53,801 research outputs found
Mother-young recognition in an ungulate hider species: A unidirectional process
This version is the final, definitive version of this article. MotherāYoung Recognition in an Ungulate Hider Species: A Unidirectional Process.
Marco V. G. Torriani, Elisabetta Vannoni, and Alan G. McElligott
The American Naturalist , Vol. 168, No. 3 (September 2006), pp. 412-420
Published by: The University of Chicago Press for The American Society of Naturalists
Article DOI: 10.1086/50697
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Underestimating Internal Variability Leads to Narrow Estimates of Climate System Properties
Probabilistic estimates of climate system properties often rely on the comparison of model simulations to observed temperature records and an estimate of the internal climate variability. In this study, we investigate the sensitivity of probability distributions for climate system properties in the Massachusetts Institute of Technology Earth System Model to the internal variability estimate. In particular, we derive probability distributions using the internal variability extracted from 25 different Coupled Model Intercomparison Project Phase 5 models. We further test the sensitivity by pooling variability estimates from models with similar characteristics. We find the distributions to be highly sensitive when estimating the internal variability from a single model. When merging the variability estimates across multiple models, the distributions tend to converge to a wider distribution for all properties. This suggests that using a single model to approximate the internal climate variability produces distributions that are too narrow and do not fully represent the uncertainty in the climate system property estimates
Correction: assortative mating in fallow deer reduces the strength of sexual selection.
PMCID: PMC3182158
This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.This article corrects this one:
PLoS One. 2011; 6(4): e18533. doi:10.1371/journal.pone.0018533[This corrects the article on p. e18533 in vol. 6.]
Digitalisasi Masyarakat: Menilik Kekuatan Dan Kelemahan Dinamika Era Informasi Digital Dan Masyarakat Informasi
Some adagium which have been told by modern communications growth observer show that information become one of the vital element in society. Information become a fundamental requirement so that can be expressed as the lifeblood that sustains political, social and business decision. As a consequence, society has to expose themself with the growth and new media dynamics and global communications. The rotation in production, consumption and information distribution is faster experienced of and owned by global new society system supported by economic and extention power, global information system network and also contributed by digital technology. This Paper will explain some of alternative discourse to see the excess and weakness of information technologization process which finally instruct the society at digital era
Knowledge and behavior towards voluntary blood donation among students of a tertiary institution in Nigeria
Background: Blood donation is the only way of acquiring blood to meet emergency requirements in cases of road traffic accidents, complications of pregnancy and childbirth, various anemic disorders and surgical emergencies among others. Globally, 80 million units of blood are donated each year, but only two million units are donated in sub-Saharan Africa where the need is enormous. The objective of this study was to determine the behavior of the students of a tertiary institution in Nigeria towards voluntary blood donation.Materials and Methods: This is a descriptive cross-sectional study, which involved students of a tertiary institution in Nigeria. A multistage sampling technique was employed in selecting the participants for this study. A semi-structured self-administered questionnaire was used to collect information on socio-demographic characteristics, knowledge, attitude and factors affecting voluntary blood donation. The data obtained were analyzed using EPI-INFO 2005 software Version 3.3.2.Results: Less than two-thirds (61%) of total respondents had good knowledge of blood donation. More than three quarters (85%) of the respondents had never donated blood. Of the 15% that had donated, only 3% donated voluntarily. Among those that had ever donated, males (57%) were more than females. Many of the donors donated for relatives (57%). The majority of the respondents were compelled to donate because of emergency situations (75%). The reasons why many did not donate were lack of opportunity (45%) due to tight lecture schedule and inadequate knowledge (24%). Gift items such as hematinics, T-shirts and wrist bands (29%) would motivate respondents to donate.Conclusion: The Students’ Union body and other Organizations in the University should include a blood donation drive in their monthly/annual activities. The University authorities, the University health service centre and the Hematology Department of the Teaching hospital should collaborate in promoting voluntary blood donation among the students
Characterizing normal crossing hypersurfaces
The objective of this article is to give an effective algebraic
characterization of normal crossing hypersurfaces in complex manifolds. It is
shown that a hypersurface has normal crossings if and only if it is a free
divisor, has a radical Jacobian ideal and a smooth normalization. Using K.
Saito's theory of free divisors, also a characterization in terms of
logarithmic differential forms and vector fields is found and and finally
another one in terms of the logarithmic residue using recent results of M.
Granger and M. Schulze.Comment: v2: typos fixed, final version to appear in Math. Ann.; 24 pages, 2
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Dynamic screening of a localized hole during photoemission from a metal cluster
Recent advances in attosecond spectroscopy techniques have fueled the
interest in the theoretical description of electronic processes taking place in
the subfemtosecond time scale. Here we study the coupled dynamic screening of a
localized hole and a photoelectron emitted from a metal cluster using a
semi-classical model. Electron density dynamics in the cluster is calculated
with Time-Dependent Density Functional Theory and the motion of the
photoemitted electron is described classically. We show that the dynamic
screening of the hole by the cluster electrons affects the motion of the
photoemitted electron. At the very beginning of its trajectory, the
photoemitted electron interacts with the cluster electrons that pile up to
screen the hole. Within our model, this gives rise to a significant reduction
of the energy lost by the photoelectron. Thus, this is a velocity dependent
effect that should be accounted for when calculating the average losses
suffered by photoemitted electrons in metals.Comment: 15 pages, 5 figure
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