11,100 research outputs found
Euler Obstruction and Defects of Functions on Singular Varieties
Several authors have proved Lefschetz type formulae for the local Euler
obstruction. In particular, a result of this type is proved in [BLS].The
formula proved in that paper turns out to be equivalent to saying that the
local Euler obstruction, as a constructible function, satisfies the local Euler
condition (in bivariant theory) with respect to general linear forms.
The purpose of this work is to understand what prevents the local Euler
obstruction of satisfying the local Euler condition with respect to functions
which are singular at the considered point. This is measured by an invariant
(or ``defect'') of such functions that we define below. We give an
interpretation of this defect in terms of vanishing cycles, which allows us to
calculate it algebraically. When the function has an isolated singularity, our
invariant can be defined geometrically, via obstruction theory. We notice that
this invariant unifies the usual concepts of {\it the Milnor number} of a
function and of the {\it local Euler obstruction} of an analytic set.Comment: 18 page
The first experimental flight package of an advanced telemetry system with adaptive capability Technical summary report, 1 Jul. 1963 - 15 Feb. 1965
Mechanical design, and environmental and functional testing of advanced telemetry system flight package with adaptive capabilit
Test of nuclear level density inputs for Hauser-Feshbach model calculations
The energy spectra of neutrons, protons, and alpha-particles have been
measured from the d+59Co and 3He+58Fe reactions leading to the same compound
nucleus, 61$Ni. The experimental cross sections have been compared to
Hauser-Feshbach model calculations using different input level density models.
None of them have been found to agree with experiment. It manifests the serious
problem with available level density parameterizations especially those based
on neutron resonance spacings and density of discrete levels. New level
densities and corresponding Fermi-gas parameters have been obtained for
reaction product nuclei such as 60Ni,60Co, and 57Fe
Young people, sexuality and the age of pornography
Recently interest into the effects of pornography on children and young people’s sexual development has increased leading to an increase in studies in the area, laws being changed and public concern growing. This paper aims to recap these findings including more recent studies carried out in the UK. The literature shows links between viewing pornography and sexually explicit material and young people’s attitudes and behaviours. This suggests that young people’s sexuality is affected by sexual imagery and that this influences children and young people’s sexual attitudes and behaviours. The impact is contingent on the young person’s support network, social learning and other demographic factors, not least gender which has been consistently found to be significant. Recent studies have found changes in sexual practices of young people which are attributed to viewing pornography such as an increase in anal sex and casual attitudes to consent. Links between porn use and sexual coercion have also been found. How and in what ways children and young people are affected by such imagery - and what can be done to reduce the negative impact on young people is debated in the light of the gaps in the literature and the issues with the existing literature. Further need for study is discussed
Sources of Streptococcus dysgalactiae in English and Welsh sheep flocks affected by infectious arthritis (joint ill)
Literature Review: The Impact of Major Sporting Events
The Sports Development Impact of the Manchester 2002 Commonwealth Games: Initial Baseline ResearchThis report consists of a literature review of studies of previous major sporting events. It is intended as a general guide to the kind of studies carried out with a view to informing UK Sport about their intended research programme into the sports development impact of the Manchester
Commonwealth Games in 2002.UK Spor
Digital receiver study and implementation
Computer software was developed which makes it possible to use any general purpose computer with A/D conversion capability as a PSK receiver for low data rate telemetry processing. Carrier tracking, bit synchronization, and matched filter detection are all performed digitally. To aid in the implementation of optimum computer processors, a study of general digital processing techniques was performed which emphasized various techniques for digitizing general analog systems. In particular, the phase-locked loop was extensively analyzed as a typical non-linear communication element. Bayesian estimation techniques for PSK demodulation were studied. A hardware implementation of the digital Costas loop was developed
Hemiparasitic plant impacts animal and plant communities across four trophic levels
1.Understanding the impact of species on community structure is a fundamental question in ecology. There is a growing body of evidence that suggests that both sub-dominant species and parasites can have a disproportionately large impact.
2.Here we report the impacts of an organism that is both subdominant and parasitic, the hemiparasite Rhinanthus minor. Whilst the impact of parasitic angiosperms on their hosts and, to a lesser degree, co-existing plant species, have been well characterized, much less is known about their impacts on higher trophic levels.
3.We experimentally manipulated field densities of the hemiparasite Rhinanthus minor in a species rich grassland, comparing the plant and invertebrate communities in plots where it was removed, at natural densities or at enhanced densities.
4.Plots with natural and enhanced densities of R. minor had lower plant biomass than plots without the hemiparasite, but enhanced densities almost doubled the abundance of invertebrates within the plots across all trophic levels, with effects evident in herbivores, predators and detritivores.
5.The hemiparasite R. minor, despite being a sub-dominant and transient component within plant communities that it inhabits, has profound effects on four different trophic levels. These effects persist beyond the life of the hemiparasite,
emphasizing its role as a keystone species in grassland communitie
Subaru Suprime-Cam Weak Lensing Survey over 33 deg^2
Under the currently popular CDM model, mass plays the major role in evolution of large scale structure of the universe. In order to examine the paradigm based on observations, it ould be ideal to use purely mass selected object catalog. Weak lensing surveys enable a blind search of cluster scale objects, and thus could provide such catalogs. We are working on a weak lensing survey using Subaru Prime Focus Camera (Suprime-Cam). In this note, we introduce our survey strategy, and the status as well as the performance of Suprime-Cam as a weak lensing surveyor
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