1,948 research outputs found

    A Relation Between the Warm Neutral and Ionized Media Observed in the Canadian Galactic Plane Survey

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    We report on a comparison between 21 cm rotation measure (RM) and the optically-thin atomic hydrogen column density (N_HI) measured towards unresolved extragalactic sources in the Galactic plane of the northern sky. HI column densities integrated to the Galactic edge are measured immediately surrounding each of nearly 2000 sources in 1-arcminute 21 cm line data, and are compared to RMs observed from polarized emission of each source. RM data are binned in column-density bins 4x10^20 cm^-2 wide, and one observes a strong relationship between the number of hydrogen atoms in a 1 cm^2 column through the plane and the mean RM along the same line-of-sight and path length. The relationship is linear over one order of magnitude (from 0.8-14x10^21 atoms cm^-2) of column densities, with a constant RM/N_HI -23.2+/-2.3 rad m^-2/10^21 atoms cm^-2, and a positive RM of 45.0+/-13.8 rad m^-2 in the presence of no atomic hydrogen. This slope is used to calculate a mean volume-averaged magnetic field in the 2nd quadrant of ~1.0+/-0.1 micro-Gauss directed away from the Sun, assuming an ionization fraction of 8% (consistent with the WNM). The remarkable consistency between this field and =1.2 micro-Gauss found with the same RM sources and a Galactic model of dispersion measures suggests that electrons in the partially ionized WNM are mainly responsible for pulsar dispersion measures, and thus the partially-ionized WNM is the dominant form of the magneto-ionic interstellar medium.Comment: 6 pages, 4 figures, accepted for publication in the Astrophysical Journal Letters, July 15, 201

    Childhood Depression and Obesity: Role of the Hypothalamic-Pituitary-Adrenal (HPA) Axis Activity

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    This study examined relations between child depression and eating behavior and weight problems, including the role ofbaseline cortisol and cortisol reactivity in these relations. Data were drawn from a larger study, and included 50 children between the ages of6 and 12. Children reported on their depressive symptoms, and children and parents reported on child engagement in external eating, under-eating, over-eating, parental pressure to eat, enjoyment of food, and food and satiety responsiveness. For children exhibiting hypercortisolism, depression was associated with decreased over-eating and food responsiveness. Hypercortisolism was especially important for girls and children later in pubertal development. The reduced appetite and food consumption associated with hypercortisolism and depression may be a manifestation of anhedonic symptoms in childhood

    Serotonin mediated changes in corticotropin releasing factor mRNA expression and feeding behavior isolated to the hypothalamic paraventricular nuclei

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    Fenfluramine reduces hunger and promotes body weight loss by increasing central serotonin (5-HT) signaling. More recently, neuropeptides have been linked to the regulation of feeding behavior, metabolism and body weight. To examine possible interactions between 5-HT and neuropeptides in appetite control, fenfluramine (200 nmol/0.5 μl/side) was administered directly into the hypothalamic paraventricular nuclei (PVN) of male rats. Bilateral fenfluramine produced significant hypophagia and increased expression of PVN corticotropin releasing factor (CRF) mRNA and neuropeptide Y (NPY) mRNA in the arcuate nucleus within the first hour after drug administration. Fenfluramine\u27s effects on feeding behavior and mRNA expression were blocked by PVN injections of a 5-HT1–2 receptor antagonist, metergoline (15 nmol/0.5 μl/side). These data suggest that 5-HT neurons targeting hypothalamic paraventricular CRF neurons may participate in an appetite control circuit for reducing food intake

    Greater understanding of normal hip physical function may guide clinicians in providing targeted rehabilitation programmes

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    Objectives: This study investigated tests of hip muscle strength and functional performance. The specific objectives were to: (i) establish intra- and inter-rater reliability; (ii) compare differences between dominant and non-dominant limbs; (iii) compare agonist and antagonist muscle strength ratios; (iv) compare differences between genders; and (v) examine relationships between hip muscle strength, baseline measures and functional performance. Design: Reliability study and cross-sectional analysis of hip strength and functional performance. Methods: In healthy adults aged 18-50. years, normalised hip muscle peak torque and functional performance were evaluated to: (i) establish intra-rater and inter-rater reliability; (ii) analyse differences between limbs, between antagonistic muscle groups and genders; and (iii) associations between strength and functional performance. Results: Excellent reliability (intra-rater ICC = 0.77-0.96; inter-rater ICC = 0.82-0.95) was observed. No difference existed between dominant and non-dominant limbs. Differences in strength existed between antagonistic pairs of muscles: hip abduction was greater than adduction (p < 0.001) and hip ER was greater than IR (p < 0.001). Men had greater ER strength (p = 0.006) and hop for distance (p < 0.001) than women. Strong associations were observed between measures of hip muscle strength (except hip flexion) and age, height, and functional performance. Conclusions: Deficits in hip muscle strength or functional performance may influence hip pain. In order to provide targeted rehabilitation programmes to address patient-specific impairments, and determine when individuals are ready to return to physical activity, clinicians are increasingly utilising tests of hip strength and functional performance. This study provides a battery of reliable, clinically applicable tests which can be used for these purposes

    Forecasting the spread of raccoon rabies using a purpose-specific group decisionmaking process

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    The Centers for Disease Control (CDC) and USDA Wildlife Services (WS) have been involved in an oral rabies vaccination (ORV) program for raccoons (Procyon lotor) that has slowed the westward spread of raccoon rabies. The objective of this study was to forecast the spread of the disease if an ORV zone was not maintained. A group decision-making process was designed to address the forecasting problem and was implemented using a group of 15 experts and 4 support personnel at a meeting at the USDA National Wildlife Research Center. Ten expansion regions were constructed that described the spread of disease at 2-year intervals. This forecast may provide for more accurate cost-benefit analysis of the ORV barrier

    Complex host genetics influence the microbiome in inflammatory bowel disease

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    Background: Human genetics and host-associated microbial communities have been associated independently with a wide range of chronic diseases. One of the strongest associations in each case is inflammatory bowel disease (IBD), but disease risk cannot be explained fully by either factor individually. Recent findings point to interactions between host genetics and microbial exposures as important contributors to disease risk in IBD. These include evidence of the partial heritability of the gut microbiota and the conferral of gut mucosal inflammation by microbiome transplant even when the dysbiosis was initially genetically derived. Although there have been several tests for association of individual genetic loci with bacterial taxa, there has been no direct comparison of complex genome-microbiome associations in large cohorts of patients with an immunity-related disease. Methods: We obtained 16S ribosomal RNA (rRNA) gene sequences from intestinal biopsies as well as host genotype via Immunochip in three independent cohorts totaling 474 individuals. We tested for correlation between relative abundance of bacterial taxa and number of minor alleles at known IBD risk loci, including fine mapping of multiple risk alleles in the Nucleotide-binding oligomerization domain-containing protein 2 (NOD2) gene exon. We identified host polymorphisms whose associations with bacterial taxa were conserved across two or more cohorts, and we tested related genes for enrichment of host functional pathways. Results: We identified and confirmed in two cohorts a significant association between NOD2 risk allele count and increased relative abundance of Enterobacteriaceae, with directionality of the effect conserved in the third cohort. Forty-eight additional IBD-related SNPs have directionality of their associations with bacterial taxa significantly conserved across two or three cohorts, implicating genes enriched for regulation of innate immune response, the JAK-STAT cascade, and other immunity-related pathways. Conclusions: These results suggest complex interactions between genetically altered host functional pathways and the structure of the microbiome. Our findings demonstrate the ability to uncover novel associations from paired genome-microbiome data, and they suggest a complex link between host genetics and microbial dysbiosis in subjects with IBD across independent cohorts. Electronic supplementary material The online version of this article (doi:10.1186/s13073-014-0107-1) contains supplementary material, which is available to authorized users
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