145 research outputs found

    Is it possible to construct excited-state energy functionals by splitting k-space?

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    We show that our procedure of constructing excited-state energy functionals by splitting k-space, employed so far to obtain exchange energies of excited-states, is quite general. We do so by applying the same method to construct modified Thomas-Fermi kinetic energy functional and its gradient expansion up to the second order for the excited-states. We show that the resulting kinetic energy functional has the same accuracy for the excited-states as the ground-state functionals do for the ground-states.Comment: 20 pages, 1 figur

    Tax Policy, Investments in Human and Physical Capital, and Productivity

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    This paper analyzes the implications of tax policy for the accumulation of human and physical capital and for the overall productivity level of the economy. A comprehensive income tax, applying to both labour income and capital income. discriminates against investments in human capital relative to investments in physical capital. Hence. it has an adverse impact on human capital accumulation. Taking into account a positive external effect of investments in human capital on overall productivity, the adverse effect of income taxation on human capital investments is significantly magnified.

    Resonance Lifetimes from Complex Densities

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    The ab-initio calculation of resonance lifetimes of metastable anions challenges modern quantum-chemical methods. The exact lifetime of the lowest-energy resonance is encoded into a complex "density" that can be obtained via complex-coordinate scaling. We illustrate this with one-electron examples and show how the lifetime can be extracted from the complex density in much the same way as the ground-state energy of bound systems is extracted from its ground-state density

    Mass Parameterizations and Predictions of Isotopic Observables

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    We discuss the accuracy of mass models for extrapolating to very asymmetric nuclei and the impact of such extrapolations on the predictions of isotopic observables in multifragmentation. We obtain improved mass predictions by incorporating measured masses and extrapolating to unmeasured masses with a mass formula that includes surface symmetry and Coulomb terms. We find that using accurate masses has a significant impact on the predicted isotopic observables.Comment: 12 pages, 4 figure

    Onset of Perturbative Color Opacity at Small x and Upsilon Coherent Photoproduction off heavy nuclei at LHC

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    We study photon-induced coherent production of Upsilon in ultraperipheral heavy ion collisions at LHC and demonstrate that the counting rates will be sufficient to measure nuclear shadowing of generalized gluon distributions. This will establish the transition from the regime of color transparency to the regime of perturbative color opacity in an unambiguous way. We argue that such measurements will provide the possibility to investigate the interaction of ultra-small color dipoles with nuclei in QCD at large energies, which are beyond the reach of the electron-nucleon (nucleus) colliders, and will unambiguously discriminate between the leading twist and higher twist scenarios of gluon nuclear shadowing.Comment: 14 pages, 4 figure

    Effective suppression of Dengue fever virus in mosquito cell cultures using retroviral transduction of hammerhead ribozymes targeting the viral genome

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    Outbreaks of Dengue impose a heavy economic burden on developing countries in terms of vector control and human morbidity. Effective vaccines against all four serotypes of Dengue are in development, but population replacement with transgenic vectors unable to transmit the virus might ultimately prove to be an effective approach to disease suppression, or even eradication. A key element of the refractory transgenic vector approach is the development of transgenes that effectively prohibit viral transmission. In this report we test the effectiveness of several hammerhead ribozymes for suppressing DENV in lentivirus-transduced mosquito cells in an attempt to mimic the transgenic use of these effector molecules in mosquitoes. A lentivirus vector that expresses these ribozymes as a fusion RNA molecule using an Ae. aegypti tRNAval promoter and terminating with a 60A tail insures optimal expression, localization, and activity of the hammerhead ribozyme against the DENV genome. Among the 14 hammerhead ribozymes we designed to attack the DENV-2 NGC genome, several appear to be relatively effective in reducing virus production from transduced cells by as much as 2 logs. Among the sequences targeted are 10 that are conserved among all DENV serotype 2 strains. Our results confirm that hammerhead ribozymes can be effective in suppressing DENV in a transgenic approach, and provide an alternative or supplementary approach to proposed siRNA strategies for DENV suppression in transgenic mosquitoes

    RNAi for Treating Hepatitis B Viral Infection

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    Chronic hepatitis B virus (HBV) infection is one of the leading causes of liver cirrhosis and hepatocellular carcinoma (HCC). Current treatment strategies of HBV infection including the use of interferon (IFN)-α and nucleotide analogues such as lamivudine and adefovir have met with only partial success. Therefore, it is necessary to develop more effective antiviral therapies that can clear HBV infection with fewer side effects. RNA interference (RNAi), by which a small interfering RNA (siRNA) induces the gene silence at a post-transcriptional level, has the potential of treating HBV infection. The successful use of chemically synthesized siRNA, endogenous expression of small hairpin RNA (shRNA) or microRNA (miRNA) to silence the target gene make this technology towards a potentially rational therapeutics for HBV infection. However, several challenges including poor siRNA stability, inefficient cellular uptake, widespread biodistribution and non-specific effects need to be overcome. In this review, we discuss several strategies for improving the anti-HBV therapeutic efficacy of siRNAs, while avoiding their off-target effects and immunostimulation. There is an in-depth discussion on the (1) mechanisms of RNAi, (2) methods for siRNA/shRNA production, (3) barriers to RNAi-based therapies, and (4) delivery strategies of siRNA for treating HBV infection

    Photoproduction of J/psi and of high mass e+e- in ultra-peripheral Au+Au collisions at sqrt(s_NN) = 200 GeV

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    We present the first measurement of photoproduction of J/psi and of two-photon production of high-mass e+e- pairs in electromagnetic (or ultra-peripheral) nucleus-nucleus interactions, using Au+Au data at sqrt(s_NN) = 200 GeV. The events are tagged with forward neutrons emitted following Coulomb excitation of one or both Au^{star} nuclei. The event sample consists of 28 events with m_{e+e-} > 2 GeV/c^2 with zero like-sign background. The measured cross sections at midrapidity of d\sigma / dy (J/psi + Xn, y=0) = 76 +/- 33 (stat) +/- 11 (syst) micro b and d^2\sigma/dm dy (e^+e^- + Xn, y=0) = 86 +/- 23 (stat) +/- 16 (syst) micro b/(GeV/c^2) for m_{e+e-} \in [2.0,2.8] GeV/c^2 are consistent with various theoretical predictions.Comment: 345 authors from 52 institutions, 20 pages, 4 figures, 3 tables. Submitted to Physics Letters B. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm
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