Explicit candecomp/parafac solutions for a contrived 2 × 2 × 2 array of rank three

Kruskal, Harshman and Lundy have contrived a special 2 × 2 × 2 array to examine formal properties of degenerate Candecomp/Parafac solutions. It is shown that for this array the Candecomp/Parafac loss has an infimum of 1. In addition, the array will be used to challenge the tradition of fitting Indscal and related models by means of the Candecomp/Parafac process.     

The rank of reduced dispersion matrices

Psychometricians working in factor analysis and econometricians working in regression with measurement error in all variables are both interested in the rank of dispersion matrices under variation of the diagonal elements. Psychometricians concentrate on cases in which low rank can be attained, preferably rank one, the Spearman case. Econometricians cocentrate on cases in which the rank cannot be reduced below the number of variables minus one, the Frisch case. In this paper we give an extensive historial discussion of both fields, we prove the two key results in a more satisfactory and uniform way, we point out various small errors and misunderstandings, and we present a methodological comparison of factor analysis and regression on the basis of our results.Financial support by the Netherlands Organization for the Advancement of Pure Research (ZWO) is gratefully acknowledged.     

Some additional results on principal components analysis of three-mode data by means of alternating least squares algorithms

Kroonenberg and de Leeuw (1980) have developed an alternating least-squares method TUCKALS-3 as a solution for Tucker's three-way principal components model. The present paper offers some additional features of their method. Starting from a reanalysis of Tucker's problem in terms of a rank-constrained regression problem, it is shown that the fitted sum of squares in TUCKALS-3 can be partitioned according to elements of each mode of the three-way data matrix. An upper bound to the total fitted sum of squares is derived. Finally, a special case of TUCKALS-3 is related to the Carroll/Harshman CANDECOMP/PARAFAC model.     

A simplification of a completeness proof of Guaspari and Solovay

The modal completeness proofs of Guaspari and Solovay (1979) for their systems R and R ^– are improved and the relationship between R and R ^– is clarified.     

Mechanical output about the ankle in countermovement jumps and jumps with extended knee

In this study the mechanical output (e.g., force, contraction velocity, instantaneous power) about the ankle was measured during a jump with and without occurrence of transportation of power and pre-stretch potentiation. To examine this, a model of the m. triceps surae was used. Eleven subjects performed a maximal one-legged countermovement jump (CMJ) and a maximal one-legged jump with extended knee (EKJ). Ground reaction forces, cinematographic data and electromyograms of m. triceps surae were recorded. The power output, defined as the product of moment and angular velocity, and work done about the ankle were higher during CMJ (1404 W, 130 J) than during EKJ (852 W, 76 J). The peak moments were the same during both jumps. The model of the m. triceps surae showed that the power delivered by m. triceps surae was higher during CMJ than during EKJ, as a result of catapult-action of m. gastrocnemius tendon. The difference in work done is explained, in addition to transportation of energy, by a greater contraction range of m. soleus during CMJ. There is no reason to assume that pre-stretch potentiation plays a role in the difference in mechanical output. The results show that the mechanical output of muscles in complex movements is strongly dependent on the dynamics of the movement, and not only on its contractile capacity.     

A controlled trial of cognitive-behavioural and behavioural treatment of anorexia nervosa

This study was undertaken to investigate whether a cognitive-behavioural treatment procedure was superior to a standard behavioural treatment, in the outpatient therapy of patients with anorexia nervosa. The two treatments were also compared with a control treatment procedure consisting of routine outpatient management. Each group consisted of eight subjects. All the groups showed some improvement, but the findings did not provide support for the prediction that cognitive-behavioural treatment, designed specifically to manipulate both attitudes and behaviour, was superior to the other types of treatment. The implications of the findings are considered.     

The Importance of Contraceptive Attributes Among College Students

This study assessed how ratings of the importance of contraceptive attributes varied with gender, age, relationship status, and contraceptive method usually used. In a classroom setting, 210 male and 217 female university students completed the 55-item Contraceptive Attribute Questionnaire (CAQ). Significant differences on importance ratings were found between women and men, age groups, women using barrier methods and women using the pill, and by relationship status. The underlying dimensions of the CAQ were investigated through factor analysis, and somewhat different factors emerged for men and women. Implications for the provision of family planning services to college students are discussed.     

Job Evaluation and Gender: The Case of University Faculty

This study examined the effects of students' and professors' sex on student evaluations of professors' teaching effectiveness. Ratings of over four hundred faculty made by over nine thousand students were analyzed. After controlling for a large number of variables, the main results showed that (a) male faculty were given significantly higher evaluations on global teacher effectiveness and academic competence than female faculty; (b) when controlling for extraneous variables, female faculty were not found to be rated as more sensitive to student needs than male faculty; and (c) when making overall, global judgments of faculty performance, students seem to place more weight on academic competence for male faculty than for female faculty.     

A multidimensional assessment of parent-identified behavior problem toddlers

Sixty-eight 2-and 3-year-olds (46 parent-referred, 22 controls) participating in an identification, assessment, and follow-up study of hyperactivity and related behavior problems were evaluated on parent-report, observational, and cognitive measures. Referred youngsters were described by both parents as more active, inattentive, difficult to discipline, and aggressive with peers than were controls. Mothers of referred children also reported a more difficult infancy period. Laboratory assessments confirmed parental reports of current problems. Referred children shifted activities more during free play, were more active and inattentive during structured tasks, and made more impulsive responses on a delay task than did controls. Discriminant function analysis indicated that parental ratings of activity paired with laboratory measures of sustained attention and impulsivity correctly classified 88% of the sample. These data suggest that the core symptoms of hyperactivity can be identified in very young children, although their prognostic significance remains to be determined.This research was supported by Grant No. R01 MH 32735 from the National Institute of Mental Health to the first author. Thanks are due to the parents and children who participated so enthusiastically in this study. The dedication of Patricia Cluss is gratefully acknowledged. Mady Fingeret, Frank McKee, Jenny Palermo, Susan Riley, Elizabeth Schaughency, Sheree Thomas, and Russell Walters are also thanked for their help in data collection.