Object level physics data replication in the Grid

To support distributed physics analysis on a scale as foreseen by the LHC experiments, 'Grid' systems are needed that manage and streamline data distribution, replication, and synchronization. We report on the development of a tool that allows large physics datasets to be managed and replicated at the granularity level of single objects. Efficient and convenient support for data extraction and replication at the level of individual objects and events will enable for types of interactive data analysis that would be too inconvenient or costly to perform with tools that work on a file level only. Our tool development effort is intended as both a demonstrator project for various types of existing Grid technology, and as a research effort to develop Grid technology further. The basic use case supported by our tool is one in which a physicist repeatedly selects some physics objects located at a central repository, and replicates them to a local site. The selection can be done using 'tag' or 'ntuple' analysis at the local site. The tool replicates the selected objects, and merges all replicated objects into a single single coherent 'virtual' dataset. This allows all objects to be used together seamlessly, even if they were replicated at different times or from different locations. The version of the tool that is reported on in this paper replicates ORCA based physics data created by CMS in its ongoing high level trigger design studies. The basic capabilities and limitations of the tool are discussed, together with some performance results. Some tool internals are also presented. Finally we will report on experiences so far and on future plans

Object Database Scalability for Scientific Workloads

We describe the PetaByte-scale computing challenges posed by the next generation of particle physics experiments, due to start operation in 2005. The computing models adopted by the experiments call for systems capable of handling sustained data acquisition rates of at least 100 MBytes/second into an Object Database, which will have to handle several PetaBytes of accumulated data per year. The systems will be used to schedule CPU intensive reconstruction and analysis tasks on the highly complex physics Object data which need then be served to clients located at universities and laboratories worldwide. We report on measurements with a prototype system that makes use of a 256 CPU HP Exemplar X Class machine running the Objectivity/DB database. Our results show excellent scalability for up to 240 simultaneous database clients, and aggregate I/O rates exceeding 150 Mbytes/second, indicating the viability of the computing models

Prejudice, contact and attitude change in South Africa : a study of integrated schools in the Western Cape

Drawing on the principles of Social Identity Theory and the Contact Hypothesis, this study investigated the relationship between levels of integration and racial prejudice in former Model C, desegregated schools. The sample consisted of 1119 black African, 'Coloured', Afrikaans speaking white and English-speaking white learners from desegregated high schools in Cape Town. ·A pilot study was conducted with 29 learners to establish the face validity and any practical problems, such as ambiguity, that might become evident. The independent variables, Socio-Economic Status, Level of Integration, Racial Identification, Contact at School, Contact Outside School and Contact In-And-Outside School were assessed for their effects on the attitudes of the learners. The dependent measure was the extent of racial prejudice displayed in social distance, subtle racism and ethnic attitudes toward each other. The independent and dependent measures were compiled into a questionnaire which was then administered in situ to the learners by the researcher over a period of six months. Only the responses from black African, 'Coloured', Afrikaans-speaking white and English-speaking white learners were required for the study and the data from other groups was discarded. Multiple regression analysis was used as a statistical technique to analyse the data. Statistically significant results were found for all the dependent measures. There were differences between the intergroup attitudes of black African, 'Coloured', Afrikaans speaking white and English-speaking white learners. The variation in intergroup attitudes could be significantly explained by combinations of Socio-Economic Status (Class), Level of Integration, Racial Identification, Contact at School, Contact Outside School and Contact In-And-Outside School premises. Statistically significant results for Level of Integration were not found for all the dependent measures, indicating that the extent to which schools had been desegregated was not as strong a predictor of intergroup attitudes as was expected. Overall, intergroup contact emerged as a strong predictor of social distance and ethnic attitudes for all groups. Partial support was found for Social Identity Theory as well as for the Contact Hypothesis. The findings indicated a relationship between pleasant intergroup contact, increased social contact outside school and more positive attitudes. Methodological problems associated with the research limit the generalizability of the results

Tales of the Great Jewish Migration: Memory, Assimilation, and Unsettled Matrimony

Between 1880 and 1910, over a million Russian Jews left the Pale of Settlement for the United States in a life-altering wave of immigration. What changes did immigration bring about, and how? To answer these questions, I considered diverse voices of immigrants found in letters, memoirs and short stories, approaching each source as a new layer of interpretation. I found patterns in immigrants\u27 aims, personal commitments and newcomer needs. These patterns affected individuals\u27 decisions to change or preserve tradition. Particularly in the area of matrimony, immigrant partnerships were marked by restless uncertainty

“White Trash” in Literary History: The Social Interventions of Erskine Caldwell and James Agee

This article proceeds from the assertion that most literary scholars dismiss these American authors of the early twentieth century due to aesthetic or social valuations that do not fully take into account what might be gained from an interdisciplinary engagement with their works as social discourse. It then covers some of the historical insights that may be gained from examining their socially engaged texts of the thirties and outlines some of the cultural theoretical lenses that might be most useful in gleaning such insights. Finally, it suggests that the works of Caldwell and Agee are important for understanding both a specific cultural moment and the more general formative impact it has had on current cultural perceptions and modes of scholarly engagement with the rural poor