134 research outputs found

    Observation of HCN hyperfine line anomalies towards low- and high-mass star-forming cores

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    HCN is becoming a popular choice of molecule for studying star formation in both low- and high-mass regions and for other astrophysical sources from comets to high-redshift galaxies. However, a major and often overlooked difficulty with HCN is that it can exhibit non-local thermodynamic equilibrium (non-LTE) behaviour in its hyperfine line structure. Individual hyperfine lines can be strongly boosted or suppressed. In low-mass star-forming cloud observations, this could possibly lead to large errors in the calculation of opacity and excitation temperature, while in massive star-forming clouds, where the hyperfine lines are blended due to turbulent broadening, errors will arise in infall measurements that are based on the separation of the peaks in a self-absorbed profile. The underlying line shape cannot be known for certain if hyperfine anomalies are present. We present a first observational investigation of these anomalies across a range of conditions and transitions by carrying out a survey of low-mass starless cores (in Taurus & Ophiuchus) and high-mass protostellar objects (in the G333 giant molecular cloud) using hydrogen cyanide (HCN) J=1-0 and J=3-2 emission lines. We quantify the degree of anomaly in these two rotational levels by considering ratios of individual hyperfine lines compared to LTE values. We find that all the cores observed show some degree of anomaly while many of the lines are severely anomalous. We conclude that HCN hyperfine anomalies are common in both lines in both low-mass and high-mass protostellar objects, and we discuss the differing hypotheses for the generation of the anomalies. In light of the results, we favour a line overlap effect for the origins of the anomalies. We discuss the implications for the use of HCN as a dynamical tracer and suggest in particular that the J=1-0, F=0-1 hyperfine line should be avoided in quantitative calculations.Comment: 17 pages, 8 figure

    Analysis of Hydrogen Cyanide Hyperfine Spectral Components towards Star Forming Cores

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    Although hydrogen cyanide has become quite a common molecular tracing species for a variety of astrophysical sources, it, however, exhibits dramatic non-LTE behaviour in its hyperfine line structure. Individual hyperfine components can be strongly boosted or suppressed. If these so-called hyperfine line anomalies are present in the HCN rotational spectra towards low or high mass cores, this will affect the interpretation of various physical properties such as the line opacity and excitation temperature in the case of low mass objects and infall velocities in the case of their higher mass counterparts. This is as a consequence of the direct effects that anomalies have on the underlying line shape, be it with the line structural width or through the inferred line strength. This work involves the first observational investigation of these anomalies in two HCN rotational transitions, J=1!0 and J=3!2, towards both low mass starless cores and high mass protostellar objects. The degree of anomaly in these two rotational transitions is considered by computing the ratios of neighboring hyperfine lines in individual spectra. Results indicate some degree of anomaly is present in all cores considered in our survey, the most likely cause being line overlap effects among hyperfine components in higher rotational transitions.Comment: 8th Serbian Conference on Spectral Line Shapes in Astrophysics, Divicibare; 8 pages, 5 figure

    Development and evaluation of a molecular diagnostic method to rapidly detect Histoplasma capsulatum var. farciminosum, the causative agent of epizootic lymphangitis, in equine clinical samples.

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    Histoplasma capsulatum var. farciminosum (HCF), the causative agent of epizootic lymphangitis (EZL), is endemic in parts of Africa. Diagnosis based on clinical signs and microscopy lacks specificity, and is a barrier to further understanding this neglected disease. Here, a nested PCR method targeting the ITS region of the rRNA operon was validated for application to equine clinical samples. Twenty-nine horses with signs of EZL, from different climatic regions of Ethiopia, were clinically examined. Blood samples and aspirates of pus from cutaneous nodules were taken, along with blood from a further 20 horses with no cutaneous EZL lesions. HCF was confirmed in DNA extracts of pus and blood samples from 25 and 17 horses, respectively, of the 29 suspected EZL cases. Positive PCR results were also obtained from heat-inactivated pus (24 horses) and blood (23 horses) spotted onto Whatman FTA cards. Two positives were obtained among blood samples from 20 horses that did not exhibit clinical signs of EZL. These are the first reports of the direct detection of HCF in equine blood, and at high frequency amongst horses exhibiting cutaneous lesions. The nested PCR outperformed conventional microscopic diagnosis, as characteristic yeast cells could only be observed in 14 pus samples. HCF DNA was confirmed by sequencing the cloned PCR products, and while alignment of the ITS amplicons showed very little sequence variation, there was preliminary SNP-based evidence for the existence of two subgroups of HCF. This molecular diagnostic method now permits investigation of the epidemiology of EZL

    CDC Botswana : sharing another partnership success

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    CDC Botswana, in partnership with the Ministry of Health since 1995--for a safer, healthier Botswana.Publication date from document properties.CDCBotswanaSharesSuccess_19_07_12.pd

    An Airport Experience Framework from a Tourism Perspective

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    This study, by integrating the perspectives of sociological, psychological, and service marketing and management, all of which affect the passenger experience, proposes a theoretical framework for the creation of the airport experience in relation to tourism. This research responds to the current phenomenon in which airports are offering other types of experiences within the airport terminal, expanding the role of an airport from being a utility for transportation into a place where various and different values can be offered. This research explores the current airport experience and adds to research on airport experience by clarifying ten key components necessary for airport passenger experience propositions based on existing research, the current industry phenomena, and the empirical study. The paper also underlines those components that can enhance passenger experience in relation to tourism and highlights the role that airports contribute to a destination

    The Radio Ammonia Mid-plane Survey (RAMPS) Pilot Survey

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    The Radio Ammonia Mid-Plane Survey (RAMPS) is a molecular line survey that aims to map a portion of the Galactic midplane in the first quadrant of the Galaxy (l = 10°–40°, | b| \leqslant 0\buildrel{\circ}\over{.} 4) using the Green Bank Telescope. We present results from the pilot survey, which has mapped approximately 6.5 square degrees in fields centered at l = 10°, 23°, 24°, 28°, 29°, 30°, 31°, 38°, 45°, and 47°. RAMPS observes the NH3 inversion transitions NH3(1,1)–(5,5), the H2O 61,6–52,3 maser line at 22.235 GHz, and several other molecular lines. We present a representative portion of the data from the pilot survey, including NH3(1,1) and NH3(2,2) integrated intensity maps, H2O maser positions, maps of NH3 velocity, NH3 line width, total NH3 column density, and NH3 rotational temperature. These data and the data cubes from which they were produced are publicly available on the RAMPS website (http://sites.bu.edu/ramps/)

    The EEG signature of sensory evidence accumulation during decision formation closely tracks subjective perceptual experience

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    How neural representations of low-level visual information are accessed by higher-order processes to inform decisions and give rise to conscious experience is a longstanding question. Research on perceptual decision making has revealed a late event-related EEG potential (the Centro-Parietal Positivity, CPP) to be a correlate of the accumulation of sensory evidence. We tested how this evidence accumulation signal relates to externally presented (physical) and internally experienced (subjective) sensory evidence. Our results show that the known relationship between the physical strength of the external evidence and the evidence accumulation signal (reflected in the CPP amplitude) is mediated by the level of subjective experience of stimulus strength. This shows that the CPP closely tracks the subjective perceptual evidence, over and above the physically presented evidence. We conclude that a remarkably close relationship exists between the evidence accumulation process (i.e. CPP) and subjective perceptual experience, suggesting that neural decision processes and components of conscious experience are tightly linked

    Hypothermia following antipsychotic drug use

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    Objective: Hypothermia is an adverse drug reaction (ADR) of antipsychotic drug (APD) use. Risk factors for hypothermia in ADP users are unknown. We studied which risk factors for hypothermia can be identified based on case reports. Method: Case reports of hypothermia in APD-users found in PUBMED or EMBASE were searched for risk factors. The WHO international database for Adverse Drug Reactions was searched for reports of hypothermia and APD use. Results: The literature search resulted in 32 articles containing 43 case reports. In the WHO database, 480 reports were registered of patients developing hypothermia during the use of APDs which almost equals the number of reports for hyperthermia associated with APD use (n=524). Hypothermia risk seems to be increased in the first days following start or dose increase of APs. APs with strong 5-HT2 antagonism seem to be more involved in hypothermia; 55% of hypothermia reports are for atypical antipsychotics. Schizophrenia was the most prevalent diagnosis in the case reports. Conclusion: Especially in admitted patients who are not able to control their own environment or physical status, frequent measurements of body temperature (with a thermometer that can measure low body temperatures) must be performed in order to detect developing hypothermia
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