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171.
In a previous paper, we reviewed the literature on family assessment and set out some principles that can be derived from previous work. This paper describes the development of a system for family assessment which uses these principles and then gives a brief account of the practical difficulties encountered in applying such a system. (Empirical data on the system will be presented in subsequent papers as they become available.)  相似文献   
172.
Visual-motor control loop: a linear system?   总被引:2,自引:0,他引:2  
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173.
Twelve subjects performed a high signal rate vigilance task, once after a night's sleep, and once after a night without sleep. Raw scores were transformed into the signal detection parameters, d' and β. After sleep deprivation, detection performance was significantly impaired. This was reflected in a fall of d', whereas β was not significantly altered. Analysing the control data alone for comparison with other vigilance studies revealed a decrement in % signals detected and d', and an increase in β from the first to the second half of the test.  相似文献   
174.
175.
Psychometric properties and determinants of Buckner's Neighborhood Cohesion Index (NCI) have previously been reported for 206 individuals from three Washington, DC suburbs. This study analyses the properties and determinants of the scale for 1182 mine workers in Elliot Lake, a remote Canadian single-industry town. Data were collected through in-person interviews. The scale in the Elliot Lake sample was highly reliable (α=.91) and the Elliot Lake and Washington NCI item-total scale correlations were similar. Multiple regression found income and education related significantly negatively and years in neighborhood and home ownership significantly positively to NCI with coefficients comparable to those Buckner found in Washington. However, additional significant positive predictors of NCI were home equity, length of home ownership, and the presence of both pre-school-age and school-age children in the home, whereas a significant negative predictor was poor health. The NCI thus appears to be stable across societies, and shows systematic relationships with background variables. Home equity, duration of home ownership, children and health were significant predictors of NCI in our larger Canadian sample. This paper is based on data from the Elliot Lake Tracking Study. We are eager to acknowledge the contribution of our collaborators, David Leadbeater and Peter Suschnigg, in designing the study and collecting the data. We take full responsibility for our conclusions. Funding for the study has been provided by the Laurentian University Institute for Northern Ontario Research and Development, The Ontario Ministry of Northern Development and Mines, and the Elliot Lake Job Creation Fund.  相似文献   
176.
Sixteen subjects performed a test of visual watch-keeping twice, at the same hour of the same day of successive weeks. The test lasted 40 min. On one of these occasions the test was done after normal sleep the previous night; signals were detected at a steady rate throughout. On the other occasion the subjects had no sleep the previous night; they passed the time in innocuous leisure activities. Here a similar level of performance was maintained for the first 20 min. of the test. After this the rate of signal detection declined steadily. In the final quarter of the test the rate was roughly one third that of the first quarter.

Signals missed were divided into three categories, (u) signals missed while watching the display, (b) signals missed while not watching, and, (c) signals missed while asleep. Lack of sleep produced increases in all three of these categories.

These results support previous suggestions that a test has to be prolonged before performance is affected by moderate loss of sleep; they also suggest that it is the simpler, or perhaps the more predictable, tests which are more affected.  相似文献   
177.
We report a test of an influential theory of employee turnover: the unfolding model ( Lee & Mitchell, 1994 ; Lee, Mitchell, Holtom, McDaniel, & Hill, 1999 ). We describe and critique this classificatory model, and propose both theory‐based and empirical refinements. The two extant tests of the current version of the model have both been with accountants in the United States, so the generalisability of the model is as yet unproven. We present results of an attempt to classify 352 nurse leavers from the United Kingdom's National Health Service using the unfolding model. In contrast to the findings of Lee et al. (1999 ), the model failed to classify a substantial number of nurse leavers, and specific hypotheses derived from the model received only partial support. Classification failures were investigated using both quantitative and qualitative data. Leavers were more likely to be classified if they had no dependants and described their quit as avoidable. Although the unfolding model incorporates more kinds of turnover than traditional turnover models, such systematic classification failure casts doubt on claims that it offers a comprehensive account of turnover. We explain failures with reference to: (i) shortcomings in a key measure; (ii) the characteristics of the occupational group studied; and (iii) the extremely tight labor market for this group of leavers. Nous testons la théorie influente concernant le turnover des salariés: the unfolding model ( Lee & Mitchell, 1994 ; Lee, Mitchell, Holtom, McDaniel & Hill, 1999 ). Après avoir décrit et critiqué ce modèle de classification, nous proposons des améliorations tant au niveau théorique qu’empirique. La version actuelle du modèle a été testée à deux reprises auprès de comptables des Etats‐Unis, aussi ce modèle n’a pas pu être généralisé. Nous présentons les résultats obtenus en utilisant le “unfolding model” auprès de 352 infirmières du service de santé national du Royaume‐Uni qui sont sur le départ. Contrairement aux résultats obtenus par Lee et al. (1999 ), le modèle n’a pas permis de classer un nombre substantiel d’infirmières sur le départ et certaines hypothèses découlant de ce modèle ne reçoivent qu’une validation partielle. Ces échecs de classification ont été analysés tant quantitativement que qualitativement. Il ressort que les sujets étaient plus facilement classés si ils n’avaient aucune personne à charge et si ils décrivaient leur départ comme évitable. Bien que le “unfolding model” incorpore plus de formes de turnover que les modèles traditionnels, un échec de classification aussi systématique questionne quant à sa revendication à offrir une approche complète du turnover. Nous expliquons ces échecs par: (i) des imperfections dans la mesure principale (ii) les caractéristiques du groupe de salariés étudiés (iii) un marché du travail extrêmement difficile pour ce groupe de personnes sur le départ.  相似文献   
178.
This study identified levels of distress, and predictors of levels of distress, in women undergoing assessment for genetic risk of breast/ovarian cancer based on their family history. It comprised a cohort study following 154 women who completed questionnaires at entry into a cancer genetic assessment programme and following risk provision. Independent significant associates of anxiety following risk provision were age, neuroticism, feeling hopeless about developing cancer, a perceived lack of control over developing cancer, lack of a social confidant, and a coping response involving acceptance/resignation. Depression was associated with age, neuroticism, feeling hopeless about developing cancer, lack of social confidant, and a coping response involving acceptance/resignation. To avoid high levels of psychological morbidity in future cohorts undergoing cancer genetic risk assessment, information should be given that emphasises that some degree of control over health outcomes through behaviour change or increased surveillance is possible.  相似文献   
179.
Research reported here concerns neural processes relating to stimulus equivalence class formation. In Experiment 1, two types of word pairs were presented successively to normally capable adults. In one type, the words had related usage in English (e.g., uncle, aunt). In the other, the two words were not typically related in their usage (e.g., wrist, corn). For pairs of both types, event‐related cortical potentials were recorded during and immediately after the presentation of the second word. The obtained waveforms differentiated these two types of pairs. For the unrelated pairs, the waveforms were significantly more negative about 400 ms after the second word was presented, thus replicating the “N400” phenomenon of the cognitive neuroscience literature. In addition, there was a strong positive‐tending wave form difference post‐stimulus presentation (peaked at about 500 ms) that also differentiated the unrelated from related stimulus pairs. In Experiment 2, the procedures were extended to study arbitrary stimulus—stimulus relations established via matching‐to‐sample training. Participants were experimentally näive adults. Sample stimuli (Set A) were trigrams, and comparison stimuli (Sets B, C, D, E, and F) were nonrepresentative forms. Behavioral tests evaluated potentially emergent equivalence relations (i.e., BD, DF, CE, etc.). All participants exhibited classes consistent with the arbitrary matching training. They were also exposed also to an event‐related potential procedure like that used in Experiment 1. Some received the ERP procedure before equivalence tests and some after. Only those participants who received ERP procedures after equivalence tests exhibited robust N400 differentiation initially. The positivity observed in Experiment 1 was absent for all participants. These results support speculations that equivalence tests may provide contextual support for the formation of equivalence classes including those that emerge gradually during testing.  相似文献   
180.
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