Radio continuum observations of local star-forming galaxies using the Caltech Continuum Backend on the Green Bank Telescope

We observed radio continuum emission in 27 local (D < 70 Mpc) star-forming galaxies with the Robert C. Byrd Green Bank Telescope between 26 GHz and 40 GHz using the Caltech Continuum Backend. We obtained detections for 22 of these galaxies at all four sub-bands and four more marginal detections by taking the average flux across the entire bandwidth. This is the first detection (full or marginal) at these frequencies for 22 of these galaxies. We fit spectral energy distributions (SEDs) for all of the four-sub-band detections. For 14 of the galaxies, SEDs were best fit by a combination of thermal free-free and nonthermal synchrotron components. Eight galaxies with four-sub-band detections had steep spectra that were only fit by a single nonthermal component. Using these fits, we calculated supernova rates, total number of equivalent O stars, and star formation rates within each ~23 arcsecond beam. For unresolved galaxies, these physical properties characterize the galaxies' recent star formation on a global scale. We confirm that the radio-far-infrared correlation holds for the unresolved galaxies' total 33 GHz flux regardless of their thermal fractions, though the scatter on this correlation is larger than that at 1.4 GHz. In addition, we found that for the unresolved galaxies, there is an inverse relationship between the ratio of 33 GHz flux to total far-infrared flux and the steepness of the galaxy's spectral index between 1.4 GHz and 33 GHz. This relationship could be an indicator of the timescale of the observed episode of star formation.Comment: 36 pages, 9 figures; accepted for publication in ApJ. First and second author affiliation updated to reflect departmental name chang

Genomic and Transcriptomic Alterations Associated with STAT3 Activation in Head and Neck Cancer.

BackgroundHyperactivation of STAT3 via constitutive phosphorylation of tyrosine 705 (Y705) is common in most human cancers, including head and neck squamous carcinoma (HNSCC). STAT3 is rarely mutated in cancer and the (epi)genetic alterations that lead to STAT3 activation are incompletely understood. Here we used an unbiased approach to identify genomic and epigenomic changes associated with pSTAT3(Y705) expression using data generated by The Cancer Genome Atlas (TCGA).Methods and findingsMutation, mRNA expression, promoter methylation, and copy number alteration data were extracted from TCGA and examined in the context of pSTAT3(Y705) protein expression. mRNA expression levels of 1279 genes were found to be associated with pSTAT3(705) expression. Association of pSTAT3(Y705) expression with caspase-8 mRNA expression was validated by immunoblot analysis in HNSCC cells. Mutation, promoter hypermethylation, and copy number alteration of any gene were not significantly associated with increased pSTAT3(Y705) protein expression.ConclusionsThese cumulative results suggest that unbiased approaches may be useful in identifying the molecular underpinnings of oncogenic signaling, including STAT3 activation, in HNSCC. Larger datasets will likely be necessary to elucidate signaling consequences of infrequent alterations

Inducing Incentive Sensitization of Exercise Reinforcement Among Adults Who Do Not Regularly Exercise—A Randomized Controlled Trial

Background Increasing exercise reinforcement, or decreasing sedentary reinforcement, may reduce sedentary activity and promote habitual exercise. Repeated exposures to a reinforcer may increase its reinforcing value (i.e., incentive sensitization). It is not yet known whether incentive sensitization occurs for exercise or factors associated with incentive sensitization for exercise reinforcement. The purpose was to determine whether exercise exposures increase exercise reinforcement relative to a sedentary alternative and whether this sensitization of exercise reinforcement would alter physical or sedentary behavior. This work also determined whether exercise dose, intensity, and preference and tolerance for exercise intensity were associated with incentive sensitization of exercise. Methods 104 sedentary men and women were randomized to exercise training groups with 89 completing the study. Groups included exercise exposures of 150 (n = 35) or 300 kcal/session (n = 34), 3 sessions/week for 6 weeks, or a non-exercise control group (n = 35). Assessments for exercise and sedentary behavior reinforcement (primary dependent variables) and activity and tolerance for exercise intensity were performed at baseline (week 0), post training (week 6), and post washout (week 10). Results The control group reduced (P = 0.022) relative reinforcing value of exercise, such that the 150 kcal group had a greater relative reinforcing value of exercise after the exercise treatment 150 kcal: 0.69 ± 0.07 to 0.74 ± 0.07; 300 kcal: 0.72 ± 0.07 to 0.63 ± 0.08, control: 0.72 ± 0.07 to 0.57 ± 0.08 mean ± SE. Increases in tolerance for exercise intensity discomfort were associated with increases in relative reinforcing value of exercise. Sedentary behavior reinforcement decreased in both exercise groups (150 kcal: 5.4 ± 4.3 to 1.8 ± 1.3; 300 kcal: 5.4 ± 4.3 to 3.1 ± 2.4, P \u3c 0.05), but remained unchanged in the control group (5.1 ± 4.0 to 6.1 ± 4.9, P \u3e 0.05). Sedentary activity decreased baseline to post-training in the 300 kcal group (546.5 ± 10.7 to 503.8 ± 11.8 minutes, P \u3c 0.01). Conclusion Small amounts of regular exercise may reduce the reinforcing value sedentary behavior. The process of incentive sensitization of exercise may include reducing the reinforcing value of competing sedentary activities. Developing tolerance to exercise discomfort of exercise may be critical to increasing exercise reinforcement

Increasing the Reinforcing Value of Exercise in Overweight Adults

Objectives: This study determined whether a moderate- or high-dose exercise program increases exercise reinforcement. Increasing the relative reinforcing value of exercise (RRVexercise; i.e., incentive sensitization of exercise) may increase the usual physical activity (PA) participation. Preference and/or tolerance for the intensity of exercise was also assessed. Design: Sedentary men and women (body mass index, BMI: 25–35 kg/m2) were randomized into parallel exercise training groups expending either 300 (n = 18) or 600 (n = 18) kcal/exercise session, five sessions/week, for 12 weeks. Methods: The RRVexercise was determined by how much work was performed for exercise relative to a sedentary alternative in a progressive ratio schedule task. Preference and tolerance for exercise intensity were determined by questionnaire. Results: RRVexercise increased (P \u3c 0.05) in both groups. Exercise reinforcement, defined as the amount of work completed for exercise without taking sedentary activity into account, increased (P \u3c 0.01) in the 600 kcal group only. Preference and tolerance for exercise intensity increased (P \u3c 0.01) in both groups, which predicted increases in RRVexercise. Conclusion: Expending 300 or 600 kcal, 5 days/week increases RRVexercise, while 600 kcal, 5 days/week may be needed to increase exercise reinforcement

Variable Hard X-ray Emission from the Candidate Accreting Black Hole in Dwarf Galaxy Henize 2-10

We present an analysis of the X-ray spectrum and long-term variability of the nearby dwarf starburst galaxy Henize 2-10. Recent observations suggest that this galaxy hosts an actively accreting black hole with mass ~10^6 M_sun. The presence of an AGN in a low-mass starburst galaxy marks a new environment for active galactic nuclei (AGNs), with implications for the processes by which "seed" black holes may form in the early Universe. In this paper, we analyze four epochs of X-ray observations of Henize 2-10, to characterize the long-term behavior of its hard nuclear emission. We analyze observations with Chandra from 2001 and XMM-Newton from 2004 and 2011, as well as an earlier, less sensitive observation with ASCA from 1997. Based on detailed analysis of the source and background, we find that the hard (2-10 keV) flux of the putative AGN has decreased by approximately an order of magnitude between the 2001 Chandra observation and exposures with XMM-Newton in 2004 and 2011. The observed variability confirms that the emission is due to a single source. It is unlikely that the variable flux is due to a supernova or ultraluminous X-ray source, based on the observed long-term behavior of the X-ray and radio emission, while the observed X-ray variability is consistent with the behavior of well-studied AGNs.Comment: 7 pages, 4 figures, 2 tables; accepted for publication in Ap

Evidence for strain-specific exometabolomic responses of the coccolithophore Emiliania huxleyi to grazing by the dinoflagellate oxyrrhis marina

© The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Frontiers in Marine Science 3 (2016): 1, doi:10.3389/fmars.2016.00001.The coccolithophore Emiliania huxleyi forms massive blooms and plays a critical role in global elemental cycles, sequestering significant amounts of atmospheric carbon dioxide on geological time scales via production of calcium carbonate coccoliths and emitting dimethyl sulfoniopropionate (DMSP), which has the potential for increasing atmosph-eric albedo. Because grazing in pelagic systems is a major top-down force structuring microbial communities, the influence of grazers on E. huxleyi populations has been of interest to researchers. Roles of DMSP (and related metabolites) in interactions between E. huxleyi and protist grazers have been investigated, however, little is known about the release of other metabolites that may influence, or be influenced by, such grazing interactions. We used high-resolution mass spectrometry in an untargeted approach to survey the suite of low molecular weight compounds released by four different E. huxleyi strains in response to grazing by the dinoflagellate Oxyrrhis marina. Overall, a strikingly small number of metabolites were detected from E. huxleyi and O. marina cells, but these were distinctly informative to construct metabolic footprints. At most, E. huxleyi strains shared 25% of released metabolites. Furthermore, there appeared to be no unified metabolic response in E. huxleyi strains to grazing; rather, these responses were strain specific. Concentrations of several metabolites also positively correlated with grazer activities, including grazing, ingestion, and growth rates; however, no single metabolite responded uniformly across all strains of E. huxleyi tested. Regardless, grazing clearly transformed the constituents of dissolved organic matter produced by these marine microbes. This study addresses several technical challenges, and presents a platform to further study the influence of chemical cues in aquatic systems and demonstrates the impact of strain diversity and grazing on the complexity of dissolved organic matter in marine systems.Funding for this work was provided by the Gordon and Betty Moore Foundation, Grant #3301 awarded to A Vardi, BAS. Van Mooy, K Bidle, MJ, and TM. Additional funding for this work was provided by an award from the Flatley Discovery Lab to TM

Global Properties of Neutral Hydrogen in Compact Groups

Compact groups of galaxies provide a unique environment to study the evolution of galaxies amid frequent gravitational encounters. These nearby groups have conditions similar to those in the earlier universe when galaxies were assembled and give us the opportunity to witness hierarchical formation in progress. To understand how the compact group environment affects galaxy evolution, we examine the gas and dust in these groups. We present new single-dish GBT neutral hydrogen (HI) observations of 30 compact groups and define a new way to quantify the group HI content as the HI-to-stellar mass ratio of the group as a whole. We compare the HI content with mid-IR indicators of star formation and optical [g-r] color to search for correlations between group gas content and star formation activity of individual group members. Quiescent galaxies tend to live in HI-poor groups, and galaxies with active star formation are more commonly found in HI-rich groups. Intriguingly, we also find "rogue" galaxies whose star formation does not correlate with group HI content. In particular, we identify three galaxies (NGC 2968 in RSCG 34, KUG 1131+202A in RSCG 42, and NGC 4613 in RSCG 64) whose mid-IR activity is discrepant with the HI. We speculate that this mismatch between mid-IR activity and HI content is a consequence of strong interactions in this environment that can strip HI from galaxies and abruptly affect star-formation. Ultimately, characterizing how and on what timescales the gas is processed in compact groups will help us understand the interstellar medium in complex, dense environments similar to the earlier Universe.Comment: Accepted to A

Genetic Variations in the Dopamine Reward System Influence Exercise Reinforcement and Tolerance for Exercise Intensity

Background: Exercise is a reinforcing behavior and finding exercise highly reinforcing is characteristic of habitual exercisers. Genotypes related to dopamine metabolism moderate the reinforcing value of behaviors, but genetic moderators of exercise reinforcement have not been established. Purpose: Determine whether singular nucleotide polymorphisms (SNPs) that moderate central reward pathways and pain neurotransmission are associated with exercise reinforcement, tolerance for exercise intensity, and usual physical activity. Methods: Adults (n = 178) were measured for the reinforcing value of exercise relative to sedentary activities (RRVexercise), minutes of moderate-to-vigorous physical activity (MVPA) and completed the Preference for and Tolerance of the Intensity of Exercise Questionnaire. Genotyping of 23 SNPs known to influence central dopamine tone, pain, or physical activity was performed. ANOVA tested differences in RRVexercise, tolerance, and MVPA among genotype groups. Linear regression controlling for BMI, sex, and liking of exercise was used to further predict the association of genotype on RRVexercise, tolerance, and MVPA. Results: Having at least one copy of the G allele for the DRD2/ANKK1 polymorphism (rs1800497) conferred greater RRVexercise. Greater tolerance for exercise intensity was observed among those homozygous for the T allele for the CNR1 polymorphism (rs6454672), had at least one copy of the G allele for the GABRG3 polymorphism (rs8036270), or had at least one copy of the T allele for the LPR polymorphism (rs12405556). Homozygous individuals for the T allele at rs6454672 exhibited greater MVPA. Conclusion: Similar to other reinforcing behaviors, there is a genetic contribution to exercise reinforcement, tolerance for exercise intensity, and MVPA