277 research outputs found
Binaries with total eclipses in the LMC: potential targets for spectroscopy
35 Eclipsing binaries presenting unambiguous total eclipses were selected
from a subsample of the list of Wyrzykowski et al. (2003). The photometric
elements are given for the I curve in DiA photometry, as well as approximate
Teff and masses of the components. The interest of these systems is stressed in
view of future spectroscopic observations.Comment: 4 pages, 1 figure; poster presented at the conference "Close binaries
in the 21st Century: new opportunities and challenges", Syros, 27-30 June
200
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Stand conditions associated with tree regeneration in Sierran mixed-conifer forests
Fire suppression has significantly increased canopy cover, litter depth, and stem density in many
western forests, altering microsite conditions that affect tree seedling establishment. We conducted studies in a
mixed-conifer forest in the Sierra Nevada, California, to determine relationships between established understory
trees and microsite quality, and to examine the effect of fire intensity and shrub cover on seedling establishment.
Most of the conifer species were found on microsites with relatively high soil moisture and relatively low direct
solar radiation. All species had greater frequency under shadier conditions except for Jeffrey pine, which was
found on drier, more open microsites. Although seedlings were more abundant on mineral soil than expected,
intact litter and forest floor was not a barrier to establishment. Mortality of planted seedlings was high,
particularly in exposed areas. Although shrub cover may initially aid survival, few conifer saplings were present
in shrub-dominated patches, possibly because shrubs can be aggressive competitors for soil moisture. The
lack of regeneration, logs, or snags in many openings suggest that large gaps are hostile environments for
tree seedlings. Results suggest that reductions in shrub cover may benefit tree establishment, but increasing
understory light and decreasing surface soil moisture through canopy cover reductions may not. FOR. SCI.
51(3):198 â210.Keywords: Prunus emarginata, Old-growth, Abies magnifica, Natural regeneration, Pinus jeffreyi, Quercus kelloggii, Arctostaphylos patula, Pinus labertiana, Abies concolor, Calocedrus decurrens, Fire, Shrub competition, Ceanothus cordulatus, Microclimat
The novel ASIC2 locus is associated with severe gingival inflammation
An increasing body of evidence suggests a significant genetic regulation of inflammatory response mechanisms; however, little is known regarding the genetic determinants of severe gingival inflammation (GI). We conducted a genomewide association study of severe GI among 4,077 European American adults, participants in the Dental Atherosclerosis Risk in Communities cohort. The severe GI trait was defined dichotomously with the 90th percentile of gingival index â„2 extent score. Genotyping was performed with the Affymetrix 6.0 array platform, and an imputed set of 2.5 million markers, based on HapMap Phase II CEU build 36, was interrogated. Genetic models were based on logistic regression and controlled for ancestry (10 principal components), sex, age, and examination center. One locus on chromosome 17 met genomewide statistical significance criteriaâlead single-nucleotide polymorphism: rs11652874 (minor allele frequency = 0.06, intronic to ASIC2 [acidsensing ionic channel 2, formerly named ACCN1]; odds ratio = 2.1, 95% confidence interval = 1.6 to 2.7, P = 3.9 Ă 10-8). This association persisted among subjects with severe periodontitis and was robust to adjustment for microbial plaque index. Moreover, the minor (G) allele was associated with higher levels of severe GI in stratified analyses among subsets of participants with high load of either âredâ or âorangeâ complex pathogens, although this association was not statistically significant. While these results will require replication in independent samples and confirmation by mechanistic studies, this locus appears as a promising candidate for severe GI. Our findings suggest that genetic variation in ASIC2 is significantly associated with severe GI and that the association is plaque independent. Knowledge Transfer Statement: Persistent gingival inflammation reflected by bleeding usually precedes ongoing attachment loss or periodontal disease progression. Our findings suggest that genetic variation in ASIC2 that is associated with severe gingival inflammation might be used as a genetic marker to identify people at higher risk for periodontal disease. Ongoing studies to uncover the mechanistic link between ASIC2 and gingival inflammation could lead to novel therapeutic interventions
Genome-wide association study of 1,5-anhydroglucitol identifies novel genetic loci linked to glucose metabolism
1,5-anhydroglucitol (1,5-AG) is a biomarker of hyperglycemic excursions associated with diabetic complications. Because of its structural similarity to glucose, genetic studies of 1,5-AG can deliver complementary insights into glucose metabolism. We conducted genome-wide association studies of serum 1,5-AG concentrations in 7,550 European ancestry (EA) and 2,030 African American participants (AA) free of diagnosed diabetes from the ARIC Study. Seven loci in/near EFNA1/SLC50A1, MCM6/LCT, SI, MGAM, MGAM2, SLC5A10, and SLC5A1 showed genome-wide significant associations (P < 5 Ă 10-8) among EA participants, five of which were novel. Six of the seven loci were successfully replicated in 8,790 independent EA individuals, and MCM6/LCT and SLC5A10 were also associated among AA. Most of 1,5-AG-associated index SNPs were not associated with the clinical glycemic markers fasting glucose or theHbA1c, and vice versa. Only the index variant in SLC5A1 showed a significant association with fasting glucose in the expected opposing direction. Products of genes in all 1,5-AG-associated loci have known roles in carbohydrate digestion and enteral or renal glucose transport, suggesting that genetic variants associated with 1,5-AG influence its concentration via effects on glucose metabolism and handling
Phenomenology of the Lense-Thirring effect in the Solar System
Recent years have seen increasing efforts to directly measure some aspects of
the general relativistic gravitomagnetic interaction in several astronomical
scenarios in the solar system. After briefly overviewing the concept of
gravitomagnetism from a theoretical point of view, we review the performed or
proposed attempts to detect the Lense-Thirring effect affecting the orbital
motions of natural and artificial bodies in the gravitational fields of the
Sun, Earth, Mars and Jupiter. In particular, we will focus on the evaluation of
the impact of several sources of systematic uncertainties of dynamical origin
to realistically elucidate the present and future perspectives in directly
measuring such an elusive relativistic effect.Comment: LaTex, 51 pages, 14 figures, 22 tables. Invited review, to appear in
Astrophysics and Space Science (ApSS). Some uncited references in the text
now correctly quoted. One reference added. A footnote adde
Genome-wide association study of serum fructosamine and glycated albumin in adults without diagnosed diabetes: Results from the atherosclerosis risk in communities study
Fructosamine and glycated albumin are potentially useful alternatives to hemoglobin A1c (HbA1c) as diabetes biomarkers. The genetic determinants of fructosamine and glycated albumin, however, are unknown. We performed genome-wide association studies of fructosamine and glycated albumin among 2,104 black and 7,647 white participants without diabetes in the Atherosclerosis Risk in Communities (ARIC) Study and replicated findings in the Coronary Artery Risk Development in Young Adults (CARDIA) study. Among whites, rs34459162, a novel missense single nucleotide polymorphism (SNP) in RCN3, was associated with fructosamine (P = 5.3 3 1029) and rs1260236, a known diabetes-related missense mutation in GCKR, was associated with percent glycated albumin (P = 5.9 3 1029) and replicated in CARDIA. We also found two novel associations among blacks: an intergenic SNP, rs2438321, associated with fructosamine (P = 6.2 3 1029), and an intronic variant in PRKCA, rs59443763, associated with percent glycated albumin (P = 4.1 3 1029), but these results did not replicate. Few established fasting glucose or HbA1c SNPs were also associated with fructosamine or glycated albumin. Overall, we found genetic variants associated with the glycemic information captured by fructosamine and glycated albumin as well as with their nonglycemic component. This highlights the importance of examining the genetics of hyperglycemia biomarkers to understand the information they capture, including potential glucose-independent factors
GWAS for Interleukin-1ÎČ levels in gingival crevicular fluid identifies IL37 variants in periodontal inflammation
There is no agnostic GWAS evidence for the genetic control of IL-1ÎČ expression in periodontal disease. Here we report a GWAS for âhighâ gingival crevicular fluid IL-1ÎČ expression among 4910 European-American adults and identify association signals in the IL37 locus. rs3811046 at this locus (p = 3.3 Ă 10â22) is associated with severe chronic periodontitis (OR = 1.50; 95% CI = 1.12â2.00), 10-year incident tooth loss (â„3 teeth: RR = 1.33; 95% CI = 1.09â1.62) and aggressive periodontitis (OR = 1.12; 95% CI = 1.01â1.26) in an independent sample of 4927 German/Dutch adults. The minor allele at rs3811046 is associated with increased expression of IL-1ÎČ in periodontal tissue. In RAW macrophages, PBMCs and transgenic mice, the IL37 variant increases expression of IL-1ÎČ and IL-6, inducing more severe periodontal disease, while IL-37 protein production is impaired and shows reduced cleavage by caspase-1. A second variant in the IL37 locus (rs2708943, p = 4.2 Ă 10â7) associates with attenuated IL37 mRNA expression. Overall, we demonstrate that IL37 variants modulate the inflammatory cascade in periodontal disease
Determinants of Enterprise Restructuring in Transition: Description of a Survey in Russian Industry
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