Alternating least squares algorithms for simultaneous components analysis with equal component weight matrices in two or more populations

Millsap and Meredith (1988) have developed a generalization of principal components analysis for the simultaneous analysis of a number of variables observed in several populations or on several occasions. The algorithm they provide has some disadvantages. The present paper offers two alternating least squares algorithms for their method, suitable for small and large data sets, respectively. Lower and upper bounds are given for the loss function to be minimized in the Millsap and Meredith method. These can serve to indicate whether or not a global optimum for the simultaneous components analysis problem has been attained.Financial support by the Netherlands organization for scientific research (NWO) is gratefully acknowledged.     

Effects of parental alcoholism and life stress on hispanic and non-hispanic caucasian adelescents: A prospective study

Investigated ethnicity and parental alcoholism as factors that might influence the stress vulnerability of adolescents. It extended an initial cross-sectional study of this same sample by adding two annual assessments which allowed for additional cross-sectional analyses and longitudinal tests. Hispanic and Caucasian adolescents (N=306 at Time 1) completed measures of their own life stress, family conflict, and alcohol use. Their parents reported on adolescents' internalizing and externalizing symptoms. Cross-sectional analyses at Time 2, and prospective analyses involving Time 1 and Time 2 measures were, for the most part, consistent with the original study's results. Caucasian adolescents and children of alcoholic parents appeared to be more vulnerable to stress than Hispanic adolescents and children of nonalcoholic parents. Family conflict was a partial explanation for this increased vulnerability. This research was supported by National Institute on Drug Abuse Grant DA05227 to Laurie Chassin (pricipal investigator) and Manuel Barrera, Jr. (coprincipal investigator). Susan Li was supported by an American Psychological Association Minority Fellowship Award. Portions of this research were presented at the conference, “Resiliency in Families: Racial and Ethnic Minority Families in America” that was held at the University of Wisconsin, May 31–June 2, 1994.     

Inhibition and working memory: effect of acute sleep deprivation on a random letter generation task]

The literature contains inconsistent data on the effects of acute sleep deprivation on the superior cognitive functions. The primary purpose of this study is to determine the effectiveness of inhibition, one of the functions of the working memory executive centre (EC), over an extended, 36-hour waking period. Inhibition is a cognitive mechanism whereby individuals ignore non-relevant information recorded in their working memory. We also tested the effects of a 36-hour period of acute sleep deprivation on simple reaction time. Twelve young, healthy volunteers (M = 21.5 years, sigma = 2.3) performed a random generation task involving letters and a simple reaction time psychomotor test over four sessions held at 10-hour intervals. Each participant was assigned a "constant routine." Participants were kept awake in a prone position within a room whose environment was held strictly constant (light, noise, temperature, meals, etc.). This control procedure provided assurance that any variation in participant performance was solely caused by sleep deprivation. The random generation task, nearly two minutes in length, consisted in verbally producing a sequence of 100 letters in a random fashion (i.e. by inhibiting, for example, alphabetical order) and by keeping to a set rhythm. Our assumption was that capacity for inhibition diminished as the number of hours of sleep deprivation increased. The simple reaction test, 10 minutes in length, involved pressing a button as swiftly as possible to cause a black square to disappear from a screen. In this case our assumption was that acute sleep deprivation alters simple reaction time. Analysis of variance (ANOVA) through repeated measures using the "sessions" factor as an intra-subject variable showed no significant changes in randomization indices of the random generation task, contrary to analysis of average simple reaction times. Participants' reaction times deteriorated over the first two minutes of the test during the night they were deprived of sleep. It would seem that the contradictory results of previous studies of the effects of acute sleep deprivation on the inhibition function would be due to errors in factor identification. In conclusion, the inhibition function, as measured during the performance of a brief task, seems to remain intact during an extended, 36-hour waking period. Simple reaction time assessed by means of a brief psychomotor test is affected during a night of sleep deprivation. The working-memory inhibition executive function shows greater resistance to acute sleep deprivation than does psychomotor reaction time for the performance of short tasks.     

Sequential effects in the lexical decision task: The role of the item frequency of the previous trial

Two lexical decision experiments were conducted to determine whether there is a specific, localized influence of the item frequency of consecutive trials (i.e., first-order sequential effects) when the trials are not related to each other. Both low-frequency words and nonwords were influenced by the frequency of the precursor word (Experiment 1). In contrast, high-frequency words showed little sensitivity to the frequency of the precursor word (Experiment 2), although they showed longer reaction times for word trials preceded by a nonword trial. The presence of sequential effects in the lexical decision task suggests that participants shift their response criteria on a trial-by-trial basis.     

Differential effects of forward or simultaneous conditioned stimulus-unconditioned stimulus intervals on the defensive behavior system of the Norway rat (Rattus norvegicus)

To test several predictions derived from a behavior-systems approach, the authors assessed Pavlovian fear conditioning in rats after 30 trials of forward, simultaneous, or unpaired training. Direct evidence of conditioned fear was collected through observation of flight and freezing reactions during presentations of the conditioned stimulus (CS) alone. The authors also tested the CS's potential to reinforce an instrumental escape response in an escape-from-fear paradigm. On the one hand, rats that received forward training showed conditioned freezing, but no conditioned flight was observed. On the other hand, rats that received simultaneous training showed conditioned flight, but no conditioned freezing was observed. Rats that received either forward or simultaneous pairings showed instrumental learning of the escape-from-fear response. Implications for several theories of Pavlovian conditioning are discussed.     

MMPI-2 and MCMI-III scores among dutch inpatient substance abusers: Assessing correspondence and cross-cultural equivalence

The Millon Clinical Multiaxial Inventory (MCMI-II and MCMI-III) and the Minnesota Multiphasic Personality Inventory (MMPI-2) were applied to 263 Dutch inpatient substance abusers with multiple psychiatric diagnoses, and the results compared with those of 306 North-American substance abusers studied by Ward (1995). We looked for structural similarity both across groups (per instrument) and across the two instruments (per sample), using principal components analysis and congruence analysis. The component structure found by Ward was partly replicated in the Dutch group, thus cross-validating the use of the two instruments with these patients. Moreover, as found by Ward, the MMPI-2 content and supplementary scales of the Dutch sample proved to be important determinants of the first three MMPI-2 components, adding to convergent validity. Questions remained about the influence of the (dis)continuity of MCMI-II and MCMI-III on the replicability of the MCMI components.     

Educating Engineers for the Public Good Through International Internships: Evidence from a Case Study at Universitat Politècnica de València

Science and Engineering Ethics - At Universitat Politècnica de València, Meridies, an internship programme that places engineering students in countries of Latin America, is one of the...     

Effects of Level of Processing on Implicit and Explicit Memory in Depressed Mood

Recently, several studies have addressed the question of whether depression affects priming in implicit memory tasks. The main aim of this experiment was to assess the presence of a bias for negative information in explicit memory (free recall) and implicit memory (word-stem completion) tasks among subclinically depressed subjects compared to nondepressed subjects, using the typical levels of processing manipulation. The results of this study show the existence of a mood-congruent memory bias for both implicit and explicit memory in depressed subjects. The theoretical implications of these findings for implicit and explicit memory biases associated with depressed mood are discussed.     

Medical expertise asa function of task difficulty

This paper is concerned with factors that disrupt the pattern of forward reasoning characteristic of experts with accurate performance. Two experiments are described. In the first, the performances of cardiologists, psychiatrists, and surgeons in diagnostic explanation of a clinical problem in cardiology were examined. In the second, the performances of cardiologists and endocrinologists in diagnostic explanation of clinical problems within and outside their domains of expertise were examined. The performances of researchers and practicing physicians are also compared. The results of Experiment 1 replicated earlier results regarding the relationship between forward reasoning and accurate diagnosis. There were no differences in recall as a function of expertise. Experts did not show any bias toward using specific knowledge from their own areas of expertise. The results of Experiment 2 showed that the breakdown of forward reasoning was related to the structure of the task. In particular, nonsalient cues induced some backward reasoning even in subjects with accurate diagnoses. Some differences were also found between the types of explanation used by researchers and practitioners. The practitioners referred more to clinical components in their explanations, whereas the researchers focused more on the biomedical components.     

Relation of parental support and control to adolescents' externalizing symptomatology and substance use: A longitudinal examination of curvilinear effects

Past research has generated inconsistent findings regarding the relation of parental control and support to adolescent problem behaviors. Using two waves of data collected 1 year apart, the current study examined the influence of parental control and support on adolescents' externalizing symptoms, alcohol use, and illicit substance use. A sample of adolescents and their parents (@#@ N =454) was studied, within which approximately half of the adolescents were at high risk because of parental alcoholism. Multipleregression analyses of crosssectional data showed a negative quadratic relation between parental control and adolescent externalizing symptomatology, and between parental control and adolescent illicit substance use. Parental control had a negative linear relation to adolescent alcohol use. Parental support showed a negative quadratic relation to adolescent illicit substance use, and negative linear relations to adolescent alcohol use and externalizing symptoms. Although longitudinally adjusted contemporaneous results were consistent with crosssectional findings, parental support and control were prospectively related only to adolescent alcohol use. The quadratic relations suggest that adolescents who receive either extreme of parental support or control are at risk for problem behaviors.