467 research outputs found
Molecular astronomy of cool stars and sub-stellar objects
The optical and infrared spectra of a wide variety of `cool' astronomical
objects including the Sun, sunspots, K-, M- and S-type stars, carbon stars,
brown dwarfs and extrasolar planets are reviewed. The review provides the
necessary astronomical background for chemical physicists to understand and
appreciate the unique molecular environments found in astronomy. The
calculation of molecular opacities needed to simulate the observed spectral
energy distributions is discussed
Metal-macrofauna interactions determine microbial community structure and function in copper contaminated sediments
Peer reviewedPublisher PD
A Triple Protostar System Formed via Fragmentation of a Gravitationally Unstable Disk
Binary and multiple star systems are a frequent outcome of the star formation
process, and as a result, almost half of all sun-like stars have at least one
companion star. Theoretical studies indicate that there are two main pathways
that can operate concurrently to form binary/multiple star systems: large scale
fragmentation of turbulent gas cores and filaments or smaller scale
fragmentation of a massive protostellar disk due to gravitational instability.
Observational evidence for turbulent fragmentation on scales of 1000~AU has
recently emerged. Previous evidence for disk fragmentation was limited to
inferences based on the separations of more-evolved pre-main sequence and
protostellar multiple systems. The triple protostar system L1448 IRS3B is an
ideal candidate to search for evidence of disk fragmentation. L1448 IRS3B is in
an early phase of the star formation process, likely less than 150,000 years in
age, and all protostars in the system are separated by 200~AU. Here we
report observations of dust and molecular gas emission that reveal a disk with
spiral structure surrounding the three protostars. Two protostars near the
center of the disk are separated by 61 AU, and a tertiary protostar is
coincident with a spiral arm in the outer disk at a 183 AU separation. The
inferred mass of the central pair of protostellar objects is 1 M,
while the disk surrounding the three protostars has a total mass of 0.30
M_{\sun}. The tertiary protostar itself has a minimum mass of 0.085
M. We demonstrate that the disk around L1448 IRS3B appears susceptible
to disk fragmentation at radii between 150~AU and 320~AU, overlapping with the
location of the tertiary protostar. This is consistent with models for a
protostellar disk that has recently undergone gravitational instability,
spawning one or two companion stars.Comment: Published in Nature on Oct. 27th. 24 pages, 8 figure
Studies of the Association of Arg72Pro of Tumor Suppressor Protein p53 with Type 2 Diabetes in a Combined Analysis of 55,521 Europeans
A study of 222 candidate genes in type 2 diabetes reported association of variants in RAPGEF1, ENPP1, TP53, NRF1, SLC2A2, SLC2A4 and FOXC2 with type 2 diabetes in 4,805 Finnish individuals. We aimed to replicate these associations in a Danish case-control study and to substantiate any replicated associations in meta-analyses. Furthermore, we evaluated the impact on diabetes-related intermediate traits in a population-based sample of middle-aged Danes.We genotyped nine lead variants in the seven genes in 4,973 glucose-tolerant and 3,612 type 2 diabetes Danish individuals. In meta-analyses we combined case-control data from the DIAGRAM+ Consortium (n = 47,117) and the present genotyping results. The quantitative trait studies involved 5,882 treatment-naive individuals from the Danish Inter99 study.None of the nine investigated variants were significantly associated with type 2 diabetes in the Danish samples. However, for all nine variants the estimate of increase in type 2 diabetes risk was observed for the same allele as previously reported. In a meta-analysis of published and online data including 55,521 Europeans the G-allele of rs1042522 in TP53 showed significant association with type 2 diabetes (OR = 1.06 95% CI 1.02-1.11, p = 0.0032). No substantial associations with diabetes-related intermediary phenotypes were found.The G-allele of TP53 rs1042522 is associated with an increased prevalence of type 2 diabetes in a combined analysis of 55,521 Europeans
Non-Replication of Genome-Wide Based Associations between Common Variants in INSIG2 and PFKP and Obesity in Studies of 18,014 Danes
(rs17782313) as genetic risk factors.â=â2,158) from Steno Diabetes Center. rs17782313 were observed. rs7566605 may influence the level of BMI in combination with the level of physical activity
Mechanisms for reducing low back pain: a mediation analysis of a multifaceted intervention in workers in elderly care
Purpose A multifaceted workplace intervention consisting of participatory ergonomics, physical training, and cognitiveâbehavioural training (CBT) has shown effectiveness for reducing low back pain (LBP). However, the mechanisms of action underlying these intervention components are not well understood. Methods This was a mediation analysis of a cluster-randomised controlled trial of a multifaceted intervention in 420 workers in elderly care. Mediation analysis was carried out via structural equation modelling. Potential mediators investigated were: fear-avoidance beliefs, perceived muscle strength, use of assistive devices at work and perceived physical exertion at work. LBP outcomes assessed were: days with LBP, LBP intensity and days with bothersome LBP. Results There were no significant indirect effects of the intervention on LBP outcomes. There were significant effects of the intervention on both fear-avoidance measures [β = ââ0.63, 95% CI (1.23, 0.03); β = ââ1.03, 95% CI (ââ1.70, ââ0.34)] and the use of assistive devices [β = ââ0.55, 95% CI (ââ1.04, ââ0.05)], but not on perceived muscle strength [β = ââ0.18, 95% CI (ââ0.50, 0.13)] or physical exertion [β = ââ0.05, 95% CI (ââ0.40, 0.31)]. The only potential mediator with a significant effect on LBP outcomes was physical exertion, which had a significant effect on LBP intensity [βâ=â0.14, 95% CI (0.04, 0.23)]. Conclusions A multifaceted intervention consisting of participatory ergonomics, physical training, and CBT was able to decrease fear-avoidance beliefs and increase use of assistive devices in the workplace. However, these changes did not explain the effect of any of the intervention components on days with LBP, LBP intensity and days with bothersome LBP
Effect of hemicellulose liquid phase on the enzymatic hydrolysis of autohydrolyzed Eucalyptus globulus wood
In this work, Eucalyptus globulus wood was pretreated under non-isothermal autohydrolysis process at 210, 220, and 230 °C, obtaining a pretreated solid with high cellulose content and a hemicellulosic liquid phase (HLP) containing mainly xylose, acetic acid, furfural, xylooligosaccharides, and phenolic compounds. The maximum concentration of xylooligosaccharides (8.97 g/L) and phenolic compounds (2.66 g/L) was obtained at 210 and 230 °C, respectively. To evaluate the effect of HLP addition on the enzymatic hydrolysis using unwashed pretreated solid as substrate, different proportions of HLP were studied. Also, in order to use the whole slurry on enzymatic hydrolysis, the supplementation of xylanases was evaluated. Glucose concentration of 107.49 g/L (corresponding to 74.65 % of conversion) was obtained using pretreated solid at 220 °C liquid/solid ratio (LSR) of 4 g/g and enzyme solid ratio (ESR) of 25 FPU/gwithout the addition of HLP. Thus, it was shown that the unwashed pretreated solids are susceptible to enzymatic hydrolysis contributing to reduce operational cost (water consumption). Additionally, the influence of the inhibitory compounds in the HLP was shown to affect the enzymatic hydrolysis. Results indicated that 82.52 g/L of glucose (59.37 % of conversion) was obtained, using 100 % of HLP at LSR of 4 g/g and ESR of 16 FPU/g at 210 °C of pretreated solid. However, a positive effect was shown on the enzymatic hydrolysis when the xylanases were added using 100 % of HLP, increasing to 35 and 27 % in the glucose production with respect to whole slurry without addition of xylanases.The authors A. Romani and F. B. Pereira thank to the Portuguese Foundation for Science and Technology (FCT, Portugal) for their fellowships (grant number, SFRH/BPD/77995/2011 and SFRH/BD/64776/2009, respectively)
New genetic loci implicated in fasting glucose homeostasis and their impact on type 2 diabetes risk.
Levels of circulating glucose are tightly regulated. To identify new loci influencing glycemic traits, we performed meta-analyses of 21 genome-wide association studies informative for fasting glucose, fasting insulin and indices of beta-cell function (HOMA-B) and insulin resistance (HOMA-IR) in up to 46,186 nondiabetic participants. Follow-up of 25 loci in up to 76,558 additional subjects identified 16 loci associated with fasting glucose and HOMA-B and two loci associated with fasting insulin and HOMA-IR. These include nine loci newly associated with fasting glucose (in or near ADCY5, MADD, ADRA2A, CRY2, FADS1, GLIS3, SLC2A2, PROX1 and C2CD4B) and one influencing fasting insulin and HOMA-IR (near IGF1). We also demonstrated association of ADCY5, PROX1, GCK, GCKR and DGKB-TMEM195 with type 2 diabetes. Within these loci, likely biological candidate genes influence signal transduction, cell proliferation, development, glucose-sensing and circadian regulation. Our results demonstrate that genetic studies of glycemic traits can identify type 2 diabetes risk loci, as well as loci containing gene variants that are associated with a modest elevation in glucose levels but are not associated with overt diabetes
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