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This study examined the effectiveness of a formal postdoctoral education program designed to teach skills in clinical and translational science, using scholar publication rates as a measure of research productivity.
Participants included 70 clinical fellows who were admitted to a master’s or certificate training program in clinical and translational science from 1999 to 2015 and 70 matched control peers. The primary outcomes were the number of publications 5 years post-fellowship matriculation and time to publishing 15 peer-reviewed manuscripts post-matriculation.
Clinical and translational science program graduates published significantly more peer-reviewed manuscripts at 5 years post-matriculation (median 8 vs 5, p=0.041) and had a faster time to publication of 15 peer-reviewed manuscripts (matched hazard ratio = 2.91, p=0.002). Additionally, program graduates’ publications yielded a significantly higher average H-index (11 vs. 7, p=0.013).
These findings support the effectiveness of formal training programs in clinical and translational science by increasing academic productivity.
We describe the investigation of two temporally coincident illness clusters involving salmonella and Staphylococcus aureus in two states. Cases were defined as gastrointestinal illness following two meal events. Investigators interviewed ill persons. Stool, food and environmental samples underwent pathogen testing. Alabama: Eighty cases were identified. Median time from meal to illness was 5·8 h. Salmonella Heidelberg was identified from 27 of 28 stool specimens tested, and coagulase-positive S. aureus was isolated from three of 16 ill persons. Environmental investigation indicated that food handling deficiencies occurred. Colorado: Seven cases were identified. Median time from meal to illness was 4·5 h. Five persons were hospitalised, four of whom were admitted to the intensive care unit. Salmonella Heidelberg was identified in six of seven stool specimens and coagulase-positive S. aureus in three of six tested. No single food item was implicated in either outbreak. These two outbreaks were linked to infection with Salmonella Heidelberg, but additional factors, such as dual aetiology that included S. aureus or the dose of salmonella ingested may have contributed to the short incubation periods and high illness severity. The outbreaks underscore the importance of measures to prevent foodborne illness through appropriate washing, handling, preparation and storage of food.
Satellite altimetric time series allow high-precision monitoring of ice-sheet mass balance. Understanding elevation changes in these regions is important because outlet glaciers along ice-sheet margins are critical in controlling flow of inland ice. Here we discuss a new airborne altimetry dataset collected as part of the ICECAP (International Collaborative Exploration of the Cryosphere by Airborne Profiling) project over East Antarctica. Using the ALAMO (Airborne Laser Altimeter with Mapping Optics) system of a scanning photon-counting lidar combined with a laser altimeter, we extend the 2003–09 surface elevation record of NASA’s ICESat satellite, by determining cross-track slope and thus independently correcting for ICESat’s cross-track pointing errors. In areas of high slope, cross-track errors result in measured elevation change that combines surface slope and the actual Δz/Δt signal. Slope corrections are particularly important in coastal ice streams, which often exhibit both rapidly changing elevations and high surface slopes. As a test case (assuming that surface slopes do not change significantly) we observe a lack of ice dynamic change at Cook Ice Shelf, while significant thinning occurred at Totten and Denman Glaciers during 2003–09.
The glycaemic and insulin indices assess postprandial glycaemic and insulin response to foods, respectively, which may not reflect the long-term effects of diet on insulin response. We developed and evaluated the validity of four empirical indices to assess the insulinaemic potential of usual diets and lifestyles, using dietary, lifestyle and biomarker data from the Nurses’ Health Study (NHS, n 5812 for hyperinsulinaemia, n 3929 for insulin resistance). The four indices were as follows: the empirical dietary index for hyperinsulinaemia (EDIH) and the empirical lifestyle index for hyperinsulinaemia (ELIH); the empirical dietary index for insulin resistance (EDIR) and the empirical lifestyle index for insulin resistance (ELIR). We entered thirty-nine FFQ-derived food groups in stepwise linear regression models, and defined indices as patterns most predictive of fasting plasma C-peptide, for the hyperinsulinaemia pathway (EDIH and ELIH), and of theTAG:HDL-cholesterol ratio, for the insulin-resistance pathway (EDIR and ELIR). We evaluated the validity of indices in two independent samples from NHS-II and Health Professionals Follow-up Study (HPFS) using multivariable-adjusted linear regression analyses to calculate relative concentrations of biomarkers. The EDIH is comprised of eighteen food groups; thirteen were positively associated with C-peptide and five were inversely associated. The EDIR is comprised of eighteen food groups; ten were positively associated with TAG:HDL-cholesterol and eight were inversely associated. Lifestyle indices had fewer dietary components, and included BMI and physical activity as components. In the validation samples, all indices significantly predicted biomarker concentrations – for example, the relative concentrations of the corresponding biomarkers comparing extreme index quintiles in the HPFS were EDIH, 1·29 (95 % CI 1·22, 1·37); ELIH, 1·78 (95 % CI 1·68, 1·88); EDIR, 1·44 (95 % CI 1·34, 1·55); and ELIR, 2·03 (95 % CI 1·89, 2·19); all Ptrend<0·0001. The robust associations of these novel hypothesis-driven indices with insulin response biomarker concentrations suggest their usefulness in assessing the ability of whole diets and lifestyles to stimulate and/or sustain insulin secretion.
We report the direct detection of cyclic diameter variations in the Mira variable χ Cygni. Interferometric observations made between 1997 July and 1998 September, using the Cambridge Optical Aperture Synthesis Telescope (COAST) indicate periodic changes in the apparent angular diameter with amplitude 45 per-cent of the smallest value.
The measurements were made in a 50 nm bandpass centred on 905 nm, which is only moderately contaminated by molecular absorption features. To assess the effects of atmospheric stratification on the apparent diameter measured in this band, we have also measured near-infrared diameters for a sample of five Miras, in both the J-band (1.3 μm) and Wing's (1971) 1.04 μm band, which is expected to isolate essentially pure continuum emission. We present J-band visibility curves which indicate that the intensity profiles of the stars in the sample differ greatly from each other.
Research on close binary systems has continued at a high level during the past triennium, although the rate of growth is noticeably slower – probably reflecting the cutbacks in funds to which many of us are subject. There have also been changes of emphasis within the field, which are commented on in the pages that follow. These reflect both changing opportunities for observation and the natural development of the subject. In many areas, the time is ripe for a more critical look at ideas that previously seemed adequate.
The field of variable star research has become so broad and the amount of research to be reported on has grown so rapidly that it is a vain hope that a report of this kind, in a very limited space, could cover the whole field of research and could mention all the papers that have been published in the last three years. It is only hoped that this report presents the significant results achieved in the field of the most important aspects of variable star research. Some important subjects (e.g. cataclysmic variables) relevant to the variable star research are reviewed in the reports of other commissions. This is a consequence of the fact that the research has become very complex and the phenomena producing light variability belong to the field of interest of other commissions, too.
The field of variable-star research is so broad that no report of this nature could possibly mention all the papers that have appeared in the last three years. It is hoped, however, that the reviews below include the most important work and identify the most significant trends. This report comprises ten sections on as many different research topics, each written by a different member of Commission 27. In addition there are (in Section 12) three short reports about ongoing activities of the commission. The commission president is very grateful to the authors of the individual contributions who have worked so conscientously.
We report the analysis of 154 hours of nearly continuous high-speed photometric data on the pulsating DB white dwarf (DBV) GD 358 obtained during the Whole Earth Telescope (WET) run of May 1990. The Fourier transform (FT) of the light curve is dominated by power in the range from 1200 – 1700μHz with more than 180 significant peaks in the total transform. We also see significant power at the sums and differences of the dominant frequencies, indicating the importance of nonlinear behavior. We can use this data to obtain an accurate total stellar mass, and surface He layer mass. The implied surface He layer mass, if correct, provides a significant and surprising challenge to stellar evolution theory, as well as the theory of chemical mixing.
White dwarf stars provide important boundary conditions for the understanding of stellar evolution. An adequate understanding of even these simple stars is impossible without detailed knowledge of their interiors. PG1346+082, an interacting binary white dwarf system, provides a unique opportunity to view the interior of one degenerate as it is brought to light in the accretion disk of the second star as the primary strips material from its less massive companion (see Wood et at. 1987).
PG1346+082 is a photometric variable with a four magnitude variation over a four to five day quasi-period. A fast Fourier transform (FFT) of the light curve shows a complex, time-dependent structure of harmonics. PG1346+082 exhibits flickering – the signature of mass transfer. The optical spectra of the system contain weak emission features during minimum and broad absorption at all other times. This could be attributed to pressure broadening in the atmosphere of a compact object, or to a combination of pressure broadening and doppler broadening in a disk surrounding the compact accretor. No hydrogen lines are observed and the spectra are dominated by neutral helium. The spectra also display variable asymmetric line profiles.
Auditory implantation into the inner ear is increasingly performed for a variety of indications. Infective complications are rare, but when they occur they can have devastating consequences.
This paper reports two cases where vestibular sequestration of the bony labyrinth developed following implantation into the middle ear.
To the authors' knowledge, these are the first reported cases where vestibular sequestration has resulted from auditory implant surgery. This paper outlines the radiological changes characteristic of this pathology. It also describes the surgical and conservative treatment options for this condition, challenging the previously accepted belief that affected patients always require aggressive surgical intervention.
In nature, biomolecules guide the formation of hierarchically-ordered, lightweight, inorganic-organic composites such as corals, shells, teeth and bones. M13 bacteriophage has been used to mimic bio-inspired material development due to its rigid, nanoscale rod-like morphology. Liquid-crystalline monolayers of genetically engineered phage have been used to template crystallization of thin layers of inorganic and metallic materials. We have created thin films composed of engineered M13 phage capable of binding inorganic components. We employed both a dip-cast and a drop-cast film fabrication method on both smooth and rough gold, silica and glass casting surfaces to create thin films and 3D structures of various degrees of hierarchical order. We have found the engineered M13 phage and the inorganic mineral significantly affected both film morphology and the mechanical properties of the film. Similarly, film fabrication parameters such as solution chemistry, temperature, and pulling speed affected film properties. Using a calcium phosphate biomineralized 4E phage, film thickness increased linearly with the number of layers/dips in the phage solution. The stiffness of these composites (Young's modulus) were >80 GPa for mineralized, multilayer films. These materials are an order of magnitude stiffer than the biological equivalent collagen. Stiffness, however, does not appear to increase in a multilayer film beyond a saturation point. Ultimately, we have developed a platform for phage-based bio-composites for developing high performance materials.
Designing new materials with well-defined structures and desired functions is a challenge in materials science, especially with nanomaterials. Nature, however, solves design of these materials through a self-assembling, hierarchically ordered process. We have investigated the mechanisms by which the high- aspect ratio and unique surface chemistry of M13 bacteriophage can give rise to increasingly complex, hierarchically ordered, bundled phage structures with a wide range of material applications. A molecular dynamic simulation of the 3-D structure of a 20-nm section of wild type (WT) and mutant phage types were developed based on WT phage crystal structure and ab initio calculations. Simulations of these phage were then used to examine repulsive and attractive forces of the particles in solution. Examination of contact interactions between two WT phage indicated the phage were maximally attracted to each other in a head to tail orientation. A mutant phage (4E) with a higher negative surface charge relative to WT phage also preferentially ordered head to tail in solution. In contrast, a mutant phage (CLP8) with a net positive surface charge had minimal repulsion in a 90° orientation. Understanding the self-assembly process through molecular dynamic simulations and decomposition of fundamental forces driving inter- and intra-strand interactions has provided a qualitative assessment of mechanisms that lead to hierarchical phage bundle structures. Results from simulation agree with experimentally observed patterns from self-assembly. We anticipate using this system to further investigate development of hierarchical structures not only from biological molecules but also from synthetic materials.