All Validities are Not Created Equal: Determinants of Variation in SAT Validity Across Schools

Previous research has demonstrated that cognitive test validities are generalizable and predictive of academic performance across situations. However, even after accounting for statistical artifacts (e.g., sampling error, range restriction, criterion reliability), substantial variability often remains around estimates of cognitive test–performance relationships suggesting the presence of additional moderators. In the present study, we examine the sources of institutional variation in Scholastic Aptitude Test (SAT) validity across a sample of 110 institutions. Institutional characteristics moderated the size of SAT validities, such that more selective schools and schools that emphasize traditional assessment techniques (i.e., school records, standardized tests) showed higher SAT validities while schools that were larger and where students demonstrated more financial need, schools that emphasized the usage of alternative assessment techniques (i.e., essays, letters of recommendations, extracurricular activities), and schools that enrolled higher percentages of historically disadvantaged minority students generally exhibited lower SAT validities. Future directions in the understanding of situational influences on SAT–grade point average validities are discussed.     

Benzodiazepine administration prevents the use of error-correction mechanisms during fear extinction

Three experiments examined the effect of systemic administration of the benzodiazepine midazolam on extinction and re-extinction of conditioned fear. Experiment 1 demonstrated that midazolam administration prior to extinction of a conditioned stimulus (CS) impaired that extinction when rats were subsequently tested drug free; however, extinction was spared if rats were extinguished, reconditioned, and re-extinguished under midazolam. Experiment 2 provided a replication of this effect within-subjects; rats were conditioned to two CSs (A and B), extinguished to one (A-), reconditioned to both, and then extinguished/re-extinguished to both stimuli in compound (AB-), under either vehicle or midazolam. On the drug-free test, rats given midazolam froze more to the CS that had been extinguished (B) than the one that been re-extinguished (A). The final experiment examined whether extinction under midazolam was regulated by prediction error. Rats were trained with three CSs (A, B, C) and extinguished to two (A-, C-). These stimuli then underwent additional extinction under midazolam or vehicle, with one CS now presented in compound with the non-extinguished CS (AB-, C-). Rats were then tested for fear of A relative to C. Rats given vehicle showed a deepening of extinction to A relative to C, as is predicted from error-correction models; however, rats given midazolam failed to show any such discrepancy in responding. The results are interpreted to indicate that the drug reduced prediction error during extinction by reducing fear, and rats were able to re-extinguish fear via a retrieval mechanism that is independent of prediction error.     

Critical Conversations on Social Justice in Undergraduate Mathematics

Abstract

This article explores how critical conversations engage undergraduate mathematics faculty in a community of practice that enhances their knowledge about teaching and learning mathematics for social justice. More broadly, critical conversations are defined as a cooperative learning strategy that can be used to identify, explore, and respond to various interests and issues situated across differing values and beliefs. We present a case study of a critical conversation that took place at a 2016 Mathematics for Social Justice workshop organized by a group of junior faculty. Participant reflections situate perspectives that can help novice and experienced instructors design conversations about teaching mathematics for social justice. Specifically, individual and group reflections highlight the importance of: (i) framing and reflecting on the conversation; (ii) exploring implications and content connections; and (iii) identifying barriers. Implications for faculty members and mathematics departments are provided.     

The Relations between Frontal Brain Electrical Activity and Cognitive Development during Infancy

The relations between changes in the scalp-recorded electroencephalogram (EEG) and the development of the ability to perform successfully 2 cognitive tasks attributed to frontal lobe functioning were examined in 13 infants from 7 to 12 months of age. Infants successful in performing the A-not-B task with increasingly longer delays across the second half of the first year of life showed changes in power in scalp-recorded brain electrical activity in the frontal region and an increase in anterior/posterior EEG coherence. Infants with rapid mastery of object retrieval did not differ in frontal EEG development from infants who exhibited the normal developmental progression in object retrieval performance. In a task examining inhibition of reaching to a novel toy, there were no differences in frontal EEG as a function of performance. Results from a cross-sectional sample revealed similar findings. These data confirm work with nonhuman primates on the importance of maturation of frontal cortex in the successful performance on certain tasks (A-not-B), but do not confirm nonhuman primate data on the importance of frontal cortex for other tasks (object retrieval). The data also suggest that the electroencephalogram may be useful as a noninvasive measure of central nervous system development during the first year of life.     

Notes: Evaluation of Physical Education in North Carolina High Schools

Abstract

The purpose of this study was to determine if there were differences in learning to perform a novel motor task between two equated groups: one group was subjected to learning the task immediately following a heavy physical work bout on a bicycle ergometer; the other group was subjected to learning the task with no imposed physical exercise. It was found that the subjects who practiced the stabilometer exercise in a fatigued state performed significantly better than subjects in the control group except for test 4. The experimental group also performed significantly better than the control group during the 5th test which was performed without any fatiguing task. It appears from this study that the fatigue state of the learner had a favorable influence on both performance and learning of certain novel motor skills.     

The effect of acute aerobic exercise on central arterial stiffness,wave reflections,and hemodynamics in adults with diabetes: A randomized cross-over design

BackgroundIndividuals with diabetes have greater central arterial stiffness, wave reflections, and hemodynamics, all of which promote the accelerated cardiovascular pathology seen in this population. Acute aerobic exercise has been shown to be an effective strategy for reducing central arterial stiffness, wave reflections, and hemodynamics in healthy individuals; however, the effects of acute aerobic exercise in reducing these outcomes is not well established in people with diabetes. Recently, implementation of high-intensity interval exercise (HIIE) has shown superior improvements in cardiovascular health outcomes when compared to traditional aerobic exercise. Yet, the effect of HIIE on the aforementioned outcomes in people with diabetes is not known. The purpose of this study was to (i) describe the central arterial stiffness, wave reflections, and hemodynamic responses to a bout of HIIE and moderate-intensity continuous exercise (MICE) in adults with diabetes; and (ii) compare the effects of HIIE and MICE on the aforementioned outcomes.MethodsA total of 24 adult men and women (aged 29–59 years old) with type 1 (n = 12) and type 2 (n = 12) diabetes participated in a randomized cross-over study. All participants completed the following protocols: (i) HIIE: cycling for 4 × 4 min at 85%–95% of heart rate peak (HR_peak), interspersed with 3 min of active recovery at 60%–70%HR_peak; (ii) MICE: 33 min of continuous cycling at 60%–70%HR_peak; and (iii) control (CON): lying quietly in a supine position for 30 min.ResultsA significant group × time effect was found for changes in central systolic blood pressure (F = 3.20, p = 0.01) with a transient reduction for the HIIE group but not for the MICE or CON groups. There was a significant group × time effect for changes in augmentation index at a heart rate of 75 beats/min (F = 2.32, p = 0.04) with a decrease following for HIIE and MICE but not for CON. For all other measures of central arterial stiffness and hemodynamics, no significant changes were observed (p > 0.05).ConclusionA bout of HIIE appears to lead to a greater transient reduction in central systolic blood pressure than the reduction observed following MICE; however, both HIIE and MICE improved augmentation index at a heart rate of 75 beats/min in people with diabetes. There was no significant difference in response to HIIE and MICE in all outcomes. This provides preliminary evidence on the role of HIIE on such outcomes in people with diabetes.     

Weaving a New 'Net: A Mesh-Based Solution for Democratizing Networked Communications

Although the Internet is largely decentralized in its communication and social patterns, its technical and regulatory apparatuses are highly centralized and hierarchical. Consequently, digital communications are vulnerable to a degree of surveillance and censorship that would be unthinkable in traditional social arenas, threatening “Internet freedom” and cyberliberties in both democratic and politically repressed societies. We believe a new architecture is required in order to protect the continuance of civil liberties in networked society. In this article, we propose 10 “social specifications” describing the requirements of such a network, and outline an architecture called MondoNet that meets these specifications using ad hoc, wireless mesh networking technologies. We also address the legal and technical challenges facing the MondoNet project, and anticipate future developments in this field.     

Exploring a Personal Social Knowledge Network (PSKN) to aid the observation of connectivist interaction for high- and low-performing learners in connectivist massive open online courses

This study adds a new perspective to the observations about connectivist interaction behavior in cMOOCs by extending the notion of network building from the perspective of individuals. We explore the possibility of building a learning network named Personal Social Knowledge Network (PSKN) to support in the monitoring of learning performance and interaction in cMOOCs. The sample in this study included 284 preservice teachers and their learning lasted approximately 12 weeks. Data were primarily gathered by PSKN graphs. The results revealed a correlation between connectivist interaction measured by the PSKN (including density structure) and learning performance. The results also revealed differences in connectivist interaction behavior and patterns, indicated by PSKN (densities and structures), for high- and low-performing learners in cMOOCs. The high-performing learners show deeper knowledge interaction and social communication in addition to simple knowledge sharing and social communication. Additionally, as time passed and the PSKN of high-performing learners extended further, their interaction behavior became more complex and their role had gradually changed from “learning” to “teaching” as well as from knowledge acceptance to knowledge creation in cMOOCs.     

Muscle force characteristics of male and female collegiate cross-country runners during overground running

ABSTRACT

Males and females demonstrate unique running mechanics that may contribute to sex-related differences in common running related injuries. Understanding differences in muscle forces during running may inform intervention approaches, such as gait retraining addressing muscle force distribution. The purpose of this study was to compare muscle force characteristics and inter-trial variability between males and females during running. Twenty female and 14 male collegiate cross-country runners were examined. Three-dimensional kinetic and kinematic data were collected during overground running and used to estimate muscle forces via musculoskeletal modelling. Principle components analysis was used to capture the primary sources of variance from the muscle force waveforms. The magnitude of the forces for the hamstrings, gastrocnemius, and soleus muscles were higher across the majority of stance in male runners regardless of footstrike pattern. Males also demonstrated greater inter-trial variability in the timing of the peak gluteus maximus force and the magnitude of local peaks in the gastrocnemius force waveform. Male and female collegiate cross-country runners appear to employ unique lower extremity muscle force characteristics during overground running.     

Compression garments and cerebral blood flow: Influence on cognitive and exercise performance

This study aimed to describe the effect of compression garments on middle cerebral artery blood flow velocity (MCA_v) in relation to cognitive and exercise performance whilst cycling. In a randomised-controlled-cross-over design, 15 well-trained male cyclists were recruited to participate in three identical trials wearing loose fitting shorts (control), low-grade, or medium-grade compression garments. The protocol involved four 8?min increments of cycling at 30%, 50%, 70%, and 85% maximal power output and a 4?km time-trial. Participants undertook a cognitive Stroop task at baseline and at the midpoint of each increment. MCA_v was monitored with Transcranial Doppler Ultrasonography. Mean arterial pressure (MAP) and partial pressure of end-tidal CO₂ (P_etCO₂) were measured throughout. MCA_v, MAP, P_etCO₂, and reaction time of the complex Stroop task were influenced by exercise intensity, but not compression garments. Compression garments significantly affected cognitive accuracy in the complex Stroop task such that low-grade compression appeared to enhance cognitive accuracy in comparison to the control condition at the highest intensity (p?=?.010). Time-trial performance did not differ between the control (338.0?±?17.3 s), low-grade (338.7?±?18.7 s), or medium-grade (342.2?±?19.3 s) conditions (p?=?.114). Compression garments did not affect MCA_v during exercise or time-trial performance, but compression may be beneficial for improved cognitive accuracy during high-intensity exercise. Further research is required to elucidate the potential impact on cognitive performance.