1,019 research outputs found
Positive operator valued measures covariant with respect to an irreducible representation
Given an irreducible representation of a group G, we show that all the
covariant positive operator valued measures based on G/Z, where Z is a central
subgroup, are described by trace class, trace one positive operators.Comment: 9 pages, Latex2
Mirror displacement energies and neutron skins
A gross estimate of the neutron skin [0.80(5) fm] is extracted from
experimental proton radii, represented by a four parameter fit, and observed
mirror displacement energies (CDE). The calculation of the latter relies on an
accurately derived Coulomb energy and smooth averages of the charge symmetry
breaking potentials constrained to state of the art values. The only free
parameter is the neutron skin itself. The Nolen Schiffer anomaly is reduced to
small deviations (rms=127 keV) that exhibit a secular trend. It is argued that
with state of the art shell model calculations the anomaly should disappear.
Highly accurate fits to proton radii emerge as a fringe benefit.Comment: 4 pages 3 figures, superseeds first part of nucl-th/0104048 Present
is new extended version: 5 pages 4 figures. Explains more clearly the
achievements of the previous on
Indoor air pollution, health and economic well-being
Abstract. Indoor air pollution (IAP) caused by solid fuel use and/or traditional cooking stoves is a global health threat, particularly for women and young children. The WHO World Health Report 2002 estimates that IAP is responsible for 2.7% of the loss of disability adjusted life years (DALYs) worldwide and 3.7% in highmortality developing countries. Despite the magnitude of this problem, social scientists have only recently begun to pay closer attention to this issue and to test strategies for reducing IAP. In this paper, we provide a survey of the current literature on the relationship between indoor air pollution, respiratory health and economic well-being. We then discuss the available evidence on the effectiveness of popular policy prescriptions to reduce IAP within the household
Three-body monopole corrections to the realistic interactions
It is shown that a very simple three-body monopole term can solve practically
all the spectroscopic problems--in the , and shells--that were
hitherto assumed to need drastic revisions of the realistic potentials.Comment: 4 pages, 5figure
Shell Model Description of Isotope Shifts in Calcium
Isotope shifts in the nuclear charge radius of even and odd calcium isotopes
are calculated within the nuclear shell model. The model space includes all
configurations of nucleons in the
orbits. The shell model describes well the energies of the intruder states in
Sc and Ca, as well as the energies of the low-lying and states in
the even Ca isotopes. The characteristic features of the isotope shifts, the
parabolic dependence on and the prominent odd-even staggering, are well
reproduced by the model. These features are related to the partial breakdown of
the shell closure caused by promotion, due to the neutron-proton
interaction, of the shell protons into the shell.Comment: 4 pages, 4 figures include
Preferences and skills of Indian public sector teachers
With a sample of 700 future public sector primary teachers in India, a Discrete Choice Experiment is used to measure job preferences, particularly regarding location. General skills are also tested. Urban origin teachers and women are more averse to remote locations than rural origin teachers and men respectively. Women would require a 26-73 percent increase in salary for moving to a remote location. The results suggest that existing caste and gender quotas can be detrimental for hiring skilled teachers willing to work in remote locations. The most preferred location is home, which supports decentralised hiring, although this could compromise skills
Full shell model calculation of the binding energies of the nuclei
Binding energies and other global properties of nuclei in the middle of the
shell, such as M1, E2 and Gamow-Teller sum rules, have been obtained using
a new Shell Model code (NATHAN) written in quasi-spin formalism and using a
-coupled basis. An extensive comparison is made with the recently
available Shell Model Monte Carlo results using the effective interaction KB3.
The binding energies for -nearly- all the nuclei are compared with
the measured (and extrapolated) results.Comment: 7 page
Whatâs on trial? The making of field experiments in international development
In the last 20Â years, the drive for evidenceâbased policymaking has been coupled with a concurrent push for the use of randomized controlled trials (RCTs) as the âgoldâstandardâ for generating rigorous evidence on whether or not development interventions work. Drawing on content analysis of 63 development RCTs and 4 years of participant observation, I provide a rich description of the diverse set of actors and the transnational organizational effort required to implement development RCTs and maintain their âscientific status.â Particularly, I investigate the boundary work that proponents of RCTsâalso known as randomistasâdo to differentiate the purposes and merits of testing development projects from doing them, as a way to bypass the political and ethical problems presented by adopting the experimental method with foreign aid beneficiaries in poor countries. Although randomistas have been mostly successful in differentiating RCTs from the projects evaluated, I also examine cases where they were not able to do so, as a means to highlight the controversies associated with implementing RCTs in international development.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154964/1/bjos12723_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154964/2/bjos12723.pd
Syzygies in equivariant cohomology for non-abelian Lie groups
We extend the work of Allday-Franz-Puppe on syzygies in equivariant
cohomology from tori to arbitrary compact connected Lie groups G. In
particular, we show that for a compact orientable G-manifold X the analogue of
the Chang-Skjelbred sequence is exact if and only if the equivariant cohomology
of X is reflexive, if and only if the equivariant Poincare pairing for X is
perfect. Along the way we establish that the equivariant cohomology modules
arising from the orbit filtration of X are Cohen-Macaulay. We allow singular
spaces and introduce a Cartan model for their equivariant cohomology. We also
develop a criterion for the finiteness of the number of infinitesimal orbit
types of a G-manifold.Comment: 28 pages; minor change
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