5,750 research outputs found
Evidence of Environmental Quenching at Redshift z ~ 2
We report evidence of environmental quenching among galaxies at redshift ~ 2,
namely the probability that a galaxy quenches its star formation activity is
enhanced in the regions of space in proximity of other quenched, more massive
galaxies. The effect is observed as strong clustering of quiescent galaxies
around quiescent galaxies on angular scales \theta < 20 arcsec, corresponding
to a proper(comoving) scale of 168 (502) kpc at z = 2. The effect is observed
only for quiescent galaxies around other quiescent galaxies; the probability to
find star-forming galaxies around quiescent or around star-forming ones is
consistent with the clustering strength of galaxies of the same mass and at the
same redshift, as observed in dedicated studies of galaxy clustering. The
effect is mass dependent in the sense that the quenching probability is
stronger for galaxies of smaller mass () than for more
massive ones, i.e. it follows the opposite trend with mass relative to
gravitational galaxy clustering. The spatial scale where the effect is observed
suggests these environments are massive halos, in which case the observed
effect would likely be satellite quenching. The effect is also redshift
dependent in that the clustering strength of quiescent galaxies around other
quiescent galaxies at z = 1.6 is ~ 1.7 times larger than that of the galaxies
with the same stellar mass at z = 2.6. This redshift dependence allows for a
crude estimate of the time scale of environmental quenching of low-mass
galaxies, which is in the range 1.5 - 4 Gyr, in broad agreement with other
estimates and with our ideas on satellite quenching.Comment: 12 pages, 9 figures, Accepted for publication in Ap
Probing axion-like particles at the Electron-Ion Collider
The Electron-Ion Collider~(EIC), a forthcoming powerful high-luminosity
facility, represents an exciting opportunity to explore new physics. In this
article, we study the potential of the EIC to probe the coupling between
axion-like particles~(ALPs) and photons in coherent scattering. The ALPs can be
produced via photon fusion and decay back to two photons inside the EIC
detector. In a prompt-decay search, we find that the EIC can set the most
stringent bound for m_a \lesssim 20\,\GeV and probe the effective scales
GeV. In a displaced-vertex search, which requires
adopting an EM calorimeter technology that provides directionality, the EIC
could probe ALPs with m_a \lesssim 1\,\GeV at effective scales \Lambda
\lesssim 10^{7}\,\GeV. Combining the two search strategies, the EIC can probe
a significant portion of unexplored parameter space in the 0.2 < m_a
<20\,\GeV mass range.Comment: 23 pages, 9 figure
A systematic review of air pollution and incidence of out-of-hospital cardiac arrest
Introduction: Studies have linked air pollution with the incidence of acute coronary artery events and cardiovascular mortality but the association with out-of-hospital cardiac arrest (OHCA) is less clear. Aim: To examine the association of air pollution with the occurrence of OHCA.Methods: Electronic bibliographic databases (until February 2013) were searched. Search terms included common air pollutants and OHCA. Studies of patients with implantable cardioverter defibrillators and OHCA not attended by paramedics were excluded. Two independent reviewers (THKT and TAW) identified potential studies. Methodological: quality was assessed by the Newcastle-Ottawa Scale.Results: Of 849 studies, 8 met the selection criteria. Significant associations between particulate matter (PM) exposure (especially PM2.5) and OHCA were found in 5 studies. An increase of OHCA risk ranged from 2.4% to 7% per interquartile increase in average PM exposure on the same day and up to 4 days prior to the event. A large study found ozone increased the risk of OHCA within 3 h prior to the event. The strongest risk OR of 3.8–4.6% per 20 parts per billion ozone increase of the average level was within 2 h prior to the event. Similarly, another study found an increased risk of 18% within 2 days prior to the event.Conclusions: Larger studies have suggested an increased risk of OHCA with air pollution exposure from PM 2.5 and ozone
Physiotherapists implicitly evaluate bending and lifting with a round back as dangerous
© 2018 Elsevier Ltd. Background: Beliefs can be assessed using explicit measures (e.g. questionnaires) that rely on information of which the person is ‘aware’ and willing to disclose. Conversely, implicit measures evaluate beliefs using computer-based tasks that allow reduced time for introspection thus reflecting ‘automatic’ associations. Thus far, physiotherapists’ beliefs about back posture and safety have not been evaluated with implicit measures. Objectives: (1) Evaluate implicit associations between bending lifting back posture (straight-back vs round-back) and safety (safe vs danger); (2) Explore correlations between implicit and explicit measures of beliefs towards vulnerability of the back. Design: Exploratory cross-sectional quantitative study. Methods: 47 musculoskeletal physiotherapists completed explicit measures of fear of movement (TSK-HC), back beliefs (BackPAQDanger) and beliefs related to bending and lifting back posture and safety (BSB). An Implicit Association Test (IAT) was used to assess implicit associations between (i) images of people bending/lifting with a ‘round-back’ or with a ‘straight-back’ posture, and (ii) words representing ‘safety’ and ‘danger’. A one-sample t-test assessed the degree and direction of the sample's IAT score. Cohen's d provided an effect size of the estimated bias. Correlation between IAT and each explicit measure was assessed using Pearson's coefficient. Results: The sample displayed an implicit association between ‘round-back’ and ‘danger’ (µ = 0.213, 95% CI [0.075-0.350], p =.003), with an effect size magnitude of 0.45. There were fair to moderate correlations between IAT and BSB (r = 0.320, 95% CI [0.036-0.556], p =.029) and, IAT and BackPAQDanger (r = 0.413, 95%CI [0.143-0.626], p =.004). Conclusions: Physiotherapists displayed an implicit bias towards bending and lifting with a round-back as dangerous
Combining Hydrological Modeling and Remote Sensing Observations to Enable Data-Driven Decision Making for Devils Lake Flood Mitigation in a Changing Climate
This slide presentation reviews work to combine the hydrological models and remote sensing observations to monitor Devils Lake in North Dakota, to assist in flood damage mitigation. This reports on the use of a distributed rainfall-runoff model, HEC-HMS, to simulate the hydro-dynamics of the lake watershed, and used NASA's remote sensing data, including the TRMM Multi-Satellite Precipitation Analysis (TMPA) and AIRS surface air temperature, to drive the model
Production of activated carbons from waste tyres for low temperature NOx control
Waste tyres were pyrolysed in a bench scale reactor and the product chars were chemically activated with alkali chemical agents, KOH, K2CO3, NaOH and Na2CO3 to produce waste tyre derived activated carbons. The activated carbon products were then examined in terms of their ability to adsorb NOx (NO) at low temperature (25°C) from a simulated industrial process flue gas. This study investigates the influence of surface area and porosity of the carbons produced with the different alkali chemical activating agents on NO capture from the simulated flue gas. The influence of varying the chemical activation conditions on the porous texture and corresponding NO removal from the flue gas was studied. The activated carbon sorbents were characterized in relation to BET surface area, micropore and mesopore volumes and chemical composition. The highest NO removal efficiency for the waste tyre derived activated carbons was ∼75% which was obtained with the adsorbent treated with KOH which correlated with both the highest BET surface area and largest micropore volume. In contrast, the waste tyre derived activated carbons prepared using K2CO3, NaOH and Na2CO3 alkali activating agents appeared to have little influence on NO removal from the flue gases. The results suggest problematic waste tyres, have the potential to be converted to activated carbons with NOx removal efficiency comparable with conventionally produced carbons
A Flexible and Efficient Approach to Missing Transverse Momentum Reconstruction
The article processing charge was funded by the Open Access Publication Fund of Humboldt-Universität zu Berlin.Missing transverse momentum is a crucial observable for physics at hadron colliders, being the only constraint on the kinematics of “invisible” objects such as neutrinos and hypothetical dark matter particles. Computing missing transverse momentum at the highest possible precision, particularly in experiments at the energy frontier, can be a challenging procedure due to ambiguities in the distribution of energy and momentum between many reconstructed particle candidates. This paper describes a novel solution for efficiently encoding information required for the computation of missing transverse momentum given arbitrary selection criteria for the constituent reconstructed objects. Pileup suppression using information from both the calorimeter and the inner detector is an integral component of the reconstruction procedure. Energy calibration and systematic variations are naturally supported. Following this strategy, the ATLAS Collaboration has been able to optimise the use of missing transverse momentum in diverse analyses throughout Runs 2 and 3 of the Large Hadron Collider and for future analyses.Peer Reviewe
Managing healthcare budgets in times of austerity: the role of program budgeting and marginal analysis
Given limited resources, priority setting or choice making will remain a reality at all levels of publicly funded healthcare across countries for many years to come. The pressures may well be even more acute as the impact of the economic crisis of 2008 continues to play out but, even as economies begin to turn around, resources within healthcare will be limited, thus some form of rationing will be required. Over the last few decades, research on healthcare priority setting has focused on methods of implementation as well as on the development of approaches related to fairness and legitimacy and on more technical aspects of decision making including the use of multi-criteria decision analysis. Recently, research has led to better understanding of evaluating priority setting activity including defining ‘success’ and articulating key elements for high performance. This body of research, however, often goes untapped by those charged with making challenging decisions and as such, in line with prevailing public sector incentives, decisions are often reliant on historical allocation patterns and/or political negotiation. These archaic and ineffective approaches not only lead to poor decisions in terms of value for money but further do not reflect basic ethical conditions that can lead to fairness in the decision-making process. The purpose of this paper is to outline a comprehensive approach to priority setting and resource allocation that has been used in different contexts across countries. This will provide decision makers with a single point of access for a basic understanding of relevant tools when faced with having to make difficult decisions about what healthcare services to fund and what not to fund. The paper also addresses several key issues related to priority setting including how health technology assessments can be used, how performance can be improved at a practical level, and what ongoing resource management practice should look like. In terms of future research, one of the most important areas of priority setting that needs further attention is how best to engage public members
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