Trauma Resulting in Respiratory Failure

Respiratory failure may occur secondary to thoracic trauma. Several important conditions develop as a result of chest injuries and may occur singly, or in combination, in patients with injuries from any cause. Unrecognized and therefore without proper management, the results are necessarily poor. If recognized and their mode of production is understood, treatment may be simple

P17. P3b event-related potentials show changes in varsity football players due to accumulated sub-concussive head impacts

BACKGROUND: Concussion has been a focus in football at all levels of participation. However, there is a growing appreciation that repetitive sub-concussive impacts may have more significant effects on overall neurological health than the isolated diagnosed concussions that have been the focus of recent research. The purpose of this study was to evaluate the relationship between the number of head impacts that players experience throughout the season and their P300 evoked potential. METHODS: Canadian university football players (n=45) were separated into three groups based on player mass and position/skill (small-skilled, big-skilled and big-unskilled). Groups were separated into low and high levels of impact exposure based on the total number of head impacts experienced in-season. Players completed baseline, midseason, postseason, and follow-up neurophysiological tests to measure P300 evoked potentials. Statistically significant differences between high versus low impact subgroups for each player group were assessed using independent-samples t-tests. RESULTS: Small-skilled and big-skilled players showed statistically significant decreases in P300 amplitude at midseason and postseason for high impact players compared to low impact players. Follow-up measures revealed that all groups were not significantly different compared to baseline measures. DISCUSSION & CONCLUSION: Players that experience a large number of head impacts in varsity football demonstrate significant decreases in specific EEG measures of cognitive function and information processing. INTERDISCIPLINARY REFLECTION: The combination of biomechanical head impact exposure with neurophysiological outcomes yields insight into the processes behind head impacts and their effects on the human brain

The Dual Origin of Stellar Halos II: Chemical Abundances as Tracers of Formation History

Fully cosmological, high resolution N-Body + SPH simulations are used to investigate the chemical abundance trends of stars in simulated stellar halos as a function of their origin. These simulations employ a physically motivated supernova feedback recipe, as well as metal enrichment, metal cooling and metal diffusion. As presented in an earlier paper, the simulated galaxies in this study are surrounded by stellar halos whose inner regions contain both stars accreted from satellite galaxies and stars formed in situ in the central regions of the main galaxies and later displaced by mergers into their inner halos. The abundance patterns ([Fe/H] and [O/Fe]) of halo stars located within 10 kpc of a solar-like observer are analyzed. We find that for galaxies which have not experienced a recent major merger, in situ stars at the high [Fe/H] end of the metallicity distribution function are more [alpha/Fe]-rich than accreted stars at similar [Fe/H]. This dichotomy in the [O/Fe] of halo stars at a given [Fe/H] results from the different potential wells within which in situ and accreted halo stars form. These results qualitatively match recent observations of local Milky Way halo stars. It may thus be possible for observers to uncover the relative contribution of different physical processes to the formation of stellar halos by observing such trends in the halo populations of the Milky Way, and other local L* galaxies.Comment: Version accepted for publication in ApJ Part 1. This version of the paper has been extended to include a detailed discussion of numerical issue

Pathogenesis of Murine Gammaherpesvirus-68 Infection in Interleukin-6-Deficient Mice

AbstractMurine gammaherpesvirus-68 (MHV-68) induces high levels of interleukin (IL)-6 production in both naive and primed lymphocyte populations. Mice that are homozygous (−/−) for deletion of the IL-6 gene were used to investigate the role of this cytokine in MHV-68 infection. The results showed that IL-6 is not essential for clearance of infectious MHV-68 from the lung or for the establishment, or control, of viral latency. Both IL-6 +/+ and −/− mice eliminated replicating virus from the respiratory tract within 15 days of infection, and their lungs remained clear of infectious virus for ≥150 days. Interestingly, the IL-6 −/− mice had both increased numbers of natural killer (NK)1.1+ cells and higher levels of NK cell activity than the +/+ controls at 10–15 days after infection. However, there was no difference in the cytotoxic T cell activity between the two groups of mice. Levels of latent virus were comparable in IL-6 +/+ and −/− mice over the time course studied. Furthermore, analysis of the numbers, types, and activation status of the various leukocyte subsets (other than NK cells) in the bronchoalveolar lavage population, lymph nodes, and spleens of +/+ and −/− mice revealed no striking differences. Apart from the expected lack of IL-6, cytokine profiles were not dramatically altered in IL-6 −/− mice. Thus, there is no evidence for an obligatory role for IL-6 in T cell activation during infection with MHV-68

The effects of job embeddedness on organizational citizenship, job performance, volitional absences, and voluntary turnover

This study extends theory and research on job embeddedness, which was disaggregated into its two major subdimensions, on-the-job and off-the-job embeddedness. As hypothesized, regression analyses revealed that off-the-job embeddedness was significantly predictive of subsequent voluntary turnover and volitional absences, whereas on-the-job embeddedness was not. Also as hypothesized, on-the-job embeddedness was significantly predictive of organizational citizenship and job performance, whereas off-the-job embeddedness was not. In addition, embeddedness moderated the effects of absences, citizenship, and performance on turnover. Implications are discussed

Faint dwarfs as a test of DM models: WDM vs. CDM

We use high resolution Hydro$+$N-Body cosmological simulations to compare the assembly and evolution of a small field dwarf (stellar mass ~ 10$^{6-7}$ M$\odot$, total mass 10$^{10}$ M$\odot$ in $\Lambda$ dominated CDM and 2keV WDM cosmologies. We find that star formation (SF) in the WDM model is reduced and delayed by 1-2 Gyr relative to the CDM model, independently of the details of SF and feedback. Independent of the DM model, but proportionally to the SF efficiency, gas outflows lower the central mass density through `dynamical heating', such that all realizations have circular velocities $<$ 20kms at 500$~$pc, in agreement with local kinematic constraints. As a result of dynamical heating, older stars are less centrally concentrated than younger stars, similar to stellar population gradients observed in nearby dwarf galaxies. Introducing an important diagnostic of SF and feedback models, we translate our simulations into artificial color-magnitude diagrams and star formation histories in order to directly compare to available observations. The simulated galaxies formed most of their stars in many $\sim$10 Myr long bursts. The CDM galaxy has a global SFH, HI abundance and Fe/H and alpha-elements distribution well matched to current observations of dwarf galaxies. These results highlight the importance of directly including `baryon physics' in simulations when 1) comparing predictions of galaxy formation models with the kinematics and number density of local dwarf galaxies and 2) differentiating between CDM and non-standard models with different DM or power spectra.Comment: 13 pages including Appendix on Color Magnitude Diagrams. Accepted by MNRAS. Added one plot and details on ChaNGa implementation. Reduced number of citations after editorial reques

A Novel Method for Remediation of PCBs in Weathered Coatings

Polychlorinated biphenyls (PCBs) are a group of synthetic aromatic compounds with the general formula C 12H1oCl that were historically used in industrial paints, caulking material and adhesives, as their properties enhanced structural integrity, reduced flammability and boosted antifungal properties. Although the United States Environmental Protection Agency (USEPA) has banned the manufacture of PCBs since 1979, they have been found in at least 500 of the 1,598 National Priorities List (Superfund) sites identified by the USEPA. Prior to the USEPA's ban on PCB production, PCBs were commonly used as additives in paints and asphalt-based adhesives that were subsequently applied to a variety of structures. Government facilities constructed as early as 1930 utilized PCB-containing binders or PCB-containing paints, which are now leaching into the environment and posing ecological and worker health concerns. To date, no definitive in situ, non-destructive method is available for the removal of PCBs found in weathered coatings or on painted structures/equipment. The research described in this paper involves the laboratory development and field-scale deployment of a new and innovative solution for the removal and destruction of PCBs found in painted structures or within the binding or caulking material on structures. The technology incorporates a Bimetallic Treatment System (BTS) that extracts and degrades only the PCBs found on the facilities, leaving the structure virtually unaltered