606 research outputs found
Neuroticism and responses to social comparison among cancer patients
The present study examined how the effects of three audiotapes containig different types of social comparison information on the mood of cancer patients depended on the level of neuroticism. On the procedural tape, a man and woman discussed the process of radiation therapy, on the emotion tape, they focussed on emotional reactions to their illness and treatment, while on the coping tape they focussed on the way they had been coping. A validation study among 115 students showed that the tapes were perceived as they were intended. The main study was conducted among 226 patients who were about to undergo radiation therapy. Compared to patients in the control group, as patients were higher in neuroticism, they reported less negative mood after listening to the procedural and the coping tape. Furthermore, as patients were higher in neuroticism, they reported less negative mood after listening to the coping tape than to the emotion tape. Copyright (C) 2009 John Wiley & Sons, Ltd
Airlines' Strategic Interactions and Airport Pricing in a Dynamic Bottleneck Model of Congestion
Mitigating the Cost of Anarchy in Supply Chain Systems
In a decentralized two-stage supply chain where a supplier serves a retailer who, in turn, serves end customers, operations decisions based on local incentives often lead to suboptimal system performance. Operating decisions based on local incentives may in such cases lead to a degree of system disorder or anarchy, wherein one party's decisions put the other party and/or the system at a disadvantage. While models and mechanisms for such problem classes have been considered in the literature, little work to date has considered such problems under nonstationary demands and fixed replenishment order costs. This paper models such two-stage problems as a class of Stackelberg games where the supplier announces a set of time-phased ordering costs to the retailer over a discrete time horizon of finite length, and the retailer then creates an order plan, which then serves as the supplier's demand. We provide metrics for characterizing the degree of efficiency (and anarchy) associated with a solution, and provide a set of easily understood and implemented mechanisms that can increase this efficiency and reduce the negative impacts of anarchic decisions
Density of states and magnetoconductance of disordered Au point contacts
We report the first low temperature magnetotransport measurements on
electrochemically fabricated atomic scale gold nanojunctions. As , the
junctions exhibit nonperturbatively large zero bias anomalies (ZBAs) in their
differential conductance. We consider several explanations and find that the
ZBAs are consistent with a reduced local density of states (LDOS) in the
disordered metal. We suggest that this is a result of Coulomb interactions in a
granular metal with moderate intergrain coupling. Magnetoconductance of atomic
scale junctions also differs significantly from that of less geometrically
constrained devices, and supports this explanation.Comment: 5 pages, 5 figures. Accepted to PRB as Brief Repor
Binary data corruption due to a Brownian agent
We introduce a model of binary data corruption induced by a Brownian agent
(active random walker) on a d-dimensional lattice. A continuum formulation
allows the exact calculation of several quantities related to the density of
corrupted bits \rho; for example the mean of \rho, and the density-density
correlation function. Excellent agreement is found with the results from
numerical simulations. We also calculate the probability distribution of \rho
in d=1, which is found to be log-normal, indicating that the system is governed
by extreme fluctuations.Comment: 39 pages, 10 figures, RevTe
Integrated market selection and production planning: complexity and solution approaches
Emphasis on effective demand management is becoming increasingly recognized as an important factor in operations performance. Operations models that account for supply costs and constraints as well as a supplier's ability to in°uence demand characteristics can lead to an improved match between supply and demand. This paper presents a new class of optimization models that allow a supplier to select, from a set of potential markets, those markets that provide maximum profit when production/procurement economies of scale exist in the supply process. The resulting optimization problem we study possesses an interesting structure and we show that although the general problem is NP-complete, a number of relevant and practical special cases can be solved in polynomial time. We also provide a computationally very effcient and intuitively attractive heuristic solution procedure that performs extremely well on a large number of test instances
Ecologische typologie, ontwikkelingsreeksen en waterstreefbeelden Limburg; IV: onderzoek naar aanscherping van de cenotypologie
Het project heeft tot doel te bepalen of aanscherping van de huidige cenotypologie van de Limburgse beken, ontwikkeld tijdens het project 'Ecologische typologie, ontwikkelingsreeksen en waterstreefbeelden', noodzakelijk is. Het rapport beschrijft hoe met behulp van het programma ASSOCIA en een syntaxonomische analyse is bepaald of aanscherping noodzakelijk was. Met de analyses is aangetoond dat aanscherping niet noodzakelijk was en dat de huidige onvrede met de cenotypologie kan worden opgelost tijdens het automatiseringsproces van de cenotypologie. Tot slot wordt in het rapport de ontwikkeling van een tweetal instrumenten beschreven die onontbeerlijk zijn voor het automatiseringproces: (1) een toedeelsleutel voor de referentietypologie en (2) kwaliteitsreeksen. De toedeelsleutel biedt een handvat voor de toedeling van locaties aan een referentietype. De keuze van een referentietype is noodzakelijk om de ontwikkelingsrichting van een locatie te kunnen bepalen. De kwaliteitsreeksen zijn trajecten uit het netwerk van cenotypen, met de cenotypen gerangschikt naar oplopende ecologische kwaliteit, die naar alle waarschijnlijkheid het meest zullen voorkomen in de praktijk
Beyond Blobs in Percolation Cluster Structure: The Distribution of 3-Blocks at the Percolation Threshold
The incipient infinite cluster appearing at the bond percolation threshold
can be decomposed into singly-connected ``links'' and multiply-connected
``blobs.'' Here we decompose blobs into objects known in graph theory as
3-blocks. A 3-block is a graph that cannot be separated into disconnected
subgraphs by cutting the graph at 2 or fewer vertices. Clusters, blobs, and
3-blocks are special cases of -blocks with , 2, and 3, respectively. We
study bond percolation clusters at the percolation threshold on 2-dimensional
square lattices and 3-dimensional cubic lattices and, using Monte-Carlo
simulations, determine the distribution of the sizes of the 3-blocks into which
the blobs are decomposed. We find that the 3-blocks have fractal dimension
in 2D and in 3D. These fractal dimensions are
significantly smaller than the fractal dimensions of the blobs, making possible
more efficient calculation of percolation properties. Additionally, the
closeness of the estimated values for in 2D and 3D is consistent with the
possibility that is dimension independent. Generalizing the concept of
the backbone, we introduce the concept of a ``-bone'', which is the set of
all points in a percolation system connected to disjoint terminal points
(or sets of disjoint terminal points) by disjoint paths. We argue that the
fractal dimension of a -bone is equal to the fractal dimension of
-blocks, allowing us to discuss the relation between the fractal dimension
of -blocks and recent work on path crossing probabilities.Comment: All but first 2 figs. are low resolution and are best viewed when
printe
Short-, medium-, and long-term follow-up after percutaneous transluminal coronary angioplasty for stable and unstable angina pectoris
The first 840 consecutive patients who underwent percutaneous transluminal coronary angioplasty (PTCA) performed in the same institution were retrospectively assessed at an average follow-up period of 25 months after the initial procedure. The study population consisted of 506 patients with stable angina pectoris (group 1) and 334 patients with unstable angina pectoris (group 2). Clinical end points were death, nonfatal myocardial infarction, recurrent angina pectoris necessitating bypass surgery or repeat PTCA, and event-free survival. The two groups were comparable with respect to age, sex, previous myocardial infarction, ejection fraction, and number of diseased vessels. PTCA was successful in 83.0% of group 1 and 87.1% of group 2. Follow-up rates were expressed as events per attempted PTCA in a patient group. No difference in survival was observed between the two groups, the mortality rate being approximately 2.8% at 25 months. In the group with stable angina pectoris there was a lower incidence of nonfatal myocardial infarction within the first 24 hours after angioplasty; 4.3% vs 9.0% (p less than 0.01). During long-term follow-up the increase in the incidence of nonfatal myocardial infarction was similar, resulting in an overall long-term follow-up infarction rate of 8.3% and 14.2%, respectively (p less than 0.01). A higher event-free survival was observed in group 1 within 24 hours after PTCA: 93.7% vs 84.2% (p less than 0.01). During subsequent follow-up the difference in event-free survival between the two groups was no longer significant: 68.5% vs 61.2%.(ABSTRACT TRUNCATED AT 250 WORDS
Referentiekader geldboetes
Verslag van een onderzoek naar de hoogte en wijze van berekening van geldboetes in het bestuursrecht en het strafrech
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