نتایج جستجو برای: variation trend
تعداد نتایج: 411878 فیلتر نتایج به سال:
Surface ozone (Surface O3)is a secondary pollutant and there are only limited studies on ozone in South India. Studies have revealed a strong correlation between higher ozone levels and warmer days. Surface O3 along with its precursors like NO2, CO and CH4 are being measured at Kanyakumari (8.0780° N, 77.5410° E), TamilNadu, India and in this paper we present the summer time variation of ozone ...
Pertussis is still endemic and the recently resurgence of the disease caused by Bordetella pertussis has been shown in many countries. The polymorphism of the virulence genes of B. pertussis and lack of any information about the allelic variation between the Iranian isolates promotes us to analysis of the genes encoded virulence factors including ptxS1, prn, fim3 and cya to understand the diffe...
Spatio-temporal analyses of yield variability are required to delineate areas of stable yield patterns for application of precision farming techniques. Spatial structure and temporal stability patterns were studied using 19951997 yield data for a 25-ha field located near Story City, Iowa. Corn was grown during 1995-1996, and soybean in 1997. The yield data were collected on nine east-west trans...
Different lines of the fruit fly Drosophila melanogaster show variation in the ability to discriminate between volatiles produced by the yeast Saccharomyces cerevisiae under natural (nitrogen-limiting, YVN) or laboratory (sugar-limiting, YVL) conditions. Previous work in our laboratory uncovered a strong correlation between heightened sensitivity to YVN wild D. melanogaster lines that harbored ...
We address the problem of the factors contributing to a peak color trend of old metal-rich globular cluster (MRGC) populations with mass of their hosts, early-type galaxies and spheroidal subsystems of spiral ones (spheroids). The colormass trend is often converted to a metallicity-mass trend under the assumption that age effects are small or negligible. While direct estimates of the ages of MR...
The problem of estimating underlying trends in time series data arises in a variety of disciplines. In this paper we propose a variation on Hodrick-Prescott (H-P) filtering, a widely used method for trend estimation. The proposed l1 trend filtering method substitutes a sum of absolute values (i.e., an l1-norm) for the sum of squares used in H-P filtering to penalize variations in the estimated ...
The problem of estimating underlying trends in time series data arises in a variety of disciplines. In this paper we propose a variation on Hodrick–Prescott (H-P) filtering, a widely used method for trend estimation. The proposed !1 trend filtering method substitutes a sum of absolute values (i.e., !1 norm) for the sum of squares used in H-P filtering to penalize variations in the estimated tre...
National reference standards (NRSs) for biologics are established through potency estimation by a multicenter joint study of standard materials used in the approval process for national lot release and quality control of vaccines, blood products, and other biologics. In this study, a stability evaluation was conducted to determine whether the potency of NRSs for six blood products was being mai...
This study aims to reveal the runoff variation characteristics of long time series in a karst region, analyse comprehensively its different driving factors, and estimate quantitatively the contribution rates of climate change and human activities to net runoff variation. Liudong river basin, a typical karst watershed in southwest China, is the study site. Statistical methods, such as linear fit...
Rainfall erosivity is commonly used to estimate the probability of soil erosion caused by rainfall. The accurate detection temporal changes in rainfall and identification abrupt trends are important for understanding physical causes variation. In this study, a framework introduced identify time series as follows: (i) significance variation assessed based on Hurst coefficient divided into three ...
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