1,033 research outputs found

    Quantum revival for elastic waves in thin plate

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    Quantum revival is described as the time-periodic reconstruction of a wave packet initially localized in space and time. This effect is expected in finite-size systems which exhibits commensurable discrete spectrum such as the infinite quantum well. Here, we report on the experimental observation of full and fractional quantum revival for classical waves in a two dimensional cavity. We consider flexural waves propagating in thin plates, as their quadratic dispersion at low frequencies mimics the dispersion relation of quantum systems governed by Schr\"{o}dinger equation. Time-dependent excitation and measurement are performed at ultrasonic frequencies and reveal a periodic reconstruction of the initial elastic wave packet.Comment: submitted to the special issue of EPJ ST in honor of scientific legacy of Roger Maynar

    Infusion of technology in the classroom : implementing an instructional technology matrix to help teachers

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    Teachers have become acquainted with integrating technology (IT) and embedding it in lesson plans. However, the workshops given have typically focussed on hardware and software functions, rather than lesson planning. This research examined the use of an instructional technology matrix (ITM) to create lesson plans by applying Jonassen and Tessmer's constructivist taxonomy and ASSURE model with the hypothesis that an ITM would enhance teachers' abilities to use and create IT lessons. A workshop was given to undergraduate students in Education who were enrolled in an ITC summer class. A pre and post-questionnaire measuring their IT use and perceptions were given. As an end product of the workshop, the participants were invited to produce a lesson plan integrating the ITM. Further, two independent evaluators were asked to evaluate if the ITM was suited to teachers' needs in most educational reform plans. The research deals with two questions: (a) Is there a difference between the teacher's approach and the reform's project-oriented approach? (b) Could the elaboration of an instructional technology matrix for teachers (ITM), demonstrating the use of different level of cognitive learning, become an influential factor in IT lesson planning? Comments regarding the results of the ITM workshop as well as suggestions for further research are discussed. The research concludes that not enough classes and workshops are given to train efficient and effective teachers to use ITC in an educational environment and the ITM did not have a significant impact on their attitudes toward lesson planning

    L'hostilité et le risque suicidaire chez les femmes incarcérées

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    Medicaid spending burden among beneficiaries with treatment-resistant depression.

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    AIM: To evaluate Medicaid spending and healthcare resource utilization (HRU) in treatment-resistant depression (TRD). MATERIALS & METHODS: TRD beneficiaries were identified from Medicaid claims databases (January 2010-March 2017) and matched 1:1 with major depressive disorder (MDD) beneficiaries without TRD (non-TRD-MDD) and randomly selected patients without MDD (non-MDD). Differences in HRU and per-patient-per-year costs were reported in incidence rate ratios (IRRs) and cost differences (CDs), respectively. RESULTS: TRD beneficiaries had higher HRU than 1:1 matched non-TRD-MDD (e.g., inpatient visits: IRR = 1.41) and non-MDD beneficiaries (N = 14,710 per cohort; e.g., inpatient visits: IRR = 3.42, p \u3c 0.01). TRD beneficiaries incurred greater costs versus non-TRD-MDD (CD = US4382)andnonMDDbeneficiaries(CD=US4382) and non-MDD beneficiaries (CD = US8294; p \u3c 0.05). CONCLUSION: TRD is associated with higher HRU and costs versus non-TRD-MDD and non-MDD. TRD poses a significant burden to Medicaid

    Laboratory measurements of electrostatic solitary structures generated by electron beam injection

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    Electrostatic solitary structures are generated by injection of a suprathermal electron beam parallel to the magnetic field in a laboratory plasma. Electric microprobes with tips smaller than the Debye length (λDe\lambda_{De}) enabled the measurement of positive potential pulses with half-widths 4 to 25λDe\lambda_{De} and velocities 1 to 3 times the background electron thermal speed. Nonlinear wave packets of similar velocities and scales are also observed, indicating that the two descend from the same mode which is consistent with the electrostatic whistler mode and result from an instability likely to be driven by field-aligned currents.Comment: 5 pages, 4 figures http://link.aps.org/doi/10.1103/PhysRevLett.105.11500

    Sox5 and Sox6 are needed to develop and maintain source, columnar, and hypertrophic chondrocytes in the cartilage growth plate

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    Sox5 and Sox6 encode Sry-related transcription factors that redundantly promote early chondroblast differentiation. Using mouse embryos with three or four null alleles of Sox5 and Sox6, we show that they are also essential and redundant in major steps of growth plate chondrocyte differentiation. Sox5 and Sox6 promote the development of a highly proliferating pool of chondroblasts between the epiphyses and metaphyses of future long bones. This pool is the likely cellular source of growth plates. Sox5 and Sox6 permit formation of growth plate columnar zones by keeping chondroblasts proliferating and by delaying chondrocyte prehypertrophy. They allow induction of chondrocyte hypertrophy and permit formation of prehypertrophic and hypertrophic zones by delaying chondrocyte terminal differentiation induced by ossification fronts. They act, at least in part, by down-regulating Ihh signaling, Fgfr3, and Runx2 and by up-regulating Bmp6. In conclusion, Sox5 and Sox6 are needed for the establishment of multilayered growth plates, and thereby for proper and timely development of endochondral bones

    One single static measurement predicts wave localization in complex structures

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    A recent theoretical breakthrough has brought a new tool, called \emph{localization landscape}, to predict the localization regions of vibration modes in complex or disordered systems. Here, we report on the first experiment which measures the localization landscape and demonstrates its predictive power. Holographic measurement of the static deformation under uniform load of a thin plate with complex geometry provides direct access to the landscape function. When put in vibration, this system shows modes precisely confined within the sub-regions delineated by the landscape function. Also the maxima of this function match the measured eigenfrequencies, while the minima of the valley network gives the frequencies at which modes become extended. This approach fully characterizes the low frequency spectrum of a complex structure from a single static measurement. It paves the way to the control and engineering of eigenmodes in any vibratory system, especially where a structural or microscopic description is not accessible.Comment: 5 pages, 4 figure

    Projected seniority-two orbital optimization of the Antisymmetric Product of one-reference orbital Geminal

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    We present a new, non-variational orbital-optimization scheme for the Antisymmetric Product of one-reference orbital Geminal wave function. Our approach is motivated by the observation that an orbital-optimized seniority-zero configuration interaction (CI) expansion yields similar results to an orbital-optimized seniority-zero-plus-two CI expansion [J. Chem. Phys., 135, 044119 (2011)]. A numerical analysis is performed for the C2_2, LiF and CH2_2 molecules as well as for the symmetric stretching of hypothetical (linear) hydrogen chains. For these test cases, the proposed orbital-optimization protocol yields similar results to its variational orbital optimization counterpart, but prevents symmetry-breaking of molecular orbitals in most cases.Comment: 7 pages, 2 figure

    Recent exposure to ultrafine particles in school children alters miR-222 expression in the extracellular fraction of saliva

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    Background: Ultrafine particles (< 100 nm) are ubiquitous present in the air and may contribute to adverse cardiovascular effects. Exposure to air pollutants can alter miRNA expression, which can affect downstream signaling pathways. miRNAs are present both in the intracellular and extracellular environment. In adults, miR-222 and miR-146a were identified as associated with particulate matter exposure. However, there is little evidence of molecular effects of ambient air pollution in children. This study examined whether exposure to fine and ultrafine particulate matter (PM) is associated with changes in the extracellular content of miR-222 and miR-146a of children. Methods: Saliva was collected from 80 children at two different time points, circa 11 weeks apart and stabilized for RNA preservation. The extracellular fraction of saliva was obtained by means of differential centrifugation and ultracentrifugation. Expression levels of miR-222 and miR-146a were profiled by qPCR. We regressed the extracellular miRNA expression against recent exposure to ultrafine and fine particles measured at the school site using mixed models, while accounting for sex, age, BMI, passive smoking, maternal education, hours of television use, time of the day and day of the week. Results: Exposure to ultrafine particles (UFP) at the school site was positively associated with miR-222 expression in the extracellular fraction in saliva. For each IQR increase in particles in the class room (+8504 particles/cm(3)) or playground (+ 28776 particles/cm(3)), miR-222 was, respectively 23.5 % (95 % CI: 3.5 %-41.1 %; p = 0.021) or 29.9 % (95 % CI: 10.6 %-49.1 %; p = 0.0027) higher. No associations were found between miR-146a and recent exposure to fine and ultrafine particles. Conclusions: Our results suggest a possible epigenetic mechanism via which cells respond rapidly to small particles, as exemplified by miR-222 changes in the extracellular fraction of saliva

    Impact of atypical long-acting injectable versus oral antipsychotics on rehospitalization rates and emergency room visits among relapsed schizophrenia patients: a retrospective database analysis

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    BACKGROUND: Among schizophrenia patients relapsed on an oral antipsychotic (AP), this study compared the impact of switching to atypical AP long-acting injectable therapy (LAT) versus continuing oral APs on hospitalization and emergency room (ER) visit recurrence. METHODS: Electronic records from the Premier Hospital Database (2006-2010) were analyzed. Adult patients receiving oral APs during a schizophrenia-related hospitalization were identified and, upon relapse (i.e., rehospitalization for schizophrenia), were stratified into (a) patients switching to atypical LAT and (b) patients continuing with oral APs. Atypical LAT relapse patients were matched 1:3 with oral AP relapse patients, using a propensity score model. Andersen-Gill Cox proportional hazards models assessed the impact of atypical LAT versus oral AP on time to multiple recurrences of all-cause hospitalizations and ER visits. No adjustment was made for multiplicity. RESULTS: Atypical LAT (N = 1032) and oral AP (N = 2796) patients were matched and well-balanced with respect to demographic (mean age: 42.1 vs 42.4 years, p = .5622; gender: 43.6% vs 44.6% female, p = .5345), clinical, and hospital characteristics. Over a mean 30-month follow-up period, atypical LATs were associated with significantly lower mean number of rehospitalizations (1.25 vs 1.61, p < .0001) and ER visits (2.33 vs 2.67, p = .0158) compared with oral APs, as well as fewer days in hospital (mean days: 13.46 vs. 15.69, p = .0081). Rehospitalization (HR 0.81, 95% CI 0.76–0.87, p < .0001) and ER visit (HR 0.88, 95% CI 0.87–0.93, p < .0001) rates were significantly lower for patients receiving atypical LAT versus oral APs. CONCLUSIONS: This hospital database analysis found that in relapsed schizophrenia patients, atypical LATs were associated with lower rehospitalization and ER visit rates than oral APs
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