1,721,160 research outputs found
Social Integration of Second Generation Students in the Italian School System
Full text linkCultural divides and prejudices complicate the processes of integration
and acculturation of migrant families living in a foreign country. Evaluating
the impact of such phenomenon can be crucial for social stability and
policy making. In this context, the education system has a leading role in fostering
and attaining social integration, in particular when it comes to younger
sections of the migrant population. In this work, we propose a method for the
construction of a quantitative indicator capturing social integration of second
generation students in the Italian school system according to areas dened
by nationality of the students and administrative region in which they attend
school. The indicator, based on survey data, is estimated following a
2-step methodology. In the rst step, following alternatively a proxy variable
approach or a Latent variable model approach, we choose an individual qualitative
variable capturing social integration at the unit level and we compute
a rst raw estimate of the indicator as the proportion of highly integrated
students in each area. In the second step, we make use of two alternative
small area models to improve the estimates, dealing with missing values, low
sample size in smaller domains and high variability. At the end, the 2-step
methodology results in 4 alternative versions of a synthetic indicator of social
integration, that can be used to rank nationalities and administrative regions
Resampling procedures for sample surveys
No full textThis article discusses some resampling techniques that have found widespread
application in survey sampling, especially when inference is conducted on the variance of
parameter estimates. The following methods are illustrated in a complex survey perspective:
random group, balanced repeated replications (or balanced half-samples), jackknife,
and the bootstrap
L'indagine sui consumi: alcune verifiche su proposte di campionamento alternative
Full text linkThe paper presents some changes on the strategies adopted by Istat in the data collection on consume. Specifically, it examines the changes concerning the registration period of consume, the stratification of the primary sampling units (PSU), the rotation schemes for the PSUs, the sampling size. Moreover, it considers the sampling estimators and some simulations about the inclusion order of PSUs
Estimating the biodiversity of a system with covariates and dependence structures
No full textEntropy is widely used in ecological and environmental studies, with data
often presenting complex interactions. Difficulties arise when the interest is to link
such measure to available covariates or data dependence structures, as all existing
approaches to entropy estimation assume independence. We focus on improving the
estimation of the probabilities of the species in biodiversity studies, accounting for
any data dependence and correlation. Estimating entropy is then straightforward and
may be an informative index of a system’s biodiversity. An application is presented
about the biodiversity of rainforest tree data
Gli statistici italiani e la "questione della razza"
Full text linkRicostruzione del contributo di statistici e demografi alla preparazione dei provvedimenti discriminatori del 1938 e degli effetti di questi sull'articolazione accademica e scientifica della disciplina
Special Issue on "Spatial data methods for Ecological and Environmental processes". Environmetrics
No full textEffect of hypophysectomy and growth hormone on tryptophan and serotonin metabolism
No full textThe presented study reports data on brain serotonin (5 HT) metabolism in 2 experimental conditions which have in common a lack of pituitary growth hormone (GH) and discusses also the effect of a GH replacement therapy. In hypophysectomized female rats or genetically dwarf mice, which have a more selective deficiency of GH, brain tryptophan (TP) and 5 hydroxyindoleacetic acid (5 HIAA) concentrations were significantly higher than in age matched controls. Brain levels of 5 HT were practically unchanged. A GH replacement therapy resulted in both hypophysectomized rats and dwarf mice in a significant reduction of brain TP and 5 HIAA concentrations. These results suggest that GH may exert an inhibitory action on 5 HT metabolism. Consonant with this view are the preliminary findings that in 7 individuals with elevated plasma GH levels for acromegaly, plasma TP levels were lower than in control subjects
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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