403 research outputs found

    Pattern of ocular morbidity in pediatrics age group in a tertiary centre in western Nepal

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    Introduction: Ocular morbidities are importantbecause of their impact on child’s development,education and future work. Ocular morbidities in children may not be diagnosed and treated in time due to inability to express their problems which leads to amblyopia by the time they can express it. This study was conducted with an objective to determine the pattern of ocular morbidity in children less than and equal to 14 years of age presenting in the Outpatient Department (OPD) of Gandaki Medical College, Pokhara. Materials/ Methods: This is a cross sectional observational study where we reviewed the profile of all of all patients of age group equal to or less than 14 years entering eye OPD from September 2016 to September 2018 for eye examination. Result: A total of 1471 patients presented to eye department of GMC. The mean age of the patient was 8.25 ±4.24 years among which 57.8% were males and 42.2% were females. Maximum number of the patients were in age group 11 to 14 years (38.1%) while minimum number of the patients were in the age group <1 year(10.6%).Conjunctival disorders (23.9%) was the most common ocular morbidity followed by refractive error in (18.2%), miscellaneous conditions (10.4%), eyelid diseases (8.6%), lacrimal system diseases (7.8%). Conclusion: Thestudy gives a picture and pattern of ocular diseases in pediatrics age group which not only helps in early diagnosis and treatment of ocular diseases but also in decreasing the magnitude of childhood blindness and amblyopia

    Pressure-Induced Effects on the Structure of the FeSe Superconductor

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    A polycrystalline sample of FeSe, which adopts the tetragonal PbO-type structure (P4/nmm) at room temperature, has been prepared using solid state reaction. We have investigated pressure-induced structural changes in tetragonal FeSe at varying hydrostatic pressures up to 0.6 GPa in the orthorhombic (T = 50 K) and tetragonal (T = 190 K) phases using high resolution neutron powder diffraction. We report that the structure is quite compressible with a Bulk modulus around 31 GPa to 33 GPa and that the pressure response is anisotropic with a larger compressibility along the c-axis. Key bond angles of the SeFe4 pyramids and FeSe4 tetrahedra are also determined as a function of pressure

    Nonlinear lattice dynamics as a basis for enhanced superconductivity in YBa2Cu3O6.5

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    THz-frequency optical pulses can resonantly drive selected vibrational modes in solids and deform their crystal structure. In complex oxides, this method has been used to melt electronic orders, drive insulator to metal transitions or induce superconductivity. Strikingly, coherent interlayer transport strongly reminiscent of superconductivity can be transiently induced up to room temperature in YBa2Cu3O6+x. By combining femtosecond X-ray diffraction and ab initio density functional theory calculations, we determine here the crystal structure of this exotic non-equilibrium state. We find that nonlinear lattice excitation in normal-state YBa2Cu3O6+x at 100 K causes a staggered dilation/contraction of the Cu-O2 intra/inter- bilayer distances, accompanied by anisotropic changes in the in-plane O-Cu-O bond buckling. Density functional theory calculations indicate that these motions cause dramatic changes in the electronic structure. Amongst these, the enhancement in the dx2-y2 character of the in-plane electronic structure is likely to favor superconductivity.Comment: 28 pages, including Supplemen

    Tacit networks, crucial care: Informal networks and disaster response in Nepal's 2015 Gorkha earthquake

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    It is often reiterated that a better understanding of local networks and needs is key to risk reduction. Nevertheless, the crucial role of informal social networks and actors in the catering for human needs in disaster circumstances remains largely under-explored. If we have to rethink the ‘work’ that informality does for our understanding of urban areas, its contribution to resilience, and take it seriously in the ‘full spectrum of risk’ in urban and peri-urban centres, better and more balanced methods are needed. This paper attends to this gap. Examining the mechanisms of aid provision in the aftermath of the 2015 Gorkha Earthquake in Nepal, it details an experimental set of quantitative research methods to explore the role of informal social networks in the provision of critical human needs in natural disasters. Relying on a sample of 160 households across four districts and 16 villages in the built environment affected by the Gorkha earthquake, the paper reveals that, overall, a wide disparity exists in the comparative importance of organisations in the provision of aid and resources. Much crucial after-disaster care is catered for by a mix of relatives, temples, friends, neighbours and local clubs. It highlights the importance of informal networks in understanding, and theorising, governance (of disaster and of the ‘urban’ more in general), and calls for greater attention to its role. It is time, it argues, to revalue informal disaster governance networks as a crucial, not tacit, component of disaster response

    Limit on Continuous Neutrino Emission from Neutron Stars

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    The timing data of the binary pulsar PSR1913+16, are used to establish an upper limit on the rate of continuous neutrino emission from neutron stars. Neutrino emission from each of the neutron stars of the binary system, increases the star binding energy and thus translates to a decrease in their masses. This in turn implies an increase with time of the binary period. Using the pulsar data we obtain an upper limit on the allowed rate of mass reduction : ∣M˙∣<1.1×10−12yr−1M| \dot{M}| <1.1 \times 10^{-12} yr^{-1} M , where MM is the total mass of the binary. This constrains exotic nuclear equations of state that predict continuous neutrino emissions. The limit applies also to other channels of energy loss, e.g. axion emission. Continued timing measurements of additional binary pulsars, should yield a stronger limit in the future.Comment: 5 pages, Added a section on energy transport in the neutron star, JHEP publishe

    UBC-Nepal Expedition: An experimental overview of the 2016 University of British Columbia Scientific Expedition to Nepal Himalaya

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    The University of British Columbia Nepal Expedition took place over several months in the fall of 2016 and was comprised of an international team of 37 researchers. This paper describes the objectives, study characteristics, organization and management of this expedition, and presents novel blood gas data during acclimatization in both lowlanders and Sherpa. An overview and framework for the forthcoming publications is provided. The expedition conducted 17 major studies with two principal goals—to identify physiological differences in: 1) acclimatization; and 2) responses to sustained high-altitude exposure between lowland natives and people of Tibetan descent. We performed observational cohort studies of human responses to progressive hypobaric hypoxia (during ascent), and to sustained exposure to 5050 m over 3 weeks comparing lowlander adults (n = 30) with Sherpa adults (n = 24). Sherpa were tested both with (n = 12) and without (n = 12) descent to Kathmandu. Data collected from lowlander children (n = 30) in Canada were compared with those collected from Sherpa children (n = 57; 3400–3900m). Studies were conducted in Canada (344m) and the following locations in Nepal: Kathmandu (1400m), Namche Bazaar (3440m), Kunde Hospital (3480m), Pheriche (4371m) and the Ev-K2-CNR Research Pyramid Laboratory (5050m). The core studies focused on the mechanisms of cerebral blood flow regulation, the role of iron in cardiopulmonary regulation, pulmonary pressures, intra-ocular pressures, cardiac function, neuromuscular fatigue and function, blood volume regulation, autonomic control, and micro and macro vascular function. A total of 335 study sessions were conducted over three weeks at 5050m. In addition to an overview of this expedition and arterial blood gas data from Sherpa, suggestions for scientists aiming to perform field-based altitude research are also presented. Together, these findings will contribute to our understanding of human acclimatization and adaptation to the stress of residence at high-altitude

    JLab Measurement of the 4^4He Charge Form Factor at Large Momentum Transfers

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    The charge form factor of ^4He has been extracted in the range 29 fm−2^{-2} ≤Q2≤77\le Q^2 \le 77 fm−2^{-2} from elastic electron scattering, detecting 4^4He nuclei and electrons in coincidence with the High Resolution Spectrometers of the Hall A Facility of Jefferson Lab. The results are in qualitative agreement with realistic meson-nucleon theoretical calculations. The data have uncovered a second diffraction minimum, which was predicted in the Q2Q^2 range of this experiment, and rule out conclusively long-standing predictions of dimensional scaling of high-energy amplitudes using quark counting.Comment: 4 pages, 2 figure

    JLab Measurements of the 3He Form Factors at Large Momentum Transfers

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    The charge and magnetic form factors, FC and FM, of 3He have been extracted in the kinematic range 25 fm-2 < Q2 < 61 fm-2 from elastic electron scattering by detecting 3He recoil nuclei and electrons in coincidence with the High Resolution Spectrometers of the Hall A Facility at Jefferson Lab. The measurements are indicative of a second diffraction minimum for the magnetic form factor, which was predicted in the Q2 range of this experiment, and of a continuing diffractive structure for the charge form factor. The data are in qualitative agreement with theoretical calculations based on realistic interactions and accurate methods to solve the three-body nuclear problem

    Search for a new gauge boson in the A′A' Experiment (APEX)

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    We present a search at Jefferson Laboratory for new forces mediated by sub-GeV vector bosons with weak coupling α′\alpha' to electrons. Such a particle A′A' can be produced in electron-nucleus fixed-target scattering and then decay to an e+e−e^+e^- pair, producing a narrow resonance in the QED trident spectrum. Using APEX test run data, we searched in the mass range 175--250 MeV, found no evidence for an A′→e+e−A'\to e^+e^- reaction, and set an upper limit of α′/α≃10−6\alpha'/\alpha \simeq 10^{-6}. Our findings demonstrate that fixed-target searches can explore a new, wide, and important range of masses and couplings for sub-GeV forces.Comment: 5 pages, 5 figures, references adde
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