1,573 research outputs found

    Simulation of a vacuum phototriode with SIMION 3D

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    An electron-optic model of a 26 mm diameter vacuum phototriode (VPT) photodetector was developed using SIMION 3D software extended by additional code to simulate secondary emission at the dynode. The predictions of the variation of gain with magnetic field for mesh anodes with 100, 40 and 7 lines per mm and fields from 0 and 4 T are presented. The predicted time development of the signal at 0 T is presented and compared with experimental data obtained by illuminating a production VPT for the electromagnetic endcap calorimeter of CMS with 60 ps laser pulses at a wavelength of 435 nm

    Identification. The missing link between joint attention and imitation

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    In this paper we outline our hypothesis that human intersubjective engagement entails identifying with other people. We tested a prediction derived from this hypothesis that concerned the relation between a component of joint attention and a specific form of imitation. The empirical investigation involved “blind” ratings of videotapes from a recent study in which we tested matched children with and without autism for their propensity to imitate the self-/other-orientated aspects of another person's actions. The results were in keeping with three a priori predictions, as follows: (a) children with autism contrasted with control participants in spending more time looking at the objects acted upon and less time looking at the tester; (b) participants with autism showed fewer “sharing” looks toward the tester, and although they also showed fewer “checking” and “orientating” looks, they were specifically less likely to show any sharing looks; and, critically, (c) within each group, individual differences in sharing looks (only) were associated with imitation of self–other orientation. We suggest that the propensity to adopt the bodily anchored psychological stance of another person is essential to certain forms of joint attention and imitation, and that a weak tendency to identify with others is pivotal for the developmental psychopathology of autism

    A controlled study of hostile-helpless states of mind among borderline and dysthymic women

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    The aim of this study was to determine whether women with borderline personality disorder (BPD) are more likely than those with dysthymia to manifest contradictory Hostile-Helpless (HH) states of mind. A reliable rater blind to diagnosis evaluated features of such mental representations in transcripts of Adult Attachment Interviews from 12 women with BPD and 11 women with dysthymia of similar socioeconomic status (SES), all awaiting psychotherapy. In keeping with three hierarchical (non-independent) a priori predictions regarding the mental representations of women with BPD, the results were that (a) all those with BPD, compared with half the group with dysthymia, displayed HH states of mind; (b) those with BPD manifested a significantly higher frequency of globally devaluing representations; and (c) they exhibited a strong trend toward identifying with the devalued hostile caregiver (58% BPD vs. 18% dysthymic). In addition, significantly more BPD than dysthymic patients made reference to controlling behavior towards attachment figures in childhood. These findings offer fresh insights into the nature of BPD and extend previous evidence concerning affected individuals' patterns of thinking and feeling about childhood attachment figures

    Understanding self and other

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    Collaborative competence in dialogue: : Pragmatic language impairment as a window onto the psychopathology of autism

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    Background: Pragmatic language, including conversational ability, can be difficult for people with autism. Difficulties with dialogue may reflect impairment in interpersonal engagement more than general language ability. Method: We investigated conversational abilities among children and adolescents with and without autism (n = 18 per group) matched for language proficiency and productivity. Videotaped conversations from the Autism Diagnostic Observational Schedule (ADOS, Lord, Rutter, DiLavore, & Risi, 2001) were rated according to the Collaborative Competence in Dialogue (CCD) scale featuring six verbal and non-verbal ‘cues’ that conversational partners use to sustain dialogue. Results: Participants with autism produced significantly fewer ‘typical’ communicative cues and more cues rated as intermittent or rote/stereotyped, even when non-verbal items (gaze) were removed from consideration. Within the autism group, competence in dialogue was not correlated with ‘general’ language ability, but was correlated with a measure of pragmatic ability. Conclusions: Difficulties with collaboration in dialogue may mirror the intermittent or incomplete interpersonal engagement of children with autism. Implications: Assessment of language ability in autism should include observation in unstructured social settings

    Treatment for femoroacetabular impingement : a qualitative method for exploring equipoise amongst hip arthroscopy surgeons

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    R : URGENT The published literature suggests uncertainty about whether operative or nonoperative treatments are best for femoroacetabular impingement (FAI). Without the same level of uncertainty (equipoise) amongst surgeons, a RCT will be challenging. A qualitative study was conducted to explore the level of equipoise amongst arthroscopic FAI surgeons. In phase 1, 14 hip arthroscopy surgeons were interviewed and asked to make treatment decisions based on real life cases that included actively recruiting patients to a theoretical RCT. In phase 2, 9 hip arthroscopy hip surgeons participating in a pilot RCT were interviewed about their experiences so far of taking part in a pilot RCT. Five surgeons took part in both phase 1 and 2. Sixteen (89%) surgeons believed that they were in equipoise and that a RCT was required to generate superior scientific evidence and guidelines for the care. Despite this 5 (36%) surgeons showed a lack of active clinical equipoise when faced with real life case scenarios or discussing involvement with a pilot RCT. Some of the reasons behind surgeons’ lack of equipoise, ranged from lack of belief in the FAI pathology, to personal enthusiasm and gut instinct about the efficacy of surgery on one hand; but conservatism on the other. Although many would like a RCT to guide care, there may be particular challenges amongst this same population when actively recruiting patients to a RCT. Qualitative methodology can be used to help design surgical RCTs and address any subsequent difficulties with recruitment

    Foundation of Statistical Mechanics under experimentally realistic conditions

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    We demonstrate the equilibration of isolated macroscopic quantum systems, prepared in non-equilibrium mixed states with significant population of many energy levels, and observed by instruments with a reasonably bound working range compared to the resolution limit. Both properties are fulfilled under many, if not all, experimentally realistic conditions. At equilibrium, the predictions and limitations of Statistical Mechanics are recovered.Comment: Accepted in Phys. Rev. Let

    Non-parametric comparison of histogrammed two-dimensional data distributions using the Energy Test

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    When monitoring complex experiments, comparison is often made between regularly acquired histograms of data and reference histograms which represent the ideal state of the equipment. With the larger HEP experiments now ramping up, there is a need for automation of this task since the volume of comparisons could overwhelm human operators. However, the two-dimensional histogram comparison tools available in ROOT have been noted in the past to exhibit shortcomings. We discuss a newer comparison test for two-dimensional histograms, based on the Energy Test of Aslan and Zech, which provides more conclusive discrimination between histograms of data coming from different distributions than methods provided in a recent ROOT release.The Science and Technology Facilities Council, U

    Thin resonant structures for angle and polarization independent microwave absorption

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    Copyright © 2009 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Applied Physics Letters 94 (2009) and may be found at http://link.aip.org/link/?APPLAB/94/041913/1We present a microwave absorbing structure comprised of an array of subwavelength radius copper disks, closely spaced from a ground plane by a low loss dielectric. Experiments and accompanying modeling demonstrate that this structure supports electromagnetic standing wave resonances associated with a cylindrical cavity formed by the volume immediately beneath each metal disk. Microwave absorption on resonance of these modes, at wavelengths much greater than the thickness of the structure, is dictated almost entirely by the radius of the disk and permittivity of the dielectric, being largely independent of the incident angle and polarization

    Efficient computation of hashes

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    The sequential computation of hashes at the core of many distributed storage systems and found, for example, in grid services can hinder efficiency in service quality and even pose security challenges that can only be addressed by the use of parallel hash tree modes. The main contributions of this paper are, first, the identification of several efficiency and security challenges posed by the use of sequential hash computation based on the Merkle-Damgard engine. In addition, alternatives for the parallel computation of hash trees are discussed, and a prototype for a new parallel implementation of the Keccak function, the SHA-3 winner, is introduced
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