Joint Attention,Self‐Recognition,and Neurocognitive Function in Toddlers

Recent studies have attempted to understand the processes involved in joint attention because of its relevance to both atypical and normal development. Data from a recent study of young children with autism suggests that performance on a delay nonmatch to sample (DNMS) task associated with ventromedial prefrontal functions, but not an A‐not‐B/delayed response task associated with dorsolateral prefrontal cortex, was related to joint attention skills (Dawson et al., 2002). Recent research also suggests that joint attention is associated with dorsalmedial brain systems linked to self‐monitoring (Mundy, 2003). This study investigated the relations among joint attention, DNMS, and self‐recognition performance in a longitudinal study of 39 normally developing toddlers from 14 to 18 months. The results indicated that development on the DNMS and self‐recognition tasks, but not a means end task, predicted joint attention at 18 months. Further analysis showed that the model was only significant for initiating joint attention (IJA). The implications of these results for the neuro‐development of IJA are discussed.     

现代国际贸易理论中的国内和国际规模收益

在二战后的国际贸易中,工业化国家之间的制造业产品的交易量巨大,这种产业内贸易现象的出现,在一定程度上对传统的赫克歇尔-俄林-萨缪尔逊贸易模型产生了冲击和质疑。经济学家从多个角度寻求对这种现象的理论解释,并开始注意产品差别化及其对规模经济的影响,但是,这些研究对贸易理论的影响很小,并且解释现实的能力也很弱。因此,把差别化的生产资料作为研究的重点,在国际收益的框架下,建立模型以推出国际规模收益,并且运用这一模型得出了国际规模收益、传统的国内规模收益和要素禀赋论之间的关系。     

Pathways between education and health: a causal modelling approach

Summary.  The association of poor education and poor health has been consistently observed in many studies and in various countries. Thus far, studies examining the mechanisms underlying this association have looked at only a limited set of potential pathways. This study simultaneously examines six distinctive pathways, which have been hypothesized to link education and health and found support from previous studies. A causal analysis of education and health was performed using structural equation models. Data were used from six phases of the National Child Development Study, which is based on following up an initial sample of 17416 children who were born in 1958. The association between education and health appears to be explained by a combination of mechanisms: adolescent health and adult health behaviours for men and women, adult social class among men and parental social class among women. We conclude that improvements in population educational attainment may not automatically lead to improvements in population health, and that health policies for improving health and reducing health inequalities need to target specific causal pathways.     

Triadic Interaction among Newly Acquainted 2-year-olds

Are children as young as 2 years old able to interact in groups of three? The study applied the family triad model first introduced by Parke, Power, and Gottman (1979 ) to the case of peer interaction. In Experiment 1 , the model was refined for use in studies of peer interaction and applied to an existing dataset of 16 triads of newly acquainted 24‐month‐olds. In Experiment 2 , the triadic coding system was further refined and applied to 12 single‐sex triads of newly acquainted 2‐year‐olds. The findings demonstrated that 2‐year‐olds are capable of triadic interaction although the predominant interaction pattern in triads is still dyadic. Contrary to past reports, triadic interaction was more likely to occur when the children were not in conflict. Both girls and boys were capable of triadic interaction.     

Joint impact of multiple observations on a subset of variables in multiple linear regression

In multiple linear regression analysis, each observation affects the fitted regression equation differently and has varying influences on the regression coefficients of the different variables. Chatterjee & Hadi (1988) have proposed some measures such as DSSE_ij (Impact on Residual Sum of Squares of simultaneously omitting the ith observation and the jth variable), F_j (Partial F-test for the jth variable) and F_j(i) (Partial F-test for the jth variable omitting the ith observation) to show the joint impact and the interrelationship that exists among a variable and an observation. In this paper we have proposed more extended form of those measures DSSE_IJ, F_J and F_J(I) to deal with the interrelationships that exist among the multiple observations and a subset of variables by monitoring the effects of the simultaneous omission of multiple variables and multiple observations.     

Happiness has traitlike and statelike properties: A reply to Veenhoven

Veenhoven (1994) contrasted hypotheses of whether happiness is a trait or state, concluding that it is a state variable. This article critiques the conceptual foundation of Veenhoven's paper, and examines technical deficiencies in his review of evidence. Based on previous findings and new analyses, we conclude that happiness has both traitlike and statelike properties, but that individual differences in happiness endure despite its situational reactivity, and explain greater variance than situational effects.     

Alternative institutional responses to asbestos

The level of asbestos risk varies widely, with insulation workers facing risks many orders of magnitude greater than other groups, such as school children. After a period of regulatory neglect, asbestos risks are now among the mos stringently regulated risks, with costs per case of cancer prevented on the order of $100 million. Asbestos litigation triggered much of the public action against asbestos, as asbestos cases constituted the majority of all product liability cases in the federal courts from 1988 to 1991. The litigation costs have, however, been substantial, almost three times as great as the amounts transferred to asbestos disease victims. Risk communication potentially could promote efficient risk levels and victim compensation.