183 research outputs found

    On Colorful Bin Packing Games

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    We consider colorful bin packing games in which selfish players control a set of items which are to be packed into a minimum number of unit capacity bins. Each item has one of m2m\geq 2 colors and cannot be packed next to an item of the same color. All bins have the same unitary cost which is shared among the items it contains, so that players are interested in selecting a bin of minimum shared cost. We adopt two standard cost sharing functions: the egalitarian cost function which equally shares the cost of a bin among the items it contains, and the proportional cost function which shares the cost of a bin among the items it contains proportionally to their sizes. Although, under both cost functions, colorful bin packing games do not converge in general to a (pure) Nash equilibrium, we show that Nash equilibria are guaranteed to exist and we design an algorithm for computing a Nash equilibrium whose running time is polynomial under the egalitarian cost function and pseudo-polynomial for a constant number of colors under the proportional one. We also provide a complete characterization of the efficiency of Nash equilibria under both cost functions for general games, by showing that the prices of anarchy and stability are unbounded when m3m\geq 3 while they are equal to 3 for black and white games, where m=2m=2. We finally focus on games with uniform sizes (i.e., all items have the same size) for which the two cost functions coincide. We show again a tight characterization of the efficiency of Nash equilibria and design an algorithm which returns Nash equilibria with best achievable performance

    SESAME: Semantic Editing of Scenes by Adding, Manipulating or Erasing Objects

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    Recent advances in image generation gave rise to powerful tools for semantic image editing. However, existing approaches can either operate on a single image or require an abundance of additional information. They are not capable of handling the complete set of editing operations, that is addition, manipulation or removal of semantic concepts. To address these limitations, we propose SESAME, a novel generator-discriminator pair for Semantic Editing of Scenes by Adding, Manipulating or Erasing objects. In our setup, the user provides the semantic labels of the areas to be edited and the generator synthesizes the corresponding pixels. In contrast to previous methods that employ a discriminator that trivially concatenates semantics and image as an input, the SESAME discriminator is composed of two input streams that independently process the image and its semantics, using the latter to manipulate the results of the former. We evaluate our model on a diverse set of datasets and report state-of-the-art performance on two tasks: (a) image manipulation and (b) image generation conditioned on semantic labels

    Fluctuations of company yearly profits versus scaled revenue: Fat tail distribution of Levy type

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    We analyze annual revenues and earnings data for the 500 largest-revenue U.S. companies during the period 1954-2007. We find that mean year profits are proportional to mean year revenues, exception made for few anomalous years, from which we postulate a linear relation between company expected mean profit and revenue. Mean annual revenues are used to scale both company profits and revenues. Annual profit fluctuations are obtained as difference between actual annual profit and its expected mean value, scaled by a power of the revenue to get a stationary behavior as a function of revenue. We find that profit fluctuations are broadly distributed having approximate power-law tails with a Levy-type exponent α1.7\alpha \simeq 1.7, from which we derive the associated break-even probability distribution. The predictions are compared with empirical data.Comment: 6 pages, 6 figure

    Repair of gaps opposite lesions by homologous recombination in mammalian cells

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    Damages in the DNA template inhibit the progression of replication, which may cause single-stranded gaps. Such situations can be tolerated by translesion DNA synthesis (TLS), or by homology-dependent repair (HDR), which is based on transfer or copying of the missing information from the replicated sister chromatid. Whereas it is well established that TLS plays an important role in DNA damage tolerance in mammalian cells, it is unknown whether HDR operates in this process. Using a newly developed plasmid-based assay that distinguishes between the three mechanisms of DNA damage tolerance, we found that mammalian cells can efficiently utilize HDR to repair DNA gaps opposite an abasic site or benzo[a]pyrene adduct. The majority of these events occurred by a physical strand transfer (homologous recombination repair; HRR), rather than a template switch mechanism. Furthermore, cells deficient in either the human RAD51 recombination protein or NBS1, but not Rad18, exhibited decreased gap repair through HDR, indicating a role for these proteins in DNA damage tolerance. To our knowledge, this is the first direct evidence of gap-lesion repair via HDR in mammalian cells, providing further molecular insight into the potential activity of HDR in overcoming replication obstacles and maintaining genome stability

    Caffeine vs. carbamazepine as indicators of wastewater pollution in a karst aquifer

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    This paper presents the analysis of caffeine and carbamazepine transport in the subsurface as a result of wastewater release in the Sorek creek over the outcrops of the carbonate, Yarkon-Taninim, aquifer in Israel. Both caffeine and carbamazepine were used as indicators of sewage contamination in the subsurface. While carbamazepine is considered conservative, caffeine is subject to sorption and degradation. The objective of the study was to quantify differences in their transport under similar conditions in the karst aquifer. Water flow and pollutant transport in a “vadose zone–aquifer” system were simulated by a quasi-3-D dual permeability numerical model. The results of this study show that each of these two pollutants can be considered effective tracers for characterization and assessment of aquifer contamination. Carbamazepine was found to be more suitable for assessing the contamination boundaries, while caffeine can be used as a contaminant tracer only briefly after contamination occurs. In instances where there are low concentrations of carbamazepine which appear as background contamination in an aquifer, caffeine might serve as a better marker for detecting new contamination events, given its temporal nature. The estimated caffeine degradation rate and the distribution coefficient of a linear sorption isotherm were 0.091&thinsp;d−1 and 0.1&thinsp;L&thinsp;kg−1, respectively, which imply a high attenuation capacity. The results of the simulation indicate that by the end of the year most of the carbamazepine mass (approximately 95&thinsp;%) remained in the matrix of the vadose zone, while all of the caffeine was completely degraded a few months after the sewage was discharged.</p

    Biomolecular Filters for Improved Separation of Output Signals in Enzyme Logic Systems Applied to Biomedical Analysis

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    Biomolecular logic systems processing biochemical input signals and producing "digital" outputs in the form of YES/NO were developed for analysis of physiological conditions characteristic of liver injury, soft tissue injury and abdominal trauma. Injury biomarkers were used as input signals for activating the logic systems. Their normal physiological concentrations were defined as logic-0 level, while their pathologically elevated concentrations were defined as logic-1 values. Since the input concentrations applied as logic 0 and 1 values were not sufficiently different, the output signals being at low and high values (0, 1 outputs) were separated with a short gap making their discrimination difficult. Coupled enzymatic reactions functioning as a biomolecular signal processing system with a built-in filter property were developed. The filter process involves a partial back-conversion of the optical-output-signal-yielding product, but only at its low concentrations, thus allowing the proper discrimination between 0 and 1 output values

    Assessment of insulin resistance by a 13C glucose breath test: a new tool for early diagnosis and follow-up of high-risk patients

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    <p>Abstract</p> <p>Background/Aims</p> <p>Insulin resistance (IR) plays an important role in the pathogenesis of diabetes and non-alcoholic fatty liver disease (NAFLD). Current methods for insulin resistance detection are cumbersome, or not sensitive enough for early detection and follow-up. The BreathID<sup>® </sup>system can continuously analyse breath samples in real-time at the point-of-care. Here we determined the efficacy of the BreathID<sup>® </sup>using the <sup>13</sup>C-Glucose breath test (GBT) for evaluation of insulin resistance.</p> <p>Methods</p> <p>Twenty healthy volunteers were orally administered 75 mg of <sup>13</sup>C-glucose 1-<sup>13</sup>C. An oral glucose tolerance test (OGTT) was performed immediately; followed by serum glucose and insulin level determinations using GBT. GBT and OGTT were repeated following exercise, which alters insulin resistance levels.</p> <p>Results</p> <p>Within-subject correlations of GBT parameters with serum glucose and serum insulin levels were high. Before and after exercise, between-subjects correlations were high between the relative insulin levels and the % dose recoveries at 90 min (PDR 90), and the cumulative PDRs at 60 min (CPDR 60). Pairwise correlations were identified between pre-exercise Homeostasis Model Assessment (HOMA) IR at 90 min and PDR 90; HOMA B (for beta cell function) 120 and CPDR 30; HOMA IR 60 and peak time post-exercise; and HOMA B 150 with PDR 150.</p> <p>Conclusions</p> <p>The non-invasive real-time BreathID<sup>® </sup>GBT reliably assesses changes in liver glucose metabolism, and the degree of insulin resistance. It may serve as a non-invasive tool for early diagnosis and follow up of patients in high-risk groups.</p

    Reconstruction of Cell Lineage Trees in Mice

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    The cell lineage tree of a multicellular organism represents its history of cell divisions from the very first cell, the zygote. A new method for high-resolution reconstruction of parts of such cell lineage trees was recently developed based on phylogenetic analysis of somatic mutations accumulated during normal development of an organism. In this study we apply this method in mice to reconstruct the lineage trees of distinct cell types. We address for the first time basic questions in developmental biology of higher organisms, namely what is the correlation between the lineage relation among cells and their (1) function, (2) physical proximity and (3) anatomical proximity. We analyzed B-cells, kidney-, mesenchymal- and hematopoietic-stem cells, as well as satellite cells, which are adult skeletal muscle stem cells isolated from their niche on the muscle fibers (myofibers) from various skeletal muscles. Our results demonstrate that all analyzed cell types are intermingled in the lineage tree, indicating that none of these cell types are single exclusive clones. We also show a significant correlation between the physical proximity of satellite cells within muscles and their lineage. Furthermore, we show that satellite cells obtained from a single myofiber are significantly clustered in the lineage tree, reflecting their common developmental origin. Lineage analysis based on somatic mutations enables performing high resolution reconstruction of lineage trees in mice and humans, which can provide fundamental insights to many aspects of their development and tissue maintenance
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