976 research outputs found

    Softly Broken A_4 Symmetry for Nearly Degenerate Neutrino Masses

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    The leptonic Higgs doublet model of neutrino masses is implemented with an A_4 discrete symmetry (the even permutation of 4 objects or equivalently the symmetry of the tetrahedron) which has 4 irreducible representations: 1, 1', 1'', and 3. The resulting spontaneous and soft breaking of A_4 provides a realistic model of charged-lepton masses as well as a nearly degenerate neutrino mass matrix. Phenomenological consequences at and below the TeV scale are discussed.Comment: 11 pages, no figur

    Reunion of Vicious Walkers: Results from Ï”\epsilon-Expansion -

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    The anomalous exponent, ηp\eta_{p}, for the decay of the reunion probability of pp vicious walkers, each of length NN, in dd (=2−ϔ)(=2-\epsilon) dimensions, is shown to come from the multiplicative renormalization constant of a pp directed polymer partition function. Using renormalization group(RG) we evaluate ηp\eta_{p} to O(Ï”2)O(\epsilon^2). The survival probability exponent is ηp/2\eta_{p}/2. For p=2p=2, our RG is exact and ηp\eta_p stops at O(Ï”)O(\epsilon). For d=2d=2, the log corrections are also determined. The number of walkers that are sure to reunite is 2 and has no Ï”\epsilon expansion.Comment: No of pages: 11, 1figure on request, Revtex3,IP/BBSR/929

    Disease Resistance Conferred by the Expression of a Gene Encoding a Synthetic Peptide in Transgenic Cotton (Gossypium hirsutum L.) Plants

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    Fertile, transgenic cotton plants expressing the synthetic antimicrobial peptide, D4E1, were produced through Agrobacterium-mediated transformation. PCR products and Southern blots confirmed integration of the D4E1 gene, while RT-PCR of cotton RNA confirmed the presence of D4E1 transcripts. In vitro assays with crude leaf protein extracts from T0 and T1 plants confirmed that D4E1 was expressed at sufficient levels to inhibit the growth of Fusarium verticillioides and Verticillium dahliae compared to extracts from negative control plants transformed with pBI-d35SΩ-uidA-nos (CGUS). Although in vitro assays did not show control of pre-germinated spores of Aspergillus flavus, bioassays with cotton seeds in situ or in planta, inoculated with a GFP-expressing A. flavus, indicated that the transgenic cotton seeds inhibited extensive colonization and spread by the fungus in cotyledons and seed coats. In planta assays with the fungal pathogen,Thielaviopsis basicola, which causes black root rot in cotton, showed typical symptoms such as black discoloration and constriction on hypocotyls, reduced branching of roots in CGUS negative control T1 seedlings, while transgenic T1 seedlings showed a significant reduction in disease symptoms and increased seedling fresh weight, demonstrating tolerance to the fungal pathogen. Significant advantages of synthetic peptides in developing transgenic crop plants that are resistant to diseases and mycotoxin-causing fungal pathogens are highlighted in this report

    New "Square Root" Model of Lepton Family Cyclic Symmetry

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    Following the newly formulated notion of form invariance of the neutrino mass matrix, a complete model of leptons is constructed. It is based on a specific unitary 3 X 3 matrix U in family space, such that U^2 is the simple discrete symmetry nu_e to -nu_e, nu_mu to nu_tau. Thus U also generates the cyclic group Z_4. The charged-lepton mass matrix is nearly diagonal while the neutrino mass matrix is of the form suitable for explaining maximal (large) mixing in atmospheric (solar) neutrino oscillations in the context of three nearly degenerate neutrino masses. Observable lepton flavor violation is predicted. Quarks may be treated in the same way as the charged leptons.Comment: 10 pages, no figur

    Is awareness of HIV enough to alter high-risk behaviour? What do HIV positive individuals have to say? A study from south India

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    This study was done to find out the awareness of HIV among HIV positive individuals before being diagnosed HIV positive. The study also provides information on whether their knowledge influenced their risk behavior if any. This is a descriptive study and data has been collected from 108 HIV positive individuals from Chennai, South India. Awareness of HIV and its mode of transmission were as high as 85%. Gender and literacy has not been a barrier to awareness. In spite of awareness of HIV/AIDS and its spread, 73% of the respondents continued risk behaviour. The respondents included men and women and their reasons for risk behavior and their manifold misconceptions have been reported. The findings call for the need to address these issues in preventive programmes aimed at HIV control

    Feasibility of community DOT providers for tuberculosis treatment in HIV infected individuals - A pilot study

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    Background: This paper summarises our experiences about the role of community DOT providers in management of TB treatment in HIV infected persons in a mainly rural population of Tamilnadu. Objectives: To evaluate the feasibility of employing Community DOT providers for the treatment of tuberculosis in HIV infected persons, to study patients’ acceptance of Community DOT providers in the closely-knit village communities and to find out the attitude and awareness of DOT Providers on TB and DOT. Method: A total of 62 tuberculosis patients (58 males and 4 females) with HIV infection attending the Government Hospital for Thoracic Medicine, Tambaram and Chennai between July 1999 and July 2002 were selected for this study. Patients were given all the doses under supervision (clinic-based DOT) during the initial intensive phase and through Community DOT providers in the continuation phase. Data was collected both from the patients and their DOT providers about their views on DOT, advantages of DOTS, drug intake, treatment adherence, problems faced by the patients and their DOT Providers in addition to the level of awareness of Community DOT Providers on tuberculosis and DOTS. Results: Regarding treatment adherence, 95% of 62 patients had taken >75% of drugs and 39% had taken 100% drugs. DOT was appreciated both by the patients and their DOTS Providers since it is cost-effective and patient-friendly. Conclusions: Community contribution to TB care even among HIV infected population is feasible, affordable and costeffective. There is a need for greater health education and training on tuberculosis and DOTS for community DOT Providers

    Investigations on Hepatoprotective Activity of Leaf Extracts of Aegle marmelos (L.) Corr. (Rutaceae)

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    The present study was carried out to screen and evaluate the hepatoprotective activity of leaf extracts of Aegle marmelos (L.) Corr. Hepatoprotective activities of ethanolic and aqueous extracts of A. marmelos were examined against carbon tetrachloride induced liver damage in mice using silymarin as control. Enzyme activities of Serum Glutamate Oxaloacetate Transaminase (SGOT), Serum Glutamate Pyruvate Transaminase (SGPT) and Alkaline Phosphatase (ALP) were analyzed. Results indicate that ethanolic and aqueous leaf extracts of A. marmelos had moderate activity over carbon tetrachloride treatment as compared to control. Results of the present investigation confirm the traditional uses of this plant as a potential hepatoprotective agent

    Light Unstable Sterile Neutrino

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    The three massless active (doublet) neutrinos may mix with two heavy and one \underline {light} sterile (singlet) neutrinos so that the induced masses and mixings among the former are able to explain the present data on atmospheric and solar neutrino oscillations. If the LSND result is also to be explained, one active neutrino mass eigenstate must mix with the light sterile neutrino. A specific model is proposed with the spontaneous and soft explicit breaking of a new global U(1)SU(1)_S symmetry so that a sterile neutrino will decay into an active antineutrino and a nearly massless pseudo-Majoron.Comment: Discussion and references adde

    Studies on Hepatoprotective Properties of Leaf Extracts of Azadirachta indica A. Juss (Meliaceae)

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    The present study was carried out to evaluate the hepatoprotective role of leaf extracts of Azadirachta indica A. Juss. Hepatoprotective activities of ethanolic and aqueous extracts of A. indica were examined against carbon tetrachloride induced liver damage in mice using silymarin as control. Enzyme activities of Serum Glutamate Oxaloacetate Transaminase (SGOT), Serum Glutamate Pyruvate Transaminase (SGPT) and Alkaline Phosphatase (ALP) were analyzed. Phytochemical leaf extracts of A. indica exhibited significant hepatoprotective activity. Ethanolic and aqueous leaf extracts of A. indica exhibited moderate activity over carbon tetrachloride treated animals. Results confirm the traditional - ethnomedicinal use of A. indica as a potential source of hepatoprotective agent

    Scaling of fluctuation for Directed polymers with random interaction

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    Using a finite size scaling form for reunion probability, we show numerically the existence of a binding-unbinding transition for Directed polymers with random interaction. The cases studied are (A1) two chains in 1+1 dimensions, (A2) two chains in 2+1 dimensions and (B) three chains in 1+1 dimensions. A similar finite size scaling form for fluctuation establishes a disorder induced transition with identical exponents for cases A2 and B. The length scale exponents in all the three cases are in agreement with previous exact renormalization group results.Comment: Revtex, 4 postscript figures available on request (email: [email protected]); To appear in J. Phys. A Letter
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