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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: Journal of Statistical Modelling: Theory and Applications
- نوع مقاله: Journal Article
- کلمات کلیدی: Cross-pair correlation function,Hidden Gaussian random field,Intensity dependent marking model,Mark variogram
- چکیده:
- چکیده انگلیسی: This paper aims to conduct a model-based analysis of the spatial patterns of three tree species in a Hyrcanian forest and investigate their associations. There are many known and unknown mechanisms that influence the spatial forest structure and species associations. These complex and mainly unobservable mechanisms can be modeled by hidden Gaussian random fields and log-Gaussian Cox process models are appropriate for linking them to the spatial patterns of tree species. We consider a multivariate log-Gaussian Cox process model that can take into account the overall mixed effects of all influential factors on spatial distributions of species and quantify species associations in terms of some parameters. This construction provides a suitable framework for modeling and analyzing spatial patterns of several species. We also discuss modeling tree diameters, parameter estimation and goodness of fit methods and apply them to the data. Results from fitting the model to the data show that there is a significant negative association between two light-demanding species. Finally, a Gamma intensity-dependent model is considered to model spatial correlation in tree diameters of one of the species.
- انتشار مقاله: 04-08-1398
- نویسندگان: Abdollah Jalilian,Amir Safari,Hormoz Sohrabi
- مشاهده
- جایگاه : پژوهشی
- مجله: Asia Pacific Journal of Medical Toxicology
- نوع مقاله: Journal Article
- کلمات کلیدی: Risk,Air pollution,Exposure,Circadian Rhythm,Inhalation Rate
- چکیده:
- چکیده انگلیسی: Background: Diurnal sequences of activities conducted at several locations visited by individuals have an impact on population exposure to air pollution. However, data on individual's movement with a fine time resolution is rare.
Methods: In the current study, 399 children and adolescents (aged 11–18 years) from Isfahan city were asked to recall their 24-hour diary during winter and spring 2014-2015. Daily ventilation rates for individuals were calculated using Consolidated Human Activity Database (CHAD) and were subject to cosinor analysis.
Results: There was a significant circadian rhythm in inhalation rate, outdoor time-spent and ambient NO2 pollution. The ANOVA of rhythm parameters showed a significant difference (P < 0.05) between gender groups and day types, whereas the difference between age groups and seasons was not significant. Analysis of results showed that increased NO2 pollution was concurrent with increased inhalation rate and outdoor time-spent. Inhalation rates obtained for population groups were 9.3, 11.6, 9.0 and 11.3 L/min for high school girls, high school boys, elementary girls and elementary boys, respectively. Elementary boys were at higher risk of exposure to air pollution. Boys spent more time outdoors and in traffic than girls. Respondents spent 89% of their time inside and 82% of their inside time at home. They also spent 10% of their time during a year in school. Respondents were exposed to cooking generated pollutants 11 times a week. Among them, 30% were exposed to second-hand smoke, and 86.3% reported in very good health.
Conclusion: We concluded that actual exposure levels may be underestimated when the simple risk assessment method is implemented without the survey of fine time resolution spatiotemporal activity data.- انتشار مقاله: 16-10-1395
- نویسندگان: Zeinab Rafiei,Abbas Esmaili-Sari,Hormoz Sohrabi,Nader Bahramifar
- مشاهده