Novel Spin and Statistical Properties of Nonabelian Vortices

We study the statistics of vortices which appear in (2+1)--dimensional spontaneously broken gauge theories, where a compact group G breaks to a finite nonabelian subgroup H. Two simple models are presented. In the first, a quantum state which is symmetric under the interchange of a pair of indistinguishable vortices can be transformed into an antisymmetric state after the passage through the system of a third vortex with an appropriate $H$-flux element. Further, there exist states containing two indistinguishable spinless vortices which obey Fermi statistics. These results generalize to loops of nonabelian cosmic string in 3+1 dimensions. In the second model, fractional analogues of the above behaviors occur. Also, composites of vortices in this theory may possess fractional ``Cheshire spin'' which can be changed by passing an additional vortex through the system.Comment: 11 pages, UICHEP-TH/92-15; FERMILAB-PUB-92/233-T; SLAC-PUB-588

Plastic deformation and twinning mechanisms in magnesian calcites: a non-equilibrium computer simulation study

Deformation twinning provides a mechanism for energy dissipation in crystalline structures, with important implications on the mechanical response of carbonate biogenic materials. Carbonate crystals can incorporate magnesium, e.g. in the sea, modifying their elastic response significantly. We present a full atom computational investigation of the dependence of the twinning response of calcite with magnesium content, covering compositions compatible with three main structures, calcite, dolomite and magnesite. We find, in agreement with experiments that the incorporation of magnesium disfavors twinning as a dissipation mechanism in ordered structures (dolomite, magnesite), however the response is strongly dependent on the arrangement of the magnesium ions in the crystal structure. We show that structures with a high content of magnesium (>33%) in a disordered arrangement, lead to plastic response before twinning or fracturing. We demonstrate that the position of the magnesium ions plays a key role in the determination of the crystal deformation mode. This observation is correlated with the formation of percolation clusters of magnesium in magnesian calcites

Reference pricing with endogenous generic entry

In this paper we study the effect of reference pricing on pharmaceutical prices and ex-penditures when generic entry is endogenously determined. We develop a Salop-type model where a brand-name producer competes with generic producers in terms of prices. In the market there are two types of consumers: (i) brand biased consumers who choose between brand-name and generic drugs, and (ii) brand neutral consumers who choose between the different generic drugs. We find that, for a given number of firms, reference pricing leads to lower prices of all products and higher brand-name market shares compared with a reimbursement scheme based on simple coinsurance. Thus, in a free entry equilibrium, the number of generics is lower under reference pricing than under coinsurance, implying that the net effects of reference pricing on prices and expenditures are ambiguous. Allowing for price cap regulation, we show that the negative effect on generic entry can be reversed, and that reference pricing is more likely to result in cost savings than under free pricing. Our results shed light on the mixed empirical evidence on the effects of reference pricing on generic entry.COMPETEQRENFEDER,Fundação para a Ciência e a Tecnologia (FCT

Spinning Particles, Braid Groups and Solitons

We develop general techniques for computing the fundamental group of the configuration space of $n$ identical particles, possessing a generic internal structure, moving on a manifold $M$. This group generalizes the $n$-string braid group of $M$ which is the relevant object for structureless particles. In particular, we compute these generalized braid groups for particles with an internal spin degree of freedom on an arbitrary $M$. A study of their unitary representations allows us to determine the available spectrum of spin and statistics on $M$ in a certain class of quantum theories. One interesting result is that half-integral spin quantizations are obtained on certain manifolds having an obstruction to an ordinary spin structure. We also compare our results to corresponding ones for topological solitons in $O(d+1)$-invariant nonlinear sigma models in $(d+1)$-dimensions, generalizing recent studies in two spatial dimensions. Finally, we prove that there exists a general scalar quantum theory yielding half-integral spin for particles (or $O(d+1)$ solitons) on a closed, orientable manifold $M$ if and only if $M$ possesses a ${\rm spin}_c$ structure.Comment: harvmac, 34 pages, HUTP-93/A037; UICHEP-TH/93-18; BUHEP-93-2

Nonabelian Vortices on Surfaces and Their Statistics

We discuss the physics of topological vortices moving on an arbitrary surface M in a Yang-Mills-Higgs theory in which the gauge group G breaks to a finite subgroup H. We concentrate on the case where M is compact and/or nonorientable. Interesting new features arise which have no analog on the plane. The consequences for the quantum statistics of vortices are discussed, particularly when H is nonabelian.Comment: 27 pages, 6 figures, requires harvma

Extracting individual contributions from their mixture: a blind source separation approach, with examples from space and laboratory plasmas

Multipoint or multichannel observations in plasmas can frequently be modelled as an instantaneous mixture of contributions (waves, emissions, ...) of different origins. Recovering the individual sources from their mixture then becomes one of the key objectives. However, unless the underlying mixing processes are well known, these situations lead to heavily underdetermined problems. Blind source separation aims at disentangling such mixtures with the least possible prior information on the sources and their mixing processes. Several powerful approaches have recently been developed, which can often provide new or deeper insight into the underlying physics. This tutorial paper briefly discusses some possible applications of blind source separation to the field of plasma physics, in which this concept is still barely known. Two examples are given. The first one shows how concurrent processes in the dynamical response of the electron temperature in a tokamak can be separated. The second example deals with solar spectral imaging in the Extreme UV and shows how empirical temperature maps can be built.Comment: expanded version of an article to appear in Contributions to Plasma Physics (2010

Superconductivity Solves the Monopole Problem for Alice Strings

Alice strings are cosmic strings that turn matter into antimatter. Although they arise naturally in many GUT's, it has long been believed that because of the monopole problem they can have no cosmological effects. We show this conclusion to be false; by using the Langacker-Pi mechanism, monopoles can in fact be annihilated while Alice strings are left intact. This opens up the possibility that they can after all contribute to cosmology, and we mention some particularly important examples.Comment: 16 pages, 7 figures (not included

The use of decomposition methods in real-world treatment benefits evaluation for patients with type 2 diabetes initiating different injectable therapies: findings from the Initiator study

Onur Başer (MEF Author)Background: Determining characteristics of patients likely to benefit from a particular treatment could help physicians set personalized targets. OBJECTIVES: To use decomposition methodology on real-world data to identify the relative contributions of treatment effects and patients' baseline characteristics. METHODS: Decomposition analyses were performed on data from the Initiation of New Injectable Treatment Introduced after Antidiabetic Therapy with Oral-only Regimens (INITIATOR) study, a real-world study of patients with type 2 diabetes started on insulin glargine (GLA) or liraglutide (LIRA). These analyses investigated relative contributions of differences in baseline characteristics and treatment effects to observed differences in 1-year outcomes for reduction in glycated hemoglobin A1c (HbA1c) and treatment persistence. RESULTS: The greater HbA1c reduction seen with GLA compared with LIRA (-1.39% vs. -0.74%) was primarily due to differences in baseline characteristics (HbA1c and endocrinologist as prescribing physician; P < 0.050). Patients with baseline HbA1c of 9.0% or more or evidence of diagnosis codes related to mental illness achieved greater HbA1c reductions with GLA, whereas patients with baseline polypharmacy (6-10 classes) or hypogylcemia achieved greater reductions with LIRA. Decomposition analyses also showed that the higher persistence seen with GLA (65% vs. 49%) was mainly caused by differences in treatment effects (P < 0.001). Patients 65 years and older, those with HbA1c of 9.0% or more, those taking three oral antidiabetes drugs, and those with polypharmacy of more than 10 classes had higher persistence with GLA; patients 18 to 39 years and those with HbA1c of 7.0% to less than 8.0% had higher persistence with LIRA. CONCLUSIONS: Although decomposition does not demonstrate causal relationships, this method could be useful for examining the source of differences in outcomes between treatments in a real-world setting and could help physicians identify patients likely to respond to a particular treatment. Copyright (C) 2017 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.WOS:000419245600004Scopus - Affiliation ID: 60105072PMID: 29241884Science Citation Index Expanded - Social Sciences Citation IndexQ1ArticleUluslararası işbirliği ile yapılan - EVETAralık2017YÖK - 2017-1

Polygenic basis for adaptive morphological variation in a threatened Aotearoa | New Zealand bird, the hihi (Notiomystis cincta)

To predict if a threatened species can adapt to changing selective pressures, it is crucial to understand the genetic basis of adaptive traits, especially in species historically affected by severe bottlenecks. We estimated the heritability of three hihi (Notiomystis cincta) morphological traits known to be under selection: nestling tarsus length, body mass and head-bill length, using 523 individuals and 39,699 single nucleotide polymorphisms (SNPs) from a 50K Affymetrix SNP chip. We then examined the genetic architecture of the traits via chromosome partitioning analyses and genome-wide association scans (GWAS). Heritabilities estimated using pedigree relatedness or genomic relatedness were low. For tarsus length, the proportion of genetic variance explained by each chromosome was positively correlated with its size, and more than one chromosome explained significant variation for body mass and head-bill length. Finally, GWAS analyses suggested many loci of small effect contributing to trait variation for all three traits, although one locus (a SNP within an intron of the transcription factor HEY2) was tentatively associated with tarsus length. Our findings suggest a polygenic nature for the morphological traits, with many small effect size loci contributing to the majority of the variation, similar to results from many other wild populations. However, the small effective population size, polygenic architecture and already low heritabilities suggest that both the total response and rate of response to selection are likely to be limited in hihi