68 research outputs found
Longtime behavior of nonlocal Cahn-Hilliard equations
Here we consider the nonlocal Cahn-Hilliard equation with constant mobility
in a bounded domain. We prove that the associated dynamical system has an
exponential attractor, provided that the potential is regular. In order to do
that a crucial step is showing the eventual boundedness of the order parameter
uniformly with respect to the initial datum. This is obtained through an
Alikakos-Moser type argument. We establish a similar result for the viscous
nonlocal Cahn-Hilliard equation with singular (e.g., logarithmic) potential. In
this case the validity of the so-called separation property is crucial. We also
discuss the convergence of a solution to a single stationary state. The
separation property in the nonviscous case is known to hold when the mobility
degenerates at the pure phases in a proper way and the potential is of
logarithmic type. Thus, the existence of an exponential attractor can be proven
in this case as well
Examining Ecological Constraints on the Intergenerational Transmission of Attachment Via Individual Participant Data Meta-analysis
Parents\u2019 attachment representations and child\u2013parent attachment have been shown to be associated, but these associations vary across populations (Verhage et al., 2016). The current study examined whether ecological factors may explain variability in the strength of intergenerational transmission of attachment, using individual participant data (IPD) meta-analysis. Analyses on 4,396 parent\u2013child dyads (58 studies, child age 11\u201396 months) revealed a combined effect size of r =.29. IPD meta-analyses revealed that effect sizes for the transmission of autonomous-secure representations to secure attachments were weaker under risk conditions and weaker in adolescent parent\u2013child dyads, whereas transmission was stronger for older children. Findings support the ecological constraints hypothesis on attachment transmission. Implications for attachment theory and the use of IPD meta-analysis are discusse
Transient anhedonia phenotype and altered circadian timing of behaviour during night-time dim light exposure in Per3(-/-) mice, but not wildtype mice.
Industrialisation greatly increased human night-time exposure to artificial light, which in animal models is a known cause of depressive phenotypes. Whilst many of these phenotypes are 'direct' effects of light on affect, an 'indirect' pathway via altered sleep-wake timing has been suggested. We have previously shown that the Period3 gene, which forms part of the biological clock, is associated with altered sleep-wake patterns in response to light. Here, we show that both wild-type and Per3(-/-) mice showed elevated levels of circulating corticosterone and increased hippocampal Bdnf expression after 3 weeks of exposure to dim light at night, but only mice deficient for the PERIOD3 protein (Per3(-/-)) exhibited a transient anhedonia-like phenotype, observed as reduced sucrose preference, in weeks 2-3 of dim light at night, whereas WT mice did not. Per3(-/-) mice also exhibited a significantly smaller delay in behavioural timing than WT mice during weeks 1, 2 and 4 of dim light at night exposure. When treated with imipramine, neither Per3(-/-) nor WT mice exhibited an anhedonia-like phenotype, and neither genotypes exhibited a delay in behavioural timing in responses to dLAN. While the association between both Per3(-/-) phenotypes remains unclear, both are alleviated by imipramine treatment during dim night-time light
Empirical Analysis of National Income and So2 Emissions in Selected European Countries
Data on GDP per capita and sulfur emissions for twelve European countries were analyzed to determine the relationship between emissions and income in these countries. As a whole, the relationship between sulfur emissions and per capita income is a fourth order polynomial and not a quadratic one as found in most studies. When countries were examined individually, seven out of the twelve countries depicted the same relationship. Looking closely at the regulations restricting sulfur emissions in the UK, the impact of all regulations supported the inverted U-shaped Kuznets curve. Individually, however, it is found that only two regulations have statistically significant impacts: Smoke Abatement Act in 1926 (reduced the amount of sulfur associated with a given level of GDP); and Clean Air Act in 1956 (increased the amount of sulfur emissions associated with a given level of GDP)
Iohexol plasma clearance measurement protocol standardization for adults: a consensus paper of the European Kidney Function Consortium.
peer reviewedInternational consensus supports the development of standardized protocols for measured glomerular filtration rate (mGFR) to facilitate the integration of mGFR testing in both clinical and research settings. To this end, the European Kidney Function Consortium convened an international group of experts with relevant experience in mGFR. The working group performed an extensive literature search to inform the development of recommendations for mGFR determination using 1-compartment plasma clearance models and iohexol as the exogenous filtration marker. Iohexol was selected as it is non-radio labeled, inexpensive, and safe, can be assayed at a central laboratory, and the other commonly used non-radio-labeled tracers have been (inulin) or are soon to be (iothalamate) discontinued. A plasma clearance model was selected over urine clearance as it requires no urine collection. A 1 compartment was preferred to 2 compartments as it requires fewer samples. The recommendations are based on published evidence complemented by expert opinion. The consensus paper covers practical advice for patients and health professionals, preparation, administration, and safety aspects of iohexol, laboratory analysis, blood sample collection and sampling times using both multiple and single-sample protocols, description of the mGFR mathematical calculations, as well as implementation strategies. Supplementary materials include patient and provider information sheets, standard operating procedures, a study protocol template, and support for mGFR calculation
Non-Parametric Identification and Estimation of Multi-Unit, Sequential, Oral, Ascending-Price Auctions With Asymmetric Bidders
Within the independent private-values paradigm, we derive the data-generating process of the winning bid for the last unit sold at multi-unit sequential English auctions when bidder valuations are draws from different distributions; i.e., in the presence of asymmetries. When the identity of the winner as well as the number of units won by each bidder in previous stages of the auction are observed, we demonstrate nonparametric identification and then propose two estimation strategies, one based on the empirical distribution function of winning bids for the last unit sold and the other based on approximation methods using orthogonal polynomials. We apply our methods to daily data from fish auctions held in Grenå, Denmark. For single-unit supply, we use our estimates to compare the revenues a seller could expect to earn were a Dutch auction employed instead
Investment in Tourism Market: A Dynamic Model of Differentiated Oligopoly
We present a theoretical model in tourism economics, assuming that the market for tourism is an oligopoly with differentiated products. Destinations (i.e., countries, regions, sites or even firms) can invest in order to improve their carrying capacity that can be interpreted as the stock of physical, natural or cultural resources. Tourism flows yield current revenues, but they are usually detrimental for the cultural or natural resource stock over time. We find the solution of the dynamic model, and in particular we find the open-loop Nash equilibrium of the game among the destinations, under alternative settings, depending on whether the arrivals are exogenous or endogenous, and depending on whether the degree of differentiation among destinations is exogenous or endogenous. The model is rather general, and it can provide answers to different specific questions, like the choice between mass- vs. elite-tourism development strategies; the effect of the number of competing products upon profits; the optimal degree of product differentiation
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