Surface Gravities for 228 M, L, and T Dwarfs in the NIRSPEC Brown Dwarf Spectroscopic Survey

We combine 131 new medium-resolution (R~2000) J-band spectra of M, L, and T dwarfs from the Keck NIRSPEC Brown Dwarf Spectroscopic Survey (BDSS) with 97 previously published BDSS spectra to study surface-gravity-sensitive indices for 228 low-mass stars and brown dwarfs spanning spectral types M5-T9. Specifically, we use an established set of spectral indices to determine surface gravity classifications for all M6-L7 objects in our sample by measuring equivalent widths (EW) of the K I lines at 1.1692, 1.1778, 1.2529 um, and the 1.2 um FeHJ absorption index. Our results are consistent with previous surface gravity measurements, showing a distinct double peak - at ~L5 and T5 - in K I EW as a function of spectral type. We analyze K I EWs of 73 objects of known ages and find a linear trend between log(Age) and EW. From this relationship, we assign age ranges to the very low gravity, intermediate gravity, and field gravity designations for spectral types M6-L0. Interestingly, the ages probed by these designations remain broad, change with spectral type, and depend on the gravity sensitive index used. Gravity designations are useful indicators of the possibility of youth, but current datasets cannot be used to provide a precise age estimate.Comment: 33 pages, 13 figures, ApJ in pres

Microsatellite markers for the biogeographically enigmatic sandmyrtle (Kalmia buxifolia, Phyllodoceae: Ericaceae)

Premise: Microsatellite markers were developed for sandmyrtle, Kalmia buxifolia (Ericaceae), to facilitate phylogeographic studies in this taxon and possibly many of its close relatives. Methods and Results: Forty‐eight primer pairs designed from paired‐end Illumina MiSeq data were screened for robust amplification. Sixteen pairs were amplified again, but with fluorescently labeled primers to facilitate genotyping. Resulting chromatograms were evaluated for variability using three populations from Tennessee, North Carolina, and New Jersey, USA. Eleven primer pairs were reliable and polymorphic (mean 3.92 alleles), one was reliable but monomorphic, and four were not reliable. The markers exhibited lower heterozygosity (mean 0.246) than expected (mean 0.464). Cross‐amplification in the remaining nine Kalmia species exhibited a phylogenetic pattern, suggesting broad applicability of the markers across the genus. Conclusions: These microsatellite markers will be useful in population genetics and species boundaries studies of K. buxifolia, K. procumbens, and likely all other Kalmia species.publishedVersio

The NIRSPEC Brown Dwarf Spectroscopic Survey II: High-Resolution J-Band Spectra of M, L and T Dwarfs

We present a sequence of high resolution (R~20,000 or 15 km/s) infrared spectra of stars and brown dwarfs spanning spectral types M2.5 to T6. Observations of 16 objects were obtained using eight echelle orders to cover part of the J-band from 1.165-1.323 micron with NIRSPEC on the Keck II telescope. By comparing opacity plots and line lists, over 200 weak features in the J-band are identified with either FeH or H2O transitions. Absorption by FeH attains maximum strength in the mid-L dwarfs, while H2O absorption becomes systematically stronger towards later spectral types. Narrow resolved features broaden markedly after the M to L transition. Our high resolution spectra also reveal that the disappearance of neutral Al lines at the boundary between M and L dwarfs is remarkably abrupt, presumably because of the formation of grains. Neutral Fe lines can be traced to mid-L dwarfs before Fe is removed by condensation. The neutral potassium (K I) doublets that dominate the J-band have pressure broadened wings that continue to broaden from ~50 km/s (FWHM) at mid-M to ~500 km/s at mid-T. In contrast however, the measured pseudo-equivalent widths of these same lines reach a maximum in the mid-L dwarfs. The young L2 dwarf, G196-3B, exhibits narrow potassium lines without extensive pressure-broadened wings, indicative of a lower gravity atmosphere. Kelu-1AB, another L2, has exceptionally broad infrared lines, including FeH and H2O features, confirming its status as a rapid rotator. In contrast to other late T objects, the peculiar T6 dwarf 2MASS 0937+29 displays a complete absence of potassium even at high resolution, which may be a metallicity effect or a result of a cooler, higher-gravity atmosphere.Comment: 53 pages, 21 figures, data will be available at http://www.astro.ucla.edu/~mclean/BDSSarchive

Microsatellite markers for the biogeographically enigmatic sandmyrtle (Kalmia buxifolia, Phyllodoceae: Ericaceae)

Premise: Microsatellite markers were developed for sandmyrtle, Kalmia buxifolia (Ericaceae), to facilitate phylogeographic studies in this taxon and possibly many of its close relatives. Methods and Results: Forty‐eight primer pairs designed from paired‐end Illumina MiSeq data were screened for robust amplification. Sixteen pairs were amplified again, but with fluorescently labeled primers to facilitate genotyping. Resulting chromatograms were evaluated for variability using three populations from Tennessee, North Carolina, and New Jersey, USA. Eleven primer pairs were reliable and polymorphic (mean 3.92 alleles), one was reliable but monomorphic, and four were not reliable. The markers exhibited lower heterozygosity (mean 0.246) than expected (mean 0.464). Cross‐amplification in the remaining nine Kalmia species exhibited a phylogenetic pattern, suggesting broad applicability of the markers across the genus. Conclusions: These microsatellite markers will be useful in population genetics and species boundaries studies of K. buxifolia, K. procumbens, and likely all other Kalmia species.publishedVersio

Test-Retest Reliability of the Repetitive Step Test in Community Dwelling Older Adults

Each year one in every three adults over the age of 65 experience a fall resulting in serious injury and in some instances death. In this population, falling injuries are the leading cause of death and are associated with the greatest number of nonfatal injuries and trauma hospital admissions. Since balance and muscle performance decreases as one ages, it is vitally important to assess these factors as part of a comprehensive strategy to monitor and predict fall risk. Previous data analysis of the Repetitive Step Test (RST) has shown that there is a significant performance difference between non-fallers and recurrent fallers in particular stepping conditions, and that significant inter-limb differences exist in non-fallers.https://ecommons.udayton.edu/dpt_symposium/1033/thumbnail.jp

Functional replacement of myostatin with GDF-11 in the germline of mice.

BACKGROUND: Myostatin (MSTN) is a transforming growth factor-ß superfamily member that acts as a major regulator of skeletal muscle mass. GDF-11, which is highly related to MSTN, plays multiple roles during embryonic development, including regulating development of the axial skeleton, kidneys, nervous system, and pancreas. As MSTN and GDF-11 share a high degree of amino acid sequence identity, behave virtually identically in cell culture assays, and utilize similar regulatory and signaling components, a critical question is whether their distinct biological functions result from inherent differences in their abilities to interact with specific regulatory and signaling components or whether their distinct biological functions mainly reflect their differing temporal and spatial patterns of expression. METHODS: We generated and characterized mice in which we precisely replaced in the germline the portion of the Mstn gene encoding the mature C-terminal peptide with the corresponding region of Gdf11. RESULTS: In mice homozygous for the knock-in allele, all of the circulating MSTN protein was replaced with GDF-11, resulting in ~ 30-40-fold increased levels of circulating GDF-11. Male mice homozygous for the knock-in allele had slightly decreased muscle weights, slightly increased weight gain in response to a high-fat diet, slightly increased plasma cholesterol and HDL levels, and significantly decreased bone density and bone mass, whereas female mice were mostly unaffected. CONCLUSIONS: GDF-11 appears to be capable of nearly completely functionally replacing MSTN in the control of muscle mass. The developmental and physiological consequences of replacing MSTN with GDF-11 are strikingly limited

A Multicenter Examination and Strategic Revisions of the Yale Global Tic Severity Scale

Objective To examine the internal consistency and distribution of the Yale Global Tic Severity Scale (YGTSS) scores to inform modification of the measure. Methods This cross-sectional study included 617 participants with a tic disorder (516 children and 101 adults), who completed an age-appropriate diagnostic interview and the YGTSS to evaluate tic symptom severity. The distributions of scores on YGTSS dimensions were evaluated for normality and skewness. For dimensions that were skewed across motor and phonic tics, a modified Delphi consensus process was used to revise selected anchor points. Results Children and adults had similar clinical characteristics, including tic symptom severity. All participants were examined together. Strong internal consistency was identified for the YGTSS Motor Tic score (α = 0.80), YGTSS Phonic Tic score (α = 0.87), and YGTSS Total Tic score (α = 0.82). The YGTSS Total Tic and Impairment scores exhibited relatively normal distributions. Several subscales and individual item scales departed from a normal distribution. Higher scores were more often used on the Motor Tic Number, Frequency, and Intensity dimensions and the Phonic Tic Frequency dimension. By contrast, lower scores were more often used on Motor Tic Complexity and Interference, and Phonic Tic Number, Intensity, Complexity, and Interference. Conclusions The YGTSS exhibits good internal consistency across children and adults. The parallel findings across Motor and Phonic Frequency, Complexity, and Interference dimensions prompted minor revisions to the anchor point description to promote use of the full range of scores in each dimension. Specific minor revisions to the YGTSS Phonic Tic Symptom Checklist were also proposed

Parental Programming of Offspring Health: The Intricate Interplay between Diet, Environment, Reproduction and Development

As adults, our health can be influenced by a range of lifestyle and environmental factors, increasing the risk for developing a series of non-communicable diseases such as type 2 diabetes, heart disease and obesity. Over the past few decades, our understanding of how our adult health can be shaped by events occurring before birth has developed into a well-supported concept, the Developmental Origins of Health and Disease (DOHaD). Supported by epidemiological data and experimental studies, specific mechanisms have been defined linking environmental perturbations, disrupted fetal and neonatal development and adult ill-health. Originally, such studies focused on the significance of poor maternal health during pregnancy. However, the role of the father in directing the development and well-being of his offspring has come into recent focus. Whereas these studies identify the individual role of each parent in shaping the long-term health of their offspring, few studies have explored the combined influences of both parents on offspring well-being. Such understanding is necessary as parental influences on offspring development extend beyond the direct genetic contributions from the sperm and oocyte. This article reviews our current understanding of the parental contribution to offspring health, exploring some of the mechanisms linking parental well-being with gamete quality, embryo development and offspring health