17,457 research outputs found

    Role of the exchange and correlation potential into calculating the x-ray absorption spectra of half-metallic alloys: the case of Mn and Cu K-edge XANES in Cu2_2MnM (M = Al, Sn, In) Heusler alloys

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    This work reports a theoretical study of the x-ray absorption near-edge structure spectra at both the Cu and the Mn K-edge in several Cu2_2MnM (M= Al, Sn and In) Heusler alloys. Our results show that {\it ab-initio} single-channel multiple-scattering calculations are able of reproducing the experimental spectra. Moreover, an extensive discussion is presented concerning the role of the final state potential needed to reproduce the experimental data of these half-metallic alloys. In particular, the effects of the cluster-size and of the exchange and correlation potential needed in reproducing all the experimental XANES features are discussed.Comment: 15 pages, 5 figure

    Sensory substitution for space gloves and for space robots

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    Sensory substitution systems for space applications are described. Physical sensors replace missing human receptors and feed information to the interpretive centers of a different sense. The brain is plastic enough so that, with training, the subject localizes the input as if it were received through the missing receptors. Astronauts have difficulty feeling objects through space suit gloves because of their thickness and because of the 4.3 psi pressure difference. Miniature force sensors on the glove palm drive an electrotactile belt around the waist, thus augmenting the missing tactile sensation. A proposed teleoperator system with telepresence for a space robot would incorporate teleproprioception and a force sensor/electrotactile belt sensory substitution system for teletouch

    The use and efficacy of question type and an attentive interviewing style in adult rape interviews

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    Police interviewers find the investigation of sexual crimes ‘technically difficult’ and ‘stressful’ to conduct by having to make sense of very powerful and painful emotions. In addition, such interviews often contain inappropriate as opposed to appropriate questions and interviewers often find it difficult to be ‘attentive’ to the specific needs of victims. Through the analysis of interviews with adult rape victims (N = 25) in England, we wanted to establish whether the ‘quantity’ and ‘quality’ of investigation relevant information (IRI) obtained would be impacted as a function of different question typologies (e.g. appropriate versus inappropriate), and overall interviewer attentiveness. We hypothesised that: (i) more inappropriate questions would be asked compared to appropriate questions; (ii) responses to appropriate questions would contain more items of IRI than responses to inappropriate questions; (iii) attentive interviews would contain more appropriate questions than non-attentive interviews, and; (iv) attentive interviews would contain more IRI than non-attentive interviews. Results found that interviewers asked significantly more appropriate questions that elicited significantly more items of IRI. However, there were no significant differences in the number of appropriate questions asked or the impact on the amount of IRI obtained between interviews as a function of interviewer attentiveness. Implications for practice are discussed

    Simple manipulation of a microwave dressed-state ion qubit

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    Many schemes for implementing quantum information processing require that the atomic states used have a non-zero magnetic moment, however such magnetically sensitive states of an atom are vulnerable to decoherence due to fluctuating magnetic fields. Dressing an atom with an external field is a powerful method of reducing such decoherence [N. Timoney et al., Nature 476, 185], even if the states being dressed are strongly coupled to the environment. We introduce an experimentally simpler method of manipulating such a dressed-state qubit, which allows the implementation of general rotations of the qubit, and demonstrate this method using a trapped ytterbium ion

    Toxoplasma gondii: An Underestimated Threat?

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    Traditionally, the protozoan parasite Toxoplasma gondii has been thought of as relevant to public health primarily within the context of congenital toxoplasmosis or postnatally acquired disease in immunocompromised patients. However, latent T. gondii infection has been increasingly associated with a wide variety of neuropsychiatric disorders and, more recently, causal frameworks for these epidemiological associations have been proposed. We present assimilated evidence on the associations between T. gondii and various human neuropsychiatric disorders and outline how these may be explained within a unifying causal framework. We argue that the occult effects of latent T. gondii infection likely outweigh the recognised overt morbidity caused by toxoplasmosis, substantially raising the public health importance of this parasite. [Abstract copyright: Copyright © 2020 Elsevier Ltd. All rights reserved.

    Detyrosination of alpha tubulin does not stabilize microtubules in vivo.

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    The relationship between alpha tubulin detyrosination and microtubule (MT) stability was examined directly in cultured fibroblasts by experimentally converting the predominantly tyrosinated MT array to a detyrosinated (Glu) array and then assaying MT stability. MTs in mouse Swiss 3T3 cells displayed an increase in Glu immunostaining fluorescence approximately 1 h after microinjecting antibodies to the tyrosinating enzyme, tubulin tyrosine ligase. Detyrosination progressed to virtual completion after 12 h and persisted for 30-35 h before tyrosinated subunits within MTs were again detected. The stability of these experimentally detyrosinated MTs was tested by first injecting either biotinylated or Xrhodamine-labeled tubulin and then measuring bulk turnover by hapten-mediated immunocytochemistry or fluorescence recovery after photobleaching, respectively. By both methods, turnover was found to be similarly rapid, possessing a half time of approximately 3 min. As a final test of MT stability, the level of acetylated tubulin staining in antibody-injected cells was compared with that observed in adjacent, uninjected cells and also with the staining observed in cells whose MTs had been stabilized with taxol. Although intense Glu staining was observed in both injected and taxol-treated cells, increased acetylated tubulin staining was observed only in the taxol-stabilized MTs, indicating that the MTs were not stabilized by detyrosination. Together, these results demonstrated clearly that detyrosination does not directly confer stability on MTs. Therefore, the stable MTs observed in these and other cell lines must have arisen by another mechanism, and may have become posttranslationally modified after their stabilization
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