3,760 research outputs found
The Gaugephobic Higgs
We present a class of models that contains Randall-Sundrum and Higgsless
models as limiting cases. Over a wide range of the parameter space WW
scattering is mainly unitarized by Kaluza-Klein partners of the W and Z, and
the Higgs particle has suppressed couplings to the gauge bosons. Such a
gaugephobic Higgs can be significantly lighter than the 114 GeV LEP bound for a
standard Higgs, or heavier than the theoretical upper bound. These models
predict a suppressed single top production rate and unconventional Higgs
phenomenology at the LHC: the Higgs production rates will be suppressed and the
Higgs branching fractions modified. However, the more difficult the Higgs
search at the LHC is, the easier the search for other light resonances (like
Z', W', t', exotic fermions) will be.Comment: 20 pages, 3 figure
Modelling the spatial distribution of five natural hazards in the context of the WHO/EMRO Atlas of Disaster Risk as a step towards the reduction of the health impact related to disasters
BACKGROUND: Reducing the potential for large scale loss of life, large numbers of casualties, and widespread displacement of populations that can result from natural disasters is a difficult challenge for the individuals, communities and governments that need to respond to such events. While it is extremely difficult, if not impossible, to predict the occurrence of most natural hazards; it is possible to take action before emergency events happen to plan for their occurrence when possible and to mitigate their potential effects. In this context, an Atlas of Disaster Risk is under development for the 21 Member States that constitute the World Health Organization's (WHO) Eastern Mediterranean (EM) Region and the West Bank and Gaza Strip territory. METHODS AND RESULTS: This paper describes the Geographic Information System (GIS) based methods that have been used in order to create the first volume of the Atlas which looks at the spatial distribution of 5 natural hazards (flood, landslide, wind speed, heat and seismic hazard). It also presents the results obtained through the application of these methods on a set of countries part of the EM Region before illustrating how this type of information can be aggregated for decision making. DISCUSSION AND CONCLUSION: The methods presented in this paper aim at providing a new set of tools for GIS practitioners to refine their analytical capabilities when examining natural hazards, and at the same time allowing users to create more specific and meaningful local analyses. The maps resulting from the application of these methods provides decision makers with information to strengthen their disaster management capacity. It also represents the basis for the reflection that needs to take place regarding populations' vulnerability towards natural hazards from a health perspective
Resonant CP Violation in Higgs Radiation at e^+e^- Linear Collider
We study resonant CP violation in the Higgsstrahlung process e^+e^- ->
H_{1,2,3} (Z -> e^+e^-, \mu^+\mu^-) and subsequent decays H_{1,2,3} -> b
\bar{b}, \tau^-\tau^+, in the MSSM with Higgs-sector CP violation induced by
radiative corrections. At a high-energy e^+e^- linear collider, the recoil-mass
method enables one to determine the invariant mass of a fermion pair produced
by Higgs decays with a precision as good as 1 GeV. Assuming an integrated
luminosity of 100/fb, we show that the production lineshape of a coupled system
of neutral Higgs bosons decaying into b\bar{b} quarks is sensitive to the
CP-violating parameters. When the Higgs bosons decay into \tau^-\tau^+, two CP
asymmetries can be defined using the longitudinal and transverse polarizations
of the tau leptons. Taking into account the constraints from electric dipole
moments, we find that these CP asymmetries can be as large as 80 %, in a
tri-mixing scenario where all three neutral Higgs states of the MSSM are nearly
degenerate and mix significantly.Comment: 22 pages, 8 figures, to appear in Phys. Rev.
Ambulatory arterial stiffness index, mortality, and adverse cardiovascular outcomes; Systematic review and meta-analysis.
The ambulatory arterial stiffness index (AASI) is a novel measure of both blood pressure (BP) variability and arterial stiffness. This systematic review and meta-analysis was designed to evaluate the strength of the association between AASI and mortality and major adverse cardiovascular events (MACE). PubMed, Scopus, CINAHL, Google Scholar. and the Cochrane library were searched for relevant studies to July 31, 2023. Two investigators independently extracted data. The Newcastle-Ottawa Scale (NOS) was used to assess the quality of all included articles. The relationship between baseline AASI and outcomes were examined using relative risk (RR) ratios with 95% confidence intervals (CI) with RevMan web. Thirteen studies were included and representing 28 855 adult patients who were followed up from 2.2 to 15.2 years. A 1-standard deviation (1-SD) increase in AASI was associated with a significant increase in all-cause death (RR 1.12; 95% CI: 0.95-1.32), stroke (RR 1.25; 95% CI: 1.09-1.44), and MACE (RR 1.07; 95% CI: 1.01-1.13; [I2 Â =Â 32%]). Higher dichotomized AASI (above vs. below researcher defined cut-offs) was associated with a significant increase in all-cause mortality (RR 1.19; 95% CI: 1.06-1.32), cardiovascular death (RR 1.29; 95% CI: 1.14-1.46), stroke (RR 1.57; 95% CI: 1.33-1.85), and MACE (RR1.29; 95% CI: 1.16-1.44). There was a significant risk of bias in more than 50% of studies with no evidence of significant publication bias. Higher AASI is associated with an increased risk of all-cause and cardiovascular death, stroke, and MACE. Further high-quality studies are warranted to determine reproducible AASI cut-offs to enhance its clinical risk precision
Next-to-leading order corrections to Wt production and decay
We present the results of a next-to-leading order calculation of Wt
production, including the decays of both the top quark and the W boson. The
effects of radiation in the decay of the top quark are also included. The
separation of diagrams which appear in the real corrections, into singly- and
doubly-resonant contributions, is performed using a b-jet veto which is
motivated by the use of the bottom quark distribution function. We find that,
for a choice of scale which is suitable for this approach, the QCD corrections
are very mild and only change the cross section by up to 10% at the LHC,
depending on the severity of the b-jet veto. When further cuts are applied,
applicable for a Higgs boson search in the H->WW channel, we find that the
radiative effects greatly decrease the number of background events expected
from this process. In addition, the shapes of relevant distributions can be
significantly changed at next-to-leading order.Comment: 31 pages, 12 figure
Association between non-acute traumatic injury (TI) and heart rate variability (HRV) in adults: A systematic review protocol.
Heart Rate Variability (HRV) is an indirect measure of autonomic function. Attenuated HRV is linked to worsening health outcomes including Major Adverse Cardiovascular Events (MACE). The relationship between traumatic injury (TI) and HRV has been limitedly studied. This research protocol has been designed to conduct a systematic review of the existing evidence on the association between non-acute TI and HRV in adults. Four electronic bibliographic databases (Web of Science, CINAHL, Medline, and Scopus) will be searched. The studies on non-acute (>7 days post injury) TI and HRV in adults will be included, followed by title-abstract screening by two reviewers independently. The quality and risk of bias of the included studies will be assessed using Axis and a six-item Risk of Bias Assessment tool for of Non-randomized Studies (RoBANS) respectively. Grading of Recommendations Assessment, Development and Evaluation (GRADE) will assess the quality of evidence. The extracted data will be synthesized using narrative syntheses and a Forest plot with or without meta-analysis- whichever permitted by the pooled data. This will be the first systematic review to examine the relationship between generalized TI and HRV in adults. Trial registration: (PROPSERO registration number: CRD: CRD42021298530) https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021298530
CHANGES IN BALANCE AND JOINT POSITION SENSE DURING A 12-DAY HIGH ALTITUDE TREK
The purpose of this study was to investigate changes in postural control and knee joint position sense (KJPS) during a trek to high altitude. Postural control during standing balance and KJPS were measured in 12 participants at sea-level, 3619m, 4600m and 5140m. Total (p = 0.003, d=1.9) and anterior-posterior sway velocity (p= 0.001, d=1.9) during standing balance with eyes open velocity was significantly greater at altitudes of 3619m and 5140m when compared with sea level. Despite a gradual ascent profile, exposure to 3619 m was associated with impairments in postural control. Importantly, these impairments did not worsen at higher altitudes. The present findings should be considered during future trekking expeditions when considering specific strategies to manage impairments in postural control that occur with increasing altitude
A Four-Way Comparison of Cardiac Function with Normobaric Normoxia, Normobaric Hypoxia, Hypobaric Hypoxia and Genuine High Altitude.
There has been considerable debate as to whether different modalities of simulated hypoxia induce similar cardiac responses.This was a prospective observational study of 14 healthy subjects aged 22-35 years. Echocardiography was performed at rest and at 15 and 120 minutes following two hours exercise under normobaric normoxia (NN) and under similar PiO2 following genuine high altitude (GHA) at 3,375m, normobaric hypoxia (NH) and hypobaric hypoxia (HH) to simulate the equivalent hypoxic stimulus to GHA.All 14 subjects completed the experiment at GHA, 11 at NN, 12 under NH, and 6 under HH. The four groups were similar in age, sex and baseline demographics. At baseline rest right ventricular (RV) systolic pressure (RVSP, p = 0.0002), pulmonary vascular resistance (p = 0.0002) and acute mountain sickness (AMS) scores were higher and the SpO2 lower (p<0.0001) among all three hypoxic groups (GHA, NH and HH) compared with NN. At both 15 minutes and 120 minutes post exercise, AMS scores, Cardiac output, septal S', lateral S', tricuspid S' and A' velocities and RVSP were higher and SpO2 lower with all forms of hypoxia compared with NN. On post-test analysis, among the three hypoxia groups, SpO2 was lower at baseline and 15 minutes post exercise with GHA (89.3±3.4% and 89.3±2.2%) and HH (89.0±3.1 and (89.8±5.0) compared with NH (92.9±1.7 and 93.6±2.5%). The RV Myocardial Performance (Tei) Index and RVSP were significantly higher with HH than NH at 15 and 120 minutes post exercise respectively and tricuspid A' was higher with GHA compared with NH at 15 minutes post exercise.GHA, NH and HH produce similar cardiac adaptations over short duration rest despite lower SpO2 levels with GHA and HH compared with NH. Notable differences emerge following exercise in SpO2, RVSP and RV cardiac function
Prospects of Searches for Gauge Mediated Supersymmetry with h^0 -> {\chi}_1^0 {\chi}_1^0 production in the Time-Delayed Photon + MET Final State at the Tevatron
We propose a search for direct production and decay of the lightest
supersymmetric Higgs boson to two neutralinos in gauge mediated models at the
Fermilab Tevatron. We focus on the final state where each neutralino decays to
photon and light gravitino with a lifetime of order O(ns). In the detector this
will show up as a photon with a time-delayed signature and missing E_T. We
estimate that using the photon timing system at CDF, and the full 10/fb data
sample, that the sensitivity can be within a factor of three in some regions of
parameter space for direct production of the Higgs.Comment: 15 pages, 5 figures, 1 tabl
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