758 research outputs found

    A test of tau neutrino interactions with atmospheric neutrinos and K2K

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    The presence of a tau component in the flux of atmospheric neutrinos inside the Earth, due to flavor oscillations, makes these neutrinos a valuable probe of interactions of the tau neutrino with matter. We study -- analytically and numerically -- the effects of nonstandard interactions in the nu_e-nu_tau sector on atmospheric neutrino oscillations, and calculate the bounds on the exotic couplings that follow from combining the atmospheric neutrino and K2K data. We find very good agreement between numerical results and analytical predictions derived from the underlying oscillation physics. While improving on existing accelerator bounds, our bounds still allow couplings of the size comparable to the standard weak interaction. The inclusion of new interactions expands the allowed region of the vacuum oscillation parameters towards smaller mixing angles, 0.2 ~< sin^2 theta_{23} ~< 0.7, and slightly larger mass squared splitting, 1.5 * 10^{-3} eV^2 ~< |\Delta m^2_{23}| ~< 4.0 * 10^{-3} eV^2, compared to the standard case. The impact of the K2K data on all these results is significant; further important tests of the nu_e-nu_tau exotic couplings will come from neutrino beams experiments such as MINOS and long baseline projects.Comment: 8 figures, some typos corrected, minor editing in the reference

    Effect of screentime in college students during the COVID-19 online classes on their neck posture and postural control: an observational study

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    Background: Corona virus which is the source of severe acute pulmonary syndrome causes an airway tract contamination (COVID 19). Prolonged sitting for online classes in the college students leads to the enlarged postural deviation, increased low back pain. Prolonged static contraction of skeletal muscles of the cervical region, lower back leads to impaired flow of blood to the muscle groups together with edema and accumulation of waste metabolites will trigger the muscle spasm. Methods: Total 30 college students aged between 18-25 years who attended the online classes during COVID-19 were included in this study by using a questionnaire. The outcome measures used were the measurement of CV angle, SEBT and BBS. The postural control was estimated by using star excursion balance test and Berg balance scale. Results: Using Karl Pearson’s correlation coefficient, a positive correlation was observed between CV angle and BBS (r = 0.82). Between BMI and CV angle there exists a statistically significant negative correlation (r = -0.564). Conclusions: This study proved that there exists a forward neck posture in the students who attended the online classes during the COVID-19 pandemic and that also affected their postural control

    Checklist of marine bivalves and gastropods off Kollam, Kerala

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    Species diversity of any region can be illustrated by means of an available checklist. It provides an overview of the species that have been recorded. and can be considered to understand the local fauna. Fortnightly surveys were carried out to collect the shell-molluscs samples during 2012 - 2014 period from the by-catch of shrimp/fish trawlers landed at Sakthikulangara-Neendakara Fishing Harbour, Kollam. Collected bivalves and gastropods included both empty shells and living animals. Collected shells were brought to the laboratory and placed in freezer for 24 hours. This would liquefy the mollusc body and allowed easy extraction with a strong jet of water

    Thermal expansion of doped lanthanum gallates

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    Thermal expansion of several compositions of Sr and Mg-doped LaGaO3 including an A-site deficient composition (La0.9Sr0.1)0.98(Ga0.8Mg0.2)O2.821 were measured in the temperature range from 298 to 1273 K. The effect of doping on thermal expansion was studied by varying the composition at one site of the perovskite structure (either A or B), while keeping the composition at the other site invariant. Thermal expansion varied nonlinearly with temperature and exhibited an inflexion between 550 and 620 K, probably related to the change in crystal structure from orthorhombic to rhombohedral. The dependence of average thermal expansion coefficient (α av) on the dopant concentration on either A or B site of the perovskite structure was found to be linear, when the composition at the other site was kept constant. Mg doping on the B-site had a greater effect on the average thermal expansion coefficient than Sr doping on the A-site. Cation deficiency at the A-site decreases thermal expansion when compositions at both sites are held constant

    Rare observation of scar-bearing cuttlebone in a wild-caught Sepia pharaonis (Cephalopoda: Sepiidae) from southeastern Arabian Sea

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    A rare observation of the severely fractured cum healing cuttlebone of wild-caught Sepia pharaonis is reported and discussed here. The observation showed that cuttlebone of one specimen was severely affected by scars. Scars were interpreted as oval-shaped teeth marks on the dorsal side having a diameter of 23 mm. Several other teeth marks (3-4 numbers) were also observed at the anterodorsal region. Fracture was completely healed at the dorsal side while fracture (19 mm length) was notable in posteroventral region. Inverted ‘V’shaped blackline was also observed on the posteroventral region. However, scar-bearing cuttlebones was more or less symmetrical with respect to the sagittal plane

    Scope for light assisted fishing in Southeastern Arabian Sea

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    Scope for light assisted fishing in Southeastern Arabian Se

    Mussel Culture

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    Mariculture of bivalves greater importance in meeting the increasing protein demands of the human population. Bivalve groups such as oyster, mussel and clam are the most important cultivable organisms all over the world. Of these, P. viridis andP.indica forms the most dominant cultivable species. The Central Marine Fisheries Research Institute (CMFRI) has developed eco-friendly techniques for mussel culture. Recently, CMFRI has taken up efforts to popularize mussel culture in all coastal districts of Kerala

    Rare occurrence of Reinhardt’s cranch squid Liocranchia reinhardti (Cephalopod: Cranchiidae) from southeastern Arabian Sea

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    Single individual of the rare cranchiid squid Liocranchia reinhardti belonging to the Cranchiidae family was caught in a bottom trawl operated at 80 m in southeastern Arabian Sea. The morphometric measurements and indices of the specimen are provided. Statolith microstructure analysis revealed that the L. reinhardti with 118 mm dorsal mantle length (DML) had an age of 71 days with growth rate of 1.66 mm DML/day

    Oyster Farming Techniques

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    Oysters, mussels, clams, scallops, cockles and abalones are major groups of molluscs which are cultured in different parts of the world. Edible oysters are the most important among them, as they are great delicacy and there is growing demand. There is an increasing interest in oyster culture in tropical countries in recent years. In India there is a growing demand for oyster meat in some parts of the country. They are highly esteemed sea food and considered a delicacy in USA, Europe, Japan etc. It is said that ‘oyster’ is scientifically the best known marine animal. It is one of the most widely cultivated species. As early as the first century BC the Romans were the first to develop simple methods of collecting oyster seeds and growing them for food

    Paralarva of the sharpear enope squid Ancistrocheirus lesueurii (Oegopsida: Ancistrocheiridae) in the southeastern Arabian Sea

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    First morphological description of an early stage paralarva of the sharpear enope squid Ancistrocheirus lesueurii from southeastern Arabian Sea is presented. The paralarva was collected at dusk by using surface tows of zooplankton nets in February 2012. The presence of paralarva A. lesueurii indicates that this species completes its life cycle in this sea. A comparison of the arm formula of paralarva and adult stages shows a major change in the formula during metamorphosis to adult
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