5,764 research outputs found

    Bose-Einstein Correlations and Sonoluminescence

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    Sonoluminescence may be studied in detail by intensity correlations among the emitted photons. As an example, we discuss an experiment to measure the size of the light-emitting region by the Hanbury Brown-Twiss effect. We show that single bubble sonoluminescence is almost ideally suited for study by this method and that plausible values for the physical parameters are within easy experimental reach. A sequence of two and higher order photon correlation experiments is outlined.Comment: Latex File, 8 pages, Postscript file with 2 figs. attache

    Gravitational instability and star formation in disk galaxies

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    We present a general star formation law where star formation rate depends upon efficiency α\alpha, timescale τ\tau of star formation, gas component σg\sigma_{g} of surface mass density and a real exponent nn. A given exponent nn determines τ\tau which however yields the corresponding star formation rate. Current nominal Schmidt exponent nsn_{s} for our model is 2<ns<32<n_{s}<3. Based on a gravitational instability parameter QAQ_{A} and another dimensionless parameter fP(P/Gσc2)1/2f_{P}\equiv (P/G\sigma_{c}^{2})^{1/2}, where PP = pressure, σc\sigma_{c} = column density of molecular clouds, we suggest a general equation for star formation rate which depends upon relative competence of the two parameters for various physical circumstances. We find that QAQ_{A} emerges to be a better parameter for star formation scenario than Toomre Q-parameter. Star formation rate in the solar neighbourhood is found to be in good agreement with values inferred from previous studies. Under closed box approximation model, we obtain a relation between metallicity of gas and the efficiency of star formation. Our model calculations of metallicity in the solar neighbourhood agree with earlier estimates. We conclude that metallicity dispersion for stars of same age may result due to a change in efficiency through which different sample stars were processed. For no significant change of metallicity with age, we suggest that all sample stars were born with almost similar efficiency.Comment: 10 pages, 3 figures, submitted to MNRA

    Occurrence and incidence of foot rot disease on fenugreek caused by Fusarium moniliforme in Rohilkhand region of Uttar Pradesh, India

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    Pathological studies were carried out in Rohilkhand region during the crop season 2013-14 to assess the pathogenic disease incidence of foot rot of fenugreek (Trigonella foenum-graecum Linn.) caused by Fusarium moniliforme. A total of 75 fields were surveyed during the crop period at monthly interval during germination, vegetative, flowering and fruiting stages in five different localities of Rohilkhand region. The foot-rot disease of fenugreek was found in all fields (Bareilly, Baheri, Pilibhit, Budaun and Meerganj) selected for the study. Monthly occurrence of disease incidence of foot rot ranged from 44-58%. Maximum disease incidence was recorded in the month of Oct. (58%) followed by September (57%) and November (56%). January exhibited the lowest incidence (45%) of pathogenic disease. However, foot rot symptoms developed at early stage of plant growth and persisted up to the end of the crop

    Comparative clinical profile of patients of Benign Prostatic Hyperplasia (BPH) with and without Metabolic Syndrome: a prospective observational study

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    Background: Benign Prostatic Hyperplasia (BPH) is one of common disorder in men of old age group. The pathogenesis of BPH is multi-factorial and still not been fully elucidated. There are numerous reports which suggest possible link between several metabolic alterations known as Metabolic Syndrome. In the present study, the aim was to establish relation between Benign Prostatic Hyperplasia and Metabolic Syndrome and to find out effects of therapeutic intervention of Metabolic Syndrome on prostatic parameters.Methods: 93 patients of Benign Prostatic Hyperplasia enrolled who met qualifying criteria for inclusion in study and divided into three groups on the basis of Metabolic Syndrome and its treatment administered. Administration of alpha adrenergic blocker was common to all patients of all groups. Metabolic parameters including Fasting blood glucose, High-density lipoprotein (HDL), Triglycerides (TGs), waist circumference and prostatic parameters that is prostate volume, prostate specific antigen (PSA), uroflometry, International prostate symptom score (IPSS) were assessed at baseline, after 3 and 6 months follow-up. Further appropriate statistical tests were applied for comparison of parameters among groups.Results: Patients receiving no treatment for Metabolic Syndrome were having most deranged prostatic parameters as compared to patients without Metabolic Syndrome or patients with Metabolic Syndrome receiving treatment for same. Further patients receiving treatment for Metabolic Syndrome and alpha adrenergic blocker were having better clinical profile than patients of alpha adrenergic blocker alone.Conclusions: These findings show probable link between Metabolic Syndrome and worse prostatic profile. Metabolic Syndrome must be looked for and treated in patients of Benign Prostatic Hyperplasia. Metabolic derangements must not be overlooked and must be treated accordingly

    A comparison of clinical and radiological findings in adults and children with Japanese encephalitis

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    Background: Japanese encephalitis (JE) is the most common human endemic encephalitis, prevalent mainly in Southeast Asia. It affects both adults and children in different areas, but there is no comparative study of their clinical features and outcomes. Objective: To evaluate clinical and radiological features in adults and children with JE. Methods: Patients with serologically or virologically confirmed JE who were treated during the past 10 years were included in this study. All patients underwent a detailed neurological examination, computed tomography, or magnetic resonance imaging. The presence of movement disorders, anterior horn cell involvement, and electroencephalographic changes was noted. After 6 months, each patient's outcome was defined as poor, partial, or complete recovery. The clinical and radiological findings for both adults and children were compared using &#967;2 tests. Results: The results are based on 30 children and 37 adults. Seizure was present in 23 adults (62.2%) and in 17 children (56.7%). Three children had associated neurocysticercosis, and all of them had partial seizures. The occurrence of focal neurological deficit, anterior horn cell involvement, and parkinsonian features was not significantly different between adults and children. Dystonia was more common in children, occurring in 20 (66.7%) compared with 7 adults (18.9%). Six adults died, but none of the children did; however, the 6-month outcome was better for surviving adults compared with the children. Computed tomography and magnetic resonance imaging findings were not significantly different between the 2 groups. Conclusions: Children with JE are more likely to have dystonia and a poor outcome at 6 months compared with adults. The difference in clinical findings and outcome in children and adults with JE may be owing to immunological factors, maturation of the central nervous system, and neuronal plasticity

    Are We Seeing Magnetic Axis Reorientation in the Crab and Vela Pulsars?

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    Variation in the angle α\alpha between a pulsar's rotational and magnetic axes would change the torque and spin-down rate. We show that sudden increases in α\alpha, coincident with glitches, could be responsible for the persistent increases in spin-down rate that follow glitches in the Crab pulsar. Moreover, changes in α\alpha at a rate similar to that inferred for the Crab pulsar account naturally for the very low braking index of the Vela pulsar. If α\alpha increases with time, all pulsar ages obtained from the conventional braking model are underestimates. Decoupling of the neutron star liquid interior from the external torque cannot account for Vela's low braking index. Variations in the Crab's pulse profile due to changes in α\alpha might be measurable.Comment: 14 pages and one figure, Latex, uses aasms4.sty. Accepted to ApJ Letter
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