2,710 research outputs found
Application of Data Compression Methods to the Redshift-space distortions of the PSCz galaxy catalogue
We apply a spherical harmonic analysis to the Point Source Redshift Survey (PSCz), to compute the real-space galaxy power spectrum and the degree of redshift distortion caused by peculiar velocities. We employ new parameter eigenvector and hierarchical data compression techniques, allowing a much larger number of harmonic modes to be included, and correspondingly smaller error bars. Using 4644 harmonic modes, compressed to 2278, we find that the IRAS redshift-space distortion parameter is and the amplitude of galaxy clustering on a scale of is . Combining these we find the amplitude of mass perturbations is . A preliminary model fitting analysis combining the PSCz amplitudes with the CMB and abundance of clusters yields the cosmological matter density parameter , the amplitude of primordial perturbations , and the IRAS bias parameter
Redshift Distortions and Clustering in the PSCz Survey
We have constrained the redshift-distortion parameter and the real-space power spectrum of the IRAS PSCz survey using a spherical-harmonic redshift-distortion analysis combined with a data compression method which is designed to deal with correlated parameters. Our latest result, , strongly rules out
Passive tobacco exposure may impair symptomatic improvement in patients with chronic angina undergoing enhanced external counterpulsation
<p>Abstract</p> <p>Background</p> <p>The adverse effects of tobacco abuse on cardiovascular outcomes are well-known. However, the impact of passive smoke exposure on angina status and therapeutic response is less well-established. We examined the impact of second-hand smoke (SHS) exposure on symptomatic improvement in patients with chronic ischemic coronary disease undergoing enhanced external counterpulsation (EECP).</p> <p>Methods</p> <p>This observational study included 1,026 non-smokers (108 exposed and 918 not-exposed to SHS) from the Second International EECP Patient Registry. We also assessed angina response in 363 current smokers. Patient demographics, symptomatic improvement and quality of life assessment were determined by self-report prior and after EECP treatment.</p> <p>Results</p> <p>Non-smoking SHS subjects had a lower prevalence of prior revascularization (85% vs 90%), and had an increased prevalence of stroke (13% vs 7%) and prior smoking (72% vs 61%; all p < 0.05) compared to non-smokers without SHS exposure. Despite comparable degrees of coronary disease, baseline angina class, medical regimens and side effects during EECP, fewer SHS non-smokers completed a full 35-hour treatment course (77% vs 85%, p = 0.020) compared to non-smokers without SHS. Compared to non-smokers without SHS, non-smoking SHS subjects had less angina relief after EECP (angina class decreased ≥ 1 class: 68% vs 79%; p = 0.0082), both higher than that achieved in current smokers (66%). By multivariable logistic regression, SHS exposure was an independent predictor of failure to symptomatic improvement after EECP among non-smokers (OR 1.81, 95% confidence intervals 1.16–2.83).</p> <p>Conclusion</p> <p>Non-smokers with SHS exposure had an attenuated improvement in anginal symptoms compared to those without SHS following EECP.</p
Effect of Pulsed or Continuous Delivery of Salt on Sensory Perception Over Short Time Intervals
Salt in the human diet is a major risk factor for hypertension and many countries have set targets to reduce
salt consumption. Technological solutions are being sought
to lower the salt content of processed foods without altering their taste. In this study, the approach was to deliver salt solutions in pulses of different concentrations to determine whether a pulsed delivery profile affected sensory perception of salt. Nine different salt profiles were delivered by a Dynataste device and a trained panel assessed their saltiness using time–intensity and single-score sensory techniques. The profile duration (15 s) was designed to match eating conditions and the effects of intensity and duration of the pulses on sensory perception were investigated. Sensory results from the profiles delivered in either water or in a bouillon base were not statistically different. Maximum perceived salt intensities and the area under the time–
intensity curves correlated well with the overall perceived
saltiness intensity despite the stimulus being delivered as
several pulses. The overall saltiness scores for profiles
delivering the same overall amount of sodium were statistically not different from one another suggesting that, in this system, pulsed delivery did not enhance salt
perception but the overall amount of salt delivered in each
profile did affect sensory perception
Extracellular Hsp72 concentration relates to a minimum endogenous criteria during acute exercise-heat exposure
Extracellular heat-shock protein 72 (eHsp72) concentration increases during exercise-heat stress when conditions elicit physiological strain. Differences in severity of environmental and exercise stimuli have elicited varied response to stress. The present study aimed to quantify the extent of increased eHsp72 with increased exogenous heat stress, and determine related endogenous markers of strain in an exercise-heat model. Ten males cycled for 90 min at 50% O2peak in three conditions (TEMP, 20°C/63% RH; HOT, 30.2°C/51%RH; VHOT, 40.0°C/37%RH). Plasma was analysed for eHsp72 pre, immediately post and 24-h post each trial utilising a commercially available ELISA. Increased eHsp72 concentration was observed post VHOT trial (+172.4%) (P<0.05), but not TEMP (-1.9%) or HOT (+25.7%) conditions. eHsp72 returned to baseline values within 24hrs in all conditions. Changes were observed in rectal temperature (Trec), rate of Trec increase, area under the curve for Trec of 38.5°C and 39.0°C, duration Trec ≥ 38.5°C and ≥ 39.0°C, and change in muscle temperature, between VHOT, and TEMP and HOT, but not between TEMP and HOT. Each condition also elicited significantly increasing physiological strain, described by sweat rate, heart rate, physiological strain index, rating of perceived exertion and thermal sensation. Stepwise multiple regression reported rate of Trec increase and change in Trec to be predictors of increased eHsp72 concentration. Data suggests eHsp72 concentration increases once systemic temperature and sympathetic activity exceeds a minimum endogenous criteria elicited during VHOT conditions and is likely to be modulated by large, rapid changes in core temperature
Survival and Growth of Hatchling Crocodylus porosus in Saltwater Without Access to Fresh Drinking Water
It has been suggested that C. porosus select nest sites which provide a source of freshwater for hatchlings during the dry season. From a mark-recapture study, we conclude that hatchling C. porosus can survive and grow in hyperosmotic saltwater without drinking fresh water. Hence, the siting of nests is unlikely to be the consequence of a requirement by hatchlings for fresh water. Considered along with other information, our observations imply that hatchling C. porosus have functional salt glands
Dynamic Carboniferous tropical forests: new views of plant function and potential for physiological forcing of climate
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138385/1/nph14700_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138385/2/nph14700.pd
Comparative population structure of <i>Plasmodium malariae</i> and <i>Plasmodium falciparum</i> under different transmission settings in Malawi
<b>Background:</b> Described here is the first population genetic study of Plasmodium malariae, the causative agent of quartan malaria. Although not as deadly as Plasmodium falciparum, P. malariae is more common than previously thought, and is frequently in sympatry and co-infection with P. falciparum, making its study increasingly important. This study compares the population parameters of the two species in two districts of Malawi with different malaria transmission patterns - one seasonal, one perennial - to explore the effects of transmission on population structures.
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<b>Methods:</b> Six species-specific microsatellite markers were used to analyse 257 P. malariae samples and 257 P. falciparum samples matched for age, gender and village of residence. Allele sizes were scored to within 2 bp for each locus and haplotypes were constructed from dominant alleles in multiple infections. Analysis of multiplicity of infection (MOI), population differentiation, clustering of haplotypes and linkage disequilibrium was performed for both species. Regression analyses were used to determine association of MOI measurements with clinical malaria parameters.
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<b>Results:</b> Multiple-genotype infections within each species were common in both districts, accounting for 86.0% of P. falciparum and 73.2% of P. malariae infections and did not differ significantly with transmission setting. Mean MOI of P. falciparum was increased under perennial transmission compared with seasonal (3.14 vs 2.59, p = 0.008) and was greater in children compared with adults. In contrast, P. malariae mean MOI was similar between transmission settings (2.12 vs 2.11) and there was no difference between children and adults. Population differentiation showed no significant differences between villages or districts for either species. There was no evidence of geographical clustering of haplotypes. Linkage disequilibrium amongst loci was found only for P. falciparum samples from the seasonal transmission setting.
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<b>Conclusions:</b> The extent of similarity between P. falciparum and P. malariae population structure described by the high level of multiple infection, the lack of significant population differentiation or haplotype clustering and lack of linkage disequilibrium is surprising given the differences in the biological features of these species that suggest a reduced potential for out-crossing and transmission in P. malariae. The absence of a rise in P. malariae MOI with increased transmission or a reduction in MOI with age could be explained by differences in the duration of infection or degree of immunity compared to P. falciparum
Numerical study of circulation on the inner Amazon Shelf
Author Posting. © Springer, 2008. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Ocean Dynamics 58 (2008): 187-198, doi:10.1007/s10236-008-0139-4.We studied the circulation on the coastal
domain of the Amazon Shelf by applying the hydrodynamic
module of the Estuarine and Coastal Ocean
Model and Sediment Transport - ECOMSED. The first
barotropic experiment aimed to explain the major bathymetric
effects on tides and those generated by anisotropy
in sediment distribution. We analyzed the continental
shelf response of barotropic tides under realistic bottom
stress parametrization (Cd), considering sediment granulometry
obtained from a faciologic map, where river
mud deposits and reworked sediments areas are well distinguished,
among others classes of sediments. Very low
Cd values were set in the fluid mud regions off the Amapa
coast (1.0 10-4 ), in contrast to values around 3:5 10-3
for coarser sediment regions off the Para coast. Three-dimensional
experiments represented the Amazon River
discharge and trade winds, combined to barotropic tide
influences and induced vertical mixing. The quasi-resonant
response of the Amazon Shelf to the M2 tide act on
the local hydrodynamics by increasing tidal admittance,
along with tidal forcing at the shelf break and extensive
fluid mud regions. Harmonic analysis of modeled
currents agreed well with analysis of the AMASSEDS
observational data set. Tidal-induced vertical shear provided
strong homogenization of threshold waters, which
are subject to a kind of hydraulic control due to the topographic
steepness. Ahead of the hydraulic jump, the
low-salinity plume is disconnected from the bottom and
acquires negative vorticity, turning southeastward. Tides
act as a generator mechanism and topography, via hydraulic
control, as a maintainer mechanism for the low-salinity
frontal zone positioning. Tidally induced southeastward
plume fate is overwhelmed by northwestward
trade winds so that, along with background circulation,
probably play the most important role on the plume fate
and variability over the Amazon Shelf
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