518 research outputs found
Galaxy Zoo : Building the low-mass end of the red sequence with local post-starburst galaxies
We present a study of local post-starburst galaxies (PSGs) using the photometric and spectroscopic observations from the Sloan Digital Sky Survey and the results from the Galaxy Zoo project. We find that the majority of our local PSG population have neither early- nor late-type morphologies but occupy a well-defined space within the colour-stellar mass diagram, most notably, the low-mass end of the 'green valley' below the transition mass thought to be the mass division between low-mass star-forming galaxies and high-mass passively evolving bulge-dominated galaxies. Our analysis suggests that it is likely that local PSGs will quickly transform into 'red', low-mass early-type galaxies as the stellar morphologies of the 'green' PSGs largely resemble that of the early-type galaxies within the same mass range. We propose that the current population of PSGs represents a population of galaxies which is rapidly transitioning between the star-forming and the passively evolving phases. Subsequently, these PSGs will contribute towards the build-up of the low-mass end of the 'red sequence' once the current population of young stars fade and stars are no longer being formed. These results are consistent with the idea of 'downsizing' where the build-up of smaller galaxies occurs at later epochs.Peer reviewe
The anapole moment and nucleon weak interactions
From the recent measurement of parity nonconservation (PNC) in the Cs atom we
have extracted the constant of the nuclear spin dependent electron-nucleon PNC
interaction, ; the anapole moment constant, ; the strength of the PNC proton-nucleus potential, ; the -meson-nucleon interaction constant,
; and the strength of the neutron-nucleus potential, .Comment: Uses RevTex, 12 pages. We have added an explanation of the effect of
finite nuclear siz
Lubricating Bacteria Model for Branching growth of Bacterial Colonies
Various bacterial strains (e.g. strains belonging to the genera Bacillus,
Paenibacillus, Serratia and Salmonella) exhibit colonial branching patterns
during growth on poor semi-solid substrates. These patterns reflect the
bacterial cooperative self-organization. Central part of the cooperation is the
collective formation of lubricant on top of the agar which enables the bacteria
to swim. Hence it provides the colony means to advance towards the food. One
method of modeling the colonial development is via coupled reaction-diffusion
equations which describe the time evolution of the bacterial density and the
concentrations of the relevant chemical fields. This idea has been pursued by a
number of groups. Here we present an additional model which specifically
includes an evolution equation for the lubricant excreted by the bacteria. We
show that when the diffusion of the fluid is governed by nonlinear diffusion
coefficient branching patterns evolves. We study the effect of the rates of
emission and decomposition of the lubricant fluid on the observed patterns. The
results are compared with experimental observations. We also include fields of
chemotactic agents and food chemotaxis and conclude that these features are
needed in order to explain the observations.Comment: 1 latex file, 16 jpeg files, submitted to Phys. Rev.
Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in âs = 7 TeV pp collisions with the ATLAS detector
A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fbâ1 of protonâproton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results
Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC
Measurements of inclusive jet suppression in heavy ion collisions at the LHC
provide direct sensitivity to the physics of jet quenching. In a sample of
lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated
luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with
a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the
transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the
anti-kt algorithm with values for the distance parameter that determines the
nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of
the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp.
Jet production is found to be suppressed by approximately a factor of two in
the 10% most central collisions relative to peripheral collisions. Rcp varies
smoothly with centrality as characterized by the number of participating
nucleons. The observed suppression is only weakly dependent on jet radius and
transverse momentum. These results provide the first direct measurement of
inclusive jet suppression in heavy ion collisions and complement previous
measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables,
submitted to Physics Letters B. All figures including auxiliary figures are
available at
http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02
The burden of injury in China, 1990-2017: findings from the Global Burden of Disease Study 2017
Background A comprehensive evaluation of the burden of injury is an important foundation for selecting and
formulating strategies of injury prevention. We present results from the Global Burden of Diseases, Injuries, and
Risk Factors Study (GBD) 2017 of non-fatal and fatal outcomes of injury at the national and subnational level, and the
changes in burden for key causes of injury over time in China.
Methods Using the methods and results from GBD 2017, we describe the burden of total injury and the key causes of
injury based on the rates of incidence, cause-specific mortality, and disability-adjusted life years (DALYs) in China
estimated using DisMod-MR 2.1. We additionally evaluated these results at the provincial level for the 34 subnational
locations of China in 2017, measured the change of injury burden from 1990 to 2017, and compared age-standardised
DALYs due to injuries at the provincial level against the expected rates based on the Socio-demographic Index (SDI),
a composite measure of development of income per capita, years of education, and total fertility rate.
Findings In 2017, in China, there were 77·1 million (95% uncertainty interval [UI] 72·5â81·6) new cases of injury severe
enough to warrant health care and 733517 deaths (681254â767006) due to injuries. Injuries accounted for 7·0%
(95% UI 6·6â7·2) of total deaths and 10·0% (9·5â10·5) of all-cause DALYs in China. In 2017, there was a three-times
variation in age-standardised injury DALY rates between provinces of China, with the lowest value in Macao and the
highest in Yunnan. Between 1990 and 2017, the age-standardised incidence rate of all injuries increased by 50·6%
(95% UI 46·6â54·6) in China, whereas the age-standardised mortality and DALY rates decreased by 44·3% (41·1â48·9)
and 48·1% (44·6â51·8), respectively. Between 1990 and 2017, all provinces of China experienced a substantial decline in
DALY rates from all injuries ranging from 16·3% (3·1â28·6) in Shanghai and 60·4% (53·7â66·1) in Jiangxi. Agestandardised DALY rates for drowning; injuries from fire, heat and hot substances; adverse effects of medical treatments;
animal contact; environmental heat and cold exposure; self-harm; and executions and police conflict each declined by
more than 60% between 1990 and 2017.
Interpretation Between 1990 and 2017, China experienced a decrease in the age-standardised DALY and mortality
rates due to injury, despite an increase in the age-standardised incidence rate. These trends occurred in all provinces.
The divergent trends in terms of incidence and mortality indicate that with rapid sociodemographic improvements,
the case fatality of injuries has declined, which could be attributed to an improving health-care system but also to a
decreasing severity of injuries over this time period
Interaction of inflammatory cytokines and erythropoeitin in iron metabolism and erythropoiesis in anaemia of chronic disease
In chronic inflammatory conditions increased endogenous release of specific cytokines (TNFα, IL-1, IL-6, IFNγ and others) is presumed. It has been shown that those of monocyte lineage play a key role in cytokine expression and synthesis. This may be associated with changes in iron metabolism and impaired erythropoiesis and may lead to development of anaemia in patients with rheumatoid arthritis. Firstly, increased synthesis of acute phase proteins, like ferritin, during chronic inflammation is proposed as the way by which the toxic effect of iron and thereby the synthesis of free oxy-radicals causing the damage on the affected joints, may be reduced. This is associated with a shift of iron towards the mononuclear phagocyte system which may participate in the development of anaemia of chronic disease. Secondly, an inhibitory action of inflammatory cytokines (TNFα, IL-1), on proliferation and differentiation of erythroid progenitors as well as on synthesis of erythropoietin has been shown, thereby also contributing to anaemia. Finally, chronic inflammation causes multiple, complex disturbances in the delicate physiologic equilibrium of interaction between cytokines and cells (erythroid progenitors, cells of mononuclear phagocyte system and erythropoietin producing cells) leading to development of anaemia of chronic disease (Fig. 1)
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