1,171 research outputs found

    Characterisation of the Mopra Radio Telescope at 16--50 GHz

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    We present the results of a programme of scanning and mapping observations of astronomical masers and Jupiter designed to characterise the performance of the Mopra Radio Telescope at frequencies between 16-50 GHz using the 12-mm and 7-mm receivers. We use these observations to determine the telescope beam size, beam shape and overall telescope beam efficiency as a function of frequency. We find that the beam size is well fit by λ\lambda/DD over the frequency range with a correlation coefficient of ~90%. We determine the telescope main beam efficiencies are between ~48-64% for the 12-mm receiver and reasonably flat at ~50% for the 7-mm receiver. Beam maps of strong H2_2O (22 GHz) and SiO masers (43 GHz) provide a means to examine the radial beam pattern of the telescope. At both frequencies the radial beam pattern reveals the presence of three components, a central `core', which is well fit by a Gaussian and constitutes the telescopes main beam, and inner and outer error beams. At both frequencies the inner and outer error beams extend out to approximately 2 and 3.4 times the full-width half maximum of the main beam respectively. Sources with angular sizes a factor of two or more larger than the telescope main beam will couple to the main and error beams, and therefore the power contributed by the error beams needs to be considered. From measurements of the radial beam power pattern we estimate the amount of power contained in the inner and outer error beams is of order one-fifth at 22 GHz rising slightly to one-third at 43 GHz.Comment: Accepted for publication in PAS

    The RMS Survey: Ammonia and water maser analysis of massive star forming regions

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    The Red MSX Source (RMS) survey has identified a sample of ~1200 massive young stellar objects (MYSOs), compact and ultra compact HII regions from a sample of ~2000 MSX and 2MASS colour selected sources. We have used the 100 m Green Bank telescope to search for 22-24 GHz water maser and ammonia (1,1), (2,2) and (3,3) emission towards ~600 RMS sources located within the northern Galactic plane. We have identified 308 H2O masers which corresponds to an overall detection rate of ~50%. Abridged: We detect ammonia emission towards 479 of these massive young stars, which corresponds to ~80%. Ammonia is an excellent probe of high density gas allowing us to measure key parameters such as gas temperatures, opacities, and column densities, as well as providing an insight into the gas kinematics. The average kinetic temperature, FWHM line width and total NH3 column density for the sample are approximately 22 K, 2 km/s and 2x10^{15} cm^{-2}, respectively. We find that the NH3 (1,1) line width and kinetic temperature are correlated with luminosity and finding no underlying dependence of these parameters on the evolutionary phase of the embedded sources, we conclude that the observed trends in the derived parameters are more likely to be due to the energy output of the central source and/or the line width-clump mass relationship. The velocities of the peak H2O masers and the NH3 emission are in excellent agreement with each other, which would strongly suggest an association between the dense gas and the maser emission. Moreover, we find the bolometric luminosity of the embedded source and the isotropic luminosity of the H2O maser are also correlated. We conclude from the correlations of the cloud and water maser velocities and the bolometric and maser luminosity that there is a strong dynamical relationship between the embedded young massive star and the H2O maser.Comment: 17 pages and 17 figures and 8 tables. Tables\,2 and 5 and full versions of Figs. 3 and 7 are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.125.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A

    Turning back the tide of American mink invasion at unprecedented scales in partnership with communities

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    Lambin, X., Atkinson, S., Bryce, R., Davies, L., Gray, H., Oliver, M.K, Urquhart, J

    Women’s views about breast cancer prevention at mammography screening units and well women’s clinics

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    Background Women attending mammography screening units (msus) and well women’s clinics (wwcs) represent a motivated cohort likely to engage in interventions aimed at primary breast cancer (bca) prevention. Methods We used a feasibility questionnaire distributed to women (40–49 or 50–74 years of age) attending msus and wwcs in Halifax, Nova Scotia, to examine ■ women’s views about bca primary prevention and sources of health care information, ■ prevalence of lifestyle-related bca risk factors, and ■ predictors of prior mammography encounters within provincial screening guidelines. Variables examined included personal profiling, comorbidities, prior mammography uptake, lifestyle behaviours, socioeconomic status, health information sources, and willingness to discuss or implement lifestyle modifications, or endocrine therapy, or both. A logistic regression analysis examined associations with prior mammography encounters. Results Of the 244 responses obtained during 1.5 months from women aged 40–49 years (n = 75) and 50–74 years (n = 169), 56% and 75% respectively sought or would prefer to receive health information from within, as opposed to outside, health care. Lifestyle-related bca risk factors were prevalent, and most women were willing to discuss or implement lifestyle modifications (93%) or endocrine therapy (67%). Of the two age groups, 49% and 93% respectively had previously undergone mammography within guidelines. Increasing age and marital status (single, separated, or divorced vs. married or partnered) were independent predictors of prior mammography encounters within guidelines for women 40–49 years of age; no independent predictors were observed in the older age group. Conclusions Women attending msus and wwcs seem to largely adhere to mammography guidelines and appear motivated to engage in bca primary prevention strategies, including lifestyle modifications and endocrine therapy. Women’s views as observed in this study provide a rationale for the potential incorporation of bca risk assessment within the “mammogram point of care” to engage motivated women in bca primary prevention strategies

    ATLASGAL-selected massive clumps in the inner Galaxy: VI. Kinetic temperature and spatial density measured with formaldehyde

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    We aim to directly determine the kinetic temperature and spatial density with formaldehyde for the ∌\sim100 brightest ATLASGAL-selected clumps at 870 ÎŒ\mum representing various evolutionary stages of high-mass star formation. Ten transitions (JJ = 3-2 and 4-3) of ortho- and para-H2_2CO near 211, 218, 225, and 291 GHz were observed with the APEX 12 m telescope. Using non-LTE models with RADEX, we derive the gas kinetic temperature and spatial density using the measured p-H2_2CO 321_{21}-220_{20}/303_{03}-202_{02}, 422_{22}-321_{21}/404_{04}-303_{03}, and 404_{04}-303_{03}/303_{03}-202_{02} ratios. The gas kinetic temperatures derived from the p-H2_2CO 321_{21}-220_{20}/303_{03}-202_{02} and 422_{22}-321_{21}/404_{04}-303_{03} line ratios are high, ranging from 43 to >>300 K with an unweighted average of 91 ±\pm 4 K. Deduced TkinT_{\rm kin} values from the JJ = 3-2 and 4-3 transitions are similar. Spatial densities of the gas derived from the p-H2_2CO 404_{04}-303_{03}/303_{03}-202_{02} line ratios yield 0.6-8.3 ×\times 106^6 cm−3^{-3} with an unweighted average of 1.5 (±\pm0.1) ×\times 106^6 cm−3^{-3}. A comparison of kinetic temperatures derived from p-H2_2CO, NH3_3, and the dust emission indicates that p-H2_2CO traces a distinctly higher temperature than the NH3_3 (2,2)/(1,1) transitions and the dust, tracing heated gas more directly associated with the star formation process. The H2_2CO linewidths are found to be correlated with bolometric luminosity and increase with the evolutionary stage of the clumps, which suggests that higher luminosities tend to be associated with a more turbulent molecular medium. It seems that the spatial densities measured with H2_2CO do not vary significantly with the evolutionary stage of the clumps. However, averaged gas kinetic temperatures derived from H2_2CO increase with time through the evolution of the clumps.Comment: Accepted for publication in A&

    NALCN Dysfunction as a Cause of Disordered Respiratory Rhythm With Central Apnea

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    The sodium leak channel nonselective protein (NALCN) is a regulator of the pacemaker neurons that are responsible for rhythmic behavior (including respiration), maintaining the resting membrane potential, and are required for action potential production. NALCN-null mice show early death associated with disrupted respiratory rhythms, characterized by frequent and profound apneas. We report 3 children (2 siblings) with compound heterozygous mutations in NALCN associated with developmental impairment, hypotonia, and central sleep-disordered breathing causing apneas. Supplemental oxygen normalized the respiratory rhythm. NALCN mutations have been previously reported to cause severe hypotonia, speech impairment, and cognitive delay as well as infantile neuroaxonal dystrophy and facial dysmorphism. Nonsynonymous changes in the 2 affected extracellular loops may be responsible for the deleterious effect on the stability of the respiratory rhythm. Although oxygen is known to be a stabilizer of respiratory rhythm in central apnea in children, its role in NALCN dysfunction requires further investigation.</jats:p

    Variability in concentrations of potentially toxic elements in urban parks from six European cities

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    Use of a harmonised sampling regime has allowed comparison of concentrations of copper, chromium, nickel, lead and zinc in six urban parks located in different European cities differing markedly in their climate and industrial history. Wide concentrations ranges were found for copper, lead and zinc at most sites, but for chromium and nickel a wide range was only seen in the Italian park, where levels were also considerably greater than in other soils. As might be expected, the soils from older cities with a legacy of heavy manufacturing industry (Glasgow, Torino) were richest in potentially toxic elements (PTEs); soils from Ljubljana, Sevilla and Uppsala had intermediate metal contents, and soils from the most recently established park, in the least industrialised city (Aveiro), displayed lowest concentrations. When principal component analysis was applied to the data, associations were revealed between pH and organic carbon content; and between all five PTEs. When pH and organic carbon content were excluded from the PCA, a distinction became clear between copper, lead and zinc (the "urban" metals) on the one hand, and chromium and nickel on the other. Similar results were obtained for the surface (0-10 cm depth) and sub-surface (10-20 cm depth) samples. Comparisons with target or limit concentrations were limited by the existence of different legislation in different countries and the fact that few guidelines deal specifically with public-access urban soils intended for recreational use

    A Computation of the Maximal Order Type of the Term Ordering on Finite Multisets

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    We give a sharpening of a recent result of Aschenbrenner and Pong about the maximal order type of the term ordering on the finite multisets over a wpo. Moreover we discuss an approach to compute maximal order types of well-partial orders which are related to tree embeddings
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