15 resultados para diverse cohorts

em Aston University Research Archive


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The introduction of accounting and auditing oversight boards (OBs) has been promoted on a global scale as a key component of the international financial architecture that has emerged over the past two decades. Such institutions, modeled on the Anglo-American tradition, are domestically organized and embedded within distinctively diverse institutional contexts. Their role is to ease agency problems, improve the quality of financial reporting, and help provide stability in the global financial system. We employ an institutional approach, located within the broader political economy framework of global capitalism, to examine the establishment and operation of the new regulatory regime in Greece. Greece, a member of the European Union, exhibits characteristics of a "delegative" democracy, i.e. a traditionally weak institutionalization, reform (in)capacity problems and a clientelistic political system. Our case study shows that the formation and operation of the newly-established system of oversight is conditioned by local political and economic constraints and, thus, does not automatically translate into concrete benefits for the quality of financial reporting. We also draw attention to the structural mismatch between a progressing globalized financial integration and the fragmented nature of the system of oversight, and illustrate that OBs' independence from local governments is an important but neglected issue.

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Orexins A and B (ORA and ORB) are neuropeptide hormones found throughout the central nervous system and periphery. They are required for a host of physiological processes including mitogen-activated protein kinase (MAPK) regulation, steroidogenesis, appetite control and energy regulation. While some signalling mechanisms have been proposed for individual recombinant orexin receptors in generic mammalian cell types, it is clear that the peripheral effects of orexin are spatially and temporally complex. This study dissects the different G-protein signalling and MAPK pathways activated in a pluripotent human adrenal H295R cell line capable of all the physiological steps involved in steroidogenesis. Both extracellular receptor kinase 1/2 (ERK1/2) and p38 were phosphorylated rapidly with a subsequent decline, in a time- and dose-dependent manner, in response to both ORA and ORB. Conversely, there was little or no direct activation of the ERK5 or JNK pathway. Analysis using signalling and MAPK inhibitors as well as receptor-specific antagonists determined the precise mediators of the orexin response in these cells. Both ERK1/2 and p38 activation were predominantly Gq- and to a lesser extent Gs-mediated; p38 activation even had a small Gi-component. Effects were broadly comparable for both orexin sub-types ORA and ORB and although most of the effects were transmitted through the orexin receptor-1 subtype, we did observe a role for orexin receptor-2-mediated activation of both ERK1/2 and p38. Cortisol secretion also differed in response to ORA and ORB. These data suggest multiple roles for orexin-mediated MAPK activation in an adrenal cell-line, this complexity may help to explain the diverse biological actions of orexins with wide-ranging consequences for our understanding of the mechanisms initiated by these steroidogenic molecules.

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The CGRP1 receptor exists as a heterodimeric complex between a single-pass transmembrane accessory protein (RAMP1) and a family B G-protein-coupled receptor (GPCR) called the calcitonin receptor-like receptor (CLR). This study investigated the structural motifs found in the intracellular loops (ICLs) of this receptor. Molecular modeling was used to predict active and inactive conformations of each ICL. Conserved residues were altered to alanine by site-directed mutagenesis. cAMP accumulation, cell-surface expression, agonist affinity, and CGRP-stimulated receptor internalization were characterized. Within ICL1, L147 and particularly R151 were important for coupling to Gs. R151 may interact directly with the G-protein, accessing it following conformational changes involving ICL2 and ICL3. At the proximal end of ICL3, I290 and L294, probably lying on the same face of an α helix, formed a G-protein coupling motif. The largest effects on coupling were observed with I290A; additionally, it reduced CGRP affinity and impaired internalization. 1290 may interact with TM6 to stabilize the conformation of ICL3, but it could also interact directly with Gs. R314, at the distal end of ICL3, impaired G-protein coupling and to a lesser extent reduced CGRP affinity; it may stabilize the TM6-ICL3 junction by interacting with the polar headgroups of membrane phospholipids. Y215 and L214 in ICL2 are required for cell-surface expression; they form a microdomain with H216 which has the same function. This study reveals similarities between the activation of CLR and other GPCRs in the role of TM6 and ICL3 but shows that other conserved motifs differ in their function. © 2006 American Chemical Society.

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Digital back-propagation (DBP) has recently been proposed for the comprehensive compensation of channel nonlinearities in optical communication systems. While DBP is attractive for its flexibility and performance, it poses significant challenges in terms of computational complexity. Alternatively, phase conjugation or spectral inversion has previously been employed to mitigate nonlinear fibre impairments. Though spectral inversion is relatively straightforward to implement in optical or electrical domain, it requires precise positioning and symmetrised link power profile in order to avail the full benefit. In this paper, we directly compare ideal and low-precision single-channel DBP with single-channel spectral-inversion both with and without symmetry correction via dispersive chirping. We demonstrate that for all the dispersion maps studied, spectral inversion approaches the performance of ideal DBP with 40 steps per span and exceeds the performance of electronic dispersion compensation by ~3.5 dB in Q-factor, enabling up to 96% reduction in complexity in terms of required DBP stages, relative to low precision one step per span based DBP. For maps where quasi-phase matching is a significant issue, spectral inversion significantly outperforms ideal DBP by ~3 dB.

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Accounts of Tamil long-distance nationalism have focused on Sri Lankan Tamil migrants. But the UK is also home to Tamils of non-Sri Lankan state origins. While these migrants may be nominally incorporated into a 'Tamil diaspora', they are seldom present in scholarly accounts. Framed by Werbner's (2002) conception of diasporas as 'aesthetic' and 'moral' communities, this article explores whether engagement with a Tamil diaspora and long-distance nationalism is expressed by Tamil migrants of diverse state origins. While migrants identify with an aesthetic community, 'membership' of the moral community is contested between those who hold direct experience of suffering as central to belonging, and those who imagine the boundaries of belonging more fluidly - based upon primordial understandings of essential ethnicity and a narrative of Tamil 'victimhood' that incorporates experiences of being Tamil in Sri Lanka, India and in other sites, despite obvious differences in these experiences. © 2013 Taylor & Francis.

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Polarization diverse optical phase conjugation of a 1THz spectral-band 1.14Tb/s DP-QPSK WDM multiplex is demonstrated for the first time, showing a worst case Q2 penalty of 0.9dB over all conjugate wavelengths, polarizations and OSNR. © 2014 OSA.

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Optical phase conjugation (OPC) of a polarization-multiplexed comb of 10x114Gb/s DP-QPSK signals has been demonstrated for the first time, occupying a spectral bandwidth of >1THz (~9nm). The nonlinear element employed for the OPC was highly nonlinear fiber (HNLF) optimized for the suppression of stimulated Brillouin scattering (SBS) and configured in a bi-directional loop offering polarization diversity. Pump power (each way about the loop) and input signal power to the OPC subsystem were optimized at 29.7dBm and + 3dBm respectively producing a Q2 penalty of ≤0.9dB over all conjugate wavelengths, polarizations and output OSNR (up to 20dB).

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REDOX responsive (nano)materials typically exhibit chemical changes in response to the presence and concentration of oxidants/reductants. Due to the complexity of biological environments, it is critical to ascertain whether the chemical response may depend on the chemical details of the stimulus, in addition to its REDOX potential, and whether chemically different responses can determine a different overall performance of the material. Here, we have used oxidation-sensitive materials, although these considerations can be extended also to reducible ones. In particular, we have used poly(propylene sulfide) (PPS) nanoparticles coated with a PEGylated emulsifier (Pluronic F127); inter alia, we here present also an improved preparative method. The nanoparticles were exposed to two Reactive Oxygen Species (ROS) typically encountered in inflammatory reactions, hydrogen peroxide (H2O2) and hypochlorite (ClO−); their response was evaluated with a variety of techniques, including diffusion NMR spectroscopy that allowed to separately characterize the chemically different colloidal species produced. The two oxidants triggered a different chemical response: H2O2 converted sulfides to sulfoxides, while ClO− partially oxidized them further to sulfones. The different chemistry correlated to a different material response: H2O2 increased the polarity of the nanoparticles, causing them to swell in water and to release the surface PEGylated emulsifier; the uncoated oxidized particles still exhibited very low toxicity. On the contrary, ClO− rapidly converted the nanoparticles into water-soluble, depolymerized fragments with a significantly higher toxicity. The take-home message is that it is more correct to discuss ‘smart’ materials in terms of an environmentally specific response to (REDOX) stimuli. Far from being a problem, this could open the way to more sophisticated and precisely targeted applications.

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This chapter employs Pnina Werbner's notion of diasporas as moral communities of suffering and co-responsibility, as well as aesthetic communities of shared transnational consumption of culture and performance of ritual, and relates this to the case of Tamil migrants of diverse state origins in Britain. Sri Lankan Tamil migrants I interviewed towards my research imagine membership of a Tamil diaspora as based on personal (or familial) experiences of suffering in the Sri Lankan civil war, which acts both to create bonds with other Sri Lankan Tamils, and to distinguish from Tamils of other state origins (Indian, Singaporean etc.) despite cultural commonalities (Werbner's aesthetic diaspora). Conversely, many of the non-Sri Lankan Tamil migrants I interviewed imagined these boundaries in more flexible terms, and claimed membership of the 'community of suffering' in ways which did not necessitate personal experience, but rather privileged symbolic constructions of the ethnic community, and an interpretation of historical and current events in India, Sri Lanka (and other sites of Tamil population) as components of a single narrative of Tamil victimhood.

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Background - Aquaporin (AQP) water channels are best known as passive transporters of water that are vital for water homeostasis. Scope of review - AQP knockout studies in whole animals and cultured cells, along with naturally occurring human mutations suggest that the transport of neutral solutes through AQPs has important physiological roles. Emerging biophysical evidence suggests that AQPs may also facilitate gas (CO2) and cation transport. AQPs may be involved in cell signalling for volume regulation and controlling the subcellular localization of other proteins by forming macromolecular complexes. This review examines the evidence for these diverse functions of AQPs as well their physiological relevance. Major conclusions - As well as being crucial for water homeostasis, AQPs are involved in physiologically important transport of molecules other than water, regulation of surface expression of other membrane proteins, cell adhesion, and signalling in cell volume regulation. General significance - Elucidating the full range of functional roles of AQPs beyond the passive conduction of water will improve our understanding of mammalian physiology in health and disease. The functional variety of AQPs makes them an exciting drug target and could provide routes to a range of novel therapies.

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Methods - Ethical approval for the study was granted by both the local National Health Service (NHS) Research Ethics Committee (REC) and Aston University’s REC. Seven focus groups were conducted between October and December 2011 in medical or community settings within inner-city Birmingham (UK). Discussions were guided by a theme plan which was developed from key themes identified by a literature review and piloted via a Patient Consultation Group. Each focus group had between 3 and 7 participants. The groups were digitally recorded and subsequently transcribed verbatim. The transcriptions were then subjected to thematic analysis via constant comparison in order to identify emerging themes. Results - Participants recognised the pharmacist as an expert source of advice about prescribed medicines, a source they frequently felt a need to consult as a result of the inadequate supply of medicines information from the prescriber. However, an emerging theme was a perception that pharmacists had an oblique profit motive relating to the supply of generic medicines with frequent changes to the ‘brand’ of generic supplied being attributed to profit-seeking by pharmacists. Such changes had a negative impact on the patient’s perceived efficacy of the therapy which may make non-adherence more likely. Conclusions - Whilst pharmacists were recognised as medicines experts, trust in the pharmacist was undermined by frequent changes to generic medicines. Such changes have the potential to adversely impact adherence levels. Further, quantitative research is recommended to examine if such views are generalisable to the wider population of Birmingham and to establish if such views impact on adherence levels.

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Although most anti-epileptic drugs are considered to have a primary molecular target, it is clear that their actions are unlikely to be limited to effects on a single aspect of inhibitory synaptic transmission, excitatory transmission or voltage-gated ion channels. Systemically administered drugs can obviously simultaneously access all possible targets, so we have attempted to determine the overall effect of diverse agents on the balance between GABAergic inhibition, glutamatergic excitation and cellular excitability in neurones of the rat entorhinal cortex in vitro. We used an approach developed for estimating global background synaptic excitation and inhibition from fluctuations in membrane potential obtained by intracellular recordings. We have previously validated this approach in entorhinal cortical neurones [. Greenhill and Jones (2007a) Neuroscience 147:884-892]. Using this approach, we found that, despite their differing pharmacology, the drugs tested (phenytoin, lamotrigine, valproate, gabapentin, felbamate, tiagabine) were unified in their ability to increase the ratio of background GABAergic inhibition to glutamatergic excitation. This could occur as a result of decreased excitation concurrent with increased inhibition (phenytoin, lamotrigine, valproate), a decrease in excitation alone (gabapentin, felbamate), or even with a differential increase in both (tiagabine). Additionally, we found that the effects on global synaptic conductances agreed well with whole cell patch recordings of spontaneous glutamate and GABA release (our previous studies and further data presented here). The consistency with which the synaptic inhibition:excitation ratio was increased by the antiepileptic drugs tested was matched by an ability of all drugs to concurrently reduce intrinsic neuronal excitability. Thus, it seems possible that specific molecular targets among antiepileptic drugs are less important than the ability to increase the inhibition:excitation ratio and reduce overall neuronal and network excitability. © 2010 IBRO.

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This paper examines how the introduction and use of a new information system affects and is affected by the values of a diverse professional workforce. It uses the example of lecture capture systems in a university. Its contribution is to combine two concepts taken from actor-network theory, namely accumulation and inscription, and combine them with an integrated framework of diversity management. A model is developed of accumulation cycles in lecture capture usage, involving multiple interacting actants, including the broader environment, management commitment to diversity, work group characteristics, individual practices and the affordances of technology. Using this model, alternative future inscriptions can be identified - an optimal one, which enhances professional values, as a result of a virtuous accumulation cycle, or a sub-optimal one, as a result of a vicious cycle. It identifies diversity management as an important influence on how professional values are enhanced, modified or destroyed.