902 research outputs found

    Design of a split Hopkinson pressure bar with partial lateral confinement

    Get PDF
    This paper presents the design of a modified split Hopkinson pressure bar (SHPB) where partial lateral con- finement of the specimen is provided by the inertia of a fluid annulus contained in a long steel reservoir. In contrast to unconfined testing, or a constant cell pressure applied before axial loading, lateral restraint is permitted to develop throughout the axial loading: this enables the high-strain-rate shear behaviour of soils to be characterised under conditions which are more representative of buried explosive events. A pressure transducer located in the wall of the reservoir allows lateral stresses to be quantified, and a dispersion-correction technique is used to provide accurate measurements of axial stress and strain. Preliminary numerical modelling is utilised to inform the experimental design, and the capability of the apparatus is demonstrated with specimen results for a dry quartz sand

    Individual-level socioeconomic status is associated with worse asthma morbidity in patients with asthma

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Low socioeconomic status (SES) has been linked to higher morbidity in patients with chronic diseases, but may be particularly relevant to asthma, as asthmatics of lower SES may have higher exposures to indoor (e.g., cockroaches, tobacco smoke) and outdoor (e.g., urban pollution) allergens, thus increasing risk for exacerbations.</p> <p>Methods</p> <p>This study assessed associations between adult SES (measured according to educational level) and asthma morbidity, including asthma control; asthma-related emergency health service use; asthma self-efficacy, and asthma-related quality of life, in a Canadian cohort of 781 adult asthmatics. All patients underwent a sociodemographic and medical history interview and pulmonary function testing on the day of their asthma clinic visit, and completed a battery of questionnaires (Asthma Control Questionnaire, Asthma Quality of Life Questionnaire, and Asthma Self-Efficacy Scale). General Linear Models assessed associations between SES and each morbidity measure.</p> <p>Results</p> <p>Lower SES was associated with worse asthma control (F = 11.63, p < .001), greater emergency health service use (F = 5.09, p = .024), and worse asthma self-efficacy (F = 12.04, p < .01), independent of covariates. Logistic regression analyses revealed that patients with <12 years of education were 55% more likely to report an asthma-related emergency health service visit in the last year (OR = 1.55, 95%CI = 1.05-2.27). Lower SES was not related to worse asthma-related quality of life.</p> <p>Conclusions</p> <p>Results suggest that lower SES (measured according to education level), is associated with several indices of worse asthma morbidity, particularly worse asthma control, in adult asthmatics independent of disease severity. Results are consistent with previous studies linking lower SES to worse asthma in children, and add asthma to the list of chronic diseases affected by individual-level SES.</p

    Emergent Dark Matter, Baryon, and Lepton Numbers

    Get PDF
    We present a new mechanism for transferring a pre-existing lepton or baryon asymmetry to a dark matter asymmetry that relies on mass mixing which is dynamically induced in the early universe. Such mixing can succeed with only generic scales and operators and can give rise to distinctive relationships between the asymmetries in the two sectors. The mixing eliminates the need for the type of additional higher-dimensional operators that are inherent to many current asymmetric dark matter models. We consider several implementations of this idea. In one model, mass mixing is temporarily induced during a two-stage electroweak phase transition in a two Higgs doublet model. In the other class of models, mass mixing is induced by large field vacuum expectation values at high temperatures - either moduli fields or even more generic kinetic terms. Mass mixing models of this type can readily accommodate asymmetric dark matter masses ranging from 1 GeV to 100 TeV and expand the scope of possible relationships between the dark and visible sectors in such models.Comment: 36 pages, 5 figure

    Health status in COPD cannot be measured by the St George's Respiratory Questionnaire alone: an evaluation of the underlying concepts of this questionnaire

    Get PDF
    Contains fulltext : 88421.pdf (publisher's version ) (Open Access)BACKGROUND: Improving patients' health status is one of the major goals in COPD treatment. Questionnaires could facilitate the guidance of patient-tailored disease management by exploring which aspects of health status are problematic, and which aspects are not. Health status consists of four main domains (physiological functioning, symptoms, functional impairment, and quality of life), and at least sixteen sub-domains. A prerequisite for patient-tailored treatment is a detailed assessment of all these sub-domains. Most questionnaires developed to measure health status consist of one or a few subscales and measure merely some aspects of health status. The question then rises which aspects of health status are measured by these instruments, and which aspects are not covered. As it is one of the most frequently used questionnaires in COPD, we evaluated which aspects of health status are measured and which aspects are not measured by the St George's Respiratory Questionnaire (SGRQ). METHODS: One hundred and forty-six outpatients with COPD participated. Correlations were calculated between the three sections of the SGRQ and ten sub-domains of the Nijmegen Integral Assessment Framework, covering Symptoms, Functional Impairment, and Quality of Life. As the SGRQ was not expected to measure physiological functioning, we did not include this main domain in the statistical analyses. Pearson's r > or = 0.70 was used as criterion for conceptual similarity. RESULTS: The SGRQ sections Symptoms and Total showed conceptual similarity with the sub-domain Subjective Symptoms (main domain Symptoms). The sections Activity, Impacts and Total were conceptual similar to Subjective Impairment (main domain Functional Impairment). The SGRQ sections were not conceptual similar to other sub-domains of Symptoms, Functional Impairment, nor to any sub-domain of Quality of Life. CONCLUSIONS: The SGRQ could facilitate the guidance of disease management in COPD only partially. The SGRQ is appropriately only for measuring problems in the sub-domains Subjective Symptoms and Subjective Impairment, and not for measuring problems in other sub-domains of health status, such as Quality of Life

    Measurements of neutrino oscillation in appearance and disappearance channels by the T2K experiment with 6.6 x 10(20) protons on target

    Get PDF
    111 pages, 45 figures, submitted to Physical Review D. Minor revisions to text following referee comments111 pages, 45 figures, submitted to Physical Review D. Minor revisions to text following referee comments111 pages, 45 figures, submitted to Physical Review D. Minor revisions to text following referee commentsWe thank the J-PARC staff for superb accelerator performance and the CERN NA61/SHINE Collaboration for providing valuable particle production data. We acknowledge the support of MEXT, Japan; NSERC, NRC, and CFI, Canada; CEA and CNRS/IN2P3, France; DFG, Germany; INFN, Italy; National Science Centre (NCN), Poland; RSF, RFBR and MES, Russia; MINECO and ERDF funds, Spain; SNSF and SER, Switzerland; STFC, UK; and the U. S. Deparment of Energy, USA. We also thank CERN for the UA1/NOMAD magnet, DESY for the HERA-B magnet mover system, NII for SINET4, the WestGrid and SciNet consortia in Compute Canada, GridPP, UK, and the Emerald High Performance Computing facility in the Centre for Innovation, UK. In addition, participation of individual researchers and institutions has been further supported by funds from ERC (FP7), EU; JSPS, Japan; Royal Society, UK; and DOE Early Career program, USA

    Measurement of the electron neutrino charged-current interaction rate on water with the T2K ND280 pi(0) detector

    Get PDF
    10 pages, 6 figures, Submitted to PRDhttp://journals.aps.org/prd/abstract/10.1103/PhysRevD.91.112010© 2015 American Physical Society11 pages, 6 figures, as accepted to PRD11 pages, 6 figures, as accepted to PRD11 pages, 6 figures, as accepted to PR

    Knowledge and attitudes of university students toward pandemic influenza: a cross-sectional study from Turkey

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>During an influenza pandemic, higher education institutions with large populations of young adults can become serious outbreak centers. Since outbreak management is essential to disease control, we aimed to examine university students' knowledge of and attitudes toward the pandemic influenza A/H1N1 and vaccination and other preventive measures.</p> <p>Methods</p> <p>A cross-sectional study was conducted among 402 first year university students at Yeditepe University in Istanbul, Turkey between 1<sup>st </sup>and 30<sup>th </sup>of November 2009. Data regarding socio-demographic characteristics of the students, perceptions, level of knowledge and attitudes toward influenza pandemic and prevention measures were collected by means of a self-administered questionnaire. The questionnaire was distributed by the students affiliated with SANITAS, a university club of students in health related sciences.</p> <p>Results</p> <p>25.1% (101/402) of the study group perceived their personal risk of influenza as "high", while 40.5% (163/402) perceived it as "moderate", 20.6% (107/402) viewed it as "low" and 7.7% (31/402) indicated that it was "unknown". The risk perception of males was significantly lower than that of females (p = 0.004) and the risk perception among the students of health sciences was significantly lower than that of students of other sciences (p = 0.037). Within the study group, 72.1% (290/402) indicated that their main information source regarding H1N1 was the mass media. Health sciences students tended to rely more on the internet as an information source than other students (p = 0.015). The vast majority (92.8%; 373/402) of those interviewed indicated that they would not be vaccinated. The major concerns regarding vaccination had to do with the safety and side effects of the vaccine. Most of the participants (343/402, 85.3%) were carrying out one of prevention measures and the vast majority believed that hand washing, face mask and quarantina were effective measures for prevention.</p> <p>Conclusion</p> <p>The participants had enough knowledge about H1N1 pandemic about the disease although there were still gaps and confusions in some areas. In the future, when planning management strategies regarding pandemics or outbreaks in higher education institutions, new strategies should be developed to promote positive health behaviour among university students compatible with the international guidelines. Main information source is mass media, so it seems that new policies must be developed to attract attention of students to use different and more scientific-based information sources.</p

    "A renewed sense of purpose": mothers' and fathers' experience of having a child following a recent stillbirth.

    Get PDF
    Most research has focused on mothers' experiences of perinatal loss itself or on the subsequent pregnancy, whereas little attention has been paid to both parents' experiences of having a child following late perinatal loss and the experience of parenting this child. The current study therefore explored mothers' and fathers' experiences of becoming a parent to a child born after a recent stillbirth, covering the period of the second pregnancy and up to two years after the birth of the next baby. In depth interviews were conducted with 7 couples (14 participants). Couples were eligible if they previously had a stillbirth (after 24 weeks of gestation) and subsequently had another child (their first live baby) who was now under the age of 2 years. Couples who had more than one child after experiencing a stillbirth and those who were not fluent in English were excluded. Qualitative analysis of the interview data was conducted using Interpretive Phenomenological Analysis. Five superordinate themes emerged from the data: Living with uncertainty; Coping with uncertainty; Relationship with the next child; The continuing grief process; Identity as a parent. Overall, fathers' experiences were similar to those of mothers', including high levels of anxiety and guilt during the subsequent pregnancy and after the child was born. Coping strategies to address these were identified. Differences between mothers and fathers regarding the grief process during the subsequent pregnancy and after their second child was born were identified. Despite difficulties with bonding during pregnancy and at the time when the baby was born, parents' perceptions of their relationship with their subsequent child were positive. Findings highlight the importance of tailoring support systems not only according to mothers' but also to fathers' needs. Parents', and particularly fathers', reported lack of opportunities for grieving as well as the high level of anxiety of both parents about their baby's wellbeing during pregnancy and after birth implies a need for structured support. Difficulties experienced in bonding with the subsequent child during pregnancy and once the child is born need to be normalised

    Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

    Get PDF
    Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy

    Methamphetamine Inhibits the Glucose Uptake by Human Neurons and Astrocytes: Stabilization by Acetyl-L-Carnitine

    Get PDF
    Methamphetamine (METH), an addictive psycho-stimulant drug exerts euphoric effects on users and abusers. It is also known to cause cognitive impairment and neurotoxicity. Here, we hypothesized that METH exposure impairs the glucose uptake and metabolism in human neurons and astrocytes. Deprivation of glucose is expected to cause neurotoxicity and neuronal degeneration due to depletion of energy. We found that METH exposure inhibited the glucose uptake by neurons and astrocytes, in which neurons were more sensitive to METH than astrocytes in primary culture. Adaptability of these cells to fatty acid oxidation as an alternative source of energy during glucose limitation appeared to regulate this differential sensitivity. Decrease in neuronal glucose uptake by METH was associated with reduction of glucose transporter protein-3 (GLUT3). Surprisingly, METH exposure showed biphasic effects on astrocytic glucose uptake, in which 20 µM increased the uptake while 200 µM inhibited glucose uptake. Dual effects of METH on glucose uptake were paralleled to changes in the expression of astrocytic glucose transporter protein-1 (GLUT1). The adaptive nature of astrocyte to mitochondrial β-oxidation of fatty acid appeared to contribute the survival of astrocytes during METH-induced glucose deprivation. This differential adaptive nature of neurons and astrocytes also governed the differential sensitivity to the toxicity of METH in these brain cells. The effect of acetyl-L-carnitine for enhanced production of ATP from fatty oxidation in glucose-free culture condition validated the adaptive nature of neurons and astrocytes. These findings suggest that deprivation of glucose-derived energy may contribute to neurotoxicity of METH abusers
    corecore