844 research outputs found

    Laser-induced desorption of Na-dimers

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    Study of the characteristics of GEM detectors for the future FAIR experiment CBM

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    Characteristics of triple GEM detector have been studied systematically. The variation of the effective gain and energy resolution of GEM with variation of the applied voltage has been measured with Fe55 X-ray source for different gas mixtures and with different gas flow rates. Long-term test of the GEM has also been performed.Comment: 2 Pages, 6 figure

    Size effects in ion-neutral complex-mediated alkane eliminations from ionized aliphatic ethers

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    AbstractThe effects of the size of the ionic and neutral partners on ion-neutral complex-mediated alkane eliminations from ionized aliphatic ethers were determined by obtaining metastable decomposition spectra and photoionization ionization efficiency curves. Increasing the size of the ionic partner decreases the competitiveness of alkane elimination with alkyl loss. This is attributed to decreasing attraction between the partners with increasing distance between the neutral partner and the center of charge in the associated ion. Increasing the size of the neutral partner lowers the threshold for alkane elimination relative to that for simple dissociation when the first threshold is above ΔHf(products). This is attributed to increasing attraction between the partners with increasing polarizability of the radical in the complex. Adding a CH2 to the radical in a complex seems to increase the attraction between the partners by about 24 kJ mol−1

    Carbohydrates – Guidelines on Parenteral Nutrition, Chapter 5

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    The main role of carbohydrates in the human body is to provide energy. Carbohydrates should always be infused with PN (parenteral nutrition) in combination with amino acids and lipid emulsions to improve nitrogen balance. Glucose should be provided as a standard carbohydrate for PN, whereas the use of xylite is not generally recommended. Fructose solutions should not be used for PN. Approximately 60% of non-protein energy should be supplied as glucose with an intake of 3.0–3.5 g/kg body weight/day (2.1–2.4 mg/kg body weight/min). In patients with a high risk of hyperglycaemia (critically ill, diabetes, sepsis, or steroid therapy) an lower initial carbohydrate infusion rate of 1–2 g/kg body weight/day is recommended to achieve normoglycaemia. One should aim at reaching a blood glucose level of 80–110 mg/dL, and at least a glucose level <145 mg/dL should be achieved to reduce morbidity and mortality. Hyperglycaemia may require addition of an insulin infusion or a reduction (2.0–3.0 g/kg body weight/day) or even a temporary interruption of glucose infusion. Close monitoring of blood glucose levels is highly important

    The reliability of eyetracking to assess attentional bias to threatening words in healthy individuals

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    Eyetracking is commonly used to investigate attentional bias. Although some studies have investigated the internal consistency of eyetracking, data are scarce on the test–retest reliability and agreement of eyetracking to investigate attentional bias. This study reports the test–retest reliability, measurement error, and internal consistency of 12 commonly used outcome measures thought to reflect the different components of attentional bias: overall attention, early attention, and late attention. Healthy participants completed a preferential-looking eyetracking task that involved the presentation of threatening (sensory words, general threat words, and affective words) and nonthreatening words. We used intraclass correlation coefficients (ICCs) to measure test–retest reliability (ICC \u3e .70 indicates adequate reliability). The ICCs(2, 1) ranged from –.31to.71. Reliability varied according to the outcome measure and threat word category. Sensory words had a lower mean ICC (.08) than either affective words (.32) or general threat words (.29). A longer exposure time was associated with higher test–retest reliability. All of the outcome measures, except second-run dwell time, demonstrated low measurement error (\u3c6%). Most of the outcome measures reported high internal consistency (α \u3e.93). Recommendations are discussed for improving the reliability of eyetracking tasks in future research

    A systematic review highlights the need to improve the quality and applicability of trials of physical therapy interventions for low back pain

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    Objectives: The objective of this study was to review and assess the methodological quality of randomized controlled trials that test physical therapy interventions for low back pain. Study Design and Setting: This is a systematic review of trials of physical therapy interventions to prevent or treat low back pain (of any duration or type) in participants of any age indexed on the Physiotherapy Evidence Database (PEDro). Existing PEDro scale ratings were used to evaluate methodological quality. Results: This review identified 2,215 trials. The majority of trials were for adults (n = 2136, 96.4%), low back pain without specific etiology (n = 1,863, 84.1%), and chronic duration (n = 947, 42.8%). The quality of trials improved over time; however, most were at risk of bias. Less than half of the trials concealed allocation to intervention (n = 813, 36.7%), used intention-to-treat principles (n = 778, 35.1%), and blinded assessors (n = 810, 36.6%), participants (n = 174, 7.9%), and therapists (n = 39, 1.8%). These findings did not vary by the type of therapy. Conclusion: Most trials that test physical therapy interventions for low back pain have methodological limitations that could bias treatment effect estimates. Greater attention to methodological features, such as allocation concealment and the reporting of intention-to-treat effects, would improve the quality of trials testing physical therapy interventions for low back pain

    Viral hepatitis testing and treatment in community pharmacies:a systematic review and meta-analysis

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    Background: The World Health Organization seeks to eliminate viral hepatitis as a public health threat by 2030. This review and meta-analysis aims to evaluate the effectiveness of programs for hepatitis B and C testing and treatment in community pharmacies. Methods: Medline, Embase, Cochrane CENTRAL, and Global Health were searched from database inception until 12 November 2023. Comparative and single arm intervention studies were eligible for inclusion if they assessed delivery of any of the following interventions for hepatitis B or C in pharmacies: (1) pre-testing risk assessment, (2) testing, (3) pre-treatment assessment or (4) treatment. Primary outcomes were proportions testing positive and reaching each stage in the cascade. Random effects meta-analysis was used to estimate pooled proportions stratified by recruitment strategy and setting where possible; other results were synthesised narratively. This study was pre-registered (PROSPERO: CRD42022324218). Findings: Twenty-seven studies (4 comparative, 23 single arm) were included, of which 26 reported hepatitis C outcomes and four reported hepatitis B outcomes. History of injecting drug use was the most identified risk factor from pre-testing risk assessments. The pooled proportion hepatitis C antibody positive from of 19 studies testing 5096 participants was 16.6% (95% CI 11.0%–23.0%; heterogeneity I 2 = 96.6%). The pooled proportion antibody positive was significantly higher when testing targeted people with specified risk factors (32.5%, 95% CI 24.8%–40.6%; heterogeneity I 2 = 82.4%) compared with non-targeted or other recruitment methods 4.0% (95% CI 2.1%–6.5%; heterogeneity I 2 = 83.5%). Meta-analysis of 14 studies with 813 participants eligible for pre-treatment assessment showed pooled attendance rates were significantly higher in pharmacies (92.7%, 95% CI 79.1%–99.9%; heterogeneity I 2 = 72.4%) compared with referral to non-pharmacy settings (53.5%, 95% CI 36.5%–70.1%; heterogeneity I 2 = 92.3%). The pooled proportion initiating treatment was 85.6% (95% CI 74.8%–94.3%; heterogeneity I 2 = 75.1%). This did not differ significantly between pharmacy and non-pharmacy settings. Interpretation: These findings add pharmacies to the growing evidence supporting community-based testing and treatment for hepatitis C. Few comparative studies and high degrees of statistical heterogeneity were important limitations. Hepatitis B care in pharmacies presents an opportunity for future research. Funding: None.</p

    Sagnac Interferometer as a Speed-Meter-Type, Quantum-Nondemolition Gravitational-Wave Detector

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    According to quantum measurement theory, "speed meters" -- devices that measure the momentum, or speed, of free test masses -- are immune to the standard quantum limit (SQL). It is shown that a Sagnac-interferometer gravitational-wave detector is a speed meter and therefore in principle it can beat the SQL by large amounts over a wide band of frequencies. It is shown, further, that, when one ignores optical losses, a signal-recycled Sagnac interferometer with Fabry-Perot arm cavities has precisely the same performance, for the same circulating light power, as the Michelson speed-meter interferometer recently invented and studied by P. Purdue and the author. The influence of optical losses is not studied, but it is plausible that they be fairly unimportant for the Sagnac, as for other speed meters. With squeezed vacuum (squeeze factor e−2R=0.1e^{-2R} = 0.1) injected into its dark port, the recycled Sagnac can beat the SQL by a factor 10≃3 \sqrt{10} \simeq 3 over the frequency band 10 {\rm Hz} \alt f \alt 150 {\rm Hz} using the same circulating power Ic∼820I_c\sim 820 kW as is used by the (quantum limited) second-generation Advanced LIGO interferometers -- if other noise sources are made sufficiently small. It is concluded that the Sagnac optical configuration, with signal recycling and squeezed-vacuum injection, is an attractive candidate for third-generation interferometric gravitational-wave detectors (LIGO-III and EURO).Comment: 12 pages, 6 figure
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