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Significant Extension (significant + extension)
Selected AbstractsIncreasing longevity through caloric restriction or rapamycin feeding in mammals: common mechanisms for common outcomes?AGING CELL, Issue 5 2009Lynne S. Cox Summary Significant extension of lifespan in important mammalian species is bound to attract the attention not only of the aging research community, but also the media and the wider public. Two recent papers published by Harrison et al. (2009) in Nature and by Colman et al. (2009) in Science report increased longevity of mice fed with rapamycin and of rhesus monkeys undergoing caloric restriction, respectively. These papers have generated considerable debate in the aging community. Here we assess what is new about these findings, how they fit with our knowledge of lifespan extension from other studies and what prospects this new work holds out for improvements in human longevity and human health span. [source] Enhancement of haemostatic efficacy of plasma-derived FVIII by formulation with PEGylated liposomesHAEMOPHILIA, Issue 5 2009I. DAYAN Summary., We have shown previously that PEGylated liposomes (PEGLip) bind recombinant FVIII (rFVIII) with high affinity and specificity. This binding resulted in a significant extension of the biological activity of rFVIII as demonstrated in animal models and in clinical trials. In the present study we found that PEGLip bind plasma-derived factor VIII (pdFVIII). PEGLip binding did not affect potency or stability in vitro and did not alter levels of FVIII activity in vivo immediately after injection. However, formulation of pdFVIII with PEGLip led to several important improvements. Twenty-four and 30 hours after injection, FVIII activity levels were significantly higher in haemophilic mice injected with PEGLip-pdFVIII than in mice injected with standard pdFVIII. Half life, area under the curve and mean residence time were increased while clearance was decreased. In vivo efficacy was evaluated in a tail vein transection assay performed in haemophilic mice. Prophylactic treatment with PEGLip-pdFVIII was much more effective in prolonging survival in this assay than similar treatment with standard pdFVIII. These results suggest that formulation of pdFVIII with PEGLip has the potential to improve patient care by prolonging the biological efficacy of pdFVIII and reducing the frequency of FVIII infusions. [source] Fairness , up to a point.HUMAN RESOURCE MANAGEMENT JOURNAL, Issue 4 2006Assessing the impact of New Labour's employment legislation Since 1997 there has been a significant extension in the legal regulation of the employment relationship reflecting social and economic policy objectives. This article summarises key findings from research into the impact of this legislation and identifies factors affecting legislative impact and employer compliance. Tensions and priorities in the pursuit of the twin policy objectives are discussed. [source] Efficient generation of Heisenberg Hamiltonian matrices for VB calculations of potential energy surfacesINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 3 2009A. M. Tokmachev Abstract The spin-Hamiltonian valence bond theory relies upon covalent configurations formed by singly occupied orbitals differing by their spin counterparts. This theory has been proven to be successful in studying potential energy surfaces of the ground and lowest excited states in organic molecules when used as a part of the hybrid molecular mechanics,valence bond method. The method allows one to consider systems with large active spaces formed by n electrons in n orbitals and relies upon a specially proposed graphical unitary group approach. At the same time, the restriction of the equality of the numbers of electrons and orbitals in the active space is too severe: it excludes from the consideration a lot of interesting applications. We can mention here carbocations and systems with heteroatoms. Moreover, the structure of the method makes it difficult to study charge-transfer excited states because they are formed by ionic configurations. In the present work we tackle these problems by significant extension of the spin-Hamiltonian approach. We consider (i) more general active space formed by n ± m electrons in n orbitals and (ii) states with the charge transfer. The main problem addressed is the generation of Hamiltonian matrices for these general cases. We propose a scheme combining operators of electron exchange and hopping, generating all nonzero matrix elements step-by-step. This scheme provides a very efficient way to generate the Hamiltonians, thus extending the applicability of spin-Hamiltonian valence bond theory. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009 [source] The return of the political in social workINTERNATIONAL JOURNAL OF SOCIAL WELFARE, Issue 1 2009Mel Gray This article is a follow-up to our article ,Revisiting social work as art' and in part a response to Karen Healy's reply [both published in IJSW 17(2)]. It is, however, also a significant extension of this material since it engages with more general concerns about the critical project that is intrinsic to social work. Social work is not just about self-foundation based on knowledge, values and skills formation, but also about self-assertion. Crucially, it is through this notion of self-assertion that social work can be best understood as an agent of change. This transformative aspect of social work is our central focus. We are not concerned with structural conditions of power and domination but with theorising what a transformative politics would look like for social work using the lens of the French political philosopher Alain Badiou as a conceptual medium for permitting the return of the political for social work. [source] Effects of dietary restriction on mortality and age-related phenotypes in the short-lived fish Nothobranchius furzeriAGING CELL, Issue 2 2009Eva Terzibasi Summary The short-lived annual fish Nothobranchius furzeri shows extremely short captive life span and accelerated expression of age markers, making it an interesting model system to investigate the effects of experimental manipulations on longevity and age-related pathologies. Here, we tested the effects of dietary restriction (DR) on mortality and age-related markers in N. furzeri. DR was induced by every other day feeding and the treatment was performed both in an inbred laboratory line and a longer-lived wild-derived line. In the inbred laboratory line, DR reduced age-related risk and prolonged maximum life span. In the wild-derived line, DR induced early mortality, did not reduce general age-related risk and caused a small but significant extension of maximum life span. Analysis of age-dependent mortality revealed that DR reduced demographic rate of aging, but increased baseline mortality in the wild-derived strain. In both inbred- and wild-derived lines, DR prevented the expression of the age markers lipofuscin in the liver and Fluoro-Jade B (neurodegeneration) in the brain. DR also improved performance in a learning test based on conditioning (active avoidance in a shuttle box). Finally, DR induced a paradoxical up-regulation of glial fibrillary acidic protein in the brain. [source] Expanding the Criteria of Organ Procurement from Donors with Prostate Cancer: The Application of the New Italian GuidelinesAMERICAN JOURNAL OF TRANSPLANTATION, Issue 8 2010A. D'Errico-Grigioni Prostate cancer (CaP) represents the most prevalent malignancy in men more than 60-year-old, posing a problem in organ procurement from elderly subjects. However, most of the currently diagnosed CaP are low-grade and intraprostatic, with low metastatic risk, and there is recent evidence that most patients are overdiagnosed. The Italian National guidelines about organ acceptance from neoplastic donors changed in March 2005, extending the pool of potential candidates with CaP and introducing the function of a second opinion expert. Between 2001 and February 2005, 40 candidate donors with total PSA,10 and/or positive digital rectal examination underwent histopathological analysis of the prostate: 15 (37.5%) donors harboured CaP, and 25 (62%) were judged at ,standard risk'. After the introduction of the new guidelines in 2005, the second opinion expert judged at ,standard risk' 48 of 65 donors, while 17 of 65 needed histopathological analysis. Four (6.2%) donors harboured CaP, and 61 (94%) where judged at ,standard risk', with a significant increase of donated and actually transplanted organs. The application of the new guidelines and the introduction of a second opinion expert allowed a significant extension of the ,standard risk' category also to CaP patients, decreasing the histopathological examinations and expanding the donor pool. [source] A new class of models for bivariate joint tailsJOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES B (STATISTICAL METHODOLOGY), Issue 1 2009Alexandra Ramos Summary., A fundamental issue in applied multivariate extreme value analysis is modelling dependence within joint tail regions. The primary focus of this work is to extend the classical pseudopolar treatment of multivariate extremes to develop an asymptotically motivated representation of extremal dependence that also encompasses asymptotic independence. Starting with the usual mild bivariate regular variation assumptions that underpin the coefficient of tail dependence as a measure of extremal dependence, our main result is a characterization of the limiting structure of the joint survivor function in terms of an essentially arbitrary non-negative measure that must satisfy some mild constraints. We then construct parametric models from this new class and study in detail one example that accommodates asymptotic dependence, asymptotic independence and asymmetry within a straightforward parsimonious parameterization. We provide a fast simulation algorithm for this example and detail likelihood-based inference including tests for asymptotic dependence and symmetry which are useful for submodel selection. We illustrate this model by application to both simulated and real data. In contrast with the classical multivariate extreme value approach, which concentrates on the limiting distribution of normalized componentwise maxima, our framework focuses directly on the structure of the limiting joint survivor function and provides significant extensions of both the theoretical and the practical tools that are available for joint tail modelling. [source] Henry George and Classical Growth Theory: A Significant Contribution to Modeling Scale EconomiesAMERICAN JOURNAL OF ECONOMICS AND SOCIOLOGY, Issue 1 2001John Whitaker It is widely recognized that the analysis of economic growth in Henry George's Progress and Poverty was considerably influenced by the British classical tradition, especially the writings of Adam Smith, David Ricardo, and John Stuart Mill. What has been less clearly perceived is that George made significant extensions to the classical theory. This paper's aim is to provide an interpretation, and to some extent a "rational reconstruction," of George's positive analysis, largely leaving aside the striking normative lessons he drew from it. George's unsatisfactory treatment of capital is disposed of in Section I, while Section II,the core of the paper,follows George's lead in aggregating capital and labor into a single productive factor which is employed in a given natural environment. Section III adds the complication of improvement in the arts of production, and Section IV deals briefly with George's views on land speculation. Section V assesses, comparing George with his contemporary Alfred Marshall. [source] | |||||||||||||