2,512 research outputs found

    Is there a pessimistic bias in individual beliefs ? Evidence from survey data.

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    The aim of this paper is to determine whether individuals exhibit a behavioral bias towards pessimism in their beliefs, in a lottery or more generally in an investment opportunities framework. For this purpose, we design a field survey on a sample of 1,540 individuals aiming at deriving a measure of pessimism from answers to hypothetical scenarios. In the context of our experiment, we observe that individuals are on average pessimistic. We analyze how pessimism is distributed among individuals, in particular in link with gender, age and income. We also analyze how our notion of pessimism is related to more general notions of pessimism already introduced in psychology. We finally estimate the possible impact of this pessimistic bias on the financial markets equilibrium risk premium.pessimism; lottery; judged probability;

    In Search of Professional Dispositions that Yield Cultural Relevance in Primary Grade Pedagogy: A Cautionary Tale of One Kindergarten Teacher

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    Primary grade teachers are challenged to establish firm learning foundations for all children, yet for many teachers cultural diversity makes this a complex pedagogical challenge. It is widely assumed that the success with which teachers meet this challenge is reflected in their dispositions toward diversity, and ultimately toward culturally relevant pedagogy as a professional orientation. This article describes a multi-year study of cultural relevance in early mathematics teaching. Using the case of one kindergarten teacher who exhibited positive dispositions toward cultural relevance, the authors examine factors that seemed to work against its adoption in her pedagogy

    Massively Parallel Sort-Merge Joins in Main Memory Multi-Core Database Systems

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    Two emerging hardware trends will dominate the database system technology in the near future: increasing main memory capacities of several TB per server and massively parallel multi-core processing. Many algorithmic and control techniques in current database technology were devised for disk-based systems where I/O dominated the performance. In this work we take a new look at the well-known sort-merge join which, so far, has not been in the focus of research in scalable massively parallel multi-core data processing as it was deemed inferior to hash joins. We devise a suite of new massively parallel sort-merge (MPSM) join algorithms that are based on partial partition-based sorting. Contrary to classical sort-merge joins, our MPSM algorithms do not rely on a hard to parallelize final merge step to create one complete sort order. Rather they work on the independently created runs in parallel. This way our MPSM algorithms are NUMA-affine as all the sorting is carried out on local memory partitions. An extensive experimental evaluation on a modern 32-core machine with one TB of main memory proves the competitive performance of MPSM on large main memory databases with billions of objects. It scales (almost) linearly in the number of employed cores and clearly outperforms competing hash join proposals - in particular it outperforms the "cutting-edge" Vectorwise parallel query engine by a factor of four.Comment: VLDB201
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