61 research outputs found
Detection of the 128 day radial velocity variations in the supergiant {\alpha} Persei. Rotational modulations, pulsations, or a planet?
Aims. In order to search for and study the nature of the low-amplitude and
long-periodic radial velocity (RV) variations of massive stars, we have been
carrying out a precise RV survey for supergiants that lie near or inside the
Cepheid instability strip.
Methods. We have obtained high-resolution spectra of {\alpha} Per (F5 Ib)
from November 2005 to September 2011 using the fiber-fed Bohyunsan Observatory
Echelle Spectrograph (BOES) at Bohyunsan Optical Astronomy Observatory (BOAO).
Results. Our measurements reveal that {\alpha} Per shows a periodic RV
variation of 128 days and a semi-amplitude of 70 m/s. We find no strong
correlation between RV variations and bisector velocity span (BVS), but the
128-d peak is indeed present in the BVS variations among several other
significant peaks in periodogram.
Conclusions. {\alpha} Per may have an exoplanet, but the combined data
spanning over 20 years seem to suggest that the 128-d RV variations have not
been stable on long-term scale, which is somewhat difficult to reconcile with
the exoplanet explanation. We do not exclude the pulsational nature of the
128-d variations in {\alpha} Per. Although we do not find clear evidence for
surface activity or rotational modulations by spots, coupled with the fact that
the expected rotation period is ~ 130 days the rotational modulation seems to
be the most likely cause of the RV variations. More observational data and
research are needed to clearly determine the origin of RV the variations in
{\alpha} Per.Comment: 7 pages, 10 figures, 4 table
The medical student
The Medical Student was published from 1888-1921 by the students of Boston University School of Medicine
Food Insufficiency Is Associated with High-Risk Sexual Behavior among Women in Botswana and Swaziland
In a cross-sectional study, Sheri Weiser and colleagues found that food insufficiency was an important risk factor for increased sexual risk-taking in women in Botswana and Swaziland
Emerging New Crop Pests: Ecological Modelling and Analysis of the South American Potato Psyllid Russelliana solanicola (Hemiptera: Psylloidea) and Its Wild Relatives
© 2017 Syfert et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Association of hypoxia inducible factor-1 alpha gene polymorphism with both type 1 and type 2 diabetes in a Caucasian (Hungarian) sample
BACKGROUND: Hypoxia inducible factor-1 alpha (HIF-1alpha) is a transcription factor that plays an important role in neo-vascularisation, embryonic pancreas beta-cell mass development, and beta cell protection. Recently a non synonymous single nucleotide polymorphism (g.C45035T SNP, rs11549465) of HIF-1alpha gene, resulting in the p.P582S amino acid change has been shown to be associated with type 2 diabetes (T2DM) in a Japanese population. Our aim was to replicate these findings on a Caucasian (Hungarian) population, as well as to study whether this genetic effect is restricted to T2DM or can be expanded to diabetes in general. METHODS: A large Caucasian sample (N = 890) was recruited including 370 T2DM, 166 T1DM and 354 healthy subjects. Genotyping was validated by two independent methods: a restriction fragment analysis (RFLP) and a real time PCR using TaqMan probes. An overestimation of heterozygotes by RFLP was observed as a consequence of a nearby SNP (rs34005929). Therefore genotyping results of the justified TaqMan system were accepted. The measured genotype distribution corresponded to Hardy-Weinberg equilibrium (P = 0.740) RESULTS: As the TT genotype was extremely rare in the population (0.6% in clinical sample and 2.5% in controls), the genotypes were grouped as T absent (CC) and T present (CT and TT). Genotype-wise analysis showed a significant increase of T present group in controls (24.0%) as compared to patients (16.8%, P = 0.008). This genetic effect was demonstrated in the separated samples of type 1 (15.1%, P = 0.020), and also in type 2 (17.6%, P = 0.032) diabetes. Allele-wise analysis gave identical results showing a higher frequency of the T allele in the control sample (13.3%) than in the clinical sample (8.7%, P = 0.002) with similar results in type 1 (7.8%, P = 0.010) and type 2 (9.1%, P = 0.011) diabetes. The odds ratio for diabetes (either type 1 or 2) was 1.56 in the presence of the C allele. CONCLUSION: We confirmed the protective effect of a rare genetic variant of HIF-1alpha gene against type 2 diabetes in a Caucasian sample. Moreover we demonstrated a genetic contribution of the same polymorphism in type 1 diabetes as well, supporting a possible overlap in pathomechanism for T2DM and a T1DM
AI is a viable alternative to high throughput screening: a 318-target study
: High throughput screening (HTS) is routinely used to identify bioactive small molecules. This requires physical compounds, which limits coverage of accessible chemical space. Computational approaches combined with vast on-demand chemical libraries can access far greater chemical space, provided that the predictive accuracy is sufficient to identify useful molecules. Through the largest and most diverse virtual HTS campaign reported to date, comprising 318 individual projects, we demonstrate that our AtomNet® convolutional neural network successfully finds novel hits across every major therapeutic area and protein class. We address historical limitations of computational screening by demonstrating success for target proteins without known binders, high-quality X-ray crystal structures, or manual cherry-picking of compounds. We show that the molecules selected by the AtomNet® model are novel drug-like scaffolds rather than minor modifications to known bioactive compounds. Our empirical results suggest that computational methods can substantially replace HTS as the first step of small-molecule drug discovery
Finishing the euchromatic sequence of the human genome
The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead
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From Famine to Feast: Developing Early-Phase Combination Immunotherapy Trials Wisely
Not until the turn of this century has immunotherapy become a fundamental component of cancer treatment. While monotherapy with immune modulators, such as immune checkpoint inhibitors, provides a subset of patients with durable clinical benefit and possible cure, combination therapy offers the potential for antitumor activity in a greater number of patients. The field of immunology has provided us with a plethora of potential molecules and pathways to target. This abundance makes it impractical to empirically test all possible combinations efficiently. We recommend that potential immunotherapy combinations be chosen based on sound rationale and available data to address the mechanisms of primary and acquired immune resistance. Novel trial designs may increase the proportion of patients receiving potentially efficacious treatments and, at the same time, better define the balance of clinical activity and safety. We believe that implementing a strategic approach in the early development of immunotherapy combinations will expedite the delivery of more effective therapies with improved safety and durable outcomes
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