Helping Homeless Families Overcome Barriers to Successful Functioning

The author articulates key stressors in the lives of families who are homeless. These stresses often combine with barriers such as lack of job opportunities and/or insensitive professionals. Strategies for helping homeless families overcome these barriers and related issues are presented.     

What's in It for Me? Incentives,Learning, and Completion in Massive Open Online Courses

This study investigated the distribution of incentives (e.g., certificates, badges) for massive open online course (MOOC) completion, and relationships between incentives and MOOC outcomes. Participants were 779 MOOC students internationally who participated in at least 303 different MOOCs offered by at least 12 providers. MOOC participants most commonly intended to receive, and in actuality received, free and paid course certificates of completion; other incentives (e.g., digital badges, postsecondary credits) were far less common. In addition, MOOC participants' intentions to receive both free and paid certificates were consistently and positively related to perceived learning and course completion, net other factors. (Keywords: massive open online courses, MOOCs, motivation, incentives, microcredentials, certificates of completion)     

The relation of multiple-schedule behavioral contrast to deprivation,time in session,and within-session changes in responding

Pigeons' keypecking was reinforced by food on baseline schedules of multiple variable interval (VI) x VI x and on contrast schedules of multiple VI x VI y. Deprivation of food was varied by maintaining subjects at 75%, 85%, and 95% (+/- 2%) of their free-feeding weights. Positive and negative behavioral contrast were observed. The size of the contrast was not systematically altered by changes in deprivation. Positive and negative contrast were both larger later in the session than they were earlier. Within-session decreases in responding were steeper for the baseline than for the contrast schedules for positive contrast. Within-session decreases were steeper for the contrast than for the baseline schedules for negative contrast. These results were predicted by the idea that different amounts of habituation to the reinforcer during the baseline and contrast schedules contribute to behavioral contrast. The results show that contrast occurs under conditions that reduce the effect of the following component. The results support the assumption that positive and negative contrast are produced by symmetrical theoretical variables.     

Impact of brief or extended extinction of a taste aversion on inhibitory associations: Evidence from summation,retardation, and preference tests

In five conditioned taste aversion experiments with rats, summation, retardation, and preference tests were used to assess the effects of extinguishing a conditioned saccharin aversion for three or nine trials. In Experiment 1, a summation test showed that saccharin aversion extinguished over nine trials reduced the aversion to a merely conditioned flavor (vinegar), whereas three saccharin extinction trials did not subsequently influence the vinegar aversion. Experiment 2 clarified that result, with unpaired controls equated on flavor exposure prior to testing; the results with those controls suggested that the flavor extinguished for nine trials produced generalization decrement during testing. In Experiment 3, the saccharin aversion reconditioned slowly after nine extinction trials, but not after three. Those results suggested the development of latent inhibition after more than three extinction trials. Preference tests comparing saccharin consumption with a concurrently available fluid (water in Experiment 4, saline in Experiment 5) showed that the preference for saccharin was greater after nine extinction trials than after three. However, saccharin preference after nine extinction trials was not greater, as compared with that for either latent inhibition controls (Experiments 4 and 5) or a control given equated exposures to saccharin and trained to drink saline at a high rate prior to testing (Experiment 5). Concerns about whether conditioned inhibition has been demonstrated in any flavor aversion procedure are discussed. Our findings help explain both successes and failures in demonstrating postextinction conditioned response recovery effects reported in the conditioned taste aversion literature, and they can be explained using a memory interference account.     

Learning Is Moving in New Ways: The Ecological Dynamics of Mathematics Education

Whereas emerging technologies, such as touchscreen tablets, are bringing sensorimotor interaction back into mathematics learning activities, existing educational theory is not geared to inform or analyze passages from action to concept. We present case studies of tutor–student behaviors in an embodied-interaction learning environment, the Mathematical Imagery Trainer. Drawing on ecological dynamics—a blend of dynamical-systems theory and ecological psychology—we explain and demonstrate that: (a) students develop sensorimotor schemes as solutions to interaction problems; (b) each scheme is oriented on an attentional anchor—a real or imagined object, area, or other aspect or behavior of the perceptual manifold that emerges to facilitate motor-action coordination; and (c) when symbolic artifacts are introduced into the arena, they may both mediate new affordances for students’ motor-action control and shift their discourse into explicit mathematical re-visualization of the environment. Symbolic artifacts are ontological hybrids evolving from things with which you act to things with which you think. Students engaged in embodied-interaction learning activities are first attracted to symbolic artifacts as prehensible environmental features optimizing their grip on the world, yet in the course of enacting the improved control routines, the artifacts become frames of reference for establishing and articulating quantitative systems known as mathematical reasoning.     

师生冲突的概念界定与分类探究——基于刘易斯·科塞的冲突分类理论

论文通过借鉴和辨析社会学理论中的冲突概念,对师生冲突概念作出界定。根据美国当代社会学家刘易斯·科塞的冲突分类理论,对学校师生冲突进行分类研究。在此基础上提出了三个观点:学校师生冲突的多数属于非现实性冲突;师生结构由紧密走向松散是师生冲突增多的重要原因;师生冲突具有一定的正面功能。     

Land degradation,government subsidy,and smallholders’ conservation decision: the case of the loess plateau in China

Land degradation is one of the severe environmental problems in China. In order to combat land degradation, a soil conservation program was introduced since 2000 to reduce soil erosion by converting slope-cultivated land into forestry and pasture. This paper represents the first systematic attempt to investigate the impact of the soil conservation program on land degradation in the loess plateau. The results indicate that the soil conservation program to convert slope fields into forest or pasture is an effective way to combat soil erosion. However, a subsidy that is higher than profit of land use activity of slope fields before their conversion into forest and pasture is needed to encourage farmers to join the conservation program. A policy measure to encourage and assist farmers to develop sedentary livestock by using crops produced from fields as well as fodder and forage grass from the converted slope fields might contribute to combat soil erosion. Increase in off-farm job opportunities may encourage households to reduce cultivation in slope fields. That implies a policy measure to encourage rural urbanization might contribute to combat soil erosion.     

Space Scale: Models in the History of Science and Students Mental Models

This paper deals with the problem of relating distance and scale by way of alternative models of perception taken from the history of science.The intuitive patterns of modern school children in evaluating the Solar System are then compared with those in the history of science. Immediate experience and intuition by children often contradict scientific understanding. The children in this study, for example, do not see the rays of the Sun as being parallel and ignore the curvature of the Earth. The authors argue that children's understanding of the rays of the Sun as not being parallel as well as their ignoring the curvature of the Earth is due to the limitation resulting from the students' `actual activity zone', and not to their insufficient knowledge. This study makes specific suggestions to broaden the scientifically based `actual activity zone' of students. We suggest that laboratory work based on historical experiments using elementary geometry – as, for example, the determination of the radiusof the Earth by Eratosthenes – promotes a scientific understanding of astronomicalmeasurements....The scale of space and time, which we customarily observe on Earth, and which is part of time, we become aware of the vastness of our universe, we are awed and humbled. But if astronomers spent all their time speculating about the immensity of the cosmos and the prodigious interval of time necessary for the evolution of the stars, their accomplishments would be few. The primary concerns of the astronomer when studying the cosmos are physical and mathematical interpretations of observations, predictions of future observations, and the development and refinement of his instruments for such interpretation and prediction. To help him in the conceptualization of his problem, astronomer may, consciously or unconsciously, visualize a small model representing the cosmic system under investigation. Using this method, we can arrive at an understanding of the relative dimensions of the system and an understanding of the time intervals involved.Shklovskii I.S. and Carl Sagan (1966)Intelligent Life in the Universe     

Yangxueqingnao particles inhibit rat vascular smooth muscle cell proliferation induced by lysophosphatidic acid

Objective: To observe the effect of Yangxueqingnao particles on rat vascular smooth muscle cell (VSMC) proliferation induced by lysophosphatidic acid (LPA). Methods: The amount of3H-TdR (3H-thymidine) admixed in cultured rat VSMC was measured and mitogen-activated protein kinase (MAPK) activity and lipid peroxidation end product malondialdehyde (MDA)content of the VSMC were assayed. Results: 1×10-9, 1×10-8, 1×10-7 mol/L LPA in a concentration dependent manner, induced the amount of 3H-TdR admixed, MAP kinase activity, and MDA content of the cultured rat VSMC to increase. However, 5%, 10%,and 15% Yangxueqingnao serum preincubation resulted in a decrease of 23.0%, 42.0%, and 52.0% (P＜0.01) respectively in the amount of 3H-TdR admixed, a decline in VSMC MAP kinase activity of 13.9% (P＜0.05), 29.6% (P＜0.01), and 48.9% (P＜0.01)respectively, and also, a decrease in MDA content of VSMC of 19.4%, 24.7%, and 43.2% (P＜0.01) respectively, in the 1×10-7mol/L LPA-treated VSMC. Conclusions: LPA activates the proliferation and lipid peroxidation of VSMC in a concentration dependent manner. The LPA-induced VSMC proliferation is related to the activity of MAP kinases, enzymes involved in an intracellular signalling pathway. The results of the present study showed that Yangxueqingnao particles can effectively inhibit LPA-induced VSMC proliferation, MAP kinase activation, and reduce lipid peroxidative lesion.