4,557 research outputs found

    Hermitian Dirac Hamiltonian in time dependent gravitational field

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    It is shown by a straightforward argument that the Hamiltonian generating the time evolution of the Dirac wave function in relativistic quantum mechanics is not hermitian with respect to the covariantly defined inner product whenever the background metric is time dependent. An alternative, hermitian, Hamiltonian is found and is shown to be directly related to the canonical field Hamiltonian used in quantum field theory.Comment: 9 pages, final version, to appear in Class. Quant. Gra

    Real-time RT-PCR analysis of mRNA decay: half-life of Beta-actin mRNA in human leukemia CCRF-CEM and Nalm-6 cell lines

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    BACKGROUND: We describe an alternative method to determine mRNA half-life (t(1/2)) based on the Real-Time RT-PCR procedure. This approach was evaluated by using the β-actin gene as a reference molecule for measuring of mRNA stability. RESULTS: Human leukemia Nalm-6 and CCRF-CEM cells were treated with various concentrations of Actinomycin D to block transcription and aliquots were removed periodically. Total RNA was isolated and quantified using the RiboGreen(®) fluorescent dye with the VersaFluor Fluorometer System. One μg of total RNA was reverse transcribed and used as template for the amplification of a region of the β-actin gene (231 bp). To generate the standard curve, serial ten-fold dilutions of the pBactin-231 vector containing the cDNA amplified fragment were employed, β-actin mRNAs were quantified by Real-Time RT-PCR using the SYBR(®) Green I fluorogenic dye and data analyzed using the iCycle iQ system software. Using this method, the β-actin mRNA exhibited a half-life of 6.6 h and 13.5 h in Nalm-6 and CCRF-CEM cells, respectively. The t(1/2) value obtained for Nalm-6 is comparable to those estimated from Northern blot studies, using normal human leukocytes (5.5 h). CONCLUSIONS: We have developed a rapid, sensitive, and reliable method based on Real-Time RT-PCR for measuring mRNA half-life. Our results confirm that β-actin mRNA half-life can be affected by the cellular growth rate

    On dual canonical bases

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    The dual basis of the canonical basis of the modified quantized enveloping algebra is studied, in particular for type AA. The construction of a basis for the coordinate algebra of the n×nn\times n quantum matrices is appropriate for the study the multiplicative property. It is shown that this basis is invariant under multiplication by certain quantum minors including the quantum determinant. Then a basis of quantum SL(n) is obtained by setting the quantum determinant to one. This basis turns out to be equivalent to the dual canonical basis

    Situational Precipitators and Interactive Forces in Sexual Crime Events Involving Adult Offenders

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    We investigated the role of situational precipitators in sexual offenses in relation to the use of physical force by offenders, penetration of the victim, and physical injuries to the victim. We used self-report data obtained from a Canadian sample of 553 incarcerated adult male sexual offenders. All data used in this study were gathered through a semi-structured interview conducted with each participant. First, we found that 75.8% of sexual crime events were somehow precipitated, or characterized, by the presence of precipitators before crime. Second, the relationship between each precipitator and the type of offense was statistically significant except for one precipitator. Third, although a number of precipitators were associated with the dependent variables, we also found two interaction effects that illuminated the complexity of the role of precipitators in sexual offenses. Interaction analysis can increase our understanding of sexual crime events and better inform prevention practices, such as relapse prevention

    Feasibility and Accessibility of a Tailored Intervention for Informal Caregivers of People with Severe Psychiatric Disorders: a Pilot Study

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    Objectives: This study aimed to assess the acceptability and feasibility of a new tailored intervention for informal caregivers: the Ensemble (Together) program. Methods: An open pre–post within-subject comparison pilot study was conducted. Twenty-one informal caregivers completed the five-session Ensemble program. Two measurement tools were used: The Brief Symptom Inventory (BSI) and the Life Orientation Scale (LOT-R). Results: The results showed that informal caregivers were in need of individual support and were ready to participate in the Ensemble program independent of the patient’s diagnosis or stage of illness. The participants were very satisfied, and 95.4% completed the program. The preliminary results also showed that in five sessions, informal caregivers’ Global Severity Index measured by the BSI and their optimism about their future (measured by the LOT-R) were significantly improved. Conclusion: This pilot study provided preliminary results concerning the feasibility and acceptability of the tailored Ensemble program and indicates the need for a randomized trial. The Ensemble program is appropriate for both the acute and chronic phases of disease. Individualized brief and useful interventions for informal caregivers may provide more positive outcomes in care

    Manual do Sistema Balanço Hídrico e Calendário Agrícola.

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    Manual do Sistema Balanço Hídrico; Explicação e observações sobre os termos empregados nas tabelas do Balanço Hídrico; Modelo Entidade Relacionamento (MER); Objetivo operacional do sistema; Diferenciamento das duas maneiras de processamento do sistema; Funcionamento; Módulo arquivos; Módulo Balanço Hídrico; Módulo Utilitário; Módulo Sobre.bitstream/item/116808/1/834.pd

    Projection-based measurement and identification

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    A recently developed Projection-based Digital Image Correlation (P-DVC) method is here extended to 4D (space and time) displacement field measurement and mechanical identification based on a single radiograph per loading step instead of volumes as in standard DVC methods. Two levels of data reductions are exploited, namely, reduction of the data acquisition (and time) by a factor of 1000 and reduction of the solution space by exploiting model reduction techniques. The analysis of a complete tensile elastoplastic test composed of 127 loading steps performed in 6 minutes is presented. The 4D displacement field as well as the elastoplastic constitutive law are identified. Keywords: Image-based identification, Model reduction, Fast 4D identification, In-situ tomography measurements. INTRODUCTION Identification and validation of increasingly complex mechanical models is a major concern in experimental solid mechanics. The recent developments of computed tomography coupled with in-situ tests provide extremely rich and non-destructive analyses [1]. In the latter cases, the sample was imaged inside a tomograph, either with interrupted mechanical load or with a continuously evolving loading and on-the-fly acquisitions (as ultra-fast X-ray synchrotron tomography, namely, 20 Hz full scan acquisition for the study of crack propagation [2]). Visualization of fast transformations, crack openings, or unsteady behavior become accessible. Combined with full-field measurements, in-situ tests offer a quantitative basis for identifying a broad range of mechanical behavior.Comment: SEM 2019, Jun 2019, Reno, United State
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