10 resultados para Local basin of attraction

em Aston University Research Archive


Relevância:

100.00% 100.00%

Publicador:

Resumo:

The study examines the contribution of the Greens to the changing nature of West Germany's local politics in the 1980s. The changes correspond broadly to the politicisation and parliamentarisation of a sphere of government traditionally perceived as being "unpolitical". Building upon theories of the New Politics, it is suggested that the varying pace of socio-economic change across the Federal Republic underlies the nonuniform development of its local party systems. The party systems of localities which have witnessed rapid social and economic change are found to be more susceptible to the emergence of a New Politics dimension than those of communities in which change has occurred less rapidly. The thesis continues by addressing aspects of the Greens' role in the development of local party systems across the Federal Republic. Despite the fact that marked differences in the Greens' approach to local political participation are registered in communities of varying socio-economic types, it is argued that the Greens are largely responsible for the introduction of a "New Local Politics" dimension into West Germany's local party systems. In a comprehensive study of the Greens' role in the Mainz party system, the conflicting styles and practices of the Greens and the established political parties in the city are depicted. The failure of the Green Party to form an alliance with the SPD in the city council is attributed to the cleavage between the Greens' New Politics and the SPD's Old Politics approaches. A detailed analysis of the parliamentary initiatives introduced by the four parties represented in the Mainz council between 1984 and 1987 also supports the contention that a New Politics dimension exists in the city's party system. This dimension is identified as representing a significant source of conflict during the period of analysis.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This thesis describes the stratigraphy, sedimentology and diagenesis of the Pendleside Limestone (Asbian age), a sequence of limestones, shales and dolostones in the Clitheroe area of N. W. England. Field study of 19 measured sections indicates that it was deposited in a rhythmically subsiding basin (Craven Basin) because of movements on the Mid-Craven Fault which was active in Dinantian times. The sequence is up to 190m thick and consists mostly of distal turbidite deposits which have been reworked at horizons when sediment accumulation built up to the wave base. The original depositional fabric and mineralogy of the Pendleside Limestone Group has been extensively modified by diagenetic processes including cementation, authi­genesis, dolomitization and silicification. These processes have been studied using a wide variety of laboratory techniques. The carbonate cements of the PendIeside Limestone consist predominantly of ferroan calcite and non-ferroan calcite with microdolomite incIusions. The former is probably a stable replacement of original-high-magnesian calcite. Cementation was accompanied by the formation of authigenic albite and quartz. Much of the upper part of the Pendleside Limestone has been extensively dolomitized and chertified. Several distinct zones of dolomitization are found which increase in thickness and intensity towards the top of the Pendleside Limestone Group. The dolostone horizons correspond to coarser-grained lithologies deposited during periods of shallow water sedimentation. The composition of the dolomites changes from ferroan dolomite in the lower part of the Group to non-ferroan dolomite in the upper part. The low strontium and sodium content of the dolostones in association with the other evidence suggests that the dolomitization was brought about in an open system by the mixing of marine and fresh water in phreatic lens which were established at periodic intervals. The dolomitization was closely associated with chertification although this was initiated by the dissolution of siliceous spicules which provided the necessary source of silica.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Rare-earth co-doping in inorganic materials has a long-held tradition of facilitating highly desirable optoelectronic properties for their application to the laser industry. This study concentrates specifically on rare-earth phosphate glasses, (R2O3)x(R'2O3)y(P2O5)1-(x+y), where (R, R') denotes (Ce, Er) or (La, Nd) co-doping and the total rare-earth composition corresponds to a range between metaphosphate, RP3O9, and ultraphosphate, RP5O14. Thereupon, the effects of rare-earth co-doping on the local structure are assessed at the atomic level. Pair-distribution function analysis of high-energy X-ray diffraction data (Qmax = 28 Å-1) is employed to make this assessment. Results reveal a stark structural invariance to rare-earth co-doping which bears testament to the open-framework and rigid nature of these glasses. A range of desirable attributes of these glasses unfold from this finding; in particular, a structural simplicity that will enable facile molecular engineering of rare-earth phosphate glasses with 'dial-up' lasing properties. When considered together with other factors, this finding also demonstrates additional prospects for these co-doped rare-earth phosphate glasses in nuclear waste storage applications. This study also reveals, for the first time, the ability to distinguish between P-O and PO bonding in these rare-earth phosphate glasses from X-ray diffraction data in a fully quantitative manner. Complementary analysis of high-energy X-ray diffraction data on single rare-earth phosphate glasses of similar rare-earth composition to the co-doped materials is also presented in this context. In a technical sense, all high-energy X-ray diffraction data on these glasses are compared with analogous low-energy diffraction data; their salient differences reveal distinct advantages of high-energy X-ray diffraction data for the study of amorphous materials. © 2013 The Owner Societies.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Objective-We previously demonstrated that upregulation of intermediate-conductance Ca2+ -activated K+ channels (KCa 3.1) is necessary for mitogen-induced phenotypic modulation in isolated porcine coronary smooth muscle cells (SMCs). The objective of the present study was to determine the role of KCa3.1 in the regulation of coronary SMC phenotypic modulation in vivo using a swine model of postangioplasty restenosis. Methods and Results-Balloon angioplasty was performed on coronary arteries of swine using either noncoated or balloons coated with the specific KCa3.1 blocker TRAM-34. Expression of KCa3.1, c-jun, c-fos, repressor element-1 silencing transcription factor (REST), smooth muscle myosin heavy chain (SMMHC), and myocardin was measured using qRT-PCR in isolated medial cells 2 hours and 2 days postangioplasty. KCa3.1, c-jun, and c-fos mRNA levels were increased 2 hours postangioplasty, whereas REST expression decreased. SMMHC expression was unchanged at 2 hours, but decreased 2 days postangioplasty. Use of TRAM-34 coated balloons prevented KCa3.1 upregulation and REST downregulation at 2 hours, SMMHC and myocardin downregulation at 2 days, and attenuated subsequent restenosis 14 and 28 days postangioplasty. Immunohistochemical analysis demonstrated corresponding changes at the protein level. Conclusion-Blockade of KCa3.1 by delivery of TRAM-34 via balloon catheter prevented smooth muscle phenotypic modulation and limited subsequent restenosis. © 2008 American Heart Association, Inc.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

We suggest a model for data losses in a single node (memory buffer) of a packet-switched network (like the Internet) which reduces to one-dimensional discrete random walks with unusual boundary conditions. By construction, the model has critical behavior with a sharp transition from exponentially small to finite losses with increasing data arrival rate. We show that for a finite-capacity buffer at the critical point the loss rate exhibits strong fluctuations and non-Markovian power-law correlations in time, in spite of the Markovian character of the data arrival process.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The link between work and welfare is a key pathway of modern welfare state development in Western Europe. National governments face a constant balancing act between the welfare expectations of the labour forces and the labour market liberalisation demands of the business communities. Facilitating the transit from welfare into employment has therefore become an important tool for the British, German and Swedish governments, providing labour as and when needed while keeping welfare expenditure in check. However, the approaches to organising active labour market policies are quite different, notably with regard to the territorial dimension. Although labour markets are quite diverse in all three cases, the role of local authorities, local agencies and local labour market actors from the private and voluntary sector are generally under-developed and apparently under-appreciated, but in different ways and for different reasons. The article compares current employment-related welfare provisions and approaches to develop active labour market policies in the three countries, and concludes that while certain structural and procedural similarities exist, the basic political priorities and actual support and services provided remain very far apart.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

We investigate a class of simple models for Langevin dynamics of turbulent flows, including the one-layer quasi-geostrophic equation and the two-dimensional Euler equations. Starting from a path integral representation of the transition probability, we compute the most probable fluctuation paths from one attractor to any state within its basin of attraction. We prove that such fluctuation paths are the time reversed trajectories of the relaxation paths for a corresponding dual dynamics, which are also within the framework of quasi-geostrophic Langevin dynamics. Cases with or without detailed balance are studied. We discuss a specific example for which the stationary measure displays either a second order (continuous) or a first order (discontinuous) phase transition and a tricritical point. In situations where a first order phase transition is observed, the dynamics are bistable. Then, the transition paths between two coexisting attractors are instantons (fluctuation paths from an attractor to a saddle), which are related to the relaxation paths of the corresponding dual dynamics. For this example, we show how one can analytically determine the instantons and compute the transition probabilities for rare transitions between two attractors.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Measurements were carried out to determine local coefficients of heat transfer in short lengths of horizontal pipe, and in the region of an discontinuity in pipe diameter. Laminar, transitional and turbulent flow regimes were investigated, and mixtures of propylene glycol and water were used in the experiments to give a range of viscous fluids. Theoretical and empirical analyses were implemented to find how the fundamental mechanism of forced convection was modified by the secondary effects of free convection, temperature dependent viscosity, and viscous dissipation. From experiments with the short tube it was possible to determine simple empirical relationships describing the axial distribution of the local 1usselt number and its dependence on the Reynolds and Prandtl numbers. Small corrections were made to account for the secondary effects mentioned above. Two different entrance configurations were investigated to demonstrate how conditions upstream could influence the heat transfer coefficients measured downstream In experiments with a sudden contraction in pipe diameter the distribution of local 1u3se1t number depended on the Prandtl number of the fluid in a complicated way. Graphical data is presented describing this dependence for a range of fluids indicating how the local Nusselt number varied with the diameter-ratio. Ratios up to 3.34:1 were considered. With a sudden divergence in pipe diameter, it was possible to derive the axial distribution of the local Nusse1t number for a range of Reynolds and Prandtl numbers in a similar way to the convergence experiments. Difficulty was encountered in explaining some of the measurements obtained at low Reynolds numbers, and flow visualization techniques wore used to determine the complex flow patterns which could lead to the anomalous results mentioned. Tests were carried out with divergences up to 1:3.34 to find the way in which the local Nusselt number varied with the diameter ratio, and a few experiments were carried out with very large ratios up .to 14.4. A limited amount of theoretical analysis of the 'divergence' system was carried out to substantiate certain explanations of the heat transfer mechanisms postulated.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

A diffusion-controlled electrochemical mass transfer technique has been employed in making local measurements of shell-side coefficients in segmentally baffled shell and tube heat exchangers. Corresponding heat transfer data are predicted through the Chilton and Colburn heat and mass transfer analogy. Mass transfer coefficients were measured for baffle spacing lengths of individual tubes in an internal baffle compartment. Shell-side pressure measurements were also made. Baffle compartment average coefficients derived from individual tube coefficients are shown to be in good agreement with reported experimental bundle average heat transfer data for a heat exchanger model of similar geometry. Mass transfer coefficients of individual tubes compare favourably with those obtained previously by another mass transfer technique. Experimental data are reported for a variety of segmental baffle configurations over the shell-side Reynolds number range 100 to 42 000. Baffles with zero clearances were studied at three baffle cuts and two baffle spacings. Baffle geometry is shown to have a large effect on the distribution of tube coefficients within the baffle compartment. Fluid "jetting" is identified with some baffle configurations. No simple characteristic velocity is found to correlate zonal or baffle compartment average mass transfer data for the effect of both baffle cut and baffle spacing. Experiments with baffle clearances typical of commercial heat exchangers are also reported. The effect of leakage streams associated with these baffles is identified. Investigations were extended to double segmental baffles for which no data had previously been published. The similarity in the shell-side characteristics of this baffle arrangement and two parallel single segmental baffle arrangements is demonstrated. A general relationship between the shell-side mass transfer performance and pressure drop was indicated by the data for all the baffle configurations examined.