菲佣的礼物

家中请过一名菲律宾女佣。这名女佣年纪很大,做事认真,只是偶尔贪些小便宜。我们吃剩的菜,或是放久了的水果,甚至旧杂志和旧报纸,她都会打包带回家,每次一大提包。久而久之,母亲有些不悦。母亲是精打细算的人,便对我抱怨：“下次她走时,我要检查她的手提包,不能再让她带走那么多东西。”     

Overcoming the positive-capture strategy in young children: learning about indeterminacy

Two experiments were conducted to examine whether and how 4- and 5-year-olds learn to distinguish determinate from indeterminate evidence. Children were asked to decide whether various patterns of evidence were sufficient to reach unambiguous conclusions. This study replicated the finding that young children tend to use a strategy that, although generally successful, fails on evidence patterns in which a single positive instance co-occurs with an unexplored source of evidence. Experiment 1 demonstrated that this positive-capture strategy is deeply entrenched, even in a meaningful, pragmatic context. With a microgenetic design, Experiment 2 revealed that young children are capable of replacing the positive-capture strategy with a correct strategy when they are exposed to various analogous tasks in several training sessions.     

Evaluating the logic of perspective-taking experiments

In their recent study, Udell, Dorey, and Wynne (in press)[COMP: Ref. is LBE0034. Will have to be updated to (2011) here and in LBE0038, once page nos. are available.] showed that in a begging task, at least in some conditions, dogs as well as wolves preferentially approached a human partner who could see them in contrast to one whose eyes were occluded, and Udell et al. concluded that this success was dependent on the subjects’ experiences with the specific occluder used. Here we argue, however, that since both partners expressed similar attentiveness towards the subjects by calling their names, Udell and colleagues’ conclusion does not refer to the sensitivity of canines to others’ attentiveness, but instead reflects the fact that the animals obeyed a familiar command better in a familiar context than in an unfamiliar one. Moreover, in contrast to Udell et al.’s conclusion, we believe that their data demonstrate that pet dogs can generalize the use of the visibility of human eyes to novel situations, showing a preference towards an attentive partner even if the eyes of the other partner are occluded in a novel way (e.g., having a bucket on his or her head). Finally, after presenting alternative interpretations of the results of the wolves tested by Udell and colleagues, we conclude that there is no evidence that wolves are sensitive to the attentional states of humans.     

An integrated microfluidic array system for evaluating toxicity and teratogenicity of drugs on embryonic zebrafish developmental dynamics

Seeking potential toxic and side effects for clinically available drugs is considerably beneficial in pharmaceutical safety evaluation. In this article, the authors developed an integrated microfluidic array system for phenotype-based evaluation of toxic and teratogenic potentials of clinical drugs by using zebrafish (Danio rerio) embryos as organism models. The microfluidic chip consists of a concentration gradient generator from upstream and an array of open embryonic culture structures by offering continuous stimulation in gradients and providing guiding, cultivation and exposure to the embryos, respectively. The open culture reservoirs are amenable to long-term embryonic culturing. Gradient test substances were delivered in a continuous or a developmental stage-specific manner, to induce embryos to generate dynamic developmental toxicity and teratogenicity. Developmental toxicity of doxorubicin on zebrafish eggs were quantitatively assessed via heart rate, and teratological effects were characterized by pericardial impairment, tail fin, notochord, and SV-BA distance ∕body length. By scoring the teratogenic severity, we precisely evaluated the time- and dose-dependent damage on the chemical-exposed embryos. The simple and easily operated method presented herein demonstrates that zebrafish embryo-based pharmaceutic assessment could be performed using microfluidic systems and holds a great potential in high-throughput screening for new compounds at single animal resolution.     

Definitions of bullying: a comparison of terms used,and age and gender differences,in a fourteen-country international comparison

The study of school bullying has recently assumed an international dimension, but is faced with difficulties in finding terms in different languages to correspond to the English word bullying. To investigate the meanings given to various terms, a set of 25 stick-figure cartoons was devised, covering a range of social situations between peers. These cartoons were shown to samples of 8- and 14-year-old pupils (N = 1,245; n = 604 at 8 years, n = 641 at 14 years) in schools in 14 different countries, who judged whether various native terms cognate to bullying, applied to them. Terms from 10 Indo-European languages and three Asian languages were sampled. Multidimensional scaling showed that 8-year-olds primarily discriminated nonaggressive and aggressive cartoon situations; however, 14-year-olds discriminated fighting from physical bullying, and also discriminated verbal bullying and social exclusion. Gender differences were less appreciable than age differences. Based on the 14-year-old data, profiles of 67 words were then constructed across the five major cartoon clusters. The main types of terms used fell into six groups: bullying (of all kinds), verbal plus physical bullying, solely verbal bullying, social exclusion, solely physical aggression, and mainly physical aggression. The findings are discussed in relation to developmental trends in how children understand bullying, the inferences that can be made from cross-national studies, and the design of such studies.     

Sealing SU-8 microfluidic channels using PDMS

A simple method of irreversibly sealing SU-8 microfluidic channels using PDMS is reported in this paper. The method is based on inducing a chemical reaction between PDMS and SU-8 by first generating amino groups on PDMS surface using N₂ plasma treatment, then allowing the amino groups to react with the residual epoxy groups on SU-8 surface at an elevated temperature. The N₂ plasma treatment of PDMS can be conducted using an ordinary plasma chamber and high purity N₂, while the residual epoxy groups on SU-8 surface can be preserved by post-exposure baking SU-8 at a temperature no higher than 95 °C. The resultant chemical bonding between PDMS and SU-8 using the method create an interface that can withstand a stress that is greater than the bulk strength of PDMS. The bond is permanent and is long-term resistant to water. The method was applied in fabricating SU-8 microfluidi-photonic integrated devices, and the obtained devices were tested to show desirable performance.     

一位少女作家的诞生

<正>1早慧是天生的吗?虽然还是中学生,闵诗睿已经拥有了极其丰富的履历——她是西安市作家协会会员、出过两本书,获得过上百个大小文学奖项,琵琶八级,民族舞五级,还上过几次电视……她的荣誉列满了整整2页A4纸,而我脑海中浮出一个词:早慧。那么,早慧是天生的吗?如何能成长为早慧少女?以下,将会为你一点点揭开答案。     

记得,就是最好的证明

在圣托里尼岛与一位摄影师结为好友。聊天中,他说他偶尔会为一些新婚夫妻拍婚纱照,在拍摄过程中他发现一个很有趣的现象。“每个人都想拍蓝天、大海、教堂的十字尖顶,以及号称世界上最美的日落。我对他们说,再走下去一点,会有很漂亮的巷子和小花,但很少有人愿意去拍。”“为什么?”     

小小乌篷船

<正>1范偶从柳二爷口中确定了茂山也要拜师的消息后,心里气得不行。他掰了片荷叶扇风,然后一屁股坐在柳树下,开始分析起眼前的情况。玉新镇地处江南水乡,历朝历代都有很多水上人家,他们以船为家,船到哪里,就在哪里打鱼、摆渡、做饭和睡觉。这吃饭可是顶要紧的大事,船上的饭菜叫船菜,讲究的人家还做船点。船点是一种由米粉做成的点心。