Several ecologic factors have been proposed to describe the mechanisms whereby host ecology and the environment influence the transmission of avian influenza viruses (AIVs) in wild birds, including bird's foraging behavior, migratory pattern, seasonal congregation, the rate of recruitment of juvenile birds, and abiotic factors. However, these ecologic factors are derived from studies that have ...

abiotic factors, as topographic and physicochemical properties of soil, are the most important effective factor on vegetation in rangeland ecosystems which have the most important performances to forming and succession of plant vegetation. ecologic management of rangelands can be desired by better understanding of these effective factors. then, rangeland of javaherdeh (ramsar) in the northern a...

A number of authors have attempted to defend ecologic (aggregate) studies by claiming that the goal of those studies is estimation of ecologic (contextual or group-level) effects rather than individual-level effects. Critics of these attempts point out that ecologic effect estimates are inevitably used as estimates of individual effects, despite disclaimers. A more subtle problem is that ecolog...

BACKGROUND As ecologic studies are often inexpensive to conduct, consideration of the magnitude and direction of ecologic biases may be useful in both study design and sensitivity analysis of results. This paper examines three types of ecologic bias: confounding by group, effect measure modification by group, and non-differential exposure misclassification. METHODS Bias of the risk difference...

The zoonotic disease tularemia is endemic in large areas of the Northern Hemisphere, but research is lacking on patterns of spatial distribution and connections with ecologic factors. To describe the spatial epidemiology of and identify ecologic risk factors for tularemia incidence in Sweden, we analyzed surveillance data collected over 29 years (1984-2012). A total of 4,830 cases were notified...

Atmospheric leakage between a CELSS and its surround is driven by the differential pressure between the two. In an earth-based CELSS, both negative and positive differential pressures of atmosphere are created as the resultant of three influences: thermal expansion/contraction, transition of water between liquid and vapor phases, and external barometric pressure variations. The resultant may ty...

abstract the objective of current research is to investigate distribution patterns of vegetation types and its relation with environmental factors in southern margin of haj aligholi kavir of damghan. three vegetation types including halecnemum strobilaceum, sedlitzia rosmarinus and artemisia sieberi were studied in marginal arid regions and uplands of the study area. firstly, geographic locatio...