Medical students’ challenges and suggestions regarding research training: a synthesis of comments from a cross-sectional survey

Background: We previously reported on a cross-sectional study of students from the Michael G. DeGroote School of Medicine at McMaster University that found most respondents wanted more opportunities to participate in research. Students provided additional comments that we synthesized to enrich the findings of our quantitative analysis.   Methods: From our previously administered 13-item, online questionnaire, run across three campuses in Ontario, Canada, 498 of 618 medical students completed our survey and 360 (72%) provided optional written comments, which we synthesized using thematic analysis in this current study.  Results: Major themes that emerged were: (1) Active student participation to identify research opportunities and interested mentors are needed; (2) Types of research involvement; (3) Uncertainty whether research training translates into useable skills; (4) Desire for a formalized research curriculum and centralization of research opportunities across campuses.  Conclusion: Programs should stress to interested students the importance of actively looking for research opportunities and consider both large and small-group educational sessions

Virial expansion for the Tan contact and Beth-Uhlenbeck formula from two-dimensional SO(2,1) anomalies

The relationship between two-dimensional SO(2,1) conformal anomalies in nonrelativistic systems and the virial expansion is explored using recently developed path-integral methods. In the process, the Beth-Uhlenbeck formula for the shift of the second virial coefficient δb2 is obtained, as well as a virial expansion for the Tan contact. A possible extension of these techniques for higher orders in the virial expansion is discussed

Private reputation retrieval in public - a privacy-aware announcement scheme for VANETs

An announcement scheme is a system that facilitates vehicles to broadcast road-related information in vehicular ad hoc networks (VANETs) in order to improve road safety and efficiency. Here, the authors propose a new cryptographic primitive for public updating of reputation score based on the Boneh–Boyen–Shacham short group signature scheme. This allows private reputation score retrieval without a secure channel. Using this, the authors devise a privacy-aware announcement scheme using reputation systems which is reliable, auditable, and robust

Breit Equation with Form Factors in the Hydrogen Atom

The Breit equation with two electromagnetic form-factors is studied to obtain a potential with finite size corrections. This potential with proton structure effects includes apart from the standard Coulomb term, the Darwin term, retarded potentials, spin-spin and spin-orbit interactions corresponding to the fine and hyperfine structures in hydrogen atom. Analytical expressions for the hyperfine potential with form factors and the subsequent energy levels including the proton structure corrections are given using the dipole form of the form factors. Numerical results are presented for the finite size corrections in the 1S and 2S hyperfine splittings in the hydrogen atom, the Sternheim observable $D_{21}$ and the 2S and 2P hyperfine splittings in muonic hydrogen. Finally, a comparison with some other existing methods in literature is presented.Comment: 24 pages, Latex, extended version, title change

A novel taxonomic marker that discriminates between morphologically complex actinomycetes

In the era where large whole genome bacterial data sets are generated routinely, rapid and accurate molecular systematics is becoming increasingly important. However, 16S ribosomal RNA sequencing does not always offer sufficient resolution to discriminate between closely related genera. The SsgA-like proteins (SALPs) are developmental regulatory proteins in sporulating actinomycete, whereby SsgB actively recruits FtsZ during sporulation-specific cell division. Here we present a novel method to classify actinomycetes, based on the extraordinary way the SsgA and SsgB proteins are conserved. The almost complete conservation of the SsgB amino acid sequence between members of the same genus, and its high divergence even between closely related genera, provides high quality data for the classification of morphologically complex actinomycetes. Our analysis validates Kitasatospora as a sister genus to Streptomyces in the family Streptomycetaceae and suggests that Micromonospora, Salinispora and Verrucosispora may represent different clades of the same genus. It is also apparent that the amino-acid sequence of SsgA is an accurate determinant for the ability of streptomycetes to produce submerged spores, dividing the phylogenetic tree of streptomycetes into LSp (liquid culture sporulation) and NLSp (no liquid culture sporulation) branches. A new phylogenetic tree of industrially relevant actinomycetes is presented and compared to that based on 16S rRNA sequences

Quantum Mechanics/Molecular Mechanics Insights into the Enantioselectivity of the O-Acetylation of (R,S)-Propranolol Catalyzed by Candida antarctica Lipase B

Classical molecular dynamics (MD) simulations and combined quantum mechanics/molecular mechanics (QM/MM) calculations were used to investigate the origin of the enantioselectivity of the Candida antarctica lipase B (CalB) catalyzed O-acetylation of (R,S)-propranolol. The reaction is a two-step process. The initial step is the formation of a reactive acyl enzyme (AcCalB) via a tetrahedral intermediate (TI-1). The stereoselectivity originates from the second step, when AcCalB reacts with the racemic substrate via a second tetrahedral intermediate (TI-2). Reaction barriers for the conversion of (R)- and (S)-propranolol to O-acetylpropranolol were computed for several distinct conformations of TI-2. In QM/MM geometry optimizations and reaction path calculations the QM region was described by density functional theory (B3LYP/TZVP) and the MM region by the CHARMM force field. The QM/MM calculations show that the formation of TI-2 is the rate-determining step. The energy barrier for transformation of (R)-propranolol to O-acetylpropranolol is 4.5 kcal/mol lower than that of the reaction of (S)-propranolol. Enzyme–substrate interactions were identified that play an important role in the enantioselectivity of the reaction. Our QM/MM calculations reproduce and rationalize the experimentally observed enantioselectivity in favor of (R)-propranolol. Furthermore, in contrast to what is commonly suggested for lipase-catalyzed reactions, our results indicate that the tetrahedral intermediate is not a good approximation of the corresponding transition states

A multi-organ transcriptome resource for the Burmese Python (Python molurus bivittatus)

<p>Abstract</p> <p>Background</p> <p>Snakes provide a unique vertebrate system for studying a diversity of extreme adaptations, including those related to development, metabolism, physiology, and venom. Despite their importance as research models, genomic resources for snakes are few. Among snakes, the Burmese python is the premier model for studying extremes of metabolic fluctuation and physiological remodelling. In this species, the consumption of large infrequent meals can induce a 40-fold increase in metabolic rate and more than a doubling in size of some organs. To provide a foundation for research utilizing the python, our aim was to assemble and annotate a transcriptome reference from the heart and liver. To accomplish this aim, we used the 454-FLX sequencing platform to collect sequence data from multiple cDNA libraries.</p> <p>Results</p> <p>We collected nearly 1 million 454 sequence reads, and assembled these into 37,245 contigs with a combined length of 13,409,006 bp. To identify known genes, these contigs were compared to chicken and lizard gene sets, and to all Genbank sequences. A total of 13,286 of these contigs were annotated based on similarity to known genes or Genbank sequences. We used gene ontology (GO) assignments to characterize the types of genes in this transcriptome resource. The raw data, transcript contig assembly, and transcript annotations are made available online for use by the broader research community.</p> <p>Conclusion</p> <p>These data should facilitate future studies using pythons and snakes in general, helping to further contribute to the utilization of snakes as a model evolutionary and physiological system. This sequence collection represents a major genomic resource for the Burmese python, and the large number of transcript sequences characterized should contribute to future research in this and other snake species.</p

Non-Response in Wave IV of the National Longitudinal Study of Adolescent Health

Non-response is a potential threat to the accuracy of estimates obtained from sample surveys and can be particularly difficult to avoid in longitudinal studies. The objective of this report is to investigate non-response and consequent bias in estimates for Wave IV of the National Longitudinal Study of Adolescent Health (Add Health). The Survey Research Unit at the University of North Carolina at Chapel Hill previously analyzed the non-response rates for the first three waves of Add Health. As shown in Chantala, Kalsbeek and Andraca, 2005, the total bias in Waves I, II, and III for 13 measures of health and risk behaviors rarely exceed 1%, which is small relative to the 20% to 80% prevalence rates for most of these measures. Results are similar for Wave IV. In this paper, first, we outline the Wave IV sampling design and results of the field work. Second, we characterize the non-response rates overall and stratified by a number of demographic variables. Next, we use data on the health risk measures reported by Wave IV responders and non-responders during their Wave I In-home interview to estimate total and relative bias due to non-response in Wave IV. We conclude with a discussion of Wave IV bias due to non-response