342 research outputs found

    Effect of buffer gases on the performance of SO2 trace measurement based on photoacoustic spectroscopy

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    In this experimental work a laser photoacoustic spectrometer designed and fabricated. System sensitivity for detection of SO2 and NO 2 was measured. Resonance frequency variation versus pressure increase of Nitrogen, Argon, Helium and Air buffer gases was studied. Results show that, sensitivity of system for SO2 and NO2 are 353 ppb and 963 ppb respectively. It was shown that resonance frequency for Nitrogen, Argon, and Air buffer gases was not noticeably varied by buffer gas pressure increasing, but for Helium, resonance frequency not only is not in range of three other gases, but also grows by pressure increasing. The system noises were damped preparing two buffer chambers. © 2014 Elsevier B.V. All rights reserved

    Transforming Growth Factor ÎČ Signaling Pathway Associated Gene Polymorphisms May Explain Lower Breast Cancer Risk in Western Indian Women

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    Transforming growth factor ÎČ1 (TGFB1) T29C and TGF ÎČ receptor type 1 (TGFBR1) 6A/9A polymorphisms have been implicated in the modulation of risk for breast cancer in Caucasian women. We analyzed these polymorphisms and combinations of their genotypes, in pre menopausal breast cancer patients (N = 182) and healthy women (N = 236) from western India as well as in breast cancer patients and healthy women from the Parsi community (N = 48 & 171, respectively). Western Indian women were characterized by a higher frequency of TGFB1*C allele of the TGF ÎČ T29C polymorphism (0.48 vs 0.44) and a significantly lower frequency of TGFBR1*6A allele of the TGFBR1 6A/9A polymorphism (0.02 vs 0.068, p<0.01) as compared to healthy Parsi women. A strong protective effect of TGFB1*29C allele was seen in younger western Indian women (<40 yrs; OR = 0.45, 95% CI 0.25–0.81). Compared to healthy women, the strikingly higher frequencies of low or intermediate TGF ÎČ signalers in patients suggested a strong influence of the combination of these genotypes on the risk for breast cancer in Parsi women (for intermediate signalers, OR = 4.47 95%CI 1.01–19.69). The frequency of low signalers in Parsi healthy women, while comparable to that reported in Europeans and Americans, was three times higher than that in healthy women from western India (10.6% vs 3.3%, p<0.01). These observations, in conjunction with the low incidence rate of breast cancer in Indian women compared to White women, raise a possibility that the higher frequency of TGFB1*29C allele and lower frequency of TGFBR1*6A allele may represent important genetic determinants that together contribute to a lower risk of breast cancer in western Indian women

    Wholesale pricing in a small open economy

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    This paper addresses the empirical analysis of wholesale profit margins using data of the Dutch wholesale sector, 1986. At the heart of the analysis is the typical nature of wholesale production: wholesalers do not produce a tangible product, but offer a service capacity. This has an immediate impact on the identification, interprelation and measurement of determinants of profit variations. A model is set up to explain variations in wholesale profit margins, which is inspired by two widely applied approaches to industry pricing: the behavioural mark-up model and the marginalist price-cost model

    Metabolic syndrome is linked to a mild elevation in liver aminotransferases in diabetic patients with undetectable non-alcoholic fatty liver disease by ultrasound

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    <p>Abstract</p> <p>Background</p> <p>Despite ongoing findings on the relationship between elevated levels of alanine and aspartate aminotransferases (ALT and AST) and metabolic syndrome (MetS), this association in diabetic patients without a known cause for liver enzymes elevation other than diabetes, per se, remains unclear. In this study, we aimed to assess the relationship between circulating liver enzymes and MetS in a relatively large sample of patients with diabetes.</p> <p>Methods</p> <p>A total of 670 diabetic patients, without known causes of hepatocellular injury, were enrolled. Patients with ultrasonographic signs of fatty liver disease were not included. Fasting blood samples were obtained and biochemical characteristics were measured. MetS was defined according to the international diabetes federation criteria.</p> <p>Results</p> <p>Serum ALT and AST were significantly higher in patients with MetS (p < 0.001). High waist circumference and low HDL-cholesterol were significantly associated with elevated ALT (OR = 2.56 and 2.0, respectively) and AST (OR = 2.23 and 2.21, respectively). ALT and AST were significantly associated with MetS (OR = 2.17 and 2.31, respectively). These associations remained significant after multiple adjustments for age, sex, BMI, diabetes duration, HbA1c and medications. There was a significant (p < 0.01) positive association between the number of the MetS features and the level of ALT or AST.</p> <p>Conclusion</p> <p>In diabetic patients without ultrasonographic evidence of fatty liver, elevated aminotransferases are independently associated with MetS. Despite negative ultrasound results in diabetic patients with MetS, the serum level of liver aminotransferases may be elevated and should be more thoroughly monitored.</p

    Re-examining the Unified Theory of Acceptance and Use of Technology (UTAUT): Towards a Revised Theoretical Model

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    YesBased on a critical review of the Unified Theory of Acceptance and Use of Technology (UTAUT), this study first formalized an alternative theoretical model for explaining the acceptance and use of information system (IS) and information technology (IT) innovations. The revised theoretical model was then empirically examined using a combination of meta-analysis and structural equation modelling (MASEM) techniques. The meta-analysis was based on 1600 observations on 21 relationships coded from 162 prior studies on IS/IT acceptance and use. The SEM analysis showed that attitude: was central to behavioural intentions and usage behaviours, partially mediated the effects of exogenous constructs on behavioural intentions, and had a direct influence on usage behaviours. A number of implications for theory and practice are derived based on the findings

    Third national surveillance of risk factors of non-communicable diseases (SuRFNCD-2007) in Iran: methods and results on prevalence of diabetes, hypertension, obesity, central obesity, and dyslipidemia

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    <p>Abstract</p> <p>Background</p> <p>The burden of non-communicable diseases is rising globally. This trend seems to be faster in developing countries of the Middle East. In this study, we presented the latest prevalence rates of a number of important non-communicable diseases and their risk factors in the Iranian population.</p> <p>Methods</p> <p>The results of this study are extracted from the third national Surveillance of Risk Factors of Non-Communicable Diseases (SuRFNCD-2007), conducted in 2007. A total of 5,287 Iranian citizens, aged 15–64 years, were included in this survey. Interviewer-administered questionnaires were applied to collect the data of participants including the demographics, diet, physical activity, smoking, history of hypertension, and history of diabetes. Anthropometric characteristics were measured and serum biochemistry profiles were determined on venous blood samples. Diabetes (fasting plasma glucose ≄ 126 mg/dl), hypertension (systolic blood pressure ≄ 140 mmHg, diastolic blood pressure ≄ 90 mmHg, or use of anti-hypertensive drugs), dyslipidemia (hypertriglyceridemia: triglycerides ≄ 150 mg/dl, hypercholesterolemia: total cholesterol ≄ 200 mg/dl), obesity (body mass index ≄ 30 kg/m<sup>2</sup>), and central obesity (waist circumference ≄ 80 cm in females and ≄ 94 cm in males) were identified and the national prevalence rates were estimated.</p> <p>Results</p> <p>The prevalence of diabetes, hypertension, obesity, and central obesity was 8.7% (95%CI = 7.4–10.2%), 26.6% (95%CI = 24.4–28.9%), 22.3% (95%CI = 20.2–24.5%), and 53.6% (95%CI = 50.4–56.8%), respectively. The prevalence of hypertriglyceridemia and hypercholesterolemia was 36.4% (95%CI = 34.1–38.9%) and 42.9% (95%CI = 40.4–45.4%), respectively. All of the mentioned prevalence rates were higher among females (except hypertriglyceridemia) and urban residents.</p> <p>Conclusion</p> <p>We documented a strikingly high prevalence of a number of chronic non-communicable diseases and their risk factors among Iranian adults. Urgent preventive interventions should be implemented to combat the growing public health problems in Iran.</p

    Observation of the Rare Decay of the η Meson to Four Muons

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    A search for the rare η→Ό+Ό−Ό+Ό− double-Dalitz decay is performed using a sample of proton-proton collisions, collected by the CMS experiment at the CERN LHC with high-rate muon triggers during 2017 and 2018 and corresponding to an integrated luminosity of 101  fb−1. A signal having a statistical significance well in excess of 5 standard deviations is observed. Using the η→Ό+Ό− decay as normalization, the branching fraction B(η→Ό+Ό−Ό+Ό−)=[5.0±0.8(stat)±0.7(syst)±0.7(B2ÎŒ)]×10−9 is measured, where the last term is the uncertainty in the normalization channel branching fraction. This work achieves an improved precision of over 5 orders of magnitude compared to previous results, leading to the first measurement of this branching fraction, which is found to agree with theoretical predictions

    Search for new physics in multijet events with at least one photon and large missing transverse momentum in proton-proton collisions at 13 TeV

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    A search for new physics in final states consisting of at least one photon, multiple jets, and large missing transverse momentum is presented, using proton-proton collision events at a center-of-mass energy of 13 TeV. The data correspond to an integrated luminosity of 137 fb−1, recorded by the CMS experiment at the CERN LHC from 2016 to 2018. The events are divided into mutually exclusive bins characterized by the missing transverse momentum, the number of jets, the number of b-tagged jets, and jets consistent with the presence of hadronically decaying W, Z, or Higgs bosons. The observed data are found to be consistent with the prediction from standard model processes. The results are interpreted in the context of simplified models of pair production of supersymmetric particles via strong and electroweak interactions. Depending on the details of the signal models, gluinos and squarks of masses up to 2.35 and 1.43 TeV, respectively, and electroweakinos of masses up to 1.23 TeV are excluded at 95% confidence level

    Search for a high-mass dimuon resonance produced in association with b quark jets at s \sqrt{s} = 13 TeV

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