288 research outputs found

    Form Factors for Quasi-particles in c=1 Conformal Field Theory

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    The non-Fermi liquid physics at the edge of fractional quantum Hall systems is described by specific chiral Conformal Field Theories with central charge c=1. The charged quasi-particles in these theories have fractional charge and obey a form of fractional statistics. In this paper we study form factors, which are matrix elements of physical (conformal) operators, evaluated in a quasi-particle basis that is organized according to the rules of fractional exclusion statistics. Using the systematics of Jack polynomials, we derive selection rules for a special class of form factors. We argue that finite temperature Green's functions can be evaluated via systematic form factor expansions, using form factors such as those computed in this paper and thermodynamic distribution functions for fractional exclusion statistics. We present a specific case study where we demonstrate that the form factor expansion shows a rapid convergence.Comment: 36 pages, 1 postscript figur

    Quasi-particles for quantum Hall edges

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    We discuss a quasi-particle formulation of effective edge theories for the fractional quantum Hall effect. Fundamental quasi-particles for the Laughlin state with filling fraction \nu =1/3 are edge electrons of charge -e and edge quasi-holes of charge +e/3. These quasi-particles satisfy exclusion statistics in the sense of Haldane. We exploit algebraic properties of edge electrons to derive a kinetic equation for charge transport between a \nu=1/3 fractional quantum Hall edge and a normal metal.Comment: Latex, 6 pages, Contribution to the proceedings of the XXXIVth Rencontres de Moriond `Quantum Physics at Mesoscopic Scale

    `Composite particles' and the eigenstates of Calogero-Sutherland and Ruijsenaars-Schneider

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    We establish a one-to-one correspondance between the ''composite particles'' with NN particles and the Young tableaux with at most NN rows. We apply this correspondance to the models of Calogero-Sutherland and Ruijsenaars-Schneider and we obtain a momentum space representation of the ''composite particles'' in terms of creation operators attached to the Young tableaux. Using the technique of bosonisation, we obtain a position space representation of the ''composite particles'' in terms of products of vertex operators. In the special case where the ''composite particles'' are bosons and if we add one extra quasiparticle or quasihole, we construct the ground state wave functions corresponding to the Jain series ν=p/(2np±1)\nu =p/(2np\pm 1) of the fractional quantum Hall effect.Comment: latex calcomp2.tex, 5 files, 30 pages [SPhT-T99/080], submitted to J. Math. Phy

    Rituximab administration in third trimester of pregnancy suppresses neonatal B-cell development

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    We describe the effect on the neonate of administration of rituximab to a woman with idiopathic thrombocytopenic purpura (ITP). Rituximab, an anti-CD20 antibody, was given weekly for 4 weeks to a woman with ITP in her third trimester of pregnancy. One month after the last rituximab administration a healthy girl was born. She had normal growth and development during the first six months. At birth, B-lymphocytes were not detectable. Rituximab levels in mother and neonate were 24000 and 6700 ng/mL, respectively. Only 7 cases of rituximab administration during pregnancy were described. No adverse events are described for fetus and neonate. We demonstrate that rituximab passes the placenta and inhibits neonatal B-lymphocyte development. However, after 6 months B-lymphocyte levels normalized and vaccination titres after 10 months were adequate. No infection-related complications occurred. Rituximab administration during pregnancy appears to be safe for the child but further studies are warranted. Copyright © 2008 D. T. Klink et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. 1

    Газоносність вугільних пластів та фізико-механічнині властивості порід покрівлі і підошви поля шахти № 1 ”Тяглівська” Львівсько-Волинського басейну

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    Сопоставлены данные по изучению газоносности угольных пластов поля шахты № 1 ―Тягловская‖ и физико-механическим свойствам пород их непосредственной кровли и подошвы. Благоприятными яляются условия для выработки пластов b4, n8 в, n8. Несколько сложнее – для пластов n9, n7 в, n7 1, что вызвано низкой стойкостью пород кровли. Наиболее сложной прогнозируется ситуация для эксплуатации пласта n7 из-за низной стойкости и способности его кровли к обрушениям. Угольные пласты (кроме b4) находятся в метановой зоне. Их газоносность значительна, содержание метана в газовой смеси высокое. Это будет составлять дополнительные трудности при эксплуатации.Data on studies of the gas-bearing potential of coal seams of the Tyagliv-1 mine field are correlated as well as physical-mechanical properties of their immediate base and roof. Favorable conditions are known to exist for working of the seams b4, n8 в, n8. Somewhat more composite ones are observed for the seams n9, n7в, n7 1 that was caused by low stability of the roof rocks. The most composite situation is forecasted for exploitation of the seam n7 one to low stability and ability of its roof for landslides. Coal seams (exsepting b4) lie in the methane zone. Their gas-bearing potential is suffcient, methane content in a gas mixture is high. That will cause additional difficalties in the process of exploitation

    Psychopathological and Neurobiological Overlap Between Anorexia Nervosa and Self-Injurious Behavior: A Narrative Review and Conceptual Hypotheses

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    Empirical evidence and clinical observations suggest a strong -yet under acknowledged-link between anorexia nervosa (AN) and non-suicidal self-injurious behavior (NSSI). By reviewing the literature on the psychopathology and neurobiology of AN and NSSI, we shed light on their relationship. Both AN and NSSI are characterized by disturbances in affect regulation, dysregulation of the reward circuitry and the opioid system. By formulating a reward-centered hypothesis, we explain the overlap between AN and NSSI. We propose three approaches understanding the relationship between AN and NSSI, which integrate psychopathology and neurobiology from the perspective of self-destructiveness: (1) a nosographical approach, (2) a research domain (RDoC) approach and (3) a network analysis approach. These approaches will enhance our knowledge of the underlying neurobiological substrates and may provide groundwork for the development of new treatment options for disorders of self-destructiveness, like AN and NSSI. In conclusion, we hypothesize that self-destructiveness is a new, DSM-5-transcending concept or psychopathological entity that is reward-driven, and that both AN and NSSI could be conceptualized as disorders of self-destructiveness

    МОДЕЛИРОВАНИЕ ПРОЦЕССОВ ДОСТАВКИ ВСПОМОГАТЕЛЬНыХ ГРУЗОПОТОКОВ ВНУТРИШАХТНОГО ТРАНСПОРТА С УЧЕТОМ ХАРАКТЕРИСТИКИ ТРАССы

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    Розглянуто специфічні задачі внутрішахтного транспорту. Запропоновано використовувати метод Флойду-Уоршелла для моделювання допоміжних вантажопотоків з урахуванням характеристики мар- шруту. Наведені результати застосування цього методу для своєчасної доставки матеріальних потоків вугільних шахт у підготовчі вибої. Рассмотрены специфические задачи внутришахтного транспорта. Предложено использовать метод Флойда – Уоршелла для моделирования вспомогательных грузопотоков с учетом характеристики трас- сы. Приведены результаты применения используемого метода для оперативной доставки материаль- ных потоков угольных шахт в подготовительные забои

    K-matrices for non-abelian quantum Hall states

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    Two fundamental aspects of so-called non-abelian quantum Hall states (the q-pfaffian states and more general) are a (generalized) pairing of the participating electrons and the non-abelian statistics of the quasi-hole excitations. In this paper, we show that these two aspects are linked by a duality relation, which can be made manifest by considering the K-matrices that describe the exclusion statistics of the fundamental excitations in these systems.Comment: LaTeX, 12 page

    Design of a randomised controlled trial on immune effects of acidic and neutral oligosaccharides in the nutrition of preterm infants: carrot study

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    <p>Abstract</p> <p>Background</p> <p>Prevention of serious infections in preterm infants is a challenge, since prematurity and low birth weight often requires many interventions and high utility of devices. Furthermore, the possibility to administer enteral nutrition is limited due to immaturity of the gastrointestinal tract in the presence of a developing immune system. In combination with delayed intestinal bacterial colonisation compared with term infants, this may increase the risk for serious infections. Acidic and neutral oligosaccharides play an important role in the development of the immune system, intestinal bacterial colonisation and functional integrity of the gut. This trial aims to determine the effect of enteral supplementation of acidic and neutral oligosaccharides on infectious morbidity (primary outcome), immune response to immunizations, feeding tolerance and short-term and long-term outcome in preterm infants. In addition, an attempt is made to elucidate the role of acidic and neutral oligosaccharides in postnatal modulation of the immune response and postnatal adaptation of the gut.</p> <p>Methods/Design</p> <p>In a double-blind placebo controlled randomised trial, 120 preterm infants (gestational age <32 weeks and/or birth weight <1500 gram) are randomly allocated to receive enteral acidic and neutral oligosaccharides supplementation (20%/80%) or placebo supplementation (maltodextrin) between day 3 and 30 of life. Primary outcome is infectious morbidity (defined as the incidence of serious infections). The role of acidic and neutral oligosaccharides in modulation of the immune response is investigated by determining the immune response to DTaP-IPV-Hib(-HBV)+PCV7 immunizations, plasma cytokine concentrations, faecal Calprotectin and IL-8. The effect of enteral acidic and neutral oligosaccharides supplementation on postnatal adaptation of the gut is investigated by measuring feeding tolerance, intestinal permeability, intestinal viscosity, and determining intestinal microflora. Furthermore, short-term and long-term outcome are evaluated.</p> <p>Discussion</p> <p>Especially preterm infants, who are at increased risk for serious infections, may benefit from supplementation of prebiotics. Most studies with prebiotics only focus on the colonisation of the intestinal microflora. However, the pathways how prebiotics may influence the immune system are not yet fully understood. Studying the immune modulatory effects is complex because of the multicausal risk of infections in preterm infants. The combination of neutral oligosaccharides with acidic oligosaccharides may have an increased beneficial effect on the immune system. Increased insight in the effects of prebiotics on the developing immune system may help to decrease the (infectious) morbidity and mortality in preterm infants.</p> <p>Trial registration</p> <p>Current Controlled Trials ISRCTN16211826.</p

    Finite-temperature form factors in the free Majorana theory

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    We study the large distance expansion of correlation functions in the free massive Majorana theory at finite temperature, alias the Ising field theory at zero magnetic field on a cylinder. We develop a method that mimics the spectral decomposition, or form factor expansion, of zero-temperature correlation functions, introducing the concept of "finite-temperature form factors". Our techniques are different from those of previous attempts in this subject. We show that an appropriate analytical continuation of finite-temperature form factors gives form factors in the quantization scheme on the circle. We show that finite-temperature form factor expansions are able to reproduce expansions in form factors on the circle. We calculate finite-temperature form factors of non-interacting fields (fields that are local with respect to the fundamental fermion field). We observe that they are given by a mixing of their zero-temperature form factors and of those of other fields of lower scaling dimension. We then calculate finite-temperature form factors of order and disorder fields. For this purpose, we derive the Riemann-Hilbert problem that completely specifies the set of finite-temperature form factors of general twist fields (order and disorder fields and their descendants). This Riemann-Hilbert problem is different from the zero-temperature one, and so are its solutions. Our results agree with the known form factors on the circle of order and disorder fields.Comment: 40 pp.; v2: 42 pp., refs and acknowledgment added, typos corrected, description of general matrix elements corrected and extended; v3: 47 pp., appendix adde
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