1,011 research outputs found

    Discriminating neutrino mass models using Type II seesaw formula

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    In this paper we propose a kind of natural selection which can discriminate the three possible neutrino mass models, namely the degenerate, inverted hierarchical and normal hierarchical models, using the framework of Type II seesaw formula. We arrive at a conclusion that the inverted hierarchical model appears to be most favourable whereas the normal hierarchical model follows next to it. The degenerate model is found to be most unfavourable. We use the hypothesis that those neutrino mass models in which Type I seesaw term dominates over the Type II left-handed Higgs triplet term are favoured to survive in nature.Comment: No change in the results, a few references added, some changes in Type[IIB] calculation

    Phenomenological Consequences of Singlet Neutrinos

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    In this paper, we study the phenomenology of right-handed neutrino isosinglets. We consider the general situation where the neutrino masses are not necessarily given by mD2/Mm_D^2/M, where mDm_D and MM are the Dirac and Majorana mass terms respectively. The consequent mixing between the light and heavy neutrinos is then not suppressed, and we treat it as an independent parameter in the analysis. It turns out that μe\mu-e conversion is an important experiment in placing limits on the heavy mass scale (MM) and the mixing. Mixings among light neutrinos are constrained by neutrinoless double beta decay, as well as by solar and atmospheric neutrino experiments. Detailed one-loop calculations for lepton number violating vertices are provided.Comment: Revtex file,TRI-PP-94-1,VPI-IHEP-94-1, 23 pages, a compressed for 8 figures is appende

    The CP-conserving two-Higgs-doublet model: the approach to the decoupling limit

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    A CP-even neutral Higgs boson with Standard-Model-like couplings may be the lightest scalar of a two-Higgs-doublet model. We study the decoupling limit of the most general CP-conserving two-Higgs-doublet model, where the mass of the lightest Higgs scalar is significantly smaller than the masses of the other Higgs bosons of the model. In this case, the properties of the lightest Higgs boson are nearly indistinguishable from those of the Standard Model Higgs boson. The first non-trivial corrections to Higgs couplings in the approach to the decoupling limit are also evaluated. The importance of detecting such deviations in precision Higgs measurements at future colliders is emphasized. We also clarify the case in which a neutral Higgs boson can possess Standard-Model-like couplings in a regime where the decoupling limit does not apply. The two-Higgs-doublet sector of the minimal supersymmetric model illustrates many of the above features.Comment: 54 pages, 2 tables, revtex4 format, some new material added (including elegant forms for the three-Higgs and four-Higgs couplings) and typographical errors fixe

    Stochastic evolution of cosmological parameters in the early universe

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    We develop a stochastic formulation of cosmology in the early universe, after considering the scatter in the redshift-apparent magnitude diagram in the early epochs as an observational evidence for the non-deterministic evolution of early universe. We consider the stochastic evolution of density parameter in the early universe after the inflationary phase qualitatively, under the assumption of fluctuating ww factor in the equation of state, in the Fokker-Planck formalism. Since the scale factor for the universe depends on the energy density, from the coupled Friedmann equations we calculated the two variable probability distribution function assuming a flat space geometry.Comment: 10 page

    Development of a Reference Set of Sorghum (\u3cem\u3eSorghum\u3c/em\u3e spp.) for Cyanogenic Potential (HCN-p) and Evaluating Their Fodder Yield Traits

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    Sorghum (Sorghum bicolor (L.) Moench) the fifth most important cereal crop of the world is also valued for its fodder and stover. In India, fodder sorghum is grown in 2.6 mha mainly in western UP, Haryana, Punjab, Rajasthan and Delhi and fulfils over two-third of the fodder demand. Sorghum has four desirable qualities viz., high dry matter yield, light, water and nitrogen use efficiency. Sorghum stover is valued over all other sources of fodder. Thus, sorghum is used as fodder to the domestic animals for its better performance. The projected demand for fodder in India in 2020 is expected to be 855 MT of green fodder, 526 MT of dry matter and 56 MT of concentrate feed (Dikshit and Birthal, 2010). In this perspective it is important to develop genotypes of high fodder yield and nutritive value. Cases of cyanide poisoning in animals feeding on sorghum forage have been reported in many parts of the country. HCN is absorbed into the blood stream very quickly and inhibits theanimal’s ability to deliver oxygen to tissue for cellular respiration. According to the Merck Veterinary Manual, the minimum lethal blood concentration level for HCN is approximately 3.0 μg/ml or less. It is highly desirable that the toxicity of cyanogenic plants to livestock be reduced. This is achievable by selective breeding, screeningof germplasm for low-HCN-p, mutagenesis and genetic engineering. With this background, the present investigation was contemplated among sorghum germplasm accessions to develop a reference set for cyanogenic potential (HCN-p). These accessions were also evaluated for fodder yield traits and entries with low HCN-p and high biomass were identified

    Bayesian Inference in Processing Experimental Data: Principles and Basic Applications

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    This report introduces general ideas and some basic methods of the Bayesian probability theory applied to physics measurements. Our aim is to make the reader familiar, through examples rather than rigorous formalism, with concepts such as: model comparison (including the automatic Ockham's Razor filter provided by the Bayesian approach); parametric inference; quantification of the uncertainty about the value of physical quantities, also taking into account systematic effects; role of marginalization; posterior characterization; predictive distributions; hierarchical modelling and hyperparameters; Gaussian approximation of the posterior and recovery of conventional methods, especially maximum likelihood and chi-square fits under well defined conditions; conjugate priors, transformation invariance and maximum entropy motivated priors; Monte Carlo estimates of expectation, including a short introduction to Markov Chain Monte Carlo methods.Comment: 40 pages, 2 figures, invited paper for Reports on Progress in Physic

    Observation and Assignment of Silent and Higher Order Vibrations in the Infrared Transmission of C60 Crystals

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    We report the measurement of infrared transmission of large C60 single crystals. The spectra exhibit a very rich structure with over 180 vibrational absorptions visible in the 100 - 4000 cm-1 range. Many silent modes are observed to have become weakly IR-active. We also observe a large number of higher order combination modes. The temperature (77K - 300K) and pressure (0 - 25KBar) dependencies of these modes were measured and are presented. Careful analysis of the IR spectra in conjunction with Raman scattering data showing second order modes and neutron scattering data, allow the selection of the 46 vibrational modes C60. We are able to fit *all* of the first and second order data seen in the present IR spectra and the previously published Raman data (~300 lines total), using these 46 modes and their group theory allowed second order combinations.Comment: REVTEX v3.0 in LaTeX. 12 pages. 8 Figures by request. c60lon

    Diet diversity in pastoral and agro-pastoral households in Ugandan rangeland ecosystems

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    We explore how diet diversity differs with agricultural seasons and between households within pastoral and agro-pastoral livelihood systems, using variety of foods consumed as a less complex proxy indicator of food insecurity than benchmark indicators like anthropometry and serum nutrients. The study was in the central part of the rangelands in Uganda. Seventy nine households were monitored for three seasons, and eight food groups consumed during a 24 hour diet recall period used to create a household diet diversity score (HDDS). Mean HDDS was 3.2, varied significantly with gender, age, livelihood system and season (p < .001, F = 15.04), but not with household size or household head’s education level. Agro-pastoralists exhibited lower mean diet diversity than pastoralists (p < .01, F = 7.84) and among agro-pastoralists, households headed by persons over 65 years were most vulnerable (mean HDDS 2.1). This exploratory study raises issues requiring further investigation to inform policies on nutrition security in the two communities

    Megakaryoblastic Termination of Myeloproliferative Disorders

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    Megakaryoblastic termination of myeloproliferative disorders is rare. The morphology of megakaryoblastic transformation can be subtle and is often mistaken for myeloid or lymphoid proliferations. Previously reported observations suggest a relatively poor prognosis for this category of patients, making precise diagnosis imperative. A multifaceted approach using morphology, ultrastructure, cytochemistry, and immunological membrane analysis may be helpful. We present two cases of myeloproliferative disorder with aggressive megakaryoblastic phases (myelofibrosis with agnogenic myeloid metaplasia and chronic myeloid leukemia with blast crisis). The clinical course is described and the results of the morphological, cytochemical, ultrastructural, and cytogenetic studies of both cases are presented. In addition, immunochemical studies (flow cytometry) and platelet function studies (aggregation, heta-thromboglobulin, and platelet factor IV release) were done for one of these patients
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