Fitting the Lognormal Distribution to Surgical Procedure Times*

Minimum surgical times are positive and often large. The lognormal distribution has been proposed for modeling surgical data, and the three‐parameter form of the lognormal, which includes a location parameter, should be appropriate for surgical data. We studied the goodness‐of‐fit performance, as measured by the Shapiro‐Wilk p‐value, of three estimators of the location parameter for the lognormal distribution, using a large data set of surgical times. Alternative models considered included the normal distribution and the two‐parameter lognormal model, which sets the location parameter to zero. At least for samples with n > 30, data adequately fit by the normal had significantly smaller skewness than data not well fit by the normal, and data with larger relative minima (smallest order statistic divided by the mean) were better fit by a lognormal model. The rule “If the skewness of the data is greater than 0.35, use the three‐parameter lognormal with the location parameter estimate proposed by Muralidhar & Zanakis (1992), otherwise, use the two‐parameter model” works almost as well at specifying the lognormal model as more complex guidelines formulated by linear discriminant analysis and by tree induction.     

Threatening Places or Diverse Spaces: Divergent Constructions of Florida Puerto Ricans across Twitter and Newspaper Articles

This study examines constructions of Puerto Ricans across two different media forms: newspaper articles and Twitter. We use Poinciana, Florida, a Central Florida Puerto Rican enclave, as a means to examine these constructions. Because of the high concentration of Puerto Rican residents and unprecedented migration to the area, Poinciana is an ideal community to examine media constructions of a migrant group. Utilizing constructivist grounded theory, we analyze all published newspaper articles (1995–2016) and public Twitter posts (2009–2016) about Puerto Ricans in the region (N = 174). We find newspaper articles construct mostly benign views of Puerto Ricans, reflecting “Happy Talk” diversity discourse, while Twitter constructions present more negative portrayals, generally relating to population size, and often reflecting a racist ideology reminiscent of the Latino Threat Narrative. We conclude by detailing the significance of divergent constructions across media forms during a period of heightened migration, and how the type of media consumed by Puerto Ricans in this community known as “Little Puerto Rico” is likely to influence their perceived level of societal acceptance.     

Analysis of the work of air traffic controllers of the approach control area (APP) of Porto Alegre, Brazil

This article presents a study on the activities of the air traffic controllers of the Approach Control Area (APP) of Porto Alegre, Brazil, in different real scenarios. Based on interviews, questionnaires and the analysis of film of real scenes, the following were identified and analyzed: i) the perceptions of risk and complexity of the different air traffic scenes observed; ii) the cognitive factors (knowledge, strategy and attention dynamics) involved in the task and iii) the perception of the controller's workload. The results showed that the task complexity depends on the weather conditions, the number and type of aircraft in observation and that the controllers perceive the scenes in a similar way irrespective of their time in the profession and the type of control (radar or coordination). Attention is the cognitive factor with the greatest impact on the work and mental demand has the greatest impact on workload followed by time demand. The literature on the controllers work in Brazil is scarce and, therefore, this study aimed to contribute to the understanding of the work in one APP in order to promote future changes in the very problematic Brazilian air traffic system.     

Influence of Age on Transracial Foster Adoptions and Its Relation to Ethnic Identity Development

In the United States, ethnic minorities are disproportionately represented in the foster care system and underrepresented among potential adoptive parents. The need to find permanent homes for foster children has led to an increase in the controversial practice of transracial adoption (TRA), wherein ethnic minority children are placed in adoptive homes with Caucasian parents. While many child welfare scholars and dependency stakeholders support TRA as a positive alternative to foster care, others are concerned that such adoptions may inhibit the ethnic identity development of transracially adopted children. This article documents the large number of ethnic minority children who are adopted through TRA prior to the onset of ethnic identification and how age influences which children are adopted out of foster care. The findings indicate that young ethnic minorities are significantly more likely to be adopted through TRA compared to older children, an effect especially prominent among African Americans. Implications for the child welfare system are discussed.     

Cross-border school enrolment: Associated factors in the U.S.–Mexico borderlands

This paper examines students who live in Mexico but attend school in the U.S., and looks into the factors associated with their decision to study abroad. Based on Mexico’s 2015 Intercensal Survey, cross-border students are described in terms of their number, location, educational level and socioeconomic characteristics. Subsequently, the study estimates probit models to analyze the factors associated with studying in the United States. Cross-border students are mainly U.S.-born and concentrated in Tijuana and Ciudad Juárez. The probability of being a cross-border student is positively associated with age, household income and having a household member who was born in the U.S. or is a cross-border worker. Cross-border students come from high-income households with strong ties to the United States. The decision to study in the U.S. is likely taken due to the higher quality of the country’s education system and to facilitate an eventual transition into the U.S. labor market.     

The possibility of group choice: pairwise comparisons and merging functions

Preferences in Arrow’s conditions are ordinal. Here we show that when intensity of preference represented by reciprocal pairwise comparisons is considered, it is always possible to construct an Arrowian social welfare function using a two-stage social choice process. In stage 1, the individual pairwise relations are mapped into a social pairwise relation. In stage 2, the social pairwise relation is used to generate a cardinal ranking and this ranking is then used to select a particular member of the choice set.     

Powerlessness y Participacion Politica Convencional

Este artículo presenta una aproximación a la participación política convencional desde una perspectiva psicosocial. Partiendo de una crítica al confusionismo y escaso valor predictivo proporcionado por las variables sociodemográficas, se analiza la contribución del constructo de «powerlessness» a la explicación de la conducta de voto. Se discute la multidimensionalidad del constructo y sus posibilidades para la comprensión de la problemática de la abstención electoral.     

On the Run Length of a State-Space Control Chart for Multivariate Autocorrelated Data

The literature on statistical process control (SPC) describes the negative effects of autocorrelation in terms of the increase in false alarms. This has been treated by the individual modeling of each series or the application of VAR models. In the former case, the analysis of the cross correlation structure between the variables is altered. In the latter, if the cross correlation is not strong, the filtering process may modify the weakest relations. In order to improve these aspects, state-space models have been introduced in multivariate statistical process control (MSPC). This article presents a proposal for building a control chart for innovations, estimating its average run length to highlight its advantages over the VAR approach mentioned above.