439 research outputs found

    Occupation-Level Income Shocks and Asset Returns: Their Covariance and Implications for Portfolio Choice

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    This paper develops and applies a simple graphical approach to portfolio selection that accounts for covariance between asset returns and an investor's labor income. Our graphical approach easily handles income shocks that are partly hedgable, multiple risky assets, many periods and life cycle considerations. We apply the approach to occupation-level components of individual income innovations estimated from repeated cross sections of the Current Population Survey. We characterize several properties of these innovations, including their covariance with aggregate equity returns, long-term bond returns and returns on several other assets. Aggregate equity returns are uncorrelated with the occupation-level income innovations, but a portfolio formed on firm size is significantly correlated with income innovations for several occupations, and so are selected industry-level equity portfolios. An application of the theory to the empirical results shows (a) large predicted levels of risky asset holdings compared to observed levels, (b) considerable variation in optimal portfolio allocations over the life cycle, and (c) large departures from the two-fund separation principle.

    Income Shocks, Asset Returns, and Portfolio Choice

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    Field quality in the twin aperture D2 dipoles for LHC under asymmetric excitation

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    Twin aperture D2 magnets are one of the several types of dipoles to be built by BNL for the interaction regions of LHC. To minimize the number of dipole correctors required in the interaction regions, D2 will also be used as part of the steering system. Consequently, the operating fields in the two apertures may differ by up to ~10at 7 TeV operation and ~33at injection in order to compensate for the strengths of the correctors that would otherwise be required. Such asymmetric excitation of the two apertures may induce undesirable field harmonics. The saturation behavior of various harmonics is studied using POISSON and OPERA-2D. It is shown that the changes in harmonics resulting from the anticipated asymmetry are within tolerable limits. (2 refs)

    On the Gains to International Trade in Risky Financial Assets

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    This paper develops and implements a framework for quantifying the gains to international trade in risky financial assets. The framework can handle may agents, many assets, incomplete markets and limited participation in asset markets. It delivers closed-form analytic solutions for consumption, portfolio allocations, asset prices and the gains to trade. We find enormous gains to trade when asset returns are calibrated to observed risk premia and all agents participate in asset markets. The gains-to-trade puzzle is closely related to, but distinct from, the equity premium puzzle. High risk aversion merely alters the form of the gains-to-trade puzzle, but limited participation in asset markets goes a long way towards addressing both puzzles. We also identify three reasons for limited international risk sharing. First, the requirement that asset markets span the space of national output shocks fails in a serious way. Second, for many countries the cost of using financial assets to hedge national output shocks greatly exceeds the benefits. Third, limited asset market participation reduces the feasible gains from international risk sharing.

    HIV-1 Effects on Neuropsychological Performance in a Resource-Limited Country, Zambia

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    Zambia has substantially been affected by the HIV/AIDS epidemic with prevalence rates at 14% in a population estimated at 12 million. Yet, the extent of HIV-associated neurocognitive disorders (HAND) in this population remains to be clearly understood. A series of culturally appropriate neuropsychological (NP) assessments [International HIV Dementia Scale (IHDS), Color Trails Test 1 and 2, Grooved pegboard Test, and Time Gait Test] were used to test the effects of HIV on NP performance of HIV seropositive and seronegative individuals. Twenty-two percent HIV positive individuals ARV naïve met the criteria for IHDS-defined NP impairment. Gender significantly influenced the performance on NP tests with females performing more poorly compared to males. Larger studies that will accommodate gender differences and age are necessary to generate appropriate norms in Zambia in order to better assess the prevalence of HAND in the developing country setting

    Characterization and application of two RANK-specific antibodies with different biological activities.

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    Antibodies play an important role in therapy and investigative biomedical research. The TNF-family member Receptor Activator of NF-κB (RANK) is known for its role in bone homeostasis and is increasingly recognized as a central player in immune regulation and epithelial cell activation. However, the study of RANK biology has been hampered by missing or insufficient characterization of high affinity tools that recognize RANK. Here, we present a careful description and comparison of two antibodies, RANK-02 obtained by phage display (Newa, 2014 [1]) and R12-31 generated by immunization (Kamijo, 2006 [2]). We found that both antibodies recognized mouse RANK with high affinity, while RANK-02 and R12-31 recognized human RANK with high and lower affinities, respectively. Using a cell apoptosis assay based on stimulation of a RANK:Fas fusion protein, and a cellular NF-κB signaling assay, we showed that R12-31 was agonist for both species. R12-31 interfered little or not at all with the binding of RANKL to RANK, in contrast to RANK-02 that efficiently prevented this interaction. Depending on the assay and species, RANK-02 was either a weak agonist or a partial antagonist of RANK. Both antibodies recognized human Langerhans cells, previously shown to express RANK, while dermal dendritic cells were poorly labeled. In vivo R12-31 agonist activity was demonstrated by its ability to induce the formation of intestinal villous microfold cells in mice. This characterization of two monoclonal antibodies should now allow better evaluation of their application as therapeutic reagents and investigative tools

    Muon Colliders

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    Muon Colliders have unique technical and physics advantages and disadvantages when compared with both hadron and electron machines. They should thus be regarded as complementary. Parameters are given of 4 TeV and 0.5 TeV high luminosity \mumu colliders, and of a 0.5 TeV lower luminosity demonstration machine. We discuss the various systems in such muon colliders, starting from the proton accelerator needed to generate the muons and proceeding through muon cooling, acceleration and storage in a collider ring. Problems of detector background are also discussed.Comment: 28 pages, with 12 postscript figures. To be published Proceedings of the 9th Advanced ICFA Beam Dynamics Workshop, AIP Pres
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