1,294 research outputs found

    Mechanical properties of β-HMX

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    Background: For a full understanding of the mechanical properties of a material, it is essential to understand the defect structures and associated properties and microhardness indentation is a technique that can aid this understanding. Results: The Vickers hardness on (010), {011} and {110} faces lay in the range of 304-363 MPa. The Knoop Hardnesses on the same faces lay in the range 314-482 MPa. From etching of three indented surfaces, the preferred slip planes have been identified as (001) and (101). For a dislocation glide, the most likely configuration for dislocation movement on the (001) planes is (001) [100] (|b| = 0.65 nm) and for the (101) plane as (101) 101~(|b| = 1.084 nm) although (101) [010] (|b| = 1.105 nm) is possible. Tensile testing showed that at a stress value of 2.3 MPa primary twinning occurred and grew with increasing stress. When the stress was relaxed, the twins decreased in size, but did not disappear. The twinning shear strain was calculated to be 0.353 for the (101) twin plane. Conclusions: HMX is considered to be brittle, compared to other secondary explosives. Comparing HMX with a range of organic solids, the values for hardness numbers are similar to those of other brittle systems. Under the conditions developed beneath a pyramidal indenter, dislocation slip plays a major part in accommodating the local deformation stresses. © 2015 Gallagher et al.; licensee Springer

    Would you be surprised if this patient died?: Preliminary exploration of first and second year residents' approach to care decisions in critically ill patients

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    BACKGROUND: How physicians approach decision-making when caring for critically ill patients is poorly understood. This study aims to explore how residents think about prognosis and approach care decisions when caring for seriously ill, hospitalized patients. METHODS: Qualitative study where we conducted structured discussions with first and second year internal medicine residents (n = 8) caring for critically ill patients during Medical Intensive Care Unit Ethics and Discharge Planning Rounds. Residents were asked to respond to questions beginning with "Would you be surprised if this patient died?" RESULTS: An equal number of residents responded that they would (n = 4) or would not (n = 4) be surprised if their patient died. Reasons for being surprised included the rapid onset of an acute illness, reversible disease, improving clinical course and the patient's prior survival under similar circumstances. Residents reported no surprise with worsening clinical course. Based on the realization that their patient might die, residents cited potential changes in management that included clarifying treatment goals, improving communication with families, spending more time with patients and ordering fewer laboratory tests. Perceived or implied barriers to changes in management included limited time, competing clinical priorities, "not knowing" a patient, limited knowledge and experience, presence of diagnostic or prognostic uncertainty and unclear treatment goals. CONCLUSIONS: These junior-level residents appear to rely on clinical course, among other factors, when assessing prognosis and the possibility for death in severely ill patients. Further investigation is needed to understand how these factors impact decision-making and whether perceived barriers to changes in patient management influence approaches to care

    Dieting practices, weight perceptions, and body composition: A comparison of normal weight, overweight, and obese college females

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    BACKGROUND: Of concern to health educators is the suggestion that college females practice diet and health behaviors that contradict the 2005 dietary guidelines for Americans. In this regard, there remain gaps in the research related to dieting among college females. Namely, do normal weight individuals diet differently from those who are overweight or obese, and are there dieting practices used by females that can be adapted to promote a healthy body weight? Since it is well recognized that females diet, this study seeks to determine the dieting practices used among normal, overweight, and obese college females (do they diet differently) and identify dieting practices that could be pursued to help these females more appropriately achieve and maintain a healthy body weight. METHODS: A total of 185 female college students aged 18 to 24 years participated in this study. Height, weight, waist and hip circumferences, and skinfold thickness were measured to assess body composition. Surveys included a dieting practices questionnaire and a 30-day physical activity recall. Participants were classified according to body mass index (BMI) as normal weight (n = 113), overweight (n = 35), or obese (n = 21). Data were analyzed using JMP IN® software. Descriptive statistics included means, standard deviations, and frequency. Subsequent data analysis involved Pearson X(2 )and one-way analysis of variance with comparison for all pairs that were significantly different using Tukey-Kramer honestly significant difference test. RESULTS: Outcomes of this study indicate the majority of participants (83%) used dieting for weight loss and believed they would be 2% to 6% greater than current weight if they did not diet; normal weight, overweight, and obese groups perceived attractive weight to be 94%, 85%, and 74%, respectively, of current weight; 80% of participants reported using physical activity to control weight, although only 19% exercised at a level that would promote weight loss; only two of 15 dieting behaviors assessed differed in terms of prevalence of use among groups, which were consciously eating less than you want (44% normal weight, 57% overweight, 81% obese) and using artificial sweeteners (31% normal weight and overweight, 5% obese); and the most prevalent explicit maladaptive weight loss behavior was smoking cigarettes (used by 9% of participants) and most unhealthy was skipping breakfast (32%). CONCLUSION: Collectively, results indicate female college students, regardless of weight status, would benefit from open discussions with health educators regarding healthy and effective dieting practices to achieve/maintain a healthy body weight. The results are subject to replication among high school, middle-aged, and older females

    Inequality in treatment use among elderly patients with acute myocardial infarction: USA, Belgium and Quebec

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    <p>Abstract</p> <p>Background</p> <p>Previous research has provided evidence that socioeconomic status has an impact on invasive treatments use after acute myocardial infarction. In this paper, we compare the socioeconomic inequality in the use of high-technology diagnosis and treatment after acute myocardial infarction between the US, Quebec and Belgium paying special attention to financial incentives and regulations as explanatory factors.</p> <p>Methods</p> <p>We examined hospital-discharge abstracts for all patients older than 65 who were admitted to hospitals during the 1993–1998 period in the US, Quebec and Belgium with a primary diagnosis of acute myocardial infarction. Patients' income data were imputed from the median incomes of their residential area. For each country, we compared the risk-adjusted probability of undergoing each procedure between socioeconomic categories measured by the patient's area median income.</p> <p>Results</p> <p>Our findings indicate that income-related inequality exists in the use of high-technology treatment and diagnosis techniques that is not justified by differences in patients' health characteristics. Those inequalities are largely explained, in the US and Quebec, by inequalities in distances to hospitals with on-site cardiac facilities. However, in both Belgium and the US, inequalities persist among patients admitted to hospitals with on-site cardiac facilities, rejecting the hospital location effect as the single explanation for inequalities. Meanwhile, inequality levels diverge across countries (higher in the US and in Belgium, extremely low in Quebec).</p> <p>Conclusion</p> <p>The findings support the hypothesis that income-related inequality in treatment for AMI exists and is likely to be affected by a country's system of health care.</p

    A randomised controlled trial among cleaners-Effects on strength, balance and kinesiophobia

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    <p>Abstract</p> <p>Background</p> <p>Cleaners constitute a job group with poor health and low socioeconomic resources. Therefore, there is a great need for scientifically documented health promoting initiatives for cleaners. However, both workplace initiatives and high quality intervention studies are lacking. The aim of this study was to evaluate the effects of a 3-month workplace trial with interventions to improve physical or cognitive behavioural resources among cleaners.</p> <p>Methods</p> <p>A cluster randomised controlled trial was conducted among 294 female cleaners from 9 workplaces. The participants were allocated to three groups: Physical coordination training (PCT, n = 95), Cognitive behavioural theory-based training (CBTr, n = 99) and Reference group (REF, n = 100). Interventions were conducted during work hours for an average of 1 hour/week. Muscle strength was measured by maximal voluntary contractions in trunk/extension, and shoulder abduction/elevation. Postural balance was measured on a force platform. Kinesiophobia was measured with Tampa Scale for Kinesiophobia. Test and questionnaires were completed at baseline and at 3-month follow-up and analyses followed the intention-to-treat (ITT) principle with last observation carried forward in case of missing data at follow-up. Reports and analyses are given on true observations as well.</p> <p>Results</p> <p>ITT-analyses revealed that PCT improved strength of the trunk (p < .05) and postural balance (p < .05) compared to CBTr and REF. Based on true observations the strength and balance improvements corresponded to ~20% and ~16%, respectively. ITT-analyses showed that CBTr reduced kinesiophobia compared to PCT and REF (p < .05). Based on true observations, the improvement corresponded to a ~16% improvement.</p> <p>Conclusion</p> <p>This workplace-based intervention study including PCT and CBTr among cleaners improved strength and postural balance from PCT, and kinesiophobia from CBTr. The improved strength, postural balance and kinesiophobia may improve the cleaners' tolerance for high physical work demands. Future studies should investigate the potential in the combination of PCT and CBTr in a workplace intervention.</p> <p>Trial registration</p> <p>Current controlled trials <a href="http://www.controlled-trials.com/ISRCTN96241850">ISRCTN96241850</a></p

    Search for the glueball candidates f0(1500) and fJ(1710) in gamma gamma collisions

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    Data taken with the ALEPH detector at LEP1 have been used to search for gamma gamma production of the glueball candidates f0(1500) and fJ(1710) via their decay to pi+pi-. No signal is observed and upper limits to the product of gamma gamma width and pi+pi- branching ratio of the f0(1500) and the fJ(1710) have been measured to be Gamma_(gamma gamma -> f0(1500)). BR(f0(1500)->pi+pi-) < 0.31 keV and Gamma_(gamma gamma -> fJ(1710)). BR(fJ(1710)->pi+pi-) < 0.55 keV at 95% confidence level.Comment: 10 pages, 3 figure
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