580 research outputs found

    Confining properties of QCD at finite temperature and density

    Full text link
    A disorder parameter detecting dual superconductivty of the vacuum is used as a probe to characterize the confining properties of the phase diagram of two color QCD at finite temperature and density. We obtain evidence for the disappearing of dual superconductivity (deconfinement) induced by a finite density of baryonic matter, as well as for a coincidence of this phenomenon with the restoration of chiral symmetry both at zero and finite density. The saturation transition induced by Pauli blocking is studied as well, and a general warning is given about the possible effects that this unphysical transition could have on the study of the QCD phase diagram at strong values of the gauge coupling.Comment: 13 pages, 23 figure

    Avances en ecotoxicología marina: comparación entre tests de laboratorio y estudios in situ para la evaluación de la calidad ambiental de los sedimentos

    Get PDF
    Ecotoxicology is concerned with describing and predicting the behaviour of substances in the environment and the response of biological systems, and ultimately with assessing the risks associated with emissions. These assessments are complicated from a basic-science point of view and they should be carried out by using integrative assessments. Contaminated sediments are a significant regulatory issue with important science implications. Determining the impact of contaminated sediments is a key element in environmental risk assessment and management of water resources. Tests for ecotoxicology assessment in sediments may be conducted either in the laboratory or field. Both approaches have advantages and disadvantages. Data from different studies performed in laboratory conditions and in field assessments are compared here. The principal advantages of sediment toxicity tests in the laboratory are the possibility to standardize methodologies and to provide direct evidence of sediments as causative agents of toxicity; however, the results are difficult to extrapolate to the field. The results obtained here show the importance of the end point selected in each test and the variability of the responses. Therefore, the results highlight the necessity and importance of the battery-of-tests approach for toxicity assessment. On the other hand, field sediment toxicity has the advantage of empirical evidence and strong correlative indication of the contaminants responsible for toxicity; however, the results obtained from these tests are highly affected by casualty, so it is not possible to isolate a single causative factor. When structural macrofaunal parameters are incorporated into field tests, the results are even more difficult to interpret, because their parameters can be mainly related to organic enrichment or another kind of natural stress, such as salinity gradient, tidal stress conditions, etc.La ecotoxicología es la ciencia que describe y predice el comportamiento de las sustancias en el medio ambiente y las respuestas biológicas del sistema para así, finalmente, evaluar el riesgo asociado con estas emisiones. Estas evaluaciones son difíciles de realizar desde el punto de vista científico y deberían ser elaboradas mediante métodos integrados. Los sedimentos se contemplan, desde el punto de vista científico, como un componente clave en el ecosistema para la evaluación de la calidad ambiental. Los tests de toxicidad de los sedimentos se pueden llevar a cabo tanto en el laboratorio como en el medio teniendo ambos ventajas y desventajas. En este trabajo se comparan los datos obtenidos de distintos experimentos realizados en el laboratorio y un estudio elaborado en el campo. Las principales ventajas de los tests que se han llevado a cabo en el laboratorio fueron la posibilidad de estandarizar la metodología y la evidencia directa que se obtiene de que el sedimento contaminado es el causante de la respuesta biológica; sin embargo, estos resultados son difíciles de extrapolar a la naturaleza. Los resultados obtenidos en este estudio muestran también la importancia de la variable seleccionada en cada test así como la variabilidad en sus respuestas. Por lo tanto, los resultados resaltan la necesidad y la importancia de la utilización de una batería de tests para la evaluación de la toxicidad. Por otra parte, los estudios realizados in situ tienen la ventaja de la evidencia empírica y la fuerte indicación entre la correlación de la toxicidad y los resultados obtenidos; sin embargo, estos resultados están muy afectados por el azar, lo que imposibilita aislar un único factor causante de la respuesta biológica. Los resultados son incluso más difíciles de interpretar cuando se realizan índices estructurales de la macrofauna porque éstos pueden estar más relacionados con el contenido en materia orgánica u otra causa de estrés natural, como puede ser un gradiente de salinidad producido por la marea, etc.Comisión Interministerial de Ciencia y Tecnología (CICYT) de España. AMB94-029

    Effectiveness and feasibility of structured emotionally focused family therapy for parents and adolescents: Protocol of a within-subjects pilot study

    Get PDF
    Mental health issues are widespread among children and adolescents worldwide. Although mental health difficulties may manifest themselves in many different diagnoses, there is growing support for a limited number of underlying transdiagnostic processes. Attachment encompasses a key transdiagnostic mechanism, namely emotional regulation. This study protocol aims to evaluate the feasibility and potential effectiveness of structured emotionally focused family therapy (EFFT), the goal of which is to develop secure attachment between parents and their children to reduce children's vulnerability to mental health problems. A within-subjects design with three waves, a waiting period, treatment, and follow-up, will be conducted. Families will serve as their own controls. Approximately 15 to 20 families with adolescents (aged 12-18 years) as the 'identified patients' will be included. They will participate in 16-21 sessions of EFFT. The study will use a multi-method approach. Self-report questionnaires will be administered repeatedly (i.e., pre-waiting period, pre-treatment, halfway treatment, post-treatment, and follow-up), measuring parent-adolescent attachment, partner-partner attachment, negative interactions, and adolescent psychological complaints. Multi-level analyses will be conducted. Semi-structured interviews will be administered at follow-up to evaluate feasibility and acceptability of EFFT. Treatment integrity will be assessed. The present study is the first to evaluate feasibility of structured EFFT and obtain a first impression of its effectiveness. This information will help us to improve EFFT. Limitations are discussed. Trial registration: Recruitment commenced in June 2022. The approximate trial duration is 36 months. The trial was registered at ClinicalTrials.gov (NCT05657067) on December 9, 2022, and Open Science Framework (https://osf.io/39dt2/) on June 14, 2022

    Ralph B. Stine and Margaret E. Stine v. Henry Girola and Diane Girola and State Underwriters, Inc. : Petition for Rehearing

    Get PDF
    In this paper we present a Remote Control Unit (RCU) that can be attached to any location on a rifle, binoculars, etc., and be operated by a single finger of a soldier without removing his hand from the device. Even for a gloved hand a haptic feedback from the RCU will be realized. A RCU prototype, equipped with a single button, is used as a remote Push-to-Talk (PTT) device for the radio being carried by the soldier. The RCU is powered by the radio waves emitted by this radio. The RCU - being attached to the device - works with a receive unit (RXU) that is attached to and operates the radio. The RCU consists of a RF harvester, energy storage device, a button and a transmitter. Laboratory prototypes are demonstrated

    Where has all the information gone?

    Full text link
    The existence of spacetime singularities is irrelevant for the irreversible appearance of black holes. However, confirmation of the latter's unitary dynamics would require the preparation of a coherent superposition of a tremendous number of appropriate ``Everett worlds''.Comment: 10 pages, 1 figure, Latex - Invited paper for a special Einstein issue of Physics Letters

    Quantum state correction of relic gravitons from quantum gravity

    Get PDF
    The semiclassical approach to quantum gravity would yield the Schroedinger formalism for the wave function of metric perturbations or gravitons plus quantum gravity correcting terms in pure gravity; thus, in the inflationary scenario, we should expect correcting effects to the relic graviton (Zel'dovich) spectrum of the order (H/mPl)^2

    Hydrogen Motion in Magnesium Hydride by NMR

    Get PDF
    In coarse-grained MgH2, the diffusive motion of hydrogen remains too slow (<10^5 hops s^−1) to narrow the H NMR line up to 400 °C. Slow-motion dipolar relaxation time T1D measurements reveal the motion, with hopping rate ωH from 0.1 to 430 s^−1 over the range of 260 to 400 °C, the first direct measurement of H hopping in MgH2. The ωH data are described by an activation energy of 1.72 eV (166 kJ/mol) and attempt frequency of 2.5 × 10^15 s^−1. In ball-milled MgH2 with 0.5 mol % added Nb2O5 catalyst, line-narrowing is evident already at 50 °C. The line shape shows distinct broad and narrow components corresponding to immobile and mobile H, respectively. The fraction of mobile H grows continuously with temperature, reaching ∼30% at 400 °C. This demonstrates that this material’s superior reaction kinetics are due to an increased rate of H motion, in addition to the shorter diffusion paths from ball-milling. In ball-milled MgH2 without additives, the line-narrowed component is weaker and is due, at least in part, to trapped H2 gas. The spin−lattice relaxation rates T1^−1 of all materials are compared, with ball-milling markedly increasing T1^−1. The weak temperature dependence of T1^−1 suggests a mechanism with paramagnetic relaxation centers arising from the mechanical milling

    Boolean Models of Bistable Biological Systems

    Full text link
    This paper presents an algorithm for approximating certain types of dynamical systems given by a system of ordinary delay differential equations by a Boolean network model. Often Boolean models are much simpler to understand than complex differential equations models. The motivation for this work comes from mathematical systems biology. While Boolean mechanisms do not provide information about exact concentration rates or time scales, they are often sufficient to capture steady states and other key dynamics. Due to their intuitive nature, such models are very appealing to researchers in the life sciences. This paper is focused on dynamical systems that exhibit bistability and are desc ribedby delay equations. It is shown that if a certain motif including a feedback loop is present in the wiring diagram of the system, the Boolean model captures the bistability of molecular switches. The method is appl ied to two examples from biology, the lac operon and the phage lambda lysis/lysogeny switch

    Loop Quantum Cosmology, Boundary Proposals, and Inflation

    Full text link
    Loop quantum cosmology of the closed isotropic model is studied with a special emphasis on a comparison with traditional results obtained in the Wheeler-DeWitt approach. This includes the relation of the dynamical initial conditions with boundary conditions such as the no-boundary or the tunneling proposal and a discussion of inflation from quantum cosmology.Comment: 20 pages, 6 figure
    corecore