2,617 research outputs found

    GEEQBOX: A MATLAB Toolbox for Generalized Estimating Equations and Quasi-Least Squares

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    The GEEQBOX toolbox analyzes correlated data via the method of generalized estimating equations (GEE) and quasi-least squares (QLS), an approach based on GEE that overcomes some limitations of GEE that have been noted in the literature. GEEQBOX is currently able to handle correlated data that follows a normal, Bernoulli or Poisson distribution, and that is assumed to have an AR(1), Markov, tri-diagonal, equicorrelated, unstructured or working independence correlation structure. This toolbox is for use with MATLAB.

    Arboreal frogs, tank bromeliads and disturbed seasonal tropical forest

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    We investigated the relationship between arboreal frogs, tank bromeliads and landscape transformation in tropical forests of southeastern Campeche, Mexico. We surveyed frogs in six distinct habitats: slash and burn agriculture, seasonally flooded forest (bajo), aquatic habitats (lagoons and small ponds), second growth upland forest, primary forest and creek habitat using both systematic and non-systematic surveys. The highest species richness of frogs was documented in primary forest and small ponds. In contrast, no frogs were recorded in second growth forest. Similarly, tank bromeliads (Aechmea bracteata) were completely absent from early successional stages and were almost twice as abundant in seasonally flooded forest as in upland forest. The vertical distribution of A. bracteata differed between forest types, and they significantly more abundant in larger diameter trees. We examined 60 tank bromeliads during the peak of the dry season to test their use as refugia by frogs. Approximately 27% of tank bromeliads sampled had arboreal frogs belonging to three species, but 9 species have been recorded as occasional users of bromeliads in the region. There were significantly more frogs on large than on medium-sized bromeliads, and frogs were more abundant on bromeliads higher on host trees, particularly those above 3 m in height. Our results suggest that the loss of tank bromeliads from drier and less structurally complex habitats created by slash and burn agriculture and selective logging results in loss of refugia for arboreal frogs in this seasonal tropical forest. We suggest that Aechmea bracteata be a keystone species in seasonal tropical forest

    Preferences and Heterogeneous Treatment Effects in a Public School Choice Lottery

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    This paper combines a model of parental school choice with randomized school lotteries in order to understand the effects of being assigned to a first-choice school on academic outcomes. We outline a simple framework in which those who place the highest weight on academics when choosing a school benefit the most academically when admitted. Although the average student does not improve academically when winning a school lottery, this average impact conceals a range of impacts for identifiable subgroups of students. Children of parents whose choices revealed a strong preference for academic quality experienced significant gains in test scores as a result of attending their chosen school, while children whose parents weighted academic characteristics less heavily experienced academic losses. This differential effect is largest for children of parents who forfeit the most in terms of utility gains from proximity and racial match to choose a school with stronger academics. Depending on one's own race and neighborhood, a preference for academic quality can either conflict with or be reinforced by other objectives, such as a desire for proximity and same-race peers.

    The Relationship Between Multisensory Learning and Phonemic Awareness and Letter Identification in Kindergarten

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    The purpose of this paper is to evaluate the relationship between multisensory learning and phonemic awareness and letter identification in Kindergarten. The researcher wanted to determine the positive or negative correlation between a multisensory approach to teaching and a student’s overall ability to increase retention capabilities. The seven-week intervention took place in an elementary school located in the Midwest. The intervention participants were six Kindergarten students from the researcher’s classroom. The students were selected based on their past assessment data, specifically regarding letter names/sounds. Instructional methods used were small group, teacher lead, hands on activities that qualified as a multisensory approach. Data was collected in the form of assessments that focused on letter names/sounds, student created journal pages and informal teacher observations that were recorded in shorthand in the teacher journal. Results support the theory that multisensory teaching methods positively affect a student’s ability to increase his/her letter names/sounds identification skills. There is reason to believe that using the multisensory approach to teaching has positive effects and could be replicated in future interventions

    Parental Preferences and School Competition: Evidence from a Public School Choice Program

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    This paper uses data from the implementation of a district-wide public school choice plan in Mecklenburg County, North Carolina to estimate preferences for school characteristics and examine their implications for the local educational market. We use parental rankings of their top three choices of schools matched with student demographic and test score data to estimate a mixed-logit discrete choice demand model for schools. We find that parents value proximity highly and the preference attached to a school's mean test score increases with student's income and own academic ability. We also find considerable heterogeneity in preferences even after controlling for income, academic achievement and race, with strong negative correlations between preferences for academics and school proximity. Simulations of parental responses to test score improvements at a school suggest that the demand response at high-performing schools would be larger than the response at low-performing schools, leading to disparate demand-side pressure to improve performance under school choice.

    Can Good Come From Bad? An Examination of Adversarial Growth in Division I NCAA Athletes

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    The purpose of this study was to examine adversarial growth in a sample of Division I NCAA athletes. Male and female athletes (n = 214) from three universities completed the Posttraumatic Growth Inventory from the perspective of an adversity experienced as a college athlete. The athletes reported positive change at low to moderate levels resulting from their most difficult adversity, and indicated the most improvement in personal strength. Female athletes reported greater spiritual growth, as well as more of a change in their ability to relate to others than their male counterparts. Of the three types of adversities analyzed (i.e., time demands, injury, and the mental and physical stress of sport), athletes who reported time demands as their most difficult adversity exhibited more appreciation for life than athletes who cited the mental and physical stress of sport. These findings are consistent with studies of growth in college student nonathletes (e.g., Anderson & Lopez-Baez, 2008; 2011), and support the notion that college is a pivotal time for personal development (Chickering & Reisser, 1993). Practitioners are advised to consider the potential for adversarial growth in the athletes with whom they work so that they may be able to recognize and facilitate the growth process

    The Effect of Randomized School Admissions on Voter Participation

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    There is little causal evidence on the effect of economic and policy outcomes on voting behavior. This paper uses randomized outcomes from a school choice lottery to examine if lottery outcomes affect voting behavior in a school board election. We show that losing the lottery has no significant impact on overall voting behavior; however, among white families, those with above median income and prior voting history, lottery losers were significantly more likely to vote than lottery winners. Using propensity score methods, we compare the voting of lottery participants to similar families who did not participate in the lottery. We find that losing the school choice lottery caused an increase in voter turnout among whites, while winning the lottery had no effect relative to non-participants. Overall, our empirical results lend support to models of expressive and retrospective voting, where likely voters are motivated to vote by past negative policy outcomes.

    GEEQBOX: A MATLAB Toolbox for Generalized Estimating Equations and Quasi-Least Squares

    Get PDF
    The GEEQBOX toolbox analyzes correlated data via the method of generalized estimating equations (GEE) and quasi-least squares (QLS), an approach based on GEE that overcomes some limitations of GEE that have been noted in the literature. GEEQBOX is currently able to handle correlated data that follows a normal, Bernoulli or Poisson distribution, and that is assumed to have an AR(1), Markov, tri-diagonal, equicorrelated, unstructured or working independence correlation structure. This toolbox is for use with MATLAB
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