1,427 research outputs found

    Lattice study on two-color QCD with six flavors of dynamical quarks

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    We study the dynamics of SU(2) gauge theory with NF=6 Dirac fermions by means of lattice simulation to investigate if they are appropriate to realization of electroweak symmetry breaking. The discrete analogue of beta function for the running coupling constant defined under the Schroedinger functional boundary condition are computed on the lattices up to linear size of L/a=24 and preclude the existence of infrared fixed point below 7.6. Gluonic observables such as heavy quark potential, string tension, Polyakov loop suggest that the target system is in the confining phase even in the massless quark limit.Comment: 7 pages, 9 figures, Proceedings of The 30th International Symposium on Lattice Field Theory, June 24-29, 2012, Cairns, Australi

    Anisotropic magnetic fluctuations in the ferromagnetic superconductor UCoGe studied by angle-resolved ^{59}Co NMR

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    We have carried out direction-dependent ^{59}Co NMR experiments on a single crystal sample of the ferromagnetic superconductor UCoGe in order to study the magnetic properties in the normal state. The Knight shift and nuclear spin-lattice relaxation rate measurements provide microscopic evidence that both static and dynamic susceptibilities are ferromagnetic with strong Ising anisotropy. We discuss that superconductivity induced by these magnetic fluctuations prefers spin-triplet pairing state.Comment: 4 pages, 4 figure

    Status, Experience and Challenges for Promoting Gifted and Talented Students Education Provision in Ilala, Dar es Salaam

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    It is widely known that learners vary in achievement, ability as well as talent. Interest in gifted and talented learners has a long history. However, in most developing countries, education systems are yet to create a suitable environment to develop and nurture the special talents that some learners have, sometimes due to lack of a proper understanding of the variety of talents available and also lack of resources to support them. Exploring the status, experience, and challenges that the gifted and talented learners of Tanzania experience is not an easy task; considering that the so called gifted and talented are not prioritized in our education system. This study aimed at exploring the criteria for identifying and selecting gifted and talented students in secondary schools, the way they are groomed and challenges they face together with the way forward in addressing those problems in Ilala municipality of Dar es Salaam City. Two selected schools were sampled through purposive sampling and the interview and questionnaire tools were applied in collecting the data from teachers, students, and parents. Quantitative data collected were analyzed using descriptive statistical techniques and thematic analysis was used for analyzing qualitative data. The findings indicated that, learners and teachers lack government support on identification of gifted and talented children. Teaching and learning materials are not sufficient for the students to learn effectively and too few skilled teachers are available to instruct and support talented students. The number of skilled teachers is small compared to the needs of the system and the system does not provide opportunities for the students to display their talents. The study recommends that further studies should be conducted on how to create opportunities, development, and motivation of key talented children education provision for this category of learners. The new Education and Training Policy needs to be reviewed and show plans to accommodate talent and gifted education development in our schools

    In-the-Gap SU UMa-Type Dwarf Nova, Var73 Dra with a Supercycle of about 60 Days

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    An intensive photometric-observation campaign of the recently discovered SU UMa-type dwarf nova, Var73 Dra was conducted from 2002 August to 2003 February. We caught three superoutbursts in 2002 October, December and 2003 February. The recurrence cycle of the superoutburst (supercycle) is indicated to be \sim60 d, the shortest among the values known so far in SU UMa stars and close to those of ER UMa stars. The superhump periods measured during the first two superoutbursts were 0.104885(93) d, and 0.10623(16) d, respectively. A 0.10424(3)-d periodicity was detected in quiescence. The change rate of the superhump period during the second superoutburst was 1.7×1031.7\times10^{-3}, which is an order of magnitude larger than the largest value ever known. Outburst activity has changed from a phase of frequent normal outbursts and infrequent superoutbursts in 2001 to a phase of infrequent normal outbursts and frequent superoutbursts in 2002. Our observations are negative to an idea that this star is an related object to ER UMa stars in terms of the duty cycle of the superoutburst and the recurrence cycle of the normal outburst. However, to trace the superhump evolution throughout a superoutburst, and from quiescence more effectively, may give a fruitful result on this matter.Comment: 9 pages, 8 figures, submitted to A&

    Superconductivity induced by longitudinal ferromagnetic fluctuations in UCoGe

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    From detailed angle-resolved NMR and Meissner measurements on a ferromagnetic (FM) superconductor UCoGe (T_Curie ~ 2.5 K and T_SC ~ 0.6 K), we show that superconductivity in UCoGe is tightly coupled with longitudinal FM spin fluctuations along the c axis. We found that magnetic fields along the c axis (H || c) strongly suppress the FM fluctuations and that the superconductivity is observed in the limited magnetic field region where the longitudinal FM spin fluctuations are active. These results combined with model calculations strongly suggest that the longitudinal FM spin fluctuations tuned by H || c induce the unique spin-triplet superconductivity in UCoGe. This is the first clear example that FM fluctuations are intimately related with superconductivity.Comment: 4 pages, 5 figures, to appear in PR
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