The recognition of seasonal patterns in infectious disease occurrence dates back at least as far as the hippocratic era, but the mechanisms underlying these fluctuations remain poorly understood. Many classes of mechanistic hypotheses have been proposed to explain seasonality of various directly transmitted diseases, including at least the following; human activity, seasonal variability in huma...

Seasonal heteroskedasticity refers to regular changes in variability over the calendar year. Models for two different forms of seasonal heteroskedasticity were recently proposed by Proietti and by Bell. We examine use of likelihood ratio tests with the models to test for the presence of seasonal heteroskedasticity, and use of model comparison statistics (AIC) to compare the models and to search...

cant. To the best of our knowledge, the present study is the first to systematically investigate interindividual seasonal variations of CRP in several large populations. In two studies, seasonal variation of CRP was investigated on an intraindividual basis. Woodhouse et al. (2 ) reported higher CRP concentrations in winter with a peak in March, and Crawford et al. (13 ) found a significant seas...

Altimeter sea surface height (SSH) fields are analyzed to define and discuss the seasonal circulation over the wide continental shelf in the SW Atlantic Ocean (27°-43°S) during 2001-2012. Seasonal variability is low south of the Rio de la Plata (RdlP), where winds and currents remain equatorward for most of the year. Winds and currents in the central and northern parts of our domain are also eq...

background: effect of seasonal changes in human reproduction has been intensively researched. some studies acknowledge influences of seasonal variation on natural conception, while others can not confirm them. the aim of this study was to investigate the effect of seasonal changes on different stages of assisted reproductive technology (art) in tehran. materials and methods: this study was carr...

Monthly price and stock data are used to test the influence of Philippine government buffer-stock programs on seasonal and annual variability of producer and consumer rice prices. The period examined is 1974-1990. NFA stock changes are shown to have had some stabilizing influence on seasonal and annual price changes, but the magnitude is small and not statistically significant.

In the first part of this chapter, we give a review of the relationship of climate and tropical cyclones on various time scales, from intra-seasonal to decadal. The response of tropical cyclone activity to natural modes of variability, such as El Niño-Southern Oscillation and the Madden Julian Oscillation in various regions of the world are discussed. Genesis location, track types and intensity...

Seasonal differences in the manifestation of cardiac death caused by arrhythmia, heart failure or acute myocardial infarction, with peaks during winter months, have been reported. Circadian patterns have also been shown for aortic dissection. A recent large population based study failed to find convincing statistical evidence of seasonal variability for ruptured aneurysms and dissections of the...

A k-means cluster analysis is used to summarize unfiltered daily atmospheric variability at regional-scale over the western Sahel and eastern tropical North Atlantic during the boreal summer season (July—September, JAS) 1961—1998. It employs zonal and meridional regional wind fields at 925, 700 and 200 hPa from the European Centre for Medium Range Weather Forecast Reanalyses. An 8-cluster solut...