Lessons from Drosophila models of DJ-1 deficiency

Mutations in the DJ-1 gene are associated with rare forms of autosomal recessive early-onset Parkinson's disease (PD). Although the precise physiological function of DJ-1 remains obscure, accumulating evidence suggests that DJ-1 may normally function as a redox-sensitive molecular chaperone that can protect against the deleterious effects of oxidative stress, particularly in mitochondria. Recent studies in the fruit fly, Drosophila melanogaster, have shed further light on the biological role of DJ-1. DJ-1-deficient Drosophila models exhibit distinct phenotypes but collectively highlight a prominent neuroprotective role for DJ-1 against oxidative insult. However, Drosophila lacking DJ-1 do not consistently produce a useful PD-like phenotype (that is, they generally fail to exhibit degeneration of neurons that contain the neurotransmitter dopamine), which may reflect putative compensatory neuroprotective mechanisms. DJ-1-deficient fly models further highlight the utility of Drosophila as an important tool for elucidating protein function and for modeling neurodegenerative disease.     

The relationship between two parameterizations of linear patterned mean and covariance models

Andrade and Helms (1984) study problems involving estimation and testing of linearly patterned mean and covariance matrices. They parameterize their models under the null hypothesis by using linear constraints on the alternative hypothesis parameterization. In this paper, we show that the nested models that Andrade and Helms consider can be transformed into the nested models considered by Anderson (1969, 1970, 1973) and Szatrowski (1979, 1980, 1981, 1983, 1985).     

How Parenting Style Affects False Belief Understanding

This study investigated whether mothers facilitate false belief understanding, and if so, what strategies are particularly relevant. The mothers of 64 3- and 4-year-olds were given questionnaires eliciting information about mother's education, mother's occupation, number of younger and older siblings, the time the child spends with mother, and about how mothers deal with five disciplinary situations with their child. Three variables were positively correlated with belief understanding: age, number of older siblings, and number of times mothers said they would respond to the disciplinary situations by asking the child to reflect on the victim's feelings (How Feel responses). These three variables had an independent effect on belief understanding because each was significant after accounting for the influence due to the other two variables. In contrast, there was no significant positive relation between belief understanding and mothers who engaged their child in general discussion and exploration of the disciplinary issues, or who simply reprimanded the child without discussing the situation. The effects for number of older siblings and How Feel responses remained even after the influence due to the child's age, verbal mental age, time spent with the mother, and number of younger siblings was accounted for. The results are consistent with recent research showing that parent-child relations may be important for theory of mind understanding. More importantly, they provide insight into a specific strategy by which parents may help children learn about mental states.     

A Nonparametric Test of the Predictive Regression Model

This article considers testing the significance of a regressor with a near unit root in a predictive regression model. The procedures discussed in this article are nonparametric, so one can test the significance of a regressor without specifying a functional form. The results are used to test the null hypothesis that the entire function takes the value of zero. We show that the standardized test has a normal distribution regardless of whether there is a near unit root in the regressor. This is in contrast to tests based on linear regression for this model where tests have a nonstandard limiting distribution that depends on nuisance parameters. Our results have practical implications in testing the significance of a regressor since there is no need to conduct pretests for a unit root in the regressor and the same procedure can be used if the regressor has a unit root or not. A Monte Carlo experiment explores the performance of the test for various levels of persistence of the regressors and for various linear and nonlinear alternatives. The test has superior performance against certain nonlinear alternatives. An application of the test applied to stock returns shows how the test can improve inference about predictability.     

句法角色与话题性对实体突显性的影响

句法角色与话题性都会影响语篇实体的突显性程度。采用汉语续写实验,将实验句置于语境之中,在句法角色恒定条件下操控话题性和指称形式等变量,可探察实体作为语篇话题和非话题在续写时的表征趋势,即重述形式。实验发现,在续写初期,话题性不能影响实体的重述,它与句法角色之间无交互作用|在续写后期,话题性确实对实体重述起到一定作用。此外,目标句给定指称形式虽然不影响实体重述,但在一定条件下会影响被试对重述形式的选择。     

Mothers of Children With Physical Disabilities: Influence of Family Processes on Mothers' Depressive Symptomatology

This study examines how family processes, or specific behaviors and relationships within the family, influence the risk of depression in mothers of children with disabilities. Specifically, the collective influence of children's maladaptive behavior problems, father involvement, and coparental conflict on the risk of depression among 60 married mothers of children with physical disabilities is examined. Based on data from the National Survey of Families and Households, findings showed that these mothers perceived the child's behavioral problems as less influential when they were more satisfied with the father's parenting. Furthermore, coparental conflict appeared to mediate the influence of the child's behavior and her satisfaction with the father's involvement on the mother's risk of depression.