922 research outputs found

    The magnetic environment of the Orion-Eridanus superbubble as revealed by Planck

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    Using the 353-GHz polarization observations by the Planck satellite we characterize the magnetic field in the Orion-Eridanus superbubble, a nearby expanding structure that spans more than 1600 square degrees in the sky. We identify a region of both low dispersion of polarization orientations and high polarization fraction associated with the outer wall of the superbubble identified in the most recent models of the large-scale shape of the region. We use the Davis-Chandrasekhar-Fermi method to derive plane-of-the-sky magnetic field strengths of tens of microGauss toward the southern edge of the bubble. The comparison of these values with existing Zeeman splitting observations of HI in emission suggests that the large-scale magnetic field in the region was primarily shaped by the expanding superbubble.Comment: 7 pages, 8 figures. Accepted for publication as a Letter in A&A, section 1. Letters to the Editor (08/12/2017

    Kinematics of dense gas in the L1495 filament

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    We study the kinematics of the dense gas of starless and protostellar cores traced by the N2D+(2-1), N2H+(1-0), DCO+(2-1), and H13CO+(1-0) transitions along the L1495 filament and the kinematic links between the cores and the surrounding molecular cloud. We measure velocity dispersions, local and total velocity gradients and estimate the specific angular momenta of 13 dense cores in the four transitions using the on-the-fly observations with the IRAM 30 m antenna. To study a possible connection to the filament gas, we use the fit results of the C18O(1-0) survey performed by Hacar et al. (2013). All cores show similar properties along the 10 pc-long filament. N2D+(2-1) shows the most centrally concentrated structure, followed by N2H+(1-0) and DCO+(2-1), which show similar spatial extent, and H13CO+(1-0). The non-thermal contribution to the velocity dispersion increases from higher to lower density tracers. The change of magnitude and direction of the total velocity gradients depending on the tracer used indicates that internal motions change at different depths within the cloud. N2D+ and N2H+ show smaller gradients than the lower density tracers DCO+ and H13CO+, implying a loss of specific angular momentum at small scales. At the level of cloud-core transition, the core's external envelope traced by DCO+ and H13CO+ is spinning up, consistent with conservation of angular momentum during core contraction. C18O traces the more extended cloud material whose kinematics is not affected by the presence of dense cores. The decrease in specific angular momentum towards the centres of the cores shows the importance of local magnetic fields to the small scale dynamics of the cores. The random distributions of angles between the total velocity gradient and large scale magnetic field suggests that the magnetic fields may become important only in the high density gas within dense cores.Comment: Accepted for publication in A&A. The abstract is shortene

    Mid-J CO Shock Tracing Observations of Infrared Dark Clouds I

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    Infrared dark clouds (IRDCs) are dense, molecular structures in the interstellar medium that can harbour sites of high-mass star formation. IRDCs contain supersonic turbulence, which is expected to generate shocks that locally heat pockets of gas within the clouds. We present observations of the CO J = 8-7, 9-8, and 10-9 transitions, taken with the Herschel Space Observatory, towards four dense, starless clumps within IRDCs (C1 in G028.37+00.07, F1 and F2 in G034.43+0007, and G2 in G034.77-0.55). We detect the CO J = 8-7 and 9-8 transitions towards three of the clumps (C1, F1, and F2) at intensity levels greater than expected from photodissociation region (PDR) models. The average ratio of the 8-7 to 9-8 lines is also found to be between 1.6 and 2.6 in the three clumps with detections, significantly smaller than expected from PDR models. These low line ratios and large line intensities strongly suggest that the C1, F1, and F2 clumps contain a hot gas component not accounted for by standard PDR models. Such a hot gas component could be generated by turbulence dissipating in low velocity shocks.Comment: 14 pages, 8 figures, 5 tables, accepted by A&A, minor updates to match the final published versio

    Disordered speech disrupts conversational entrainment: a study of acoustic-prosodic entrainment and communicative success in populations with communication challenges

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    Conversational entrainment, a pervasive communication phenomenon in which dialogue partners adapt their behaviors to align more closely with one another, is considered essential for successful spoken interaction. While well-established in other disciplines, this phenomenon has received limited attention in the field of speech pathology and the study of communication breakdowns in clinical populations. The current study examined acoustic-prosodic entrainment, as well as a measure of communicative success, in three distinctly different dialogue groups: (i) healthy native vs. healthy native speakers (Control), (ii) healthy native vs. foreign-accented speakers (Accented), and (iii) healthy native vs. dysarthric speakers (Disordered). Dialogue group comparisons revealed significant differences in how the groups entrain on particular acoustic–prosodic features, including pitch, intensity, and jitter. Most notably, the Disordered dialogues were characterized by significantly less acoustic-prosodic entrainment than the Control dialogues. Further, a positive relationship between entrainment indices and communicative success was identified. These results suggest that the study of conversational entrainment in speech pathology will have essential implications for both scientific theory and clinical application in this domain

    Zooplankton abundance and distribution at Minicoy lagoon, Lakshadweep

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    The environmental parameters such as water temperature, salinity, cloud cover wind foree, rainfall and tide that influence the distribution and abundance of zooplankton at two sites in Minicoy lagoon were siudied from August 1994 to July 1995. The northern part of the lagoon with more live corals had better abundance of ooplankton when compared to the southern area, Zooplankton from different lagoon bottoms namely coralline, sandy and seagrass bed did not how significant variation between sites. Copepods, 8mphipods and decapod larvae were the dominant groups

    Prevalence of Non - Communicable Diseases and their Risk Factors in Tribal South India: A Community Based Cross Sectional study

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    BACKGROUND : Non communicable diseases are the leading cause of morbidity and mortality in India. Cardio vascular disease accounts for majority of non communicable diseases related deaths. This cross-sectional study was conducted among the residents of Jawadhu hills which is situated in Vellore and Tiruvannamalai districts of Tamil Nadu. The main objective of this study was to estimate the prevalence of diabetes mellitus, hypertension, dyslipidaemia and metabolic syndrome and their risk factors among the residents of Jawadhu hills aged between 30-60 years. METHODS : This study was conducted in 14 villages of Jawadhu hills in Tiruvannamalai district. Two stage cluster sampling method was used. Villages were selected by probability proportionate to size sampling. Consecutive Households were selected from village starting point in clockwise direction as per the algorithm until the required sample size was obtained. Totally 480 people (males-225 & females-255) were surveyed from February 2016 to July 2016 using modified WHO-STEPS questionnaire. Socio demographic factors, behavioural and metabolic risk factors and anthrometric measures were collected. Fasting and post prandial (2 hour) blood glucose were collected for 480 people by using glucometer. Among the subset of 138 people (one participant from alternate household) fasting lipid samples were collected. RESULTS: Of the subjects (480) studied, 3.3% had diabetes mellitus,7.6% had prediabetes, 17.7% had hypertension. Among the sub group of 138 people, 51.5% had abnormalities in any one of the lipid parameters. 16.7% of the study population had hypercholestremia, 24.6% had hyper triglyceridemia, 26.8% had low HDL, 18.1% had high LDL, 10.8% had high total cholesterol/HDL ratio (>4.5) and 12.3% had metabolic syndrome. Out of 480 people, 11.7% had low physical activity (less than the WHO recommended). Using Asian cutoff, prevalence of obesity, overweight and central obesity were 20%, 4.8% and 9.8% respectively. Most of the participants were from low socio economic status. Alcohol use and smoking is common among men (72.9%and 64% respectively). In the multivariate analysis, overweight was significantly associated with hypertension and dyslipidaemia. Low levels of physical activity and obesity were associated with and metabolic syndrome. CONCLUSION : Prevalence of diabetes in this tribal population is low (3.3%). However, 51.5% had dyslipidaemia and 17.7% had hypertension. High prevalence of behavioural and metabolic risk factors calls for urgent intervention

    Molecular dissection of translation initiation factor IF2. Evidence for two structural and functional domains.

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    By means of limited proteolysis of Bacillus stearothermophilus initiation factor IF2 and genetic manipulation of its structural gene, infB, we have been able to produce (or hyperproduce) and purify two polypeptide fragments corresponding to two structurally and functionally separate domains of the protein. The first is the G-domain (approximately 41 kDa), which makes up the central part of the molecule and contains the conserved structural elements found in all GTP/GDP-binding sites of G-proteins. This domain is resistant to proteolysis in the presence of GTP or GDP, retains the capacity to interact with the 50 S subunit, binds weakly to the 30 S subunit, and displays ribosome-dependent GTPase activity with an approximately 2-fold higher Km for GTP and the same Vmax as compared with intact IF2. The second is the C-domain (approximately 24 kDa), which corresponds to the COOH-terminal part of IF2 and constitutes an extraordinarily compact domain containing the fMet-tRNA binding site of IF2. In spite of its negligible affinity for the ribosomes, the C-domain weakly stimulates the ribosomal binding of fMet-tRNA, presumably by affecting the conformation of the initiator tRNA molecule