990 research outputs found

    Stationary states of a spherical Minority Game with ergodicity breaking

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    Using generating functional and replica techniques, respectively, we study the dynamics and statics of a spherical Minority Game (MG), which in contrast with a spherical MG previously presented in J.Phys A: Math. Gen. 36 11159 (2003) displays a phase with broken ergodicity and dependence of the macroscopic stationary state on initial conditions. The model thus bears more similarity with the original MG. Still, all order parameters including the volatility can computed in the ergodic phases without making any approximations. We also study the effects of market impact correction on the phase diagram. Finally we discuss a continuous-time version of the model as well as the differences between on-line and batch update rules. Our analytical results are confirmed convincingly by comparison with numerical simulations. In an appendix we extend the analysis of the earlier spherical MG to a model with general time-step, and compare the dynamics and statics of the two spherical models.Comment: 26 pages, 8 figures; typo correcte

    Time evolution of the extremely diluted Blume-Emery-Griffiths neural network

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    The time evolution of the extremely diluted Blume-Emery-Griffiths neural network model is studied, and a detailed equilibrium phase diagram is obtained exhibiting pattern retrieval, fluctuation retrieval and self-sustained activity phases. It is shown that saddle-point solutions associated with fluctuation overlaps slow down considerably the flow of the network states towards the retrieval fixed points. A comparison of the performance with other three-state networks is also presented.Comment: 8 pages, 5 figure

    Perspectives on Systematic Analyses of Gene Function in Arabidopsis thaliana: New Tools, Topics and Trends

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    Since the sequencing of the nuclear genome of Arabidopsis thaliana ten years ago, various large-scale analyses of gene function have been performed in this model species. In particular, the availability of collections of lines harbouring random T-DNA or transposon insertions, which include mutants for almost all of the ~27,000 A. thaliana genes, has been crucial for the success of forward and reverse genetic approaches. In the foreseeable future, genome-wide phenotypic data from mutant analyses will become available for Arabidopsis, and will stimulate a flood of novel in-depth gene-function analyses. In this review, we consider the present status of resources and concepts for systematic studies of gene function in A. thaliana. Current perspectives on the utility of loss-of-function and gain-of-function mutants will be discussed in light of the genetic and functional redundancy of many A. thaliana genes

    Developments in benthos and fish in gullies in an area closed for human use in the Wadden Sea : 2002-2016

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    In the eastern Dutch Wadden Sea an area was closed for anthropogenic bottom-disturbing activities in 2005. The ‘natural’ development of the fauna in gullies located within this area was monitored and compared with the development in gullies outside the closed area. Emphasis was put on sampling the benthic fauna (every autumn). Eleven years after closure (2016) the fish population was sampled again and additional benthic samples were taken, the sea floor was mapped and the fishing pressures were calculated. Preliminary results show that throughout the investigated period the open gullies were subject to moderate shrimp fishing pressures and that the closed gullies were not fished. Closure of the gullies has not yet led to the formation of biogenic structures on the seafloor, but has led to an increase in the species richness of small benthic fauna and to subtle changes in benthic species composition. Due to the limited availability of data it was not possible to detect statistically significant differences in the fish population. Sinds november 2005 is een klein deel van de Nederlandse Waddenzee gesloten voor (potentieel) schadelijke menselijke activiteiten. Het gebied ligt ten zuiden van Rottumerplaat en Rottumeroog en beslaat zo’n 7400 hectare. Doel van de sluiting is om de ongestoorde ontwikkeling van de natuur in de Waddenzee te kunnen volgen. Dit rapport beschrijft de tussentijdse resultaten, 11 jaar naar sluiting. In het monitorprogramma is de nadruk gelegd op veranderingen in de bodemfauna die jaarlijks en vanaf 2002 in het najaar bemonsterd worden. In 2016 zijn aanvullende bemonsteringen uitgevoerd. In dat jaar is de visgemeenschap herbemonsterd, zijn additionele bodemmonsters genomen gericht op het bemonsteren van de wat grotere organismen, zijn de karakteristieken van het bodemoppervlak in kaart gebracht en is de visserijdruk in het gebied berekend. Voorlopige resultaten laten zien dat in de open geulen garnalenvisserij heeft plaatsgevonden gedurende de hier bestudeerde periode en dat in de gesloten geulen geen visserij heeft plaatsgevonden na 2005. Sluiting van de geulen heeft nog niet geleid tot vestiging van biogene structuren. Wel is de soortenrijkdom toegenomen en hebben er zich subtiele veranderingen in bodemdiersamenstelling voorgedaan. Vanwege de beperkte hoeveelheid gegevens was het niet mogelijk om uitspraken te doen over veranderingen in de vispopulatie

    Machined Versus Cast Abutments for Single Dental Implants: A 3-year within-Patient Multicentre Randomized Controlled Trial

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    PURPOSE: To compare clinical outcomes of machined titanium abutments (machined group) versus cast cobalt-chrome abutments (cast group). MATERIALS AND METHODS: Thirty-one partially edentulous subjects received two single non-adjacent implant-supported crowns each at three centres. Three and a half months after implant placement, implants were randomized at impression taking to receive one machined and one cast abutment according to a within-patient study design. Four patients dropped out and one patient lost one implant before randomization, so only 26 patients had their implants randomized. Outcome measures were: prosthesis and implant failures, any complications, and radiographic peri-implant marginal bone level changes. Patients were followed up for 3 years after loading. RESULTS: After randomization, three patients dropped out. One implant failed and two crowns on cast abutments were lost, but differences in implant and prosthesis failures were not statistically different (McNemar test P = 1.000; difference in proportions = 0.04 and P = 0.500; difference in proportions = 0.08, respectively). Two minor complications occurred in the cast group versus one in the machined group, the difference not being statistically different (McNemar test P = 1.000; difference in proportions = 0.04; 95% CI 0.18 to 22.06). Both groups presented statistically significant peri-implant marginal bone loss from implant placement to 3 years after loading, respectively -0.72 ± 0.90 mm (P = 0.001) for machined and -0.60 ± 0.61 mm (P <0.001) for cast abutments, with no statistically significant differences between the two groups (mean difference -0.12 mm; 95% CI -0.57 to 0.34; P = 0.624). Both groups gradually lost marginal peri-implant bone from loading (baseline) to 3 years after loading, but this was not statistically significant; machined lost -0.05 ± 0.12 mm while cast lost -0.14 ± 0.11 mm, a difference that was not statistically significant (mean difference 0.06 mm; 95% CI -0.24 to 0.35; P = 0.708). CONCLUSIONS: The present clinical data suggest that implant prognosis up to 3 years after loading is not affected by the choice of machined or cast abutments

    Report of the Horse Mackerel Exchange and Workshop 2006

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    Following a recommendation from PGCCDBS, a workshop on age calibration of horse mackerel was carried out. The workshop was preceded by an exchange. The objectives were: to improve the quality of horse mackerel readings by international calibration. In particular, attempt to resolve the observed differences between countries. Estimate the accuracy and precision of the age readings before and after the intercalibration. Take into account differences between areas and methods. Training of new horse mackerel readers

    Thermodynamic Fingerprints of Disorder in Flux Line Lattices and other Glassy Mesoscopic Systems

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    We examine probability distributions for thermodynamic quantities in finite-sized random systems close to criticality. Guided by available exact results, a general ansatz is proposed for replicated free energies, which leads to scaling forms for cumulants of various macroscopic observables. For the specific example of a planar flux line lattice in a two dimensional superconducting film near H_c1, we provide detailed results for the statistics of the magnetic flux density, susceptibility, heat capacity, and their cross-correlations.Comment: 4 page

    Machined Versus Cast Abutments for Dental Implants: a 1-year Within-patient Multicentre Randomized Controlled Trial Assessing Marginal Seal Capacity and Outcomes

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    PURPOSE To compare clinical outcomes of machined titanium abutments (machined group) versus cast cobalt-chrome abutments (cast group) and to evaluate in vitro their implant fit. MATERIALS AND METHODS This study comprised two parts. In the in vitro part, the im-plant–abutment fit of 5 cast abutments and 5 machined abutments screwed on with a torque of 30 Ncm was qualitatively and quantitatively evaluated using micro-computed tomography (µ-CT) and AgNO3 to reveal connection gaps. In the clinical part, 31 partially edentulous subjects received two single non-adjacent implant-supported crowns at three centres. At impression taking, three and a half months after implant placement, implants were randomized to receive a machined or cast abutment according to a wi-thin-patient study design. Unfortunately, four patients dropped out and one patient lost one implant before randomization, so only 26 patients had their implants randomized. Outcome measures were: prosthesis and implant failures, any complications, and radiographic peri-implant marginal bone level changes. Patients were followed up to 1 year after loading. RESULTS The fit of the implant–abutment connection was assessed in vitro using µ-CT scans. No gaps were revealed at any of the machined or cast abutments tested. In the clinical part, after randomization, three patients dropped out, no implant failed, but one crown on a cast abutment was replaced. The between-group difference in prosthesis failure was not statistically different (McNemar chi-square test P = 1.0; difference in proportions = 0.039). One complication occurred in each group, the difference not being statistically different (McNemar test P = 1.000; difference in proportions = 0; 95% CI 0.06 to 15.99). Both groups presented statistically significant peri-implant marginal bone loss from implant placement to 1 year after loading, respectively-0.76 ± 1.01 mm for machined and-0.69 ± 0.82 mm for cast abutments, with no statistically significant differences between the two groups (mean difference 0.07 mm; 95% CI-0.54 to 0.67; P = 0.828). Both groups gradually lost marginal peri-implant bone from loading to 1 year after loading but this was not significantly different, respectively-0.06 ± 0.56 mm for machined and-0.10 ± 0.29 mm for cast abutments, with no statistically significant differences between the two groups (P = 0.739; mean difference 0.07 mm; 95% CI-0.12 to 0.16; P = 0.739). CONCLUSIONS Our clinical data suggests that implant prognosis up to 1 year after loading is not affected by using machined or cast abutments. In support of these findings, in vitro analysis proved that both types of abutments allow a tight fit with no gaps. The-refore, for the time being dentists should feel free to choose whichever type they prefer. However, these preliminary results need to be confirmed by larger trials with at least 10 years of follow-up
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