148 research outputs found
The Imperial IRAS-FSC Redshift Catalogue: luminosity functions, evolution and galaxy bias
We present the luminosity function and selection function of 60 micron
galaxies selected from the Imperial IRAS-FSC Redshift Catalogue (IIFSCz). Three
methods, including the 1/Vmax} and the parametric and non-parametric maximum
likelihood estimator, are used and results agree well with each other. A
density evolution proportional to (1+z)^3.4 or a luminosity evolution exp(1.7
t_L / \tau)$ where t_L is the look-back time is detected in the full sample in
the redshift range [0.02, 0.1], consistent with previous analyses. Of the four
infrared subpopulations, cirrus-type galaxies and M82-type starbursts show
similar evolutionary trends, galaxies with significant AGN contributions show
stronger positive evolution and Arp 220-type starbursts exhibit strong negative
evolution. The dominant subpopulation changes from cirrus-type galaxies to
M82-type starbursts at log (L_60 / L_Sun) ~ 10.3.
In the second half of the paper, we derive the projected two-point spatial
correlation function for galaxies of different infrared template type. The mean
relative bias between cirrus-type galaxies and M82-type starbursts, which
correspond to quiescent galaxies with optically thin interstellar dust and
actively star-forming galaxies respectively, is calculated to be around 1.25.
The relation between current star formation rate (SFR) in star-forming galaxies
and environment is investigated by looking at the the dependence of clustering
on infrared luminosity. We found that M82-type actively star-forming galaxies
show stronger clustering as infrared luminosity / SFR increases. The
correlation between clustering strength and SFR in the local Universe seems to
echo the basic trend seen in star-forming galaxies in the Great Observatories
Origins Deep Survey (GOODS) fields at z ~ 1.Comment: 15 pages, 11 figures, accepted for publication in MNRA
Simulations on High-z Long Gamma-Ray Burst Rate
Since the launch of Swift satellite, the detections of high-z (z>4) long
gamma-ray bursts (LGRBs) have been rapidly growing, even approaching the very
early Universe (the record holder currently is z=8.3). The observed high-z LGRB
rate shows significant excess over that estimated from the star formation
history. We investigate what may be responsible for this high productivity of
GRBs at high-z through Monte Carlo simulations, with effective Swif/BAT trigger
and redshift detection probabilities based on current Swift/BAT sample and
CGRO/BATSE LGRB sample. We compare our simulations to the Swift observations
via log N-log P, peak luminosity (L) and redshift distributions. In the case
that LGRB rate is purely proportional to the star formation rate (SFR), our
simulations poorly reproduce the LGRB rate at z>4, although the simulated log
N-log P distribution is in good agreement with the observed one. Assuming that
the excess of high-z GRB rate is due to the cosmic metallicity evolution or
unknown LGRB rate increase parameterized as (1+z)^delta, we find that although
the two scenarios alone can improve the consistency between our simulations and
observations, incorporation of them gives much better consistency. We get
0.2<epsilon<0.6 and delta<0.6, where epsilon is the metallicity threshold for
the production of LGRBs. The best consistency is obtained with a parameter set
(epsilon, delta)=(~0.4, ~0.4), and BAT might trigger a few LGRBs at z~14. With
increasing detections of GRBs at z>4 (~15% of GRBs in current Swift LGRB sample
based on our simulations), a window for very early Universe is opening by Swift
and up-coming SVOM missions.Comment: 9 pages, including 8 figures and 1 table, one more figure added.
Accepted for publication in MNRA
Diethyl 2-tert-butyl-6,9-dibromo-4,11-dioxo-5,10-dihydro-cis-1H,3H,4H,11H-2-azo-3a,4a,10a,11a-tetraazabenz[f]indeno[2,1,7-ija]azulene-11b,11c-dicarboxylate
In the title compound, C24H29Br2N5O6, a glycoluril derivative, the 1,4-dibromobenzene ring is fused to the seven-membered ring of the glycoluril unit containing two N atoms. The two five-membered rings in the glycoluril unit are approximately planar and the dihedral angle between them is 69.8 (2)°. The six-membered ring containing three N atoms adopts a chair conformation. The crystal packing is stabilized by an intermolecular non-classical C—H⋯O hydrogen bond and a weak C—H⋯π interaction. Both of the ester groups are found to be disordered over two positions. The occupancies of the disordered positions were refined to 0.73(1):0.27(1) and 0.56(1):0.44(1)
Pros and Cons of 19 Sport-Related Concussion Educational Resources in Canada: Avenues for Better Care and Prevention
Objective: The goal of this research was to assess the effectiveness of available concussion educational resources in Canada, the means used to disseminate this knowledge and the impact of these educational resources on players' concussion prevention knowledge.Methods: We assessed concussion knowledge before and after exposure to one or more of 19 resources introduced through a national program aimed to increase awareness and knowledge of concussion. The effectiveness of the mode of delivery was measured by changes in concussion knowledge scores (CKS) between pre and pro scores.Measures: Concussion knowledge scores (CKS) were calculated for pre- and post- exposure to concussion educational resources and used as a measure of both, the effectiveness of each resource as well as the effectiveness of the delivery method. The effectiveness of each educational resource was also measured by the respondents' rating of each concussion educational resource.Results: Respondents in post-survey had higher CKS than those in pre-survey. Two out of the 19 newly developed concussion educational resources were effective in improving the resource users' CKS. Linear regression showed that using more resources further increased CKS. Four out of six modes of delivery enhanced respondents' concussion knowledge.Conclusion: Our findings demonstrate that the newly developed Canadian concussion educational resources were effective at improving users' concussion knowledge. Our data demonstrates that using three or more resources further enhanced the users' concussion knowledge. Future research, however, is critical to assess whether concussion prevention knowledge is sufficient to reduce injuries and factors influencing it
What do “barbarians” eat? Integrating ceramic use-wear and residue analysis in the study of food and society at the margins of Bronze Age China
The Siwa archaeological culture (ca. 3350 and 2650 cal yr BP) has often been associated with the tribes referenced in textual sources as Qiang and Rong: prized captives commonly sacrificed by the Shang and marauding hordes who toppled the Western Zhou dynasty. In early Chinese writings, food plays a key role in accentuating the ‘sino-barbarian’ dichotomy believed to have taken root over 3000 years ago, with the Qiang and Rong described as nomadic pastoralists who consumed more meat than grain and knew little of proper dining etiquette. To date, however, little direct archaeological evidence has allowed us to reconstruct the diet and foodways of the groups who occupied the Loess Plateau during this pivotal period. Here we present the results of the first ceramic use-wear study performed on the Siwa ma’an jars from the site of Zhanqi, combined with the molecular and isotopic characterization of lipid residues from foodcrusts, and evidence from experimental cooking. We report molecular data indicating the preparation of meals composed of millet and ruminant dairy among the Siwa community of Zhanqi. Use-wear analysis shows that Zhanqi community members were sophisticated creators of ceramic equipment, the ma’an cooking pot, which allowed them to prepare a wide number of dishes with limited fuel. These findings support recent isotope studies at Zhanqi as well as nuance the centrality of meat in the Siwa period diet
The Redshift-Space Two Point Correlation Function of ELAIS-S1 Galaxies
We investigate the clustering properties of galaxies in the recently
completed ELAIS-S1 redshift survey through their spatial two point
autocorrelation function. We used a sub-sample of the ELAIS-S1 catalog covering
approximately 4 deg^2 and consisting of 148 objects selected at 15 micron with
a flux >0.5 mJy and redshift z<0.5. We detected a positive signal in the
correlation function that, in the range of separations 1-10 h mpc is well
approximated by a power law with a slope gamma = 1.4 and a correlation length s
=5.4 h mpc. This result is in good agreement with the redshift-space
correlation function measured in more local samples of mid infrared selected
galaxies like the IRAS PSC redshift survey. This suggests a lack of
significant clustering evolution of infrared selected objects out to
that is further confirmed by the consistency found between the correlation
functions measured in a local (z<0.2) and a distant (0.2<z<0.5) subsample of
ELAIS-S1 galaxies. We also confirm that optically selected galaxies in the
local redshift surveys, especially those of the SDSS sample, are significantly
more clustered than infrared objects.Comment: 7 pages, 5 .ps figures, accepted for pubblication in MNRA
Catechol Polymers for pH-Responsive, Targeted Drug Delivery to Cancer Cells
A novel cell-targeting, pH-sensitive polymeric carrier was employed in this study for delivery of the anticancer drug bortezomib (BTZ) to cancer cells. Our strategy is based on facile conjugation of BTZ to catechol-containing polymeric carriers that are designed to be taken up selectively by cancer cells through cell surface receptor-mediated mechanisms. The polymer used as a building block in this study was poly(ethylene glycol), which was chosen for its ability to reduce nonspecific interactions with proteins and cells. The catechol moiety was exploited for its ability to bind and release borate-containing therapeutics such as BTZ in a pH-dependent manner. In acidic environments, such as in cancer tissue or the subcellular endosome, BTZ dissociates from the polymer-bound catechol groups to liberate the free drug, which inhibits proteasome function. A cancer-cell-targeting ligand, biotin, was presented on the polymer carriers to facilitate targeted entry of drug-loaded polymer carriers into cancer cells. Our study demonstrated that the cancer-targeting drug-polymer conjugates dramatically enhanced cellular uptake, proteasome inhibition, and cytotoxicity toward breast carcinoma cells in comparison with nontargeting drug-polymer conjugates. The pH-sensitive catechol-boronate binding mechanism provides a chemoselective approach for controlling the release of BTZ in targeted cancer cells, establishing a concept that may be applied in the future toward other boronic acid-containing therapeutics to treat a broad range of diseases
Predictions for statistical properties of forming spheroidal galaxies
We show that the features of the recent astrophysically motivated model by Granato et al. are fully consistent with the available statistical measurements of galaxies at (sub)millimetre wavelengths. We quantitatively predict the impact of this scenario on near-future cosmological observations dealing with spatial and flux statistical distribution of (sub)millimetre galaxies. We show that the expected angular correlation function of spheroids is compatible with available data. We compute the expected power spectrum of fluctuations due to clustering at the frequencies of the High Frequency Instrument (HFI) on ESA's Planck satellite: the clustering signal is found to be detectable in regions of low interstellar dust emission. A further distinctive prediction of the adopted model is a remarkably high fraction of gravitationally lensed sources at bright millimetre/submillimetre fluxes. In fact, since most spheroids burn at redshift z similar or equal to 2-3 according to the adopted model, gravitational lensing amplifies a significant number of high-z forming spheroidal galaxies, which will be detectable by large-area, shallow surveys at millimetre/submillimetre wavelengths, such as those carried out by Planck/HFI. Allowing for other source populations, we find that the fraction of gravitationally lensed millimetre/submillimetre sources at fluxes > 100 mJy is expected to be up to similar or equal to40 per cent
Omecamtiv mecarbil in chronic heart failure with reduced ejection fraction, GALACTIC‐HF: baseline characteristics and comparison with contemporary clinical trials
Aims:
The safety and efficacy of the novel selective cardiac myosin activator, omecamtiv mecarbil, in patients with heart failure with reduced ejection fraction (HFrEF) is tested in the Global Approach to Lowering Adverse Cardiac outcomes Through Improving Contractility in Heart Failure (GALACTIC‐HF) trial. Here we describe the baseline characteristics of participants in GALACTIC‐HF and how these compare with other contemporary trials.
Methods and Results:
Adults with established HFrEF, New York Heart Association functional class (NYHA) ≥ II, EF ≤35%, elevated natriuretic peptides and either current hospitalization for HF or history of hospitalization/ emergency department visit for HF within a year were randomized to either placebo or omecamtiv mecarbil (pharmacokinetic‐guided dosing: 25, 37.5 or 50 mg bid). 8256 patients [male (79%), non‐white (22%), mean age 65 years] were enrolled with a mean EF 27%, ischemic etiology in 54%, NYHA II 53% and III/IV 47%, and median NT‐proBNP 1971 pg/mL. HF therapies at baseline were among the most effectively employed in contemporary HF trials. GALACTIC‐HF randomized patients representative of recent HF registries and trials with substantial numbers of patients also having characteristics understudied in previous trials including more from North America (n = 1386), enrolled as inpatients (n = 2084), systolic blood pressure < 100 mmHg (n = 1127), estimated glomerular filtration rate < 30 mL/min/1.73 m2 (n = 528), and treated with sacubitril‐valsartan at baseline (n = 1594).
Conclusions:
GALACTIC‐HF enrolled a well‐treated, high‐risk population from both inpatient and outpatient settings, which will provide a definitive evaluation of the efficacy and safety of this novel therapy, as well as informing its potential future implementation
Ultralight vector dark matter search using data from the KAGRA O3GK run
Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM
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