Controlling the Ground Reaction Force During Lifting

The control of the ground reaction force vector relative to the center of gravity (CoG) was examined while subjects performed a back-lifting task. Six male subjects (aged 24.0 +/- 2.5 years) repeatedly lifted a barbell. A biomechanical analysis that used a linked segment model revealed that the summed rotations of body segments during lifting yielded a specific rate of change of the angular momentum of the entire body. This equaled the external moment provided by Fsubg; relative to CoG. This implies that multisegment movements involve control of the angular momentum of the entire body through an appropriately directed Fsubg;. Thus, in dynamic tasks Fsubg; is pointed away from rather than lined up with the CoG, as is the case in static tasks.     

A general linear model for estimating effect size in the presence of publication bias

When the process of publication favors studies with smallp-values, and hence large effect estimates, combined estimates from many studies may be biased. This paper describes a model for estimation of effect size when there is selection based on one-tailedp-values. The model employs the method of maximum likelihood in the context of a mixed (fixed and random) effects general linear model for effect sizes. It offers a test for the presence of publication bias, and corrected estimates of the parameters of the linear model for effect magnitude. The model is illustrated using a well-known data set on the benefits of psychotherapy.Authors' note: The contributions of the authors are considered equal, and the order of authorship was chosen to be reverse-alphabetical.     

A Russian adaptation of the child behavior checklist: Psychometric properties and associations with child and maternal affective symptomatology and family functioning

The Child Behavior Checklist's (CBCL) applicability to a sample of 105 Russian 9- and 10-year-old children was evaluated by examining the internal consistency of Russian adaptations of parent and teacher report forms. In addition, child behavior scores were correlated with child reports of internalizing symptoms and maternal reports of their own internalizing symptoms and general family functioning. Finally, rates of child behavior problems and patterns of interrater agreement were compared with U.S. normative data. The psychometric properties of the adaptations demonstrate the adequacy of these instruments for use in Russia. Internal consistency and interrater agreement were generally comparable to estimates obtained in U.S. normative samples. Further, an exploration of the construct validity of the Russian versions of the CBCL and Teacher Report Form (TRF) lends additional support to the adequacy of these instruments.This work was supported in part by grants from the International Research Exchanges Board (IREX) (with funds provided by the Andrew Mellon Foundation, the National Endowment for the Humanities, and the U.S. Department of State) and the National Institute of Mental Health (MH-00508, an RSDA to D. Pauls). None of these organizations is responsible for the views expressed. In addition, the authors wish to thank Thomas Achenbach for his helpful comments and suggestions.     

On the Relation between Representational and Processing Models of Asyntactic Comprehension

Most accounts of asyntactic comprehension fall along a spectrum from pure representational accounts to pure processing accounts. The double dependency hypothesis of Mauner, Fromkin, and Cornell (1993) is an example of the former, while the SYNCHRON model of Haarman and Kolk (1991; see also Kolk, this volume) is an example of the latter. This paper attempts to demonstrate some of the ways that these two approaches interact. We introduce GENCHRON, a computer model based on Haarman and Kolk′s SYNCHRON. GENCHRON is a parser subject to the kinds of processing deficits examined in Haarman and Kolk (1991). We present a simple grammar which leads GENCHRON to produce the kinds of semantic representations which Mauner, Fromkin, and Cornell (1993) propose for asyntactic comprehenders.     

Suicide attempts in twins whose co-twins' deaths were non-suicides

Familial similarity for suicidal behavior has been interpreted by psychosocially oriented researchers as reflecting extreme grief following loss. This view would anticipate a higher frequency of attempted suicide among bereaved MZ than DZ twins (regardless of cause of death), given their generally increased social closeness. Alternatively, support for a genetic influence on suicidal behavior has been provided by findings of greater concordance among monozygotic (MZ) than dizygotic (DZ) twins, and among biological than adoptive relatives. This approach predicts that the occurrence of suicidal attempts among bereaved MZ and DZ twins whose co-twins deaths were non-suicides should not differ and should be low in frequency, given an absence of predisposing genetic factors. Attempted suicide was compared in 166 MZ and 79 DZ twins whose co-twins' deaths were non-suicides. Suicidal attempts (during the first two months following the loss) were recalled by 3 MZ twins (1.8%) and by 3 DZ twins (3.7%), a difference that was not significant. The present study, together with previous twin and adoption studies, supports the view that concordance for suicide among family members reflects a common genetic predisposition to suicidal behavior.     

Achievement motivation in relation to achievement-related recall,performance, and urine flow,a marker associated with release of vasopressin

Administration of the pituitary hormone, arginine vasopressin (AVP), enhances memory in animals and humans. Since AVP is the antidiuretic hormone, its release can be inferred from reductions in urine flow. Forty-six male adults recalled the contents of a complex story and then either were exposed to achievement arousal or were not. Significantly more of the subjects in the aroused than the nonaroused condition showed a decrease in urine flow, and the greater the decrease in urine flow among the achievement-aroused subjects, the better the recall of achievement-related story content 24 hours later. Subjects high inn Achievement, in the achievement-oriented condition, showed lower urine output at the outset of the second day and greater improvement in learning to unscramble words. Since lower urine output was also related to improvement in unscrambling words, achievement arousal may have released AVP which in turn may have facilitated achievement-related retention and performance.I am greatly indebted to Sean Connelly for assistance in carrying out this research and to Dr. Franklin Epstein of the Beth Israel Hospital, Boston, for helping me to understand how the kidney functions in producing urine.     

A possible genetic basis of accuracy in personality perception

An analysis was conducted to assess whether individuals are more accurate in perceiving those personality characteristics of other' that have a larger genetic component. Adult monozygotic (MZ) twins (63 pairs) and same-sex dizygotic (DZ) twins (35 pairs) completed the Personality Research Form-E (PRF) and the Sibling Evaluation of Personality Characteristics (SEPC) which consists of 20 sets of adjectives corresponding to the 20 trait scales of the PRF. Subjects also evaluated their co-twin with the SEPC. Self-other agreement correlations were then correlated with the heritability estimates of the PRF traits calculated on the same twin sample. The results suggest that accuracy in perceiving the co-twin's personality does increase with the heritability component of the personality dimension.     

Gender differences in coping: A further test of socialization and role constraint theories

To further test role constraint and socialization theories of gender differences in coping, two studies were conducted to examine coping strategies in individuals occupying similar roles. The relations between coping strategy frequency and effectiveness and between coping strategy use and psychological functioning also were examined. Predominantly Caucasian female and male college students participated in the studies. Results indicated support for both socialization and role constraint theories. Effectiveness and frequency of coping strategy use were moderately correlated. Gender differences in cognitive appraisal varied with dispositional vs. situational assessment. The need for a more integrated model to explain gender differences in coping and implications for existing theories are discussed.