Runtime Distributions and Criteria for Restarts

Randomized algorithms sometimes employ a restart strategy. After a certain number of steps, the current computation is aborted and restarted with a new, independent random seed. In some cases, this results in an improved overall expected runtime. This work introduces properties of the underlying runtime distribution which determine whether restarts are advantageous. The most commonly used probability distributions admit the use of a scale and a location parameter. Location parameters shift the density function to the right, while scale parameters affect the spread of the distribution. It is shown that for all distributions scale parameters do not influence the usefulness of restarts and that location parameters only have a limited influence. This result simplifies the analysis of the usefulness of restarts. The most important runtime probability distributions are the log-normal, the Weibull, and the Pareto distribution. In this work, these distributions are analyzed for the usefulness of restarts. Secondly, a condition for the optimal restart time (if it exists) is provided. The log-normal, the Weibull, and the generalized Pareto distribution are analyzed in this respect. Moreover, it is shown that the optimal restart time is also not influenced by scale parameters and that the influence of location parameters is only linear

CT-Guided Percutaneous Embolization of a Rasmussen Aneurysm with Ethylene Vinyl Alcohol Copolymer

info:eu-repo/semantics/publishedVersio

TVL₁ Planarity Regularization for 3D Shape Approximation

The modern emergence of automation in many industries has given impetus to extensive research into mobile robotics. Novel perception technologies now enable cars to drive autonomously, tractors to till a field automatically and underwater robots to construct pipelines. An essential requirement to facilitate both perception and autonomous navigation is the analysis of the 3D environment using sensors like laser scanners or stereo cameras. 3D sensors generate a very large number of 3D data points when sampling object shapes within an environment, but crucially do not provide any intrinsic information about the environment which the robots operate within. This work focuses on the fundamental task of 3D shape reconstruction and modelling from 3D point clouds. The novelty lies in the representation of surfaces by algebraic functions having limited support, which enables the extraction of smooth consistent implicit shapes from noisy samples with a heterogeneous density. The minimization of total variation of second differential degree makes it possible to enforce planar surfaces which often occur in man-made environments. Applying the new technique means that less accurate, low-cost 3D sensors can be employed without sacrificing the 3D shape reconstruction accuracy

Portal Vein Embolization With N-Butyl-Cyanoacrylate Through an Ipsilateral Approach Before Major Hepatectomy: Single Center Analysis of 50 Consecutive Patients

PURPOSE: To evaluate the efficacy of portal vein embolization (PVE) with n-Butyl-cyanoacrylate (NBCA) through an ipsilateral approach before major hepatectomy. Secondary end-points were PVE safety, liver resection and patient outcome. METHODS: Over a 5-year period 50 non-cirrhotic consecutive patients were included with primary or secondary liver cancer treatable by hepatectomy with a liver remnant (FLR) volume less than 25% or less than 40% in diseased livers. RESULTS: There were 37 men and 13 women with a mean age of 57 years. Colorectal liver metastases were the most frequent tumor and patients were previously exposed to chemotherapy. FLR increased from 422 ml to 629 ml (P < 0.001) after PVE, corresponding to anincrease of 52%. The FLR ratio increased from 29.6% to 42.3% (P < 0.001). Kinetic growth rate was 2.98%/week. A negative association was observed between increase in the FLR and FLR ratio and FLR volume before PVE (P = 0.002). In 31 patients hepatectomy was accomplished and only one patient presented with liver insufficiency within 30 days after surgery. CONCLUSIONS: PVE with NBCA through an ipsilateral puncture is effective before major hepatectomy. Meticulous attention is needed especially near the end of the embolization procedure to avoid complications.info:eu-repo/semantics/publishedVersio

O significado da vacina contra rubéola para as mulheres grávidas

Se trató de describir el significado de la vacuna contra la rubeola para las mujeres que se enteraron del embarazo después de recibir la vacuna dupla viral, debido a la campaña contra la rubeola-2001, en la DIR XX de São João da Boa Vista. Fue adoptada como referencia la Teoría de la Representaciones Sociales. La colección de datos fue realizada a través de la técnica de Discurso del Sujeto Colectivo con 18 gestantes y mujeres embarazadas hasta 30 días después de la aplicación de la vacuna, consideradas suceptibles a la rubeola, habitantes de 10 municipios de la región. Considerando los discursos de las mujeres, fue posible detectar los diferentes resultados de la vacuna contra la rubeola cuando es aplicada durante la gestación, representada como amenaza a su integridad, a la de su hijo y a su relación conyugal. Esos significados se constituyen en importante fuente de información que brinda a los profesionales de la salud y gestores una reflexión sobre desempeño de su papel como agentes promotores de la salud.Buscou-se descrever o significado da vacina contra rubéola para mulheres que se descobriram grávidas após receberem a vacina dupla viral, por ocasião da campanha contra rubéola-2001, na DIR XX de São João da Boa Vista, SP. Adotou-se como referencial a Teoria das Representações Sociais. A coleta de dados foi realizada através da técnica do Discurso do Sujeito Coletivo com 18 mulheres grávidas e que engravidaram até 30 dias após aplicação da vacina, consideradas suscetíveis à rubéola, residentes em 10 municípios da região. Através dos discursos das mesmas, foi possível desvelar a diversidade de significados da vacina contra a rubéola quando aplicada durante a gravidez, representada como ameaça à sua integridade, à de seu filho e ao seu relacionamento conjugal. Esses significados constituem-se em importante fonte de informação que propicia aos profissionais de saúde e gestores reflexão sobre o seu papel como agentes promotores de saúde.The research was aimed at describing the meaning of the rubella vaccine to women who were discovered pregnant after having received the measles-rubella vaccine during the 2001 campaign against rubella, and who lived in 10 cities within the region of DIR XX from São João da Boa Vista. The theory of Social Representation was used as a reference framework for the research, and data were collected through the Collective Subject Discourse technique, involving 18 women who either were pregnant or became pregnant within 30 days after having received the vaccine. Through their discourse, it was possible to unveil the diversity of meanings the rubella vaccine has when dispensed during pregnancy, characterized as a threat to their and their children's physical integrity and to their conjugal relationship. The meanings constitute an important source of information that allows health professionals and administrators to reflect, so they can reconsider their role as health promoters

Simonsenia aveniformis sp nov (Bacillariophyceae), molecular phylogeny and systematics of the genus, and a new type of canal raphe system

The genus Simonsenia is reviewed and S. aveniformis described as new for science by light and electron microscopy. The new species originated from estuarine environments in southern Iberia (Atlantic coast) and was isolated into culture. In LM, Simonsenia resembles Nitzschia, with bridges (fibulae) beneath the raphe, which is marginal. It is only electron microscope (EM) examination that reveals the true structure of the raphe system, which consists of a raphe canal raised on a keel (wing), supported by rib like braces (fenestral bars) and tube-like portulae; between the portulae the keel is perforated by open windows (fenestrae). Based on the presence of portulae and a fenestrated keel, Simonsenia has been proposed to be intermediate between Bacillariaceae and Surirellaceae. However, an rbcL phylogeny revealed that Simonsenia belongs firmly in the Bacillariaceae, with which it shares a similar chloroplast arrangement, rather than in the Surirellaceae. Lack of homology between the surirelloid and simonsenioid keels is reflected in subtle differences in the morphology and ontogeny of the portulae and fenestrae. The diversity of Simonsenia has probably been underestimated, particularly in the marine environment.Polish National Science Centre in Cracow within the Maestro program [N 2012/04/A/ST10/00544]; Sciences and Technologies Foundation-FCT (Portugal) [SFRH/BD/62405/2009]info:eu-repo/semantics/publishedVersio

Fuzzy modelling of acid mine drainage environments using geochemical, ecological and mineralogical indicators

Fuzzy logic was applied to model acid mine drainage (AMD) and to obtain a classification index of the environmental impact in a contaminated riverine system. The data set used to develop this fuzzy model (a fuzzy classifier) concerns an abandoned mine in Northern Portugal— Valdarcas mining site. Here, distinctive drainage environments (spatial patterns) can be observed based on the AMD formed in the sulphide-rich waste-dumps. Such environments were established, as the effluent flows through the mining area, using several kinds of indicators. These are physical–chemical, ecological and mineralogical parameters, being expressed in a quantitative or qualitative basis. The fuzzy classifier proposed in this paper is a min– max fuzzy inference system, representing the spatial behaviour of those indicators, using the AMD environments as patterns. As they represent different levels (classes) of contamination, the fuzzy classifier can be used as a tool, allowing a more reasonable approach, compared with classical models, to characterize the environmental impact caused by AMD. In a general way it can be applied to other sites where sulphide-rich waste-dumps are promoting the pollution of superficial water through the generation of AMD

A discrete geometric model of concurrent program execution

A trace of the execution of a concurrent object-oriented program can be displayed in two-dimensions as a diagram of a non-metric finite geometry. The actions of a programs are represented by points, its objects and threads by vertical lines, its transactions by horizontal lines, its communications and resource sharing by sloping arrows, and its partial traces by rectangular figures. We prove informally that the geometry satisfies the laws of Concurrent Kleene Algebra (CKA); these describe and justify the interleaved implementation of multithreaded programs on computer systems with a lesser number of concurrent processors. More familiar forms of semantics (e.g., verification-oriented and operational) can be derived from CKA. Programs are represented as sets of all their possible traces of execution, and non-determinism is introduced as union of these sets. The geometry is extended to multiple levels of abstraction and granularity; a method call at a higher level can be modelled by a specification of the method body, which is implemented at a lower level. The final section describes how the axioms and definitions of the geometry have been encoded in the interactive proof tool Isabelle, and reports on progress towards automatic checking of the proofs in the paper

Thai visitors’ expectations and experiences of explainer interaction within a science museum context

© The Author(s) 2015. In Western literature, there is evidence that museum explainers offer significant potential for enhancing visitors’ learning through influencing their knowledge, content, action, behaviour and attitudes. However, little research has focused on the role of explainers in other cultural contexts. This study explored interactions between visitors and museum explainers within the setting of Thailand. Two questionnaires were distributed to 600 visitors and 41 museum explainers. The results demonstrated both potential similarities and differences with Western contexts. Explainers appeared to prefer didactic approaches, focussing on factual knowledge rather than encouraging deep learning. Two-way communication, however, appeared to be enhanced by the use of a ‘pseudo-sibling relationship’ by explainers. Traditional Thai social reserve was reduced through such approaches, with visitors taking on active learning roles. These findings have implications for training museum explainers in non-Western cultures, as well as museum communication practice more generally