3,886 research outputs found

    The cost of surgical training: analysis of operative time for laparoscopic cholecystectomy

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    Background: Duration of surgery is a main cost factor of surgical training. The purpose of this analysis of operative times for laparoscopic cholecystectomies (LC) was to quantify the extra time and related costs in regards to the surgeons' experience in the operating room (OR). Methods: All LC performed between January 01, 2005 and December 31, 2008 in 46 hospitals reporting to the database of the Swiss Association for Quality Management in Surgery (AQC) were analyzed (n=10,010). Four levels of seniority were specified: resident (R), junior consultant (JC), senior consultant (SC), and attending surgeon (AS). The differences in operative time according to seniority were investigated in a multivariable log-linear and median regression analysis controlling for possible confounders. The OR costs were calculated by using a full cost rate in a teaching hospital. Results: A total of 9,208 LC were available for analysis; 802 had to be excluded due to missing data (n=212) or secondary major operations (n=590). Twenty-eight percent of the LC were performed by R as teaching operations (n=2,591). Compared with R, the multivariable analysis of operative time showed a median difference of −2.5min (−9.0; 4.8) for JC and −18min (−25; −11) for SC and −28min (−35; −10) for AS, respectively. The OR minute costs were €17.57, resulting in incremental costs of €492 (159; 615) per operation in case of tutorial assistance. Conclusions: The proportion of LC performed as tutorial assistance for R remains low. Surgical training in the OR causes relevant case-related extra time and therefore cost

    On Structural Parameterizations of Hitting Set: Hitting Paths in Graphs Using 2-SAT

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    Hitting Set is a classic problem in combinatorial optimization. Its input consists of a set system F over a finite universe U and an integer t; the question is whether there is a set of t elements that intersects every set in F. The Hitting Set problem parameterized by the size of the solution is a well-known W[2]-complete problem in parameterized complexity theory. In this paper we investigate the complexity of Hitting Set under various structural parameterizations of the input. Our starting point is the folklore result that Hitting Set is polynomial-time solvable if there is a tree T on vertex set U such that the sets in F induce connected subtrees of T. We consider the case that there is a treelike graph with vertex set U such that the sets in F induce connected subgraphs; the parameter of the problem is a measure of how treelike the graph is. Our main positive result is an algorithm that, given a graph G with cyclomatic number k, a collection P of simple paths in G, and an integer t, determines in time 2^{5k} (|G| +|P|)^O(1) whether there is a vertex set of size t that hits all paths in P. It is based on a connection to the 2-SAT problem in multiple valued logic. For other parameterizations we derive W[1]-hardness and para-NP-completeness results.Comment: Presented at the 41st International Workshop on Graph-Theoretic Concepts in Computer Science, WG 2015. (The statement of Lemma 4 was corrected in this update.

    The Labour Government, the Treasury and the £6 pay policy of July 1975

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    The 1974-79 Labour Government was elected in a climate of opinion that was fiercely opposed to government intervention in the wage determination process, and was committed to the principles of free collective bargaining in its manifestoes. However, by December 1974 the Treasury was advocating a formal incomes policy, and by July 1975 the government had introduced a £6 flat rate pay norm. With reference to archival sources, the paper demonstrates that TUC and Labour Party opposition to incomes policy was reconciled with the Treasury's advocacy by limiting the Bank of England‟s intervention in the foreign exchange market when sterling came under pressure. This both helped to achieve the Treasury's objective of improving the competitiveness of British industry, and acted as a catalyst for the introduction of incomes policy because the slide could be attributed to a lack of market confidence in British counter-inflation policy

    Characterization of biomass emissions and potential reduction insmall-scale pellet boiler

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    6noIn recent years it has been proved that residential biomass combustion has a direct influence on ambient air quality, especially in the case of cereals. The aim of this study is the characterization of the emissions in small-scale fixed-bed pellet boiler (heat output of 25 kW) of beech and corn, and of its potential reduction to an addition of calcium dihydroxide. In the biomass combustion test 7 fuel mixtures were investigated with regard to the particulate content (PM10), gaseous emissions and combustion chamber deposit. The corn kernels tanned with calcium dihydroxide determined a decrease in particulate emissions (54±13 mg MJ− 1) in comparison to corn, whereas in the combustion of corn pellet with 1% calcium dihydroxide high emissions were observed (193±21 mg MJ− 1). With regard to SO2 emissions, the combustion of corn with the additives make a reduction in comparison to additive-free corn.openopenDELL'ANTONIA D.;Pergher G;Cividino SRS;Gubiani R;Cecchini M;Marucci ADell'Antonia, D.; Pergher, G; Cividino, Srs; Gubiani, R; Cecchini, M; Marucci,

    Profiling of Glycan Receptors for Minute Virus of Mice in Permissive Cell Lines Towards Understanding the Mechanism of Cell Recognition

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    The recognition of sialic acids by two strains of minute virus of mice (MVM), MVMp (prototype) and MVMi (immunosuppressive), is an essential requirement for successful infection. To understand the potential for recognition of different modifications of sialic acid by MVM, three types of capsids, virus-like particles, wild type empty (no DNA) capsids, and DNA packaged virions, were screened on a sialylated glycan microarray (SGM). Both viruses demonstrated a preference for binding to 9-O-methylated sialic acid derivatives, while MVMp showed additional binding to 9-O-acetylated and 9-O-lactoylated sialic acid derivatives, indicating recognition differences. The glycans recognized contained a type-2 Galβ1-4GlcNAc motif (Neu5Acα2-3Galβ1-4GlcNAc or 3′SIA-LN) and were biantennary complex-type N-glycans with the exception of one. To correlate the recognition of the 3′SIA-LN glycan motif as well as the biantennary structures to their natural expression in cell lines permissive for MVMp, MVMi, or both strains, the N- and O-glycans, and polar glycolipids present in three cell lines used for in vitro studies, A9 fibroblasts, EL4 T lymphocytes, and the SV40 transformed NB324K cells, were analyzed by MALDI-TOF/TOF mass spectrometry. The cells showed an abundance of the sialylated glycan motifs recognized by the viruses in the SGM and previous glycan microarrays supporting their role in cellular recognition by MVM. Significantly, the NB324K showed fucosylation at the non-reducing end of their biantennary glycans, suggesting that recognition of these cells is possibly mediated by the Lewis X motif as in 3′SIA-LeX identified in a previous glycan microarray screen

    In Vitro Digestion of Chestnut and Quebracho Tannin Extracts : Antimicrobial Effect, Antioxidant Capacity and Cytomodulatory Activity in Swine Intestinal IPEC-J2 Cells

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    Quebracho (Qu) and chestnut (Ch) are natural sources of tannins and they are currently used in animal nutrition as feed ingredients. However, to date the bio-accessibility, antimicrobial, antioxidant, and intestinal epithelial cell stimulatory doses of Qu and Ch have not been determined. Our study investigates the antioxidant and E. coli F4+ and F18+ growth inhibitory activity of Qu, Ch, and their combinations after solubilization in water (to evaluate the already bio-accessible molecules) and after simulated gastro-intestinal digestion in vitro. The effect of an in vitro digested Ch and Qu combination was also tested on intestinal epithelial IPEC-J2 cells experimentally stressed with hydrogen peroxide (H2O2) and Dextran Sodium Sulfate (DSS). The results showed that undigested Qu and Ch alone, and in combination, exerted a valuable antioxidant capacity and E. coli F4+ and F18+ growth inhibitory activity. The concentration of 1200 \u3bcg/mL exhibited the highest E. coli growth inhibitory activity for all the samples tested. In addition, after in vitro digestion, Qu and Qu50%\u2013Ch50% maintained E. coli growth inhibitory activity and a modest antioxidant capacity. Three hours pre-treatment with in vitro digested Qu50%\u2013Ch50% counteracted the H2O2 and DSS experimentally-induced stress in the intestinal IPEC-J2 cells. Ch and Qu tannin extracts, particularly when combined, may exert E. coli F4+ and F18+ growth inhibitory activity and valuable antioxidant and cell viability modulation activities

    Exploring circannual rhythms and chronotype effect in patients with Obsessive-Compulsive Tic Disorder (OCTD) : a pilot study

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    Background: The aim of this study was to test, through a chronobiologic approach, the existence of a significant circannual rhythm of tics and obsessive-compulsive symptoms in patients with Obsessive-Compulsive Tic Disorder (OCTD). The chronotype effect on tics and OC symptoms during seasons was also studied. Methods: Patients with a diagnosis of OCTD (N = 37; mean age = 18.78 \ub1 8.61) underwent four clinical evaluations: Winter (WIN), Spring (SPR), Summer (SUM) and Autumn (AUT). Tics were evaluated through Yale Global Tic Severity Scale (YGTSS) and OC symptoms through Yale-Brown Obsessive Compulsive Scale (Y-BOCS). Patients\u2019 chronotype was assessed by the Horne-Ostberg morningness-eveningness questionnaire (MEQ), which categorizes subjects according to the individuals'chronotype, being morning-type, evening-type, and neither-type. Results: A statistically significant circannual rhythm was observed for OC symptoms (p = 0.007), with the acrophase occurring between AUT and WIN. Y-BOCS differed along the year (p = 0.0003 and \u3b72p = 0.40) with lower results in SUM compared to WIN (p < 0.05) and AUT (p < 0.01). Tics displayed no circannual rhythm and YGTSS scores were comparable among seasons. Patients were classified as 15 morning-types (40.5%) 15 neither-types (40.5%) and 7 evening-types (19.0%). YGTSS data were similar for all chronotypes while Y-BOCS results were greater during SUM in evening-types than morning-type patients (p < 0.05; 15.7 \ub1 5.2 vs 3.4 \ub1 6.0). Limitations: It is essential to investigate the existence of tics and OC symptoms circannual rhythms over the course of more than one year with a larger sample. Conclusions: OC symptoms displayed a significant circannual rhythm and were influenced by patients\u2019 chronotype. On the contrary, tics resulted similar among seasons and chronotypes

    Asymptotics for the number of eigenvalues of three-particle Schr\"{o}dinger operators on lattices

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    We consider the Hamiltonian of a system of three quantum mechanical particles (two identical fermions and boson)on the three-dimensional lattice Z3\Z^3 and interacting by means of zero-range attractive potentials. We describe the location and structure of the essential spectrum of the three-particle discrete Schr\"{o}dinger operator Hγ(K),H_{\gamma}(K), KK being the total quasi-momentum and γ>0\gamma>0 the ratio of the mass of fermion and boson. We choose for γ>0\gamma>0 the interaction v(γ)v(\gamma) in such a way the system consisting of one fermion and one boson has a zero energy resonance. We prove for any γ>0\gamma> 0 the existence infinitely many eigenvalues of the operator Hγ(0).H_{\gamma}(0). We establish for the number N(0,γ;z;)N(0,\gamma; z;) of eigenvalues lying below z<0z<0 the following asymptotics limz0N(0,γ;z)logz=U(γ). \lim_{z\to 0-}\frac{N(0,\gamma;z)}{\mid \log \mid z\mid \mid}={U} (\gamma) . Moreover, for all nonzero values of the quasi-momentum KT3K \in T^3 we establish the finiteness of the number N(K,γ;τess(K)) N(K,\gamma;\tau_{ess}(K)) of eigenvalues of H(K)H(K) below the bottom of the essential spectrum and we give an asymptotics for the number N(K,γ;0)N(K,\gamma;0) of eigenvalues below zero.Comment: 25 page
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