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Introduction: Simulation has assumed an integral role in the Canadian healthcare system with applications in quality improvement, systems development, and medical education. High quality simulation-based research (SBR) is required to ensure the effective and efficient use of this tool. This study sought to establish national SBR priorities and describe the barriers and facilitators of SBR in Emergency Medicine (EM) in Canada. Methods: Simulation leads (SLs) from all fourteen Canadian Departments or Divisions of EM associated with an adult FRCP-EM training program were invited to participate in three surveys and a final consensus meeting. The first survey documented active EM SBR projects. Rounds two and three established and ranked priorities for SBR and identified the perceived barriers and facilitators to SBR at each site. Surveys were completed by SLs at each participating institution, and priority research themes were reviewed by senior faculty for broad input and review. Results: Twenty SLs representing all 14 invited institutions participated in all three rounds of the study. 60 active SBR projects were identified, an average of 4.3 per institution (range 0-17). 49 priorities for SBR in Canada were defined and summarized into seven priority research themes. An additional theme was identified by the senior reviewing faculty. 41 barriers and 34 facilitators of SBR were identified and grouped by theme. Fourteen SLs representing 12 institutions attended the consensus meeting and vetted the final list of eight priority research themes for SBR in Canada: simulation in CBME, simulation for interdisciplinary and inter-professional learning, simulation for summative assessment, simulation for continuing professional development, national curricular development, best practices in simulation-based education, simulation-based education outcomes, and simulation as an investigative methodology. Conclusion: Conclusion: This study has summarized the current SBR activity in EM in Canada, as well as its perceived barriers and facilitators. We also provide a consensus on priority research themes in SBR in EM from the perspective of Canadian simulation leaders. This group of SLs has formed a national simulation-based research group which aims to address these identified priorities with multicenter collaborative studies.
Accurate models of X-ray absorption and re-emission in partly stripped ions are necessary to calculate the structure of stars, the performance of hohlraums for inertial confinement fusion and many other systems in high-energy-density plasma physics. Despite theoretical progress, a persistent discrepancy exists with recent experiments at the Sandia Z facility studying iron in conditions characteristic of the solar radiative–convective transition region. The increased iron opacity measured at Z could help resolve a longstanding issue with the standard solar model, but requires a radical departure for opacity theory. To replicate the Z measurements, an opacity experiment has been designed for the National Facility (NIF). The design uses established techniques scaled to NIF. A laser-heated hohlraum will produce X-ray-heated uniform iron plasmas in local thermodynamic equilibrium (LTE) at temperatures
eV and electron densities
. The iron will be probed using continuum X-rays emitted in a
diameter source from a 2 mm diameter polystyrene (CH) capsule implosion. In this design,
of the NIF beams deliver 500 kJ to the
mm diameter hohlraum, and the remaining
directly drive the CH capsule with 200 kJ. Calculations indicate this capsule backlighter should outshine the iron sample, delivering a point-projection transmission opacity measurement to a time-integrated X-ray spectrometer viewing down the hohlraum axis. Preliminary experiments to develop the backlighter and hohlraum are underway, informing simulated measurements to guide the final design.
Positive psychological constructs have been associated with reduced suicidal ideation, and interventions to cultivate positive feelings have the potential to reduce suicide risk. This study compares the efficacy of a 6-week, telephone-based positive psychology (PP) intervention against a cognition-focused (CF) control intervention among patients recently hospitalized for depression and suicidal ideation or behavior.
A total of 65 adults with a current major depressive episode reporting suicidal ideation or a recent suicide attempt were enrolled from participating in-patient psychiatric units. Prior to discharge, participants were randomized to the PP (n = 32) or CF (n = 33) intervention. In both interventions, participants received a treatment manual, performed weekly PP (e.g. gratitude letter) or CF (e.g. recalling daily events) exercises, and completed weekly one-on-one telephone sessions over 6 weeks. Between-group differences in hopelessness (primary outcome), depression, suicidality and positive psychological constructs at 6 and 12 weeks were tested using mixed-effects models accounting for intensity of post-hospitalization psychiatric treatment.
Compared with PP, the CF intervention was associated with significantly greater improvements in hopelessness at 6 weeks (β = −3.15, 95% confidence interval −6.18 to −0.12, effect size = −0.84, p = 0.04), but not 12 weeks. Similarly, the CF intervention led to greater improvements in depression, suicidal ideation, optimism and gratitude at 6 and 12 weeks.
Contrary to our hypothesis, the CF intervention was superior to PP in improving hopelessness, other suicide risk factors and positive psychological constructs during a key post-discharge period among suicidal patients with depression. Further study of this CF intervention is warranted in populations at high suicide risk.
An obesity paradox has been proposed in many conditions including HIV. Studies conducted to investigate obesity and its effect on HIV disease progression have been inconclusive and are lacking for African settings. This study investigated the relationship between overweight/obesity (BMI≥25 kg/m2) and HIV disease progression in HIV+ asymptomatic adults not on antiretroviral treatment (ART) in Botswana over 18 months. A cohort study in asymptomatic, ART-naïve, HIV+ adults included 217 participants, 139 with BMI of 18·0–24·9 kg/m2 and seventy-eight participants with BMI≥25 kg/m2. The primary outcome was time to event (≥25 % decrease in cluster of differentiation 4 (CD4) cell count) during 18 months of follow-up; secondary outcomes were time to event of CD4 cell count<250 cells/µl and AIDS-defining conditions. Proportional survival hazard models were used to compare hazard ratios (HR) on time to events of HIV disease progression over 18 months. Higher baseline BMI was associated with significantly lower risk of an AIDS-defining condition during the follow-up (HR 0·218; 95 % CI 0·068, 0·701; P=0·011). Higher fat mass at baseline was also significantly associated with decreased risk of AIDS-defining conditions during the follow-up (HR 0·855; 95 % CI 0·741, 0·987; P=0·033) and the combined outcome of having CD4 cell count≤250/µl and AIDS-defining conditions, whichever occurred earlier (HR 0·918; 95 % CI 0·847, 0·994; P=0·036). All models were adjusted for covariates. Higher BMI and fat mass among the HIV-infected, ART-naïve participants were associated with slower disease progression. Mechanistic research is needed to evaluate the association between BMI, fat mass and HIV disease progression.
The material properties of two ultra low-k organic polymers are characterized for copper interconnect integration. The k-values are 2.2-2.3 for both. Compared to OSG materials of similar k-values, these polymers have lower porosity and smaller pore size, achieved using selfassembled chemistry. Both materials demonstrate excellent resistance to plasma damage: no water uptake was detected after exposure to selected etching plasmas. This characteristic, combined with the small pore size and low porosity, results in the successful integration of the organic low-ks in 80 nm spacing with no significant increase in the integrated k-values.
It is found that higher open porosity in polymer A is accompanied by higher leakage current, which is not however linked to lower dielectric breakdown lifetimes.
We have demonstrated a uniform, robust interface for high-k deposition with significant improvements in device electrical performance compared to conventional surface preparation techniques. The interface was a thin thermal oxide that was grown and then etched back in a controlled manner to the desired thickness. Utilizing this approach, an equivalent oxide thickness (EOT) as low as 0.87 nm has been demonstrated on high-k gate stacks having improved electrical characteristics as compared to more conventionally prepared starting surfaces.
The challenges posed by long duration human space flight have made regenerable air revitalization a critical technology. Current systems using disposable lithium hydroxide do not address the difficulties presented by long duration missions. Solid amine systems offer the capability to regeneratively adsorb CO2 using an amine—impregnated porous substrate. Desorption of CO2 is then achieved by exposing the system to vacuum or by increasing temperature. However, thermal inefficiencies and system size constraints prevent adoption of regenerable systems on current and future space vehicles. A key challenge is the thermal management of the adsorbing bed. The adsorbing surface increases in temperature which reduces adsorbing efficiency. The removal of CO2 reduces temperature, which in turn produces a loss in regeneration efficiency. These thermal inefficiencies necessitate prohibitively large volumes of traditional solid-amine materials, which do not have optimized surface areas and pore distributions. Single-wall carbon nanotubes (SWCNTs) may provide a means to increase surface area of the amine support and thermal efficiency. Recent work by Cinke et. al. provided a method of functionalizing SWCNTs and increasing the surface area to the order of 1500 m2/g . We will report on the production of free standing, high surface area carbon nanotube structures currently being impregnated with amines. This novel SWCNT/amine approach will be compared with the current state of the art polymer structure-based system and characterized using SEM, TEM, surface area analysis through Brunauer-Emmett-Teller (BET), and also thermogravimetric equilibrium absorption. Results of SWCNT material improvements from processing modifications will also be presented.
AC Coupled Interconnection (ACCI), in conjunction with buried solder bump technology, provides a method to achieve signal I/O pitches of less than 75 μm and signaling rates greater than 5 Gbps per I/O on integrated circuits, while preserving excellent signal integrity. This paper presents a summary of approaches, status, and discusses material issues important to performance.
Tapirs (Tapiridae) are the last representatives of the Pleistocene megafauna of South and Central America. How they affect the ecology of plants was examined by studying the diversity, abundance, and condition of seeds defecated by the lowland tapir (Tapirus terrestris) in Amazonian Brazil. Additionally, the spatio-temporal pattern of the seed-rain and seed-shadows generated by tapirs was recorded. Three hundred and fifty-six tapir faeces were examined. Eleven per cent were found in water (n = 41), while 88% were located on dry land (n = 315). Of those found on dry land, 84% were located at sites that flood seasonally, while 14% of the total were encountered at forest sites that do not flood. In 127 faeces checked in the laboratory over 12 906 seeds of at least 39 species were found. Seed viability ranged from 65% for Maximiliana maripa to 98% for Enterolobium schomburgkii. Of nine seed species planted in the laboratory, seven germinated within 4 wk, with one species achieving an 89% germination rate. For many species recruitment to the seedling stage was also high under natural conditions, with 13 plant species occurring as seedlings in older faeces. Tapir generated seed-rain occurred throughout the year, with seeds defecated in all months. Two temporal patterns in species seed rain occurred: (1) contiguous monthly occurrence with peaks in abundance, and (2) discontinuous occurrence (time clumped) with small (a few months) to large (many months to more than a year) temporal gaps. The highest diversity of seeds appeared in April, at the end of the dry season. As the last of the Pleistocene megafauna of the region, tapirs may have particular importance as dispersers of large seeds and generators of unique seed dispersion patterns.
Recently there has been a paradigm shift in nonvolatile computer memories from silicon-technology-based EEPROMs (electrically erasable, programmable read-only memories) to devices in which the stored information is coded into + and − polarizations in thin-film ferroelectric capacitors. Such devices have read and erase/rewrite speeds of the order of 1–35 ns, many orders of magnitude faster than the erase/rewrite speeds of the best EEPROMs (Table I). However, fundamental questions concerning their lifetimes had delayed full commercialization. Because ferroelectrics normally have extremely large dielectric constants, their use as nonswitching capacitors in dynamic random-access memories (DRAMs) is also rapidly evolving. The majority of studies to date have emphasized lead zirconate titanate (PZT)-based capacitors for nonvolatile ferroelectric random-access memories (NVFRAMs) and barium strontium titanate-based capacitor DRAMs (see Table II).
The transmission electron microscope (TEM) is one of the most useful tools available to the materials scientist. Yet both the complexity and expense of the equipment, and the huge investment in time necessary to become proficient in specimen preparation and image acquisition and analysis, mean that it is difficult for most industrial institutions to maintain a state-of-the-art TEM facility. How can industry overcome this problem? One solution is to set up a collaboration with a university, an industrial partner, or a government research laboratory. Such collaborations can be extremely valuable to the company, which gains access to microscopes, specimen-preparation equipment and the expertise of professional microscopists, and to the research laboratory, which benefits from the industrial perspective and the private sector's proficiency in materials preparation and processing.
Such collaborations exist, and they can produce excellent results. In this article, we present three case studies in which successful collaboration has occurred between industry and one of the Department of Energy's scientific user facilities, the National Center for Electron Microscopy (NCEM-see sidebar). Our aim is not only to describe results that we hope will be of scientific interest but also to encourage industrial researchers to consider collaborations with institutes such as NCEM.
Small carbon grains are assumed to be the carrier of the prominent interstellar ultra violet absorption at 217 nm. To investigate this hypothesis, we produced small carbon particles by evaporating graphite in an inert quenching gas atmosphere, collected the grains on substrates, and measured their optical spectra. In the course of this work – which in the decisive final phase was carried out with the help of K. Fostiropoulos and L. D. Lamb – we showed that the smoke samples contained substantial quantities of C60. The fullerene C60 (with small admixtures of C70) was successfully separated from the sooty particles and, for the first time, characterized as a solid. We suggested the name ‘fullerite’ for this new form of crystalline carbon.
The production of laboratory analogues of interstellar grains was the initial aim of our research. In the autumn of 1982 while one of us (D.R.H.) was a Humboldt Fellow at the Max Planck Institute of Nuclear Physics in Heidelberg we decided to study the optical spectra of carbon grains. We felt challenged by the intense, strong interstellar ultra violet (uv) absorption at 217 nm which it had been proposed was due to graphitic grains (see, for example, Stecher 1969). The arguments in favour of such carriers are based primarily on calculations of the absorption of small, almost spherical, particles which exhibit the dielectric functions of graphite (for more recent literature see, for example, Draine 1988). There had already been very early experimental attempts to produce graphitic smoke particles by almost the same technique that we later applied to C60 production (see, for example, Day & Huffman 1973).
Nanocrystalline α–Fe, Fe3C, and Fe7C3, particles with narrow size distributions were produced by CO2 laser pyrolysis of vapor mixtures of Fe(CO)5 and C2H4. Details of the synthesis procedure are discussed. Mossbauer spectroscopy and x-ray diffraction were used to identify the structural phases and the former was used also to study the magnetism of the nanoparticles. All the nanoparticles were observed to be ferromagnetic in this size range. If excess C2H4 appears in the reactant gas mixture, several monolayers of pyrolytic carbon were observed to form on the particle surface, as deduced from transmission electron microscopy and Raman scattering studies. Results of thermo-gravimetric analysis/mass spectroscopy studies of this carbon coating indicate it is gasified in hydrogen at temperatures T ∼ 250 °C.
An ionized cluster beam (ICB) source was used to deposit Pd onto oxidized silicon substrates. The ICB source was operated in both the neutral mode (no ionization and no acceleration) and in the ICB mode with ionization and acceleration voltages at 3 kV and 6 k.V. Also, substrate temperatures were varied between 100°C and 400°C. The Pd film thicknesses were generally between 1, 200Å and 1, 800Å, with one film thickness about 500Å. The films were examined by transmission electron microscopy (TEM), transmission electron diffraction (TED), and x-ray diffraction (XRD). Grain size measurements by TEM and XRD showed that ionization and acceleration of Pd resulted in a slight increase in grain size compared to films deposited without ionization or acceleration at any substrate temperature. However, the grain size increased significantly as the substrate temperature rose. XRD showed that all ICB deposited Pd films have significant (111) texturing as determined by comparison to XRD data for Pd powder. For Pd films deposited at 400°C, almost all grains were oriented with the (111) planes parallel to the substrate surface. The electrical conductivity of all Pd films was comparable to that of bulk Pd.