Probably Approximately Symmetric: Fast Rigid Symmetry Detection With Global Guarantees

We present a fast algorithm for global rigid symmetry detection with approximation guarantees. The algorithm is guaranteed to find the best approximate symmetry of a given shape, to within a user‐specified threshold, with very high probability. Our method uses a carefully designed sampling of the transformation space, where each transformation is efficiently evaluated using a sublinear algorithm. We prove that the density of the sampling depends on the total variation of the shape, allowing us to derive formal bounds on the algorithm's complexity and approximation quality. We further investigate different volumetric shape representations (in the form of truncated distance transforms), and in such a way control the total variation of the shape and hence the sampling density and the runtime of the algorithm. A comprehensive set of experiments assesses the proposed method, including an evaluation on the eight categories of the COSEG data set. This is the first large‐scale evaluation of any symmetry detection technique that we are aware of.     

Combinatorial synthesis approach employing graph networks

The paper proposes a methodology to assist the designer at the initial stages of the design synthesis process by enabling him/her to employ knowledge and algorithms existing in graph network theory. The proposed method comprises three main stages: transforming the synthesis problem into a graph theoretic problem; devising the topology possessing special engineering properties corresponding to the system requirements; finding the geometric configuration of that topology that will possess the desired properties. To clarify the idea and to demonstrate its generality, the approach is presented through three synthesis case studies from different engineering domains: electrical networks, statics and kinematics.As is highlighted in the paper, the approach of employing graph theory in the synthesis process offers several unique advantages. Among these advantages are: gaining a general perspective on different synthesis problems from different engineering domains by transforming them into the same graph problem; employing the same graph algorithms for different synthesis problems; establishing the existence of configurations with special properties solely from the topology of the system; transferring knowledge and methods between different engineering disciplines for both the topology and the geometry generation steps.     

Linear Time Algorithms for Finding a Dominating Set of Fixed Size in Degenerated Graphs

There is substantial literature dealing with fixed parameter algorithms for the dominating set problem on various families of graphs. In this paper, we give a k ^O(dk) n time algorithm for finding a dominating set of size at most k in a d-degenerated graph with n vertices. This proves that the dominating set problem is fixed-parameter tractable for degenerated graphs. For graphs that do not contain K _h as a topological minor, we give an improved algorithm for the problem with running time (O(h)) ^hk n. For graphs which are K _h -minor-free, the running time is further reduced to (O(log h)) ^hk/2 n. Fixed-parameter tractable algorithms that are linear in the number of vertices of the graph were previously known only for planar graphs. For the families of graphs discussed above, the problem of finding an induced cycle of a given length is also addressed. For every fixed H and k, we show that if an H-minor-free graph G with n vertices contains an induced cycle of size k, then such a cycle can be found in O(n) expected time as well as in O(nlog n) worst-case time. Some results are stated concerning the (im)possibility of establishing linear time algorithms for the more general family of degenerated graphs. A preliminary version of this paper appeared in the Proceedings of the 13th Annual International Computing and Combinatorics Conference (COCOON), Banff, Alberta, Canada (2007), pp. 394–405. N. Alon research supported in part by a grant from the Israel Science Foundation, and by the Hermann Minkowski Minerva Center for Geometry at Tel Aviv University. This paper forms part of a Ph.D. thesis written by S. Gutner under the supervision of Prof. N. Alon and Prof. Y. Azar in Tel Aviv University.     

Missing value estimation of microarray data using Sim-GAN

Knowledge and Information Systems - Microarray data analysis needs utmost care as it plays a significant role in cancer study. Due to the excessive complexity of the data extraction process, it...     

A single center,open‐label,randomized, parallel group study assessing the relationship between asymptomatic bacteriuria and inflammation in maintenance hemodialysis patients

Introduction: The significance of asymptomatic bacteriuria in maintenance hemodialysis (MHD) patients remains controversial. We hypothesized that the presence of asymptomatic bacteriuria as a sole clinical manifestation of urinary tract infection (UTI) in asymptomatic MHD patient may contribute to the chronic inflammatory response. Our aim was to explore the relationship between asymptomatic bacteriuria and elevated levels of inflammatory markers in MHD patients. Methods: A randomized open‐label single center study of 114 MHD patients was conducted. Forty‐six patients presented negative urine culture and 41 subjects were excluded due to different reasons. The remaining 27 patients (mean age of 71.5 ± 12.2 years, 63% men), fulfilling the criteria for having asymptomatic bacteriuria, were randomly assigned to either the treatment group (13 patients) or the observational group (14 subjects). The treatment group received 7 days of antibiotic treatment given according to bacteriogram sensitivity. After 3 months of follow‐up all measurements of the study were repeated. The primary end point was change in inflammatory biomarkers from baseline by the end of the study. Findings: There were no statistically significant differences in white blood cell changes (P = 0.27), ferritin (P = 0.09), C‐reactive protein (P = 0.90), and interleukin‐6 (P = 0.14) levels between the groups from baseline to the end of study or at the end of the study. Analyzing cross‐sectional data, asymptomatic bacteriuria was found to not be a predictor of higher levels of inflammatory parameters at baseline. Discussion: Asymptomatic bacteriuria is not a modifiable risk factor for chronic inflammation in the MHD population.     

Levels of consumers’ agency and capacity as predictors for electricity demand reduction in the residential sector

A field study of 50 households in a collective community in Israel provides initial support for the hypotheses about the relations between actors’ agency, capacity and electricity demand reduction. ‘Agency’ refers to actors’ willingness and ability to make their own free choices and ‘capacity’ refers to actors’ ability to perform the choices they made. According to the hypotheses, change is more likely to happen when actors’ levels of agency and capacity are high; unlikely to happen when the levels are low and uncertain when there is a mismatch between levels of agency and capacity (one is high and the other low). In the research, levels of agency and capacity regarding 11 energy saving actions were self-reported and electricity consumption was metered before and during energy saving campaign. Findings show that levels of agency were lower than those of capacity for no-cost actions which require high engagement, while levels of capacity were lower than those of agency for high-cost action which require low engagement. In addition, households with high agency and high capacity reduced their electricity consumption by 9.39 % (on average); those with low agency and low capacity increased their consumption by 6.67 %; and those with a mismatch between agency and capacity reduced their consumption by 1.91 %.     

Immediate Effects of Nectar Robbing by Palestine Sunbirds (Nectarinia osea) on Nectar Alkaloid Concentrations in Tree Tobacco (Nicotiana glauca)

Plant secondary metabolites (PSMs), such as alkaloids, are often found in many parts of a plant, including flowers, providing protection to the plant from various types of herbivores or microbes. PSMs are also present in the floral nectar of many species, but typically at lower concentrations than in other parts of the plant. Nectar robbers often damage floral tissue to access the nectar. By doing so, these nectar robbers may initiate an increase of PSMs in the floral nectar. It is often assumed that it takes at least a few hours before the plant demonstrates an increase in PSMs. Here, we addressed the question of whether PSMs in the floral tissue are immediately being released into the floral nectar following nectar robbing. To address this research question, we investigated whether there was an immediate effect of nectar robbing by the Palestine Sunbird (Nectarinia osea) on the concentration of nectar alkaloids, nicotine and anabasine, in Tree Tobacco (Nicotiana glauca). We found that the concentration of anabasine, but not nicotine, significantly increased in floral nectar immediately following simulated nectar robbing. These findings suggest that nectar robbers could be ingesting greater amounts of PSMs than they would if they visit flowers legitimately. As a consequence, increased consumption of neurotoxic nectar alkaloids or other PSMs could have negative effects on the nectar robber.     

Environmentally defined frames of reference: Their time course and sensitivity to spatial cues and attention.

In a Simon task the effects of spatial cues and attention on spatial stimulus coding were explored. Participants made speeded responses corresponding to the direction of target arrows that were preceded by peripherally presented cues. Cue validity varied across experiments as did the percentage of trials on which the target appeared peripherally or centrally. The data indicate (a) that targets are coded relative to multiple reference frames, (b) that spatial coding of a target is not affected when attention is shifted to the target, and (c) that an object serves as a referent for spatial coding of other objects even after its spatial code no longer activates responses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dissolution kinetics and solubility limit of CaF2 in molten KCl–NaCl salt

The interaction between NaCl–KCl salt of an equimolar composition and CaF₂ was investigated in the 1023–1123 K temperature range. The solubility limit was determined as 2.1, 2.5, and 3.4 mol.% for 1023, 1073, and 1123 K, respectively. The linear dependence of the specific weight loss with time and the activation energy of the dissolution (124.6 ± 8.7 kJ/mol) indicate that CaF₂ dissociation of the ions is the limiting stage of the process. Thermodynamic properties (partial enthalpy and entropy) of CaF₂ in a dilute ternary –NaCl–KCl–CaF₂ liquid solution were estimated using the values of the solubility limit and by applying a regular solution approach.     

NUMERICAL CALCULATIONS FOR COMBINED CONDUCTION AND RADIATION TRANSIENT HEAT TRANSFER IN A SEMITRANSPARENT MEDIUM

A numerical computer code was developed for calculating the combined conduction and radiation transient heat transfer in cylindrical, semitransparent materials that have temperature-dependent thermal properties. The radiative component is combined with the equation of conduction heat transfer by adding it as a heat source. The finite element method (FEM) was used for calculating the radiative component and for solving the temperature field in the medium. Very good agreement was observed between results obtained by using our code and those that exist in the literature for several steady-state cases. The advantage of the code is due to the fact that it incorporates temperature-dependent properties; thus it leads to more realistic and accurate results. The code was applied to calculate the cooling path of a large cylindrical sapphire boule while using varying, transient, temperature-dependent, combined heat transfer coefficients.