3,781 research outputs found

    A nonabelian normal subgroup with a core-free projective image

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    Strong decays of radially excited vector mesons

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    Motivated by the recent discovery at Orsay of Ļ•ā€² (1680), we study the strong interaction decays of radially excited vector mesons within the framework of the3P0 quark pair creation model. We stress the relative importance of phase space, algebraic spinflavor couplings, and spatial overlaps. Quite a few features of the data can be will understood by the presence of a node in the spatial wave function, but the detailed structure of the modes Ļā€²ā†’4Ļ€ remains a serious challenge

    Effect of metabolic and antioxidant supplementation on sperm parameters in oligo-astheno-teratozoospermia, with and without varicocele: a double-blind placebo-controlled study

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    Since sperm require high energy levels to perform their specialised function, it is vital that essential nutrients are available for spermatozoa when they develop, capacitate and acquire motility. However, they are vulnerable to a lack of energy and excess amounts of reactive oxygen species, which can impair sperm function, lead to immotility, acrosomal reaction impairment, DNA fragmentation and cell death. This monocentric, randomised, double-blind, placebo-controlled trial investigated the effect of 6 months of supplementation with l-carnitine, acetyl-l-carnitine and other micronutrients on sperm quality in 104 subjects with oligo- and/or astheno- and/or teratozoospermia with or without varicocele. In 94 patients who completed the study, sperm concentration was significantly increased in supplemented patients compared to the placebo (p =.0186). Total sperm count also increased significantly (p =.0117) in the supplemented group as compared to the placebo group. Both, progressive and total motility were higher in supplemented patients (p =.0088 and p =.0120, respectively). Although pregnancy rate was not an endpoint of the study, of the 12 pregnancies that occurred during the follow-up, 10 were reported in the supplementation group. In general, all these changes were more evident in varicocele patients. In conclusion, supplementation with metabolic and antioxidant compounds could be efficacious when included in strategies to improve fertility

    Kalai and Muller's Possibility Theorem: A Simplified Integer Programming Version

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    We provide a respecification of an integer programming characterization of Arrovian social welfare functions introduced by Sethuraman et al. (Math Oper Res 28:309ā€“326, 2003). By exploiting this respecification, we give a new and simpler proof of Theorem 2 in Kalai and Muller (J Econ Theory 16:457ā€“469, 1977)

    On the foundation of monopoly in bilateral exchange

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    We address the problem of monopoly in general equilibrium in a mixed version of a monopolistic two-commodity exchange economy where the monopolist, represented as an atom, is endowed with one commodity and ā€œsmall traders,ā€ represented by an atomless part, are endowed only with the other. First we provide an economic theoretical foundation of the monopoly solution in this bilateral framework through a formalization of an explicit trading process inspired by Pareto (Cours dā€™Ć©conomie politique. F. Rouge Editeur, Lausanne, 1896) for an exchange economy with a finite number of commodities, and we give the conditions under which our monopoly solution has the geometric characterization proposed by Schydlowsky and Siamwalla (Q J Econ 80:147ā€“153, 1966). Then, we provide a game theoretical foundation of our monopoly solution through a two-stage reformulation of our model. This allows us to prove that the set of the allocations corresponding to a monopoly equilibrium and the set of the allocations corresponding to a subgame perfect equilibrium of the two-stage game coincide. Finally, we compare our model of monopoly with a bilateral exchange version of a pioneering model proposed by Forchheimer (Jahrbuch fĆ¼r Gesetzgebung, Verwaltung und Volkswirschafts im Deutschen Reich 32:1ā€“12, 1908), known as a model of ā€œpartial monopolyā€ since there a monopolist shares a market with aā€œcompetitive fringe.ā€ Journal of Economic Literature Classification Numbers: D42, D51

    Chronic bacterial prostatitis: efficacy of short-lasting antibiotic therapy with prulifloxacin (UnidroxĀ®) in association with saw palmetto extract, lactobacillus sporogens and arbutin (LactorepensĀ®)

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    Bacterial prostatitis (BP) is a common condition accounting responsible for about 5-10% of all prostatitis cases; chronic bacterial prostatitis (CBP) classified as type II, are less common but is a condition that significantly hampers the quality of life, (QoL) because not only is it a physical condition but also a psychological distress. Commonly patients are treated with antibiotics alone, and in particular fluoroquinolones are suggested by the European Urology guidelines. This approach, although recommended, may not be enough. Thus, a multimodal approach to the prolonged antibiotic therapy may be helpful.210 patients affected by chronic bacterial prostatitis were enrolled in the study. All patients were positive to Meares-Stamey test and symptoms duration wasā€‰>ā€‰3 months. The purpose of the study was to evaluate the efficacy of a long lasting therapy with a fluoroquinolone in association with a nutraceutical supplement (prulifloxacin 600 mg for 21 days and an association of Serenoa repens 320 mg, Lactobacillus Sporogens 200 mg, Arbutin 100 mg for 30 days). Patients were randomized in two groups (A and B) receiving respectively antibiotic alone and an association of antibiotic plus supplement.Biological recurrence at 2 months in Group A was observed in 21 patients (27.6%) and in Group B in 6 patients (7.8%). Uropathogens found at the first follow-up were for the majority Gram - (E. coli and Enterobacter spp.). A statistically significant difference was found at the time of the follow-up between Group A and B in the NIH-CPSI questionnaire score, symptoms evidence and serum PSA.Broad band, short-lasting antibiotic therapy in association with a nutritional supplement (serenoa repens, lactobacillus sporogens and arbutin) show better control and recurrence rate on patients affected by chronic bacterial prostatitits in comparison with antibiotic treatment alone.NCT02130713Date of trial Registration: 30/04/2014

    European Guidelines for Obesity Management in Adults with a Very Low-Calorie Ketogenic Diet: A Systematic Review and Meta-Analysis

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    Background: The very low-calorie ketogenic diet (VLCKD) has been recently proposed as an appealing nutritional strategy for obesity management. The VLCKD is characterized by a low carbohydrate content (<50 g/day), 1-1.5 g of protein/kg of ideal body weight, 15-30 g of fat/day, and a daily intake of about 500-800 calories. Objectives: The aim of the current document is to suggest a common protocol for VLCKD and to summarize the existing literature on its efficacy in weight management and weight-related comorbidities, as well as the possible side effects. Methods: This document has been prepared in adherence with Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines. Literature searches, study selection, methodology development, and quality appraisal were performed independently by 2 authors and the data were collated by means of a meta-analysis and narrative synthesis. Results: Of the 645 articles retrieved, 15 studies met the inclusion criteria and were reviewed, revealing 4 main findings. First, the VLCKD was shown to result in a significant weight loss in the short, intermediate, and long terms and improvement in body composition parameters as well as glycemic and lipid profiles. Second, when compared with other weight loss interventions of the same duration, the VLCKD showed a major effect on reduction of body weight, fat mass, waist circumference, total cholesterol and triglyceridemia as well as improved insulin resistance. Third, although the VLCKD also resulted in a significant reduction of glycemia, HbA1c, and LDL cholesterol, these changes were similar to those obtained with other weight loss interventions. Finally, the VLCKD can be considered a safe nutritional approach under a health professional's supervision since the most common side effects are usually clinically mild and easily to manage and recovery is often spontaneous. Conclusions: The VLCKD can be recommended as an effective dietary treatment for individuals with obesity after considering potential contra-indications and keeping in mind that any dietary treatment has to be personalized. Prospero Registry: The assessment of the efficacy of VLCKD on body weight, body composition, glycemic and lipid parameters in overweight and obese subjects: a meta-analysis (CRD42020205189)

    Stereochemistry of the insertion of disubstituted alkynes into the metal aminocarbyne bond in diiron complexes

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    Terminal alkynes (HCdropCR') (R'=COOMe, CH2OH) insert into the metal-carbyne bond of the diiron complexes [Fe-2{mu-CN(Me)(R)} (mu-CO)(CO)(NCMe)(Cp)(2)][SO3CF3] (R=Xyl, 1a; CH2Ph, 1b; Me, 1c; Xyl=2,6-Me2C6H3), affording the corresponding mu-vinyliminium complexes [Fe-2{mu-sigma:eta(3)-C(R')=CHC=N(Me)(R)}(mu-CO)(CO)(Cp)(2)][SO3CF3] (R=Xyl, R'=COOMe, 2; R=CH2Ph, R'=COOMe, 3; R=Me, R'=COOMe, 4; R=Xyl, R'=CH2OH, 5; R=Me, R'=CH2OH, 6). The insertion is regiospecific and C-C bond formation selectively occurs between the carbyne carbon and the CH moiety of the alkyne. Disubstituted alkynes (R'CdropCR') also insert into the metal-carbyne bond leading to the formation of [Fe-2{mu-sigma:eta(3)- C(R')=C(R')C=N(Me)(R)}(mu-CO)(CO)(Cp)(2)][SO3CF3] (R'=Me, R=Xyl, 8; R'=Et, R=Xyl, 9; R'=COOMe, R=Xyl, 10; R'=COOMe, R=CH2Ph, 11; R'= COOMe, R=Me, 12). Complexes 2, 3, 5, 8, 9 and 11, in which the iminium nitrogen is unsymmetrically substituted, give rise to E and/or Z isomers. When iminium substituents are Me and Xyl, the NMR and structural investigations (X-ray structure analysis of 2 and 8) indicate that complexes obtained from terminal alkynes preferentially adopt the E configuration, whereas those derived from internal alkynes are exclusively Z. In complexes 8 and 9, trans and cis isomers have been observed, by NMR spectroscopy, and the structures of trans-8 and cis-8 have been determined by X-ray diffraction studies. Trans to cis isomerization occurs upon heating in THF at reflux temperature. In contrast to the case of HCdropCR', the insertion of 2-hexyne is not regiospecific: both [Fe-2{mu-sigma:eta(3)-C(CH2CH2CH3)=C(Me)C=N(Me)(R)} (mu-CO)(CO)(Cp)(2)][SO3CF3] (R=Xyl, 13; R=Me, 15) and [Fe-2{mu-sigma:eta(3)-C(Me)=C(CH2CH2CH3)C=N(Me)(R)}(mu-CO)(CO)(Cp)(2)][SO3CF3] (R=Xyl, 14, R=Me, 16) are obtained and these compounds are present in solution as a mixture of cis and trans isomers, with predominance of the former

    Hydride addition at m-vinyliminium ligand obtained from disubstituted alkynes

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    New Ī¼-vinylalkylidene complexes cis-[Fe2{Ī¼-Ī·1:Ī·3-CĪ³(Rā€²)CĪ²(Rā€³)CĪ±HN(Me)(R)}(Ī¼-CO)(CO)(Cp)2] (R = Me, Rā€² = Rā€³ = Me, 3a; R = Me, Rā€² = Rā€³ = Et, 3b; R = Me, Rā€² = Rā€³ = Ph, 3c; R = CH2Ph, Rā€² = Rā€³ = Me, 3d; R = CH2Ph, Rā€² = Rā€³ = COOMe, 3e; R = CH2 Ph, Rā€² = SiMe3, Rā€³ = Me, 3f) have been obtained b yreacting the corresponding vinyliminium complexes [Fe2{Ī¼-Ī·1:Ī·3-CĪ³(Rā€²)CĪ²(Rā€³)CĪ±N(Me)(R)}(Ī¼-CO)(CO)(Cp)2][SO3CF3] (2aā€“f) with NaBH4. The formation of 3aā€“f occurs via selective hydride addition at the iminium carbon (CĪ±) of the precursors 2aā€“f. By contrast, the vinyliminiumcis-[Fe2{Ī¼-Ī·1:Ī·3-CĪ³ (Rā€²) = CĪ²(Rā€³)CĪ± = N(Me)(Xyl)}(Ī¼-CO)(CO)(Cp)2][SO3CF3] (Rā€² = Rā€³ = COOMe, 4a; Rā€² = Rā€³ = Me, 4b; Rā€² = Prn, Rā€³ = Me, 4c; Prn = CH2CH2CH3, Xyl = 2,6-Me2C6H3) undergo Hāˆ’ addition at the adjacent CĪ², affording the bis-alkylidene complexes cis-[Fe2{Ī¼-Ī·1:Ī·2-C(Rā€²)C(H)(Rā€³)CN(Me)(Xyl)}(Ī¼-CO)(CO)(Cp)2], (5aā€“c). The cis and trans isomers of [Fe2{Ī¼-Ī·1:Ī·3-CĪ³(Et)CĪ²(Et)CĪ±N(Me)(Xyl)}(Ī¼-CO)(CO)(Cp)2][SO3CF3] (4d) react differently with NaBH4: the former reacts at CĪ± yielding cis-[Fe2{Ī¼-Ī·1:Ī·3-CĪ³(Et)CĪ²(Et)CĪ±HN(Me)(Xyl)}(Ī¼-CO)(CO)(Cp)2], 6a, whereas the hydride attack occurs at CĪ² of the latter, leading to the formation of the bis alkylidene trans-[Fe2{Ī¼-Ī·1:Ī·2-C(Et)C(H)(Et)CN(Me)(Xyl)}(Ī¼-CO)(CO)(Cp)2] (5d). The structure of 5d has been determined by an X-ray diffraction study. Other Ī¼-vinylalkylidene complexes cis-[Fe2{Ī¼-Ī·1:Ī·3-CĪ³(Rā€²)CĪ²(Rā€³)CĪ±HN(Me)(Xyl)}(Ī¼-CO)(CO)(Cp)2], (Rā€² = Rā€³ = Ph, 6b; Rā€² = Rā€³ = Me, 6c) have been prepared, and the structure of 6c has been determined by X-ray diffraction. Compound 6b results from treatment of cis-[Fe2{Ī¼-Ī·1:Ī·3-CĪ³(Ph)CĪ²(Ph)CĪ±N(Me)(Xyl)}(Ī¼-CO)(CO)(Cp)2][SO3CF3] (4e) with NaBH4, whereas 6c has been obtained by reacting 4b with LiHBEt3. Both cis-4d and trans-4d react with LiHBEt3 affording cis-6a
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