429 research outputs found

    It's all about timing : an electrophysiological examination of feedback-based learning with immediate and delayed feedback

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    Feedback regarding an individual's action can occur immediately or with a temporal delay. Processing of feedback that varies in its delivery time is proposed to engage different brain mechanisms. fMRI data implicate the striatum in the processing of immediate feedback, and the medial temporal lobe (MTL) in the processing of delayed feedback. The present study offers an electrophysiological examination of feedback processing in the context of timing, by studying the effects of feedback timing on the feedback-related negativity (FRN), a product of the midbrain dopamine system, and elucidating whether the N170 ERP component could capture MTL activation associated with the processing of delayed feedback. Participants completed a word-object paired association learning task; they received feedback 500 ms (immediate feedback condition) following a button press during the learning of two sets of 14 items, and at a delay of 6500 ms (delayed feedback condition) during the learning of the other two sets. The results indicated that while learning outcomes did not differ under the two timing conditions, Event Related Potential (ERPs) pointed to differential activation of the examined ERP components. FRN amplitude was found to be larger following the immediate feedback condition when compared with the delayed feedback condition, and sensitive to valence and learning only under the immediate feedback condition. Additionally, the amplitude of the N170 was found larger following the delayed feedback condition when compared with the immediate feedback condition. Taken together, the findings of the present study support the contention that the processing of delayed feedback involves a shift away from midbrain dopamine activation to the recruitment of the MTL

    Giant radiation heat transfer through the micron gaps

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    Near-field heat transfer between two closely spaced radiating media can exceed in orders radiation through the interface of a single black body. This effect is caused by exponentially decaying (evanescent) waves which form the photon tunnel between two transparent boundaries. However, in the mid-infrared range it holds when the gap between two media is as small as few tens of nanometers. We propose a new paradigm of the radiation heat transfer which makes possible the strong photon tunneling for micron thick gaps. For it the air gap between two media should be modified, so that evanescent waves are transformed inside it into propagating ones. This modification is achievable using a metamaterial so that the direct thermal conductance through the metamaterial is practically absent and the photovoltaic conversion of the transferred heat is not altered by the metamaterial.Comment: 4 pages, 3 figure

    The Prevalence of Burnout and Musculoskeletal Disorders in Physician Associates Students

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    Physician Associate, formerly known as Physician Assistant, (PA) is a growing occupation that originated in the 1960s. Previous research focused on the prevalence of musculoskeletal disorders and burnout in nursing, nursing students, PA, and ubiquitously assumed among many healthcare professionals; however, burnout and musculoskeletal disorders are under-researched in PA students. PURPOSE: To investigate the prevalence of burnout and musculoskeletal disorders in Physician Associate students. METHODS: This study was conducted at a private university in Florida. Twelve PA students participated in the study, nine females and three males (mean age 26.3 ± 1.8 years; mean height 166.6 ± 7.6 cm; mean weight 67.9 ± 14.0 kg). Eleven PA students were in their fifth clinical rotation and one in their sixth. Maslach Burnout Inventory Human Services Survey for Medical Personnel (MBI) and the Canadian Medical History Checklist: Symptoms Survey for Work-Related Musculoskeletal Disorders (WMSDs) were used. In the MBI questionnaire, burnout was quantified by three subcomponents: emotional exhaustion (EE), depersonalization (DP), and personal accomplishment (PA). The WMSDs questionnaire measured the degree of acute pain in the neck, shoulder, elbow, wrist, hand, upper back, lower back, and foot. Participants filled out the two questionnaires in one session and the data were collected and analyzed. RESULTS: In the MBI survey, 84% of participants reported high to moderate EE (67% high, 17% moderate, and 17% low); 58.3% of participants reported high to moderate DP (33.3% high, 25% moderate, and 41.7% low); 66.6% of participants reported high to moderate PA (33.3% high, 33.3% moderate, and 33.3% low). In the WMSDs questionnaire, 75% of participants reported having pain or discomfort, in the last year, caused by their job that lasted two days or more in the neck, shoulder, and upper back, whereas 58% reported lower back pain or discomfort. Out of all participants reporting pain or discomfort, several participants reported that pain worsened while working, 67.7% reported for the neck; 44.4% for the shoulder; 67.7% for the upper back; and 57.1% for lower back pain. CONCLUSION: The results of the questionnaires indicated a high prevalence of burnout and musculoskeletal disorders in PA students. Physician Associate programs should include educational content emphasizing techniques to minimize burnout and reduce the prevalence of musculoskeletal disorders. Further research is needed to identify the influence of physical activity and relaxation techniques on burnout levels and the prevalence of musculoskeletal disorders in PA students

    INO80 and Îł-H2AX Interaction Links ATP-Dependent Chromatin Remodeling to DNA Damage Repair

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    AbstractWhile the role of ATP-dependent chromatin remodeling in transcription is well established, a link between chromatin remodeling and DNA repair has remained elusive. We have found that the evolutionarily conserved INO80 chromatin remodeling complex directly participates in the repair of a double-strand break (DSB) in yeast. The INO80 complex is recruited to a HO endonuclease-induced DSB through a specific interaction with the DNA damage-induced phosphorylated histone H2A (Îł-H2AX). This interaction requires Nhp10, an HMG-like subunit of the INO80 complex. The loss of Nhp10 or Îł-H2AX results in reduced INO80 recruitment to the DSB. Finally, components of the INO80 complex show synthetic genetic interactions with the RAD52 DNA repair pathway, the main pathway for DSB repair in yeast. Our findings reveal a new role of ATP-dependent chromatin remodeling in nuclear processes and suggest that an ATP-dependent chromatin remodeling complex can read a DNA repair histone code

    A Transgenic Model Reveals the Role of Klotho in Pancreatic Cancer Development and Paves the Way for New Klotho-Based Therapy

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    Klotho; Càncer de pàncrees; Supressor del tumorKlotho; Cáncer de páncreas; Supresor de tumorKlotho; Pancreatic cancer; Tumor suppressorKlotho is an anti-aging transmembrane protein, which can be shed and can function as a hormone. Accumulating data indicate that klotho is a tumor suppressor in a wide array of malignancies, and designate the subdomain KL1 as the active region of the protein towards this activity. We aimed to study the role of klotho as a tumor suppressor in pancreatic ductal adenocarcinoma (PDAC). Bioinformatics analyses of The Cancer Genome Atlas (TCGA) datasets revealed a correlation between the survival of PDAC patients, levels of klotho expression, and DNA methylation, and demonstrated a unique hypermethylation pattern of klotho in pancreatic tumors. The in vivo effects of klotho and KL1 were examined using three mouse models. Employing a novel genetic model, combining pancreatic klotho knockdown with a mutation in Kras, the lack of klotho contributed to PDAC generation and decreased mousece survival. In a xenograft model, administration of viral particles carrying sKL, a spliced klotho isoform containing the KL1 domain, inhibited pancreatic tumors. Lastly, treatment with soluble sKL prolonged survival of Pdx1-Cre; KrasG12D/+;Trp53R172H/+ (KPC) mice, a model known to recapitulate human PDAC. In conclusion, this study provides evidence that klotho is a tumor suppressor in PDAC. Furthermore, these data suggest that the levels of klotho expression and DNA methylation could have prognostic value in PDAC patients, and that administration of exogenous sKL may serve as a novel therapeutic strategy to treat PDAC.This project was funded by the The Sami and Tova Sagol Foundation for the Study of Aging, the Margaret Stultz foundation for Pancreatic Cancer Research, the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; Ministerio de Ciencia e Innovación ‘Proyectos I+D+I 2019, to M.C., (grant number PID2019-104034RB-I00) and by the TASMC excellence fund. to I.W

    Stationary solutions of the one-dimensional nonlinear Schroedinger equation: II. Case of attractive nonlinearity

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    All stationary solutions to the one-dimensional nonlinear Schroedinger equation under box or periodic boundary conditions are presented in analytic form for the case of attractive nonlinearity. A companion paper has treated the repulsive case. Our solutions take the form of bounded, quantized, stationary trains of bright solitons. Among them are two uniquely nonlinear classes of nodeless solutions, whose properties and physical meaning are discussed in detail. The full set of symmetry-breaking stationary states are described by the CnC_{n} character tables from the theory of point groups. We make experimental predictions for the Bose-Einstein condensate and show that, though these are the analog of some of the simplest problems in linear quantum mechanics, nonlinearity introduces new and surprising phenomena.Comment: 11 pages, 9 figures -- revised versio

    Exact closed form analytical solutions for vibrating cavities

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    For one-dimensional vibrating cavity systems appearing in the standard illustration of the dynamical Casimir effect, we propose an approach to the construction of exact closed-form solutions. As new results, we obtain solutions that are given for arbitrary frequencies, amplitudes and time regions. In a broad range of parameters, a vibrating cavity model exhibits the general property of exponential instability. Marginal behavior of the system manifests in a power-like growth of radiated energy.Comment: 17 pages, 7 figure

    Stability of stationary states in the cubic nonlinear Schroedinger equation: applications to the Bose-Einstein condensate

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    The stability properties and perturbation-induced dynamics of the full set of stationary states of the nonlinear Schroedinger equation are investigated numerically in two physical contexts: periodic solutions on a ring and confinement by a harmonic potential. Our comprehensive studies emphasize physical interpretations useful to experimentalists. Perturbation by stochastic white noise, phase engineering, and higher order nonlinearity are considered. We treat both attractive and repulsive nonlinearity and illustrate the soliton-train nature of the stationary states.Comment: 9 pages, 11 figure
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