Percolation of randomly distributed growing clusters

We investigate the problem of growing clusters, which is modeled by two dimensional disks and three dimensional droplets. In this model we place a number of seeds on random locations on a lattice with an initial occupation probability, $p$. The seeds simultaneously grow with a constant velocity to form clusters. When two or more clusters eventually touch each other they immediately stop their growth. The probability that such a system will result in a percolating cluster depends on the density of the initially distributed seeds and the dimensionality of the system. For very low initial values of $p$ we find a power law behavior for several properties that we investigate, namely for the size of the largest and second largest cluster, for the probability for a site to belong to the finally formed spanning cluster, and for the mean radius of the finally formed droplets. We report the values of the corresponding scaling exponents. Finally, we show that for very low initial concentration of seeds the final coverage takes a constant value which depends on the system dimensionality.Comment: 5 pages, 7 figure

Percolation of randomly distributed growing clusters: Finite Size Scaling and Critical Exponents

We study the percolation properties of the growing clusters model. In this model, a number of seeds placed on random locations on a lattice are allowed to grow with a constant velocity to form clusters. When two or more clusters eventually touch each other they immediately stop their growth. The model exhibits a discontinuous transition for very low values of the seed concentration $p$ and a second, non-trivial continuous phase transition for intermediate $p$ values. Here we study in detail this continuous transition that separates a phase of finite clusters from a phase characterized by the presence of a giant component. Using finite size scaling and large scale Monte Carlo simulations we determine the value of the percolation threshold where the giant component first appears, and the critical exponents that characterize the transition. We find that the transition belongs to a different universality class from the standard percolation transition.Comment: 5 two-column pages, 6 figure

Surgical Management of Calcified Hydatid Cysts of the Liver

Hydatid disease of the liver is still a major cause of morbidity in Greece. Beside the common complications of rupture and suppuration, calcification of the hepatic cysts represent a not well studied, less frequent and sometimes difficult surgical problem. In the present study 75 cases with calcified symptomatic liver echinococcosis were operated on in the 1st Propedeutic Surgical Clinic between 1964 to 1996. Twenty-eight patients were male and 47 female with ages from 23 to 78 years. The diagnosis was based mainly on the clinical picture and radiological studies. In 5 cases the operative method was cystopericystectomy. We performed evacuation of the cystic cavity and partial pericystectomy and primary closure of the residual cavity in 6 cases, omentoplasty or filling of the residual cavity with a piece of muscle of the diaphragm in 4 cases and external drainage by closed tube, in 60 cases. In 12 of those with drainage, after a period of time, a second operation with easy, removal of most of the calcareous wall plaques was performed. The mortality rate was 2%

Humor appreciation of captionless cartoons in obsessive-compulsive disorder

Background: It seems that the core neural regions and cognitive processes implicated in obsessive-compulsive disorder (OCD) pathophysiology may overlap with those involved in humor appreciation. However, to date, there have been no studies that have explored humor appreciation in OCD. The purpose of the present work was to investigate humor appreciation in a group of patients with OCD.Methods: We examined 25 patients with OCD and 25 healthy controls, matched by age, education, and gender. We administered Penn's Humor Appreciation Test (PHAT), a computerized test comprising captionless cartoons by Mordillo. Each set of stimuli consisted of two almost identical drawings, one of which was funny due to the alteration of a detail in the cartoon, whereas the other was not funny. Severity of psychopathology was evaluated with the Yale-Brown Obsessive Compulsive Scale (Y-BOCS).Results: No significant effect for group, gender or group × gender interaction was found on the PHAT scores. In OCD patients, humor appreciation was not significantly associated with age of onset, duration of illness, and obsessions, but correlated significantly with compulsions.Conclusions: Humor appreciation, based on captionless cartoons in OCD, does not seem to be deficient compared to healthy subjects but may be related to illness characteristics. © 2011 Bozikas et al; licensee BioMed Central Ltd

Functional and timing implications of transient faults in critical systems

Embedded systems in critical domains, such as auto-motive, aviation, space domains, are often required to guarantee both functional and temporal correctness. Considering transient faults, fault analysis and mitigation approaches are implemented at various levels of the system design, in order to maintain the functional correctness. However, transient faults and their mitigation methods have a timing impact, which can affect the temporal correctness of the system. In this work, we expose the functional and the timing implications of transient faults for critical systems. More precisely, we initially highlight the timing effect of transient faults occurring in the combinational and sequential logic of a processor. Furthermore, we propose a full stack vulnerability analysis that drives the design of selective hardware-based mitigation for real-time applications. Last, we study the timing impact of software-based reliability mitigation methods applied in a COTS GPU, using a fault tolerant middleware.This work has been partially funded by ANR-FASY (ANR-21-CE25-0008-01) and received funding by ESA through the 4000136514/21/NL/GLC/my co-funded PhD activity ”Mixed Software/Hardware-based Fault-tolerance Techniques for Complex COTS System-on-Chip in Radiation Environments” and the GPU4S (GPU for Space) project. Moreover, it was partially supported by the Spanish Ministry of Economy and Competitiveness under grants PID2019-107255GB-C21 and IJC2020-045931-I (Spanish State Research Agency / http://dx.doi.org/10.13039/501100011033), by the European Union’s Horizon 2020 grant agreement No 739551 (KIOS CoE) and from the Government of the Republic of Cyprus through the Cyprus Deputy Ministry of Research, Innovation and Digital Policy.Peer ReviewedPostprint (author's final draft

3D multi-agent models for protein release from PLGA spherical particles with complex inner morphologies

In order to better understand and predict the release of proteins from bioerodible micro- or nanospheres, it is important to know the influences of different initial factors on the release mechanisms. Often though it is difficult to assess what exactly is at the origin of a certain dissolution profile. We propose here a new class of fine-grained multi-agent models built to incorporate increasing complexity, permitting the exploration of the role of different parameters, especially that of the internal morphology of the spheres, in the exhibited release profile. This approach, based on Monte-Carlo (MC) and Cellular Automata (CA) techniques, has permitted the testing of various assumptions and hypotheses about several experimental systems of nanospheres encapsulating proteins. Results have confirmed that this modelling approach has increased the resolution over the complexity involved, opening promising perspectives for future developments, especially complementing in vitro experimentation

‘The International Teacher Leadership project,’ a case of international action research.

Copyright CARNThe paper arises from the International Teacher Leadership project, a research and development project involving researchers and practitioners in 14 European countries. The paper provides a conceptual exploration of the idea of teacher leadership and its role in educational reform, central to which is the idea that teachers, regardless of their level of power and organisational position, can engage in the leadership of enquiry-based development activity aimed at influencing their colleagues and embedding improved practices in their schools. The paper provides an outline of the project’s methodology which builds on that used in the Carpe Vitam Leadership for Learning project (Frost, 2008a). It is a form of collaborative action research which is highly developmental and discursive. It seeks to identify principles, strategies and tools that can be applied in a range of cultural settings. The paper includes a thematic analysis of the cultural contexts and policy environments of the participating countries in order to identify the obstacles to teacher leadership and to inform the nature of the support strategies employed