Analysis of Hydrogen Cyanide Hyperfine Spectral Components towards Star Forming Cores

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

Hours-of-Rest Regulations in the Canadian Shipping Industry

This paper discusses hours of rest for Canadian shipping employees on the basis of statutory regulations, the research literature, and consultations with representatives of the shipping industry during four workshops held in different parts of Canada. Topics include analyses of current regulations, operational practices and research on work and rest and on time of day and rest, and recommendations for change. The analyses found that current regulations do not distinguish between sleep and recreation during rest periods and fall to take into account time of day effects in relation to quality of sleep. The proposed changes in the regulations require the use of non-rotating 24-hour duty schedules providing for minimum rest periods and maximum work periods

The association between nurse staffing and quality of care in emergency departments: A systematic review

Background: The relationship between nurse staffing, skill-mix and quality of care has been well-established in medical and surgical settings, however, there is relatively limited evidence of this relationship in emergency departments. Those that have been published identified that lower nurse staffing levels in emergency departments are generally associated with worse outcomes with the conclusion that the evidence in emergency settings was, at best, weak. Methods: We searched thirteen electronic databases for potentially eligible papers published in English up to December 2023. Studies were included if they reported on patient outcomes associated with nurse staffing within emergency departments. Observational, cross-sectional, prospective, retrospective, interrupted time-series designs, difference-in-difference, randomised control trials or quasi-experimental studies and controlled before and after studies study designs were considered for inclusion. Team members independently screened titles and abstracts. Data was synthesised using a narrative approach. Results: We identified 16 papers for inclusion; the majority of the studies (n = 10/16) were observational. The evidence reviewed identified that poorer staffing levels within emergency departments are associated with increased patient wait times, a higher proportion of patients who leave without being seen and an increased length of stay. Lower levels of nurse staffing are also associated with an increase in time to medications and therapeutic interventions, and increased risk of cardiac arrest within the emergency department. Conclusion: Overall, there remains limited high-quality empirical evidence addressing the association between emergency department nurse staffing and patient outcomes. However, it is evident that lower levels of nurse staffing are associated with adverse events that can result in delays to the provision of care and serious outcomes for patients. There is a need for longitudinal studies coupled with research that considers the relationship with skill-mix, other staffing grades and patient outcomes as well as a wider range of geographical settings. Tweetable abstract: Lower levels of nurse staffing in emergency departments are associated with delays in patients receiving treatments and poor quality care including an increase in leaving without being seen, delay in accessing treatments and medications and cardiac arrest

Meeting Report of the Third Annual Tri-Service Microbiome Consortium Symposium

The Tri-Service Microbiome Consortium (TSMC) was founded to enhance collaboration, coordination, and communication of microbiome research among U.S. Department of Defense (DoD) organizations and to facilitate resource, material and information sharing among consortium members. The 2019 annual symposium was held 22–24 October 2019 at Wright-Patterson Air Force Base in Dayton, OH. Presentations and discussions centered on microbiome-related topics within five broad thematic areas: 1) human microbiomes; 2) transitioning products into Warfighter solutions; 3) environmental microbiomes; 4) engineering microbiomes; and 5) microbiome simulation and characterization. Collectively, the symposium provided an update on the scope of current DoD microbiome research efforts, highlighted innovative research being done in academia and industry that can be leveraged by the DoD, and fostered collaborative opportunities. This report summarizes the presentations and outcomes of the 3rd annual TSMC symposium

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

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/)

Probing The Chemistry And Dynamics Of Hot Molecular Cores Using Highly Excited Cyanopolyynic Transitions

A hyperfine line fitting program is presented, which decomposes an observed rotational transition into its individual hyperfine components. The fit is optimized by the use of the Levenberg-Marquardt algorithm (for non-linear fitting) or Caruana’s algorithm (linearization of the Gaussian function). From the optimal fit, various parameters from the decomposed components are derived such as the linewidth dispersion, peak brightness temperature and peak position in velocity units. The closeness in frequency units of two neighbouring hyperfine components within a rotational transition spectrum allows the derivation of a more credible estimate of the optical depth for the observed source of emission. Effective smoothing of the data subsequent to the fitting procedure greatly reduces the perceived error in the determination of various physical conditions of the observed region. The technique has been employed in observations of massive hot molecular cores (HMCs), considered to be the birthplace of high mass stars. In particular, observations of the cyanopolyynes HC$\rm_3$N and HC$\rm_5$N, each of which include a quadrupole hyperfine structure, as well as methyl cyanide, CH$\rm_3$CN, have been analysed with this technique and modelled with a radiative transfer code incorporating non-LTE conditions, in order to derive abundances and column densities for a total of 10 HMCs and 5 massive cores. Using these derived parameters for each core, we have been able to test the time-dependent chemical models presented for these species by Chapman et al. (2009) and thus verify the suitability of their usefulness as "chemical clocks" by which to constrain the ages of the observed objects. In addition to this work, a detailed study of the magnetic hyperfine structure of a selection of inversion transitions of NH$\rm_3$ is presented. As part of the continuing preparatory work for Herschel, SOFIA and, in particular, ALMA - improved rest frequencies for this commonly used kinetic temperature detecting species in star-forming cores will be forthcoming

Hierarchical gravitational fragmentation. I. Collapsing cores within collapsing clouds

The Hierarchical Gravitational Fragmentation scenario is investigated through numerical simulations of the prestellar stages of the collapse of a marginally gravitationally unstable isothermal sphere immersed in a strongly gravitationally unstable, uniform background medium. The core developes a Bonnor–Ebert (BE)-like density profile, while at the time of singularity (the protostar) formation the envelope approaches a singular-isothermal sphere (SIS)-like r^−2 density profile. However, these structures are never hydrostatic. In this case, the central flat region is characterized by an infall speed linear with radius, while the envelope is characterized by a uniform infall speed. This implies that the hydrostatic SIS initial condition leading to Shuʼs classical inside-out solution is not expected to occur, and therefore neither should the inside-out solution. Instead, the solution collapses from the outside-in, naturally explaining the observation of extended infall velocities. The core, defined by the radius at which it merges with the background, has time-variable mass and radius, and evolves along the locus of the ensemble of observed prestellar cores in a plot of Mcore/MBE versus Mcore, spanning the range from the “stable” to the “unstable” regimes, even though it is collapsing at all times. We conclude that the presence of an unstable background allows a core to evolve dynamically from the time when it first appears, even when it resembles a pressure-confined, stable BE-sphere. The core can be thought of as a ram-pressure confined BE-sphere, with an increasing mass due to the accretion from the unstable background