844 research outputs found
IMAGES I. Strong evolution of galaxy kinematics since z=1
(abbreviated) We present the first results of the ESO large program,
``IMAGES'' which aims at obtaining robust measurements of the kinematics of
distant galaxies using the multi-IFU mode of GIRAFFE on the VLT. 3D
spectroscopy is essential to robustly measure the often distorted kinematics of
distant galaxies (e.g., Flores et al. 2006). We derive the velocity fields and
-maps of 36 galaxies at 0.4<z<0.75 from the kinematics of the [OII]
emission line doublet, and generate a robust technique to identify the nature
of the velocity fields based on the pixels of the highest signal-to-noise
ratios (S/N). We have gathered a unique sample of 63 velocity fields of
emission line galaxies (W0([OII]) > 15 A) at z=0.4-0.75, which are a
representative subsample of the population of M_stellar>1.5x10^{10} M_sun
emission line galaxies in this redshift range, and are largely unaffected by
cosmic variance. Taking into account all galaxies -with or without emission
lines- in that redshift range, we find that at least 41+/-7% of them have
anomalous kinematics, i.e., they are not dynamically relaxed. This includes
26+/-7% of distant galaxies with complex kinematics, i.e., they are not simply
pressure or rotationally supported. Our result implies that galaxy kinematics
are among the most rapidly evolving properties, because locally, only a few
percent of the galaxies in this mass range have complex kinematics.Comment: 17 pages, 6 figures, Accepted by A&
Nonuniversal Effects in the Homogeneous Bose Gas
Effective field theory predicts that the leading nonuniversal effects in the
homogeneous Bose gas arise from the effective range for S-wave scattering and
from an effective three-body contact interaction. We calculate the leading
nonuniversal contributions to the energy density and condensate fraction and
compare the predictions with results from diffusion Monte Carlo calculations by
Giorgini, Boronat, and Casulleras. We give a crude determination of the
strength of the three-body contact interaction for various model potentials.
Accurate determinations could be obtained from diffusion Monte Carlo
calculations of the energy density with higher statistics.Comment: 24 pages, RevTex, 5 ps figures, included with epsf.te
The elementary excitations of the exactly solvable Russian doll BCS model of superconductivity
The recently proposed Russian doll BCS model provides a simple example of a
many body system whose renormalization group analysis reveals the existence of
limit cycles in the running coupling constants of the model. The model was
first studied using RG, mean field and numerical methods showing the Russian
doll scaling of the spectrum, E(n) ~ E0 exp(-l n}, where l is the RG period. In
this paper we use the recently discovered exact solution of this model to study
the low energy spectrum. We find that, in addition to the standard
quasiparticles, the electrons can bind into Cooper pairs that are different
from those forming the condensate and with higher energy. These excited Cooper
pairs can be described by a quantum number Q which appears in the Bethe ansatz
equation and has a RG interpretation.Comment: 36 pages, 12 figure
Scoping the biosecurity risks and appropriate management relating to the freshwater ornamental aquarium trade across northern Australia
The current scoping study provides for a preliminary understanding of the numerous existing and potential pathways for incursions from the aquarium trade into freshwater ecosystems in tropical Australia, encompassing the lands and waterways north of the Tropic of Capricorn. A finding of this desktop project is the lack of consolidated nformation relevant to tropical Australia in terms of biotic incursion of even the better documented taxa (e.g. freshwater fishes) and a lack of information on most taxa in the aquarium trade (e.g. shrimps, molluscs, diseases in the wild). This is the consequence of the extent and scale of the aquatic biosecurity task as well as ad hoc biological sampling, under-resourcing of ecological surveys, monitoring and reporting in the grey or published literature, all of which is compounded by the remoteness of much of tropical northern Australia
On the modification of the Efimov spectrum in a finite cubic box
Three particles with large scattering length display a universal spectrum of
three-body bound states called "Efimov trimers''. We calculate the modification
of the Efimov trimers of three identical bosons in a finite cubic box and
compute the dependence of their energies on the box size using effective field
theory. Previous calculations for positive scattering length that were
perturbative in the finite volume energy shift are extended to arbitrarily
large shifts and negative scattering lengths. The renormalization of the
effective field theory in the finite volume is explicitly verified. Moreover,
we investigate the effects of partial wave mixing and study the behavior of
shallow trimers near the dimer energy. Finally, we provide numerical evidence
for universal scaling of the finite volume corrections.Comment: 21 pages, 8 figures, published versio
Vitamin D deficiency is associated with IL-6 levels and monocyte activation in HIV-infected persons
Immune activation plays a key role in HIV pathogenesis. Markers of inflammation have been associated with vitamin D deficiency in the general population. Studies have also demonstrated associations of vitamin D deficiency with increased risk of HIV progression and death. The relationship between persistent inflammation and immune activation during chronic HIV infection and vitamin D deficiency remains unclear.Cryopreserved specimens were analyzed from 663 participants at the time of enrollment from the Study to Understand the Natural History of HIV/AIDS in the Era of Effective Therapy (SUN Study) from 2004 to 2006. Biomarkers of inflammation, atherosclerosis, and coagulation were measured using enzyme-linked immunosorbent assays (ELISAs) and electrochemiluminescence. 25(OH)D, the stable precursor form of vitamin D, was measured using a radioimmunoassay with levels defined as: normal (≥30ng/mL), insufficient (20-29 ng/mL) and deficient (<20 ng/mL). Monocyte phenotypes were assessed by flow cytometry. Linear and logistic regression models were used to determine statistical associations between biomarkers and vitamin D deficiency.25(OH)D levels were deficient in 251 (38%) participants, insufficient in 222 (34%), and normal in 190 (29%). Patients with vitamin D deficiency, when compared to those with insufficient or normal vitamin D levels, had increased levels of IL-6 (23%; p<0.01), TNF-α (21%, p = 0.03), D-dimer (24%, p = 0.01), higher proportions of CD14dimCD16+ (22%, p<0.01) and CX3CR1+ monocytes (48%; p<0.001) and decreased frequency of CCR2+ monocytes (-3.4%, p<0.001). In fully adjusted models, vitamin D associations with abnormal biomarker levels persisted for IL-6 levels and CX3CR1+ and CCR2+ phenotypes.Vitamin D deficiency is associated with greater inflammation and activated monocyte phenotypes. The role of vitamin D deficiency in persistent immune activation and associated complications during chronic HIV disease should be further evaluated as a possible target for intervention
Comprehensive Peroxidase-Based Hematologic Profiling for The Prediction of 1-Year Myocardial Infarction and Death
Background— Recognition of biological patterns holds promise for improved identification of patients at risk for myocardial infarction (MI) and death. We hypothesized that identifying high- and low-risk patterns from a broad spectrum of hematologic phenotypic data related to leukocyte peroxidase-, erythrocyte- and platelet-related parameters may better predict future cardiovascular risk in stable cardiac patients than traditional risk factors alone. Methods and Results— Stable patients (n=7369) undergoing elective cardiac evaluation at a tertiary care center were enrolled. A model (PEROX) that predicts incident 1-year death and MI was derived from standard clinical data combined with information captured by a high-throughput peroxidase-based hematology analyzer during performance of a complete blood count with differential. The PEROX model was developed using a random sampling of subjects in a derivation cohort (n=5895) and then independently validated in a nonoverlapping validation cohort (n=1474). Twenty-three high-risk (observed in ≥10% of subjects with events) and 24 low-risk (observed in ≥10% of subjects without events) patterns were identified in the derivation cohort. Erythrocyte- and leukocyte (peroxidase)-derived parameters dominated the variables predicting risk of death, whereas variables in MI risk patterns included traditional cardiac risk factors and elements from all blood cell lineages. Within the validation cohort, the PEROX model demonstrated superior prognostic accuracy (78%) for 1-year risk of death or MI compared with traditional risk factors alone (67%). Furthermore, the PEROX model reclassified 23.5% (P\u3c0.001) of patients to different risk categories for death/MI when added to traditional risk factors. Conclusion— Comprehensive pattern recognition of high- and low-risk clusters of clinical, biochemical, and hematologic parameters provided incremental prognostic value in stable patients having elective diagnostic cardiac catheterization for 1-year risks of death and MI
Comprehensive Peroxidase-Based Hematologic Profiling for The Prediction of 1-Year Myocardial Infarction and Death
Background— Recognition of biological patterns holds promise for improved identification of patients at risk for myocardial infarction (MI) and death. We hypothesized that identifying high- and low-risk patterns from a broad spectrum of hematologic phenotypic data related to leukocyte peroxidase-, erythrocyte- and platelet-related parameters may better predict future cardiovascular risk in stable cardiac patients than traditional risk factors alone. Methods and Results— Stable patients (n=7369) undergoing elective cardiac evaluation at a tertiary care center were enrolled. A model (PEROX) that predicts incident 1-year death and MI was derived from standard clinical data combined with information captured by a high-throughput peroxidase-based hematology analyzer during performance of a complete blood count with differential. The PEROX model was developed using a random sampling of subjects in a derivation cohort (n=5895) and then independently validated in a nonoverlapping validation cohort (n=1474). Twenty-three high-risk (observed in ≥10% of subjects with events) and 24 low-risk (observed in ≥10% of subjects without events) patterns were identified in the derivation cohort. Erythrocyte- and leukocyte (peroxidase)-derived parameters dominated the variables predicting risk of death, whereas variables in MI risk patterns included traditional cardiac risk factors and elements from all blood cell lineages. Within the validation cohort, the PEROX model demonstrated superior prognostic accuracy (78%) for 1-year risk of death or MI compared with traditional risk factors alone (67%). Furthermore, the PEROX model reclassified 23.5% (P\u3c0.001) of patients to different risk categories for death/MI when added to traditional risk factors. Conclusion— Comprehensive pattern recognition of high- and low-risk clusters of clinical, biochemical, and hematologic parameters provided incremental prognostic value in stable patients having elective diagnostic cardiac catheterization for 1-year risks of death and MI
Fractionation of lead in soil by isotopic dilution and sequential extraction
‘Reactivity’ or ‘lability’ of lead is difficult to measure using traditional methods. We investigated the use of isotopic dilution with 204Pb to determine metal reactivity in four soils historically contaminated with contrasting sources of Pb, including (i) petrol-derived Pb, (ii) Pb/Zn minespoil, (iii) long-term sewage sludge application and (iv) 19th century urban waste disposal; total soil Pb concentrations ranged from 217 to 13 600 mg kg–1. A post-spike equilibration period of 3 days and suspension in 5.0 × 10–4 M ethylenediaminetetraacetic acid provided reasonably robust conditions for measuring isotopically exchangeable Pb. However, in acidic organic soils a dilute Ca(NO3)2 electrolyte may be preferable to avoid mobilisation of ‘non-labile’ Pb. Results showed that the reactive pool of soil Pb can be a large proportion of the total soil lead content but varies with the original Pb source. A comparison of isotopic exchangeability with the results of a sequential extraction procedure showed that (isotopically) ‘non-labile’ Pb may be broadly equated with ‘residual’ Pb in organic soils. However, in mineral soils the ‘carbonate’ and ‘oxide-bound’ Pb fractions included non-labile forms of Pb. The individual isotopic signatures of labile and non-labile Pb pools suggested that, despite prolonged contact with soil, differences between the lability of the original contaminant and the native soil Pb may remain
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