115 research outputs found
WMAP5 and the Cluster Mass Function
The recently revised cosmological constraints from the Five-Year WMAP data
ameliorate previous tension between cosmological constraints from the microwave
background and from cluster abundances. We demonstrate that the revised
estimates of cosmological parameters are in excellent agreement with the mass
function of X-ray clusters in the Sloan Digital Sky Survey. Velocity
segregation between galaxies and the underlying dark matter could cause virial
mass estimates to be biased, causing the mass scale of the mass function to be
offset from the true value. Modest velocity segregation
(=1.13) is sufficient to match the
mass function to the Five-Year WMAP results. When the new WMAP results are
combined with constraints from supernovae and baryon acoustic oscillations,
there is no need for velocity segregation
(=1.050.05). This result agrees with
expectations for velocity segregation from state-of-the-art numerical
simulations of clusters. Together with the improved agreement between the new
WMAP results and recent cosmic shear measurements, this result demonstrates
that the amplitude of large-scale structure in the nearby universe matches that
predicted from the structure seen in the microwave background. The new
constraint we place on velocity segregation in clusters indicates that virial
mass estimates for clusters are reasonably accurate. This result suggests that
future cluster surveys will be able to probe both cosmological parameters and
fundamental cluster physics.Comment: 4 pages, 2 color figures, submitted to ApJ Letter
Local Population Structure and Patterns of Western Hemisphere Dispersal for Coccidioides spp., the Fungal Cause of Valley Fever.
UnlabelledCoccidioidomycosis (or valley fever) is a fungal disease with high morbidity and mortality that affects tens of thousands of people each year. This infection is caused by two sibling species, Coccidioides immitis and C.Ā posadasii, which are endemic to specific arid locales throughout the Western Hemisphere, particularly the desert southwest of the United States. Recent epidemiological and population genetic data suggest that the geographic range of coccidioidomycosis is expanding, as new endemic clusters have been identified in the state of Washington, well outside the established endemic range. The genetic mechanisms and epidemiological consequences of this expansion are unknown and require better understanding of the population structure and evolutionary history of these pathogens. Here we performed multiple phylogenetic inference and population genomics analyses of 68 new and 18 previously published genomes. The results provide evidence of substantial population structure in C.Ā posadasii and demonstrate the presence of distinct geographic clades in central and southern Arizona as well as dispersed populations in Texas, Mexico, South America, and Central America. Although a smaller number of C.Ā immitis strains were included in the analyses, some evidence of phylogeographic structure was also detected in this species, which has been historically limited to California and Baja, Mexico. Bayesian analyses indicated that C.Ā posadasii is the more ancient of the two species and that Arizona contains the most diverse subpopulations. We propose a southern Arizona-northern Mexico origin for C.Ā posadasii and describe a pathway for dispersal and distribution out of this region.ImportanceCoccidioidomycosis, or valley fever, is caused by the pathogenic fungi Coccidioides posadasii and C.Ā immitis The fungal species and disease are primarily found in the American desert southwest, with spotted distribution throughout the Western Hemisphere. Initial molecular studies suggested a likely anthropogenic movement of C.Ā posadasii from North America to South America. Here we comparatively analyze eighty-six genomes of the two Coccidioides species and establish local and species-wide population structures to not only clarify the earlier dispersal hypothesis but also provide evidence of likely ancestral populations and patterns of dispersal for the known subpopulations of C.Ā posadasii
Epidemiology and Investigation of Melioidosis, Southern Arizona
Burkholderia pseudomallei is a bacterium endemic to Southeast Asia and northern Australia, but it has not been found to occur endemically in the United States. We report an ostensibly autochthonous case of melioidosis in the United States. Despite an extensive investigation, the source of exposure was not identified
Tsunami waves extensively resurfaced the shorelines of an early Martian ocean
It has been proposed that ~3.4 billion years ago an ocean fed by enormous
catastrophic floods covered most of the Martian northern lowlands. However, a
persistent problem with this hypothesis is the lack of definitive
paleoshoreline features. Here, based on geomorphic and thermal image mapping
in the circum-Chryse and northwestern Arabia Terra regions of the northern
plains, in combination with numerical analyses, we show evidence for two
enormous tsunami events possibly triggered by bolide impacts, resulting in
craters ~30ākm in diameter and occurring perhaps a few million years apart.
The tsunamis produced widespread littoral landforms, including run-up water-
ice-rich and bouldery lobes, which extended tens to hundreds of kilometers
over gently sloping plains and boundary cratered highlands, as well as
backwash channels where wave retreat occurred on highland-boundary surfaces.
The ice-rich lobes formed in association with the younger tsunami, showing
that their emplacement took place following a transition into a colder global
climatic regime that occurred after the older tsunami event. We conclude that,
on early Mars, tsunamis played a major role in generating and resurfacing
coastal terrains
A Case-Control Study of Hantavirus Pulmonary Syndrome during an Outbreak in the Southwestern United States
In May 1993, an outbreak of hantavirus pulmonary syndrome( HPS) occurred in the south-western United States. A case-control study determined risk factors for HPS. Seventeen case-patients were compared with 3 groups of controls: members of case-patient households( household controls), members of neighboring households( near controls), and members of randomly selected households ā„ 24 km away ( far controls). Investigators trapped more small rodents at case households than at near ( P = .03) or far control households( P = .02). After the number of small rodents was controlled for,case-patients were more likely than household controls to hand plow (odds ratio [OR], 12.3; 95% confidence interval [ CI], 1.1-143.0) or to clean feed storage areas (OR, 33.4; 95% CI, 1.7-666.0). Case-patients were more likely than near controls to plant( OR, 6.2; 95% CI, 1.1-34.0) and more likely than far controls to clean animal sheds( OR, 11.9;95% CI, 1.4-103.0). Peridomestic cleaning, agricultural activities, and an increased number of small rodents at the household were associated with HPS
A Case-Control Study of Hantavirus Pulmonary Syndrome during an Outbreak in the Southwestern United States
In May 1993, an outbreak of hantavirus pulmonary syndrome( HPS) occurred in the south-western United States. A case-control study determined risk factors for HPS. Seventeen case-patients were compared with 3 groups of controls: members of case-patient households( household controls), members of neighboring households( near controls), and members of randomly selected households ā„ 24 km away ( far controls). Investigators trapped more small rodents at case households than at near ( P = .03) or far control households( P = .02). After the number of small rodents was controlled for,case-patients were more likely than household controls to hand plow (odds ratio [OR], 12.3; 95% confidence interval [ CI], 1.1-143.0) or to clean feed storage areas (OR, 33.4; 95% CI, 1.7-666.0). Case-patients were more likely than near controls to plant( OR, 6.2; 95% CI, 1.1-34.0) and more likely than far controls to clean animal sheds( OR, 11.9;95% CI, 1.4-103.0). Peridomestic cleaning, agricultural activities, and an increased number of small rodents at the household were associated with HPS
Climatic and environmental patterns associated with hantavirus pulmonary syndrome, Four Corners region, United States.
To investigate climatic, spatial, temporal, and environmental patterns associated with hantavirus pulmonary syndrome (HPS) cases in the Four Corners region, we collected exposure site data for HPS cases that occurred in 1993 to 1995. Cases clustered seasonally and temporally by biome type and geographic location, and exposure sites were most often found in pinyon-juniper woodlands, grasslands, and Great Basin desert scrub lands, at elevations of 1,800 m to 2,500 m. Environmental factors (e.g., the dramatic increase in precipitation associated with the 1992 to 1993 El NiƱo) may indirectly increase the risk for Sin Nombre virus exposure and therefore may be of value in designing disease prevention campaigns
Puromycin-sensitive aminopeptidase protects against aggregation-prone proteins via autophagy
A major function of proteasomes and macroautophagy is to eliminate misfolded potentially toxic proteins. Mammalian proteasomes, however, cannot cleave polyglutamine (polyQ) sequences and seem to release polyQ-rich peptides. Puromycin-sensitive aminopeptidase (PSA) is the only cytosolic enzyme able to digest polyQ sequences. We tested whether PSA can protect against accumulation of polyQ fragments. In cultured cells, Drosophila and mouse muscles, PSA inhibition or knockdown increased aggregate content and toxicity of polyQ-expanded huntingtin exon 1. Conversely, PSA overexpression decreased aggregate content and toxicity. PSA inhibition also increased the levels of polyQ-expanded ataxin-3 as well as mutant Ī±-synuclein and superoxide dismutase 1. These protective effects result from an unexpected ability of PSA to enhance macroautophagy. PSA overexpression increased, and PSA knockdown or inhibition reduced microtubule-associated protein 1 light chain 3-II (LC3-II) levels and the amount of protein degradation sensitive to inhibitors of lysosomal function and autophagy. Thus, by promoting autophagic protein clearance, PSA helps protect against accumulation of aggregation-prone proteins and proteotoxicity
The Public Health Impact of Coccidioidomycosis in Arizona and California
The numbers of reported cases of coccidioidomycosis in Arizona and California have risen dramatically over the past decade, with a 97.8% and 91.1% increase in incidence rates from 2001 to 2006 in the two states, respectively. Of those cases with reported race/ethnicity information, Black/African Americans in Arizona and Hispanics and African/Americans in California experienced a disproportionately higher frequency of disease compared to other racial/ethnic groups. Lack of early diagnosis continues to be a problem, particularly in suspect community-acquired pneumonia, underscoring the need for more rapid and sensitive tests. Similarly, the inability of currently available therapeutics to reduce the duration and morbidity of this disease underscores the need for improved therapeutics and a preventive vaccine
H_0 from Lensed Quasars
Strong gravitational lens systems with time delays between the multiple images are a powerful probe of cosmology, particularly of the Hubble constant (H0). The H0 Lenses In COSMOGRAIL's Wellspring (H0LiCOW) project has measured H0 from lensed quasars using deep Hubble Space Telescope and AO imaging, precise time delay measurements from the COSMOGRAIL monitoring project, a measurement of the velocity dispersion of the lens galaxies, and a characterization of the mass distribution along the line of sight. Our latest results from a total of six lenses constrains H0 to be 73.3(-1.8,+1.7) km/s/Mpc for a flat Lambda CDM cosmology, which is a measurement to 2.4% precision. These results are consistent with independent determinations of H0 using type Ia supernovae calibrated by the distance ladder method, and are in 3.1-sigma tension with the results of Planck CMB measurements. Combined with the latest distance ladder results from the SH0ES project, we find a 5.3-sigma tension between Planck and late-Universe probes, hinting at possible new physics beyond the standard LCDM model and highlighting the importance of this independent probe
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