In the NP-hard Optimizing Phylogenetic Diversity with Dependencies (PDD) problem, the input consists of a phylogenetic tree T over a set of taxa X, a food-web that describes the prey-predator relationships in X, and i...
详细信息
The construction of perfect hash functions is a well-studied topic. In this article, this concept is generalized with the following definition. We say that a family of functions from [n] to [k] is a delta-balanced (n,...
详细信息
The construction of perfect hash functions is a well-studied topic. In this article, this concept is generalized with the following definition. We say that a family of functions from [n] to [k] is a delta-balanced (n, k)-family of perfect hash functions if for every S subset of [n], vertical bar S vertical bar = k, the number of functions that are 1-1 on S is between T/delta and delta T for some constant T > 0. The standard definition of a family of perfect hash functions requires that there will be at least one function that is 1-1 on S, for each S of size k. In the new notion of balanced families, we require the number of 1-1 functions to be almost the same ( taking delta to be close to 1) for every such S. Our main result is that for any constant delta > 1, a delta-balanced (n, k)-family of perfect hash functions of size 2(O(k) (log) (log k)) log n can be constructed in time 2(O(k log log k)) log n. Using the technique of color-coding we can apply our explicit constructions to devise approximation algorithms for various counting problems in graphs. In particular, we exhibit a deterministic polynomial-time algorithm for approximating both the number of simple paths of length k and the number of simple cycles of size k for any k <= O(log n/log log log n) graph with n vertices. The approximation is up to any fixed desirable relative error.
We study the parameterized complexity of the problems of determining whether a graph contains a k-edge subgraph (k-vertex induced subgraph) that is a Pi-graph for Pi-graphs being one of the following four classes of g...
详细信息
We study the parameterized complexity of the problems of determining whether a graph contains a k-edge subgraph (k-vertex induced subgraph) that is a Pi-graph for Pi-graphs being one of the following four classes of graphs: Eulerian graphs, even graphs, odd graphs, and connected odd graphs. We also consider the parameterized complexity of their parametric dual problems. For these sixteen problems, we show that eight of them are fixed parameter tractable and four are W[1]-hard. Our main techniques are the color-coding method of Alon, Yuster and Zwick, and the random separation method of Cai, Chan and Chan. (C) 2011 Elsevier B.V. All rights reserved.
Although many new methodological and modelling concepts have been proposed by the scientific community, current industries are still focusing their engineering design process on CAD model since they assume it is the s...
详细信息
Although many new methodological and modelling concepts have been proposed by the scientific community, current industries are still focusing their engineering design process on CAD model since they assume it is the starting point of many analyses with respect to product life cycle (CAM, FEA, LCA…). The paper presents the application of modelling concepts that lead the progressive justification of CAD model with respect to knowledge synthesis by least commitment. Design experts are first formalizing their knowledge that is therefore translated to form features and parameters (topology, position, orientation, dimensions…). The results show that this new design approach and models support design intents and rational, but the generated CAD model is not fully justified. That drives to many conclusions: CAD model is many often non-100% rational by designers’ knowledge, design solution space is therefore larger than the one modelled in CAD software and could be used to foster innovation.
Background To analyze the benefit of color-coded summation images in the assessment of target lumen perfusion in patients with aortic dissection and malperfusion syndrome before and after fluoroscopy-guided aortic fen...
详细信息
Background To analyze the benefit of color-coded summation images in the assessment of target lumen perfusion in patients with aortic dissection and malperfusion syndrome before and after fluoroscopy-guided aortic fenestration. Methods Between December 2011 and April 2020 25 patients with Stanford type A (n = 13) or type B dissection (n = 12) and malperfusion syndromes were treated with fluoroscopy-guided fenestration of the dissection flap using a re-entry catheter. The procedure was technically successful in 100% of the cases and included additional iliofemoral stent implantation in four patients. Intraprocedural systolic blood pressure measurements for gradient evaluation were performed in 19 cases. Post-processed color-coded DSA images were obtained from all DSA series before and following fenestration. Differences in time to peak (dTTP) values in the compromised aortic lumen and transluminal systolic blood pressure gradients were analyzed retrospectively. Correlation analysis between dTTP and changes in blood pressure gradients was performed. Results Mean TTP prior to dissection flap fenestration was 6.85 +/- 1.35 s. After fenestration, mean TTP decreased significantly to 4.96 +/- 0.94 s (p < 0.001). Available systolic blood pressure gradients between the true and the false lumen were reduced by a median of 4.0 mmHg following fenestration (p = 0.031), with significant reductions in Stanford type B dissections (p = 0.013) and minor reductions in type A dissections (p = 0.530). A moderate correlation with no statistical significance was found between dTTP and the difference in systolic blood pressure (r = 0.226;p = 0.351). Conclusions Hemodynamic parameters obtained from color-coded DSA confirmed a significant reduction of TTP values in the aortic target lumen in terms of an improved perfusion in the compromised aortic region. color-coded DSA might thus be a suitable complementary tool in the assessment of complex vascular patterns prevailing in aortic dissection
This study examines the mechanisms and expertise of color-based method implementation in a present-day academic process and different forms of learning. This study aimed to identify the effectiveness of color educatio...
详细信息
This study examines the mechanisms and expertise of color-based method implementation in a present-day academic process and different forms of learning. This study aimed to identify the effectiveness of color education in the study of the humanities (history of Ukraine) for medical students. The research methodology included structural and logical methods, questionnaire methods, observations, and descriptive and statistical methods. The research results include an identified system of effective parameters, forms, and techniques of color education used in the academic process as well as its impact on the quality of education services provided under blended learning conditions. The color-coding culture parameter color-coding culture of important text segments ranked first among the seven techniques to activate mental activity and memory retention intensification. colorcoding has become medical students' most effective method of remembering information. color-based methods in the teaching of humanities are an effective method for improving the quality of students' learning and allow for better memorization of learning materials, especially in distance learning environments. Prospects for introducing pedagogical innovations in higher education include improving and developing educational materials using color effects to improve student perceptions. The research can be applied to the educational process for students of various specialties and the study of different disciplines.
FUCCI color codes cells as they express different color fluorescent proteins as they go through phases of the cell cycle. The cell cycle phase distribution of cancer cells in Gelfoam® histoculture was similar to ...
详细信息
FUCCI color codes cells as they express different color fluorescent proteins as they go through phases of the cell cycle. The cell cycle phase distribution of cancer cells in Gelfoam® histoculture was similar to in vivo tumors, whereby only the surface cells proliferate and interior cells are quiescent in G0/G1. In contrast, in 2D cancer-cell culture, most of the cells are always cycling. The cancer cells responded similarly to toxic chemotherapy in Gelfoam® culture as in vivo; as such, therapy is cell cycle dependent. In 2D culture, cancer cells were much more chemosensitive. These results indicate why the drug response pattern of tumors in Gelfoam® histoculture reflects what is observed in vivo. less
暂无评论