997 resultados para Abelian groups.


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This paper contributes to the literature on centrality measures in economics by defining a team game and identifying the key players and key groups<br/>in the game. We extend the work of Ballester et al. (Econometrica, 2006) by incorporating a network outcome component in the players' payoff functions and prove that there is a unique interior Nash Equilibrium in pure strategies. We develop a team intercentrality measure based on alternative scenarios that capture the externality created by teammates on each player.

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This paper investigates a series of dendrons based on the Newkome dendritic scaffold that displays a naturally occurring polyamine (spermine) on their surface. These dendrons have previously been shown to interact with DNA in a generation dependent manner with the more highly branched dendrons exhibiting a strong multivalency effect for the spermine surface groups. In this paper, we investigate the ability of these dendrons to transfect DNA into cells (human breast carcinoma cells, MDA-MB-231, and murine myoblast cells, C2C12) as determined by the luciferase assay. Although the dendrons are unable to transfect DNA in their own right, they are capable of delivering DNA in vitro when administered with chloroquine, which assists with escape from endocytic vesicles. The cytotoxicity of the dendrons was determined using the XTT assay, and it was shown that the dendrons were nontoxic either alone or in the presence of DNA. However, when administered with DNA and chloroquine, the most highly branched dendron did exhibit some cytotoxicity. This paper elucidates the relationship between in vitro transfection efficiency and toxicity. While transfection efficiencies are modest, the low toxicity of the dendrons, both in their own right, and in the presence of DNA, provides encouragement that this type of building block, which has a relatively high affinity for DNA, will provide a useful starting point for the further synthetic development of more effective gene transfection agents.

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The motor points of the skeletal muscles, mainly of interest to anatomists and physiologists, have recently attracted much attention from researchers in the field of functional electrical stimulation. The muscle motor point has been defined as the entry point of the motor nerve branch into the epimysium of the muscle belly. Anatomists have pointed out that many muscles in the limbs have multiple motor points. Knowledge of the location of nerve branches and terminal nerve entry points facilitates the exact insertion and the suitable selection of the number of electrodes required for each muscle for functional electrical stimulation. The present work therefore aimed to describe the number, location, and distribution of motor points in the human forearm muscles to obtain optimal hand function in many clinical situations. Twenty three adult human cadaveric forearms were dissected. The numbers of primary nerves and motor points for each muscle were tabulated. The mean numbers and the standard deviation were calculated and grouped in tables. Data analyses were performed with the use of a statistical analysis package (SPSS 13.0). The proximal third of the muscle was the usual part of the muscle that received the motor points. Most of the forearm muscles were innervated from the lateral side and deep surface of the muscle. The information in this study may also be usefully applied in selective denervation procedures to balance muscles in spastic upper limbs. Copyright © 2007 Via Medica.

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This case describes a qualitative social science research project that was conducted in 2009 and that examined the experiences of recent migrants to Northern Ireland. While background to the research and key findings are presented, the topic forms a backdrop to the case. The following aspects of the study are presented: the theoretical context; formulating the research question, design and methodology; key methodological issues; data collection and analysis; project dissemination; and research funding and reporting. The case pays particular attention to the needs and impact of different groups including the researcher, the funding body, the researcher’s employer and the researched. The significance of access, language and ethics to this study are examined. Finally, the way in which the research unfolded in an often-unpredictable way throughout the implementation process is highlighted in the narrative.

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We express various sets of quantum correlations studied in the theoretical physics literature in terms of different tensor products of operator systems of discrete groups. We thus recover earlier results of Tsirelson and formulate a new approach for the study of quantum correlations. To do this we formulate a general framework for the study of operator systems arising from discrete groups. We study in detail the operator system of the free group Fn on n generators, as well as the operator systems of the free products of finitely many copies of the two-element group Z2. We examine various tensor products of group operator systems, including the minimal, the maximal, and the commuting tensor products. We introduce a new tensor product in the category of operator systems and formulate necessary and sufficient conditions for its equality to the commuting tensor product in the case of group operator systems.

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We initiate the study of sets of p-multiplicity in locally compact groups and their operator versions. We show that a closed subset E of a second countable locally compact group G is a set of p-multiplicity if and only if E∗={(s,t):ts−1∈E} is a set of operator p-multiplicity. We exhibit examples of sets of p-multiplicity, establish preservation properties for unions and direct products, and prove a p-version of the Stone–von Neumann Theorem.

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The invention provides ionic liqs., [R'1CH(OH)CH2]NR'nX (X = anion, R' = alkyl, alkenyl, alkynyl, cycloalkyl, alkylcarbonylalkyl, alkoxy, haloalkyl, haloalkoxy, alkenyloxy, alkynyloxy, cycloalkyloxy, aryl), having a secondary hydroxyl group, and an atom-efficient method for the prepn. of these ionic liqs., by epoxidn. of a protonated nitrogen- contg. org. base (which can optionally be prepd. in situ) in the presence of an anion suitable for supporting ionic liq. formation. Thus, reaction of 1-methylimidazole with HCl in EtOH ∼ 25° followed by treatment with propylene oxide gave 1-(2-hydroxypropyl)-3-methylimidazolium chloride. [on SciFinder(R)]

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Photooxidative damage was induced predominantly at a single guanine base in a target DNA by irradiation (lambda > 330 nm) in the presence of complementary oligodeoxynucleotide conjugates (ODN-5'-linker-[Ru(phen)3]2+) (phen = 1,10-phenanthroline). The target DNA represents the b2a2 variant of the chimeric bcr-abl gene implicated in the pathogenesis of chronic myeloid leukaemia, and the sequence of the 17mer ODN component of the conjugate (3' G G T A G T T A T T C C T T C T T 5') was complementary to the junction region of the sense strand sequence of this oncogene. Two different conjugates were prepared, both of them by reaction of the appropriate succinimide ester with 5'-hexylamino-derivatised 17mer ODN. In Ru-ODN-1 (7) the linker was -(CH2)6-NHCO-bpyMe (-bpyMe = 4'-[4-methyl-2,2'-bipyridyl]), whereas in Ru-ODN-2 (13) it was -(CH2)6-NHCO-(CH2)3-CONH-phen. Photoexcitation of either of the conjugates when hybridised with the 32P-5'-end-labelled target 34mer 5'T G A C C A T C A A T A A G G A A G A A G21 C C C T T C A G C G G C C 3' (ODN binding site underlined) led to an alkali-labile site predominantly (> 90%) at the G21 base, which is at the junction of double-stranded and single-stranded regions of the hybrid. Greater yields were found with Ru-ODN-1 (7) than with Ru ODN-2 (13). In contrast to this specific cleavage with Ru-ODN-1 (7) or Ru-ODN-2 (13), alkali-labile sites were generated at all guanines when the 34mer was photolysed in the presence of the free sensitiser [Ru(phen)3]2+. Since [Ru(phen)3]2+ was shown to react with 2'-deoxyguanosine to form the diastereomers of a spiroiminodihydantoin derivative (the product from 1O2 reaction), 1O2 might also be an oxidizing species in the case of Ru-ODN-1 (7) and Ru-ODN-2 (13). Therefore to determine the range of reaction, a series of 'variant' targets was prepared, in which G21 was replaced with a cytosine and a guanine substituted for a base further towards the 3'-end (e.g. Variant 3; 5'T G A C C A T C A A T A A G G A A G A A C C G23 C T T C A G C G G32 C C3'). While it was noted that efficient reaction took place at distances apparently remote from the photosensitiser (e.g at G32, but not G23 for Variant 3), this effect could be attributed to hairpinning of the single-stranded region of the target. These results are therefore consistent with the photooxidative damage being induced by a reaction close to the photosensitiser rather than by a diffusible species such as 1O2.