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Search Results: 1 - 10 of 138567 matches for " K. Stola "
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Aplica??o de CFD para o cálculo de coeficientes de press?o externos nas aberturas de um edifício
stola, Daniel;Alucci, Marcia Peinado;
Ambiente Construído , 2011, DOI: 10.1590/S1678-86212011000100010
Abstract: pressure coefficients (cp) are a key parameter in the study of wind-driven natural ventilation in buildings. this paper reports the results of a research study aimed at evaluating the feasility of using cfd (computational fluid dynamics) to obtain cp data and also evaluating the importance of some of the aspects of the simulation setup in the results obtained. the following aspects are addressed: mesh independence, sensitivity to the wind profile and to the roughness of the domain floor. values of y+ are discussed, and surface-averaged cp values from the literature are compared to local cp calculated by cfd. the building used in the simulations is a 5 storey, isolated building, typically adopted in social housing projects in brazil. this paper concludes that cfd simulations are feasible and constitute an important alternative to obtain cp values when compared to wind tunnel experiments. however, differences in the simulation setup may lead to significant deviations in the results, both in absolute values (up to ± 0.5) and in relative values (up to 50%). the mesh independence test has proven to be fundamental for a reliable simulation. the same applies for the inlet wind profile definition. future work should focus on the validation of simulations.
Antimycobacterial Assessment of Salicylanilide Benzoates including Multidrug-Resistant Tuberculosis Strains
Martin Krátky,Jarmila Vin?ová,Ji?ina Stola?íková
Molecules , 2012, DOI: 10.3390/molecules171112812
Abstract: The increasing emergence especially of drug-resistant tuberculosis has led to a strong demand for new anti-tuberculosis drugs. Eighteen salicylanilide benzoates were evaluated for their inhibition potential against Mycobacterium tuberculosis, Mycobacterium avium and two strains of Mycobacterium kansasii; minimum inhibitory concentration values ranged from 0.5 to 16 μmol/L. The most active esters underwent additional biological assays. Four benzoates inhibited effectively the growth of five multidrug-resistant strains and one extensively drug-resistant strain of M. tuberculosis at low concentrations (0.25–2 μmol/L) regardless of the resistance patterns. The highest rate of multidrug-resistant mycobacteria inhibition expressed 4-chloro-2-[4-(trifluoromethyl)-phenylcarbamoyl]phenyl benzoate (0.25–1 μmol/L). Unfortunately, the most potent esters were still considerably cytotoxic, although mostly less than their parent salicylanilides.
J-PET analysis framework for the prototype TOF-PET detector
W. Krzemień,M. Silarski,K. Stola,D. Trybek,T. Bednarski,P. Bia?as,E. Czerwiński,?. Kap?on,A. Kochanowski,G. Korcyl,J. Kowal,P. Kowalski,T. Kozik,M. Molenda,P. Moskal,Sz. Nied?wiecki,M. Pa?ka,M. Pawlik,L. Raczyński,Z. Rudy,P. Salabura,N. G. Sharma,A. S?omski,J. Smyrski,A. Strzelecki,W. Wi?licki,M. Zieliński,N. Zoń
Physics , 2013, DOI: 10.1515/bams-2013-0109
Abstract: Novel TOF-PET scanner solutions demand, apart from the state of the art detectors, software for fast processing of the gathered data, monitoring of the whole scanner and reconstruction of the PET image. In this article we present an analysis framework for the novel STRIP-PET scanner developed by the J-PET collaboration in the Institute of Physics of the Jagiellonian University. This software is based on the ROOT package used in many particle physics experiments.
Overview of the software architecture and data flow for the J-PET tomography device
W. Krzemien,T. Bednarski,P. Bialas,E. Czerwinski,A. Gajos,A. Gruntowski,T. Gruntowski,L . Kaplon,A. Kochanowski,G. Korcyl,J. Kowal,P. Kowalski,T. Kozik,E. Kubicz,P. Moskal,Sz. Niedzwiecki,M. Palka,L. Raczynski,Z. Rudy,N. G. Sharma,M. Silarski,A. Slomski,K. Stola,A. Strzelecki,D. Trybek,A. Wieczorek,M. Zielinski,W. Wislicki,N. Zon
Physics , 2015,
Abstract: Modern TOF-PET scanner systems require high-speed computing resources for efficient data processing, monitoring and image reconstruction. In this article we present the data flow and software architecture for the novel TOF-PET scanner developed by the J-PET collaboration. We discuss the data acquisition system, reconstruction framework and some image reconstruction issues. Also, the concept of computing outside hospitals in the remote centers such as \'Swierk Computing Centre in Poland is presented.
Processing optimization with parallel computing for the J-PET tomography scanner
W. Krzemień,M. Ba?a,T. Bednarski,P. Bia?as,E. Czerwiński,A. Gajos,M. Gorgol,B. Jasińska,D. Kamińska,?. Kap?on,G. Korcyl,P. Kowalski,T. Kozik,E. Kubicz,Sz. Nied?wiecki,M. Pa?ka,L. Raczyński,Z. Rudy,O. Rundel,N. G. Sharma,M. Silarski,A. S?omski,K. Stola,A. Strzelecki,D. Trybek,Anna Wieczorek,W. Wi?licki,M. Zieliński,B. K. Zgardzińska,P. Moskal
Physics , 2015,
Abstract: The Jagiellonian-PET (J-PET) collaboration is developing a prototype TOF-PET detector based on long polymer scintillators. This novel approach exploits the excellent time properties of the plastic scintillators, which permit very precise time measurements. The very fast, FPGA-based front-end electronics and the data acquisition system, as well as, low- and high-level reconstruction algorithms were specially developed to be used with the J-PET scanner. The TOF-PET data processing and reconstruction are time and resource demanding operations, especially in case of a large acceptance detector, which works in triggerless data acquisition mode. In this article, we discuss the parallel computing methods applied to optimize the data processing for the J-PET detector. We begin with general concepts of parallel computing and then we discuss several applications of those techniques in the J-PET data processing.
Antimycobacterial Activity of Salicylanilide Benzenesulfonates
Martin Krátky,Jarmila Vin?ová,Nabila Guisado Rodriguez,Ji?ina Stola?íková
Molecules , 2012, DOI: 10.3390/molecules17010492
Abstract: A series of eighteen novel esters of salicylanilides with benzenesulfonic acid were designed, synthesized and characterized by IR, 1H-NMR and 13C-NMR. They were evaluated in vitro as potential antimycobacterial agents towards Mycobacterium tuberculosis, Mycobacterium avium and two strains of Mycobacterium kansasii. In general, the minimum inhibitory concentrations range from 1 to 500 μmol/L. The most active compound against M. tuberculosis was 4-chloro-2-(4-(trifluoromethyl)phenylcarbamoyl)-phenyl benzenesulfonate, with MIC of 1 μmol/L and towards M. kansasii its isomer 5-chloro-2-(4-(trifluoromethyl)phenylcarbamoyl)phenyl benzenesulfonate (MIC of 2–4 μmol/L). M. avium was the less susceptible strain. However, generally, salicylanilide benzenesulfonates did not surpass the activity of other salicylanilide esters with carboxylic acids.
Me a nobiru frakcijas un to īmiskais sastāvs prie u (Pinus sylvestris L.) audzē 2. līme a me a monitoringa parauglaukumā
Arta Bārdule , Andis Lazdi , Andis Bārdulis , Dagnija Lazdi a , Je ena Stola
Proceedings of the Latvia University of Agriculture , 2012, DOI: 10.2478/v10236-012-0003-4
Abstract: Forest monitoring is dated back to early 1980s, when a severe decline in tree crown condition and forest health occurred across large part of Europe. Foresters and scientists all over the Europe started to monitor indicators of forest health, including litterfall, in order to objectively describe changes in forest health. Since 1985, forest condition in Europe has been monitored within the scope of two-level system of ICP-Forests (International Co-operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests). General information on forest health is annually recorded on Level I monitoring sites, but more intensive investigations, including quantitative and qualitative characteristics of litterfall, are carried out in Level II sites. In Latvia, one Level II monitoring plot was established in a Scots pine (Pinus sylvestris L.) stand in Valgunde parish of the Jelgava municipality in 2004. Canopy litterfall is a significant pathway for return of nutrients to soil in a forest ecosystem and may provide important information as a phenological indicator of climate change effects on forests. The main objective of this study was to determine preliminary characteristics of nutrient return with litterfall. The quality and quantity of litterfall fractions in a Level II forest monitoring plot were investigated in 2009. The chemical elements involved into the study were nitrogen (N), calcium (Ca), potassium (K), magnesium (Mg), phosphorus (P), sulphur (S), and carbon (C).
On three measures of non-convexity
Josef Cibulka,Miroslav Korbelá?,Jan Kyn?l,Viola Mészáros,Rudolf Stola,Pavel Valtr
Mathematics , 2014,
Abstract: The invisibility graph $I(X)$ of a set $X \subseteq \mathbb{R}^d$ is a (possibly infinite) graph whose vertices are the points of $X$ and two vertices are connected by an edge if and only if the straight-line segment connecting the two corresponding points is not fully contained in $X$. We consider the following three parameters of a set $X$: the clique number $\omega(I(X))$, the chromatic number $\chi(I(X))$ and the convexity number $\gamma(X)$, which is the minimum number of convex subsets of $X$ that cover $X$. We settle a conjecture of Matou\v{s}ek and Valtr claiming that for every planar set $X$, $\gamma(X)$ can be bounded in terms of $\chi(I(X))$. As a part of the proof we show that a disc with $n$ one-point holes near its boundary has $\chi(I(X)) \ge \log\log(n)$ but $\omega(I(X))=3$. We also find sets $X$ in $\mathbb{R}^5$ with $\chi(X)=2$, but $\gamma(X)$ arbitrarily large.
Graph sharing games: complexity and connectivity
Josef Cibulka,Jan Kyn?l,Viola Mészáros,Rudolf Stola,Pavel Valtr
Computer Science , 2012, DOI: 10.1016/j.tcs.2012.12.029
Abstract: We study the following combinatorial game played by two players, Alice and Bob, which generalizes the Pizza game considered by Brown, Winkler and others. Given a connected graph G with nonnegative weights assigned to its vertices, the players alternately take one vertex of G in each turn. The first turn is Alice's. The vertices are to be taken according to one (or both) of the following two rules: (T) the subgraph of G induced by the taken vertices is connected during the whole game, (R) the subgraph of G induced by the remaining vertices is connected during the whole game. We show that if rules (T) and/or (R) are required then for every epsilon > 0 and for every positive integer k there is a k-connected graph G for which Bob has a strategy to obtain (1-epsilon) of the total weight of the vertices. This contrasts with the original Pizza game played on a cycle, where Alice is known to have a strategy to obtain 4/9 of the total weight. We show that the problem of deciding whether Alice has a winning strategy (i.e., a strategy to obtain more than half of the total weight) is PSPACE-complete if condition (R) or both conditions (T) and (R) are required. We also consider a game played on connected graphs (without weights) where the first player who violates condition (T) or (R) loses the game. We show that deciding who has the winning strategy is PSPACE-complete.
Solution of Peter Winkler's Pizza Problem
Josef Cibulka,Jan Kyn?l,Viola Mészáros,Rudolf Stola,Pavel Valtr
Computer Science , 2008, DOI: 10.1007/978-3-642-13580-4_4
Abstract: Bob cuts a pizza into slices of not necessarily equal size and shares it with Alice by alternately taking turns. One slice is taken in each turn. The first turn is Alice's. She may choose any of the slices. In all other turns only those slices can be chosen that have a neighbor slice already eaten. We prove a conjecture of Peter Winkler by showing that Alice has a strategy for obtaining 4/9 of the pizza. This is best possible, that is, there is a cutting and a strategy for Bob to get 5/9 of the pizza. We also give a characterization of Alice's best possible gain depending on the number of slices. For a given cutting of the pizza, we describe a linear time algorithm that computes Alice's strategy gaining at least 4/9 of the pizza and another algorithm that computes the optimal strategy for both players in any possible position of the game in quadratic time. We distinguish two types of turns, shifts and jumps. We prove that Alice can gain 4/9, 7/16 and 1/3 of the pizza if she is allowed to make at most two jumps, at most one jump and no jump, respectively, and the three constants are the best possible.
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