Publications by authors named "Koops W"

From Bill Kessen's idea of the child as a "cultural invention" (Kessen, 1983) it follows that developmental psychology cannot function fruitfully without historical analysis. Developmentalists should stop "positivistic dreaming" and develop a historical developmental psychology. The history of childhood shows how a historical process of infantilization has taken place since Rousseau and the 19th century pedagogical and educational theories and institutions.

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Viscosity plays an important role in dispersion of spilled surface oil, so does adding chemical dispersants. For seven different oil grades, entrainment rate and initial droplet size distribution were investigated using a plunging jet apparatus with coupled camera equipment and subsequent image analysis. We found that amount of oil entrained is proportional to layer thickness and largely independent of oil properties: A dispersant dose of 1:200 did not result in a significantly different entrainment rate compared to no dispersants.

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The aim of this study was to examine the variation in antibiotic use and the effects of external factors on trends in antibiotic use at the herd level by using the number of daily dosages as an indicator for antibiotic use. For this purpose, antibiotic use was analyzed in 94 dairy herds in the Netherlands from 2005 to 2012. The herds were divided into 3 groups of farmers: one group was guided in their antibiotic use from 2008 to 2010 as part of the project, whereas the other 2 groups were not actively guided.

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Application of chemical dispersants or mechanical dispersion on surface oil is a trade-off between surface effects (impact of floating oil) and sub-surface effects (impact of suspended oil). Making an informed decision regarding such response, requires insight in the induced change in fate and transport of the oil. We aim to identify how natural, chemical and mechanical dispersion could be quantified in oil spill models.

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This study quantifies the effect of oil layer thickness on entrainment and dispersion of oil into seawater, using a plunging jet with a camera system. In contrast to what is generally assumed, we revealed that for the low viscosity "surrogate MC252 oil" we used, entrainment rate is directly proportional to layer thickness. Furthermore, the volume of stably suspended small oil droplets increases with energy input (plunge height) and is mostly proportional to layer thickness.

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The milk production of a dairy cow is characterized by lactation production, which is calculated from daily milk yields (DMY) during lactation. The DMY is calculated from one or more milkings a day collected at the farm. Various milking systems are in use today, resulting in one or many recorded milk yields a day, from which different calculations are used to determine DMY.

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Background: Medical students in clerkship are continuously confronted with real and relevant patient problems. To support clinical problem solving skills, students perform a Critical Appraisal of a Topic (CAT) task, often resulting in a paper. Because such a paper may contain errors, students could profit from discussion with peers, leading to paper revision.

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Article Synopsis
  • Oil spills from tanker accidents and platforms can severely harm marine environments, affecting ecosystems, fishing industries, and tourism.
  • The impact of an oil spill depends on factors like spill size, oil type, weather conditions, and location near sensitive areas.
  • While removing visible oil is a common response, the use of chemicals for dispersal can have negative side effects, so evaluating the situation carefully is crucial.
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Background: Medical workplace learning consists largely of individual activities, since workplace settings do not lend themselves readily to group learning. An electronic Learning Management with System Computer-Supported Collaborative Learning (CSCL) could enable learners at different workplace locations to discuss personal clinical experiences at a distance to enhance learning.

Aim: To explore whether CSCL-enabled structured asynchronous discussions on an authentic task has additional value for learning in the medical workplace.

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Accurate tumor excision is crucial in the locoregional treatment of cancer, and for this purpose, surgeons often rely on guide wires or radioactive markers for guidance toward the lesion. Further improvement may be obtained by adding optical guidance to currently used methods, in the form of intra-operative fluorescence imaging. To achieve such a multimodal approach, we have generated markers that can be used in a pre-, intra-, and post-operative setting, based on a cocktail of a dual-emissive inorganic dye, lipids, and pertechnetate.

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Liposarcomas are separated into clinicopathological entities with a characteristic morphological spectrum and mutually exclusive genetic alterations. Therefore, the rare occurrence of cases with combined patterns of well-differentiated liposarcoma and myxoid liposarcoma designated as mixed-type liposarcoma pose a conceptual problem. Moreover, this feature may have consequences for treatment choice and prognosis.

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High burnout levels have been observed in medical residents. The purpose of this study is to assess the burnout rates and potential determinants of burnout in a sample of medical residents. In total, 58 medical residents working in a Dutch teaching hospital, received questionnaires at home, including the Maslach Burnout Inventory (MBI).

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The spectrum of lipomatous lesions ranges from benign to highly malignant disease. Differentiation between these lesions is important to indicate prognosis and choose the most appropriate treatment. Hemosiderotic fibrohistiocytic lipomatous lesion (HFLL) is a rare subtype of lipomatous tumor.

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The present meta-analytic review aimed to clarify divergent findings concerning the relation between reactive and proactive aggression in children and adolescents. Fifty-one studies with 17,965 participants were included in the analysis. A significant correlation between reactive and proactive aggression was found.

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Aim: A survival benefit has been observed for colorectal cancer patients with peritoneal carcinomatosis treated by cytoreductive surgery with intraoperative hyperthermic intraperitoneal chemotherapy (HIPEC). However, this treatment modality is associated with a considerable morbidity and mortality and in a significant number of patients survival is not improved. We studied whether poor survivors could be identified on preoperative computed tomography (CT), in order to avoid unnecessary surgery.

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We studied emotional aspects of social information processing (SIP) and their specific relations with reactive and proactive aggression in 54 boys ages 7 to 13 who had been referred for aggressive behavior problems and a comparison group. Participants listened to vignettes concerning provocations by peers and answered questions concerning SIP, own and peer's emotions, and emotion regulation. Aggressive boys attributed more hostile intent, happiness, and less guilt; reported more anger; mentioned less adaptive emotion-regulation strategies; generated more aggressive responses; and evaluated aggressive responses less negatively than comparison boys.

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Background And Objectives: In patients with colorectal cancer, it is important to diagnose peritoneal carcinomatosis as well as to detect location and size of peritoneal tumor dissemination in view of treatment planning. The aim of this study was to investigate the detection accuracy of computed tomography (CT).

Methods: Preoperative CT-scans from 25 consecutive patients with peritoneal carcinomatosis from colorectal or appendiceal origin were independently blindly reviewed by 2 radiologists.

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Breast cancers in gene mutation carriers may escape mammographic detection because of rapid growth and tumor expansion. Therefore, they may mimic benign lesions on the mammogram. Twenty-nine BRCA 1/2 mutation carriers under surveillance developed 31 breast cancers between 1994 and 2001 at a mean age of 44.

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Objectives of this study are to describe the biological basis for multiphasic milk production and to propose a new empirical model for the lactation curve. To illustrate this model, we used data on 3573 first-lactation Holsteins having lactations of various lengths (285, 345, 405, 465, and 525 d) and with various days open (45, 105, 165, 225, and 285 d). The model describes an increasing first phase of milk yield and a series of decreasing phases of yield.

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Proper assessment of factors contributing to failure of an egg to hatch, i.e., infertility and embryonic mortality, is important in poultry production.

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Tested the hypothesis that aggressive boys' tendency to attribute hostile intentions to peers is exacerbated in a negative emotional state. Twenty-nine highly aggressive boys in special education, 12 moderately aggressive boys in regular education, and 16 nonaggressive boys in regular education inferred peers' intentions in 8 vignettes concerning ambiguous provocation by peers. Mild negative emotions were induced by unjust loss of a manipulated computer game.

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Tested the hypothesis that aggressive boys' tendency to attribute hostile intentions to peers is exacerbated in a negative emotional state. Twenty-nine highly aggressive boys in special education, 12 moderately aggressive boys in regular education, and 16 nonaggressive boys in regular education inferred peers' intentions in 8 vignettes concerning ambiguous provocation by peers. Mild negative emotions were induced by unjust loss of a manipulated computer game.

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A meta-analytic review was conducted to explain divergent findings on the relation between children's aggressive behavior and hostile attribution of intent to peers. Forty-one studies with 6,017 participants were included in the analysis. Ten studies concerned representative samples from the general population, 24 studies compared nonaggressive to extremely aggressive nonreferred samples, and 7 studies compared nonreferred samples with children referred for aggressive behavior problems.

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Breakout analysis of 11,254 chicken eggs that failed to hatch was used to assess the influence of storage days on the distribution for time of embryonic mortality during incubation and on reproductive efficiency. Eggs were collected over 30 d, stored from 2 through 18 d, and incubated in two hatches. For each storage day within hatch, proportions of embryonic mortality during each of the 21 d of incubation, among embryos that did not survive incubation, were fitted by a diphasic Weibull distribution.

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Our primary objective was to improve on an existing model for the individual weekly egg production curve by modeling the curve as a sum of logistic functions: one for the increasing phase of production and a sum for the decreasing phases. To illustrate the model, we used four data sets from two pairs of individuals. For these data, the model consisted of an increasing phase and a single decreasing phase of production: y(t) = m k1((1 - e(-t))/(1 + e(-t))) - m(k1 - k2)((1 - e(-t))/(1 + e(-(t-c2)))) where y(t) is egg production at week t, m is maximum production during a specific time interval, k1 is proportion of maximum production for the increasing phase, k2 is proportion of maximum production for the decreasing phase, and c2 is point of inflection from the upper level of the increasing phase to the lower level of the decreasing phase; thus, c2 is a measure of persistency of egg production.

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