823 research outputs found

    Anomalous transport and phonon renormalization in a chain with transverse and longitudinal vibrations

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    We study thermal transport in a chain of coupled atoms, which can vibrate in longitudinal as well as transverse directions. The particles interact through anharmonic potentials upto cubic order. The problem is treated quantum mechanically. We first calculate the phonon frequencies self-consistently taking into account the anharmonic interactions. We show that for all the modes, frequencies must have linear dispersion with wave-vector qq for small qq irrespective of their bare dispersions. We then calculate the phonon relaxation rates Γi(q)\Gamma_i(q), where ii is the polarization index of the mode, in a self-consistent approximation based on second order perturbation diagrams. We find that the relaxation rate for the longitudinal phonon, Γx(q)q3/2\Gamma_x(q) \propto q^{3/2}, while that for the transverse phonon Γy(q)q2\Gamma_y(q) \propto q^2. The consequence of these results on the thermal conductivity κ(N)\kappa(N) of a chain of NN particles is that κ(N)N1/2\kappa(N) \propto N^{1/2}

    Continuous Functional Calculus for Quaternionic Bounded Normal Operators

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    In this article we give an approach to define continuous functional calculus for bounded quaternionic normal operators defined on a right quaternionic Hilbert space.Comment: Submitted to a journal. There was a gap in the previous version. We have corrected it and stated all the results for bounded cas

    An Effective Private Data storage and Retrieval System using Secret sharing scheme based on Secure Multi-party Computation

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    Privacy of the outsourced data is one of the major challenge.Insecurity of the network environment and untrustworthiness of the service providers are obstacles of making the database as a service.Collection and storage of personally identifiable information is a major privacy concern.On-line public databases and resources pose a significant risk to user privacy, since a malicious database owner may monitor user queries and infer useful information about the customer.The challenge in data privacy is to share data with third-party and at the same time securing the valuable information from unauthorized access and use by third party.A Private Information Retrieval(PIR) scheme allows a user to query database while hiding the identity of the data retrieved.The naive solution for confidentiality is to encrypt data before outsourcing.Query execution,key management and statistical inference are major challenges in this case.The proposed system suggests a mechanism for secure storage and retrieval of private data using the secret sharing technique.The idea is to develop a mechanism to store private information with a highly available storage provider which could be accessed from anywhere using queries while hiding the actual data values from the storage provider.The private information retrieval system is implemented using Secure Multi-party Computation(SMC) technique which is based on secret sharing. Multi-party Computation enable parties to compute some joint function over their private inputs.The query results are obtained by performing a secure computation on the shares owned by the different servers.Comment: Data Science & Engineering (ICDSE), 2014 International Conference, CUSA

    Effects of Interval Continuous and Alternate Pace Running on Cardio Respiratory Endurance

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    The purpose of the study was to find out the effects of interval continuous and alternate pace running on cardio respiratory endurance. To achieve this purpose, sixty men students in the department of physical Education and sports sciences, Annamalai university, Tamilnadu, India were selected as subjects at random. The selected subjects were divided into four equal groups of fifteen subjects each, such as interval running group, continuous running group, alternate pace running group and control group. The group I underwent interval training programme, Group II underwent continuous running programme and group III underwent alternate pace running for three days per week for twelve weeks. Group 1V acted as control group which did not participate any special training programmes apart from their regular physical education activities as per their curriculum. The age groups of the subjects were ranged from 18 to 24 years. Cardio respiratory endurance was selected as criterion variable and measured through Cooper’s 12 minutes run and walk test. All the subjects of four groups were tested on selected criterion variables at prior to and immediately training programme. The analysis of covariance revealed a significant adjusted post test mean (F = 113.63, p < 0.05). It is concluded that cardio respiratory fitness improved better in continuous method than interval and alternate pace method

    Use of Copepods as Live Feed for Larviculture of Damselfishes

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    It is well established that small-sized live feed with sufficient DHA, EPA and ARA as starter feed is the key factor for the success in larviculture of marine fishes with altricial larvae having limited yolk, which are in an undeveloped state at hatching. Copepods form a major component of the natural diet of many fish larvae and the wide range of body sizes of copepods both within and between species is extremely useful for employing the early stage nauplii and copepodites as starter feed for very small larvae with small mouth opening. Improved survival, growth and normal pigmentation have been documented in the larviculture of several marine finfishes reared with the early stage nauplii and copepodites. This is generally attributed to the levels of DHA, EPA and or arachidomic acid (ARA) in the diet and particularly to the DHA: EPA ratio in the diet. Two species of copepods viz. Euterpina acutifrons, a harpacticoid copepod and Pseudodiaptomus serricaudatus, a calanoid copepod were selected and cultured. They were employed as starter feed for the larviculture of three species of damsel fishes viz. the three spot damselfish, Dascyllus trimaculatus, the humbug damselfish, Dascyllus aruanus and the blue damselfish, Pomacentrus caeruleus. It was found that co-culturing of copepods in greenwater in the larviculture tank is the most effective method for initiating the exogenous feeding of the species studied
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