Successive negative contrast in the consummatory responding of didelphid marsupials

In a consummatory experiment patterned after previous work with rats and goldfish, successive negative incentive contrast was sought in didelphid marsupials of two species (Lutreolina crassicaudata andDidelphis albiventris). Half of the subjects of each species were trained from the outset with a 32% sucrose solution and shifted occasionally to a 4% sucrose solution; the rest, which served as controls, were trained only with the 4% solution. The positive results obtained (less response to the 4% solution in the shifted subjects than in the controls) fit the hypothesis, based on comparative work with descendants of older vertebrate lines, that the mechanism of successive negative incentive contrast evolved in a common reptilian ancestor of birds and mammals.     

The relationship of teachers' conceptions of mathematics and mathematics teaching to instructional practice

Case studies were conducted to investigate the conceptions of mathematics and mathematics teaching held by three junior high school teachers. Examination of the relationship between conceptions and practice showed that the teachers' beliefs, views, and preferences about mathematics and its teaching played a significant, albeit subtle, role in shaping their instructional behavior. Differences among the teachers in their conceptions and practices are explained followed by a discussion of properties of their conceptual systems.This paper is based on the author's doctoral dissertation which was directed by Professor Thomas J. Cooney of the University of Georgia and was partly supported by a grant from San Diego State University. I wish to express my appreciation to the teachers who participated in the study and their administrators.     

Curriculum and Society: Rethinking the Link

This article argues that the link between educational curricula and society as a whole has become critically uncertain. This crisis is linked to a number of factors related to the post-modern world view, including: the disappearance of grand utopian social visions of the kind that used to underpin educational policy; the lack of adequate theoretical tools; and the way in which academics are exposed to a multitude of different cultural norms. The author argues that this situation calls for a fundamental re-thinking of the link between curriculum and society, based on a more flexible and pluralistic approach.     

The Effectiveness of Concept Maps in Teaching Physics Concepts Applied to Engineering Education: Experimental Comparison of the Amount of Learning Achieved With and Without Concept Maps

A study was conducted to quantify the effectiveness of concept maps in learning physics in engineering degrees. The following research question was posed: What was the difference in learning results from the use of concept maps to study a particular topic in an engineering course? The study design was quasi-experimental and used a post-test as a measuring instrument. The sample included 114 university students from the School of Industrial Engineering who were divided into two equivalent homogeneous groups of 57 students each. The amount of learning attained by the students in each group was compared, with the independent variable being the teaching method; the experimental group (E.G.) used concept maps, while the control group (C.G.) did not. We performed a crossover study with the two groups of students, with one group acting as the E.G. for the topic of optical fibers and as the C.G. for the topic of the fundamental particles of matter and vice versa for the other group. For each of the two topics studied, the evaluation instrument was a test of 100 dichotomous items. The resulting data were subjected to a comparative statistical analysis, which revealed a significant difference in the amount of learning attained by the E.G. students as compared with the C.G. students. The results allow us to state that for the use of concept maps, the average increment in the E.G. students’ learning was greater than 19 percentage points.     

English language learners with reading-related LD: linking data from multiple sources to make eligibility determinations

Results are reported for an exploratory study of eligibility decisions made for 21 Spanish-speaking English language learners (ELLs) with learning disabilities (LD) and no secondary disabilities who received special education support in reading. Eligibility determinations by an expert panel resulted in decisions that differed significantly from those of school multidisciplinary teams. The panel agreed that some students appeared to have reading-related LD (n = 5) but also identified students that they believed had disabilities, but not necessarily reading-related LD (n = 6). Another group of students (n = 10) had learning problems that the panel believed could be attributed to factors other than LD or for whom substantive additional data would be required to validate eligibility. Issues associated with referral, assessment, and eligibility determinations for ELLs are discussed, and recommendations for improving practice are offered, with an emphasis on the importance of linking data from multiple sources when deciding whether ELLs qualify for special education.     

Serial position effects in social transmission of food preference: Retention/demonstration intervals

The effects of retention and demonstration intervals on serial position were evaluated in two experiments with Long-Evans rats. A list of 3 demonstrators that had eaten one of three flavored foods was presented to naive observers. In Experiment 1, there were four groups, three groups with a retention interval compared with one group with a zero retention interval or no retention interval. In Experiment 2, the demonstration interval was reduced. Intervals of 15, 5, 2, and 1 min were used. In Experiment 1, primacy decreased gradually in the four groups as the retention interval was increased in duration. In Experiment 2, primacy also decreased gradually, and recency occurred with the 1-min demonstrator interval. The increase in the duration of the retention interval reduced primacy. The reduction in the duration of the demonstration interval decreased primacy and produced recency.     

Una Perspectiva Crítica Racial de la Opresión Lingüística Desde el Lente de Voces Chicanas

En este artículo los autores recurren a voces de personajes chicanos para analizar y discutir la opresión lingüística del méxico americano durante las décadas de 1920 a 1960. Utilizando la teoría racial crítica y la teoría latina del racismo (CRT y LatCrit por sus siglas en inglés) los autores hacen referencia específica a pasajes, documentos históricos y piezas de la literatura para argumentar que cuestiones de poder y racismo han impactado la restricción en el uso del idioma español en los Estados Unidos. De manera específica, se hace referencia a los castigos sufrido por varias generaciones de hispanoparlantes.

In this article, the authors analyze and discuss the linguistic oppression faced by Mexican-Americans from the 1920s to the 1960s as narrated by Chicano voices. Critical Race Theory and Latino/a Critical Race Theory permeate the argument that issues of power and racism have impacted the use of Spanish in the United States. This oppression is reflected in historical documents, passages, and segments of Chicano literature. Specifically, the article describes instances of punishment suffered by several generations of Spanish speakers.     

Re-imagining active learning: Delving into darkness

Ample attention is being paid in the higher education literature to promoting active learning among students. However, critical examination of educational purposes and ends is largely lacking in this literature on active learning. In expanding this debate, we consider it important to ask: About what substantive matters are students to be active? To what end is this activity directed, especially beyond gaining skills and competences within a unit of work or course? In this article, we critique and extend the conceptualisation of active learning. In particular, we discuss dimensions that are neither readily visible nor instrumental, which are overlooked in much of this literature. In doing so, we explore features and potential consequences of such an expanded conceptualisation. Drawing from educational philosophy and, in particular, existential philosophies, we show that active learning may also be partly invisible, unfocused, unsettling, and not at all instrumental—sometimes even leaving the learner more confused and (temporarily) incompetent. However, such forms of undisclosed or ‘dark’ learning, we conclude, are necessary and even vital counterparts for the forms of active learning that flood higher education curricula today.     

Identification,collection and consumption of weeds and wild vegetables in Mexican communities: institutionalized local ancestral indigenous knowledge as ecological literacy,place and identity

Cultural Studies of Science Education - This paper sets forth the idea that a critical aspect of the socialization process of Mexican communities is to maintain and carry-out traditional knowledge...     

Assessing Fat Mass of Adolescent Swimmers Using Anthropometric Equations: A DXA Validation Study

Purpose: The aim of the present study was to determine which of the published anthropometric equations is the most appropriate to estimate body-fat percentage (BF_%) in adolescent swimmers. Method: Eighty-eight swimmers (45 boys, 43 girls) participated in this study. Following the recommendations of the International Society of the Advancement of Kinanthropometry, biceps, triceps, subscapular, iliac-crest, supraspinale, front-thigh, and medial calf skinfold thicknesses were measured. Waist, hip, midthigh, calf, relaxed arm, and arm flexed and tensed girths were also registered. BF_% was measured with dual-energy X-ray absorptiometry (DXA) to obtain the reference value. Existing anthropometric equations were applied, and BF_% results obtained from anthropometric equations were compared to DXA BF_% results with the modified Bland-Altman. Results: The Flavel, Durnin-Rahaman-Siri, and Durnin-Rahaman-Brozek were the only equations that did not demonstrate statistically significant differences when compared with DXA. Conclusion: The present study showed that the best anthropometric equation from existing literature to estimate BF_% in swimmers is that proposed by Durnin-Rahaman (independently of applying the Siri or Brozek equation).