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Wyszukujesz frazę "peak test" wg kryterium: Temat


Wyświetlanie 1-6 z 6
Tytuł:
Trends in monthly, seasonal, and annual fluctuations in flood peaks for the upper Dniester River
Autorzy:
Melnyk, Serhii
Loboda, Nataliia
Powiązania:
https://bibliotekanauki.pl/articles/1445135.pdf
Data publikacji:
2020
Wydawca:
Instytut Meteorologii i Gospodarki Wodnej - Państwowy Instytut Badawczy
Tematy:
Mann-Kendall test
Dniester
peak over threshold
daily runoff maxima
trends in changes in maximum
Opis:
The importance of the Dniester River in the socio-economic life of Moldova and Ukraine necessitates research into the main trends in the river’s runoff characteristics and dynamics, especially now, when climate change is significantly altering the water regime of rivers. This paper presents a solution for the problems of identifying the main trends in daily maximum river discharge by seasons and months for various calculation intervals. Two calculation intervals (1981-1998; 1999-2015) with different climatic conditions are considered. Each interval corresponds to one complete cycle of river water discharge. Climatic conditions as a result of global warming are changing differently in the mountains and on the plain, therefore, the identification of trends was performed separately for the alpine and lowland parts of the Dniester River annual runoff formation zone. The search for statistically significant trends was carried out by means of the MannKendall test. The analysis of the frequency of maximum discharges (peak over threshold; POT3) was performed for selected rivers in the studied area. The earlier period (1981-1998) showed statistically significant positive trends for both alpine and lowland rivers of the Upper Dniester. The later period (1999-2015) differed, exhibiting exclusively negative significant trends in daily peaks both by months and by seasons. This result indicates a persistent tendency toward decreasing maximum water runoff for all rivers of the Upper Dniester catchment. There were no statistically significant trends in the frequency of floods.
Źródło:
Meteorology Hydrology and Water Management. Research and Operational Applications; 2020, 8, 2; 28-36
2299-3835
2353-5652
Pojawia się w:
Meteorology Hydrology and Water Management. Research and Operational Applications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Regional resting state perfusion variability and delayed cerebrovascular uniform reactivity in subjects with chronic carotid artery stenosis
Autorzy:
Szarmach, Arkadiusz
Kaszubowski, Mariusz
Sabisz, Agnieszka
Frydrychowski, Andrzej
Halena, Grzegorz
Piskunowicz, Maciej
Dzierzanowski, Jarosław
Studniarek, Michał
Szurowska, Edyta
Winklewski, Pawel
Powiązania:
https://bibliotekanauki.pl/articles/1038538.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
chronic carotid artery stenosis
computed tomography perfusion
acetazolamide test
cerebral blood flow
cerebral blood volume
mean transit time
time to peak
Opis:
The aim of this study was to assess regional perfusion at baseline and regional cerebrovascular resistance (CVR) to delayed acetazolamide challenge in subjects with chronic carotid artery stenosis. Sixteen patients (ten males) aged 70.94±7.71 with carotid artery stenosis ≥ 90% on the ipsilateral side and ≤ 50% on the contralateral side were enrolled into the study. In all patients, two computed tomography perfusion examinations were carried out; the first was performed before acetazolamide administration and the second 60 minutes after injection. The differences between mean values were examined by paired two-sample t-test and alternative nonparametric Wilcoxon's test. Normality assumption was examined using W Shapiro-Wilk test. The lowest resting-state cerebral blood flow (CBF) was observed in white matter (ipsilateral side: 18.4±6.2; contralateral side: 19.3±6.6) and brainstem (ipsilateral side: 27.8±8.5; contralateral side: 29.1±10.8). Grey matter (cerebral cortex) resting state CBF was below the normal value for subjects of this age: frontal lobe - ipsilateral side: 30.4±7.0, contralateral side: 33.7±7.1; parietal lobe - ipsilateral side: 36.4±11.3, contralateral side: 42.7±9.9; temporal lobe - ipsilateral side: 32.5±8.6, contralateral side: 39.4±10.8; occipital lobe - ipsilateral side: 24.0±6.0, contralateral side: 26.4±6.6). The highest resting state CBF was observed in the insula (ipsilateral side: 49.2±17.4; contralateral side: 55.3±18.4). A relatively high resting state CBF was also recorded in the thalamus (ipsilateral side: 39.7±16.9; contralateral side: 41.7±14.1) and cerebellum (ipsilateral side: 41.4±12.2; contralateral side: 38.1±11.3). The highest CVR was observed in temporal lobe cortex (ipsilateral side: +27.1%; contralateral side: +26.1%) and cerebellum (ipsilateral side: +27.0%; contralateral side: +34.6%). The lowest CVR was recorded in brain stem (ipsilateral side: +20.2%; contralateral side: +22.2%) and white matter (ipsilateral side: +18.1%; contralateral side: +18.3%). All CBF values were provided in milliliters of blood per minute per 100 g of brain tissue (ml/100g/min). Resting state circulation in subjects with carotid artery stenosis is low in all analysed structures with the exception of insula and cerebellum. Acetazolamide challenge yields relatively uniform response in both hemispheres in the investigated population. Grey matter is more reactive to acetazolamide challenge than white matter or brainstem.
Źródło:
Acta Biochimica Polonica; 2018, 65, 1; 151-162
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A laboratory investigation on shear strength behavior of sandy soil: effect of glass fiber and clinker residue content
Autorzy:
Bouaricha, L.
Djafar Henni, A.
Lancelot, L.
Powiązania:
https://bibliotekanauki.pl/articles/178431.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
direct shear test
glass fibers
clinker residue
peak shear stress
sand
normal stress
cohesion
frictional angle
Opis:
A study was undertaken to investigate the shear strength parameters of treated sands reinforced with randomly distributed glass fibers by carrying out direct shear test after seven days curing periods. Firstly, we studied the fiber content and fiber length effect on the peak shear strength on samples. The second part gives a parametric analysis on the effect of glass fiber and clinker residue content on the shear strength parameters for two types of uniform Algerian sands having different particle sizes (Chlef sand and Rass sand) with an average relative density Dr = 50%. Finally, the test results show that the combination of glass fiber and clinker residue content can effectively improve the shear strength parameters of soil in comparison with unreinforced soil. For instance, there is a significant gain for the cohesion and friction angle of reinforced sand of Chlef. Compared to unreinforced sand, the cohesion for sand reinforced with different ratios of clinker residue increased by 4.36 to 43.08 kPa for Chlef sand and by 3.1 to 28.64 kPa for Rass sand. The feature friction angles increased from 38.73° to 43.01° (+4.28°), and after the treatment, clinker residue content of soil evaluated to 5% (WRC = 5%).
Źródło:
Studia Geotechnica et Mechanica; 2017, 39, 4; 3-15
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Assessing peak aerobic capacity in Dutch law enforcement officers
Autorzy:
Wittink, Harriet
Takken, Tim
de Groot, Janke
Reneman, Michiel
Peters, Roelof
Vanhees, Luc
Powiązania:
https://bibliotekanauki.pl/articles/2177371.pdf
Data publikacji:
2015-05-18
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
aerobic capacity
VO2peak
prediction equations
maximal exercise test
bicycle protocol
law enforcement officers
Opis:
Objectives To cross-validate the existing peak rate of oxygen consumption (VO₂peak) prediction equations in Dutch law enforcement officers and to determine whether these prediction equations can be used to predict VO₂ₚₑₐₖ for groups and in a single individual. A further objective was to report normative absolute and relative VO₂ₚₑₐₖ values of a sample of law enforcement officers in the Netherlands. Material and Methods The peak rate of oxygen consumption (ml×kg⁻¹×min⁻¹) was measured using a maximal incremental bicycle test in 1530 subjects, including 1068 male and 461 female police officers. Validity of the prediction equations for groups was assessed by comparing predicted VO₂ₚₑₐₖ with measured VO₂ₚₑₐₖ using paired t-tests. For individual differences limits of agreement (LoA) were calculated. Equations were considered valid for individuals when the difference between measured and predicted VO₂ₚₑₐₖ did not exceed ±1 metabolic equivalent (MET) in 95% of individuals. Results None of the equations met the validity criterion of 95% of individuals having ±1 MET difference or less than the measured value. Limits of agreement (LoAs) were large in all predictions. At the individual level, none of the equations were valid predictors of VO₂ₚₑₐₖ (ml×kg⁻¹×min⁻¹). Normative values for Dutch law enforcement officers were presented. Conclusions Substantial differences between measured and predicted VO₂ₚₑₐₖ (ml×kg⁻¹×min⁻¹) were found. Most tested equations were invalid predictors of VO₂ₚₑₐₖ at group level and all were invalid at individual levels.
Źródło:
International Journal of Occupational Medicine and Environmental Health; 2015, 28, 3; 519-531
1232-1087
1896-494X
Pojawia się w:
International Journal of Occupational Medicine and Environmental Health
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Observations from the Analysis of Searching Peak of Tension Test (SPOT) Charts
Autorzy:
Jaworski, Ryszard
Powiązania:
https://bibliotekanauki.pl/articles/523317.pdf
Data publikacji:
2015-03-01
Wydawca:
Krakowska Akademia im. Andrzeja Frycza Modrzewskiego
Tematy:
Peak of Tension Test (POT)
Searching Peak of Tension (SPOT)
Źródło:
European Polygraph; 2015, 9, 1; 25-52
1898-5238
2380-0550
Pojawia się w:
European Polygraph
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Homoscedasticity test for the linear trend
Testy homoskedastycznośd dla modelu liniowego
Autorzy:
Domański, Czesław
Powiązania:
https://bibliotekanauki.pl/articles/905620.pdf
Data publikacji:
2002
Wydawca:
Uniwersytet Łódzki. Wydawnictwo Uniwersytetu Łódzkiego
Tematy:
F-test
peak test
Goldfeld-Quandt test
Kendal statistic homoscedasticity
heteroscedastidty
Fc statistic test power
quantiles
Opis:
W literaturze statystycznej i ekonometrycznej bardzo wyraźnie podkreśla się znaczenie i metody weryfikacji podstawowych założeń dotyczących modelu ekonometrycznego, chociaż w praktyce niezbyt często postulat ten jest realizowany.
Abstract. In this paper we consider single parameter models of heteroscedastidty: linear, square, exponential, group. A significant predominance of the parametric tests over the peak tests is shown using the variability coefficient as the most natural measure of homosccdasticity and the summary Kendal statistic as a measure of a test power. Another suggestion is that it is worth using the Goldfeld-Quandt parametric test, when the growth in the variance is quite „smooth” (in other case - the classical F-lesl is better). Prevalence of the F-test over the peak test is much smaller.
Źródło:
Acta Universitatis Lodziensis. Folia Oeconomica; 2002, 156
0208-6018
2353-7663
Pojawia się w:
Acta Universitatis Lodziensis. Folia Oeconomica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-6 z 6

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