982 resultados para DETERMINES


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Agrin is a proteoglycan secreted by motor neurite terminals that functions to initiate and maintain AChR clusters at the nerve terminal. This led to the theory that neurite terminals decide where neuromuscular synapses form by secreting agrin. However, initiation of AChR clustering occurs in the absence of the innervating motoneuron and in the absence of agrin. In this instance, the muscle, not the nerve, is deciding the location of neuromuscular synapses by drawing neurite terminals towards pre-existing AChR clusters. If this were true, one would expect the initial innervation patterns to be the same in agrin-deficient mice and wild-type mice. To test this we quantified the intramuscular axonal branching and synapse formation in the diaphragm at E14.5 in agrin-deficient mice and wild-type mice. Heterozygote mothers were anaesthetised with Nembutal (30 mg) and killed via cervical dislocation. In the diaphragm, the nerve trunk runs down the centre of the muscle and extends branches primarily toward the lateral side. In agrin-deficient mice however, we found significantly more branches exited the phrenic nerve trunk, branched in the periphery and extended further on the medial side. Moreover, we found that the percentage α-bungarotoxin/synaptophysin colocalisations, markers of pre- and postsynaptic differentiation, respectively, was the same in agrin-deficient mice and wild-type mice. These results show that initial innervation patterns are not the same in agrin-deficient mice and wild-type mice indicating neurite terminals, not muscle, decide the placement of neuromuscular synapses in the absence of agrin.

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Abnormal protein aggregates, in the form of either extracellular plaques or intracellular inclusions, are an important pathological feature of the majority of neurodegenerative disorders. The major molecular constituents of these lesions, viz., beta-amyloid (Abeta), tau, and alpha-synuclein, have played a defining role in the diagnosis and classification of disease and in studies of pathogenesis. The molecular composition of a protein aggregate, however, is often complex and could be the direct or indirect consequence of a pathogenic gene mutation, be the result of cell degeneration, or reflect the acquisition of new substances by diffusion and molecular binding to existing proteins. This review examines the molecular composition of the major protein aggregates found in the neurodegenerative diseases including the Abeta and prion protein (PrP) plaques found in Alzheimer's disease (AD) and prion disease, respectively, and the cellular inclusions found in the tauopathies and synucleinopathies. The data suggest that the molecular constituents of a protein aggregate do not directly cause cell death but are largely the consequence of cell degeneration or are acquired during the disease process. These findings are discussed in relation to diagnosis and to studies of to disease pathogenesis.

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This paper draws on data from 73 UK Monopolies and Mergers Commission reports on monopoly between 1973 and 1995. It shows that there is a roughly two in three chance that the Commission will come to an adverse conclusion against the investigated firms in a given case. 75–80% of decisions can be explained purely in terms of the market share of the leading firm and knowledge of the broad nature of the alleged anti-competitive practice. An adverse finding is most likely in cases involving exclusive dealing, and least likely where other vertical restraints are involved.

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We investigate whether inward foreign direct investment (FDI), either at the firm or industry level, has any impact on product innovation by Chinese state-owned enterprises (SOEs). We use a comprehensive firm-level panel data set of some 20,000 SOEs during 1999-2005. Our results show that foreign capital participation at the firm level is associated with higher innovative activity. Inward FDI in the sector, by contrast, has a negative effect on innovative activity in SOEs on average. However, there is a positive effect of sector-level FDI on SOEs that export, invest in human capital, or undertake R&D. © 2008 Elsevier Ltd. All rights reserved.

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This paper disputes the fact that product design determines 70% of costs and the implications that follow for design evaluation tools. Using the idea of decision chains, it is argued that such tools need to consider more of the downstream business activities and should take into account the current and future state of the business rather than some idealized view of it. To illustrate the argument, a series of experiments using an enterprise simulator are described that show the benefit from the application of a more holistic 'design for' technique. Design For the Existing Environment.

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The factors determining the size of individual β-amyloid (A,8) deposits and their size frequency distribution in tissue from Alzheimer's disease (AD) patients have not been established. In 23/25 cortical tissues from 10 AD patients, the frequency of Aβ deposits declined exponentially with increasing size. In a random sample of 400 Aβ deposits, 88% were closely associated with one or more neuronal cell bodies. The frequency distribution of (Aβ) deposits which were associated with 0,1,2,...,n neuronal cell bodies deviated significantly from a Poisson distribution, suggesting a degree of clustering of the neuronal cell bodies. In addition, the frequency of Aβ deposits declined exponentially as the number of associated neuronal cell bodies increased. Aβ deposit area was positively correlated with the frequency of associated neuronal cell bodies, the degree of correlation being greater for pyramidal cells than smaller neurons. These data suggested: (1) the number of closely adjacent neuronal cell bodies which simultaneously secrete Aβ was an important factor determining the size of an Aβ deposit and (2) the exponential decline in larger Aβ deposits reflects the low probability that larger numbers of adjacent neurons will secrete Aβ simultaneously to form a deposit. © 1995.

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Asthenopia, or visual fatigue, is a frequent complaint from observers of stereoscopic three-dimensional displays. It has been proposed that asthenopia is a consequence of anomalous oculomotor responses generated by conflict between accommodative and convergence stimuli. The hypothesis was examined by measuring accommodation and convergence continuously with a Shin-Nippon SRW5000 infrared autorefractor and a limbus tracking device. Subjects viewed a high contrast Maltese Cross target at three levels of Gaussian filter target blur under conditions of relatively low- and high-conflict between accommodation and convergence stimuli, the latter inducing the sensation of stereopsis. Under the low-conflict conditions accommodation was stable, but convergence-driven accommodation was dominant when the target was extremely blurred. Under the high-conflict conditions the role of convergence-driven accommodation increased systematically with the degree of target blur. It is proposed that defocus-driven accommodation becomes weak when the target comprises low spatial frequency components. Large accommodative overshoots to step stimuli that are not blurred or only mildly blurred were consistently observed and are attributed to the initial accommodative response being convergence-driven. Whereas the possibility that high-conflict conditions are a cause of asthenopia has been previously reported, this is the first evidence that they specifically affect accommodative responses while viewing stereoscopic displays. © 2005 Elsevier Ltd. All rights reserved.

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Complex abstract images that are ignored in a simple localization task are subsequently judged more negatively in an emotional evaluation task than previously unseen or attended images, suggesting that attentional inhibition may have affective consequences (Raymond, Fenske, & Tavassoli, in press). We examined the generality of this finding by asking whether inhibitory processes might also influence the generation of emotional responses to unfamiliar faces. To do this, we incorporated an emotional evaluation task within a paradigm that has been used to demonstrate long-term inhibition-of-return (IOR) of attention (Tipper, Grison, & Kessler, in press). On each 2-task trial, observers were first shown a unique pair of unfamiliar faces while performing a speeded go/no-go task. In this task, observers were required to withhold a response if there was an abrupt onset of an exogenous cue (no-go trials), and to make a response if a different stimulus was presented (go ‘catch’ trials). Following the completion of an intervening task, observers where asked to make an affective evaluation about the faces they had previously seen in the go/no-go task (e.g., Which of these people looks more friendly?). We found that observers were less likely to make positive affective responses to faces that attention had been exogenously drawn to in no-go trials than to faces to which attention had never been exogenously allocated. These results converge with our previous finding to suggest that inhibition may be associated with an episode encoded into memory, and that later retrieval acts to reinstate inhibitory processing. Importantly, our results suggest that this inhibitory processing involves affective devaluation, which may serve to encourage examination of new information.

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The present study explored illness perceptions of hearing difficulties amongst one hundred participants who reported experiencing hearing difficulties despite normal audiometric thresholds. This experience is referred to as King-Kopetzky syndrome (KKS), obscure auditory dysfunction (OAD), or auditory processing disorder (APD). Logistic regression was used to consider the associations between help-seeking and a range of audiological and illness perception measures. Results indicate that help-seekers present with poorer speech in noise thresholds than non help-seekers, and that coherent illness perceptions and a negative belief in the consequences of hearing difficulties are associated with help-seeking status, regardless of hearing sensitivity.

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This paper examines the determinants of a multinational enterprise’s (MNEs) decision to invest in countries classified as tax havens. To the best of our knowledge this has not been analysed at the cross-country level before. We use the ownership-location-internalisation (OLI) paradigm and link it with financial specific advantages to develop a number of hypotheses which are subsequently tested by our empirical model. Our analysis is based on a large firm-level database covering 39,543 MNEs across the world for the period 2002- 2011. We find that higher corporate taxes faced by MNEs at home increase the likelihood of locating in a tax haven. Moreover, high technology manufacturing and services MNEs that possess large levels of intangible assets are also more likely to locate subsidiaries in tax havens. Finally, we find evidence that MNEs from countries with a more coordinated market orientation are less likely to locate in tax havens.

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Investors and developers are often faced with the task of determining the worth or value of a real estate entity that presently exists or is proposed for development. This article explains the process for determining the value of a proposed project and, subsequently, the maximum investment dollars the project can cover, while at the same time producing a reasonable return for the investor. A proposed 300-room hotel serves as the real estate entity to be analyzed.

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The authors would like to thank the participants of the Aberdeen 1936 Birth Cohort (ABC36). Image acquisition and image analysis for ABC36 were funded by the Alzheimer’s Research Trust (now Alzheimer’s Research UK). A.D.M., C.J.M., S.S., L.J.W., and R.T.S. have received grants from: Chief Scientist Office, Department of Health, Scottish Government; Biotechnology and Biological Sciences Research Council