8,702 research outputs found

    Determining the sign of Δ31\Delta_{31} at long baseline neutrino experiments

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    Recently it is advocated that high intensity and low energy (Eν2GeV)(E_\nu \sim 2 GeV) neutrino beams should be built to probe the (13)(13) mixing angle ϕ\phi to a level of a few parts in 10410^4. Experiments using such beams will have better signal to background ratio in searches for νμνe\nu_\mu \to \nu_e oscillations. We propose that such experiments can also determine the sign of Δ31\Delta_{31} even if the beam consists of {\it neutrinos} only. By measuring the νμνe\nu_\mu \to \nu_e transitions in two different energy ranges, the effects due to propagation of neutrinos through earth's crust can be isolated and the sign of Δ31\Delta_{31} can be determined. If the sensitivity of an experiment to ϕ\phi is ϵ\epsilon, then the same experiment is automatically sensitive to matter effects and the sign of Δ31\Delta_{31} for values of ϕ2ϵ\phi \geq 2 \epsilon.Comment: Title changed and paper rewritten. 4 pages, 1 figure, revte

    Self similar Barkhausen noise in magnetic domain wall motion

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    A model for domain wall motion in ferromagnets is analyzed. Long-range magnetic dipolar interactions are shown to give rise to self-similar dynamics when the external magnetic field is increased adiabatically. The power spectrum of the resultant Barkhausen noise is of the form 1/ωα1/\omega^\alpha, where α1.5\alpha\approx 1.5 can be estimated from the critical exponents for interface depinning in random media.Comment: 7 pages, RevTex. To appear in Phys. Rev. Let

    Probing the matter term at long baseline experiments

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    We consider (\nu_\mu --> \nu_e) oscillations in long baseline experiments within a three flavor framework. A non-zero measurement of this oscillation probability implies that the (13) mixing angle `phi' is non-zero. We consider the effect of neutrino propagation through the matter of earth's crust and show that, given the constraints from solar neutrino and CHOOZ data, matter effects enhance the mixing for neutrinos rather than for anti-neutrinos. We need data from two different experiments with different baseline lengths (such as K2K and MINOS) to distinguish matter effects unambiguously.Comment: 9 pages including three figure

    The slimming effect of advection on black-hole accretion flows

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    At super-Eddington rates accretion flows onto black holes have been described as slim (aspect ratio H/R1H/R \lesssim 1) or thick (H/R >1) discs, also known as tori or (Polish) doughnuts. The relation between the two descriptions has never been established, but it was commonly believed that at sufficiently high accretion rates slim discs inflate, becoming thick. We wish to establish under what conditions slim accretion flows become thick. We use analytical equations, numerical 1+1 schemes, and numerical radiative MHD codes to describe and compare various accretion flow models at very high accretion rates.We find that the dominant effect of advection at high accretion rates precludes slim discs becoming thick. At super-Eddington rates accretion flows around black holes can always be considered slim rather than thick.Comment: 8 pages, 5 figures. Astronomy & Astrophysics, in pres

    Phase cascade bridge rectifier array in a 2-D lattice

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    We report on a novel rectification phenomenon in a 2-D lattice network consisting of N×N sites with diode and AC source elements with controllable phases. A phase cascade configuration is described in which the current ripple in a load resistor goes to zero in the large N limit, enhancing the rectification efficiency without requiring any external capacitor or inductor based filters. The integrated modular configuration is qualitatively different from conventional rectenna arrays in which the source, rectifier and filter systems are physically disjoint. Exact analytical results derived using idealized diodes are compared to a realistic simulation of commercially available diodes. Our results on nonlinear networks of source-rectifier arrays are potentially of interest to a fast evolving field of distributed power networks

    A late time acceleration of the universe with two scalar fields : many possibilities

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    In the present work, an attempt has been made to explain the recent cosmic acceleration with two mutually interacting scalar fields, one being the Brans-Dicke scalar field and the other a quintessence scalar field. Conditions have been derived for which the quintessence scalar field has an early oscillation and it grows during a later time to govern the dynamics of the universe.Comment: 8 pages, no figures. Accepted for publication in Mod. Phys. Lett.

    Распространенность остеопороза в сельских районах Южной Индии и его связь с общими вторичными факторами риска

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    Background. Osteoporosis is a common metabolic disorder characterised by decreased bone mass and weakened micro-architecture of bone tissue. After 50 years of age, one in three women and one in five men experience osteoporotic fractures. This is projected to cause a yearly loss of 5.8 million healthy life years to disability. The number of patients who attend the outpatient clinic and emergency department of Sanjay Gandhi Institute of Trauma and Orthopaedics with fragility fractures has been increasing, hence to know the prevalence of osteoporosis in the general population who were asymptomatic, we decided to conduct a study in the rural areas of south India. Aims: 1) to estimate the prevalence of osteoporosis among the population above 50 years in rural areas of south India; 2) to determine the correlation between common secondary risk factors for osteoporosis like tobacco consumption, alcohol, diabetes, and hypertension. Results. The prevalence of osteoporosis in the rural population was more in females at 42.2%, whereas the males had a prevalence of 32.5%. Among the population with habits of tobacco consumption and alcohol consumption, the prevalence was 78% and 30.6% respectively. 20.2% of non-smokers and 39.7% of non-alcoholics were osteoporotic. Among the population with comorbidities, 53.6% of diabetes and 55.4% of hypertensives were osteoporotic. 33.7% of non-diabetics were osteoporotic, and 29.5% of hypertensives were osteoporotic. The correlation between osteoporosis and the individual risk factors ranged between weak negative to moderately positive (r = -0.2 to 0.5). The correlation between the combination of all the four risk factors and osteoporosis is weakly positive (r = 0.339), which is highly significant (p0.001). Conclusion. Overall, the findings of this study suggest that addictive habits such as tobacco and alcohol consumption may have a significant impact on bone health, with a higher prevalence of osteopenia and osteoporosis observed in individuals with these habits. Comorbidities such as diabetes and hypertension were also found to be associated with a higher prevalence of osteoporosis. These findings emphasize the importance of early detection and prevention of addictive habits and comorbidities to reduce the risk of osteopenia and osteoporosis. Furthermore, the study highlights the need for further research to fully understand the complex relationships between sociodemographic factors, addictive habits, comorbidities, and bone health.Актуальность. Остеопороз распространенное метаболическое расстройство, характеризующееся уменьшением массы костной ткани и ослаблением микроархитектуры костей. После 50 лет каждая третья женщина и каждый пятый мужчина сталкиваются с остеопоротическими переломами. Это приводит к ежегодной потере 5,8 млн лет здоровой жизни (HLY) из-за инвалидности. Количество пациентов, обращающихся в поликлинику и отделение неотложной помощи Института травматологии и ортопедии им. Санджая Ганди с патологическими переломами, из года в год увеличивается. Чтобы определить распространенность остеопороза среди населения, не имеющего симптомов данного заболевания, мы решили провести исследование в сельских районах Южной Индии. Цели исследования: 1) оценить распространенность остеопороза среди населения старше 50 лет в сельских районах Южной Индии; 2) определить связь между общими вторичными факторами риска остеопороза, такими как употребление табака и алкоголя, диабет, гипертония. Результаты. Распространенность остеопороза в сельских районах была выше у женщин и составила 42,2%, в то время как у мужчин распространенность составила 32,5%. Среди лиц, употребляющих табак и алкоголь, распространенность составила 78,0% и 30,6% соответственно. Остеопороз был выявлен у 20,2% некурящих и у 39,7% не употребляющих алкоголь. Среди лиц с сопутствующими заболеваниями остеопороз выявлен у 53,6% диабетиков и 55,4% гипертоников. Связь между остеопорозом и отдельными факторами риска колебалась от слабо отрицательной до умеренно положительной (r = -0,2 до 0,5). Связь между комбинацией всех четырех факторов риска и остеопорозом была слабо положительной (r = 0,339) и имела высокую значимость (p0,001). Заключение. Результаты данного исследования свидетельствуют о значительном влиянии вредных привычек, таких как употребление табака и алкоголя, на здоровье костей, с более высокой распространенностью остеопении и остеопороза у лиц с этими привычками. Сопутствующие заболевания, такие как диабет и гипертония, также связаны с более высокой распространенностью остеопороза. Эти свидетельствует о важности раннего выявления сопутствующих заболеваний и отказа от вредных привычек для снижения риска развития остеопении и остеопороза. Необходимы дальнейшие исследования для полного понимания сложных взаимосвязей между социодемографическими факторами, привычками, сопутствующими заболеваниями и здоровьем костей

    In-situ integrated processing and characterization of thin films of high temperature superconductors, dielectrics and semiconductors by MOCVD

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    In this strategy of depositing the basic building blocks of superconductors, semiconductors, and dielectric having common elements, researchers deposited superconducting films of Y-Ba-Cu-O, semiconductor films of Cu2O, and dielectric films of BaF2 and Y2O3 by metal oxide chemical vapor deposition (MOCVD). By switching source materials entering the chamber, and by using direct writting capability, complex device structures like three-terminal hybrid semiconductors/superconductors transistors can be fabricated. The Y-Ba-Cu-O superconducting thin films on BaF2/YSZ substrates show a T(sub c) of 80 K and are textured with most of the grains having their c-axis or a-axis perpendicular to the substrate. Electrical characteristics as well as structural characteristics of superconductors and related materials obtained by x-ray defraction, electron microscopy, and energy dispersive x-ray analysis are discussed
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