971 research outputs found

    Los sectores populares en la Revolución

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    Se describe a modo de resumen el siguiente texto del autor: "Yo voy a hablar tratando de ser breve. Quiero comentar algunas cosas con respecto a la participación popular en el período de la revolución, ya que durante muchos años me dediqué a investigar estos temas de lo que llamamos ‘campo de la historia popular’. Que en realidad es la historia de aquellos que son muy difíciles de rastrear históricamente, valga la redundancia; es decir, no Belgrano, Moreno, San Martín, Artigas, Ramírez… todos ellos pertenecen a las clases altas, ¿no?, sino los que están por debajo de ellos: aquellos que dejan mucho menos huellas en la historia, aquellos que –yo digo siempre– no tienen nombres de calles, pero que también son protagonistas históricos"

    Pathway to a Compact SASE FEL Device

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    Newly developed high peak power lasers have opened the possibilities of driving coherent light sources operating with laser plasma accelerated beams and wave undulators. We speculate on the combination of these two concepts and show that the merging of the underlying technologies could lead to new and interesting possibilities to achieve truly compact, coherent radiator devices

    Vacuum fluctuation force on a rigid Casimir cavity in a gravitational field

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    We discuss the possibility of verifying the equivalence principle for the zero-point energy of quantum electrodynamics, by evaluating the force, produced by vacuum fluctuations, acting on a rigid Casimir cavity in a weak gravitational field. The resulting force has opposite direction with respect to the gravitational acceleration; the order of magnitude for a multi-layer cavity configuration is derived and experimental feasibility is discussed, taking into account current technological resources.Comment: 13 pages, Latex. In the revised version, the presentation has been improve

    Social Firms as a means of vocational recovery for people with mental illness: a UK survey.

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    RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are.BACKGROUND: Employment is associated with better quality of life and wellbeing in people with mental illness. Unemployment is associated with greater levels of psychological illness and is viewed as a core part of the social exclusion faced by people with mental illness. Social Firms offer paid employment to people with mental illness but are under-investigated in the UK. The aims of this phase of the Social Firms A Route to Recovery (SoFARR) project were to describe the availability and spread of Social Firms across the UK, to outline the range of opportunities Social Firms offer people with severe mental illness and to understand the extent to which they are employed within these firms. METHOD: A UK national survey of Social Firms, other social enterprises and supported businesses was completed to understand the extent to which they provide paid employment for the mentally ill. A study-specific questionnaire was developed. It covered two broad areas asking employers about the nature of the Social Firm itself and about the employees with mental illness working there. RESULTS: We obtained returns from 76 Social Firms and social enterprises / supported businesses employing 692 people with mental illness. Forty per cent of Social Firms were in the south of England, 24% in the North and the Midlands, 18% in Scotland and 18% in Wales. Other social enterprises/supported businesses were similarly distributed. Trading activities were confined mainly to manufacturing, service industry, recycling, horticulture and catering. The number of employees with mental illness working in Social Firms and other social enterprises/supported businesses was small (median of 3 and 6.5 respectively). Over 50% employed people with schizophrenia or bipolar disorder, though the greatest proportion of employees with mental illness had depression or anxiety. Over two thirds of Social Firms liaised with mental health services and over a quarter received funding from the NHS or a mental health charity. Most workers with mental illness in Social Firms had been employed for over 2 years. CONCLUSIONS: Social Firms have significant potential to be a viable addition to Individual Placement and Support (IPS), supporting recovery orientated services for people with the full range of mental disorders. They are currently an underdeveloped sector in the UK

    Dynamics of Simple Balancing Models with State Dependent Switching Control

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    Time-delayed control in a balancing problem may be a nonsmooth function for a variety of reasons. In this paper we study a simple model of the control of an inverted pendulum by either a connected movable cart or an applied torque for which the control is turned off when the pendulum is located within certain regions of phase space. Without applying a small angle approximation for deviations about the vertical position, we see structurally stable periodic orbits which may be attracting or repelling. Due to the nonsmooth nature of the control, these periodic orbits are born in various discontinuity-induced bifurcations. Also we show that a coincidence of switching events can produce complicated periodic and aperiodic solutions.Comment: 36 pages, 12 figure

    Consistency Conditions for Fundamentally Discrete Theories

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    The dynamics of physical theories is usually described by differential equations. Difference equations then appear mainly as an approximation which can be used for a numerical analysis. As such, they have to fulfill certain conditions to ensure that the numerical solutions can reliably be used as approximations to solutions of the differential equation. There are, however, also systems where a difference equation is deemed to be fundamental, mainly in the context of quantum gravity. Since difference equations in general are harder to solve analytically than differential equations, it can be helpful to introduce an approximating differential equation as a continuum approximation. In this paper implications of this change in view point are analyzed to derive the conditions that the difference equation should satisfy. The difference equation in such a situation cannot be chosen freely but must be derived from a fundamental theory. Thus, the conditions for a discrete formulation can be translated into conditions for acceptable quantizations. In the main example, loop quantum cosmology, we show that the conditions are restrictive and serve as a selection criterion among possible quantization choices.Comment: 33 page

    Bidirectional Modulation of Alcohol-Associated Memory Reconsolidation through Manipulation of Adrenergic Signaling.

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    Alcohol addiction is a problem of great societal concern, for which there is scope to improve current treatments. One potential new treatment for alcohol addiction is based on disrupting the reconsolidation of the maladaptive Pavlovian memories that can precipitate relapse to drug-seeking behavior. In alcohol self-administering rats, we investigated the effects of bidirectionally modulating adrenergic signaling on the strength of a Pavlovian cue-alcohol memory, using a behavioral procedure that isolates the specific contribution of one maladaptive Pavlovian memory to relapse, the acquisition of a new alcohol-seeking response for an alcohol-associated conditioned reinforcer. The β-adrenergic receptor antagonist propranolol, administered in conjunction with memory reactivation, persistently disrupted the memory that underlies the capacity of a previously alcohol-associated cue to act as a conditioned reinforcer. By contrast, enhancement of adrenergic signaling by administration of the adrenergic prodrug dipivefrin at reactivation increased the strength of the cue-alcohol memory and potentiated alcohol seeking. These data demonstrate the importance of adrenergic signaling in alcohol-associated memory reconsolidation, and suggest a pharmacological target for treatments aiming to prevent relapse through the disruption of maladaptive memories.This work was supported by a UK Medical Research Council Programme Grant (G1002231) to BJE and ALM and was conducted in the Behavioural and Clinical Neuroscience Institute (BCNI), an initiative jointly funded by the MRC and the Wellcome Trust. MJWS was supported by an MRC Doctoral Training Grant and the James Baird Fund at the Medical School of the University of Cambridge. ALM was partly supported by a BCNI lectureship and the Ferreras-Willetts Fellowship from Downing College, Cambridge.This is the author accepted manuscript. The final version is available from Nature Publishing Group via http://dx.doi.org/10.1038/npp.2015.24
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