The rewarding effects of number and surface area of food in rats

Visual cues have an important role in food preference for both rats and humans. Here, we aim to isolate the effects of numerosity, density, and surface area on food preference and running speed in rats, by using a forced-choice maze paradigm. In Experiment 1, rats preferred and ran faster for a group of multiple smaller pellets rather than a single large pellet, corroborating previous research (Capaldi, Miller, & Alptekin Journal of Experimental Psychology: Animal Behavior Processes, 15(1), 75–80, 1989). Further experiments tested the prevailing hypothesis that multiple food pieces are more reinforcing because they occupy a larger surface area. Experiment 2 controlled for numerosity by utilizing a continuous food: mashed potatoes flattened to cover a larger surface area or rounded into a ball. The rats preferred and ran faster for the flattened potatoes, suggesting surface area plays a role in quantity estimations. Finally, in Experiment 3, rats displayed no preference or difference in running speed between a group of scattered and clustered pellets when number of pellets were kept constant. Taken together, these results suggest that density has an important role in food perception—that is, the rewarding effect of higher numerosity or larger surface area is removed when the food does not fill out the entire space. Alternative explanations and implications for human diet are discussed.     

软弱路基采用深层搅拌桩和压密注浆法处理的加固技术

介绍深层搅拌桩和压密注浆法加固技术在镇江市政工程中的应用,重点阐述这两种加固方法的机理、施工方法及质量检测.     

天赋与才能的辩证思考

天赋对才能的有利或不利,是有限的、可变的、非决定性的,而勤奋努力对才能的作用则是巨大的、稳定的、决定性的。天赋优异并不能代替勤奋,而勤奋却可以弥补天赋不足。所谓“上智与下愚不移”,乃是无视人的主观能动性的形而上学观点,两者不仅可移,而且能够互相转化,“移”和“转化”的最有力的杠杆,就是勤奋。     

我国教育网站易访问性的现状及其设计

教育网站是网络教育的应用平台,教育网站的易访问性是不同学习者获取信息和达到同一学习目标的必要条件。本文介绍了教育网站易访问性和各类有特殊访问需求的学习者的关系,分析了我国教育网站易访问性的现状和主要问题,并探讨了如何改进教育网站易访问性的设计。     

Fighting for Desired Versions of a Future Self: How Young Women Negotiated STEM-Related Identities in the Discursive Landscape of Educational Opportunity

In this article, we investigate how the national imperative to increase opportunities for young women of color in science, technology, engineering, and mathematics (STEM) and to broaden their participation was taken up locally at two high schools in one school district. Using ethnographic and longitudinal data, we focus on four young women of color (two at each school) as they negotiated STEM-related identities in the discursive and practice contexts of their lives at school. Using Holland and Lave’s concept of history in person, we view the young women as fighting for particular versions of a future self while entangled in discursive and social relations that threatened to position them differently than they wished to be. We find that their fight for future selves was not—for them—with the national narrative about women of color in STEM but with local school narratives that negatively positioned students of color more broadly and remained silent on issues of gender, the intersection of gender and race, and the implications for STEM. High school success in STEM came as a hopeful but potentially fragile byproduct of struggles to differentiate themselves from people like them (other Blacks, Latinas, the poor). Implications of these findings are discussed.     

An adaptive strategy for controlling chaotic system

This paper presents an adaptive strategy for controlling chaotic systems. By employing the phase space reconstruction technique in nonlinear dynamical systems theory, the proposed strategy transforms the nonlinear system into canonical form, and employs a nonlinear observer to estimate the uncertainties and disturbances of the nonlinear system, and then establishes a state-error-like feedback law. The developed control scheme allows chaos control in spite of modeling errors and parametric variations. The effectiveness of the proposed approach has been demonstrated through its applications to two well-known chaotic systems: Duffing oscillator and Rössler chaos.     

师专开设《精细化工实验》方式的探讨

探讨了师专开设《精细化工实验》分别与《有机化学实验》及教师的科研相结合的方式，应用于教学产生了良好的效果．     

《孤独者》与鲁迅的人生选择

本文通过《狐独者》文本寻找鲁迅人生道路的转折点．认为《孤独者》是作者对专制意识形态传播和生产的最深处家族制度的否定，并在探讨知识分子与权力阶层的关系的基础上，于内心深处进行了一次“成为自己”的生存体验，从而确定了鲁迅此后与黑暗抗争的生存方式。     

专业化:21世纪成人教育管理队伍建设的必然趋势

专业化,是21世纪社会分工、职业分化的结果,是社会各行各业发展的趋势和潮流.成人教育管理队伍的专业化不仅是社会发展的需求,也是成人教育工作和成人教育管理者个体发展的要求.本文从理论上对成人教育管理队伍专业化内涵和标准进行了探悉,并从宏观、中观、微观三个角度提出了几点成人教育管理队伍专业化的策略,以期促进我国成人教育管理专业的进程.