6,461 research outputs found

    The effect of dark strings on semilocal strings

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    Dark strings have recently been suggested to exist in new models of dark matter that explain the excessive electronic production in the galaxy. We study the interaction of these dark strings with semilocal strings which are solutions of the bosonic sector of the Standard Model in the limit sin2θw=1\sin^2\theta_{\rm w}=1, where θw\theta_{\rm w} is the Weinberg angle. While embedded Abelian-Higgs strings exist for generic values of the coupling constants, we show that semilocal solutions with non-vanishing condensate inside the string core exist only above a critical value of the Higgs to gauge boson mass ratio when interacting with dark strings. Above this critical value, which is greater than unity, the energy per unit length of the semilocal-dark string solutions is always smaller than that of the embedded Abelian-Higgs-dark string solutions and we show that Abelian-Higgs-dark strings become unstable above this critical value. Different from the non-interacting case, we would thus expect semilocal strings to be stable for values of the Higgs to gauge boson mass ratio larger than unity. Moreover, the one-parameter family of solutions present in the non-interacting case ceases to exist when semilocal strings interact with dark strings.Comment: 16 pages including 6 figures; stability analysis adde

    Remarks on the interaction between Born-Infeld solitons

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    We consider the Abelian Higgs model as well as the SU(2) Georgi-Glashow model in which the gauge field action is replaced by a non linear Born-Infeld action. We study soliton solutions arising in these models, namely the vortex and monopole solutions, respectively. We construct formulas which provide good approximations for the mass of the Born-Infeld deformed solitons using only the data of the undeformed solutions. The results obtained indicate that in the self-dual limit, the Born-Infeld interaction leads to bound vortices, while for monopoles it gives rise to repulsion.Comment: 11 Revtex pages; some typos corrected, formular adde

    Analisis Lama Waktu Pelayanan Laboratorium di Rumah Sakit Umum Daerah Pasaman Barat

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    Hospital laboratory services is one of the activities in hospitals that support quality health services. One indicator of the success of health services in the field of clinical pathology laboratory services is the waiting time for laboratory services. The standard set for laboratory service outcome waiting time is ≤ 140 minutes for blood chemistry and routine blood. This research analyzed the service time of outpatient laboratory that conducted hematology and clinical chemistry examination in the laboratory of Pasaman Barat Hospital. This research is a type of descriptive analytic research that is quantitative and supported by qualitative using cross sectional approach. The result of the research showed that laboratory service time at RSUD Pasaman Barat fulfilled the standard (≤ 140 minutes) for hematology examination 33.94 minutes, clinical chemistry 83.92 minutes, hematology and clinical chemistry 98 minutes. Based on the results of this study, the stages that contribute to the length of time laboratory services for hematological examination lies in the pre analytical stage, for clinical chemistry examination is located at the analytical stage, as well as for hematology and clinical chemistry examination lies in the analytic stage as well as the factors that affect the length of time laboratory services are human resources that is in the ability of officers and infrastructure facilitie

    Geodesic motion in the space-time of cosmic strings interacting via magnetic fields

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    We study the geodesic motion of test particles in the space-time of two Abelian-Higgs strings interacting via their magnetic fields. These bound states of cosmic strings constitute a field theoretical realization of p-q-strings which are predicted by inflationary models rooted in String Theory, e.g. brane inflation. In contrast to previously studied models describing p-q-strings our model possesses a Bogomolnyi-Prasad-Sommerfield (BPS) limit. If cosmic strings exist it would be exciting to detect them by direct observation. We propose that this can be done by the observation of test particle motion in the space-time of these objects. In order to be able to make predictions we have to solve the field equations describing the configuration as well as the geodesic equation numerically. The geodesics can then be classified according to the test particle's energy, angular momentum and momentum along the string axis. We find that the interaction of two Abelian-Higgs strings can lead to the existence of bound orbits that would be absent without the interaction. We also discuss the minimal and maximal radius of orbits and comment on possible applications in the context of gravitational wave emission.Comment: v1: 22 pages including 17 figures; v2: new figure added, section on observables added; acccepted for publication in Phys. Rev.

    Gravitating superconducting strings with timelike or spacelike currents

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    We construct gravitating superconducting string solutions of the U(1)_{local} x U(1)_{global} model solving the coupled system of Einstein and matter field equations numerically. We study the properties of these solutions in dependence on the ratio between the symmetry breaking scale and the Planck mass. Using the macroscopic stability conditions formulated by Carter, we observe that the coupling to gravity allows for a new stable region that is not present in the flat space-time limit. We match the asymptotic metric to the Kasner metric and show that the relations between the Kasner coefficients and the energy per unit length and tension suggested previously are well fulfilled for symmetry breaking scale much smaller than the Planck mass. We also study the solutions to the geodesic equation in this space-time. While geodesics in the exterior space-time of standard cosmic strings are just straight lines, test particles experience a force in a general Kasner space-time and as such bound orbits are possible.Comment: 16 pages including 14 figure

    The Impact of Government Assist in Developing Hatchery of Tilapia (Oreochromis Niloticus) Member is Sejahtera Group in Side of the Pond in Silau Malaha Village Siantar District Simalungun Regency North Sumatera Province

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    This research was conducted on 3-14 may 2015. The purpose of this research is to know the development the fish hatchery. Start from the wide of pull the number of production development, the income, and extension of region trade for Sejahtera Group. This research was used survey method. The determination responded was taken with a simple random sampling the population in research was the member of Sejahtera Group who has their own job as hatchery. The number of member is 22 persons. Remembering the characteristic the job of population is relative homogeny so in taking in responden was enough 50% for is hatchery.The result of this research showed that the fish hatchery was done by the member of Sejahtera Group has a good development after accepting the assist from government. The wide of pool before accepting the assist in 2011 was around 909 m² but after get the assist in 2014 the wide of pool becomes 2,672 m², the number of seeds of production which gotten before getting the assist was around 68,091 seeds per year after got the assist from government the number of production increased become 200,454 per year. The income fish hatchery before get the assist 15.403.773,- and after got the assist from government the income is increased to be 47.378.745,- the wide of trade region before got the assist just to region they were Siantar, Balige, Parapat, Porsea, Haranggaol, and Salbe

    Deformed vortices in (4+1)-dimensional Einstein-Yang-Mills theory

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    We study vortex-type solutions in a (4+1)-dimensional Einstein-Yang-Mills-SU(2) model. Assuming all fields to be independent on the extra coordinate, these solutions correspond in a four dimensional picture to axially symmetric multimonopoles, respectively monopole-antimonopole solutions. By boosting the five dimensional purely magnetic solutions we find new configurations which in four dimensions represents rotating regular nonabelian solutions with an additional electric charge.Comment: 11 pages, including 5 eps files; reference added, discussion extended; typos correcte

    Spherically symmetric Yang-Mills solutions in a (4+n)- dimensional space-time

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    We consider the Einstein-Yang-Mills Lagrangian in a (4+n)-dimensional space-time. Assuming the matter and metric fields to be independent of the n extra coordinates, a spherical symmetric Ansatz for the fields leads to a set of coupled ordinary differential equations. We find that for n > 1 only solutions with either one non-zero Higgs field or with all Higgs fields constant exist. We construct the analytic solutions which fulfill this conditions for arbitrary n, namely the Einstein-Maxwell-dilaton solutions. We also present generic solutions of the effective 4-dimensional Einstein-Yang-Mills-Higgs-dilaton model, which possesses n Higgs triplets coupled in a specific way to n independent dilaton fields. These solutions are the abelian Einstein-Maxwell- dilaton solutions and analytic non-abelian solutions, which have diverging Higgs fields. In addition, we construct numerically asymptotically flat and finite energy solutions for n=2.Comment: 15 Latex pages, 4 eps figures; v2: discussion of results revisite

    Stochastic homogenization of the laser intensity to improve the irradiation uniformity of capsules directly driven by thousands laser beams

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    Illumination uniformity of a spherical capsule directly driven by laser beams has been assessed numerically. Laser facilities characterized by ND = 12, 20, 24, 32, 48 and 60 directions of irradiation with associated a single laser beam or a bundle of NB laser beams have been considered. The laser beam intensity profile is assumed super-Gaussian and the calculations take into account beam imperfections as power imbalance and pointing errors. The optimum laser intensity profile, which minimizes the root-mean-square deviation of the capsule illumination, depends on the values of the beam imperfections. Assuming that the NB beams are statistically independents is found that they provide a stochastic homogenization of the laser intensity associated to the whole bundle, reducing the errors associated to the whole bundle by the factor  , which in turn improves the illumination uniformity of the capsule. Moreover, it is found that the uniformity of the irradiation is almost the same for all facilities and only depends on the total number of laser beams Ntot = ND × NB

    Deformed black strings in 5-dimensional Einstein-Yang-Mills theory

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    We construct the first examples of deformed non-abelian black strings in a 5-dimensional Einstein-Yang-Mills model. Assuming all fields to be independent of the extra coordinate, we construct deformed black strings, which in the 4-dimensional picture correspond to axially symmetric non-abelian black holes in gravity-dilaton theory. These solutions thus have deformed S^2 x R horizon topology. We study fundamental properties of the black strings and find that for all choices of the gravitational coupling two branches of solutions exist. The limiting behaviour of the second branch of solutions however depends strongly on the choice of the gravitational coupling.Comment: 8 Revtex pages; 4 eps figures; references adde
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