184 research outputs found

    Linear theory and violent relaxation in long-range systems: a test case

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    In this article, several aspects of the dynamics of a toy model for longrange Hamiltonian systems are tackled focusing on linearly unstable unmagnetized (i.e. force-free) cold equilibria states of the Hamiltonian Mean Field (HMF). For special cases, exact finite-N linear growth rates have been exhibited, including, in some spatially inhomogeneous case, finite-N corrections. A random matrix approach is then proposed to estimate the finite-N growth rate for some random initial states. Within the continuous, N→∞N \rightarrow \infty, approach, the growth rates are finally derived without restricting to spatially homogeneous cases. All the numerical simulations show a very good agreement with the different theoretical predictions. Then, these linear results are used to discuss the large-time nonlinear evolution. A simple criterion is proposed to measure the ability of the system to undergo a violent relaxation that transports it in the vicinity of the equilibrium state within some linear e-folding times

    Epidemic space

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    The aim of this article is to highlight the importance of 'spatiality' in understanding the materialization of risk society and cultivation of risk sensibilities. More specifically it provides a cultural analysis of pathogen virulence (as a social phenomenon) by means of tracing and mapping the spatial flows that operate in the uncharted zones between the microphysics of infection and the macrophysics of epidemics. It will be argued that epidemic space consists of three types of forces: the vector, the index and the vortex. It will draw on Latour's Actor Network Theory to argue that epidemic space is geared towards instability when the vortex (of expanding associations and concerns) displaces the index (of finding a single cause)

    Anthroposophic therapy for chronic depression: a four-year prospective cohort study

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    BACKGROUND: Depressive disorders are common, cause considerable disability, and do not always respond to standard therapy (psychotherapy, antidepressants). Anthroposophic treatment for depression differs from ordinary treatment in the use of artistic and physical therapies and special medication. We studied clinical outcomes of anthroposophic therapy for depression. METHODS: 97 outpatients from 42 medical practices in Germany participated in a prospective cohort study. Patients were aged 20–69 years and were referred to anthroposophic therapies (art, eurythmy movement exercises, or rhythmical massage) or started physician-provided anthroposophic therapy (counselling, medication) for depression: depressed mood, at least two of six further depressive symptoms, minimum duration six months, Center for Epidemiological Studies Depression Scale, German version (CES-D, range 0–60 points) of at least 24 points. Outcomes were CES-D (primary outcome) and SF-36 after 3, 6, 12, 18, 24, and 48 months. Data were collected from July 1998 to March 2005. RESULTS: Median number of art/eurythmy/massage sessions was 14 (interquartile range 12–22), median therapy duration was 137 (91–212) days. All outcomes improved significantly between baseline and all subsequent follow-ups. Improvements from baseline to 12 months were: CES-D from mean (standard deviation) 34.77 (8.21) to 19.55 (13.12) (p < 0.001), SF-36 Mental Component Summary from 26.11 (7.98) to 39.15 (12.08) (p < 0.001), and SF-36 Physical Component Summary from 43.78 (9.46) to 48.79 (9.00) (p < 0.001). All these improvements were maintained until last follow-up. At 12-month follow-up and later, 52%–56% of evaluable patients (35%–42% of all patients) were improved by at least 50% of baseline CES-D scores. CES-D improved similarly in patients not using antidepressants or psychotherapy during the first six study months (55% of patients). CONCLUSION: In outpatients with chronic depression, anthroposophic therapies were followed by long-term clinical improvement. Although the pre-post design of the present study does not allow for conclusions about comparative effectiveness, study findings suggest that the anthroposophic approach, with its recourse to non-verbal and artistic exercising therapies can be useful for patients motivated for such therapies

    A qualitative emancipatory inquiry into relationships between people with mental disorders and health professionals

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    Introduction: A therapeutic alliance with people is essential for the efficacy of treatments. However, the traditional paternalistic values of the Mediterranean society may be incompatible with patient autonomy. Aim: To explore the therapeutic relationship from the perspective of people diagnosed with mental disorders with health professionals, including nurses. Methods: This emancipatory research was performed through focus groups, with people with mental disorders who had a variety of diagnoses and experiences of acute and community‐based mental health services and other healthcare services. Data were analysed using the content analysis method. Results: Four main themes emerged: stereotypes and prejudice; quality of interactions and treatment; emotional and behavioural impacts; and demands. Discussion: According to the participants' descriptions, health professionals are not exempt from prejudice against persons with psychiatric diagnoses. They reported experiencing abuse of power, malpractice, and overmedication. Thus, in the Mediterranean culture, professional attitudes may represent a barrier for an appropriate therapeutic alliance, and people with mental disorders do not feel involved in making decisions about their health. Implications for practice: Knowing how people with mental disorders perceive their interactions with health professionals and the effects is necessary to move the care model towards more symmetric relationships that facilitate a therapeutic alliance

    Promoting Client Participation and Constructing Decisions in Mental Health Rehabilitation Meetings

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    The chapter analyzes practices by which support workers promote client participation in mental health rehabilitation meetings at the Clubhouse. While promoting client participation, the support workers also need to ascertain that at least some decisions get constructed during the meetings. This combination of goals—promoting participation and constructing decisions—leads to a series of dilemmatic practices, the dynamics of which the chapter focuses on analyzing. The support workers may treat clients’ turns retrospectively as proposals, even if the status of these turns as such is ambiguous. In the face of a lack of recipient uptake, the support workers may remind the clients about their epistemic access to the content of the proposal or pursue their agreement or commitment to the idea. These practices involve the support workers carrying primary responsibility over the unfolding of interaction, which is argued to compromise the jointness of the decision-making outcome.The chapter analyzes practices by which support workers promote client participation in mental health rehabilitation meetings at the Clubhouse. While promoting client participation, the support workers also need to ascertain that at least some decisions get constructed during the meetings. This combination of goals—promoting participation and constructing decisions—leads to a series of dilemmatic practices, the dynamics of which the chapter focuses on analyzing. The support workers may treat clients’ turns retrospectively as proposals, even if the status of these turns as such is ambiguous. In the face of a lack of recipient uptake, the support workers may remind the clients about their epistemic access to the content of the proposal or pursue their agreement or commitment to the idea. These practices involve the support workers carrying primary responsibility over the unfolding of interaction, which is argued to compromise the jointness of the decision-making outcome.Peer reviewe

    The benefit of symbols: monkeys show linear, human-like, accuracy when using symbols to represent scalar value

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    When humans and animals estimate numbers of items, their error rate is proportional to the number. To date, however, only humans show the capacity to represent large numbers symbolically, which endows them with increased precision, especially for large numbers, and with tools for manipulating numbers. This ability depends critically on our capacity to acquire and represent explicit symbols. Here we show that when rhesus monkeys are trained to use an explicit symbol system, they too show more precise, and linear, scaling than they do using a one-to-one corresponding numerosity representation. We also found that when taught two different types of representations for reward amount, the monkeys systematically undervalued the less precise representation. The results indicate that monkeys, like humans, can learn alternative mechanisms for representing a single value scale and that performance variability and relative value depend on the distinguishability of each representation

    Towards a resolution of some outstanding issues in transitive research: an empirical test on middle childhood

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    Transitive Inference (deduce B > D from B > C and C > D) can help us to understand other areas of sociocognitive development. Across three experiments, learning, memory, and the validity of two transitive paradigms were investigated. In Experiment 1 (N = 121), 7-year-olds completed a three-term nontraining task or a five-term task requiring extensive-training. Performance was superior on the three-term task. Experiment 2 presented 5–10-year-olds with a new five-term task, increasing learning opportunities without lengthening training (N = 71). Inferences improved, suggesting children can learn five-term series rapidly. Regarding memory, the minor (CD) premise was the best predictor of BD-inferential performance in both task-types. However, tasks exhibited different profiles according to associations between the major (BC) premise and BD inference, correlations between the premises, and the role of age. Experiment 3 (N = 227) helped rule out the possible objection that the above findings simply stemmed from three-term tasks with real objects being easier to solve than computer-tasks. It also confirmed that, unlike for five-term task (Experiments 1 & 2), inferences on three-term tasks improve with age, whether the age range is wide (Experiment 3) or narrow (Experiment 2). I conclude that the tasks indexed different routes within a dual-process conception of transitive reasoning: The five-term tasks indexes Type 1 (associative) processing, and the three-term task indexes Type 2 (analytic) processing. As well as demonstrating that both tasks are perfectly valid, these findings open up opportunities to use transitive tasks for educability, to investigate the role of transitivity in other domains of reasoning, and potentially to benefit the lived experiences of persons with developmental issues
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