Showing papers by "Tilburg University published in 1987"
TL;DR: In this paper, it was hypothesized that both the final cardiac deceleration and the late wave of the Contingent Negative Variation at the end of the foreperiod of a simple reaction time task are composed of a movement-related component and a stimulus-anticipation component.
Abstract: Based on previous research, it was hypothesized that both the final cardiac deceleration and the late wave of the Contingent Negative Variation (CNV) at the end of the foreperiod of a simple reaction time task are composed of a movement-related component and a stimulus-anticipation component. Forty right-handed adult female and male subjects performed a time estimation task. They had to press a button with the index-finger at intervals of 20 to 22 seconds. After the button-press a visual stimulus was presented, which provided Knowledge of Results (KR) about the correctness of the timing. For half the subjects the delay between button-press and stimulus presentation was 2 s, for the other half it was 4 s. Recordings of both the electrocardiogram (ECG) and the electroencephalogram (EEG) were obtained, the latter being derived bilaterally from precentral. postcentral. and parietal sites. As was expected, cardiac deceleration was found both prior to the movement and prior to stimulus presentation in both delays. At the cortical level the movement was preceded by a Readiness Potential (RP). Stimulus presentation was preceded by a cortical negative wave, the Stimulus-Preceding Negativity (SPN), at all positions. Precentrally and postcentrally the Stimulus-Preceding Negativity exhibited a larger right hemisphere preponderance in the 2-s delay than in the 4-s delay.
154 citations
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TL;DR: The major theme of as mentioned in this paper is that the commercial banks have weathered the debt crisis, while many debtor countries remain in economic paralysis or worse, and that consensus is reflected in at least two ways: in the discounts observed in the secondary market prices for LDC debt, and in discounts in the stock market pricing of banks with exposure in the LDCs.
Abstract: The major theme of this paper is that the commercial banks have weathered the debt crisis, while many debtor countries remain in economic paralysis or worse. There is a growing consensus that much of the LDC debt will not be fully serviced in the future, and that consensus is reflected in at least two ways: in the discounts observed in the secondary market prices for LDC debt, and in the discounts in the stock market pricing of banks with exposure in the LDCs.
148 citations
TL;DR: This paper argued that any main effect or interaction term in such a design can reflect bias and that difficulties in the interpretation of observed cross-cultural differences in data can be avoided only if the researcher succeeds in introducing external variables in terms of which the variance in the factor culture can be reduced to zero.
Abstract: Contrary to the tradition in cross-cultural psychology in which bias is identified with the stimulus by culture interaction in an analysis of variance design, it is argued (and illustrated) here that any main effect or interaction term in such a design can reflect bias. It is suggested that difficulties in the interpretation of observed cross-cultural differences in data can be avoided only if the researcher succeeds in introducing external variables in terms of which the variance in the factor culture can be reduced to zero. This implies, somewhat paradoxically, that in a satisfactory cross-cultural study there is no variance left to be explained in terms of culture.
115 citations
TL;DR: In this paper, a simplicial variable dimension algorithm developed by van der Laan and Talman for proper labels of S is extended to the case of general labellings, and a distinctive feature of the new algorithm is that lower dimensional simplicial movement can occur both on the boundary and in the interior of S.
Abstract: This paper deals with the nonlinear complementarity problem on the product space of unit simplices, S. A simplicial variable dimension algorithm developed by van der Laan and Talman for proper labellings of S is extended to the case of general labellings. General labellings allow a more natural description of the complementarity problem on the boundary of S. A distinctive feature of the new algorithm is that lower dimensional simplicial movement can occur both on the boundary and in the interior of S. In contrast, the van der Laan and Talman algorithm for proper labellings of S allows lower dimensional simplicial movement only in the interior of S. Computational experiments confirm the usefulness of general labellings for solving nonlinear complementarity problems.
98 citations
TL;DR: The study of stress in relation to the onset, course, and outcomes of disease is considered, and models describing the relationship between stress and the course of disease or medical outcome are presented and discussed.
53 citations
TL;DR: In this article, several measures of nonnormality of matrices are discussed, i.e., functions v: Cn, n → R plus where v(A)=0 iff A is normal.
47 citations
TL;DR: Regular contacts between fellow patients decreased negative feelings (depression, anxiety and psychological complaints) and increased self-esteem and this was true especially for patient under treatment and those, whose illness had recurred.
44 citations
TL;DR: In this article, a micro-econometric limited dependent variable model is presented to simultaneously explain the decision whether to go on vacation or not, the choice of destination and the decision on the level of the vacation expenditures.
Abstract: We present a micro-econometric limited dependent variable model, which simultaneously explains the decision whether to go on vacation or not, the choice of destination and the decision on the level of the vacation expenditures. The model has been estimated on the basis of a cross-section of Dutch households; we find a striking difference in income elasticity between domestic vacations and vacations abroad, and a large impact of owning certain durables (such as a boat) on the choice of destination. To illustrate the potential of the model, some simulations are performed.
43 citations
TL;DR: In this paper, a methodological comparison of factor analysis and regression on the basis of their results is presented, and the authors point out various small errors and misunderstandings, and present a methodological analysis of the two fields.
Abstract: 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.
41 citations
TL;DR: Nurkse as mentioned in this paper argued that the attraction of advanced consumption standards exerts itself fairly widely, though of course unevenly, among the poorer two-thirds of mankind, and as a result he was predisposed to a particular description of its consequences.
41 citations
TL;DR: In this paper, the authors describe a price adjustment mechanism which leads to an economic equilibrium, starting from an arbitrarily chosen initial price vector, which is a global and universal price adjustment process.
TL;DR: In this paper, the implications of different information patterns for firms in oligopolistic resource markets are considered, and it is shown that an increase in information can be detrimental to firms in the industry.
TL;DR: In this paper, data on Dutch-Turkish language-mixing behavior of Turkish children growing up in The Netherlands are presented and analyzed, and it was found that the functional characteristics of the children's languagemixing are compatible with earlier results.
Abstract: Data on Dutch-Turkish language-mixing behavior of Turkish children growing up in The Netherlands are presented and analysed. The purpose of this study was to determine the extent to which the descriptive models developed in research on language-mixing are generalizable. It was found that the functional characteristics of the children's language-mixing are compatible with earlier results. Structural analysis of the data, however, yielded results that shed considerable doubt on the universal applicability of surface structure constraint rules for sentence-internal language-mixing.
TL;DR: In this article, a simplicial variable dimension restart algorithm is introduced to solve the nonlinear complementarity problem on the product space S of unit simplices, which is similar to the octahedral algorithm on Rn having 2n rays.
Abstract: A new simplicial variable dimension restart algorithm is introduced to solve the nonlinear complementarity problem on the product spaceS of unit simplices. The triangulation which underlies the algorithm differs from the triangulations ofS used thus far. Moreover, the number of rays along which the algorithm can leave the arbitrarily chosen starting point is much larger. More precisely, there is a ray leading from the starting point to each vertex ofS. In caseS is the product ofn one-dimensional unit simplices the alogrithm is similar to the octahedral algorithm onRn having 2n rays. Also, the accuracy of an approximate solution in the terminal simplex of the algorithm is in general better than for the other algorithms onS. Computational results will show that the number of iterations for the new algorithm is much less. The examples concern the computation of equilibria in noncooperative games, exchange economies and trade models.
TL;DR: In this paper, the use of the technique of latent variables to gain insight into the consequences of shift work in health care is discussed, and the results show that shift work is less harmful than in industry, the health of the nurses being only slightly affected by it.
Abstract: This paper discusses the use of the technique of latent variables to gain insight into the consequences of shift work in health care. The method used differs from methods most often used in research concerning shift work, and the results show that shift work in health care seems to be less harmful than in industry, the health of the nurses being only slightly affected by it. However, in the context of nurses' social life, the results are more in accordance with what has been found in other inquiries; shift work is found to have a rather strong negative effect.
TL;DR: Stepwise multiple regression showed that cognitions and coping determined a considerable part of the variance in the dependent variables: well-being, hospital admissions, and absence from work due to asthma.
Abstract: This study investigates the meaning of cognitions and coping in well-being, hospital admissions, medication consumption, and absence from work due to asthma in asthmatic patients. Patients completed five questionnaires: the Respiratory Illness Opinion Survey (Kinsman, Jones, Matus, & Schum, 1976), measuring external control, psychological stigma, and optimism; the Asthma Coping Questionnaire (Maes, Schlosser, & Vromans, 1986), measuring coping mechanisms; the Dutch version of the STAI (van der Ploeg, Defares, & Spielberger, 1979), measuring state and trait anxiety; the Questionnaire for Inner Well-Being (Hermans & Tak-van de Ven, 1973), measuring well-being; and the General Questionnaire for Asthmatic Patients (Maes et al., 1986) measuring medical outcome. Stepwise multiple regression showed that cognitions and coping determined a considerable part of the variance in the dependent variables: well-being, hospital admissions, and absence from work due to asthma.
TL;DR: In this article, the relationship between fractionated reaction time components and response force was studied in a simple reaction time task, where subjects squeezed a force transducer between the right thumb and index finger.
TL;DR: In this article, a variable dimension simplicial restart algorithm is introduced to compute economic equilibria, which has one ray to each of the 2n+1ź2 faces of then-dimensional price simplex, whereas the existing algorithms haven+1 rays either to each facet or to each vertex of the unit simplex.
Abstract: A new variable dimension simplicial restart algorithm is introduced to compute economic equilibria. The number of rays along which the algorithm can leave the starting point differs from the thusfar known algorithms. More precisely, the new algorithm has one ray to each of the 2n+1ź2 faces of then-dimensional price simplex, whereas the existing algorithms haven+1 rays either to each facet or to each vertex of the unit simplex. The path of points followed by the algorithm can be interpreted as a globally and universally convergent price adjustment process. The process is also economically meaningful and therefore it is a good alternative for the well-known Walras' tatonnement process. Computational results show that the algorithm is competitive with the most efficient simplicial algorithms developed thusfar.
TL;DR: It was found that the decrease of performance due to sleep deprivation was larger when stimuli were degraded, and KR counteracted the effect of sleep deprivation; however, KR improved performance irrespective of signal quality.
TL;DR: In this paper, the effect of the General Old Age Pensions Act on the distribution of lifetime income in the Netherlands has been investigated by means of a simple simulation model, and the authors have shown that the vertical income redistribution within a generation is limited by differences in mortality rates and differences in the duration of working life between income groups.
TL;DR: In this article, a continuous deformation algorithm is introduced on S × [1, ∞, where S denotes the product space of unit simplices, with arbitrary grid refinement between two subsequent levels.
Abstract: A continuous deformation algorithm is introduced on S × [1, ∞, where S denotes the product space of unit simplices, with arbitrary grid refinement between two subsequent levels. The set S × [1, ∞ is triangulated in such a way that for each m, m = 1, 2,..., S × {m} is triangulated by the so-called V-triangulation. The algorithm starts by applying a variable dimension algorithm on S until an approximating simplex has been found on level 1. Then the algorithm follows a path of approximating simplices in S × [1, ∞, starting on level 1, until a certain level or a certain accuracy of a solution of the underlying problem has been reached. If the algorithm returns to level 1, then we again apply the variable dimension algorithm until a new approximating simplex is found on level 1, etc. We allow solutions to lie on the boundary of S × [1, ∞ in which case the algorithm, in general, will follow a path on the boundary of S × [1, ∞.
TL;DR: This article went into both sociolinguistic and psycholinguistic aspects of literacy education to immigrant children, focusing on the literacy needs of ethnic minority groups in a multilingual community, the language policies that authorities can follow with regard to literacy and the monolingual and bilingual literacy instruction models that these policies can give rise to.
Abstract: This article goes into both sociolinguistic and psycholinguistic aspects of literacy education to immigrant children. From a sociolinguistic point of view attention is given to the literacy needs of ethnic minority groups in a multilingual community, the language policies that authorities can follow with regard to literacy and the monolingual and bilingual literacy instruction models that these policies can give rise to. From a psycholinguistic point of view aspects of immigrant children's processes of learning to read are highlighted, and arguments for bilingual literacy instruction are summed up. In addition, a perspective of literacy education to immigrant children is given.
TL;DR: It is proved that any totally dual integral description of a full-dimensional polyhedron is locally strongly unimodular in every vertex.
Abstract: We prove that any totally dual integral description of a full-dimensional polyhedron is locally strongly unimodular in every vertex.
01 Jan 1987
TL;DR: In this paper, the authors look at teachers' knowledge and understanding of classrooms in terms of interpretation of nonverbal and situational cues using two sets of videotapes of classroom episodes, one in Hebrew and one in Dutch, which were viewed by teachers in cross-cultural settings.
Abstract: This article looks at teachers' knowledge and understanding of classrooms in terms of interpretation of nonverbal and situational cues Two sets of videotapes of classroom episodes were prepared, one in Hebrew and one in Dutch, which were viewed by teachers in cross-cultural settings Teachers responded in writing and in group discussions regarding the perceived nature of the viewed episodes and then commented on the interpretation cues Analysis of written responses and protocols of discussions yielded insights into the two cultures CLASSROOM SITUATIONS, INTERPRETATION BY TEACHERS, NONVERBAL CUES, CROSS-CULTURAL
TL;DR: The ideas of a simplicial variable dimension restart algorithm to approximate zero points onRn and of a linear complementarity problem pivoting algorithm are combined to an algorithm for solving the nonlinear complementarityproblem with lower and upper bounds.
Abstract: Ideas of a simplicial variable dimension restart algorithm to approximate zero points onRn developed by the authors and of a linear complementarity problem pivoting algorithm are combined to an algorithm for solving the nonlinear complementarity problem with lower and upper bounds. The algorithm can be considered as a modification of the2n-ray zero point finding algorithm onRn. It appears that for the new algorithm the number of linear programming pivot steps is typically less than for the2n-ray algorithm applied to an equivalent zero point problem. This is caused by the fact that the algorithm utilizes the complementarity conditions on the variables.
01 Jan 1987
TL;DR: The relationship between individual and institutional activities on the one hand and the environment on the other can be analyzed on different spatial levels and for different time spans as discussed by the authors, and studies range from the scale of "vertical villages" in high-rise buildings (Wekerle, 1976) to "urban villages" (Gans, 1962), to "global village" (McLuhan, 1968), and from observations on the use of urban parks and playgrounds measuring time in minutes (Gold, 1972; Hole, 1966) to historical research seeking to uncover developments during the course
Abstract: One of the underlying purposes of community planning is the creation of settings that support the activities of households and institutions. In this context, spatial planning aims at the realization and maintenance of a state of congruence between human behavior and the physical environment. The relationships between individual and institutional activities on the one hand and the environment on the other can be analyzed on different spatial levels and for different time spans. Studies range from the scale of “vertical villages” in high-rise buildings (Wekerle, 1976) to “urban villages” (Gans, 1962), to “global villages” (McLuhan, 1968), and from observations on the use of urban parks and playgrounds measuring time in minutes (Gold, 1972; Hole, 1966) to historical research seeking to uncover developments during the course of centuries (Hohenberg & Lees, 1985).
01 Apr 1987
TL;DR: The paper describes the adaptations in the chart parser which was implemented as part of the TENDUMdialogue system and shows that tree-like constituent structures with discontinuities can be given a precise definition which makes them just as acceptable for syntactic representation as ordinary trees.
Abstract: This paper discusses the consequences of allowing discontinuous constituents in syntactic representions and phrase-structure rules, and the resulting complications for a standard parser of phrase-structure grammar.It is argued, first, that discontinuous constituents seem inevitable in a phrase-structure grammar which is acceptable from a semantic point of view. It is shown that tree-like constituent structures with discontinuities can be given a precise definition which makes them just as acceptable for syntactic representation as ordinary trees. However, the formulation of phrase-structure rules that generate such structures entails quite intricate problems. The notions of linear precedence and adjacency are reexamined, and the concept of "n-place adjacency sequence" is introduced. Finally, the resulting form of phrase-structure grammar, called "Discontinuous Phrase-Structure Grammar", is shown to be parsable by an algorithm for context-free parsing with relatively minor adaptations. The paper describes the adaptations in the chart parser which was implemented as part of the TENDUMdialogue system.
TL;DR: In this article, the authors found that the warning stimulus has a facilitatory effect on the early ipsilateral component and an inhibitory effect on late bilateral component of the blink reflex, while preparation for a response is seen in both R1 and R2 magnitudes.
Abstract: In a warned reaction time task blink reflexes were evoked electrically at different points in time during a 3-s foreperiod between the warning signal (WS) and the response signal (RS;. Two groups of 16 well-trained right-handed subjects participated. One group was informed by the warning signal as to whether or not a voluntary blink response was to be given following the response signal. For the other group of subjects, response-relevant information was delivered by the response signal. Reaction times were shorter when subjects were precued by the warning signal, which indicates a more efficient preparation in this condition. In the blink reflex an early ipsilateral component (R1) and a late bilateral component (R2) could be distinguished. Within 300 ms after the warning signal, an increase in R1 was seen which was more pronounced when the warning signal precued the required response. R2 was inhibited shortly after the warning signal. At the end of the foreperiod R1 increased more and R2 was more inhibited the higher the response certainty. The general conclusion is that the presentation of a warning stimulus has a facilitatory effect on R1 and an inhibitory effect on R2. A warning stimulus with more information results in an extra increase in R1 magnitude only, while preparation for a response is seen in both R1 and R2 magnitudes.