179 research outputs found

    Improving small area estimation by combining surveys : new perspectives in regional statistics

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    A national survey designed for estimating a specific population quantity is sometimes used for estimation of this quantity also for a small area, such as a province. Budget constraints do not allow a greater sample size for the small area, and so other means of improving estimation have to be devised. We investigate such methods and assess them by a Monte Carlo study. We explore how a complementary survey can be exploited in small area estimation. We use the context of the Spanish Labour Force Survey (EPA) and the Barometer in Spain for our study

    Developmental trajectories of externalizing behaviors in childhood and adolescence [IF: 3.3]

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    This article describes the average and group-based developmental trajectories of aggression, opposition, property violations, and status violations using parent reports of externalizing behaviors on a longitudinal multiple birth cohort study of 2,076 children aged 4 to 18 years. Trajectories were estimated from multilevel growth curve analyses and semiparametric mixture models. Overall, males showed higher levels of externalizing behavior than did females. Aggression, opposition, and property violations decreased on average, whereas status violations increased over time. Group-based trajectories followed the shape of the average curves at different levels and were similar for males and females. The trajectories found in this study provide a basis against which deviations from the expected developmental course can be identified and classified as deviant or nondeviant

    Co-operative learning and adaptive instruction in a mathematics curriculum

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    The AGO 12 to 16 Project (the acronym AGO stands for the Dutch equivalent of 'Adaptive Instruction and Co-operative Learning') seeks to develop and evaluate a mathematics curriculum which is suitable for mixed-ability groups in secondary education. The research questions we will address here are, first, whether this curriculum is feasible and effective, and, second, what effects, if any, the context variables time and mean cognitive level of the class have on learning. Many mathematics programmes make insufficient allowance for the differences in intellectual ability that exist in mixed-ability classes. In order to change this situation we developed a mathematics curriculum with adaptive qualities. The evaluation of the experimental curriculum was carried out in two stages. During the first stage the curriculum was used at two schools with the aim of investigating the feasibility of the programme. Experience with the implementation of the programme led to some improvements in the experimental materials. By and large the AGO model appeared to be feasible in secondary classrooms. In the second stage, which was on a large scale, the focus was on the effectiveness of the programme. Six hundred students, 13 teachers and six schools were involved in the research. Teachers in the experimental group were trained in AGO methods and in implementing the new AGO curriculum. Teachers in the control groups worked with the existing programme following their usual methods of teaching. The main conclusion of the study is positive. The AGO model as a whole proved to be practical and effective in learning mathematics. The AGO model has a positive effect on the intercept, which means that the mean scores of AGO classes are higher than the mean scores of non-AGO classes. It may be concluded that, on the average, students benefit from learning in AGO classes as compared with non-AGO classes. AGO does not increase or decrease the differences between students in the same class. As expected, positive effects of two context variables were found: (1) the total amount of time spent in class covering the mathematical content and (2) class composition as indicated by the mean pretest score (aptitude) of the class

    “Making voices heard…”: Index on Censorship as Advocacy Journalism

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    The magazine Index on Censorship has sought, since its launch in 1972, to provide a space where censorship and abuses against freedom of expression have been identified, highlighted and challenged. Originally set up by a collection of writers and intellectuals who were concerned at the levels of state censorship and repression of artists in and under the influence of the Soviet Union and elsewhere, ‘Index’ has provided those championing the values of freedom of expression with a platform for highlighting human rights abuses, curtailment of civil liberties and formal and informal censorship globally. Charting its inception and development between 1971 and 1974, the paper is the first to situate the journal within the specific academic literature on activist media (Janowitz, 1975; Waisbord, 2009; Fisher, 2016). In doing so the paper advances an argument which draws on the drivers and motivations behind the publication’s launch to signal the development of a particular justification or ‘advocacy’ of a left-libertarian civic model of freedom of speech

    New Directions in the Development of Population Estimates in the United States?

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    The advent of a continuously updated Master Area File (MAF) following the 2000 census represents an information resource that can be tapped for purposes of developing timely, cost-effective, and precise population estimates for even the smallest of geographical units (e.g., census blocks). We argue that the MAF can be enhanced (EMAF) for these purposes. In support of our argument we describe a set of activities needed to develop EMAF, each of which is well within the current capabilities of the U.S. Census Bureau and discuss various costs and benefits of each. We also describe how EMAF would provide population estimates containing a wide range of demographic (e.g., age, race, and sex) and socio-economic characteristics (e.g., educational attainment, income, and employment). As such, it could largely negate and eliminate the need for many of the traditional demographic methods of population estimation and possibly reduce the number of sample surveys. We identify important challenges that must be surmounted in order to realize EMAF and make suggestions for doing so. We conclude by noting that the idea of the EMAF could be of interest to other countries with MAF files and strong administrative records systems that, like the United States, are facing the challenge of producing good population information in the face of increasing census costs

    A Multilevel Analysis of the Impact of Socio-Structural and Environmental Influences on Condom Use Among Female Sex Workers

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    This study uses multilevel analysis to examine individual, organizational and community levels of influence on condom use among female commercial sex workers (FSW) in the Philippines. A randomized controlled study involving 1,382 female commercial sex workers assigned to three intervention groups consisting of peer education, managerial training, combined peer and managerial intervention and a usual care control group was conducted. The results of the multilevel analysis show that FSWs who work in establishments with condom use rules tend to have a higher level of condom use (β = .70, P < 0.01). Among the different intervention groups, the combined peer and managerial intervention had the largest effect on condom use (β = 1.30, P < 0.01) compared with the usual care group. Using a three-level hierarchical model, we found that 62% of the variation lies within individuals, whereas 24% and 14% of the variation lies between establishments, and communities, respectively. Standard errors were underestimated when clustering of the FSWs in the different establishments and communities were not taken into consideration. The results demonstrate the importance of using multilevel analysis for community-based HIV/AIDS intervention programs to examine individual, establishment and community effects

    Genome Analysis of Planctomycetes Inhabiting Blades of the Red Alga

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    Porphyra is a macrophytic red alga of the Bangiales that is important ecologically and economically. We describe the genomes of three bacteria in the phylum Planctomycetes (designated P1, P2 and P3) that were isolated from blades of Porphyra umbilicalis (P.um.1). These three Operational Taxonomic Units (OTUs) belong to distinct genera; P2 belongs to the genus Rhodopirellula, while P1 and P3 represent undescribed genera within the Planctomycetes. Comparative analyses of the P1, P2 and P3 genomes show large expansions of distinct gene families, which can be widespread throughout the Planctomycetes (e.g., protein kinases, sensors/response regulators) and may relate to specific habitat (e.g., sulfatase gene expansions in marine Planctomycetes) or phylogenetic position. Notably, there are major differences among the Planctomycetes in the numbers and sub-functional diversity of enzymes (e.g., sulfatases, glycoside hydrolases, polysaccharide lyases) that allow these bacteria to access a range of sulfated polysaccharides in macroalgal cell walls. These differences suggest that the microbes have varied capacities for feeding on fixed carbon in the cell walls of P.um.1 and other macrophytic algae, although the activities among the various bacteria might be functionally complementary in situ. Additionally, phylogenetic analyses indicate augmentation of gene functions through expansions arising from gene duplications and horizontal gene transfers; examples include genes involved in cell wall degradation (e.g., κ-carrageenase, alginate lyase, fucosidase) and stress responses (e.g., efflux pump, amino acid transporter). Finally P1 and P2 contain various genes encoding selenoproteins, many of which are enzymes that ameliorate the impact of environmental stresses that occur in the intertidal habitat
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