Relic density in nonuniversal gaugino mass models with SO(10) GUT symmetry

Non-universal boundary conditions in grand unified theories can lead to nonuniversal gaugino masses at the unification scale. In R-parity preserving theories the lightest supersymmetric particle is a natural candidate for the dark matter. The composition of the lightest neutralino and the identity of the next-to-lightest supersymmetric particle are studied, when nonuniversal gaugino masses come from representations of SO(10). In these cases, the thermal relic density compatible with the Wilkinson Microwave Anisotropy Probe observations is found. Relic densities are compared with the universal case. Mass spectra in the studied cases are discussed.Comment: 7 pages, 13 figures, revtex4, two-column. V2: Typos corrected and references adde

Phenomenology of non-universal gaugino masses in supersymmetric grand unified theories

Grand unified theories can lead to non-universal boundary conditions for the gaugino masses at the unification scale. We consider the implications of such non-universal boundary conditions for the composition of the lightest neutralino as well as for the upper bound on its mass in the simplest supersymmetric grand unified theory based on the SU(5) gauge group. We derive sum rules for neutralino and chargino masses in different representations of SU(5) which lead to different non-universal boundary conditions for the gaugino masses at the unification scale. We also consider the phenomenological implications of the non-universal gaugino masses arising from a grand unified theory in the context of Large Hadron Collider. In particular we investigate the detection of heavy neutral Higgs bosons $H^0, A^0$ from $H^0, A^0 \to \tilde{\chi}_2^0 \tilde{\chi}_2^0 \to 4l$, and study the possibilities of detecting the neutral Higgs bosons in cascade decays, including the decays $\tilde{\chi}_i^0 \to h^0 (H^0, A^0) \tilde{\chi}_1^0 \to b\bar{b} \tilde{\chi}_1^0$.Comment: 24 pages, uses psrfrag. Typo in Eq. (15) corrected. Added more detailed discussion about non-universality in SUSY SU(5). Parameter space and RGE loop level indicated more clearly. Added a few references. Version to be published in Phys. Rev.

Generalizations of the clustering coefficient to weighted complex networks

The recent high level of interest in weighted complex networks gives rise to a need to develop new measures and to generalize existing ones to take the weights of links into account. Here we focus on various generalizations of the clustering coefficient, which is one of the central characteristics in the complex network theory. We present a comparative study of the several suggestions introduced in the literature, and point out their advantages and limitations. The concepts are illustrated by simple examples as well as by empirical data of the world trade and weighted coauthorship networks.Comment: 4 pages, 1 table, 3 figures; revised versio

Direct and indirect orthotic management of medial compartment osteoarthritis of the knee

Osteoarthritis (OA) is a painful condition and affects approximately 80% of individuals by the age of 55 [1], with knee OA occurring two times more frequently than OA of the hand or hip [2].The condition is more prevalent in the medial compartment and restricts the daily lives of individuals due to pain and a lack of functional independence. Patients with medial compartment osteoarthritis often have a varus alignment, with the mechanical axis and load bearing passing through this compartment with a greater adduction moment leading to greater pain and progression of osteoarthritis [3]. Surgery for the condition is possible although in some cases, particularly younger patients or those not yet requiring surgery, clinical management remains a challenge. Before surgery is considered, however, conservative management is advocated, though no one treatment has been shown to be most effective, and there are few quality biomechanical or clinical studies. Of the conservative approaches the principal orthotic treatments are valgus knee braces and laterally wedged foot inlays. Studies of knee valgus bracing have consistently demonstrated an associated decreased pain and improved function [4], and greater confidence [5]. A laterally wedged foot inlay has a thicker lateral border and applies a valgus moment to the heel. It is theorised that by changing the position of the ankle and subtalar joints during weight-bearing [6] the lateral wedges may apply a valgus moment across the knee as well as the rearfoot, with the assumed reduction on load in the medial knee compartment [7]. However, there has been no study to directly compare these orthotic treatments in the same study. The aim of this research is to investigate the efficacy of valgus knee braces and laterally wedged foot inlays in reducing the varus knee moment

A Comparative study of Upper Secondary School Biology Curricula in Two Countries: Finland and Nigeria

Scientific literacy (SL) has been recognized as the main goal of science curricula documents around the world; however, comparative international curriculum research is limited, especially with Western and African countries. To fill this gap, this study aimed to compare the coverage of SL competencies with the components of knowledge, attitudes, and contexts in the upper secondary school biology curricula of Finland and Nigeria. Content analysis was used as a method and a modified version of the SL framework of the Programme for International Student Assessment 2015 (OECD, 2016) was used to analyze the curricula. The results revealed that both curricula contain the main components of SL defined in the framework, scientific knowledge being the most prominent, followed by scientific competencies. Both curricula laid less emphasis on the interpretation competency and attitudes to science component. The curricula differed in the amount of attention paid to the different areas of SL components. The Finnish curriculum focused more on content knowledge, explaining phenomena scientifically and frontiers of science and technology, while in the Nigerian curriculum procedural knowledge, evaluation and design of scientific enquiry and natural resources as context were more emphasized. The results of this study are not only important to the European and African continents but to other parts of the world for the promotion SL in schools, also the findings reinforce the call on curriculum planers and science educators to ensure equal coverage of all the dimensions of SL in the school science curriculum if the next generation of the world is to be scientifically literate.Peer reviewe

Phylogenetic analyses suggest multiple changes of substrate specificity within the Glycosyl hydrolase 20 family

<p>Abstract</p> <p>Background</p> <p>Beta-N-acetylhexosaminidases belonging to the glycosyl hydrolase 20 (GH20) family are involved in the removal of terminal β-glycosidacally linked N-acetylhexosamine residues. These enzymes, widely distributed in microorganisms, animals and plants, are involved in many important physiological and pathological processes, such as cell structural integrity, energy storage, pathogen defence, viral penetration, cellular signalling, fertilization, development of carcinomas, inflammatory events and lysosomal storage diseases. Nevertheless, only limited analyses of phylogenetic relationships between GH20 genes have been performed until now.</p> <p>Results</p> <p>Careful phylogenetic analyses of 233 inferred protein sequences from eukaryotes and prokaryotes reveal a complex history for the GH20 family. In bacteria, multiple gene duplications and lineage specific gene loss (and/or horizontal gene transfer) are required to explain the observed taxonomic distribution. The last common ancestor of extant eukaryotes is likely to have possessed at least one GH20 family member. At least one gene duplication before the divergence of animals, plants and fungi as well as other lineage specific duplication events have given rise to multiple paralogous subfamilies in eukaryotes. Phylogenetic analyses also suggest that a second, divergent subfamily of GH20 family genes present in animals derive from an independent prokaryotic source. Our data suggest multiple convergent changes of functional roles of GH20 family members in eukaryotes.</p> <p>Conclusion</p> <p>This study represents the first detailed evolutionary analysis of the glycosyl hydrolase GH20 family. Mapping of data concerning physiological function of GH20 family members onto the phylogenetic tree reveals that apparently convergent and highly lineage specific changes in substrate specificity have occurred in multiple GH20 subfamilies.</p

Edge magnetoplasmons and the optical excitations in graphene disks

We discuss the edge magnetoplasmon properties in highly doped graphene disks, and the corresponding optical excitations. Edge magnetoplasmons with nonzero angular momentum (l not equal 0) have two branches corresponding to different edge current rotations with respect to the magnetic field. The resonance energies of one branch are blueshifted and the other redshifted relative to energies at B = 0, with the energy differences linearly proportional to the magnetic field. Recently, the l = 1 dipole mode has been investigated by two experiments using optical transmission spectroscopy [Crassee et al., Nano Lett. 12, 2470 (2012); Yan et al., ibid. 12, 3766 (2012)], and classical cyclotron resonances were found in highly doped graphene samples. These are determined by graphene magneto-optical conductivities, which behave like a conventional two-dimensional electron system in the high doping limit

Edge plasmons in graphene nanostructures

Plasmon modes in graphene are influenced by the unusual dispersion relation of the material. For bulk plasmons this results in a n(1/4) dependence of the plasma frequency on the charge density, as opposed to the n(1/2) dependence in two-dimensional electron gas (2DEG); yet, bulk plasmon dispersion in graphene follows a similar q(1/2) behavior as for other two-dimensional materials. In this work we consider finite graphene nanostructures, semi-infinite sheets, and circular disks and study edge plasmons that are confined to the boundaries of the structures. We find that, for abrupt edges, graphene edge plasmons behave analogously to those in 2DEGs, but, for gradual edge profiles, important distinctions arise. In particular, we show that for a linear edge profile, graphene supports fewer edge modes than a 2DEG at a given q, and the edge monopole plasmon dispersion in graphene follows a q(1/4) law in contrast to the q(0) behavior seen in 2DEGs. RAMOWITZ M, 196

Non-equilibrium Plasmons in a Quantum Wire Single Electron Transistor

We analyze a single electron transistor composed of two semi-infinite one dimensional quantum wires and a relatively short segment between them. We describe each wire section by a Luttinger model, and treat tunneling events in the sequential approximation when the system's dynamics can be described by a master equation. We show that the steady state occupation probabilities in the strongly interacting regime depend only on the energies of the states and follow a universal form that depends on the source-drain voltage and the interaction strength.Comment: 4 pages, 3 figures. To appear in the Phys. Rev. Let

Shot Noise and Full Counting Statistics from Non-equilibrium Plasmons in Luttinger-Liquid Junctions

We consider a quantum wire double junction system with each wire segment described by a spinless Luttinger model, and study theoretically shot noise in this system in the sequential tunneling regime. We find that the non-equilibrium plasmonic excitations in the central wire segment give rise to qualitatively different behavior compared to the case with equilibrium plasmons. In particular, shot noise is greatly enhanced by them, and exceeds the Poisson limit. We show that the enhancement can be explained by the emergence of several current-carrying processes, and that the effect disappears if the channels effectively collapse to one due to, {\em e.g.}, fast plasmon relaxation processes.Comment: 9 pages; IOP Journal style; several changes in the tex