نتایج جستجو برای: seasonal

تعداد نتایج: 64727  

Journal: :Journal of evolutionary biology 2013
N I Morehouse N Mandon J-P Christides M Body G Bimbard J Casas

Seasonal polyphenisms are widespread in nature, yet the selective pressures responsible for their evolution remain poorly understood. Previous work has largely focussed either on the developmental regulation of seasonal polyphenisms or putative 'top-down' selective pressures such as predation that may have acted to drive phenotypic divergence. Much less is known about the influence of seasonal ...

2016
Wei Lin Jianhua Z. Huang Tucker McElroy

We propose a new seasonal adjustment method based on the regularized singular value decomposition (RSVD) of the matrix obtained by reshaping the seasonal time series data. The method is flexible enough to capture two kinds of seasonality: the fixed seasonality that does not change over time and the time-varying seasonality that varies from one season to another. RSVD represents the time-varying...

In recent years, many studies have been done on forecasting fuzzy time series. First-order fuzzy time series forecasting methods with first-order lagged variables and high-order fuzzy time series forecasting methods with consecutive lagged variables constitute the considerable part of these studies. However, these methods are not effective in forecasting fuzzy time series which contain seasonal...

One of the pillars of epidemiologic research on the long-term health effects of air pollution is to estimate the chronic exposures over space and time. In this study, we aimed to measure the intra-urban ambient carbon monoxide (CO) concentrations within Urmia city in Iran, and to build a model within the geographic information system (GIS) to estimate the annual and seasonal means anywhere with...

Journal: :iranian journal of veterinary research 2012
a.w. qureshi a. tanveer a. maqbool s. niaz

a study was conducted in the northeastern areas of punjab province (pakistan) to analyse the monthlyand seasonal pattern of fasciolosis in buffaloes and its relation to some climatic factors (temperature,humidity, rainfall and pan-evaporation) was also worked out. the faecal samples of buffaloes were collectedfrom april 2003 to march 2005 on a monthly basis from randomly selected areas and anal...

Journal: :JAMDS 2004
Peter T. Ittig

Estimates of a seasonal index in the standard manner (from a moving average) introduce systematic error into the seasonal estimates if a trend is present. This paper shows that a logarithmic modification of the standard moving average procedure will cause it to be consistent with a trend and is an efficient alternative. This paper also compares several other efficient seasonal indexing procedur...

Journal: :Proceedings. Biological sciences 2005
Katia Koelle Mercedes Pascual Md Yunus

Many diverse infectious diseases exhibit seasonal dynamics. Seasonality in disease incidence has been attributed to seasonal changes in pathogen transmission rates, resulting from fluctuations in extrinsic climate factors. Multi-strain infectious diseases with strain-specific seasonal signatures, such as cholera, indicate that a range of seasonal patterns in transmission rates is possible in id...

Journal: :JORS 2003
J. W. Taylor

This paper considers univariate online electricity demand forecasting for lead times from a half-hour-ahead to a day-ahead. A time series of demand recorded at half-hourly intervals contains more than one seasonal pattern. A within-day seasonal cycle is apparent from the similarity of the demand profile from one day to the next, and a within-week seasonal cycle is evident when one compares the ...

1995
ELI TZIPERMAN STEPHEN E. ZEBIAK MARK A. CANE

The mechanisms by which the seasonal cycle in the equatorial Pacific affects ENSO are investigated using the Zebiak and Cane ENSO prediction model. The most dominant seasonal effect is found to be due to the wind divergence field, as determined by the seasonal motion of the ITCZ, through its effect on the atmospheric heating. The next-order seasonal effects are due to the seasonality of the bac...

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