Autor: Szyszkowicz, Mieczyslaw - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Some problems connected with the absolute stability of explicit one-step methods
Autorzy:: Szyszkowicz, Mieczysław
Powiązania:: https://bibliotekanauki.pl/articles/748597.pdf
Data publikacji:: 1985
Wydawca:: Polskie Towarzystwo Matematyczne
Tematy:: Stability and convergence of numerical methods
Opis:: .
Regions of absolute stability for several examples of Runge-Kutta methods, Bobkov methods, Richardson extrapolation of Runge-Kutta methods are investigated. For the Richardson extrapolation of Runge-Kutta methods the method with maximal order of convergence is found.
Źródło:: Mathematica Applicanda; 1985, 13, 26
1730-2668
2299-4009
Pojawia się w:: Mathematica Applicanda
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: An approach to represent a combined exposure to air pollution
Autorzy:: Szyszkowicz, Mieczyslaw
Powiązania:: https://bibliotekanauki.pl/articles/2177164.pdf
Data publikacji:: 2015-07-17
Wydawca:: Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:: ambient air pollution
case-crossover
odds ratio
index
emergency department visit
air pollution
Opis:: Objectives The objective of this study was to present a technique for estimating the effect of ambient air pollution mix on health outcomes. Material and Methods We created a technique of indexing air pollution mix as a cause of the increased odds of health problems. As an illustrative example, we analyzed the impact of pollution on the frequency of emergency department (ED) visits due to colitis among young patients (age < 15 years, N = 11 110). Our technique involves 2 steps. First, we considered 6 ambient air pollutants (carbon monoxide, nitrogen dioxide, sulphur dioxide, ozone, and 2 measures of particulate matter) treating each pollutant as a single exposure. Odds ratios (ORs) for ED visits associated with a standard increase (interquartile range – IQR) in the pollutants levels were calculated using the case-crossover technique. The ORs and their 95% confidence intervals (95% CIs) were also found for lagged exposures (for lags 1–9 days). Second, we defined a Health Air Study Index (HASI) to represent the combined impact of the 6 air pollutants. Results We obtained positive and statistically significant results for individual air pollutants and among them the following estimations: OR = 1.06 (95% CI: 1.02–1.1, NO₂ lag 3, IQR = 12.8 ppb), OR = 1.04 (95% CI: 1.01–1.07, SO₂ lag 4, IQR = 2.3 ppb), OR = 1.04 (95% CI: 1–1.06, PM lag 3, IQR = 6.2 μg/m³). Among the re-calculated ORs with the HASI values as an exposure, the highest estimated value was OR = 1.37 (95% CI: 1.12–1.68, for 1 unit of the HASI, lag 3). Conclusions The proposed index (HASI) allows to confirm the pattern of associations for lags obtained for individual air pollutants. In the presented example the used index (HASI) indicates the strongest relation with the exposure lagged by 3 days.
Źródło:: International Journal of Occupational Medicine and Environmental Health; 2015, 28, 5; 823-830
1232-1087
1896-494X
Pojawia się w:: International Journal of Occupational Medicine and Environmental Health
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Determining the step of integration for the one-step Bobkovs methods
Autorzy:: Szyszkowicz, Mieczysław
Powiązania:: https://bibliotekanauki.pl/articles/748261.pdf
Data publikacji:: 1985
Wydawca:: Polskie Towarzystwo Matematyczne
Tematy:: Initial value problems
Automated algorithms
Opis:: .
Consider the class of Bobkov methods for solving the IVP: y′=f(x,y), x[a,b]. Four procedures for finding the step size h are presented. It is shown that these Bobkov methods with automatic stepsize control are faster (i.e. need fewer evaluations of f) than the corresponding Runge-Kutta methods.
Źródło:: Mathematica Applicanda; 1985, 13, 25
1730-2668
2299-4009
Pojawia się w:: Mathematica Applicanda
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Rysunek komputerowy Mieczysława Szyszkowicza z Ottawy
Autorzy:: Szyszkowicz, Mieczysław
Powiązania:: https://bibliotekanauki.pl/articles/748499.pdf
Data publikacji:: 1991
Wydawca:: Polskie Towarzystwo Matematyczne
Tematy:: .
Opis:: Artykuł nie zawiera streszczenia
The article contains no abstract
Źródło:: Mathematica Applicanda; 1991, 19, 33
1730-2668
2299-4009
Pojawia się w:: Mathematica Applicanda
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Case-crossover design: Air pollution and health outcomes
Autorzy:: Szyszkowicz, Mieczysław
Tremblay, Neil
Powiązania:: https://bibliotekanauki.pl/articles/2185393.pdf
Data publikacji:: 2011-09-01
Wydawca:: Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:: air pollution
city
depression
emergency department
humidity
temperature
nitrogen dioxide
sulphur dioxide
Opis:: Objectives: The objective of this study was to investigate variants of case-crossover design for assessing correlations between counts of health events over time and exposure to ambient air pollution. For illustrative purposes, daily emergency department (ED) visits for depression among females were considered. Materials and Method: Ambient nitrogen dioxide (NO₂) was used as a principal ambient air pollutant. In addition, sulphur dioxide (SO₂) and carbon monoxide (CO) were considered. Different configurations of the control periods (every 1, 2, …, 10 days) and different forms (linear, natural splines) of meteorological factors in the applied conditional logistic regression models were used. The sequence of overlapping age intervals was defined ([0, 19], [1, 20], and so on) and each age group was analyzed separately. The results for the defined age sequences allow identifying age ranges in which the effects are strongest. Results: Consequently, for example, different age ranges for patients for which ED visits for depression were correlated with NO₂ and SO₂ were identified. This age-interval difference explains the very often observed phenomenon whereby two air pollutants used in one model may not show correlations with health outcomes. In this situation they affect separate age groups. The results also show dependency on number-defined control periods for the applied case-crossover technique. The opposite statistical conclusions may be generated by using different control schemas. Conclusions: The results support the hypothesis that ED visits for depressive disorder may be correlated with exposure to ambient air pollution.
Źródło:: International Journal of Occupational Medicine and Environmental Health; 2011, 24, 3; 249-255
1232-1087
1896-494X
Pojawia się w:: International Journal of Occupational Medicine and Environmental Health
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: The use of chained two-point clusters for the examination of associations of air pollution with health conditions
Autorzy:: Szyszkowicz, Mieczysław
Burr, Wesley S.
Powiązania:: https://bibliotekanauki.pl/articles/2177423.pdf
Data publikacji:: 2016-05-25
Wydawca:: Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:: ambient air pollution
Mortality
case-crossover
cluster
relative risk
odds ratio
Opis:: Objectives There are a few accepted and intensively applied statistical methods used to study associations of ambient air pollution with health conditions. Among the most popular methods applied to assess short term air health effects are case-crossover (using events) and time-series methodologies (using counts). A few other techniques for studying counts of events have been proposed, including the Generalized Linear Mixed Models (GLMM). One suggested GLMM technique uses cluster structures based on natural embedded hierarchies: days are nested in the days of a week (dow), which, in turn, are nested in months and months in years (< dow, month, years >). Material and Methods In this study the authors considered clusters with hierarchical structures in a form of < dow, 14-days, year >, where the 14-days hierarchy determines 7 clusters composed of 2 days (the same days) of a week (2 Mondays, 2 Tuesdays, etc.), in 1 year. In this work the authors proposed hierarchical chained clusters in which 2 days of a week are grouped as follows: (first, second), (second, third), (third, fourth) and so on. Such an approach allows determination of an additional series of the slopes on the clusters (second, third), (fourth, fifth), etc., i.e., estimation of the coefficients for other configurations of air pollutant levels. The authors considered a series of 2 point chained clusters covering a year. In such a construction each cluster has one common data point (day) with another one. Results The authors estimated coefficients (slopes) related to the ambient ozone exposure (mortality) and to 3 selected air pollutants (particulate matter, nitrogen dioxide and ozone) combined into index and considered as health risk exposure (emergency department (ED) visits). The generated results were compared to the estimations obtained from the time-series method and the time-stratified case-crossover method applied to the same data. Conclusions The proposed statistical method, based on the chained hierarchical clusters (< dow, 14-days, year >), generated results with shorter confidence intervals than the other methods.
Źródło:: International Journal of Occupational Medicine and Environmental Health; 2016, 29, 4; 613-622
1232-1087
1896-494X
Pojawia się w:: International Journal of Occupational Medicine and Environmental Health
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Air pollution and emergency department visits for conjunctivitis: A case-crossover study
Autorzy:: Szyszkowicz, Mieczysław
Kousha, Termeh
Castner, Jessica
Powiązania:: https://bibliotekanauki.pl/articles/2177432.pdf
Data publikacji:: 2016-02-02
Wydawca:: Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:: air pollution
case-crossover
emergency department visit
exposure
conjunctivitis
multi-city study
Opis:: Objectives The purpose of this study was to examine the associations between emergency department (ED) visits for conjunctivitis and ambient air pollution levels in urban regions across the province of Ontario, Canada. Material and Methods Information from the National Ambulatory Care Reporting System was used to create time-series records, for the period of April 2004 to December 2011, on emergency department visits of patients suffering from conjunctivitis. A total of 77 439 emergency department visits for conjunctivitis were analyzed. A time-stratified case-crossover design was applied, completed with meta-analysis in order to pool inter-city results. Odds ratio (OR) for an emergency department visit was calculated in different population strata per one-unit increase (one interquartile range – IQR increase in a pollutant’s daily level) while controlling for the impacts of temperature and relative humidity. Results Statistically significant positive results were observed in the female population sample, for nitrogen dioxide (NO₂) exposure lagged 5–8 days, with the highest result for the 7-day lag (OR = 1.035, 95% CI: 1.018–1.052) and for fine particulate matter with a median aerodynamic diameter of less than 2.5 μm ($\text{PM}_\text{2.5}$), for lags 6 and 7 days, with the highest result for lag 7 (OR = 1.017, 95% CI: 1.003–1.031). In the male population sample, statistically significant positive results were observed for NO₂ at lag 5 days (OR = 1.024, 95% CI: 1.004–1.045) and for ozone (O₃), at lags 0–3 and 7 days, with the highest result for lag 0 (OR = 1.038, 95% CI: 1.012–1.056). Also for males, statistically significant results were observed in the case of $\text{PM}_\text{2.5}$ exposure lagged by 5 days (OR = 1.003, 95% CI: 1.000–1.038) and sulfur dioxide (SO₂) exposure lagged by 1 and 2 days (OR = 1.016, 95% CI: 1.000–1.031 and OR = 1.018, 95% CI: 1.002–1.033). Conclusions The findings of this study suggest that there are associations between levels of air pollution and ED visits for conjunctivitis, with different temporal trends and strength of association by age, sex, and season.
Źródło:: International Journal of Occupational Medicine and Environmental Health; 2016, 29, 3; 381-393
1232-1087
1896-494X
Pojawia się w:: International Journal of Occupational Medicine and Environmental Health
Dostawca treści:: Biblioteka Nauki

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