777 research outputs found

    On the Spontaneous CP Breaking in the Higgs Sector of the Minimal Supersymmetric Standard Model

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    We revise a recently proposed mechanism for spontaneous CP breaking at finite temperature in the Higgs sector of the Minimal Supersymmetric Standard Model, based on the contribution of squarks, charginos and neutralinos to the one-loop effective potential. We have included plasma effects for all bosons and added the contribution of neutral scalar and charged Higgses. While the former have little effect, the latter provides very strong extra constraints on the parameter space and change drastically the previous results. We find that CP can be spontaneously broken at the critical temperature of the electroweak phase transition without any fine-tuning in the parameter space.Comment: 9 pages, LATEX, 3 appended postscript figures, IEM-FT-76/9

    The Higgs as a Portal to Plasmon-like Unparticle Excitations

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    A renormalizable coupling between the Higgs and a scalar unparticle operator O_U of non-integer dimension d_U<2 triggers, after electroweak symmetry breaking, an infrared divergent vacuum expectation value for O_U. Such IR divergence should be tamed before any phenomenological implications of the Higgs-unparticle interplay can be drawn. In this paper we present a novel mechanism to cure that IR divergence through (scale-invariant) unparticle self-interactions, which has properties qualitatively different from the mechanism considered previously. Besides finding a mass gap in the unparticle continuum we also find an unparticle pole reminiscent of a plasmon resonance. Such unparticle features could be explored experimentally through their mixing with the Higgs boson.Comment: 12 LaTeX pages, 2 figure

    Surco en cabeza femoral como signo de inestabilidad de cadera en pacientes con Síndrome de Down.

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    La inestabilidad de cadera en pacientes afectos de síndrome de Down es una entidad poco frecuente, en la actualidad todavía existe controversia sobre las anomalías anatómicas asociadas. El objetivo de este trabajo es describir los cambios anatómicos en las caderas de pacientes con inestabilidad en el síndrome de Down (SD). Hemos revisado las tomografías computarizadas (TC) de los pacientes afectos de luxación de cadera con SD. A tres de los 7 pacientes intervenidos en nuestro centro, se les había realizado TC de caderas. En todas las TC mostraban la presen - cia de lesión lineal vertical (surco) localizada en región epifisaria, atravesando la fisis, de localización antero-interna. Creemos que la posición adoptada cuando duermen (flexión, aducto y rotación interna) puede producir hiperpresión de la cabeza femoral sobre la ceja acetabular posterior, produciendo un surco vertical. La presencia de esta lesión puede ser sugestiva de inestabilidad subclínica de cadera en ausencia de episodio de luxación.Hip instability in patients with Down syndrome is a rare entity, currently there is still controversy about the associated anatomical anomalies. The aim of the study is to describe the anatomical changes in the hips of patients with instability in Down syndrome (DS). We have reviewed the computed tomography (CT) of patients with hip dislocation with SD. Three of the 7 patients treated in our center are performed CT had hips. All CT showed the presence of vertical linear lesion (groove) located in epiphyseal region, crossing the physis, antero-internal location. We believe that the position taken when sleeping (flexion, adduction and internal rotation) can produce overpressure of the femoral head over the posterior acetabular rim, producing a vertical groove. The presence of this lesion can be suggestive of subclinical instability in the absence of hip dislocation

    New analytical method for determination of phthalates in wastewater by on line lc-gc-ms using the totad interface and fraction collector

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    There is an increasing demand for automatic, reliable and sensitive analytical methods for determining trace levels of phthalic acid esters (PAEs) in environmental samples. While on line coupled liquid chromatography-gas chromatography (LC-GC) has been proof to be a powerful tool for trace-level analyses in complex matrices, the present work presents a new totally automated on line LC-GC method, using the Through Oven Transfer Adsorption Desorption (TOTAD) interface, for the analysis of four of the main phthalates, dibuthyl phthalate (DBP), diethyl phthalate (DEP), dimethyl phthalate (DMP) and diethylhexyl phthalate (DEHP), in a matrix as complex as leachate. The sample is directly injected into the LC injector valve with no sample pretreatment other than simple filtration. The LC step separates the target analytes from matrix interference. Two different LC fractions are collected in a purposely designed fraction collector and then transferred to the TOTAD interface, which concentrates the analytes, totally eliminates the solvent and transfers the analytes to the GC-MS system, where the analysis is carried out. The LOD of the method varied from 0.1 µg/L (DEHP) to 1.4 µg/L (DMP), RSD for retention time below 0.14% and for absolute peak areas below 12% and linearity from 1 µg/L to 1000 µg/L (R2 > 0.99), except in the case of DEHP (linearity from 1 to 250 µg/L, R2 = 0.94). The method was applied to the analysis of the target analytes in samples collected from a municipal solid waste (MSW) landfill in Rosario (Argentina).Fil: Espinosa, F.J.. Universidad de Castilla-La Mancha; EspañaFil: Toledano, R.M.. Universidad de Castilla-La Mancha; EspañaFil: Andini, Juan Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Cortés, J.M.. Universidad de Castilla-La Mancha; EspañaFil: Vázquez, A.M.. Universidad de Castilla-La Mancha; Españ

    Inestabilidad patelofemoral en niños con Síndrome de Down

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    La inestabilidad patelofemoral en el síndrome de Down se presenta en el contexto de hiperlaxitud e inmadurez esquelética suponiendo un reto en el tratamiento. Nuestro objetivo es valorar el resultado clínico-funcional de la cirugía de partes blandas, en estos pacientes hiperlaxos e inmaduros esqueléticamente. Hemos revisado retrospectivamente a los pacientes con síndrome de Down e inmadurez esquelética intervenidos por inestabilidad patelofemoral con seguimiento hasta el cierre fisario. Seis pacientes (9 rodillas) con media de edad de 12,4 años fueron incluidos. El grado de inestabilidad patelofemoral prequirúrgica (clasificación de Dugdale) mostró 1 (11,1%) caso grado 2; 2 (22,2%) casos grado 3 y 6 (66,6%) casos grado 4. El grado de función patelar (según Insall) al alcanzar la madurez esquelética fue malo en un caso (recidiva de la luxación), bueno en 2 y excelente en 6. En definitiva, los procedimientos sobre partes blandas pueden ser suficientes en pacientes con síndrome de Down.Patelofemoral instability in Down syndrome´s patients appears in hiperlaxity and open physis context. Our aim is to make a retrospective clinical-functional assessment of the soft tissue procedure treatment of patellofemoral instability in patients with Down Syndrome skeletally immature (open physeal), following them until the physeal closure. We have included six patients (9 knees) with a mean age of 12.4 years old. Patellar instability (Dugdale´s classification) distribution was 1 (11.1%) cases degree ll; 2 (22.2%) cases degree lll and 6 (66.6%) cases degree IV. Patellar function assessed by Insall score at follow up was excellent in 6 of the cases, good in 2 cases and bad in one case (recurrent dislocation). In summary, a proximal soft tissues procedure in Down syndrome patients could be enough for patellar instability treatment

    Hydrodynamic obstruction to bubble expansion

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    We discuss a hydrodynamic obstruction to bubble wall acceleration during a cosmological first-order phase transition. The obstruction results from the heating of the plasma in the compression wave in front of the phase transition boundary. We provide a simple criterion for the occurrence of the obstruction at subsonic bubble wall velocity in terms of the critical temperature, the phase transition temperature, and the latent heat of the model under consideration. The criterion serves as a sufficient condition of subsonic bubble wall velocities as required by electroweak baryogenesis.Comment: 18 pages, 4 figures; comments and reference added, published versio

    Forest landscape restoration in the drylands of Latin America

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    Forest Landscape Restoration (FLR) involves the ecological restoration of degraded forest landscapes, with the aim of benefiting both biodiversity and human well-being. We first identify four fundamental principles of FLR, based on previous definitions. We then critically evaluate the application of these principles in practice, based on the experience gained during an international, collaborative research project conducted in six dry forest landscapes of Latin America. Research highlighted the potential for FLR; tree species of high socioeconomic value were identified in all study areas, and strong dependence of local communities on forest resources was widely encountered, particularly for fuelwood. We demonstrated that FLR can be achieved through both passive and active restoration approaches, and can be cost-effective if the increased provision of ecosystem services is taken into account. These results therefore highlight the potential for FLR, and the positive contribution that it could make to sustainable development. However, we also encountered a number of challenges to FLR implementation, including the difficulty of achieving strong engagement in FLR activities among local stakeholders, lack of capacity for community-led initiatives, and the lack of an appropriate institutional and regulatory environment to support restoration activities. Successful implementation of FLR will require new collaborative alliances among stakeholders, empowerment and capacity building of local communities to enable them to fully engage with restoration activities, and an enabling public policy context to enable local people to be active participants in the decision making process. © 2012 by the author(s). Published here under license by the Resilience Alliance

    Inferior lateral genicular artery injury during anterior cruciate ligament reconstruction surgery

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    We report a case of inferior lateral genicular artery (ILG) injury during anterior cruciate ligament (ACL) reconstruction surgery with lateral partial meniscectomy. This is a rare arthroscopy complication. A review of the literature has been made with the aim to define the anatomy of ILG across the lateral articular line and the risk of lesion during knee arthroscopy. We propose embolization as a good treatment option for this type of injurie

    Resummation Methods at Finite Temperature: The Tadpole Way

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    We examine several resummation methods for computing higher order corrections to the finite temperature effective potential, in the context of a scalar ϕ4\phi^4 theory. We show by explicit calculation to four loops that dressing the propagator, not the vertex, of the one-loop tadpole correctly counts ``daisy'' and ``super-daisy'' diagrams.Comment: 18 pages, LaTeX, CALT-68-1858, HUTP-93-A011, EFI-93-2

    Energy Budget of Cosmological First-order Phase Transitions

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    The study of the hydrodynamics of bubble growth in first-order phase transitions is very relevant for electroweak baryogenesis, as the baryon asymmetry depends sensitively on the bubble wall velocity, and also for predicting the size of the gravity wave signal resulting from bubble collisions, which depends on both the bubble wall velocity and the plasma fluid velocity. We perform such study in different bubble expansion regimes, namely deflagrations, detonations, hybrids (steady states) and runaway solutions (accelerating wall), without relying on a specific particle physics model. We compute the efficiency of the transfer of vacuum energy to the bubble wall and the plasma in all regimes. We clarify the condition determining the runaway regime and stress that in most models of strong first-order phase transitions this will modify expectations for the gravity wave signal. Indeed, in this case, most of the kinetic energy is concentrated in the wall and almost no turbulent fluid motions are expected since the surrounding fluid is kept mostly at rest.Comment: 36 pages, 14 figure
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