582 research outputs found

    Asymmetry of Information within Family Networks

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    This paper studies asymmetry of information and transfers within 712 extended family networks from Tanzania. Using cross-reports on asset holdings, we construct measures of mis-perception of living standards among households within the same network. We contrast altruism, pressure, exchange and risk sharing as motives to transfer in simple models with asymmetric information. Testing the model predictions in the data uncovers the active role played by recipients of transfers. Our findings suggest that recipients set the terms of the transfers, either by exerting pressure on donors or because they hold substantial bargaining power in their exchange relationships

    A Preliminary Assessment and Identification of theShipwreck Remains Uncovered in 1916 at the World TradeCenter Site in New York City

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    Charred wood timbers of a shipwreck found and rescued in 1916 at the future site of the World Trade Center in Manhattan were origiral/y identified as remains of the TIjger, a Dutch ship that burned in 1614. A swivel cannon marked voc was also found at or near the site in 1967. An.examination 0rthe timbers, preserved in the Museum of the City of New York, suggests they are instead from a vessel of about 55 feet in length built for use on the river or other inland waters, probably by an English shipwright. The . cannon was made in Amsterdam after 1715. This finding does not diminish the significance. of the timbers, .. ~ince very few, if any, remains of other colonial. vessels used on the Hudson River or on othe~ inland waters in the New York City area have been uncovered and preserved for study..

    Bridging the genetical environmental gap in Parkinson's disease through epigenetics

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    Parkinson's Disease (PD) is a progressive neurodegenerative disorder affecting 2% of the population over 60 years old, yet the exact molecular mechanism underlying its pathogenesis remains elusive. PD is a multifactorial disease with genetic and environmental factors intricately associated. Recently, epigenetic mechanisms have been recognized as potential mediators of environmental factors participating in the pathogenesis of PD. Epigenetics refer to the heritable changes in gene expression that do not involve changes to the underlying DNA sequence. Altered epigenetic mechanisms have been attributed to PD, Alzheimer’s and Huntington’s disease. Several studies have shown that DNA methylation, histone modifications and non-coding RNAs mechanisms contribute to the pathogenesis of PD. Accumulation of toxic metals such as manganese and iron, due to abnormal environmental exposure or increased dietary intake, can impact varied components of the epigenetic machinery through free radical formation. Current pharmacological agents only provide symptomatic relief, of which levodopa still remains the gold standard. However, drugs that halt or delay progression of PD are still lacking. In recent years, there has been considerable progress in the development of epigenetic drugs as a novel therapeutic modality in the management of PD. Cell replacement therapy is a promising avenue for the treatment of PD with scientific research making great progress in the development of Induced Pluripotent Stem Cells (iPSCs) to produce midbrain dopamine phenotypes. With direct access to the neurons that are affected in PD, the pace of discovery should speed up and the cure for PD should become an attainable goal.peer-reviewe

    Solving Multi-agent MDPs Optimally with Conditional Return Graphs

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    In cooperative multi-agent sequential decision making under uncertainty, agents must coordinate in order find an optimal joint policy that maximises joint value. Typical solution al- gorithms exploit additive structure in the value function, but in the fully-observable multi-agent MDP setting (MMDP) such structure is not present. We propose a new optimal solver for so-called TI-MMDPs, where agents can only af- fect their local state, while their value may depend on the state of others. We decompose the returns into local returns per agent that we represent compactly in a conditional re- turn graph (CRG). Using CRGs the value of a joint policy as well as bounds on the value of partially specified joint policies can be efficiently computed. We propose CoRe, a novel branch-and-bound policy search algorithm building on CRGs. CoRe typically requires less runtime than the avail- able alternatives and is able to find solutions to problems previously considered unsolvable
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