surface lattice of the pair correlation function; the renormalized transition matrices of the different kinds of adatoms.
Źródło:
Acta Physica Polonica A; 1993, 83, 5; 567-580
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Two-Site Correlations in a Surface Layer Adsorbed on the Crystal
Autorzy:
Wojtczak, L.
Zasada, I.
Le Bossé, J. C.
Lopez, J.
Rousseau, J.
Powiązania:
https://bibliotekanauki.pl/articles/1891742.pdf
Data publikacji:
1991-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.35.-p
Opis:
The incohorent scattering of electrons by layer adsorbed at a single crystal surface is determined by the Fourier transform of correlation functions of elements forming this layer. The model of the description of atoms or molecules adsorbed on the surface is formulated by the occupation operators which are represented by the pseudospin operators. The calculations of the correlation functions are performed by means of methods which consider a given pair of elements embedded in the effective field of remaining elements of the system while the interaction between the elements of the pair are taken in its exact form. Two approaches are presented here, i.e. the cumulant average and constant coupling approximations, and the case of binary chemisorption is considered in detail. The problem of the correlation symmetry is also discussed.
Źródło:
Acta Physica Polonica A; 1991, 80, 5; 631-648
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Antioxidant activity and cytotoxic effect of Chilean Buddleja globosa (matico) and Ribes magellanicum (zarzaparrilla) flower extracts
Autorzy:
Zamorano-Aguilar, P.
Morales, M.
Rivillas, Y.
López, J.
Rojano, B.A.
Powiązania:
https://bibliotekanauki.pl/articles/12989165.pdf
Data publikacji:
2020
Wydawca:
Uniwersytet Przyrodniczy w Lublinie. Wydawnictwo Uniwersytetu Przyrodniczego w Lublinie
Źródło:
Acta Scientiarum Polonorum. Hortorum Cultus; 2020, 19, 6; 59-70
1644-0692
Pojawia się w:
Acta Scientiarum Polonorum. Hortorum Cultus
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Monte Carlo Simulation of Partially Ordered Atomic Layers Adsorbed on the Monocristalline Surfaces
Autorzy:
Wiatrowski, G.
Le Bossé, J. C.
Lopez, J.
Rousseau, J.
Zasada, I.
Powiązania:
https://bibliotekanauki.pl/articles/1929295.pdf
Data publikacji:
1993-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.35.-p
Opis:
The calculations of the correlations functions and structure factors are performed by means of the Monte Carlo simulation. The results for O/Ni(001) system are presented and compared with those obtained using self-consistent molecular field approximation and cumulant expansion method. The simulation for more complex system CO/Pt(111) is also performed. The calculations of the topological correlations allow us to find the coverage dependence of the incoherent scattering amplitude which can be experimentally detected.
Źródło:
Acta Physica Polonica A; 1993, 83, 5; 587-596
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measurement of biological diversity of arthropods and respiration in soils managed under time-controlled and set-stocked grazing practices in central-west New South Wales, Australia
Badania różnorodności biologicznej stawonogów i oddychanie w glebach o odmiennych systemach wypasania w centralno-zachodniej Nowej Południowej Walii, Australia
Autorzy:
Moulin, M.
Lopez, J.
Raman, A.
Hodgkins, D.
Adams, A.
Mannix, S.
Powiązania:
https://bibliotekanauki.pl/articles/906653.pdf
Data publikacji:
2012
Wydawca:
Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej
Opis:
In this study we compare the effects of two contrasting grazing regimes (time-controlled grazing (TCG) vs set-stocked grazing (SSG)) on selected parameters of soil biological health. The purpose of the study was to evaluate these soil parameters as potential indicators of soil health and thence sustainable soil management. Two parameters, viz., arthropod biological diversity and soil respiration were chosen as reliable indicators of soil health. Samples of pasture cover, arthropod populations, and soil from varied depths were obtained in spring (September-November 2010) and autumn (March-May 2011). Results from the autumn showed a strong effect of time-controlled grazing with increased arthropod abundance and enhanced soil biological respiration while in spring the differences were not significant. It was concluded that a change to short-duration rotational grazing can be beneficial to soil biological health in the longer term and that the measurement of arthropods present in the litter and topsoil can be a simple yet effective indicator of the impact of grazing regime on soil health.
Źródło:
Polish Journal of Soil Science; 2012, 45, 1
0079-2985
Pojawia się w:
Polish Journal of Soil Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Apport des techniques EXAFS et apparentées a la determination de lordre local: application a la tribologie
Autorzy:
Lopez, J.
Le Bossé, J. C.
Hansali, G.
Belin, M.
Martin, J. M.
Powiązania:
https://bibliotekanauki.pl/articles/1929260.pdf
Data publikacji:
1993-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.10.Lx
Opis:
CONTRIBUTION OF EXAFS-LIKE TECHNIQUES TO THE DETERMINATION OF LOCAL ORDER: APPLICATION TO TRIBOLOGY: The determination of local order at atomic scale becomes more and more fundamental for understanding superficial phenomena such as tribology and catalysis. Among a few techniques available in this field, we are only concerned with the EXAFS-like ones (EXAFS, SEXAFS, EXELFS, SEELFS, etc.). The difficulties appearing all along the numerical treatment of such spectra are carefully analysed and a methodology is proposed in view to obtain reliable radial distribution functions. Some applications of these techniques are presented in two fields connected with tribology: friction induced amorphisation in high vacuum and characterization of interfacial solid bodies created during a wear process including an antiwear additive.
Źródło:
Acta Physica Polonica A; 1993, 83, 5; 551-566
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spinor representation of the electromagnetic field
Autorzy:
Tuladhar, B. Man
López-Bonilla, J.
Powiązania:
https://bibliotekanauki.pl/articles/1178035.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Faraday’s tensor
Lorentz transformations
Maxwell equations
Maxwell spinor
Newman-Penrose formalism
Quaternions
Opis:
We exhibit the tensor, spinor and Newman-Penrose (NP) forms of Faraday tensor and the Maxwell equations. Our approach is based in real and null tetrads, which allows introduce in natural manner the NP and 2-spinor techniques to study arbitrary electromagnetic fields, with special emphasis in the relationship between quaternions and Lorentz transformations.
Źródło:
World Scientific News; 2018, 95; 1-20
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of spermidine on germination of Salix spp. after storage under controlled conditions
Autorzy:
Wawrzyniak, M.K.
Ley-Lopez, J.M.
Kijowska-Oberc, J.
Chmielarz, P.
Ratajczak, E.
Powiązania:
https://bibliotekanauki.pl/articles/2130180.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
hydrogen peroxide
cryopreservation
spermidine
Salix
antioxidant
seed storage
Opis:
Willows produce fast germinating and short-lived seeds, difficult to store in the long-term under controlled conditions. The aim of this study was to examine the feasibility of storage of three Salix spp. at controlled temperatures (3°, −10°, −196 °C). We also analyzed the effect of spermidine (Spd) as an antioxidant factor in desiccated seeds. Collected seeds were either desiccated or hydrated to obtain 10 levels of moisture content (between app. 4% and 2%) and subjected to storage at temperatures 3°, −10°, or −196 °C (liquid nitrogen; LN). After two months, seeds were germinated on the light at 20 °C. Seeds desiccated below a safe range of moisture content were further tested and germinated on filter paper with additions of 0.25 mM Spd solution. After 7 days seedlings were examined for hydrogen peroxide content (H2O2) and total antioxidant capacity (TAC). Fresh seeds of three Salix species: Persian willow (S. aegyptiaca L.), heartleaf willow (S. cordata Michx.) and crack willow (S. ×fragilis L.) were successfully stored at temperature −10° and −196 °C for two months. After cryopreservation seed of S. aegyptiaca, S. cordata, and S. ×fragilis germinated without viability loss in moisture content ranging from 4.4–15.9%, 6.4–18.5%, and 7.1–11.5% respectively. The addition of Spd during germination of desiccated seed did not affect germination capacity. However, seedlings of S. aegyptiaca had lower hydrogen peroxide content in comparison with control (germination on water). Seedlings of S. cordata showed an increase in hydrogen peroxide content in control after storing in LN. In seedlings of Crack willow Spd increased hydrogen peroxide content. Seeds of tested species differ in response to storage conditions. Salix seeds can be stored successfully for two months at −10° or −196 °C without losing viability in the safe range of moisture content. Storing at 3 °C can be used for storage in the narrower range of seeds’ moisture content, however, seedlings stored at this temperature produce a higher level of reactive oxygen species. Germinating seeds in Spd did not increase their germination, however in S. aegyptiaca and S. cordata decreased hydrogen peroxide content.
Źródło:
Dendrobiology; 2022, 87; 137-148
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Identification of Gastric Cancer from Speckle Patterns
Autorzy:
Andrade-Eraso, C.
Patiño-Velasco, M.
Vásquez-López, J.
León, J.
Bolaños-Pantoja, G.
Trivi, M.
Powiązania:
https://bibliotekanauki.pl/articles/1490749.pdf
Data publikacji:
2012-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.68.+m
42.87.-d
87.50.W-
Opis:
Speckle technique is based on the light intensity distribution randomly formed when a laser light is reflected on a rough surface, creating a pattern of illuminated grains (constructively) and dark (destructive) on scales of 1 μm. When the samples are displaced or deformed, the speckle pattern is altered. In this paper we present speckle patterns obtained from samples of gastric mucosa that is physically altered for the carcinogenesis process. Biopsies were studied with different diagnoses and were grouped according to the characteristics of speckle patterns. Speckle patterns were obtained by illuminating the samples with green laser. Morphological parameters of the speckle patterns reveal existence of 3 descriptors: the average grain size, hydraulic radius and the radio of the Weddel disc, which showed a high, intermediate and low value. The comparison shows agreement between the histopathological diagnosis and the values obtained by the speckle technique, making this technique emerge as a new classification system for quantitative diagnosis of precancerous lesions.
Źródło:
Acta Physica Polonica A; 2012, 121, 1; 62-64
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Engine diagnosis based on vibration analysis using different fuel blends
Autorzy:
Grajales, J. A.
Quintero, H. F.
López, J. F.
Romero, C. A.
Henao, E.
Cardona, O.
Powiązania:
https://bibliotekanauki.pl/articles/328420.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
engine diagnosis
vibration analysis
frequency analysis
diagnostyka silnika
analiza drgań
analiza częstotliwościowa
Opis:
Fault diagnosis of an internal combustion engine is proposed herein by means of vibration analysis and a comparative analysis of normal operation and induced misfire scenarios. In order to validate previous works on misfire with pure gasoline, measurements also included tests performed with ethanol-gasoline fuel blends. According to results, changes in the fuel mix seem to have little impact on the performance and behaviour of the engine. And additionally, the particular frequency components that allowed differentiation between normal and faulty conditions were also present on all the fuel blends tested. Fast Fourier Transform was applied to obtain the frequency domain of the signal as a previous step to the subsequent identification process based on statistical characteristics extraction. A fuel blend classification method based on the analysis of the vibration signals of the engine was studied using envelope, Spike Energy and Peak Value techniques. Differentiation was possible with the extraction of the statistical features of the Peak Value spectrum of the longitudinal acceleration with a specific filter selection.
Źródło:
Diagnostyka; 2017, 18, 4; 27-36
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On operator ideals related to (p,σ)-absolutely continuous operators
Autorzy:
López Molina, J. A.
Sánchez Pérez, E. A.
Powiązania:
https://bibliotekanauki.pl/articles/1206151.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
tensor norms
operator ideals
(p,σ)-absolutely continuous operators
$g_{p,σ}$-nuclear and $g_{p,σ}$ integral operators
Opis:
We study tensor norms and operator ideals related to the ideal $P_{p,σ}$, 1 < p < ∞, 0 < σ < 1, of (p,σ)-absolutely continuous operators of Matter. If α is the tensor norm associated with $P_{p,σ}$ (in the sense of Defant and Floret), we characterize the $(α')^t$-nuclear and $(α')^t$- integral operators by factorizations by means of the composition of the inclusion map $L^r(μ) → L^1(μ) + L^p(μ)$ with a diagonal operator $B_w:L^{∞}(μ) → L^r(μ)$, where r is the conjugate exponent of p'/(1-σ). As an application we study the reflexivity of the components of the ideal $P_{p,σ}$.
Źródło:
Studia Mathematica; 2000, 138, 1; 25-40
0039-3223
Pojawia się w:
Studia Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Linearization of (second order operator)1/2
Autorzy:
López-Bonilla, J.
López-Vázquez, R.
Vidal-Beltrán, S.
Powiązania:
https://bibliotekanauki.pl/articles/1164128.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Cauchy-Riemann conditions
Laplacian operator
Pauli matrices
Weyl and Dirac equations
Opis:
We illustrate by means of the Pauli matrices how to linearize (second order operator)1/2 associated to the Weyl and Dirac equations. Besides, we exhibit the square root of the two dimensional Laplacian operator.
Źródło:
World Scientific News; 2018, 108; 224-228
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Matrices and orthogonal polynomials
Autorzy:
López-Bonilla, J.
López-Vázquez, R.
Vidal-Beltrán, S.
Powiązania:
https://bibliotekanauki.pl/articles/1177448.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Chebyshev
Hermite
Laguerre and Legendre polynomials
Lanczos algorithm
Leverrier-Takeno’s method
Three-member recurrence
Opis:
The Lanczos algorithm of minimized iterations shows that a polynomial verifying a three-term recurrence relation can be written as the determinant of a tridiagonal matrix, here we exhibit examples of this property. Besides, for several orthogonal polynomials, Cohen proved that their roots are the proper values of symmetric tridiagonal matrices; here we give examples of this Cohen’s result for the Legendre, Laguerre, and Hermite polynomials, which are important in applications to numerical analysis and quantum mechanics.
Źródło:
World Scientific News; 2018, 103; 234-241
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An alternative to Gower’s inverse matrix
Autorzy:
López-Bonilla, J.
López-Vázquez, R.
Vidal-Beltrán, S.
Powiązania:
https://bibliotekanauki.pl/articles/1177483.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Adjoint matrix
Characteristic equation
Eigenvalue problem
Faddeev-Sominsky’s method
Gower’s pseudoinverse matrix
Leverrier-Takeno’s algorithm
Opis:
We show that the Faddeev-Sominsky’s process allows construct a natural inverse for any square matrix, which is an alternative to the inverse obtained by Gower.
Źródło:
World Scientific News; 2018, 102; 166-172
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Differentiation of a Fourier series
Autorzy:
Cruz-Santiago, R.
López-Bonilla, J.
López-Vázquez, R.
Powiązania:
https://bibliotekanauki.pl/articles/1177486.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Fejér-Lanczos σ-Factors
Fourier series
Generalized derivative
Least squares method
Opis:
It is very known that if the operator d/dx acts on each term into a convergent Fourier series (FS) then it may result a divergent series. This situation is remedied applying the symmetric derivative to FS, which implies the existence of the important Fejér-Lanczos factors. In this note, we show that the orthogonal derivative also leads to these factors.
Źródło:
World Scientific News; 2018, 102; 188-192
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Motion of charged particles in Minkowski spacetime
Autorzy:
Caltenco, J. H.
López-Bonilla, J.
Piscoran, Laurian Ioan
Powiązania:
https://bibliotekanauki.pl/articles/1163835.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Faraday tensor
Liénard-Wiechert field
Minkowski spacetime
Superpotentials for the bounded and radiative parts of Maxwell tensor
Opis:
The electromagnetic field generated by a charge in arbitrary motion in Minkowski space is briefly studied. Particularly important is the deduction of superpotential for the radiative part of the Maxwell tensor.
Źródło:
World Scientific News; 2018, 108; 18-40
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Shifted Chebyshev-Lanczos polynomials
Autorzy:
Caltenco, J. H.
López-Bonilla, J.
Peña-Rivero, R.
Powiązania:
https://bibliotekanauki.pl/articles/1177824.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Feigenbaum constant
Modified Lanczos polynomials
Pascal triangle
Opis:
We show an algorithm for to express in terms of the modified Chebyshev-Lanczos polynomials , which is important to reduce the degree of a polynomial in the interval [0, 1]. Besides, with the use of into logistic map we obtain a simple geometric interpretation of the Feigenbaum´s universal constant.
Źródło:
World Scientific News; 2018, 99; 222-226
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Moore-Penrose’s inverse and solutions of linear systems
Autorzy:
López-Bonilla, J.
López-Vázquez, R.
Vidal-Beltrán, S.
Powiązania:
https://bibliotekanauki.pl/articles/1177742.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Least squares technique
Linear systems
Pseudoinverse of Moore-Penrose
SVD
Opis:
We employ the generalized inverse matrix of Moore-Penrose to study the existence and uniqueness of the solutions for over- and under-determined linear systems, in harmony with the least squares method.
Źródło:
World Scientific News; 2018, 101; 246-252
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analytics and data science applied to the trajectory outlier detection
Autorzy:
Lopez, Alexis J.
Quintero, Perfecto M.
Hernandez, Ana K.
Powiązania:
https://bibliotekanauki.pl/articles/117731.pdf
Data publikacji:
2020
Wydawca:
Polskie Towarzystwo Promocji Wiedzy
Tematy:
spatial-temporal data
trajectory outlier detection
trajectory clustering
dane przestrzenno-czasowe
wykrywanie wartości odstających trajektorii
grupowanie trajektorii
Opis:
Nowadays, logistics for transportation and distribution of merchandise are a key element to increase the competitiveness of companies. However, the election of alternative routes outside the panned routes causes the logistic companies to provide a poor-quality service, with units that endanger the appropriate deliver of merchandise and impacting negatively the way in which the supply chain works. This paper aims to develop a module that allows the processing, analysis and deployment of satellite information oriented to the pattern analysis, to find anomalies in the paths of the operators by implementing the algorithm TODS, to be able to help in the decision making. The experimental results show that the algorithm detects optimally the abnormal routes using historical data as a base.
Źródło:
Applied Computer Science; 2020, 16, 2; 5-17
1895-3735
Pojawia się w:
Applied Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Todorov’s formula involving Stirling numbers of the second kind and Nörlund polynomials
Autorzy:
Zúñiga-Segundo, A.
López-Bonilla, J.
Vidal-Beltrán, S.
Powiązania:
https://bibliotekanauki.pl/articles/1165650.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Bernoulli numbers
Duality property
Generalized chain rule of differentiation
Hoppe’s formula
Nörlund polynomials
Stirling numbers
Opis:
We use the Todorov’s formula for the generalized Bernoulli numbers, in terms of Stirling numbers of the second kind, to deduce the Guo-Qi and Schläfli identities. Our approach is based in the duality property between the Stirling numbers, and in the Nörlund polynomials. We also consider the Janjic’s definitions for the Stirling numbers.
Źródło:
World Scientific News; 2018, 107; 201-206
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Continuity equations in curved spaces
Autorzy:
Thapa, G. Bahadur
Hernández-Galeana, A.
López-Bonilla, J.
Powiązania:
https://bibliotekanauki.pl/articles/1167152.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Energy and momentum in curved spaces
Lagrangians in Riemannian spaces
Noether’s theorem
Rund-Lovelock’s relations
Opis:
In any Riemannian 4-space, we deduce continuity equations which could be interpreted as conservation laws for the energy and momentum of the gravitational field, with special emphasis in general relativity.
Źródło:
World Scientific News; 2018, 105; 197-203
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the Moore-Penrose generalized inverse matrix
Autorzy:
Thapa, G. Bahadur
Lam-Estrada, P.
López-Bonilla, J.
Powiązania:
https://bibliotekanauki.pl/articles/1178054.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Compatibility of linear systems
Moore-Penrose’s pseudoinverse
SVD
Opis:
We analyze the compatibility of linear systems and the uniqueness of the corresponding solution via the singular value decomposition of an arbitrary n x m matrix. Our approach leads in natural manner to the Moore-Penrose’s generalized inverse between the subspaces of activation of the matrix under study.
Źródło:
World Scientific News; 2018, 95; 100-110
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Relativistic motion of classical charged particles in a uniform electromagnetic field
Autorzy:
Caltenco, J. H.
López-Bonilla, J.
Vidal-Beltrán, S.
Powiązania:
https://bibliotekanauki.pl/articles/1177930.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Frenet-Serret formulae
Helixs in Minkowski spacetime
Lorentz equation
Opis:
Here we show the importance of a systematic method to generate any integer power of a matrix in 2, 3 and 4 dimensions. This is motivated by the integration of Frenet–Serret formulae for the case of constant curvatures, and by the relativistic motion of a point charge into a homogeneous electromagnetic field, because in such situations it is necessary to calculate being a scalar. By these reasons, we believe that this work can be useful for people interested in linear algebra, differential geometry and electrodynamics.
Źródło:
World Scientific News; 2018, 97; 153-167
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the Faddeev-Sominsky’s algorithm
Autorzy:
Torres-Silva, H.
López-Bonilla, J.
Vidal-Beltrán, S.
Powiązania:
https://bibliotekanauki.pl/articles/1166341.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Adjoint matrix
Characteristic equation
Eigenvalue problem
Faddeev-Sominsky’s method
Inverse matrix
Leverrier-Takeno’s algorithm
Resolvent of a matrix
Opis:
We comment that the Faddeev-Sominsky’s process to obtain an inverse matrix is equivalent to the Cayley-Hamilton-Frobenius theorem plus the Leverrier-Takeno’s method to construct the characteristic polynomial of an arbitrary matrix. Besides, we deduce the Lanczos expression for the resolvent of the corresponding matrix.
Źródło:
World Scientific News; 2018, 106; 238-244
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On eigenvectors associated to a multiple eigenvalue
Autorzy:
Cruz-Santiago, R.
López-Bonilla, J.
Vidal-Beltrán, S.
Powiązania:
https://bibliotekanauki.pl/articles/1177790.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Eigenvalue problem
Faddeev-Sominsky’s technique
Gower’s method
Opis:
If all roots of the characteristic polynomial of a matrix have distinct values, then the Faddeev-Sominsky’s algorithm gives the corresponding eigenvectors. Here we exhibit the method of Gower to construct the proper vectors associated to a multiple eigenvalue.
Źródło:
World Scientific News; 2018, 100; 248-253
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Lanczos potential for the Weyl tensor
Autorzy:
Morales, J.
Ovando, G.
López-Bonilla, J.
López-Vázquez, R.
Powiązania:
https://bibliotekanauki.pl/articles/1164250.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
2-spinors
Conformal tensor
Lanczos generator
Newman-Penrose formalism
Petrov classification
Spin coefficients
Weyl-Lanczos equations
Opis:
For arbitrary spacetimes with Petrov types O, N and III, we indicate general results about the Lanczos potential for the corresponding Weyl tensor.
Źródło:
World Scientific News; 2018, 108; 237-244
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Brans-Edgar-Ludwig equations for empty spacetimes
Autorzy:
Morales, J.
Ovando, G.
López-Bonilla, J.
Vidal-Beltrán, S.
Powiązania:
https://bibliotekanauki.pl/articles/1177881.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Bianchi identities
Brans-Edgar-Ludwig equations
Debever-Penrose principal directions
Null tetrad formalism
Petrov types
Opis:
We use the Newman-Penrose formalism to deduce the compatibility conditions for the Bianchi identities associated to vacuum spacetimes.
Źródło:
World Scientific News; 2018, 98; 199-205
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stirling numbers with negative indices
Autorzy:
Yaljá Montiel-Pérez, J.
López-Bonilla, J.
Vidal-Beltrán, S.
Powiązania:
https://bibliotekanauki.pl/articles/1177734.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Gould and Schläfli formulas
Stirling numbers
Opis:
We realize applications of expressions for Stirling numbers with negative indices, in particular, we show that the formulas of Zhi-Hong Sun are consequences of the known identities of Schläfli and Gould.
Źródło:
World Scientific News; 2018, 101; 217-221
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Atomic layer deposition as a tool of Surface engineering
Autorzy:
Tiznado, H.
Domínguez, D.
Borbón-Nuñez, H. A.
López, J.
Lizárraga, E.
Romo-Herrera, J. M.
Murillo-Bracamontes, E.
Soto, G.
Powiązania:
https://bibliotekanauki.pl/articles/1163971.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
ALD
Nanolaminates
Surface
nanotubes
Opis:
The applications of nanostructured materials are close related to their shape and properties. A comprehensive understanding of the properties modification by controlling the material size, thickness or shape is of key importance. A nanostructure can become a building block to create the upcoming nano-technological stages, where the final characteristics of devices can be fine-tuned from design. In this report it is shown that several physicochemical properties, such as refractive index, band gap or thermal resistance can be modified in a controlled fashion. ALD is a very versatile fabrication technique for building nanotubes (Al2O3 and TiO2), nanolaminates (Al2O3-ZnO, Y2O3-ZrO2 and ZrO2-TiO2) and core-shell materials (diamond-Al2O3) with an exquisite precision on the thickness of the coatings.
Źródło:
World Scientific News; 2018, 108; 99-110
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental and Theoretical Study of Zircon and Scheelite Phases of $DyVO_4$
Autorzy:
Ermakova, O.
Paszkowicz, W.
López-Solano, J.
Muñoz, A.
Dabkowska, H.
Powiązania:
https://bibliotekanauki.pl/articles/1431671.pdf
Data publikacji:
2012-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.70.Hj
61.43.Bn
61.66.Fn
Opis:
Polycrystalline zircon-type dysprosium orthovanadate, $DyVO_4,$ prepared from a single crystal grown by slow cooling from $PbO//PbF_2$ flux, was studied by X-ray diffraction. Rietveld refinement provided the following unit cell size and oxygen atom coordinates: a=7.14811(4) Å; c=6.30825(4) Å, V=322.323(3) Å3, y($O^{2-}$)=0.4300(4); z($O^{2-}$)=0.2082(4) which are of a particularly high accuracy and show consistency with earlier reported values. Density functional theory calculations within the generalized gradient approximation for the exchange-correlation energy were also performed, providing values of structure parameters which differ by less than 2% from the experimental ones. The agreement between theory and experiment demonstrates the value of these calculations for understanding the structure of compounds of $RVO_4$ family. In addition, density functional theory calculations were performed for the scheelite-type $DyVO_4$; also for this polymorph the discrepancy with the only known set of lattice parameters is less than 2%. Values of oxygen atom coordinates have not been reported yet for this polymorph; here, the calculated ones are quoted.
Źródło:
Acta Physica Polonica A; 2012, 121, 4; 920-927
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Propagators in quantum mechanics
Autorzy:
Hernández-Galeana, A.
Rivera-Rebolledo, J.
López-Bonilla, J.
López-Vázquez, R.
Powiązania:
https://bibliotekanauki.pl/articles/1177837.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Green’s functions
Propagators in quantum mechanics
Opis:
We consider one-dimensional non-relativistic quantum mechanics to exhibit that the propagators (Green’s functions) for free particle, linear potential and harmonic oscillator, are obtainable from purely classical means.
Źródło:
World Scientific News; 2018, 99; 249-253
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Linear differential equations of second, third, and fourth order
Autorzy:
Hernández-Galeana, A.
López-Bonilla, J.
López-Vázquez, R.
Vidal-Beltrán, S.
Powiązania:
https://bibliotekanauki.pl/articles/1167198.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Abel-Liouville-Ostrogradski identity
Euler-Lagrange method
Linear differential equation
Opis:
We study the linear differential equations of second, third, and fourth order, accepting to know solutions of the corresponding homogeneous equation, then we show how to obtain one more solution for the homogeneous case and a particular solution for the original equation.
Źródło:
World Scientific News; 2018, 105; 225-232
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Constraints and gauge relations in the Lagrangian formalism
Autorzy:
Lam-Estrada, P.
López-Bonilla, J.
López-Vázquez, R.
Vidal-Beltrán, S.
Powiązania:
https://bibliotekanauki.pl/articles/1178075.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Gauge identities
Genuine constraints
Local symmetries
Noether’s theorem
Singular Lagrangians
Opis:
For several Lagrangians we show that their local symmetries can be obtained from the associated Euler-Lagrange equations, and we exhibit the explicit presence of the genuine constraints into gauge identities. We also employ the Lanczos approach to Noether’s theorem to give connections between the genuine constraints and their time derivatives. Besides, it is evident that the Hamiltonian secondary and tertiary constraints have relationship with the genuine constraints.
Źródło:
World Scientific News; 2018, 95; 215-223
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Maxwell-Lorentz Matrix
Autorzy:
Montiel-Pérez, J. Yaljá
Pendleton, J.
López-Bonilla, J.
Vidal-Beltrán, S.
Powiązania:
https://bibliotekanauki.pl/articles/1177983.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Lorentz Group
Lorentz transformations
Maxwell equations
Opis:
Lorentz invariance of Maxwell electromagnetic equations is demonstrated in two complementary ways: first, we give a pedestrian review with three-vector equations, and we then express Maxwell equations in a four-vector matrix form (the Maxwell-Lorentz matrix) which demonstrates the intimate connection of Maxwell equations with the Lorentz group. Each Maxwell-Lorentz matrix component is the product of three matrices: a derivative matrix, a 4x4 Lorentz group generator matrix, and an electromagnetic field matrix. We obtain rotary Lorentz transformations of the electromagnetic field matrix from Lorentz equation matrices. We then transform the derivative and electromagnetic matrices and obtain an explicit matrix demonstration of Lorentz invariance of Maxwell equations. To obtain this result, we express all transformation matrices in exponential form to facilitate the application of simple Lorentz group algebra. The pedestrian approach illustrates what the Lorentz group matrix approach actually accomplishes and helps one to gain some appreciation of group theory methods.
Źródło:
World Scientific News; 2018, 96; 59-82
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On Stirling numbers
Autorzy:
Barrera-Figueroa, V.
López-Bonilla, J.
López-Vázquez, R.
Vidal-Beltrán, S.
Powiązania:
https://bibliotekanauki.pl/articles/1177886.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Generalized chain rule of differentiation
Hoppe’s formula
Stirling and Bernoulli numbers
Sums of powers of integers
Opis:
We exhibit an approach for the recursive formula obtained by Cereceda for the sums of powers of integers. Besides, we show that the definitions of Janjic for the Stirling numbers are consequences of the formulas of Hoppe and Quaintance-Gould.
Źródło:
World Scientific News; 2018, 98; 228-232
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Newman-Penrose’s formalism
Autorzy:
Lam-Estrada, P.
López-Bonilla, J.
López-Vázquez, R.
Vidal-Beltrán, S.
Powiązania:
https://bibliotekanauki.pl/articles/1177969.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Identities of Bianchi
Lanczos generator
Newman-Penrose equations
Weyl tensor
Opis:
We obtain the Newman-Penrose (NP) version of the Riemann tensor and the corresponding Bianchi identities. We also realize the NP transcription of the Weyl-Lanczos equations, and we emphasize that it is an open problem to find general solutions of this equations for the Petrov types I, II, and D, and to establish the possible physical meaning of the Lanczos potential.
Źródło:
World Scientific News; 2018, 96; 1-12
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Lanczos method
Autorzy:
Leija-Hernández, G.
López-Bonilla, J.
López-Vázquez, R.
Vidal-Beltrán, S.
Powiązania:
https://bibliotekanauki.pl/articles/1178014.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Eigenvalue problem
Lanczos algorithm
Minimized iterations
Opis:
The Lanczos technique is one of the most frequently used numerical algorithms in matrix computations. We note that this procedure is one of the top 10 algorithms that exerted the greatest influence in the development and practice of science and engineering in the 20th century. Here we give an elementary exposition of this Lanczos method to solve the algebraic eigenvalue problem.
Źródło:
World Scientific News; 2018, 96; 208-216
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Vector field in the reciprocal space
Autorzy:
Torres-Silva, H.
Barrera-Figueroa, V.
López-Bonilla, J.
Vidal-Beltrán, S.
Powiązania:
https://bibliotekanauki.pl/articles/1177958.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Reciprocal Space
Spatial Fourier transformation
Transverse and longitudinal δ-function
Opis:
As a preparation for the study of Maxwell equations under a spatial Fourier transform, we analyze properties of the transverse and longitudinal components of an arbitrary vector field in the reciprocal space.
Źródło:
World Scientific News; 2018, 97; 278-284
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Some applications of Noether’s theorem
Autorzy:
Montiel-Pérez, J. Yaljá
López-Bonilla, J.
López-Vázquez, R.
Vidal-Beltrán, S.
Powiązania:
https://bibliotekanauki.pl/articles/1166045.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Complex Riemann-Silberstein vector
Duality rotations
Ignorable variable
Invariance of the action
Lanczos variational method
Linear differential equation of second order
Maxwell equations
Noether’s theorem
Variation of parameters
Variational symmetry
Opis:
If the action S= ∫_(t_1)^(t_2)▒〖L(q,〗 (q,) ̇t) dt is invariant under the infinitesimal transformation t ̃=t+ε τ(q,t), q ̃_r= q_r+ε ξ_r (q,t),r=1,… ,n, with ε=constant ≪1, then the Noether’s theorem permits to construct the corresponding conserved quantity. The Lanczos approach employs to ε= q_(n+1) as a new degree of freedom, thus the Euler-Lagrange equation for this new variable gives the Noether’s constant of motion. Torres del Castillo and Rubalcava-García showed that each variational symmetry implies the existence of an ignorable coordinate; here we apply the Lanczos approach to the Noether’s theorem to motivate the principal relations of these authors. The Maxwell equations without sources are invariant under duality rotations, then we show that this invariance implies, via the Noether’s theorem, the continuity equation for the electromagnetic energy. Besides, we demonstrate that if we know one solution of p(x)y''+q(x)y'+r(x)y=0, then this Lanczos technique allows obtain the other solution of this homogeneous linear differential equation.
Źródło:
World Scientific News; 2018, 106; 69-80
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Identification of antimicrobial resistance genes in intestinal content from Coyote (Canis latrans)
Autorzy:
López-Islas, J.J.
Méndez-Olvera, ET.
Reyes C, T.
Martínez-Gómez, D.
Powiązania:
https://bibliotekanauki.pl/articles/16647515.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
antimicrobial resistance
metagenome
Canis latrans
Opis:
Antibiotic resistance has become a global public health concern in the last few years. Given the widespread rate of recurrence, increasing attention is being turned toward environmental pathways that potentially contribute to antibiotic resistance genes (ARGs) dissemination outside the clinical realm. In this study, a metagenome analysis of intestinal virus-like particle fraction (VLPs) from a wild coyote (Canis latrans) revealed for the first time, multiple ARGs, such as B-lactamases and multidrug efflux pumps. Description of ARGs presence in natural environments is critical to understand the emergence of resistant strains.
Źródło:
Polish Journal of Veterinary Sciences; 2023, 26, 1; 143-149
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The first record of Galba cubensis (L. Pfeiffer, 1839) (Mollusca: Gastropoda: Lymnaeidae) from open fields of Europe
Autorzy:
Schniebs, K.
Gloer, P.
Quinonero-Salgado, S.
Lopez-Soriano, J.
Hundsdoerfer, A.K.
Powiązania:
https://bibliotekanauki.pl/articles/83441.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Mikołaja Kopernika. Wydział Biologii i Ochrony Środowiska. Stowarzyszenie Malakologów Polskich
Źródło:
Folia Malacologica; 2018, 26, 1
1506-7629
Pojawia się w:
Folia Malacologica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
ReSySTER: A hybrid recommender system for Scrum team roles based on fuzzy and rough sets
Autorzy:
Colomo-Palacios, R.
González-Carrasco, I.
López-Cuadrado, J. L.
García-Crespo, Á.
Powiązania:
https://bibliotekanauki.pl/articles/331282.pdf
Data publikacji:
2012
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
zbiór rozmyty
zbiór przybliżony
Scrum
pakiet roboczy
system polecenia
fuzzy set
rough set
work package
recommender system
Opis:
Agile development is a crucial issue within software engineering because one of the goals of any project leader is to increase the speed and flexibility in the development of new commercial products. In this sense, project managers must find the best resource configuration for each of the work packages necessary for the management of software development processes in order to keep the team motivated and committed to the project and to improve productivity and quality. This paper presents ReSySTER, a hybrid recommender system based on fuzzy logic, rough set theory and semantic technologies, aimed at helping project leaders to manage software development projects. The proposed system provides a powerful tool for project managers supporting the development process in Scrum environments and helping to form the most suitable team for different work packages. The system has been evaluated in a real scenario of development with the Scrum framework obtaining promising results.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2012, 22, 4; 801-816
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Laboratory of Natural Radiation (LNR) : a place to test radon instruments under variable conditions of radon concentration and climatic variables
Autorzy:
Quindós Poncela, L. S.
Sainz Fernández, C.
Gutiérrez-Villanueva, J.-L.
Fuente Merino, I.
Celaya González, C.
Quindós López, L.
Quindós López, J.
Fernández Lopez, E.
Fernández Villar, A.
Powiązania:
https://bibliotekanauki.pl/articles/147764.pdf
Data publikacji:
2016
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
active monitors
interlaboratory comparison
in-situ
radon
Opis:
The publication of the new European Union Basic Safety Standards represents a remarkable milestone in the fi eld of radiological protection in terms of adding radon exposure to this framework. Therefore, the coming years will bring the need to measure radon not only in the workplaces but also in the living spaces as a direct outcome of the application of the new EU Directive. So, the importance of having reliable instruments is evident and interlaboratory exercises are becoming more and more popular. However, most of them are carried out under constant conditions of meteorological variables. We present in this paper a facility to broaden the interlaboratory comparisons further by adding the study of radon exposures under real conditions of changes in climatic parameters. In addition, the facility has the possibility to verify the response of radon monitors when the radon concentration changes several orders of magnitude in a short period of time. Our work shows some results of one of the interlaboratory exercises carried out in the premises, where the radon levels were rather homogeneous in the testing room.
Źródło:
Nukleonika; 2016, 61, 3; 275-280
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Importance of Internet And Online Social Networks in the Spanish Hotel Sector
Autorzy:
Infante-Moro, A.
Infante-Moro, J-C.
Martínez-López, F-J.
García-Ordaz, M.
Powiązania:
https://bibliotekanauki.pl/articles/118135.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Promocji Wiedzy
Tematy:
hotels
online social networks
internet
e-commerce
cross-sectional study
Opis:
This paper is a cross-sectional study on the use of Internet and Online Social Networks in the Spanish hotel sector compared to Spanish companies in other sectors. The conclusions from this extensive survey are that the use of online social networks is more important and is more developed in the hotel sector than in Spanish companies in general. However, although it gives considerable importance to online social networks, the hotel sector needs to revise its rules of usage. The use of new tools such as e-commerce to sell the hotel stays must increase, and marketing efforts should be geared more towards online social networks because the hotel sector is currently losing ground in a market that generates more and more potential clients and sales by the day.
Źródło:
Applied Computer Science; 2016, 12, 1; 75-86
1895-3735
Pojawia się w:
Applied Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Noether and matrix methods to construct local symmetries of Lagrangians
Autorzy:
Lam-Estrada, P.
Ovando, G.
López-Bonilla, J.
López-Vázquez, R.
Vidal-Beltrán, S.
Powiązania:
https://bibliotekanauki.pl/articles/1177899.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Gauge identities
Local symmetries
Noether theorem
Singular Lagrangians
Opis:
We exhibit an elementary presentation of matrix and Noether techniques to construct infinitesimal point symmetries of Lagrangians. Besides, we employ the Lanczos approach to Noether’s theorem to obtain the first integral associated with each symmetry. We show applications to several singular Lagrangians of interest in classical mechanics.
Źródło:
World Scientific News; 2018, 97; 51-68
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spacetimes embedded into E6
Autorzy:
Montiel-Pérez, J. Yaljá
Caltenco, J. H.
Linares y M., R.
López-Bonilla, J.
Powiązania:
https://bibliotekanauki.pl/articles/1164540.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
E6
Embedding of Riemannian 4-spaces
Local and isometric embedding
Opis:
We study the local and isometric embedding of Riemannian spacetimes into the pseudo-Euclidean flat E6. Our main purpose is to pinpoint the known results with the corresponding references, and to indicate the main routes and connections from here to the still open problems in the field. Some new results are also included in order to round off our discussion.
Źródło:
World Scientific News; 2018, 107; 31-45
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-50 z 92

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