Educational responses to immigrant students in Madrid

During the last few years, changes in the Spanish educational system have had a far reaching impact. Several factors have been critical: (1) the progressive decentralization of education by the government, now a responsibility of regional governments; (2) the extension of compulsory education to the age of 16; and finally (3) the increase in the number of immigrant students, which has significantly added to the existing cultural diversity. The enrolment of immigrant students in Spanish schools is a relatively recent phenomenon (starting 15 years ago) when compared with other European countries. Madrid is the region in Spain with the largest number of students. As most of these students were born outside of Spain, we cannot yet speak of a second generation. The research described here investigated how the educational system in Madrid confronted the challenge of an increasing number of immigrant students. The institutional response was the Madrid Regional Government’s Compensatory Education Regional Plan. This encompasses several measures, which are described here. After a critical analysis of educational policies pertaining to immigrant pupils, the paper suggests ways of overcoming a purely compensatory approach. Intercultural education plays a key role is such considerations.     

Hurricane Katrina's Impact on African Americans' and European Americans' Endorsement of the Protestant Work Ethic

The Protestant work ethic (PWE), the belief that hard work leads to success, is a quintessentially American belief. The present research addresses a critical gap in psychological research on PWE: can a single, large-scale sociopolitical event (government's response to Hurricane Katrina) produce changes in PWE? We review evidence showing that the salience of Katrina led to a reduction in African Americans' (not European Americans') endorsement of PWE and that this result appears explained by African Americans' greater belief in the government's inadequate response to Katrina victims, who were predominately African American. The implications of differential endorsement of PWE for future expectations of societal treatment, motivation to pursue important goals, and willingness to endorse structural corrections of inequality are discussed.     

Voting in professional associations: The case of the American sociological association revisited

Who votes in ASA elections? This article examines data on voter turnout from two recent presidential contests of the American Sociological Association in an analysis of the determinants of election participation. Extending the 1981 Ridgeway and Moore study of voting dynamics in the ASA, we hypothesize that intraorganizational networks and particular demongraphic characteristics link ASA members to the discipline in a manner analogous to the way such factors operate in the national electorate. On the basis of data compiled from 1985 and 1986 ASA election returns, we find that network factors are the most salient determinants of voting behavior. We conclude that those organizational ties that effectively link members, however directly or indirectly, to the larger Association are the most predictive of propensity to vote.     

Flexible models for non-equidispersed count data: comparative performance of parametric models to deal with underdispersion

AStA Advances in Statistical Analysis - Count data as response variables are commonly modeled using Poisson regression models, which require equidispersion, i.e., equal mean and variance. However,...     

Calibration estimation in dual-frame surveys

Survey statisticians make use of auxiliary information to improve estimates. One important example is calibration estimation, which constructs new weights that match benchmark constraints on auxiliary variables while remaining “close” to the design weights. Multiple-frame surveys are increasingly used by statistical agencies and private organizations to reduce sampling costs and/or avoid frame undercoverage errors. Several ways of combining estimates derived from such frames have been proposed elsewhere; in this paper, we extend the calibration paradigm, previously used for single-frame surveys, to calculate the total value of a variable of interest in a dual-frame survey. Calibration is a general tool that allows to include auxiliary information from two frames. It also incorporates, as a special case, certain dual-frame estimators that have been proposed previously. The theoretical properties of our class of estimators are derived and discussed, and simulation studies conducted to compare the efficiency of the procedure, using different sets of auxiliary variables. Finally, the proposed methodology is applied to real data obtained from the Barometer of Culture of Andalusia survey.     

Application of the Hyper‐Poisson Generalized Linear Model for Analyzing Motor Vehicle Crashes

The hyper‐Poisson distribution can handle both over‐ and underdispersion, and its generalized linear model formulation allows the dispersion of the distribution to be observation‐specific and dependent on model covariates. This study's objective is to examine the potential applicability of a newly proposed generalized linear model framework for the hyper‐Poisson distribution in analyzing motor vehicle crash count data. The hyper‐Poisson generalized linear model was first fitted to intersection crash data from Toronto, characterized by overdispersion, and then to crash data from railway‐highway crossings in Korea, characterized by underdispersion. The results of this study are promising. When fitted to the Toronto data set, the goodness‐of‐fit measures indicated that the hyper‐Poisson model with a variable dispersion parameter provided a statistical fit as good as the traditional negative binomial model. The hyper‐Poisson model was also successful in handling the underdispersed data from Korea; the model performed as well as the gamma probability model and the Conway‐Maxwell‐Poisson model previously developed for the same data set. The advantages of the hyper‐Poisson model studied in this article are noteworthy. Unlike the negative binomial model, which has difficulties in handling underdispersed data, the hyper‐Poisson model can handle both over‐ and underdispersed crash data. Although not a major issue for the Conway‐Maxwell‐Poisson model, the effect of each variable on the expected mean of crashes is easily interpretable in the case of this new model.     

Models of Neurotoxicity: Extrapolation of Benchmark Doses in Vitro

In risk assessment, no observed exposure level (NOAEL) and benchmark dose (BMD) are usually derived either from epidemiological studies in humans or from animal experiments. In many in vitro studies, concentration-effect/response curves have been analyzed using different mathematical models finalized to the identification of EC50. In the present article, we propose a model to fit dose-response curves in vitro. The BMD approach has been used to compare the cell viability (MIT assay) of different rat (C6 and PC12, glial and neuronal, respectively) and human cell lines (D384 and SK-N-MC, glial and neuronal, respectively) after 24-hour exposure to the following neurotoxic substances: manganese chloride (MnCl2), methyl-mercury (Me-Hg), and the enantiomers of styrene oxide (SO). For all rat and human cell lines, the potency of the examined compounds was: MnCl2 < S-SO < R-SO < Me-Hg. A preliminary comparison with in vivo toxicity data for these substances gave rise to consistent results. Whereas a reasonable agreement between in vitro and in vivo data has been found for Mn and styrene oxide, a wide scatter of LOAEL has been reported for Me-Hg and these appear to be either much higher or lower than the BMD for the MIT assay we observed in vitro.