502 research outputs found

    The partial molar volume of carbon dioxide in peridotite partial melt at high pressure

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    The partial molar volume of CO2 (VCO2) in silicate melt was determined for a komatiite composition using high pressure sink/float experiments in a multi-anvil press. The density of the experimental melt at pressure was determined by observing sinking and floating of pure forsterite (Fo100) and 90% forsterite (Fo90) buoyancy markers. Values for VCO2 were bracketed at 4.3 GPa (23.71 cm3/mol) and at 5.5 GPa (22.06 cm3/mol), normalized to 1850°C. Combining the current data with previous work we now more accurately constrain the compression curve of VCO2 over the pressure range of 1 bar to 20 GPa. These data allow the calculation of density at pressure of carbonated silicate melts, such as kimberlite and silica undersaturated alkali basalts, and the determination of their buoyancy and eruptibility

    Formal Mentoring Programs: An Exploration of Barriers to Implementation in Nursing Schools

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    Abstract Although there are over three million registered nurses in the United States, the national nursing shortage has reached epic proportions, with a vacancy rate of 9.9%. One of the contributing factors to the nursing shortage is the lack of qualified nursing faculty. While formal mentoring programs have been identified as best practice in supporting the expert nurse clinician in their transition into the novice nurse faculty role, these programs are not consistently implemented in schools of nursing. In this phenomenological study, the perceptions of nursing leaders regarding barriers to the implementation of formal mentoring programs were analyzed. Using a semistructured interview, six nursing school leaders were interviewed focusing on their perceptions of formal mentoring programs for novice nursing faculty. Findings of this study showed that nursing school leaders believe that mentoring programs are effective in supporting the novice nurse faculty in their role transition. Nursing leaders did, however, identify the barriers of human capacity, incentivization, and budgetary constraints to the implementation of formal mentoring programs. These barriers often outweighed the positive effects of formal mentoring programs. Nursing schools can enter academic partnerships with hospitals or secure grant funding to help support the implementation of formal mentoring programs. Additionally, working with novice mentors on how to teach someone to teach will be invaluable to the mentor dyad. Keywords: nurse, novice nurse academic, nurse educator, mentoring, orientation, transition, retentio

    Doctor of Philosophy

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    dissertationThe focus of this dissertation is threefold: conduct a systematic review to identify literature regarding the use of malaria control methods, identify rates of control method use, and identify predictors associated with the combined use of control methods among African children under age five through Demographic and Health Surveys (DHS). A systematic review identified literature regarding malaria control methods utilizing DHS surveys. Sixtyfive articles met the review criteria and were evaluated for insecticide treated nets (ITN) use, indoor residual spray (IRS), and prompt/appropriate treatment. While DHS datasets are a rich source to identify malaria practices in African children, additional research considering the combined use of malaria control methods is needed. DHS surveys from three countries at two separate time points were then analyzed to identify rates of children under five who reported fever and utilized one or more malaria control methods (ITNs, IRS, and/or prompt/appropriate treatment). Independent use of ITNs ranged from 30% to 75%, IRS from 1% to 18%, and prompt/appropriate treatment from 3% to 25%. Combined use of all control methods ranged between <1% to 3%. Within this descriptive analysis, while some improvements to using control methods were noted over time, independent and combined use of these methods are inadequate. Within the predictor analysis, using univariate, multivariate, and multinomial regression analysis, variables such as child age, maternal education, wealth index, and residence location were evaluated as possible predictors of the independent or combined use of these control methods. Higher maternal education and iv wealth were found to be significant predictors of using one malaria control method among some of the populations. The sample sizes for using two and three methods were extremely small and significant associations among the variables were few and sporadic. In summary, there were no predictors that remained consistent across all surveys. This final analysis demonstrates the necessity for further evaluation of availability, access, and effective dissemination of these control methods both singularly and in combination to improve the transmission and impact of malaria in these endemic populations

    The Frequency of Feedback when Affectivity is Involved

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    In this study, the role of feedback frequency and negative affectivity relating to self-efficacy, job satisfaction, and job performance was examined. In total, 148 participant responses were collected via internet survey. Using regression analysis, no support was found for feedback frequency predicting self-efficacy, job satisfaction, or perceptions of job performance. Support was found for affectivity negatively predicting self-efficacy, job satisfaction, and perceptions of job performance. These findings are consistent with previous affectivity research. An exploratory regression analysis was conducted to test if an interaction term composed of negative affectivity and feedback frequency predicted the dependent measures, but these analyses were not significant. Limitations of the current study and implications for future research are discussed

    Modeling Common Cause Failures of Thrusters on ISS Visiting Vehicles

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    This paper discusses the methodology used to model common cause failures of thrusters on the International Space Station (ISS) Visiting Vehicles. The ISS Visiting Vehicles each have as many as 32 thrusters, whose redundancy and similar design make them susceptible to common cause failures. The Global Alpha Model (as described in NUREG/CR-5485) can be used to represent the system common cause contribution, but NUREG/CR-5496 supplies global alpha parameters for groups only up to size six. Because of the large number of redundant thrusters on each vehicle, regression is used to determine parameter values for groups of size larger than six. An additional challenge is that Visiting Vehicle thruster failures must occur in specific combinations in order to fail the propulsion system; not all failure groups of a certain size are critical

    Technologies, Ethics and Journalism’s Relationship with the Public

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    Drones can provide a bird’s eye view of breaking news and events that can be streamed live or used in edited news coverage. Past research has focused on the training and ethics of journalists and drone operators. Little attention, however, has been given to audiences and their acceptance and perception of ethics. We suggest that audiences who are open to personal technology use will perceive news media using unmanned aerial vehicles (UAVs) as more ethical in an extension of the Diffusion of Innovation Theory. In a survey (N = 548) of adults living in the United States, we explore the correlates between trust, technology, privacy, and the use of UAVs. Results suggest all three are positively correlated with openness toward drone journalism. We find the audience has preferences for the types of news stories that should be covered using drones. Participants indicated they welcome drone journalism when covering traffic and investigative stories, but not celebrities and politicians. The findings have implications for newsrooms, suggesting transparency and outreach to educate people on the technology could help build trust. Further, the results suggest that Diffusion of Innovation theory can be applied when mediated through news media

    Generation and Genetic Characterization of Avian Reovirus Temperature-Sensitive Mutants

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    AbstractThere currently is little known about the genetic and biological functions of avian reovirus (ARV), an atypical member of the family Reoviridae and the prototype of all nonenveloped viruses that induce syncytia formation. In this study, we created ARV temperature-sensitive (ts) mutants by chemical mutagenesis of ARV strain 138. We developed a novel efficiency of lysis (EOL) screening technique and used it and the classical efficiency of plating (EOP) assay to identify 17 ARV ts mutants. Pairwise mixed infections of these mutants and evaluation of recombinant progeny ts status led to their organization into seven recombination groups. This indicates that these new groups of mutants represent the majority of the ARV genome. To phenotypically characterize the ts mutants, progeny double-stranded RNA (dsRNA) produced at permissive and nonpermissive temperature was measured. Some mutants were capable of dsRNA synthesis at the restrictive temperature (RNA+), which indicates the effects of their ts lesions occur after RNA replication. Most mutants were RNA−, which suggests their mutations affect stages in viral replication that precede progeny genome synthesis

    International Space Station Spacecraft Charging Hazards: Hazard Identification, Management, and Control Methodologies, with Possible Applications to Human Spaceflight Beyond LEO

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    In this paper, we present an overview of how the International Space Station (ISS) safety engineering methodology directed to controlling extravehicular activity (EVA) crew electrical shock hazards, caused by ISS spacecraft charging, has evolved over the past 25+ years. Long-term measurements of ISS charging severity and frequency-of-occurrence, combined with detailed probabilistic analysis of EVA electric shock- circuit completion, led to a change in hazard control methodology. The requirement for two-fault tolerant EVA shock hazard control during all EVAs was replaced with a less operationally burdensome and risky EVA shock hazard detection and warning process. The applicability of event probability-based detection-and- warning processes to human spaceflight charging hazard control beyond low-earth orbit (LEO) is also considered
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