Antimicrobial Activity of Zingiber Officinale and Allium Sativum on some Drug Resistant Bacterial Isolates

Ginger and garlic are very important and useful spices and are used as therapeutic agent against many pathological infections. Increasing multi-drug resistance of pathogens forces researchers to find alternative compounds for treatment of infectious diseases. In this study, the antimicrobial potency of ginger and garlic were investigated against four clinical bacterial isolates. Three types of ginger and garlic extracts (aqueous extract, methanol extract and ethanol extract) were assayed separately against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Salmonella typhi. The antibacterial activity was determined by well diffusion method. The minimum inhibitory concentration (MIC) of different bacterial species varied from 1.5625mg/ml to 5.0mg/ml with ginger extracts having the lowest and garlic extracts having the highest respectively. All tested bacterial were most susceptible to the garlic aqueous extract and showed poor susceptibility to the ginger aqueous extract. However, ginger extracts from the mean zone of inhibition have higher antimicrobial activity when compared to garlic extracts with exception to garlic aqueous extract. This study encourages the use of spices especially ginger and garlic as alternative or supplementary medicine to reduce the burden of high cost, side effects and progressively increasing drug resistance of pathogens

Flavour structure and proton decay in 6D orbifold GUTs

We study proton decay in a supersymmetric {\sf SO(10)} gauge theory in six dimensions compactified on an orbifold. The dimension-5 proton decay operators are forbidden by R-symmetry, whereas the dimension-6 operators are enhanced due to the presence of KK towers. Three sequential quark-lepton families are localised at the three orbifold fixed points, where {\sf SO(10)} is broken to its three GUT subgroups. The physical quarks and leptons are mixtures of these brane states and additional bulk zero modes. This leads to a characteristic pattern of branching ratios in proton decay, in particular the suppression of the p\to \m^+K^0 mode.Comment: 20 pages, 1 figur

Spontaneous CP Violation in a SUSY Model with a complex CKM

It is pointed out that the recent measurement of the angle $\gamma$ of the unitarity triangle, providing irrefutable evidence for a complex Cabibbo-Kobayashi-Maskawa (CKM) matrix, presents a great challenge for supersymmetric models with spontaneous CP violation. We construct a new minimal extension of the minimal supersymmetric standard model (MSSM), with spontaneous CP breaking, which leads to a complex CKM matrix, thus conforming to present experimental data. This is achieved through the introduction of two singlet chiral superfields and a vector-like quark chiral superfield which mixes with the standard quarks. A $Z_3$ symmetry is introduced in order to have a potential solution to the strong CP problem.Comment: 12 pages. Uses the elsart.cls LaTeX class. Minor corrections and references adde

SU(5) Unified Theories from Intersecting Branes

We discuss the first string theory examples of three generation non-supersymmetric SU(5) and {\em flipped} SU(5) GUTS, which break to the Standard model at low energy, without extra matter and/or gauge group factors. Our GUT examples are based on IIA $Z_3$ orientifolds with D6-branes intersecting at non-trivial angles. These theories necessarily satisfy RR tadpoles and are free of NSNS tadpoles as the complex structure moduli are frozen (even though a dilaton tadpole remains) to discrete values. We identify appropriately the bifundamental Higgses responsible for electroweak symmetry breaking. In this way, the neutrino see-saw mechanism get nicely realized in these constructions. Moreover, as baryon number is not a gauged symmetry gauge mediated dimension six operators do contribute to proton decay; however proton lifetime may be safely enhanced by appropriately choosing a high GUT scale. An accompanying natural doublet-triplet splitting guarantees the suppression of scalar mediated proton decay modes and the stability of triplet scalar masses against higher dimensional non-renormalizable operators.Comment: 26 pages, 5 figures; no changes, one comment added in the introductio

Kernel Spectral Clustering and applications

In this chapter we review the main literature related to kernel spectral clustering (KSC), an approach to clustering cast within a kernel-based optimization setting. KSC represents a least-squares support vector machine based formulation of spectral clustering described by a weighted kernel PCA objective. Just as in the classifier case, the binary clustering model is expressed by a hyperplane in a high dimensional space induced by a kernel. In addition, the multi-way clustering can be obtained by combining a set of binary decision functions via an Error Correcting Output Codes (ECOC) encoding scheme. Because of its model-based nature, the KSC method encompasses three main steps: training, validation, testing. In the validation stage model selection is performed to obtain tuning parameters, like the number of clusters present in the data. This is a major advantage compared to classical spectral clustering where the determination of the clustering parameters is unclear and relies on heuristics. Once a KSC model is trained on a small subset of the entire data, it is able to generalize well to unseen test points. Beyond the basic formulation, sparse KSC algorithms based on the Incomplete Cholesky Decomposition (ICD) and $L_0$, $L_1, L_0 + L_1$, Group Lasso regularization are reviewed. In that respect, we show how it is possible to handle large scale data. Also, two possible ways to perform hierarchical clustering and a soft clustering method are presented. Finally, real-world applications such as image segmentation, power load time-series clustering, document clustering and big data learning are considered.Comment: chapter contribution to the book "Unsupervised Learning Algorithms

Spin injection into a ballistic semiconductor microstructure

A theory of spin injection across a ballistic ferromagnet-semiconductor-ferromagnet junction is developed for the Boltzmann regime. Spin injection coefficient $\gamma$ is suppressed by the Sharvin resistance of the semiconductor $r_N^*=(h/e^2)(\pi^2/S_N)$, where $S_N$ is the Fermi-surface cross-section. It competes with the diffusion resistances of the ferromagnets $r_F$, and $\gamma\sim r_F/r_N^*\ll 1$ in the absence of contact barriers. Efficient spin injection can be ensured by contact barriers. Explicit formulae for the junction resistance and the spin-valve effect are presented.Comment: 5 pages, 2 column REVTeX. Explicit prescription relating the results of the ballistic and diffusive theories of spin injection is added. To this end, some notations are changed. Three references added, typos correcte

Yukawa coupling unification and non-universal gaugino mediation of supersymmetry breaking

The requirement of Yukawa coupling unification highly constrains the SUSY parameter space. In several SUSY breaking scenarios it is hard to reconcile Yukawa coupling unification with experimental constraints from B(b->s gamma) and the muon anomalous magnetic moment a_mu. We show that b-tau or even t-b-tau Yukawa unification can be satisfied simultaneously with b->s gamma and a_mu in the non-universal gaugino mediation scenario. Non-universal gaugino masses naturally appear in higher dimensional grand unified models in which gauge symmetry is broken by orbifold compactification. Relations between SUSY contributions to fermion masses, b->s gamma and a_mu which are typical for models with universal gaugino masses are relaxed. Consequently, these phenomenological constraints can be satisfied simultaneously with a relatively light SUSY spectrum, compared to models with universal gaugino masses.Comment: 20 pages, 8 figures. References added. A copy of the paper with better resolution figures can be found at http://www.hep.fsu.edu/~balazs/Physics/Papers/2003