2,133 research outputs found
ULYSSES, universal LeptogeneSiS equation solver: Version 2
ULYSSES is a Python package that calculates the baryon asymmetry produced from leptogenesis in the context of a type-I seesaw mechanism. In this release, the new features include code which solves the Boltzmann equations for low-scale leptogenesis; the complete Boltzmann equations for thermal leptogenesis applying proper quantum statistics without assuming kinetic equilibrium of the right-handed neutrinos; and, primordial black hole-induced leptogenesis. ULYSSES version 2 has the added functionality of a pre-provided script for a two-dimensional grid scan of the parameter space. As before, the emphasis of the code is on user flexibility, rapid evaluation and is publicly available at https://github.com/earlyuniverse/ulysses
On the Potts model partition function in an external field
We study the partition function of Potts model in an external (magnetic)
field, and its connections with the zero-field Potts model partition function.
Using a deletion-contraction formulation for the partition function Z for this
model, we show that it can be expanded in terms of the zero-field partition
function. We also show that Z can be written as a sum over the spanning trees,
and the spanning forests, of a graph G. Our results extend to Z the well-known
spanning tree expansion for the zero-field partition function that arises
though its connections with the Tutte polynomial
mHealth versus face-to-face: study protocol for a randomized trial to test a gender-focused intervention for young African American women at risk for HIV in North Carolina
Abstract
Background
Disparities in the prevalence of HIV persist in the southern United States, and young African American women have a disproportionate burden of HIV as compared with young women of other racial/ethnic backgrounds. As a result, engaging young African American women in the HIV care continuum through HIV testing is imperative. This study is designed to reach this key population at risk for HIV. The study seeks to test the efficacy of two formats of a gender-focused, evidence-based, HIV-risk reduction interventionâthe Young Womenâs CoOp (YWC)ârelative to HIV counseling and testing (HCT) among young African American women between the ages of 18 and 25 who use substances and have not recently been tested for HIV.
Methods
Using a seek-and-test framework, this three-arm cross-over randomized trial is being conducted in three county health departments in North Carolina. Each county is assigned to one of three study arms in each cycle: in-person (face-to-face) YWC, mobile Health (mHealth) YWC, or HCT. At study enrollment, participants complete a risk behavior survey via audio computer-assisted self-interview, and drug, alcohol, and pregnancy screening tests, and are then referred to HIV, gonorrhea, and chlamydia testing through their respective health departments. Participants in either of the YWC arms are asked to return approximately 1Â week later to either begin the first of two in-person individual intervention sessions or to pick up the mHealth intervention preloaded on a tablet after a brief introduction to using the app. Participants in all arms are asked to return for a 6-month follow-up and 12-month follow-up, and repeat the survey and biological testing from baseline.
Discussion
The findings from this study will demonstrate which delivery format (mHealth or face-to-face) is efficacious in reducing substance use and sexual risk behaviors. If found to be efficacious, the intervention has potential for wider dissemination and reach.
Trial registration
ClinicalTrials.gov:
NCT02965014
. Registered November 16, 2016
Grassroots Agency: Participation and Conflict in Buenos Aires Shantytowns seen through the Pilot Plan for Villa 7 (1971â1975)
open access articleIn 1971, after more than a decade of national and municipal policies aimed at the top-down removal of shantytowns, the Buenos Aires City Council approved the Plan Piloto para la RelocalizaciĂłn de Villa 7 (Pilot Plan for the Relocation of Shantytown 7; 1971â1975, referred to as the Pilot Plan hereinafter). This particular plan, which resulted in the construction of the housing complex, Barrio Justo SuĂĄrez, endures in the collective memory of Argentines as a landmark project regarding grassroots participation in state housing initiatives addressed at shantytowns. Emerging from a context of a housing shortage for the growing urban poor and intense popular mobilizations during the transition to democracy, the authors of the Pilot Plan sought to empower shantytown residents in novel ways by: 1) maintaining the shantytownâs location as opposed to eradication schemes that relocated the residents elsewhere, 2) formally employing some of the residents for the stage of construction, as opposed to âself-helpâ housing projects in which the residents contributed with unpaid labor, and 3) including them in the urban and architectural design of the of the new housing.
This paper will examine the context in which the Pilot Plan was conceived of as a way of re-assessing the roles of the state, the user, and housing-related professionals, often seen as antagonistic. The paper argues that residentsâ fair participation and state intervention in housing schemes are not necessarily incompatible, and can function in specific social and political contexts through multiactor proposals backed by a political will that prioritizes grassroots agency
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How predation and landscape fragmentation affect vole population dynamics
Background: Microtine species in Fennoscandia display a distinct north-south gradient from regular cycles to stable
populations. The gradient has often been attributed to changes in the interactions between microtines and their predators.
Although the spatial structure of the environment is known to influence predator-prey dynamics of a wide range of species,
it has scarcely been considered in relation to the Fennoscandian gradient. Furthermore, the length of microtine breeding
season also displays a north-south gradient. However, little consideration has been given to its role in shaping or generating
population cycles. Because these factors covary along the gradient it is difficult to distinguish their effects experimentally in
the field. The distinction is here attempted using realistic agent-based modelling.
Methodology/Principal Findings: By using a spatially explicit computer simulation model based on behavioural and
ecological data from the field vole (Microtus agrestis), we generated a number of repeated time series of vole densities
whose mean population size and amplitude were measured. Subsequently, these time series were subjected to statistical
autoregressive modelling, to investigate the effects on vole population dynamics of making predators more specialised, of
altering the breeding season, and increasing the level of habitat fragmentation. We found that fragmentation as well as the
presence of specialist predators are necessary for the occurrence of population cycles. Habitat fragmentation and predator
assembly jointly determined cycle length and amplitude. Length of vole breeding season had little impact on the
oscillations.
Significance: There is good agreement between our results and the experimental work from Fennoscandia, but our results
allow distinction of causation that is hard to unravel in field experiments. We hope our results will help understand the
reasons for cycle gradients observed in other areas. Our results clearly demonstrate the importance of landscape
fragmentation for population cycling and we recommend that the degree of fragmentation be more fully considered in
future analyses of vole dynamics
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Measurement of the [Formula: see text] production cross section using events in the [Formula: see text] final state in pp collisions at [Formula: see text].
The cross section of top quark-antiquark pair production in proton-proton collisions at [Formula: see text] is measured by the CMS experiment at the LHC, using data corresponding to an integrated luminosity of 2.2[Formula: see text]. The measurement is performed by analyzing events in which the final state includes one electron, one muon, and two or more jets, at least one of which is identified as originating from hadronization of a b quark. The measured cross section is [Formula: see text], in agreement with the expectation from the standard model
Clinical Value of Prognostic Instruments to Identify Patients with an Increased Risk for Osteoporotic Fractures: Systematic Review
There is a plethora of evidence available studying the association of risk profiles and the development of osteoporotic fractures. The small number of out-of-sample validations, the large variety of study characteristics, outcomes and follow-up periods impedes from deriving robust summaries and from conclusions regarding the clinical performance of many tools. First and foremost, future activity in this field should aim at reaching a consensus among clinical experts in respect to the existing instruments. Then we call for careful validations and expedient adaptations for local circumstances of the most promising candidates
Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV
A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay
channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7
TeV is presented. The data were collected at the LHC, with the CMS detector,
and correspond to an integrated luminosity of 4.6 inverse femtobarns. No
significant excess is observed above the background expectation, and upper
limits are set on the Higgs boson production cross section. The presence of the
standard model Higgs boson with a mass in the 270-440 GeV range is excluded at
95% confidence level.Comment: Submitted to JHE
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