869 research outputs found

    Top-Quark Production and Decay in the MSSM

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    We review the features of top-quark decays and loop-induced effects in the production cross section and CP-violating observables of e+e- -> t t-bar which are specific to the R-parity conserving Minimal Supersymmetric Standard Model (MSSM).Comment: LaTeX, 28 pages, 10 figures included, uses cite.sty. Contribution to the proceedings of the 2nd Joint ECFA/DESY Workshop on Physics and Detectors for a Linear Electron-Positron Collider. References adde

    Supersymmetry Tests from a Combined Analysis of Chargino and Charged Higgs Boson Pair Production at a 1 TeV Linear Collider

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    We consider the production of chargino and charged Higgs boson pairs at future linear colliders for c.m. energies in the one TeV range. Working in the MSSM under the assumption of a "moderately" light SUSY scenario, we compute the leading (double) and next-to leading (linear) supersymmetric logarithmic terms of the so-called "Sudakov expansion" at one loop. We show that a combined analysis of the slopes of the chargino and of the charged Higgs production cross sections would offer a simple possibility for determining tanβ\tan\beta for large (10\gtrsim 10) values and an allowed strip in the (M2,μM_2,\mu) plane. This could provide a strong consistency test of the considered supersymmetric model.Comment: 4 pages, 4 Encapsulated PostScript Figure

    A new cell primo-culture method for freshwater benthic diatom communities

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    A new cell primo-culture method was developed for the benthic diatom community isolated from biofilm sampled in rivers. The approach comprised three steps: (1) scraping biofilm from river pebbles, (2) diatom isolation from biofilm, and (3) diatom community culture. With a view to designing a method able to stimulate the growth of diatoms, to limit the development of other microorganisms, and to maintain in culture a community similar to the original natural one, different factors were tested in step 3: cell culture medium (Chu No 10 vs Freshwater “WC” medium modified), cell culture vessel, and time of culture. The results showed that using Chu No 10 medium in an Erlenmeyer flask for cell culture was the optimal method, producing enough biomass for ecotoxicological tests as well as minimising development of other microorganisms. After 96 h of culture, communities differed from the original communities sampled in the two rivers studied. Species tolerant of eutrophic or saprobic conditions were favoured during culture. This method of diatom community culture affords the opportunity to assess, in vitro, the effects of different chemicals or effluents (water samples andindustrial effluents) on diatom communities, as well as on diatom cells, from a wide range of perspectives

    Perfil de los pacientes con trastorno adaptativo que acuden a las farmacias comunitarias españolas

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    Objetivo: El objetivo principal era conocer los perfiles de los sujetos que cumplían los criterios diagnósticos de trastorno adaptativo en la consulta habitual de las farmacias comunitarias españolas.Material y métodos: Estudio transversal de ámbito nacional sobre una muestra de 1.512 sujetos. Se evaluaron las características del perfil socio-demográfico y clínico, así como del estado de ánimo y de salud, recogidos mediante entrevista con el farmacéutico. El estado de ánimo se valoró mediante una escala de expresiones faciales con gradación del 1 (risa) al 7 (llanto). El estado de salud se valoró mediante preguntas sobre movilidad, cuidado personal, dolor y malestar, sueño y energía, ánimo, habilidades interpersonales y cognición. La duración total de la fase experimental fue de 7 meses. Se utilizó básicamente estadística descriptiva.Resultados: La población de sujetos estudiados que cumplían criterios diagnósticos de trastorno adaptativo tenía una edad media de 43,1±14,8 años, siendo un 63,0 % mujeres. El 61,8 % de los sujetos consultó por estado de ánimo deprimido con un tiempo de evolución de la mayor parte del día en el 60,8 % de ellos y durante más de 2 semanas en el 79,0 % de ellos. El 37,1 % de los sujetos valoró su estado de ánimo como triste (gradación 5-7). El 38,1 % de sujetos presentaba estado de ánimo deprimido y ansiedad. El 12,0 % de los sujetos presentaba síntomas depresivos subclínicos. Se observó relación significativa (p<0,001) entre problemas emocionales y salud física.Conclusión: Los síntomas más frecuentes de los pacientes que refieren sintomatología de trastorno adaptivo en este estudio son consulta frecuente en la farmacia comunitaria, lo que podría sugerir que los farmacéuticos comunitarios podrían ayudar con su intervención farmacéutica en la detección precoz y abordaje de esta patología

    Sfermion Precision Measurements at a Linear Collider

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    At future e+- e- linear colliders, the event rates and clean signals of scalar fermion production - in particular for the scalar leptons - allow very precise measurements of their masses and couplings and the determination of their quantum numbers. Various methods are proposed for extracting these parameters from the data at the sfermion thresholds and in the continuum. At the same time, NLO radiative corrections and non-zero width effects have been calculated in order to match the experimental accuracy. The substantial mixing expected for the third generation sfermions opens up additional opportunities. Techniques are presented for determining potential CP-violating phases and for extracting tan(beta) from the stau sector, in particular at high values. The consequences of possible large mass differences in the stop and sbottom system are explored in dedicated analyses.Comment: Expanded version of contributions to the proceedings of ICHEP'02 (Amsterdam) and LCWS 2002 (Jeju Island

    The Antioxidant Potential of the Mediterranean Diet in Patients at High Cardiovascular Risk: An In-Depth Review of the PREDIMED

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    Cardiovascular disease (CVD) is the leading global cause of death. Diet is known to be important in the prevention of CVD. The PREDIMED trial tested a relatively low-fat diet versus a high-fat Mediterranean diet (MedDiet) for the primary prevention of CVD. The resulting reduction of the CV composite outcome resulted in a paradigm shift in CV nutrition. Though many dietary factors likely contributed to this effect, this review focuses on the influence of the MedDiet on endogenous antioxidant systems and the effect of dietary polyphenols. Subgroup analysis of the PREDIMED trial revealed increased endogenous antioxidant and decreased pro-oxidant activity in the MedDiet groups. Moreover, higher polyphenol intake was associated with lower incidence of the primary outcome, overall mortality, blood pressure, inflammatory biomarkers, onset of new-onset type 2 diabetes mellitus (T2DM), and obesity. This suggests that polyphenols likely contributed to the lower incidence of the primary event in the MedDiet groups. In this article, we summarize the potential benefits of polyphenols found in the MedDiet, specifically the PREDIMED cohort. We also discuss the need for further research to confirm and expand the findings of the PREDIMED in a non-Mediterranean population and to determine the exact mechanisms of action of polyphenols

    Does Language Dominance Affect Cognitive Performance In Bilinguals? Lifespan Evidence From Preschoolers Through Older Adults On Card Sorting, Simon, And Metalinguistic Tasks

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    This study explores the extent to which a bilingual advantage can be observed for three tasks in an established population of fully fluent bilinguals from childhood through adulthood. Welsh-English simultaneous and early sequential bilinguals, as well as English monolinguals, aged 3 years through older adults, were tested on three sets of cognitive and executive function tasks. Bilinguals were Welsh-dominant, balanced, or English-dominant, with only Welsh, Welsh and English, or only English at home. Card sorting, Simon, and a metalinguistic judgment task (650, 557, and 354 participants, respectively) reveal little support for a bilingual advantage, either in relation to control or globally. Primarily there is no difference in performance across groups, but there is occasionally better performance by monolinguals or persons dominant in the language being tested, and in one case-in one condition and in one age group-lower performance by the monolinguals. The lack of evidence for a bilingual advantage in these simultaneous and early sequential bilinguals suggests the need for much closer scrutiny of what type of bilingual might demonstrate the reported effects, under what conditions, and why.published_or_final_versio

    Stride: a flexible software platform for high-performance ultrasound computed tomography

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    BACKGROUND AND OBJECTIVE: Advanced ultrasound computed tomography techniques like full-waveform inversion are mathematically complex and orders of magnitude more computationally expensive than conventional ultrasound imaging methods. This computational and algorithmic complexity, and a lack of open-source libraries in this field, represent a barrier preventing the generalised adoption of these techniques, slowing the pace of research, and hindering reproducibility. Consequently, we have developed Stride, an open-source Python library for the solution of large-scale ultrasound tomography problems. METHODS: On one hand, Stride provides high-level interfaces and tools for expressing the types of optimisation problems encountered in medical ultrasound tomography. On the other, these high-level abstractions seamlessly integrate with high-performance wave-equation solvers and with scalable parallelisation routines. The wave-equation solvers are generated automatically using Devito, a domain-specific language, and the parallelisation routines are provided through the custom actor-based library Mosaic. RESULTS: We demonstrate the modelling accuracy achieved by our wave-equation solvers through a comparison (1) with analytical solutions for a homogeneous medium, and (2) with state-of-the-art modelling software applied to a high-contrast, complex skull section. Additionally, we show through a series of examples how Stride can handle realistic numerical and experimental tomographic problems, in 2D and 3D, and how it can scale robustly from a local multi-processing environment to a multi-node high-performance cluster. CONCLUSIONS: Stride enables researchers to rapidly and intuitively develop new imaging algorithms and to explore novel physics without sacrificing performance and scalability. This will lead to faster scientific progress in this field and will significantly ease clinical translation

    Does grazing pressure modify diuron toxicity in a biofilm community?

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    Herbicides affect the structure and functional parameters of fluvial biofilm. Diuron is toxic to primary producers and disrupts endocrine activity. Here, we studied the interaction between this toxicant and several biological compartments in a simple food chain composed of herbivores (the snail Physella [Costatella] acuta) and biofilm. We used indoor experimental channels to which Diuron was added at a realistic concentration (2 μg/L). Bacterial survival and chlorophyll-a and photosynthetic activity were analyzed in the biofilm. We monitored biomass, mortality, reproduction, and motility as end points in the freshwater snail P. acuta. Our results showed that bacterial survival and photosynthetic activity were sensitive to Diuron. Snails were not affected by the herbicide at the concentration tested. No significant interactions between the toxicant and grazers were observed on the biofilm. Reproductive traits, however, were slightly affected, indicating a possible endocrine disruption
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