242 research outputs found

    Filamentary Star Formation: Observing the Evolution toward Flattened Envelopes

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    Filamentary structures are ubiquitous from large-scale molecular clouds (few parsecs) to small-scale circumstellar envelopes around Class 0 sources (~1000 AU to ~0.1 pc). In particular, recent observations with the Herschel Space Observatory emphasize the importance of large-scale filaments (few parsecs) and star formation. The small-scale flattened envelopes around Class 0 sources are reminiscent of the large-scale filaments. We propose an observationally derived scenario for filamentary star formation that describes the evolution of filaments as part of the process for formation of cores and circumstellar envelopes. If such a scenario is correct, small-scale filamentary structures (0.1 pc in length) with higher densities embedded in starless cores should exist, although to date almost all the interferometers have failed to observe such structures. We perform synthetic observations of filaments at the prestellar stage by modeling the known Class 0 flattened envelope in L1157 using both the Combined Array for Research in Millimeter-wave Astronomy (CARMA) and the Atacama Large Millimeter/Submillimeter Array (ALMA). We show that with reasonable estimates for the column density through the flattened envelope, the CARMA D-array at 3mm wavelengths is not able to detect such filamentary structure, so previous studies would not have detected them. However, the substructures may be detected with CARMA D+E array at 3 mm and CARMA E array at 1 mm as a result of more appropriate resolution and sensitivity. ALMA is also capable of detecting the substructures and showing the structures in detail compared to the CARMA results with its unprecedented sensitivity. Such detection will confirm the new proposed paradigm of non-spherical star formation.Comment: 9 pages, 10 figures. Accepted by Ap

    Historical background to the South African horse mackerel fishery and its management

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    The commercial fishery for the South African horse mackerel Trachurus capensis began in 1950. Horse mackerel are exploited by four fleets: purse-seine, offshore demersal, inshore demersal, and midwater trawl. Characterisation of the catches by these sectors is complex. A brief summary will be given here, and will be described in more detail later

    Sleep Apnea Monitoring System

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    Something’s missing from my education: Using a cross sectional survey to examine the needs and interest of Canadian medical students relating to their roles as teachers and educators

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    Background: Current theory in medical education emphasizes engaging learners as educators while tailoring teaching to their learning needs. However, little is known about learners’ perceptions of their proposed roles as teachers and educators.Methods: Canadian medical students were invited to complete an English language online questionnaire structured to include: teaching experience, participation and/or awareness of teacher development at their school and awareness and/or interest in further training in medical education. The survey was developed by the Canadian Association for Medical Education (CAME) Membership Subcommittee, and distributed via the Canadian Federation of Medical Students (CFMS) email list and the CAME twitter account in March 2014.Results: Of the 169 undergraduate medical student respondents, 36% (n=61) reported a lack of prior teaching experience and 45% (n=73) were unsure if their school provided teaching instruction. Overall, 91% (n=150) indicated that they planned to incorporate teaching or medical education into their future careers.Conclusion: While the majority of medical student respondents are expecting or planning to teach, most report not having access to adequate training through medical school. Further effort is necessary to support medical students as teachers to prepare them for increased teaching responsibilities as residents and to expose them to potential careers in medical education.

    Hake Data: problems, solutions and GLM CPUE sensitivity to alternate scenarios

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    The checks carried out on the hake offshore trawl catch and effort data, which provide the basis to split the catches by species and to obtain GLM-standardised CPUE indices of abundance by species, have focused on two separate steps. The first was a re-extract of the data from the original files to check for possible errors in the earlier extracts (this applies to the subset of the data for which size composition information can be unambiguously extracted). The second step was to increase the proportion of the data utilised (and at the same time to check for possible selection biases in the existing sample) by assigning size composition to drags for which this information was not directly available, on the basis of the average for other vessels for which this was available for the area and time at which the fishing concerned took place. The first step revealed a problem with extractions over the last few years which at times for certain vessels had linked the accumulated catch for the day with only the effort for the last trawl of the day, rather than for all trawls that day combined

    Comparing the Costs and Acceptability of Three Fidelity Assessment Methods for Assertive Community Treatment

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    Successful implementation of evidence-based practices requires valid, yet practical fidelity monitoring. This study compared the costs and acceptability of three fidelity assessment methods: on-site, phone, and expert-scored self-report. Thirty-two randomly selected VA mental health intensive case management teams completed all fidelity assessments using a standardized scale and provided feedback on each. Personnel and travel costs across the three methods were compared for statistical differences. Both phone and expert-scored self-report methods demonstrated significantly lower costs than on-site assessments, even when excluding travel costs. However, participants preferred on-site assessments. Remote fidelity assessments hold promise in monitoring large scale program fidelity with limited resources

    The 2010 operational management procedure for the South African Merluccius paradoxus and M.?capensis resources

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    The algorithm for the 2010 Operational Management Procedure (OMP) to provide TAC recommendations for the South African Merluccius paradoxus and M. capensis resources is empirical. It combines an increase or decrease of the TAC in relation to a) the magnitude of recent trends in CPUE and survey abundance estimates for both species and b) the relative level of recent CPUE and survey abundance estimates compared to a target level. The basis for the associated computations is set out below, with the tuning parameters given in Table 1. Details of the computation procedures for the CPUE and catch data are provided in Appendix A, and for the survey estimates of Biomass in Appendix B
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