Fault tolerant software technology for distributed computing system

Issued as Monthly reports [nos. 1-23], Interim technical report, Technical guide books [nos. 1-2], and Final report, Project no. G-36-64

Fault tolerance distributed computing

Issued as Funds expenditure reports [nos. 1-4], Quarterly progress reports [nos. 1-3], and Final report, Project no. G-36-63

Research on reliable distributed computing

Issued as Quarterly funds expenditure reports [nos. 1-4], Quarterly progress reports [nos. 1-4], Final report and Appendix, Project no. G-36-62

Vouchers for Sectarian Schools after Zelman: Will the First Circuit Expose Anti-Catholic Bigotry in the Massachusetts Constitution?

In Zelman v. Simmons-Harris, the U.S. Supreme Court ruled that an Ohio voucher program for Cleveland school children does not violate the Establishment Clause even though the program allows participation by sectarian schools. Within days after the Supreme Court released its decision, many of public education’s advocacy groups publicly expressed disappointment in Zelman’s outcome. Although Zelman settled federal constitutional questions about vouchers, voucher opponents continued fighting in the courts. Much of this post-Zelman litigation involved arguments about the legality of various state constitutional bans against public aid for sectarian education. Scholars have shown that some of these state constitutional provisions—the so-called “Blaine Amendments”—have their roots in 19th century religious prejudice. This article is in four parts. First, it describes the Zelman decision, in which the Supreme Court dismantled a major constitutional roadblock to public assistance for families sending their children to sectarian schools. Second, the article summarizes the scholarship about the Blaine Amendments, which loom now as a major legal obstacle to the implementation of voucher programs in many states. This scholarship shows that the Blaine Amendments are—to say the least—cultural artifacts of 19th century anti-Catholic bigotry. Third, the article briefly reviews two post-Zelman court cases involving “Blaine Amendments”: Bush v. Holmes and Locke v. Davey. In both cases, courts found no evidence of bigotry in the state constitutional provisions that were at issue. Finally, this article exams the case of Wirzburger v. Galvin, in which the First Circuit is considering the constitutionality of a Massachusetts constitutional provision that bars Massachusetts citizens from using the state’s voter initiative process to amend or repeal a 19th century constitutional ban against public funding for sectarian schools. The Massachusetts legislature approved this constitutional ban at a time when it was overwhelmingly dominated by the anti-Catholic Know-Nothing Party. Wirzburger provides the First Circuit an opportunity to weaken a state constitutional provision that was borne of religious intolerance and that wholly nullifies Zelman’s significance in Massachusetts. This article argues that the First Circuit should allow Massachusetts voters the opportunity to amend or repeal their state’s bigoted constitutional bar against public aid for sectarian schools

Stochastic Models Based on Molecular Hybridization Theory for Short Oligonucleotide Microarrays

High density oligonucleotide expression arrays are a widely used tool for the measurement of gene expression on a large scale. Affymetrix GeneChip arrays appear to dominate this market. These arrays use short oligonucleotides to probe for genes in an RNA sample. Due to optical noise, non-specific hybridization, probe-specific effects, and measurement error, ad-hoc measures of expression, that summarize probe intensities, can lead to imprecise and inaccurate results. Various researchers have demonstrated that expression measures based on simple statistical models can provide great improvements over the ad-hoc procedure offered by Affymetrix. Recently, physical models based on molecular hybridization theory, have been proposed as useful tools for prediction of, for example, non-specific hybridization. These physical models show great potential in terms of improving existing expression measures. In this paper we demonstrate that the system producing the measured intensities is too complex to be fully described with these relatively simple physical models and we propose empirically motivated stochastic models that compliment the above mentioned molecular hybridization theory to provide a comprehensive description of the data. We discuss how the proposed model can be used to obtain improved measures of expression useful for the data analysts

Scandium: A key element for understanding Am stars

{\rm Context.} Atomic diffusion is believed to cause the abundance anomalies observed in AmFm stars. However, the detailed process has still not been well-established. For instance, two possible scenarios for the diffusion theory are presently envisaged. They differ mainly by the depth from which the abundance anomalies emanate. The first scenario predicts that the abundances are modified in the superficial regions of the star, just below the hydrogen convection zone. The second scenario predicts that a much deeper extension of the mixing zone exists due to the convection caused by Fe accumulation in regions below the hydrogen convection zone. {\rm Aims.} We calculate much more accurate radiative accelerations of Sc than previously, to better understand the observed abundance anomalies of this element. We believe that it is a key element to use as a diagnostic tool for understanding AmFm stars. {\rmMethods.} The method employed to obtain these radiative accelerations is based on an interpolation from the parameters of the so-called SVP parametric method. {\rm Results.} The radiative accelerations, shown here in a typical Am stellar model, are discussed in light of the observed anomalies of Ca and Sc. Our results suggest that the deeper mixing scenario is not entirely satisfactory: the mixing zone should be deeper than what is predicted by recent models to account for observed Sc underabundances. Our results seem more compatible with the scenario where the abundances anomalies are created in the superficial regions. However, only detailed evolutionary modelling with mass loss and diffusion of all important species, including Ca and Sc, with accurate radiative accelerations, will be able to give more insight into where the source of these anomalies occur in AmFm stars.Comment: 6 pages, 3 figures, accepted for publication in A&

Horizontal Branch evolution, metallicity and sdB stars

Context. Abundance anomalies have been observed in field sdB stars and in nearly all Horizontal Branch (HB) stars of globular clusters with Teff > 11 000K whatever be the cluster metallicity. Aims. The aim is to determine the abundance variations to be expected in sdB stars and in HB stars of metallicities Z \geq 0.0001 and what observed abundances teach us about hydrodynamical processes competing with atomic diffusion. Methods. Complete stellar evolution models, including the effects of atomic diffusion and radiative acceleration, have been computed from the zero age main-sequence for metallicities of Z0 = 0.0001, 0.001, 0.004 and 0.02. On the HB the masses were selected to cover the Teff interval from 7000 to 37000K. Some 60 evolutionary HB models were calculated. The calculations of surface abundance anomalies during the horizontal branch depend on one parameter, the surface mixed mass. Results. For sdB stars with Teff 11 000K in all observed clusters, independent of metallicity, it was found that most observed abundance anomalies (even up to ~ x 200) were compatible, within error bars, with expected abundances. A mixed mass of ~1.E-7 M\odot was determined by comparison with observations. Conclusions. Observations of globular cluster HB stars with Teff > 11 000K and of sdB stars with Teff < 37 000K suggest that most observed abundance anomalies can be explained by element separation driven by radiative acceleration occuring at a mass fraction of ~1.E-7 M\odot. Mass loss or turbulence appear to limit the separation between 1.E-7 M\odot and the surface.Comment: Accepted for publication by A&

A Model for Scattering in Dense Clouds

Lights is almost always detected by its interaction with matter. One of these interaction phenomena is the scattering of light by small particles. A model is developed that estimates the amount of energy that is scattered towards a detector from a beam given the locations of the source, detector and particle. This collection of particles is allowed to be very dense so that a photon scattered from the beam can be scattered several times before leaving the scattering medium. By considering the single-scatter component and multiple-scatter component separately, the model retains the characteristics of both types

La prédiction des contacts avec le tribunal de la jeunesse : utilisation de l’évaluation du comportement par les pairs au début de l’école primaire

This study sets out to verify to what extent the evaluations of the behaviour of children by their peers in first year primary school make it possible to predict those who will eventually end up with an open record at the Juvenile Court. During their first year at school the children are classified according to the following categories : aggressive, socially withdrawn, aggressive-withdrawn, neither aggressive/nor withdrawn (contrast). A total of 992 subjects (493 girls and 499 boys) were evaluated at two different times during the study. The results indicate that the “aggressive-withdrawn” subjects, among the girls, are more likely to have an open record at the Court during the 7 or 8 years after having been evaluated in first year primary school. These findings may indicate that the girls whose behaviour is aberrant are more easily identified by their peers, given the fact that they generally have fewer problems of adaptation than the boys during their first year of school