111,468 research outputs found
Habituation to pain : a motivational-ethological perspective
Habituation to pain is mainly studied using external pain stimuli in healthy volunteers, often to identify the
underlying brain mechanisms, or to investigate problems in habituation in specific forms of pain (eg, migraine). Although these studies provide insight, they do not address one pertinent question: Why do we habituate to pain? Pain is a warning signal that urges us to react. Habituation to pain may thus be dysfunctional: It could make us unresponsive in situations where sensitivity and swift response to bodily damage are essential. Early theories of habituation were well aware of this argument. Sokolov argued that responding to pain should not decrease, but rather increase with repeated exposure, a phenomenon he called “sensitization.” His position makes intuitive sense: Why would individuals respond less to pain that inherently signals bodily harm? In this topical review, we address this question from a motivational ethological perspective. First, we describe some core characteristics of habituation. Second, we discuss theories that explain how and when habituation occurs. Third, we introduce a motivational-ethological perspective on habituation and explain why habituation occurs. Finally, we discuss how a focus on habituation to
pain introduces important methodological, theoretical, and clinical implications, otherwise overlooked
Group membership and staff turnover affect outcomes in group CBT for persistent pain
The effects of two contextual factors, group membership and staff turnover, on the outcome of group cognitive behavioral therapy (CBT) for persistent pain were investigated. The data came from end of treatment and one month follow-up assessments of 3050 individuals who attended an intensive group programme over sixteen years. Intraclass correlations (ICC) showed significant intragroup effects on self-efficacy (ICC = 0.16 at end of treatment; 0.12 at one month), catastrophizing (ICC = 0.06; 0.13) and distance walked (ICC = 0.20; 0.19). This underlines the importance of modelling group membership when analyzing data from group interventions. Linear regression showed that high periods of staff turnover were significantly related to poorer outcomes on self-efficacy and distance walked at end of treatment, with the effect on self-efficacy persisting to one month follow-up. Having demonstrated significant contextual effects in an existing data set, further research is needed to explore the mechanisms by which these effects operate
Exchangeability and sets of desirable gambles
Sets of desirable gambles constitute a quite general type of uncertainty
model with an interesting geometrical interpretation. We give a general
discussion of such models and their rationality criteria. We study
exchangeability assessments for them, and prove counterparts of de Finetti's
finite and infinite representation theorems. We show that the finite
representation in terms of count vectors has a very nice geometrical
interpretation, and that the representation in terms of frequency vectors is
tied up with multivariate Bernstein (basis) polynomials. We also lay bare the
relationships between the representations of updated exchangeable models, and
discuss conservative inference (natural extension) under exchangeability and
the extension of exchangeable sequences.Comment: 40 page
Accept & Reject Statement-Based Uncertainty Models
We develop a framework for modelling and reasoning with uncertainty based on
accept and reject statements about gambles. It generalises the frameworks found
in the literature based on statements of acceptability, desirability, or
favourability and clarifies their relative position. Next to the
statement-based formulation, we also provide a translation in terms of
preference relations, discuss---as a bridge to existing frameworks---a number
of simplified variants, and show the relationship with prevision-based
uncertainty models. We furthermore provide an application to modelling symmetry
judgements.Comment: 35 pages, 17 figure
The utility of a digital simulation language for ecological modeling
Dynamic modeling of ecological phenomena has been greatly facilitated by the recent development of continuous system simulator programs. This paper illustrates the application of one of these programs, S/360 Continuous System Modeling Program (S/360 CSMP), to four systems of graduated complexity. The first is a two species system, with one feeding on the other, using differential equations with constant coefficients. The second and third systems involve two competing plant species in which the coefficients of the differential equations are varying with time. The final example considers the management of a postulated buffalo herd in which the dynamics of the herd population and composition by sex and age is combined with various strategies to control its size and to optimize buffalo production
Paramagnetic resonance effect in viscoelastic materials Annual progress report, 1 Jan. - 31 Dec. 1968
Electron paramagnetic resonance investigation of fracture in viscoelastic material
Crosslinked agarose encapsulated sorbents resistant to steam sterilization. Preparation and mechanical properties
The application of agarose in hemoperfusion is hampered by the lack of a suitable sterilization method. A technique has been developed for the crosslinking of agarose encapsulated sorbents by the reaction with 1,3-dichloro-2-propanol (DCP) under strong alkaline conditions. A twofold molar excess of DCP with respect to agarose and an equimolar amount of sodium hydroxide at a concentration of 0.3 mol/L with a reaction time of 1-4 h at 50°C are found to be the optimal conditions. The compressive strength of crosslinked beads is increased by a factor of 4. Agarose capsules are found to degrade by the influence of Y radiation, but are resistant to steam sterilization at 134°C during at least 30 min when crosslinked
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