1,388 research outputs found

    A comment on BCC crystalization in higher dimensions

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    The result that near the melting point three-dimensional crystals have an octahedronic structure is generalized to higher flat non compact dimensions

    Sequence Specific Motor Performance Gains after Memory Consolidation in Children and Adolescents

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    Memory consolidation for a trained sequence of finger opposition movements, in 9- and 12-year-old children, was recently found to be significantly less susceptible to interference by a subsequent training experience, compared to that of 17-year-olds. It was suggested that, in children, the experience of training on any sequence of finger movements may affect the performance of the sequence elements, component movements, rather than the sequence as a unit; the latter has been implicated in the learning of the task by adults. This hypothesis implied a possible childhood advantage in the ability to transfer the gains from a trained to the reversed, untrained, sequence of movements. Here we report the results of transfer tests undertaken to test this proposal in 9-, 12-, and 17-year-olds after training in the finger-to-thumb opposition sequence (FOS) learning task. Our results show that the performance gains in the trained sequence partially transferred from the left, trained hand, to the untrained hand at 48-hours after a single training session in the three age-groups tested. However, there was very little transfer of the gains from the trained to the untrained, reversed, sequence performed by either hand. The results indicate sequence specific post-training gains in FOS performance, as opposed to a general improvement in performance of the individual, component, movements that comprised both the trained and untrained sequences. These results do not support the proposal that the reduced susceptibility to interference, in children before adolescence, reflects a difference in movement syntax representation after training

    Analisis TIME Series Produksi dan Konsumsi Pangan Ubi Kayu dan Ubi Jalar di Sumatera Utara

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    Pangan merupakan kebutuhan yang sangat penting bagi kelangsungan hidup setiap orang. Untuk dapat mempertahankan ketahanan pangan, pemerintah melakukan diversifikasi pangan dengan mengkonsumsi umbi-umbian yaitu ubi kayu dan ubi jalar. Penelitian bertujuan untuk menganalisis produksi dan konsumsi pangan ubi kayu dan ubi jalar di Sumatera Utara. Data yang digunakan adalah data sekunder. Metode yang digunakan dalam penelitian ini adalah metode least square dengan trend yang linier. Hasil penelitian menunjukkan bahwa pada tahun 1996-2010 produksi serta produktivitas pangan ubi kayu dan ubi jalar mengalami keadaan yang fluktuatif namun mengarah kepada peningkatan yang dipengaruhi oleh luas panen. Konsumsi ubi kayu dan ubi jalar disepanjang tahun tersebut juga mengalami keadaan fluktuatif karena dipengaruhi oleh jumlah penduduk dan konsumsi terhadap bahan pangan lain. Hasil peramalan untuk tahun 2015-2025 produksi dan konsumsi pangan ubi kayu mengalami trend yang menaik, sedangkan untuk produksi dan konsumsi pangan ubi jalar, hanya produksi ubi jalar yang mengalami trend yang menaik

    Accelerated convergence to steady state by gradual far-field damping

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76495/1/AIAA-11054-168.pd

    Through the Lens of a Momentum Microscope: Viewing Light‐Induced Quantum Phenomena in 2D Materials

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    Van der Waals (vdW) materials at their 2D limit are diverse, flexible, and unique laboratories to study fundamental quantum phenomena and their future applications. Their novel properties rely on their pronounced Coulomb interactions, variety of crystal symmetries and spin-physics, and the ease of incorporation of different vdW materials to form sophisticated heterostructures. In particular, the excited state properties of many 2D semiconductors and semi-metals are relevant for their technological applications, particularly those that can be induced by light. In this paper, the recent advances made in studying out-of-equilibrium, light-induced, phenomena in these materials are reviewed using powerful, surface-sensitive, time-resolved photoemission-based techniques, with a particular emphasis on the emerging multi-dimensional photoemission spectroscopy technique of time-resolved momentum microscopy. The advances this technique has enabled in studying the nature and dynamics of occupied excited states in these materials are discussed. Then, the future research directions opened by these scientific and instrumental advancements are projected for studying the physics of 2D materials and the opportunities to engineer their band-structure and band-topology by laser fields

    Partisipasi Masyarakat Minangkabau Pada Implementasi Program Pariwisata Dalam Pemberdayaan Masyarakat Islam

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    Pada dasarnya Islam adalah agama permberdayaan sebagaimana dalam Al Quran surat Ar Ra’du ayat 11. Pemberdayaan merupakan proses pengembangan partisipasi, terutama dalam pengelolaan pariwisata berbasis masyarakat yang membutuhkan keterlibatan penuh masyarakat sehingga berdampak pada kesejahteraan. Adapun masalah yang akan diteliti adalah: Bagaimana partisipasi masyarakat pada implementasi program pariwisata dalam pemberdayaan masyarakat Islam?. Penelitian ini bertujuan untuk: Mendeskripsikan dimensi partisipasi masyarakat pada implementasi program pariwisata dalam pemberdayaan masyarakat Islam. Penelitian ini didesain menggunakan metode pendekatan kualitatif dengan jenis penelitian Studi Kasus. Teknik “porposive sampling” termasuk ke dalam nonprobality sampling yaitu pengambilan subjek kajian bergantung kepada peneliti melihat subjek tersebut. Partisipasi masyarakat dalam seluruh aktifitas program pariwisata dilihat pada dimensi, Decision Making, Implementations, Benefits dan Evaluation. Anggota masyarakat dalam pengelolaan pariwisata di Lubuk Nyarai berpartisipasi pada seluruh dimensi, sehingga memiliki dampak pada kesejahteraan sosial, budaya, lingkungan dan ekonomi. Hal ini menjadi acuan bagi pemerintah dalam pengelolaan pariwisata pada pemberdayaan masyarakat islam, dengan melibatkan seluruh anggota masyarakat pengelola dalam setiap dimensi partisipasi, serta memberikan kepercayaan kepada anggota masyarakat untuk dapat merefleksikan aksinya pada tindakan kolektif melalui pelaksanaan kegiatan bersama

    Attachment-based family therapy for adolescents with suicidal ideation: a randomized controlled trial.

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    OBJECTIVE: To evaluate whether Attachment-Based Family Therapy (ABFT) is more effective than Enhanced Usual Care (EUC) for reducing suicidal ideation and depressive symptoms in adolescents. METHOD: This was a randomized controlled trial of suicidal adolescents between the ages of 12 and 17, identified in primary care and emergency departments. Of 341 adolescents screened, 66 (70% African American) entered the study for 3 months of treatment. Assessment occurred at baseline, 6 weeks, 12 weeks, and 24 weeks. ABFT consisted of individual and family meetings, and EUC consisted of a facilitated referral to other providers. All participants received weekly monitoring and access to a 24-hour crisis phone. Trajectory of change and clinical recovery were measured for suicidal ideation and depressive symptoms. RESULTS: Using intent to treat, patients in ABFT demonstrated significantly greater rates of change on self-reported suicidal ideation at post-treatment evaluation, and benefits were maintained at follow-up, with a strong overall effect size (ES = 0.97). Between-group differences were similar on clinician ratings. Significantly more patients in ABFT met criteria for clinical recovery on suicidal ideation post-treatment (87%; 95% confidence interval [CI] = 74.6-99.6) than patients in EUC (51.7%; 95% CI = 32.4-54.32). Benefits were maintained at follow-up (ABFT, 70%; 95% CI = 52.6-87.4; EUC 34.6%; 95% CI = 15.6-54.2; odds ratio = 4.41). Patterns of depressive symptoms over time were similar, as were results for a subsample of adolescents with diagnosed depression. Retention in ABFT was higher than in EUC (mean = 9.7 versus 2.9). CONCLUSIONS: ABFT is more efficacious than EUC in reducing suicidal ideation and depressive symptoms in adolescents. Additional research is warranted to confirm treatment efficacy and to test the proposed mechanism of change (the Family Safety Net Study).Clinical Trial Registry Information: Preventing Youth Suicide in Primary Care: A Family Model, URL: http://www.clinicaltrials.gov, unique identifier: NCT00604097

    Spherically symmetric relativistic MHD simulations of pulsar wind nebulae in supernova remnants

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    Pulsars, formed during supernova explosions, are known to be sources of relativistic magnetized winds whose interaction with the expanding supernova remnants (SNRs) gives rise to a pulsar wind nebula (PWN). We present spherically symmetric relativistic magnetohydrodynamics (RMHD) simulations of the interaction of a pulsar wind with the surrounding SNR, both in particle and magnetically dominated regimes. As shown by previous simulations, the evolution can be divided in three phases: free expansion, a transient phase characterized by the compression and reverberation of the reverse shock, and a final Sedov expansion. The evolution of the contact discontinuity between the PWN and the SNR (and consequently of the SNR itself) is almost independent of the magnetization of the nebula as long as the total (magnetic plus particle) energy is the same. However, a different behaviour of the PWN internal structure is observable during the compression-reverberation phase, depending on the degree of magnetization=2E The simulations were performed using the third order conservative scheme by Del Zanna et al. (2003).Comment: 11 pages, Latex, 22 Encapsulated PostScript figures, accepted f or publication on A&
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