4,734 research outputs found
On the "Causality Argument" in Bouncing Cosmologies
We exhibit a situation in which cosmological perturbations of astrophysical
relevance propagating through a bounce are affected in a scale-dependent way.
Involving only the evolution of a scalar field in a closed universe described
by general relativity, the model is consistent with causality. Such a specific
counter-example leads to the conclusion that imposing causality is not
sufficient to determine the spectrum of perturbations after a bounce provided
it is known before. We discuss consequences of this result for string motivated
scenarios.Comment: 4 pages, 1 figure, ReVTeX, to appear in Phys. Rev. Let
The process gg -> WW as a background to the Higgs signal at the LHC
The production of W pairs from the one-loop gluon fusion process is studied.
Formulas are presented for the helicity amplitudes keeping the top mass finite,
but all other quark masses zero. The correlations among the leptons coming from
the W bosons are kept. The contribution of this background to the Higgs boson
search in the WW decay mode at the LHC is estimated by applying the cuts
foreseen in experimental searches using the PYTHIA Monte Carlo program.
Kinematic distributions for the final state leptons are compared to those of
the Higgs boson signal and of the q qbar -> WW background. After applying final
cuts, the gg background is found to be large, at the level of 35% of the q qbar
background.The characteristics of the gg background are very similar to those
of the signal. Therefore, an experimental normalization of this background
component appears to be very difficult and the uncertainty must largely be
determined by theory. As a result, the significance of a Higgs signal in the gg
-> H -> WW mode at the LHC is reduced.Comment: 24 pages, 4 figure
Creation of a Scholars Program in Dental Leadership (SPDL) for Dental and Dental Hygiene Students
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/153552/1/jddj0022033720097310tb04805x.pd
World-line Quantisation of a Reciprocally Invariant System
We present the world-line quantisation of a system invariant under the
symmetries of reciprocal relativity (pseudo-unitary transformations on ``phase
space coordinates" which preserve the Minkowski
metric and the symplectic form, and global shifts in these coordinates,
together with coordinate dependent transformations of an additional compact
phase coordinate, ). The action is that of free motion over the
corresponding Weyl-Heisenberg group. Imposition of the first class constraint,
the generator of local time reparametrisations, on physical states enforces
identification of the world-line cosmological constant with a fixed value of
the quadratic Casimir of the quaplectic symmetry group , the semi-direct product of the pseudo-unitary group with
the Weyl-Heisenberg group (the central extension of the global translation
group, with central extension associated to the phase variable ).
The spacetime spectrum of physical states is identified. Even though for an
appropriate range of values the restriction enforced by the cosmological
constant projects out negative norm states from the physical spectrum, leaving
over spin zero states only, the mass-squared spectrum is continuous over the
entire real line and thus includes a tachyonic branch as well
Fentanyl related overdose in Indianapolis: Estimating trends using multilevel Bayesian models
Introduction: The opioid epidemic has been largely attributed to changes in prescribing practices over the past 20 years. Although current overdose trends appear driven by the opioid fentanyl, heroin has remained the focus of overdose fatality assessments. We obtained full toxicology screens on lethal overdose cases in a major US city, allowing more accurate assessment of the time-course of fentanyl-related deaths.
Methods: We used coroner data from Marion County, Indiana comprising 1583 overdose deaths recorded between January 1, 2010 and April 30, 2017. Bayesian multilevel models were fitted to predict likelihood of lethal fentanyl-related overdose using information about the victim's age, race, sex, zip code, and date of death.
Results: Three hundred and seventy-seven (23.8%) overdose deaths contained fentanyl across the seven-year period. Rates rose exponentially over time, beginning well below 15% from 2010 through 2013 before rising to approximately 50% by 2017. At the beginning of the study period, rates of fentanyl overdose were lowest among Black persons but increased more rapidly, eventually surpassing Whites. Currently, White females may be at particularly low risk of fentanyl overdose and Black females at high risk. Rates were highest for younger and middle-aged groups. Over time, fentanyl was more likely detected without the presence of other opioids.
Conclusions: Fentanyl has increasingly been detected in fatal overdose deaths in Marion County. Policy and program responses must focus on education for those at highest risk of fentanyl exposure and death. These responses should also be tailored to meet the unique needs of high-risk demographics.This publication was supported by the Grant Number, 5 NU17CE002721-02, funded by the Centers for Disease Control and Prevention. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the Centers for Disease Control and Prevention or the Department of Health and Human Services
Prenatal factors contribute to the emergence of kwoshiorkor or marasmus in severe undernutrition: evidence for the predictive adaptation model
Severe acute malnutrition in childhood manifests as oedematous (kwashiorkor, marasmic kwashiorkor) and non-oedematous (marasmus) syndromes with very different prognoses. Kwashiorkor differs from marasmus in the patterns of protein, amino acid and lipid metabolism when patients are acutely ill as well as after rehabilitation to ideal weight for height. Metabolic patterns among marasmic patients define them as metabolically thrifty, while kwashiorkor patients function as metabolically profligate. Such differences might underlie syndromic presentation and prognosis. However, no fundamental explanation exists for these differences in metabolism, nor clinical pictures, given similar exposures to undernutrition. We hypothesized that different developmental trajectories underlie these clinical-metabolic phenotypes: if so this would be strong evidence in support of predictive adaptation model of developmental plasticity
How behavioral economics can help to avoid âThe last mile problemâ in whole genome sequencing
Editorial summary Failure to consider lessons from behavioral economics in the case of whole genome sequencing may cause us to run into the âlast mile problemâ - the failure to integrate newly developed technology, on which billions of dollars have been invested, into society in a way that improves human behavior and decision-making
Lithium in strong magnetic fields
The electronic structure of the lithium atom in a strong magnetic field 0 <=
gamma <= 10 is investigated. Our computational approach is a full configuration
interaction method based on a set of anisotropic Gaussian orbitals that is
nonlinearly optimized for each field strength. Accurate results for the total
energies and one-electron ionization energies for the ground and several
excited states for each of the symmetries ^20^+, ^2(-1)^+, ^4(-1)^+, ^4(-1)^-,
^2(-2)^+, ^4(-2)^+, are presented. The behaviour of these energies
as a function of the field strength is discussed and classified. Transition
wave lengths for linear and circular polarized transitions are presented as
well.Comment: 12 pages, 13 figures, accepted for publication in Phys. Rev.
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Patterned remittances enhance womenâs health-related autonomy
The consequences for women âleft behindâ by virtue of temporary male migration are known to be mixed. On one hand, concomitant changes in fertility, female labor force participation, and social norms are often associated with increased independence for women. On the other hand, women left behind can be vulnerable to increased dependency on members of their husbandsâ family, or face limited access to social institutions. These shifts in womenâs capacity for decision-making can have important implications for their health and well-being. Focusing on the state of Kerala in southern India, we examine the conditions under which the remittances that migrants send home have an impact on the health of women left behind. Specifically, we assess the extent to which the timing of remittance sending can support womenâs autonomy, and hence improve their autonomous healthcare decision-making and mobility to health facilities. We use evidence from migrant households in Kerala, a region deeply engrained in the world labor migration system for over five decades. Analysis is conducted with representative household survey data from the 2016 wave of the Kerala Migration Study (KMS), and paired with in-depth qualitative interviews with women in Kerala whose husbands and other family members have migrated to the Gulf. We show that the positive effect of remittances on womenâs autonomy manifests primarily through the timing of remittance receipt, not the amount of money remitted. Those who receive regular remittances experience more gains in autonomy, as compared to those receiving remittances at irregular intervals, net of amount remitted. This finding challenges the usual emphasis on remittance volume as the driving factor of social and behavioral change in sending communities. Analytical efforts should be refocused on the social-interactional component of remittance sending, and how these interactions can impact womenâs health and autonomy
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