Reassessing Schoenfeld residual tests of proportional hazards in political science event history analyses

An underlying assumption of proportional hazards models is that the effect of a change in a covariate on the hazard rate of event occurrence is constant over time. For scholars using the Cox model, a Schoenfeld residual-based test has become the disciplinary standard for detecting violations of this assumption. However, using this test requires researchers to make a choice about a transformation of the time scale. In practice, this choice has largely consisted of arbitrary decisions made without justification. Using replications and simulations, we demonstrate that the decision about time transformations can have profound implications for the conclusions reached. In particular, we show that researchers can make far more informed decisions by paying closer attention to the presence of outlier survival times and levels of censoring in their data. We suggest a new standard for best practices in Cox diagnostics that buttresses the current standard with in-depth exploratory data analysis

EL SILENCIO DE LOS PERSONAJES ANÓNIMOS, EN Y MATARAZO NO LLAMÓ..., DE ELENA GARRO

La obra más querida de Elena Garro junto con Los recuerdos del porvenir (1963) es la novela Y Matarazo no llamó..., publicada en 1991 aunque está fechada en 1960. Dicha novela hace referencia a la huelga ferrocarrilera mexicana de 1959, cuyas alusiones se encuentran desde el principio del texto. El presente artículo parte de una pregunta: ¿por qué Elena Garro elige como protagonista a un personaje ficticio y ordinario de clase media, aunque el tema tiene como base un hecho histórico de gran importancia en la historia de la democracia en México? A medida que se desarrolla el relato, las referencias al silencio se hacen más frecuentes e intensas, las cuales analizaremos en tres apartados conforme avanza el silencio. El silencio aparece como elemento clave para describir a los personajes a partir de que los huelguistas visitan a Eugenio y le piden su ayuda, y después de que le dejan a un herido desconocido en su casa. El silencio predomina en el ambiente de la narración. Este silencio que se intensifica deviene en la muerte de los protagonistas y en las noticias donde ni siquiera se mencionan sus nombres. Eugenio piensa en los otros personajes sin nombre que se hallan en una situación igual que la suya. En ese momento, la anonimia que sería una finalización del silencio que se les impone a las víctimas de la violencia se convierte radicalmente en el código para la compenetración y la solidaridad

La polisemia del título Cuatro monólogos monstruosos, de Andrés Neuman, a través de los silencios del discurso.

Una estrategia para interpretar el microcuento, género al que pertenece Cuatro monólogos monstruosos, es adivinar, imaginar y rellenar los huecos que existen en las narraciones, según declaraciones del propio autor, Andrés Neuman. El silencio que examinamos en el texto coincide con lo que el narrador no dice, oculta o niega, y a veces con la intertextualidad con otro cuento. Al descifrar lo no dicho, los lectores encuentran el deseo oculto de los narradores-personajes en el fondo de la historia, que es un deseo de desafiar y confrontar la normativa represiva de la sociedad. A ese fenómeno lo denominaremos ‘monstruosidad’, recurriendo al concepto de Gabriel Giorgi que considera lo monstruoso como posibilidad y potencia alternativas a la norma que restringe a la sociedad, en vez del mero título de extraño o insólito. Los cuatro narradores-personajes son el recolector de basura que abre las bolsas que tira la gente, el ahogado que teme la tortura de los desconocidos que lo encuentran, el asesino que ha matado a un niño por impulso y el risueño cuya risa le impide suicidarse cada vez que lo intenta. Al principio, el título del texto se entendería en sentido general de lo monstruoso por las características raras que tienen estos cuatro narradores-personajes. Pero si consideramos el concepto de monstruosidad desde otra perspectiva, analizando los silencios del texto, encontraremos que la frase ‘monólogos monstruosos’ remite a otro significado, por tratarse de un título polisémico, según demostraremos en el presente artículo

The Effects of a Weight Loss Program Focusing on Maternal Education on Childhood Obesity

PurposeChildhood obesity is a matter of great concern because of its negative health and social consequences. We examined the effect of a weight control program focusing on maternal education on childhood obesity, given that the incidence of obesity is greatly affected by parents.MethodsA two-group pre-test/post-test design was used. Participants consisted of 65 obese children and their mothers. The children were fourth- to sixth-grade elementary students who did not currently receive any therapy for weight loss. The children and their mothers were randomly assigned to either an experimental (n = 32) or a control group (n = 33). The 8-week intervention for mothers included one-time group education, three-time phone counseling, and four-time fliers regarding obesity management. Four outcomes (self-control, obesity index, abdominal circumference, and body fat percentage) were measured before and after the intervention. Chi-squared test or t test was used to test homogeneity between the two groups. Analysis of covariance was used to test the intervention effects.ResultsAfter the intervention was completed, the level of self-control was significantly heightened and obesity levels in the other three outcomes were greatly lowered in the experimental group when compared with the control group.ConclusionDue to strong maternal effects on children's weight control, mothers' active participation must be encouraged in order to resolve childhood obesity

The effects of team-based learning on nursing students’ learning performance with a focus on high-risk pregnancy in Korea: a quasi-experimental study

Purpose The purpose of this study was to examine the effects of team-based learning (TBL) on nursing students’ communication ability, problem-solving ability, self-directed learning, and nursing knowledge related to high-risk pregnancy nursing. Methods This quasi-experimental study used a nonequivalent control group pretest-posttest design. The participants were 91 nursing students allocated to an experimental group (n=45) and a control group (n=46). The experimental group received TBL lectures three times over the course of 3 weeks (100 minutes weekly) and the control group received instructor-centered lectures three times over the course of 3 weeks (100 minutes weekly). Data were collected by questionnaires from September 10 to November 8, 2019. Data were analyzed using the chi-square test, paired t-test, and independent t-test. Results After the intervention, the mean scores of problem-solving ability (t=–2.59, p=.011), self-directed learning (t=4.30, p<.001), and nursing knowledge (t=3.18, p=.002) were significantly higher in the experimental group than in the control group. No significant difference in communication ability was found between the experimental and control group (t=1.38, p=.171) Conclusion The TBL program was effective for improving nursing students’ problem-solving ability, self-directed learning, and nursing knowledge. Thus, TBL can be considered an effective teaching and learning method that can improve the learning outcomes of high-risk pregnancy nursing in women’s health nursing classes. The findings suggest that TBL will be helpful for future nursing students to develop the nursing expertise necessary for providing nursing care to high-risk pregnant women

Compressive performance of 50 MPa strength concrete-filled square and circular tube (CFT) columns using recycled aggregate

[EN] Recycled aggregate is an environmentally self-sustainable solution that can reduce construction waste and replace natural aggregates. However, there is a disadvantage in concrete such as initial strength drop and long-term strength development. Therefore, the interaction effect of the two materials can be expected by filling the cyclic aggregate concrete in the CFT column. In order to develop a concrete with compressive strength of 50 MPa as a recycled aggregate, we carried out a mixing experiment and fabricated 18 specimens to confirm the compressive behavior of a RCFT (Recycled Concrete Filled Tube) column that can be applied to actual buildings. Variable is the shape and thickness of steel pipe, concrete strength and mixing ratio, and coarse aggregate and fine aggregate are all used as recycled aggregate. The optimum mixing ratio for recycled aggregate concrete to be filled in the CFT filled steel pipe was found through three concrete preliminary mixing experiments. In addition, the compression test of the RCFT column was carried out to observe and analyze the buckling shape of the CFT column. Based on the analysis of the buckling configuration and the experimental data, the load-displacement curves of the specimens were drawn and the compressive behavior was analyzed.Choi, S.; Choi, WH.; Lee, K.; Ryoo, J.; Kim, S.; Park, Y. (2018). Compressive performance of 50 MPa strength concrete-filled square and circular tube (CFT) columns using recycled aggregate. En Proceedings of the 12th International Conference on Advances in Steel-Concrete Composite Structures. ASCCS 2018. Editorial Universitat Politècnica de València. 305-313. https://doi.org/10.4995/ASCCS2018.2018.7021OCS30531