26,008 research outputs found
POPCORN: a Supervisory Control Simulation for Workload and Performance Research
A multi-task simulation of a semi-automatic supervisory control system was developed to provide an environment in which training, operator strategy development, failure detection and resolution, levels of automation, and operator workload can be investigated. The goal was to develop a well-defined, but realistically complex, task that would lend itself to model-based analysis. The name of the task (POPCORN) reflects the visual display that depicts different task elements milling around waiting to be released and pop out to be performed. The operator's task was to complete each of 100 task elements that ere represented by different symbols, by selecting a target task and entering the desired a command. The simulated automatic system then completed the selected function automatically. Highly significant differences in performance, strategy, and rated workload were found as a function of all experimental manipulations (except reward/penalty)
Zeehondenjacht in Nederland:1591-1962
Eeuwenlang is in Nederland op zeehonden gejaagd. Vanaf 1591 betaalde men zelfs een premie voor iedere gedode zeehond die men kon laten zien. Een premiestelsel zou met enkele onderbrekingen tot in 1942 blijven bestaan. In 1962 werd de zeehondenjacht in Nederland beëindigd. Deze studie behandelt die jacht over een periode van 370 jaar, vanaf het begin in 1591 tot de beëindiging. Het is een wandeling door de tijd, een rechtshistorische studie met
veel raakvlakken met andere disciplines. Een wandeling langs veranderende staatsinrichting, oorlogen, technische en wetenschappelijke ontwikkelingen, die alle hun weerslag op de zeehondenjacht hebben gehad.Faber, S. [Promotor
The monopole mass in the three-dimensional Georgi-Glashow model
We study the three-dimensional Georgi-Glashow model to demonstrate how
magnetic monopoles can be studied fully non-perturbatively in lattice Monte
Carlo simulations, without any assumptions about the smoothness of the field
configurations. We examine the apparent contradiction between the conjectured
analytic connection of the `broken' and `symmetric' phases, and the
interpretation of the mass (i.e., the free energy) of the fully quantised 't
Hooft-Polyakov monopole as an order parameter to distinguish the phases. We use
Monte Carlo simulations to measure the monopole free energy and its first
derivative with respect to the scalar mass. On small volumes we compare this to
semi-classical predictions for the monopole. On large volumes we show that the
free energy is screened to zero, signalling the formation of a confining
monopole condensate. This screening does not allow the monopole mass to be
interpreted as an order parameter, resolving the paradox.Comment: 12 pages, 7 figures, uses revtex. Minor changes made to the text to
match with the published version at
http://link.aps.org/abstract/PRD/v65/e12500
Study protocol: Delayed intervention randomised controlled trial within the Medical Research Council (MRC) Framework to assess the effectiveness of a new palliative care service
Background: Palliative care has been proposed to help meet the needs of patients who suffer
progressive non-cancer conditions but there have been few evaluations of service development
initiatives. We report here a novel protocol for the evaluation of a new palliative care service in
this context.
Methods/Design: Using the MRC Framework for the Evaluation of Complex Interventions we
modelled a new palliative care and neurology service for patients severely affected by Multiple
Sclerosis (MS). We conducted qualitative interviews with patients, families and staff, plus a
literature review to model and pilot the service. Then we designed a delayed intervention
randomised controlled trial to test its effectiveness as part of phase II of the MRC framework.
Inclusion criteria for the trial were patients identified by referring clinicians as having unresolved
symptoms or psychological concerns. Referrers were advised to use a score of greater than 8 on
the Expanded Disability Scale was a benchmark. Consenting patients newly referred to the new
service were randomised to either receive the palliative care service immediately (fast-track) or
after a 12-week wait (standard best practice). Face to face interviews were conducted at baseline
(before intervention), and at 4â6, 10â12 (before intervention for the standard-practice group), 16â
18 and 22â24 weeks with patients and their carers using standard questionnaires to assess
symptoms, palliative care outcomes, function, service use and open comments. Ethics committee
approval was granted separately for the qualitative phase and then for the trial.
Discussion: We publish the protocol trial here, to allow methods to be reviewed in advance of
publication of the results. The MRC Framework for the Evaluation of Complex Interventions was
helpful in both the design of the service, methods for evaluation in convincing staff and the ethics
committee to accept the trial. The research will provide valuable information on the effects of
palliative care among non-cancer patients and a method to evaluate palliative care in this context
Massive pulmonary embolism presenting as disseminated intravascular coagulation.
Disseminated intravascular coagulation (DIC) can be defined as evidence of activation of the coagulation mechanism resulting in proteolysis of fibrinogen by thrombin and plasmin and an acute thrombocytopenia. The association of pulmonary embolism (PE) with DIC has recently been reported but in reviewing recent textbooks of hematology, there is no mention of PE as a cause of DIC. Clinicians need to be made aware of this association since it affects the patient who is thought to be autoanticoagulated as well as the patient who has DIC of unknown cause. PE needs to be included in the differential diagnosis of an autoanticoagulated state and in DIC of unknown etiology. In both instances the recommended treatment is full-dose intravenous heparin therapy
Electronic Raman scattering in Magnetite, Spin vs. Charge gap
We report Raman scattering data of single crystals of magnetite (Fe3O4) with
Verwey transition temperatures (Tv) of 123 and 117K, respectively. Both single
crystals reveal broad electronic background extending up to 900 wavenumbers
(~110 meV). Redistribution of this background is observed when samples are
cooled below Tv. In particular, spectra of the low temperature phase show
diminished background below 300 wavenumbers followed by an enhancement of the
electronic background between 300 and 400 wavenumbers. To enhance the effect of
this background redistribution we divide the spectra just below the transition
by the spectra just above the transition. A resultant broad peak-like feature
is observed, centered at 370 wavenumbers (45 meV). The peak position of this
feature does not scale with the transition temperature. We discuss two
alternative assignments of this feature to a spin or charge gap in magnetite.Comment: 4 figures, 1 tabl
Prediction of Intake of Hay Differing in Species and Maturity by Goats
Eight species of forage, a cool-season perennial (Festuca arundinacea) and annual grass (Triticum aestivum), four warm-season perennial grasses (Bothriochloa caucasica, B. ischaemum, Cynodon dactylon, and Tripsacum dactyloides), a warm season annual (Digitaria sanguinalis) and a perennial legume (Medicago sativa), were cut at two or three maturities to provide a wide array of quality difference (n=20). Twenty wether goats (Capra hicus) were fed the hays in four different trials using an incomplete block so that each hay was fed to four different goats. Alfalfa produced the highest DM, but lowest neutral detergent fiber (NDF) intake. Intake was best predicted with eating time, passage rate and lag time, and hay CP and ADF (R2 =0.57). Digestibility was best predicted with percentage acid detergent fiber (ADF), permanganate lignin (PML) and CP, and ruminating time (R2 =0.35). Weight gain (g/d) could be predicted with digestible dry matter intake (r2 =0.42; P \u3c 0.001). Regression curves were different (P \u3c 0.05) among forage types
Weerbaar tegen water? Crisismanagement bij overstromingen
Kerstmis 1993. In Limburg hebben vele bewoners van dorpen en steden die aan de Maas liggen natte in plaats van witte voeten. De Maas is buiten zijn oevers getreden na heftige en aanhoudende regenval in heel West-Europa. Ook in Frankrijk, België en Duitsland is sprake van overstromingen. Enkele duizenden Limburgers moeten hun huizen verlaten. De schade aan woningen, bedrijven en infrastructurele voorzieningen is aanzienlijk. De Koningin en leden van hun kabinet komen de getroffenen een hart onder de riem steken. De betreffende delen van Limburg worden officieel tot rampgebied verklaard. Een nationale televisieactie levert veel geld op, maar de totale schade bedraagt meer dan 150 miljoen gulde
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