Holographic Superconductors in 3+1 dimensions away from the probe limit

We study holographic superconductors in 3+1 dimensions away from the probe limit, i.e. taking back-reaction of the space-time into account. We consider the case of pure Einstein- and Gauss-Bonnet gravity, respectively. Similar to the probe limit we observe that the critical temperature at which condensation sets in decreases with increasing Gauss-Bonnet coupling. The decrease is however stronger when taking back-reaction of the space-time into account. We observe that the critical temperature becomes very small, but stays positive for all values of the Gauss-Bonnet coupling no matter how strong the back-reaction of the space-time is.Comment: 10 pages including 5 figures; references adde

Master of Social Work

thesisA need to do an exploratory study of the Navajo traditional child rearing practices grew out of a discussion between key personnel and five Navajo graduate students at the University of Utah Graduate School of Social Work. The result led to a study of traditional Navajo child rearing practices. The study population included 56 (100%) elderly Navajo men and women over the age 60, who had substantial know-ledge of child rearing based upon their own experiences. The information gathered were done in the Navajo language. A minimum of 25 hours of interviewing time, with an average of approximately two hours were spent with each informant who were selected across the Navajo Reservation. This study explored the traditional Navajo child rearing patterns among the Navajos from prenatal period to age three. The following factors were identified as the basic elements in what may be presumed to be typical child rearing patterns. The four phases identified were: (1) Pre-birth, (2) Pre-cradle Board, (3) Cradle Board, and (4) Post-cradle Board. The study revealed that there were evidences of typical Navajo child rearing practices of growth and development which were organized in a chronological life experience framework in the Navajo cultural context of personality development. It was also found that values, beliefs, cultural practices and the extended family system played an important role in each of the above mentioned phases of the traditional Navajo child rearing patterns

Mass of Prunus africana stem barks on Tchabal mbabo and Tchabal Gang Daba Mountain Forests, Cameroon

Prunus africana is a species of the Rosaceae family, known under its common name as pygeum or African cherry. The bark is the major source of an extract used to treat benign prostatic hyperplasia, an increasingly common health problem in older men in the western world. A study which aimed to produce a formula for establishing the mass of the bark of Prunus africana specimens was carried out in May 2011 on Tchabal Mbabo and Tchabal Gang Daba mountain forests, in the Adamaoua region of Cameroon. The diameter at breast height (DBH), the height of the tree and the thickness of the stem bark of each pygeum tree were recorded in order to establish the cubic volume of each specimen. This data was used to calculate the relationship between the diameter and the volume of the bark. Samples of bark were collected in order to establish the relationship between the volume of the bark and its mass (measure mass per cubic metre). A total of 105 pygeum trees were sampled, including 50 trees in Gang Daba considered as an un-exploited production site and 55 trees in Mbabo referred to an exploited production site. The best equation which links the volume (Vb) of fresh barks to the diameter (D) of each pygeum tree is Vb=a/(1+b*exp(-cD)) with a = 1.79588278896E-001, b =  5.29124992540E+002, c = 1.45488065368E-001. The average thickness of the bark is 13.01 ± 4.8 mm. This value is comprised between that of unexploited (16.99 ± 3.7 mm) and exploited (9.40 ± 2.07 mm) pygeum trees. Considering that for all trees above 30 cm DBH, only two quarters of the bark are taken from the main stem up to the first branch, the average sustainable mass of pygeum tree in Adamaoua region will be about 69.3 kg of fresh bark per tree. This value is comprised between that of unexploited (80 kg) and exploited (60 kg) pygeum trees in Ganga Daba and Mbabo respectively.Key words: Threatened species, Prunus africana, pygeum, Tchabal  mountain forests, Bitterlich’s Relascope, cubic tariff, CITES

Inflating branes inside abelian strings

We study a 6-dimensional brane world model with an abelian string residing in the two extra dimensions. We study both static as well as inflating branes and find analytic solutions for the case of trivial matter fields in the bulk. Next to singular space-times, we also find solutions which are regular including cigar-like universes as well as solutions with periodic metric functions. These latter solutions arise if in a singular space-time a static brane is replaced by an inflating brane. We determine the pattern of generic solutions for positive, negative and zero bulk cosmological constant.Comment: 14 Latex pages, 11 postscript figures; references added, discussion extended; reference adde

Gravitating Semilocal strings

We discuss the properties of semilocal strings minimally coupled to gravity. Semilocal strings are solutions of the bosonic sector of the Standard Model in the limit $\sin^2\theta_W=1$ (where $\theta_W$ is the Weinberg angle) and correspond to embedded Abelian-Higgs strings for a particular choice of the scalar doublet. We focus on the limit where the gauge boson mass is equal to the Higgs boson mass such that the solutions fulfill the Bogomolnyi-Prasad-Sommerfield (BPS) bound.Comment: Contribution to the Proceedings of the Spanish Relativity Meeting (ERE) 2009, Bilbao, Spai

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

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

Glueball condensates as holographic duals of supersymmetric Q-balls and boson stars

We study non-spinning Q-balls and boson stars in 4-dimensional Anti-de Sitter (AdS) space-time. We use an exponential scalar field potential that appears in gauge-mediated supersymmetry (SUSY) breaking in the minimal supersymmetric extension of the Standard Model (MSSM). We investigate the dependence of the charge and mass of these non-topological solitons on the negative cosmological constant, the frequency that appears in the periodic time-dependence as well as on the ratio between the SUSY breaking scale and the Planck mass. Next to fundamental solutions without nodes in the scalar field function we also construct radially excited solutions. In the second part of the paper we put the emphasis on the holographic interpretation of these solutions in terms of Bose-Einstein condensates of scalar glueballs that are described by a strongly coupled Quantum Field Theory (QFT) on the boundary of global AdS.Comment: 17 pages including 11 figures; v2: 19 pages including 13 figures, references added, figures adde

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

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

Stability of Gauss-Bonnet black holes in Anti-de-Sitter space-time against scalar field condensation

We study the stability of static, hyperbolic Gauss-Bonnet black holes in (4+1)-dimensional Anti-de-Sitter (AdS) space-time against the formation of scalar hair. Close to extremality the black holes possess a near-horizon topology of AdS_2 x H^3 such that within a certain range of the scalar field mass one would expect that they become unstable to the condensation of an uncharged scalar field. We confirm this numerically and observe that there exists a family of hairy black hole solutions labelled by the number of nodes of the scalar field function. We construct explicit examples of solutions with a scalar field that possesses zero nodes, one node and two nodes, respectively, and show that the solutions with nodes persist in the limit of Einstein gravity, i.e. for vanishing Gauss-Bonnet coupling. We observe that the interval of the mass for which scalar field condensation appears decreases with increasing Gauss-Bonnet coupling and/or with increasing node number.Comment: 14 pages including 7 figure