690 research outputs found

    Gauge field theories with covariant star-product

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    A noncommutative gauge theory is developed using a covariant star-product between differential forms defined on a symplectic manifold, considered as the space-time. It is proven that the field strength two-form is gauge covariant and satisfies a deformed Bianchi identity. The noncommutative Yang-Mills action is defined using a gauge covariant metric on the space-time and its gauge invariance is proven up to the second order in the noncommutativity parameter.Comment: Dedicated to Ioan Gottlieb on the occasion of his 80th birthday anniversary. 12 page

    Dissociative electron attachment to the H2O molecule. II. Nuclear dynamics on coupled electronic surfaces within the local complex potential model

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    We report the results of a first-principles study of dissociative electron attachment to H2O. The cross sections are obtained from nuclear dynamics calculations carried out in full dimensionality within the local complex potential model by using the multi-configuration time-dependent Hartree method. The calculations employ our previously obtained global, complex-valued, potential-energy surfaces for the three (doublet B1, doublet A1, and doublet B2) electronic Feshbach resonances involved in this process. These three metastable states of H2O- undergo several degeneracies, and we incorporate both the Renner-Teller coupling between the B1 and A1 states as well as the conical intersection between the A1 and B2 states into our treatment. The nuclear dynamics are inherently multidimensional and involve branching between different final product arrangements as well as extensive excitation of the diatomic fragment. Our results successfully mirror the qualitative features of the major fragment channels observed, but are less successful in reproducing the available results for some of the minor channels. We comment on the applicability of the local complex potential model to such a complicated resonant system.Comment: Corrected version of Phys Rev A 75, 012711 (2007

    Multi-cell soft errors at the 16-nm FinFET technology node

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    Dissociative electron attachment to the H2O molecule. I. Complex-valued potential-energy surfaces for the 2B1, 2A1, and 2B2 metastable states of the water anion

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    We present the results of calculations defining global, three-dimensional representations of the complex-valued potential-energy surfaces of the doublet B1, doublet A1, and doublet B2 metastable states of the water anion that underlie the physical process of dissociative electron attachment to water. The real part of the resonance energies is obtained from configuration-interaction calculations performed in a restricted Hilbert space, while the imaginary part of the energies (the widths) is derived from complex Kohn scattering calculations. A diabatization is performed on the 2A1 and 2B2 surfaces, due to the presence of a conical intersection between them. We discuss the implications that the shapes of the constructed potential-energy surfaces will have upon the nuclear dynamics of dissociative electron attachment to H2O. This work originally appeared as Phys Rev A 75, 012710 (2007). Typesetting errors in the published version have been corrected here.Comment: Corrected version of PRA 75, 012710 (2007

    Predicting participation in group parenting education in an Australian sample: The role of attitudes, norms, and control factors

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    We examined the theory of planned behavior (TPB) in predicting intentions to participate in group parenting education. One hundred and seventy-six parents (138 mothers and 38 fathers) with a child under 12 years completed TPB items assessing attitude, subjective norms, perceived behavioral control (PBC), and two additional social influence variables (self-identity and group norm). Regression analyses supported the TPB predictors of participation intentions with self-identity and group norm also significantly predicting intentions. These findings offer preliminary support for the TPB, along with additional sources of social influence, as a useful predictive model of participation in parenting education

    Norm estimates of complex symmetric operators applied to quantum systems

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    This paper communicates recent results in theory of complex symmetric operators and shows, through two non-trivial examples, their potential usefulness in the study of Schr\"odinger operators. In particular, we propose a formula for computing the norm of a compact complex symmetric operator. This observation is applied to two concrete problems related to quantum mechanical systems. First, we give sharp estimates on the exponential decay of the resolvent and the single-particle density matrix for Schr\"odinger operators with spectral gaps. Second, we provide new ways of evaluating the resolvent norm for Schr\"odinger operators appearing in the complex scaling theory of resonances

    Wave packet evolution approach to ionization of hydrogen molecular ion by fast electrons

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    The multiply differential cross section of the ionization of hydrogen molecular ion by fast electron impact is calculated by a direct approach, which involves the reduction of the initial 6D Schr\"{o}dinger equation to a 3D evolution problem followed by the modeling of the wave packet dynamics. This approach avoids the use of stationary Coulomb two-centre functions of the continuous spectrum of the ejected electron which demands cumbersome calculations. The results obtained, after verification of the procedure in the case atomic hydrogen, reveal interesting mechanisms in the case of small scattering angles.Comment: 7 pages, 8 Postscript figure

    Global State Measures of the Dentate Gyrus Gene Expression System Predict Antidepressant-Sensitive Behaviors

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    Background Selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine are the most common form of medication treatment for major depression. However, approximately 50% of depressed patients fail to achieve an effective treatment response. Understanding how gene expression systems respond to treatments may be critical for understanding antidepressant resistance. Methods We take a novel approach to this problem by demonstrating that the gene expression system of the dentate gyrus responds to fluoxetine (FLX), a commonly used antidepressant medication, in a stereotyped-manner involving changes in the expression levels of thousands of genes. The aggregate behavior of this large-scale systemic response was quantified with principal components analysis (PCA) yielding a single quantitative measure of the global gene expression system state. Results Quantitative measures of system state were highly correlated with variability in levels of antidepressant-sensitive behaviors in a mouse model of depression treated with fluoxetine. Analysis of dorsal and ventral dentate samples in the same mice indicated that system state co-varied across these regions despite their reported functional differences. Aggregate measures of gene expression system state were very robust and remained unchanged when different microarray data processing algorithms were used and even when completely different sets of gene expression levels were used for their calculation. Conclusions System state measures provide a robust method to quantify and relate global gene expression system state variability to behavior and treatment. State variability also suggests that the diversity of reported changes in gene expression levels in response to treatments such as fluoxetine may represent different perspectives on unified but noisy global gene expression system state level responses. Studying regulation of gene expression systems at the state level may be useful in guiding new approaches to augmentation of traditional antidepressant treatments

    Assessing the Cultural Appropriateness of UPLIFT for African Americans With Epilepsy: A Community Engaged Approach

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    Background: In trials of Project UPLIFT, a distance-delivered, mindfulness-based cognitive therapy intervention, there was improvement in the mental health of people with epilepsy/seizure disorder. In these trials, however, African Americans have been few. Thus, as this program is disseminated, it is desirable to ensure that it is culturally appropriate for minority populations. Methods: To determine the appropriateness of Project UPLIFT for African Americans, we engaged in three main research activities: 1) the formation and involvement of an epilepsy community advisory board; 2) qualitative interviews with healthcare providers who serve this community; and 3) focus groups with African American adults living with epilepsy or seizure disorder and main support persons of African American adults living with epilepsy or seizure disorder. Results: The epilepsy community advisory board provided recommendations for the most appropriate language to use when engaging and recruiting the target population. Healthcare providers indicated that psychosocial concerns of African American persons living with epilepsy seemed to be different from those among patients of other racial groups. They indicated that Project UPLIFT might be useful for this group. Focus groups revealed experiences of living with and supporting someone with epilepsy and provided favorable feedback on the UPLIFT intervention. Conclusions: Formative feedback indicates that Project UPLIFT may be useful for African Americans with epilepsy. These data will be used to guide a forthcoming randomized, controlled trial to assess the acceptability and feasibility of the intervention with this group
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