16,031 research outputs found

    Fractionalization and confinement in the U(1) and Z2Z_2 gauge theories of strongly correlated systems

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    Recently, we have elucidated the physics of electron fractionalization in strongly interacting electron systems using a Z2Z_2 gauge theory formulation. Here we discuss the connection with the earlier U(1) gauge theory approaches based on the slave boson mean field theory. In particular, we identify the relationship between the holons and Spinons of the slave-boson theory and the true physical excitations of the fractionalized phases that are readily described in the Z2Z_2 approach.Comment: 4 page

    A Retrospective Case Study of the Thematic Content of Psychotic Experiences in a First Episode Psychosis Population

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    Background. Historically, the content of psychotic experiences has tended to be of little importance to biological psychiatry, with hallucinations and delusions being seen as symptoms of mental illness rather than meaningful experiences or responses to life circumstances. Aims. This study aims to explore the thematic content of psychotic phenomena in a sample of clients with a first episode of psychosis. Methods. The electronic medical records of 160 services users of two Early Intervention for Psychosis Services were comprehensively reviewed. A thematic analysis was used to explore the thematic content of psychotic symptoms recorded by healthcare professionals. Results. The results illustrate 30 themes and 85 sub-themes. This includes delusional beliefs (e.g. ‚Äúbeing harmed, attacked or killed‚ÄĚ, ‚Äúbeing monitored or followed by others‚ÄĚ, ‚Äúspecial powers or abilities‚ÄĚ) and hallucinations (e.g. ‚Äúcommanding voice‚ÄĚ, ‚Äúderogatory/critical voice‚ÄĚ, ‚Äúcommentary‚ÄĚ). Conclusions. The results illustrate the extensive and varied experience of psychosis within this sample. Based on the findings of this study, it is hoped that future research studies and mental health services will attend to the meaning and content of psychotic experiences

    Extending the Globular Cluster System-Halo Mass Relation to the Lowest Galaxy Masses

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    High mass galaxies, with halo masses M200‚Č•1010M‚äôM_{200} \ge 10^{10} M_{\odot}, reveal a remarkable near-linear relation between their globular cluster (GC) system mass and their host galaxy halo mass. Extending this relation to the mass range of dwarf galaxies has been problematic due to the difficulty in measuring independent halo masses. Here we derive new halo masses based on stellar and HI gas kinematics for a sample of nearby dwarf galaxies with GC systems. We find that the GC system mass--halo mass relation for galaxies populated by GCs holds from halo masses of M200‚ąľ1014M‚äôM_{200} \sim 10^{14} M_{\odot} down to below M200M_{200} ‚ąľ109M‚äô\sim 10^9 M_{\odot}, although there is a substantial increase in scatter towards low masses. In particular, three well-studied ultra diffuse galaxies, with dwarf-like stellar masses, reveal a wide range in their GC-to-halo mass ratios. We compare our GC system--halo mass relation to the recent model of El Badry et al., finding that their fiducial model does not reproduce our data in the low mass regime. This may suggest that GC formation needs to be more efficient than assumed in their model, or it may be due to the onset of stochastic GC occupation in low mass halos. Finally, we briefly discuss the stellar mass-halo mass relation for our low mass galaxies with GCs, and we suggest some nearby dwarf galaxies for which searches for GCs may be fruitful.Comment: 16 pages, 5 figures, accepted for publication in MNRA

    Prospects for the Standard Model Higgs Boson Search in the LEP 2000 Run

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    A study has been performed of the discovery and exclusion potential of LEP expected in 2000 for the Higgs bosonpredicted by the Standard Model. The tradeoff factors betweenincreasing the luminosity at s=204\sqrt{s}=204 GeV and reduced integrated luminosity at s=206\sqrt{s}=206 GeVwere studied. It was shown that only in case some evidencefor a signal is observed it might be worth to increase the integratedluminosity at the lower center-of-mass energy, otherwise,LEP should aim at the highest possible center-of-mass energy.The ultimate expected exclusion limit (at the 95\%\ confidence level)of LEP (with s=206\sqrt{s}=206 GeV) is estimated to be mH‚ąľm_H\sim114 GeV

    Effect of Ewe Breed on Fall Lambing Performance

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    Seasonality of lamb production continues to plague the industry and feeds the large price swings found in the market place. This translates into a fluctuating economic picture for lamb producer, feeder, packer, and consumer. This wide price fluctuation makes accurate financial projections difficult if not impossible. Fall lambing offers a means of spreading the available supply of fresh American lamb over more months, thus reducing the common practice of holding lambs back or over finishing lambs

    Confinement of Slave-Particles in U(1) Gauge Theories of Strongly-Interacting Electrons

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    We show that slave particles are always confined in U(1) gauge theories of interacting electron systems. Consequently, the low-lying degrees of freedom are different from the slave particles. This is done by constructing a dual formulation of the slave-particle representation in which the no-double occupany constraint becomes linear and, hence, soluble. Spin-charge separation, if it occurs, is due to the existence of solitons with fractional quantum numbers

    Scaling and Crossover Functions for the Conductance in the Directed Network Model of Edge States

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    We consider the directed network (DN) of edge states on the surface of a cylinder of length L and circumference C. By mapping it to a ferromagnetic superspin chain, and using a scaling analysis, we show its equivalence to a one-dimensional supersymmetric nonlinear sigma model in the scaling limit, for any value of the ratio L/C, except for short systems where L is less than of order C^{1/2}. For the sigma model, the universal crossover functions for the conductance and its variance have been determined previously. We also show that the DN model can be mapped directly onto the random matrix (Fokker-Planck) approach to disordered quasi-one-dimensional wires, which implies that the entire distribution of the conductance is the same as in the latter system, for any value of L/C in the same scaling limit. The results of Chalker and Dohmen are explained quantitatively.Comment: 10 pages, REVTeX, 2 eps figure

    Strength and power training in rehabilitation: underpinning principles and practical strategies to return athletes to high performance

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    Injuries have a detrimental impact on team and individual athletic performance. Deficits in maximal strength, rate of force development (RFD), and reactive strength are commonly reported following several musculoskeletal injuries. This article first examines the available literature to identify common deficits in fundamental physical qualities following injury, specifically strength, rate of force development and reactive strength. Secondly, evidence-based strategies to target a resolution of these residual deficits will be discussed to reduce the risk of future injury. Examples to enhance practical application and training programmes have also been provided to show how these can be addressed

    Search and You Shall Find: Making Oral Histories Searchable with Transcripts and Metadata

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    Presentation on creating transcripts and metadata for oral history collections, including background information, tips, tools, and lessons learned
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