Browsing Research Articles (Statistics & Population Studies) by Issue Date
Now showing items 21-40 of 162
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Multicolour time series photometry of 2MASS 1207−3932
(Oxford University Press, 2008)Time series photometry in VRI of the young brown dwarf Two-Micron All-Sky Survey (2MASS) J1207334−393254 is presented. Variability in I is insignificant, but amplitudes up to ∼0.2 mag in R, and ∼0.55 mag in V, are seen ... -
Multiple regression of GRB luminosity on light-curve properties
(Oxford University Press, 2009)Statistical relations between the luminosity L of gamma-ray burster (GRBs) and several of their other observable properties have been discovered. Four of these properties are considered here: the spectral lag; a measure ... -
Two new pulsating hot subdwarf stars from the Edinburgh-Cape survey
(Oxford University Press, 2009)We report the discovery of very rapid pulsations in two hot subdwarf stars from the Edinburgh- Cape blue object survey. The short periods, small amplitudes and multiperiodicity establish these stars as members of the ... -
Fitting power-law distributions to data with measurement errors
(Oxford University Press, 2009)If X, which follows a power-law distribution, is observed subject to Gaussian measurement error e, thenX+e is distributed as the convolution of the power-lawand Gaussian distributions. Maximum-likelihood estimation of ... -
Statistical tests for changes in the amplitude, frequency or phase of a sinusoidal variation
(Oxford University Press, 2009)The problem considered is that of testing for small changes over time in the properties of a sinusoidal signal contaminated by noise. Two test statistics are proposed. The first is a frequency domain statistic based on ... -
Correcting CCD photometry of stars for seeing effects
(Oxford Univeristy Press, 2009)Systematic variability in stellarmagnitudes, as derived from profile fitting to CCD images,may in some instances be due to variable seeing. It is suggested that this happens in cases where the stars are unresolved pairs, ... -
Work participation and disabilities in India
(Kamla-Raj Enterprises, 2009)United Nations General Assembly in 1976 proclaimed 1981 as the International Year of the Disable Persons. Persons with disabilities are enthusiastic to overcome the social and economic barriers. In the present paper an ... -
JL 82: a slowly pulsating hot subdwarf star in a close binary system
(Oxford University Press, 2009)JL 82 is a known binary, consisting of an sdB star and a companion which is not directly observable in the optical. Photometric measurements reported in this paper show it to variable with both the binary period (∼0.75 ... -
Confidence intervals for the correlation between the gamma-ray burst peak energy and the associated supernova peak brightness
(Oxford University Press, 2009)A strong correlation between the gamma-ray burster peak energy and the peak luminosity of the associated supernova was discovered by Li for four GRBs. Despite the fact that the formal significance level of the correlation ... -
The Nyquist frequency for time series with slight deviations from regular spacing
(Oxford University Press, 2009)The paper is based on the notion that the Nyquist frequency νN is a symmetry point of the periodogram of a time series: the power spectrum at frequencies above νN is a mirror image of that below νN. Koen showed that the ... -
Is there evolution in the infrared Tully–Fisher relation? Comparing two linear regressions
(Oxford University Press, 2009)In a recent paper, Puech and co-workers compared K-band Tully–Fisher relations derived for nearby and distant galaxies, respectively. They concluded that the two relations differ, and deduced that there is evolution in ... -
Correlates of infant and child mortality in Ethiopia 2005
(University of the Western Cape, 2010)INTRODUCTION: Risk of mortality prevails for children with shorter birth interval since their mothers are likely to have poor health. AIM: The aim of the study is to determine the indirect estimation of infant and child ... -
Predicting gamma-ray burster redshifts from their prompt emission properties
(Oxford University Press, 2010)This paper presents a study of the relation between gamma-ray burster redshift and several of its prompt emission properties (spectral lag, light curve variability, peak energy, rise time and the peak bolometric flux ... -
Two new variable sdB stars, HE 0218−3437 and LB 1516
(Oxford University Press, 2010)We present photometry which shows that two known hot subdwarf stars, HE 0218−3437 and LB 1516, are variable. LB 1516 exhibits several frequencies in the range 12–25 cycles d−1 (periods of about 1–2 h) with amplitudes ... -
UBV(RI)C JHK observations of Hipparcos-selected nearby stars
(Oxford University Press, 2010)We present homogeneous, standardized UBV(RI)C photometry for over 700 nearby stars selected on the basis of Hipparcos parallaxes. Additionally, we list JHK photometry for about half of these stars, as well as L photometry ... -
HE 0230−4323 revisited: a new rapidly pulsating sdB star
(Oxford University Press, 2010)HE 0230−4323 is a hot sdB star in a binary system. An earlier work demonstrated that the light curve of the system shows a strong (∼4 per cent) reflection effect and also appears to exhibit photometric variations of the ... -
Simulation of Y-chromosomal haplotype data
(Elsevier, 2010)The non-recombining nature of the Y-chromosome determines the non-independence of alleles between loci. The evolution of short tandem repeat (STR) loci in the Y-chromosome is the result of different factors such as ... -
The “four sigma” limit for significant periodicities
(Springer Verlag, 2010)Most of the pulsations which have been observed in sdB stars have very low amplitudes. Detection of modes from photometric observations is usually performed by noting the most prominent peaks in a periodogram or, ... -
PG 0907+123 and JL 194: slowly pulsating hot subdwarf stars
(Oxford University Press, 2010)Multicolour time-series photometry of two newly discovered slowly pulsating sdB stars (V1093 Her stars, also known as PG 1716 stars) is described. Both stars are fairly bright and appear, from the limited amount of data, ... -
On the nature of the variable star UNSW-V-760
(Oxford University Press, 2011)The results of multicolour photometric monitoring over several nights of the probable X-ray source UNSW-V-760 are presented. Drawing on both present and past observations, it is shown that the star is multiperiodic and ...
