6,387 research outputs found
Angular Momentum Profiles of Warm Dark Matter Halos
We compare the specific angular momentum profiles of virialized dark halos in
cold dark matter (CDM) and warm dark matter (WDM) models using high-resolution
dissipationless simulations. The simulations were initialized using the same
set of modes, except on small scales, where the power was suppressed in WDM
below the filtering length. Remarkably, WDM as well as CDM halos are
well-described by the two-parameter angular momentum profile of Bullock et al.
(2001), even though the halo masses are below the filtering scale of the WDM.
Although the best-fit shape parameters change quantitatively for individual
halos in the two simulations, we find no systematic variation in profile shapes
as a function of the dark matter type. The scatter in shape parameters is
significantly smaller for the WDM halos, suggesting that substructure and/or
merging history plays a role producing scatter about the mean angular momentum
distribution, but that the average angular momentum profiles of halos originate
from larger-scale phenomena or a mechanism associated with the virialization
process. The known mismatch between the angular momentum distributions of dark
halos and disk galaxies is therefore present in WDM as well as CDM models. Our
WDM halos tend to have a less coherent (more misaligned) angular momentum
structure and smaller spin parameters than do their CDM counterparts, although
we caution that this result is based on a small number of halos.Comment: 5 pages, 1 figure, Submitted to ApJ
Search for lepton flavor violating decays of a heavy neutral particle in p-pbar collisions at root(s)=1.8 TeV
We report on a search for a high mass, narrow width particle that decays
directly to e+mu, e+tau, or mu+tau. We use approximately 110 pb^-1 of data
collected with the Collider Detector at Fermilab from 1992 to 1995. No evidence
of lepton flavor violating decays is found. Limits are set on the production
and decay of sneutrinos with R-parity violating interactions.Comment: Figure 2 fixed. Reference 4 fixed. Minor changes to tex
Measurement of Resonance Parameters of Orbitally Excited Narrow B^0 Mesons
We report a measurement of resonance parameters of the orbitally excited
(L=1) narrow B^0 mesons in decays to B^{(*)+}\pi^- using 1.7/fb of data
collected by the CDF II detector at the Fermilab Tevatron. The mass and width
of the B^{*0}_2 state are measured to be m(B^{*0}_2) =
5740.2^{+1.7}_{-1.8}(stat.) ^{+0.9}_{-0.8}(syst.) MeV/c^2 and \Gamma(B^{*0}_2)
= 22.7^{+3.8}_{-3.2}(stat.) ^{+3.2}_{-10.2}(syst.) MeV/c^2. The mass difference
between the B^{*0}_2 and B^0_1 states is measured to be
14.9^{+2.2}_{-2.5}(stat.) ^{+1.2}_{-1.4}(syst.) MeV/c^2, resulting in a B^0_1
mass of 5725.3^{+1.6}_{-2.2}(stat.) ^{+1.4}_{-1.5}(syst.) MeV/c^2. This is
currently the most precise measurement of the masses of these states and the
first measurement of the B^{*0}_2 width.Comment: 7 pages, 1 figure, 1 table. Submitted to Phys.Rev.Let
Measurement of the fraction of t-tbar production via gluon-gluon fusion in p-pbar collisions at sqrt(s)=1.96 TeV
We present a measurement of the ratio of t-tbar production cross section via
gluon-gluon fusion to the total t-tbar production cross section in p-pbar
collisions at sqrt{s}=1.96 TeV at the Tevatron. Using a data sample with an
integrated luminosity of 955/pb recorded by the CDF II detector at Fermilab, we
select events based on the t-tbar decay to lepton+jets. Using an artificial
neural network technique we discriminate between t-tbar events produced via
q-qbar annihilation and gluon-gluon fusion, and find
Cf=(gg->ttbar)/(pp->ttbar)<0.33 at the 68% confidence level. This result is
combined with a previous measurement to obtain the most precise measurement of
this quantity, Cf=0.07+0.15-0.07.Comment: submitted to Phys. Rev.
A dependent nominal type theory
Nominal abstract syntax is an approach to representing names and binding
pioneered by Gabbay and Pitts. So far nominal techniques have mostly been
studied using classical logic or model theory, not type theory. Nominal
extensions to simple, dependent and ML-like polymorphic languages have been
studied, but decidability and normalization results have only been established
for simple nominal type theories. We present a LF-style dependent type theory
extended with name-abstraction types, prove soundness and decidability of
beta-eta-equivalence checking, discuss adequacy and canonical forms via an
example, and discuss extensions such as dependently-typed recursion and
induction principles
Non-Deterministic Kleene Coalgebras
In this paper, we present a systematic way of deriving (1) languages of
(generalised) regular expressions, and (2) sound and complete axiomatizations
thereof, for a wide variety of systems. This generalizes both the results of
Kleene (on regular languages and deterministic finite automata) and Milner (on
regular behaviours and finite labelled transition systems), and includes many
other systems such as Mealy and Moore machines
Typing Copyless Message Passing
We present a calculus that models a form of process interaction based on
copyless message passing, in the style of Singularity OS. The calculus is
equipped with a type system ensuring that well-typed processes are free from
memory faults, memory leaks, and communication errors. The type system is
essentially linear, but we show that linearity alone is inadequate, because it
leaves room for scenarios where well-typed processes leak significant amounts
of memory. We address these problems basing the type system upon an original
variant of session types.Comment: 50 page
Health promotion co-existing in a high-security prison context : a documentary analysis
Purpose: There is interest in promoting health in prison from governmental levels, but, to date, understanding how best to do this is unclear. This paper argues that nuanced understanding of context is required in order to understand health promotion in prison and examines the potential for empowerment, a cornerstone of health promotion practice, in high-security prison establishments. Design/methodology/approach: Independent prison inspections, conducted by Her Majesty’s Inspectorate of Prisons for England and Wales (HMIP), form a critical element in how prisons are assessed. Documentary analysis was undertaken on all eight high-security prison reports using framework analysis. Findings: Analysis revealed elements of prison life which were disempowering and antithetical to health promotion. While security imperatives were paramount, there were examples where this was disproportionate and disempowered individuals. The data shows examples where, even in these high-security contexts, empowerment can be fostered. These were exemplified in relation to peer approaches designed to improve health and where prisoners felt part of democratic processes where they could influence change. Practical implications: Both in the UK and internationally, there is a growing rhetoric for delivering effective health promotion interventions in prison, but limited understanding about how to operationalise this. This paper gives insight into how this could be done in a high-security prison environment. Originality/value: This is the first paper which looks at the potential for health promotion to be embedded in high-security prisons. It demonstrates features of prison life which act to disempower and also support individuals to take greater control over their health
Is self-assessment in religious education unique?
This paper addresses the question: is self-assessment in religious education unique? It first presents an overview of some challenges for assessment from subject differences, and then reviews the generic literature on self-assessment. It builds on earlier empirical research on self-assessment in religious education, carried out in an English state secondary school (Fancourt 2010); this was used to propose a variant of self-assessment which is tailored to the demands of religious education – reflexive self-assessment. Its implications for more general understandings of the relationship between subject pedagogy and self-assessment are discussed, especially the recognition of values not only in religious education but in other subjects too, reinforcing the need to develop subject-specific variants of self-assessment that reflect the breadth of learning outcomes
Liza Smile! Smile! Smile! / music by Arthur Gillespie; words by James M. Reilly
Cover: photo of Miss Annie Kenwick; Publisher: Reilly and Co. (Albany)https://egrove.olemiss.edu/sharris_b/1023/thumbnail.jp
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