2,908 research outputs found

    Peripheral separability and cusps of arithmetic hyperbolic orbifolds

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    For X = R, C, or H it is well known that cusp cross-sections of finite volume X-hyperbolic (n+1)-orbifolds are flat n-orbifolds or almost flat orbifolds modelled on the (2n+1)-dimensional Heisenberg group N_{2n+1} or the (4n+3)-dimensional quaternionic Heisenberg group N_{4n+3}(H). We give a necessary and sufficient condition for such manifolds to be diffeomorphic to a cusp cross-section of an arithmetic X-hyperbolic (n+1)-orbifold. A principal tool in the proof of this classification theorem is a subgroup separability result which may be of independent interest.Comment: Published by Algebraic and Geometric Topology at http://www.maths.warwick.ac.uk/agt/AGTVol4/agt-4-32.abs.htm

    The Methods to Improve Quality of Service by Accounting Secure Parameters

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    A solution to the problem of ensuring quality of service, providing a greater number of services with higher efficiency taking into account network security is proposed. In this paper, experiments were conducted to analyze the effect of self-similarity and attacks on the quality of service parameters. Method of buffering and control of channel capacity and calculating of routing cost method in the network, which take into account the parameters of traffic multifractality and the probability of detecting attacks in telecommunications networks were proposed. The both proposed methods accounting the given restrictions on the delay time and the number of lost packets for every type quality of service traffic. During simulation the parameters of transmitted traffic (self-similarity, intensity) and the parameters of network (current channel load, node buffer size) were changed and the maximum allowable load of network was determined. The results of analysis show that occurrence of overload when transmitting traffic over a switched channel associated with multifractal traffic characteristics and presence of attack. It was shown that proposed methods can reduce the lost data and improve the efficiency of network resources.Comment: 10 pages, 1 figure, 1 equation, 1 table. arXiv admin note: text overlap with arXiv:1904.0520

    Neural connectivity biotypes: associations with internalizing problems throughout adolescence.

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    BackgroundNeurophysiological patterns may distinguish which youth are at risk for the well-documented increase in internalizing symptoms during adolescence. Adolescents with internalizing problems exhibit altered resting-state functional connectivity (RSFC) of brain regions involved in socio-affective processing. Whether connectivity-based biotypes differentiate adolescents' levels of internalizing problems remains unknown.MethodSixty-eight adolescents (37 females) reported on their internalizing problems at ages 14, 16, and 18 years. A resting-state functional neuroimaging scan was collected at age 16. Time-series data of 15 internalizing-relevant brain regions were entered into the Subgroup-Group Iterative Multi-Model Estimation program to identify subgroups based on RSFC maps. Associations between internalizing problems and connectivity-based biotypes were tested with regression analyses.ResultsTwo connectivity-based biotypes were found: a Diffusely-connected biotype (N = 46), with long-range fronto-parietal paths, and a Hyper-connected biotype (N = 22), with paths between subcortical and medial frontal areas (e.g. affective and default-mode network regions). Higher levels of past (age 14) internalizing problems predicted a greater likelihood of belonging to the Hyper-connected biotype at age 16. The Hyper-connected biotype showed higher levels of concurrent problems (age 16) and future (age 18) internalizing problems.ConclusionsDifferential patterns of RSFC among socio-affective brain regions were predicted by earlier internalizing problems and predicted future internalizing problems in adolescence. Measuring connectivity-based biotypes in adolescence may offer insight into which youth face an elevated risk for internalizing disorders during this critical developmental period

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    ABSTRACT Context Synchronous cystic neoplasms of pancreas are a highly rare occurrence. Case report We report a very rare case of coexistent serous cystadenoma and multi-side branch intraductal papillary mucinous neoplasm (IPMN). Conclusion To our knowledge, there has been only one previous case report in the literature of a synchronous serous cystadenoma and a solitary IPMN lesion. This case report is intended to increase the awareness of this condition while alluding to the need for diligent examination by endosonographers. It also highlights the clinical impact of endosonography on the diagnosis and management of cystic legions in the pancreas

    Status of research on control of fungal diseases of pearl millet

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    The paper reviews the research carried out during last 15 years on the control (Centered, biological and chemical control and utilization of host plant resistance) of fungal diseases (ergot, smut, downy mildew, rust) of pearl millet.

    Problem gambling: a suitable case for social work?

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    Problem gambling attracts little attention from health and social care agencies in the UK. Prevalence surveys suggest that 0.6% of the population are problem gamblers and it is suggested that for each of these individuals, 10–17 other people, including children and other family members, are affected. Problem gambling is linked to many individual and social problems including: depression, suicide, significant debt, bankruptcy, family conflict, domestic violence, neglect and maltreatment of children and offending. This makes the issue central to social work territory. Yet, the training of social workers in the UK has consistently neglected issues of addictive behaviour. Whilst some attention has been paid in recent years to substance abuse issues, there has remained a silence in relation to gambling problems. Social workers provide more help for problems relating to addictions than other helping professions. There is good evidence that treatment, and early intervention for gambling problems, including psycho-social and public health approaches, can be very effective. This paper argues that problem gambling should be moved onto the radar of the social work profession, via inclusion on qualifying and post-qualifying training programmes and via research and dissemination of good practice via institutions such as the Social Care Institute for Excellence (SCIE). Keywords: problem gambling; addictive behaviour; socia

    Assessment of metabolic changes in \u3ci\u3eMycobacterium smegmatis\u3c/i\u3e wild type and \u3ci\u3ealr\u3c/i\u3e mutant strains: evidence for a new pathway of D-alanine biosynthesis.

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    In mycobacteria, D-alanine is an essential precursor for peptidoglycan biosynthesis. The only confirmed enzymatic pathway to form D-alanine is through the racemization of L-alanine by alanine racemase (Alr, EC 5.1.1.1). Nevertheless, the essentiality of Alr in Mycobacterium tuberculosis and Mycobacterium smegmatis for cell survivability in the absence of D-alanine has been a point of controversy with contradictory results reported in the literature. To address this issue, we examined the effects of alr inactivation on the cellular metabolism of M. smegmatis. The M. smegmatis alr insertion mutant TAM23 exhibited essentially identical growth to wild type mc2155 in the absence of D-alanine. NMR metabolomics revealed drastically distinct phenotypes between mc2155 and TAM23. A metabolic switch was observed for TAM23 as a function of supplemented D-alanine. In the absence of D-alanine, the metabolic response directed carbon through an unidentified transaminase to provide the essential D-alanine required for survival. The process is reversed when D-alanine is available, in which the D-alanine is directed to peptidoglycan biosynthesis. Our results provide further support for the hypothesis that Alr is not an essential function of M. smegmatis, and that specific Alr inhibitors will have no bactericidal action

    Emerging debt and equity markets: an exploratory investigation of integration using daily data

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    In this paper we examine integration between emerging and U.S. debt and equity markets. We first investigate price changes around significant "events," in this case changes in short-term U.S. interest rates brought about by actions of the Federal Reserve. Second, we estimate the predictability of returns using both domestic and U.S. variables. Finally, we test whether a single latent variable can explain these returns. The evidence suggests that the degree of integration varies with security types and the country of origin. However, these differences between security types become less apparent over time.Financial markets ; International finance
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