2,324 research outputs found
Radio background measurements at the Pierre Auger Observatory
Mesures du bruit de fond radio sur le site de l'observatoire Pierre Auge
Cryptic diversity within the major trypanosomiasis vector Glossina fuscipes revealed by molecular markers
Background: The tsetse fly Glossina fuscipes s.l. is responsible for the transmission of approximately 90% of cases of human African trypanosomiasis (HAT) or sleeping sickness. Three G. fuscipes subspecies have been described, primarily based upon subtle differences in the morphology of their genitalia. Here we describe a study conducted across the range of this important vector to determine whether molecular evidence generated from nuclear DNA (microsatellites and gene sequence information), mitochondrial DNA and symbiont DNA support the existence of these taxa as discrete taxonomic units.
Principal Findings: The nuclear ribosomal Internal transcribed spacer 1 (ITS1) provided support for the three subspecies. However nuclear and mitochondrial sequence data did not support the monophyly of the morphological subspecies G. f.fuscipes or G. f. quanzensis. Instead, the most strongly supported monophyletic group was comprised of flies sampled fromEthiopia. Maternally inherited loci (mtDNA and symbiont) also suggested monophyly of a group from Lake Victoria basin and Tanzania, but this group was not supported by nuclear loci, suggesting different histories of these markers. Microsatellite data confirmed strong structuring across the range of G. fuscipes s.l., and was useful for deriving the interrelationship of closely related populations.
Conclusion/Significance: We propose that the morphological classification alone is not used to classify populations of G. fuscipes for control purposes. The Ethiopian population, which is scheduled to be the target of a sterile insect release (SIT) programme, was notably discrete. From a programmatic perspective this may be both positive, given that it may reflect limited migration into the area or negative if the high levels of differentiation are also reflected in reproductive isolation between this population and the flies to be used in the release programme
Nonresonant valence-to-core x-ray emission spectroscopy of niobium
The valence-to-core (V2C) portion of x-ray emission spectroscopy (XES) measures the electron states close to the Fermi level. These states are involved in bonding, thus providing a measure of the chemistry of the material. In this article, we show the V2C XES spectra for several niobium compounds. The
K
ÎČ
âČâČ
peak in the V2C XES results from the transition of a ligand
2
s
electron into the
1
s
core-hole of the niobium, a transition allowed by hybridization with the niobium
4
p
. This location in energy of this weak peak shows a strong ligand dependence, thus providing a sensitive probe of the ligand environment about the niobium
Advancing the Microbiome Research Community
The human microbiome has become a recognized factor in promoting and maintaining health. We outline opportunities in interdisciplinary research, analytical rigor, standardization, and policy development for this relatively new and rapidly developing field. Advances in these aspects of the research community may in turn advance our understanding of human microbiome biology.
It is now widely recognized that disturbances in our normal microbial populations may be linked to acute infections such as Clostridium difficile and to chronic diseases such as heart disease, cancer, obesity, and autoimmune disorders (Clemente et al., 2012). This has prompted substantial interest in the microbiome from both basic and clinical perspectives. Although our genome is relatively static throughout life, each of our microbial communities changes profoundly from infancy through adulthood, continuing to adapt through ongoing exposures to diet, drugs and environment. Understanding the microbiome and its dynamic nature may be critical for diagnostics and, eventually, interventions based on the microbiome itself. However, several important challenges limit the ability of researchers to enter the microbiome field and/or conduct research most effectively
Vaginal biogenic amines: biomarkers of bacterial vaginosis or precursors to vaginal dysbiosis?
Bacterial vaginosis (BV) is the most common vaginal disorder among reproductive age women. One clinical indicator of BV is a "fishy" odor. This odor has been associated with increases in several biogenic amines (BAs) that may serve as important biomarkers. Within the vagina, BA production has been linked to various vaginal taxa, yet their genetic capability to synthesize BAs is unknown. Using a bioinformatics approach, we show that relatively few vaginal taxa are predicted to be capable of producing BAs. Many of these taxa (Dialister, Prevotella, Parvimonas, Megasphaera, Peptostreptococcus, and Veillonella spp.) are more abundant in the vaginal microbial community state type (CST) IV, which is depleted in lactobacilli. Several of the major Lactobacillus species (L. crispatus, L. jensenii, and L. gasseri) were identified as possessing gene sequences for proteins predicted to be capable of putrescine production. Finally, we show in a small cross sectional study of 37 women that the BAs putrescine, cadaverine and tyramine are significantly higher in CST IV over CSTs I and III. These data support the hypothesis that BA production is conducted by few vaginal taxa and may be important to the outgrowth of BV-associated (vaginal dysbiosis) vaginal bacteria
The STAR Silicon Strip Detector (SSD)
The STAR Silicon Strip Detector (SSD) completes the three layers of the
Silicon Vertex Tracker (SVT) to make an inner tracking system located inside
the Time Projection Chamber (TPC). This additional fourth layer provides two
dimensional hit position and energy loss measurements for charged particles,
improving the extrapolation of TPC tracks through SVT hits. To match the high
multiplicity of central Au+Au collisions at RHIC the double sided silicon strip
technology was chosen which makes the SSD a half million channels detector.
Dedicated electronics have been designed for both readout and control. Also a
novel technique of bonding, the Tape Automated Bonding (TAB), was used to
fullfill the large number of bounds to be done. All aspects of the SSD are
shortly described here and test performances of produced detection modules as
well as simulated results on hit reconstruction are given.Comment: 11 pages, 8 figures, 1 tabl
A group-galaxy cross-correlation function analysis in zCOSMOS
We present a group-galaxy cross-correlation analysis using a group catalog
produced from the 16,500 spectra from the optical zCOSMOS galaxy survey. Our
aim is to perform a consistency test in the redshift range 0.2 < z < 0.8
between the clustering strength of the groups and mass estimates that are based
on the richness of the groups. We measure the linear bias of the groups by
means of a group-galaxy cross-correlation analysis and convert it into mass
using the bias-mass relation for a given cosmology, checking the systematic
errors using realistic group and galaxy mock catalogs. The measured bias for
the zCOSMOS groups increases with group richness as expected by the theory of
cosmic structure formation and yields masses that are reasonably consistent
with the masses estimated from the richness directly, considering the scatter
that is obtained from the 24 mock catalogs. An exception are the richest groups
at high redshift (estimated to be more massive than 10^13.5 M_sun), for which
the measured bias is significantly larger than for any of the 24 mock catalogs
(corresponding to a 3-sigma effect), which is attributed to the extremely large
structure that is present in the COSMOS field at z ~ 0.7. Our results are in
general agreement with previous studies that reported unusually strong
clustering in the COSMOS field.Comment: 13 pages, 9 figures, published in Ap
Birth after TESEâICSI in a man with hypogonadotropic hypogonadism and congenital adrenal hypoplasia linked to a DAX-1 (NR0B1) mutation
DAX1/NR0B1 mutations are responsible for X-linked congenital adrenal hypoplasia (AHC) associated with hypogonadotropic hypogonadism (HH). Few data are available concerning testicular function and fertility in men with DAX1 mutations. Azoospermia as well as failure of gonadotrophin treatment have been reported. We induced spermatogenesis in a patient who has a DAX1 mutation (c.1210C>T), leading to a stop codon in position 404 (p.Gln404X). His endocrine testing revealed a low testosterone level at 1.2 nmol/l (N: 12â40) with low FSH and LH levels at 2.1 IU/l (N: 1â5 IU/l) and 0.1 IU/l (N: 1â4 IU/l), respectively. Baseline semen analysis revealed azoospermia. Menotropin (MenopurÂź:150 IU, three times weekly) and human chorionic gonadotrophin (1500 IU, twice weekly) were used. After 20 months of treatment, as azoospermia persisted, bilateral multiple site testicular biopsies were performed. Histology revealed severe hypospermatogenesis. Rare spermatozoa were extracted from the right posterior fragment and ICSI was performed. Four embryos were obtained and, after a frozenâthawed single-embryo transfer, the patient's wife became pregnant and gave birth to a healthy boy. We report the first case of paternity after TESEâICSI in a patient with DAX1 mutation, giving potential hope to these patients to father non-affected children. Furthermore, this case illustrates the fact that patients with X-linked AHC have a primary testicular defect in addition to HH
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