295 research outputs found

    Nuclear Polarizabilities and Logarithmic Sum Rules

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    The electric polarizability and logarithmic mean-excitation energy are calculated for the deuteron using techniques introduced in atomic physics. These results are then used to improve limits on the atomic-deuterium frequency shift due to nuclear polarization in the unretarded dipole limit, as well as confirming previous results.Comment: 7 pages, latex -- To appear in Phys. Rev. C -

    Managed trade: The US–Mexico sugar suspension agreements

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    Under the 1994 North American Free Trade Agreement, Mexican sugar producers were ultimately granted free access to the US sugar market, while all other suppliers, including US refiners, were subject to supply quotas. Following a surge in imports of Mexican sugar, the American Sugar Coalition initiated anti‐dumping and countervailing duty (ADCVD) proceedings against Mexico in early 2014. In December 2014, the ADCVD cases were halted as a result of two suspension agreements negotiated between the US and Mexico. This paper contributes to a small number of empirical studies that have estimated the impact of suspension agreements. We measure the impacts of the ADCVD filings and the suspension agreements on US domestic raw and refined prices, the raw‐to‐refined margin and the quantity and composition of sugar imports from Mexico. Results suggest US raw sugar prices increased by 3¢ per lb. (14%) under ADCVD proceedings, equivalent to an ad valorem tariff between 40% and 50%, while the suspension agreements increased US raw sugar prices by 5¢ (70% tariff equivalent). US refined sugar prices increased by similar amounts under the ADCVD proceedings and the suspension agreements (4.5¢ per lb.). Ultimately, both the ADCVD proceedings and the suspension agreements significantly reduced sugar imports from Mexico. US sugar refiner economic welfare hinges critically on the quantity and composition of raw sugar imports. As such, refiner revenue, following the ADCVD filings and suspension agreements, is estimated to have declined by 16%, relative to a free trade environment

    Higher-Order Nuclear-Polarizability Corrections in Atomic Hydrogen

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    Nuclear-polarizability corrections that go beyond unretarded-dipole approximation are calculated analytically for hydrogenic (atomic) S-states. These retardation corrections are evaluated numerically for deuterium and contribute -0.68 kHz, for a total polarization correction of 18.58(7) kHz. Our results are in agreement with one previous numerical calculation, and the retardation corrections completely account for the difference between two previous calculations. The uncertainty in the deuterium polarizability correction is substantially reduced. At the level of 0.01 kHz for deuterium, only three primary nuclear observables contribute: the electric polarizability, αE\alpha_E, the paramagnetic susceptibility, βM\beta_M, and the third Zemach moment, (2)_{(2)}. Cartesian multipole decomposition of the virtual Compton amplitude and its concomitant gauge sum rules are used in the analysis.Comment: 26 pages, latex, 1 figure -- Submitted to Phys. Rev. C -- epsfig.sty require

    The Optimal Design of Trade Policy Flexibility in the WTO

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    This paper is a contribution to the literature on rational design of trade agreements. The World Trade Organization (WTO) is an incomplete contract among sovereign states. Incomplete contracts contain gaps. Ex post, contractual gaps may leave gains from trade unrealized; they may create 'regret' in signatories once unanticipated contingencies or sudden protectionist backlashes have occurred. Trade policy flexibility mechanisms, such as the 'safeguards clause' under Art. XIX GATT, are geared towards seizing ex post regret by allowing parties affected by a protectionist shock to partially and temporarily withdraw from previously made trade liberalization concessions - given that they compensate the victim(s) of such backtracking behavior. This paper examines the somewhat understudied issue of optimal trade policy flexibility design in the WTO: In particular, we analyze whether ex post escape should be organized by means of a unilateral opt-out clause (a 'liability rule' of escape), or a bilateral renegotiation provision (a 'property rule' of escape). Modeling the WTO as a fully non-contingent tariff liberalization contract with contingencies (or 'states of nature') asymmetrically revealed, we find that a liability rule backed by expectation remedies payable to the affected victim Pareto-dominates both a renegotiation clause, as well as any other remedy arrangement connected to a liability rule. Only the remedial design of liability-cum-expectation damages yields the desirable incentives to liberalize ex ante, and to default ex post and therewith is able to replicate the outcomes of the hypothetical contracting ideal of the complete contingent contract

    Lancet commission on hypertension group position statement on the global improvement of accuracy standards for devices that measure blood pressure

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    The Lancet Commission on Hypertension identified that a key action to address the worldwide burden of high blood pressure (BP) was to improve the quality of BP measurements by using BP devices that have been validated for accuracy. Currently, there are over 3000 commercially available BP devices, but many do not have published data on accuracy testing according to established scientific standards. This problem is enabled through weak or absent regulations that allow clearance of devices for commercial use without formal validation. In addition, new BP technologies have emerged (e.g. cuffless sensors) for which there is no scientific consensus regarding BP measurement accuracy standards. Altogether, these issues contribute to the widespread availability of clinic and home BP devices with limited or uncertain accuracy, leading to inappropriate hypertension diagnosis, management and drug treatment on a global scale. The most significant problems relating to the accuracy of BP devices can be resolved by the regulatory requirement for mandatory independent validation of BP devices according to the universally-accepted International Organisation for Standardization Standard. This is a primary recommendation for which there is an urgent international need. Other key recommendations are development of validation standards specifically for new BP technologies and online lists of accurate devices that are accessible to consumers and health professionals. Recommendations are aligned with WHO policies on medical devices and universal healthcare. Adherence to recommendations would increase the global availability of accurate BP devices and result in better diagnosis and treatment of hypertension, thus decreasing the worldwide burden from high BP

    Epstein-Barr Virus Nuclear Antigen 3C Facilitates G1-S Transition by Stabilizing and Enhancing the Function of Cyclin D1

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    EBNA3C, one of the Epstein-Barr virus (EBV)-encoded latent antigens, is essential for primary B-cell transformation. Cyclin D1, a key regulator of G1 to S phase progression, is tightly associated and aberrantly expressed in numerous human cancers. Previously, EBNA3C was shown to bind to Cyclin D1 in vitro along with Cyclin A and Cyclin E. In the present study, we provide evidence which demonstrates that EBNA3C forms a complex with Cyclin D1 in human cells. Detailed mapping experiments show that a small N-terminal region which lies between amino acids 130–160 of EBNA3C binds to two different sites of Cyclin D1- the N-terminal pRb binding domain (residues 1–50), and C-terminal domain (residues 171–240), known to regulate Cyclin D1 stability. Cyclin D1 is short-lived and ubiquitin-mediated proteasomal degradation has been targeted as a means of therapeutic intervention. Here, we show that EBNA3C stabilizes Cyclin D1 through inhibition of its poly-ubiquitination, and also increases its nuclear localization by blocking GSK3β activity. We further show that EBNA3C enhances the kinase activity of Cyclin D1/CDK6 which enables subsequent ubiquitination and degradation of pRb. EBNA3C together with Cyclin D1-CDK6 complex also efficiently nullifies the inhibitory effect of pRb on cell growth. Moreover, an sh-RNA based strategy for knock-down of both cyclin D1 and EBNA3C genes in EBV transformed lymphoblastoid cell lines (LCLs) shows a significant reduction in cell-growth. Based on these results, we propose that EBNA3C can stabilize as well as enhance the functional activity of Cyclin D1 thereby facilitating the G1-S transition in EBV transformed lymphoblastoid cell lines

    Windei, the Drosophila Homolog of mAM/MCAF1, Is an Essential Cofactor of the H3K9 Methyl Transferase dSETDB1/Eggless in Germ Line Development

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    The epigenetic regulation of gene expression by the covalent modification of histones is a fundamental mechanism required for the proper differentiation of germ line cells during development. Trimethylation of histone 3 lysine 9 (H3K9me3) leads to chromatin silencing and the formation of heterochromatin by recruitment of heterochromatin protein 1 (HP1). dSETDB1/Eggless (Egg), the ortholog of the human methyltransferase SETDB1, is the only essential H3K9 methyltransferase in Drosophila and is required for H3K9 trimethylation in the female germ line. Here we show that Windei (Wde), the Drosophila homolog of mouse mAM and human MCAF1, is an essential cofactor of Egg required for its nuclear localization and function in female germ line cells. By deletion analysis combined with coimmunoprecipitation, we have identified the protein regions in Wde and Egg that are necessary and sufficient for the interaction between the two proteins. We furthermore identified a region of Egg that gets covalently modified by SUMOylation, which may facilitate the formation of higher order chromatin-modifying complexes. Together with Egg, Wde localizes to euchromatin, is enriched on chromosome 4, and binds to the Painting of fourth (POF) protein. Our data provide the first genetic and phenotypic analysis of a mAM/MCAF1 homolog in a model organism and demonstrate its essential function in the survival of germ line cells

    Lipids, blood pressure and kidney update 2015

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