On the probabilistic min spanning tree Problem

We study a probabilistic optimization model for min spanning tree, where any vertex vi of the input-graph G(V,E) has some presence probability pi in the final instance G′ ⊂ G that will effectively be optimized. Suppose that when this “real” instance G′ becomes known, a spanning tree T, called anticipatory or a priori spanning tree, has already been computed in G and one can run a quick algorithm (quicker than one that recomputes from scratch), called modification strategy, that modifies the anticipatory tree T in order to fit G ′. The goal is to compute an anticipatory spanning tree of G such that, its modification for any G ′ ⊆ G is optimal for G ′. This is what we call probabilistic min spanning tree problem. In this paper we study complexity and approximation of probabilistic min spanning tree in complete graphs under two distinct modification strategies leading to different complexity results for the problem. For the first of the strategies developed, we also study two natural subproblems of probabilistic min spanning tree, namely, the probabilistic metric min spanning tree and the probabilistic min spanning tree 1,2 that deal with metric complete graphs and complete graphs with edge-weights either 1, or 2, respectively

Algorithm Engineering in Robust Optimization

Robust optimization is a young and emerging field of research having received a considerable increase of interest over the last decade. In this paper, we argue that the the algorithm engineering methodology fits very well to the field of robust optimization and yields a rewarding new perspective on both the current state of research and open research directions. To this end we go through the algorithm engineering cycle of design and analysis of concepts, development and implementation of algorithms, and theoretical and experimental evaluation. We show that many ideas of algorithm engineering have already been applied in publications on robust optimization. Most work on robust optimization is devoted to analysis of the concepts and the development of algorithms, some papers deal with the evaluation of a particular concept in case studies, and work on comparison of concepts just starts. What is still a drawback in many papers on robustness is the missing link to include the results of the experiments again in the design

Quantitative imaging of concentrated suspensions under flow

We review recent advances in imaging the flow of concentrated suspensions, focussing on the use of confocal microscopy to obtain time-resolved information on the single-particle level in these systems. After motivating the need for quantitative (confocal) imaging in suspension rheology, we briefly describe the particles, sample environments, microscopy tools and analysis algorithms needed to perform this kind of experiments. The second part of the review focusses on microscopic aspects of the flow of concentrated model hard-sphere-like suspensions, and the relation to non-linear rheological phenomena such as yielding, shear localization, wall slip and shear-induced ordering. Both Brownian and non-Brownian systems will be described. We show how quantitative imaging can improve our understanding of the connection between microscopic dynamics and bulk flow.Comment: Review on imaging hard-sphere suspensions, incl summary of methodology. Submitted for special volume 'High Solid Dispersions' ed. M. Cloitre, Vol. xx of 'Advances and Polymer Science' (Springer, Berlin, 2009); 22 pages, 16 fig

Criticality Analysis of Activity Networks under Interval Uncertainty

Dedicated to the memory of Professor Stefan Chanas - The extended abstract version of this paper has appeared in Proceedings of 11th International Conference on Principles and Practice of Constraint Programming (CP2005) ("Interval Analysis in Scheduling", Fortin et al. 2005)International audienceThis paper reconsiders the Project Evaluation and Review Technique (PERT) scheduling problem when information about task duration is incomplete. We model uncertainty on task durations by intervals. With this problem formulation, our goal is to assert possible and necessary criticality of the different tasks and to compute their possible earliest starting dates, latest starting dates, and floats. This paper combines various results and provides a complete solution to the problem. We present the complexity results of all considered subproblems and efficient algorithms to solve them

Состояние легочной микробиоты у мышей С57bl/6 в модели экспериментального туберкулеза

The objective: to study the changes in the lung microbiota in inbred C57BL/6 mice after aerogenic infection with M. tuberculosis in an experimental tuberculosis model.Subjects and Methods. This study was carried out on 20 female mice of inbred line C57BL/6 weighing 20-22 grams which were infected in a Glas-Col aerosol chamber (USA) with the culture of M. tuberculosis of virulent strain H37Rv at the dose of 400 CFU/lung. Morphological and microbiological assessment of the lungs state was performed before (day 0) (n=5) and 7 (n=5), 30 (n=5) and 60 (n=5) days after the infection. The results obtained were subjected to statistical processing using ANOVA test and Student t-test.Results. 7, 30, and 60 days after aerosol infection with M. tuberculosis against the background of successive morphological and microbiological changes typical of the experimental tuberculosis model, we established an imbalance of bacterial population in the lung microbiota. Before infection with M. tuberculosis, a scanty biotope was recorded with a predominance of lactobacilli –Lactobacillus murinus, Lactobacillus apodeme. 7, 30 and 60 days after infection with M. tuberculosis, consistent changes were recorded, such as increase in the number and diversity of the bacterial population. The most indicative markers of the recorded imbalance were: Streptococcus thoraltensis, Streptococcus acidominiminus, Arthrobacter crystallopoietes, Staphylococcus hominis, Micrococcus luteus.Conclusion. Tuberculosis infection is a significant factor affecting the state of the lung microbiota. With increased duration of the infection with M. tuberculosis, imbalance of the bacterial flora is formed in the lungs of C57BL/6 mice, accompanied by characteristic tissue inflammation and growing mycobacterial load.Цель исследования: изучить динамику изменений в микробиоте легких у инбредных мышей C57BL/6 после аэрогенного инфицирования M. tuberculosis в модели экспериментального туберкулеза.Материалы и методы. Настоящая работа выполнена на 20 самках мышей инбредной линии C57BL/6, массой 20–22 грамм, которые были заражены в аэрозольной камере Glas-Col (США) культурой Мtb вирулентного штамма H37Rv в дозе 400 КОЕ/легкое. Морфологическую и микробиологическую оценку состояния легких проводили до (день 0) (n=5) и через 7 (n=5), 30 (n=5) и 60 (n=5) дней после инфицирования. Полученные результаты подвергали статистической обработке с использованием теста ANOVA и Стьюдент t-теста.Результаты. Через 7, 30 и 60 дней после аэрозольного инфицирования M. tuberculosis, на фоне последовательных морфологических и микробиологических изменений, характерных для модели экспериментального туберкулеза, нами установлен дисбаланс бактериальной флоры в микробиоте легких. До заражения Mtb регистрировали скудный биотоп с преобладанием лактобацилл – Lactobacillus murinus, Lactobacillus apodeme. Через 7, 30 и 60 дней после инфицирования Mtb регистрировали последовательные изменения в виде увеличения количества и разнообразия бактериального сообщества. Наиболее показательными маркерами регистрируемого дисбаланса были: Streptococcus thoraltensis, Streptococcus acidominiminus, Arthrobacter crystallopoietes, Staphylococcus hominis, Micrococcus luteus.Заключение. Туберкулезная инфекция является значимым фактором, воздействующим на состояние микробиоты легких.С увеличением длительности инфицирования Mtb в легких мышей C57BL/6 формируется дисбаланс бактериальной флоры, сопровождающийся характерным тканевым воспалением и нарастанием микобактериальной нагрузки

Макрофагальный и цитокиновый спектры бронхоальвеолярного смыва при впервые выявленном и рецидивирующем саркоидозе органов дыхания

Goal of the study: to investigate structural and functional specific features of macrophages and cytokine profiles of bronchoalveolar lavage in new and relapsing respiratory sarcoidosis (RS).Materials and methods. The study included comparative light optical and electronic microscopic examinations of macrophages, macrophage formula and cytokine profile of bronchoalveolar lavage in 120 patients suffering from different forms of RS. It was found that in case of new RS mostly macrophages of M1 phenotype were detected in the lavage. They had high level of IL-8, IL-2, IL-1β production and ultrastructural signs of hypersecretion which was especially typical of platycytes. High level of IL-4, IL-5 content is typical of relapsing sarcoidosis: additionally to macrophages of M1 phenotype, there are macrophages of M2 phenotype with ultrastructural signs of phagocytic function which can be used for diagnostics of this form of RS.Цель исследования: изучить структурно-функциональные особенности макрофагов и цитокиновый спектр бронхоальвеолярного лаважа при впервые выявленном и рецидивирующем саркоидозе органов дыхания (СОД).Материалы и методы. Проведено сравнительное светооптическое и электронно-микроскопическое изучение макрофагов, определены макрофагальная формула и цитокиновый спектр бронхоальвеолярного смыва у 120 больных с различными вариантами СОД. Показано, что при впервые выявленном СОД в лаваже определяются преимущественно макрофаги М1-фенотипа. Они отличаются высоким уровнем продукции IL-8, IL-2, IL-1β и ультраструктурными признаками гиперсекреции, что особенно характерно для эпителиоидных клеток. Для рецидивирующего саркоидоза характерно повышенное содержание IL-4, IL-5: помимо макрофагов с М1-фенотипом, появляются макрофаги М2-фенотипа с ультраструктурными признаками фагоцитарной функции, что может быть использовано в диагностике этой формы СОД