1,131 research outputs found

    Assessment of the effectiveness of head only and back-of-the-head electrical stunning of chickens

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    The study assesses the effectiveness of reversible head-only and back-of-the-head electrical stunning of chickens using 130–950 mA per bird at 50 Hz AC

    Simulation Subsumption or Déjà vu on the Web

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    Simulation unification is a special kind of unification adapted to retrieving semi-structured data on the Web. This article introduces simulation subsumption, or containment, that is, query subsumption under simulation unification. Simulation subsumption is crucial in general for query optimization, in particular for optimizing pattern-based search engines, and for the termination of recursive rule-based web languages such as the XML and RDF query language Xcerpt. This paper first motivates and formalizes simulation subsumption. Then, it establishes decidability of simulation subsumption for advanced query patterns featuring descendant constructs, regular expressions, negative subterms (or subterm exclusions), and multiple variable occurrences. Finally, we show that subsumption between two query terms can be decided in O(n!n) where n is the sum of the sizes of both query terms

    Therapeutic potential and challenges of natural killer cells in treatment of solid tumors

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    Natural killer (NK) cells are innate lymphoid cells that hold tremendous potential for effective immunotherapy for a broad range of cancers. Due to the mode of NK cell killing, requiring one-to-one target engagement and site-directed release of cytolytic granules, the therapeutic potential of NK cells has been most extensively explored in hematological malignancies. However, their ability to precisely kill antibody coated cells, cancer stem cells, and genotoxically altered cells, while maintaining tolerance to healthy cells makes them appealing therapeutic effectors for all cancer forms, including metastases. Due to their release of pro-inflammatory cytokines, NK cells may potently reverse the anti-inflammatory tumor microenvironment (TME) and augment adaptive immune responses by promoting differentiation, activation, and/or recruitment of accessory immune cells to sites of malignancy. Nevertheless, integrated and coordinated mechanisms of subversion of NK cell activity against the tumor and its microenvironment exist. Although our understanding of the receptor ligand interactions that regulate NK cell functionality has evolved remarkably, the diversity of ligands and receptors is complex, as is their mechanistic foundations in regulating NK cell function. In this article, we review the literature and highlight how the TME manipulates the NK cell phenotypes, genotypes, and tropism to evade tumor recognition and elimination. We discuss counter strategies that may be adopted to augment the efficacy of NK cell anti-tumor surveillance, the clinical trials that have been undertaken so far in solid malignancies, critically weighing the challenges and opportunities with this approach.publishedVersio

    Assigning channels via the meet-in-the-middle approach

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    We study the complexity of the Channel Assignment problem. By applying the meet-in-the-middle approach we get an algorithm for the \ell-bounded Channel Assignment (when the edge weights are bounded by \ell) running in time O((2+1)n)O^*((2\sqrt{\ell+1})^n). This is the first algorithm which breaks the (O())n(O(\ell))^n barrier. We extend this algorithm to the counting variant, at the cost of slightly higher polynomial factor. A major open problem asks whether Channel Assignment admits a O(cn)O(c^n)-time algorithm, for a constant cc independent of \ell. We consider a similar question for Generalized T-Coloring, a CSP problem that generalizes \CA. We show that Generalized T-Coloring does not admit a 22o(n)poly(r)2^{2^{o\left(\sqrt{n}\right)}} {\rm poly}(r)-time algorithm, where rr is the size of the instance.Comment: SWAT 2014: 282-29

    On the Equivalence among Problems of Bounded Width

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    In this paper, we introduce a methodology, called decomposition-based reductions, for showing the equivalence among various problems of bounded-width. First, we show that the following are equivalent for any α>0\alpha > 0: * SAT can be solved in O(2αtw)O^*(2^{\alpha \mathrm{tw}}) time, * 3-SAT can be solved in O(2αtw)O^*(2^{\alpha \mathrm{tw}}) time, * Max 2-SAT can be solved in O(2αtw)O^*(2^{\alpha \mathrm{tw}}) time, * Independent Set can be solved in O(2αtw)O^*(2^{\alpha \mathrm{tw}}) time, and * Independent Set can be solved in O(2αcw)O^*(2^{\alpha \mathrm{cw}}) time, where tw and cw are the tree-width and clique-width of the instance, respectively. Then, we introduce a new parameterized complexity class EPNL, which includes Set Cover and Directed Hamiltonicity, and show that SAT, 3-SAT, Max 2-SAT, and Independent Set parameterized by path-width are EPNL-complete. This implies that if one of these EPNL-complete problems can be solved in O(ck)O^*(c^k) time, then any problem in EPNL can be solved in O(ck)O^*(c^k) time.Comment: accepted to ESA 201

    Crime in Maine 2014

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    Automata over infinite alphabets have recently come to be studied extensively as potentially useful tools for solving problems in verification and database theory. One popular model of automata studied is the Class Memory Automata (CMA), for which the emptiness problem is equivalent to Petri Net Reachability. We identify a restriction - which we call weakness - of CMA, and show that their emptiness problem is equivalent to Petri Net Coverability. Further, we show that in the deterministic case they are closed under all Boolean operations. We clarify the connections between weak CMA and existing automata over data languages. We also extend CMA to operate over multiple levels of nested data values, and show that while these have undecidable emptiness in general, adding the weakness constraint recovers decidability of emptiness, via reduction to coverability in well-structured transition systems. We also examine connections with existing automata over nested data.Comment: Preprint of LATA'15 pape
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