229 research outputs found

    Study Methodology

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    Data for this investigation come from 36 qualitative in-depth interviews completed between February and April 2010. The aim of the research was to conduct a process evaluation of Gateway Foundation programming for state probation and parole clients in St. Louis and jointly produce a final report for the organization. The specific research questions focused on (1) the challenges men face as they attempt to overcome substance abuse; (2) how those challenges are related to past experiences with crime, including offending and victimization; and (3) the effectiveness of Gateway programming, from the points of view of program participants, including whether there are any perceived differences between men who participate in the program post-incarceration versus in lieu of incarceration

    Asymptotics of Expansion of the Evolution Operator Kernel in Powers of Time Interval Δt\Delta t

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    The upper bound for asymptotic behavior of the coefficients of expansion of the evolution operator kernel in powers of the time interval \Dt was obtained. It is found that for the nonpolynomial potentials the coefficients may increase as n!n!. But increasing may be more slow if the contributions with opposite signs cancel each other. Particularly, it is not excluded that for number of the potentials the expansion is convergent. For the polynomial potentials \Dt-expansion is certainly asymptotic one. The coefficients increase in this case as Γ(nL2L+2)\Gamma(n \frac{L-2}{L+2}), where LL is the order of the polynom. It means that the point \Dt=0 is singular point of the kernel.Comment: 12 pp., LaTe

    New Approach for Measuring Vub|V_{ub}| at Future BB-Factories

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    It is suggested that the measurements of hadronic invariant mass (mXm_X) distributons in the inclusive BXc(u)lνB \rightarrow X_{c(u)} l \nu decays can be useful in extracting the CKM matrix element Vub|V_{ub}|. We investigated hadronic invariant mass distributions within the various theoretical models of HQET, FAC and chiral lagrangian as well as ACCMM model. It is also emphasized that the mXm_X distribution even at the region mX>mDm_{X} > m_{D} in the inclusive bub\rightarrow u are effetive in selecting the events, experimentally viable at the future asymmetric BB factories, with better theoretical understandings.Comment: 11 pages not including 1 figur

    Decay Constants and Semileptonic Decays of Heavy Mesons in Relativistic Quark Model

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    We investigate the BB and DD mesons in the relativistic quark model by applying the variational method with the Gaussian wave function. We calculate the Fermi momentum parameter pFp_{_F}, and obtain pF=0.500.54p_{_F} = 0.50 \sim 0.54 GeV, which is almost independent of the input parameters, αs\alpha_s, mbm_b, mcm_c and mspm_{sp}. We then calculate the ratio fBf_B/fDf_D, and obtain the result which is larger, by the factor of about 1.3, than MD/MB\sqrt{M_D / M_B} given by the naive nonrelativistic analogy. This result is in a good agreement with the recent Lattice calculations. We also calculate the ratio (MBMB)(M_{B^*}-M_{B})/(MDMD)(M_{D^*}-M_{D}). In these calculations the wave function at origin ψ(0)\psi (0) is essential. We also determine pFp_{_F} by comparing the theoretical prediction of the ACCMM model with the lepton energy spectrum of BeνXB \rightarrow e \nu X from the recent ARGUS analysis, and find that pF=0.27 ± 0.270.22p_{_F}=0.27~\pm~^{0.22}_{0.27} GeV, when we use mc=1.5m_c=1.5 GeV. However, this experimentally determined value of pFp_{_F} is strongly dependent on the value of input parameter mcm_c.Comment: 15 pages (Latex) (uses epsfig.sty, 1 figure appended as a uuencoded compressed ps-file

    Dependence of Variational Perturbation Expansions on Strong-Coupling Behavior. Inapplicability of delta-Expansion to Field Theory

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    We show that in applications of variational theory to quantum field theory it is essential to account for the correct Wegner exponent omega governing the approach to the strong-coupling, or scaling limit. Otherwise the procedure either does not converge at all or to the wrong limit. This invalidates all papers applying the so-called delta-expansion to quantum field theory.Comment: Author Information under http://www.physik.fu-berlin.de/~kleinert/institution.html . Latest update of paper (including all PS fonts) at http://www.physik.fu-berlin.de/~kleinert/34

    Test of Factorization Hypothesis from Exclusive Non-leptonic B decays

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    We investigate the possibility of testing factorization hypothesis in non-leptonic exclusive decays of B-meson. In particular, we considered the non factorizable \bar{B^0} -> D^{(*)+} D_s^{(*)-} modes and \bar{B^0} -> D^{(*)+} (\pi^-, \rho^-) known as well-factorizable modes. By taking the ratios BR(\bar{B^0}-> D^{(*)+}D_s^{(*)-})/BR(\bar{B^0}-> D^{(*)+}(\pi^-,\rho^-)), we found that under the present theoretical and experimental uncertainties there's no evidence for the breakdown of factorization description to heavy-heavy decays of the B meson.Comment: 11 pages; submitted to PR

    Dependence of Vub/Vcb|V_{ub}/V_{cb}| on Fermi momentum pFp_{_F} in ACCMM model

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    The Gaussian width of Fermi momentum, pFp_{_F}, is the most important parameter of the ACCMM model, and its value is essential in the determination of Vub/Vcb|V_{ub}/V_{cb}| because the experimental analysis is allowed only at the end-point region of inclusive semileptonic BB-decay spectrum. We extract the value of Vub/Vcb|V_{ub}/V_{cb}| as a function of pFp_{_F}. We also calculate the parameter pFp_{_F} in the relativistic quark model using the variational method, and obtain pF=0.54p_{_F} = 0.54 GeV which is much larger than the commonly used value, 0.3\sim 0.3 GeV, in experimental analyses. When we use pF=0.5p_{_F} = 0.5 GeV instead of 0.3 GeV, the value of Vub/Vcb|V_{ub}/V_{cb}| from ACCMM model is increased by a factor 1.81, and can give a good agreement with Isgur {\it et al.} model.Comment: 1. Section 2 has been revised by considering the fact that in the real experimental situation the only measured quantity is the number of events in the high ElE_l region compared to the total semi- leptonic event number. 2. The article by C. Greub and D. Wyler (Phys. Lett. B295 (1992) 293) has been included in references, which reports a similar conclusion for the value of pFp_{_F} (pFp_{_F}=566 MeV), even though they used the different approach. 3. This article will be published in Z. Phys. C (1995

    Arsenic Trioxide Modulates DNA Synthesis and Apoptosis in Lung Carcinoma Cells

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    Arsenic trioxide, the trade name Trisenox, is a drug used to treat acute promyleocytic leukemia (APL). Studies have demonstrated that arsenic trioxide slows cancer cells growth. Although arsenic influences numerous signal-transduction pathways, cell-cycle progression, and/or apoptosis, its apoptotic mechanisms are complex and not entirely delineated. The primary objective of this research was to evaluate the effects of arsenic trioxide on DNA synthesis and to determine whether arsenic-induced apoptosis is mediated via caspase activation, p38 mitogen–activated protein kinase (MAPK), and cell cycle arrest. To achieve this goal, lung cancer cells (A549) were exposed to various concentrations (0, 2, 4, 6, 8, and 10 μg/mL) of arsenic trioxide for 48 h. The effect of arsenic trioxide on DNA synthesis was determined by the [3H]thymidine incorporation assay. Apoptosis was determined by the caspase-3 fluorescein isothiocyanate (FITC) assay, p38 MAP kinase activity was determined by an immunoblot assay, and cell-cycle analysis was evaluated by the propidium iodide assay. The [3H]thymidine-incorporation assay revealed a dose-related cytotoxic response at high levels of exposure. Furthermore, arsenic trioxide modulated caspase 3 activity and induced p38 MAP kinase activation in A549 cells. However, cell-cycle studies showed no statistically significant differences in DNA content at subG1 check point between control and arsenic trioxide treated cells

    Wide Contact Structures for Low-Noise Nanochannel Devices Based on a Carbon Nanotube Network

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    We have developed a wide contact structure for low-noise nanochannel devices based on a carbon nanotube (CNT) network. This low-noise CNT network-based device has a dumbbell-shaped channel, which has wide CNT/electrode contact regions and, in effect, reduces the contact noise. We also performed a systematic analysis of structured CNT networks and established an empirical formula that can explain the noise behavior of arbitrary-shaped CNT network-based devices including the effect of contact regions and CNT alignment. Interestingly, our analysis revealed that the noise amplitude of aligned CNT networks behaves quite differently compared with that of randomly oriented CNT networks. Our results should be an important guideline in designing low-noise nanoscale devices based on a CNT network for various applications such as a highly sensitive low-noise sensor

    Research productivity and academics’ conceptions of research

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    This paper asks the question: do people with different levels of research productivity and identification as a researcher think of research differently? It discusses a study that differentiated levels of research productivity among English and Australian academics working in research-intensive environments in three broad discipline areas: science, engineering and technology; social science and humanities; and medicine and health sciences. The paper explores the different conceptions of research held by these academics in terms of their levels of research productivity, their levels of research training, whether they considered themselves an active researcher and a member of a research team, and their disciplinary differences
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