921 resultados para Somatic Mutation and Recombination Test
Resumo:
Purpose – This paper attempts to seek answers to four questions. Two of these questions have been borrowed (but adapted) from the work of Defee et al.: RQ1. To what extent is theory used in purchasing and supply chain management (P&SCM) research? RQ2. What are the prevalent theories to be found in P&SCM research? Following on from these questions an additional question is posed: RQ3. Are theory-based papers more highly cited than papers with no theoretical foundation? Finally, drawing on the work of Harland et al., the authors have added a fourth question: RQ4. To what extent does P&SCM meet the tests of coherence, breadth and depth, and quality necessary to make it a scientific discipline? Design/methodology/approach – A systematic literature review was conducted in accordance with the model outlined by Tranfield et al. for three journals within the field of “purchasing and supply chain management”. In total 1,113 articles were reviewed. In addition a citation analysis was completed covering 806 articles in total. Findings – The headline features from the results suggest that nearly a decade-and-a-half on from its development, the field still lacks coherence. There is the absence of theory in much of the work and although theory-based articles achieved on average a higher number of citations than non-theoretical papers, there is no obvious contender as an emergent paradigm for the discipline. Furthermore, it is evident that P&SCM does not meet Fabian's test necessary to make it a scientific discipline and is still some way from being a normal science. Research limitations/implications – This study would have benefited from the analysis of further journals, however the analysis of 1,113 articles from three leading journals in the field of P&SCM was deemed sufficient in scope. In addition, a further significant line of enquiry to follow is the rigour vs relevance debate. Practical implications – This article is of interest to both an academic and practitioner audience as it highlights the use theories in P&SCM. Furthermore, this article raises a number of important questions. Should research in this area draw more heavily on theory and if so which theories are appropriate? Social implications – The broader social implications relate to the discussion of how a scientific discipline develops and builds on the work of Fabian and Amundson. Originality/value – The data set for this study is significant and builds on a number of previous literature reviews. This review is both greater in scope than previous reviews and is broader in its subject focus. In addition, the citation analysis (not previously conducted in any of the reviews) and statistical test highlights that theory-based articles are more highly cited than non-theoretically based papers. This could indicate that researchers are attempting to build on one another's work.
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In industrial selling situations, the questions of what factors drive pricing authority delegation to salespeople and under what conditions price delegation is beneficial for the firm are often asked. To advance knowledge in this area, we (1) develop and empirically test a framework of important drivers of price delegation based on agency-theoretic research and (2) investigate the impact of price delegation on firm performance, taking into account agency theory variables as potential moderators. The study is based on data from a sample of 181 companies from the industrial machinery and electrical engineering industry in Germany. The results indicate that the degree of pricing delegation increases as information asymmetry between the salesperson and sales manager increases and as it becomes more difficult to monitor salespeople's efforts. Conversely, risk-aversion of salespeople is negatively related to the degree of price delegation. Furthermore, we find a positive effect of price delegation on firm performance, which is amplified when market-related uncertainty is high and when salespeople possess better customer-related information than their managers. Hence, our results clearly show that rigid, “one price fits all” policies are inappropriate in many B2B market situations. Instead, sales managers should grant their salespeople sufficient leeway to adapt prices to changing customer requirements and market conditions, especially in firms that operate in highly uncertain selling environments.
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Aims: Humans with inactivating mutations in peroxisomal proliferators activated receptor gamma (PPAR?) typically develop a complex metabolic syndrome characterized by insulin resistance, diabetes, lipodystrophy, hypertension, and dyslipidaemia which is likely to increase their cardiovascular risk. Despite evidence that the activation of PPAR? may prevent cardiac fibrosis and hypertrophy, recent evidence has suggested that pharmacological activation of PPAR? causes increased cardiovascular mortality. In this study, we investigated the effects of defective PPAR? function on the development of cardiac fibrosis and hypertrophy in a murine model carrying a human dominant-negative mutation in PPAR?. Methods and results: Mice with a dominant-negative point mutation in PPAR? (P465L) and their wild-type (WT) littermates were treated with either subcutaneous angiotensin II (AngII) infusion or saline for 2 weeks. Heterozygous P465L and WT mice developed a similar increase in systolic blood pressure, but the mutant mice developed significantly more severe cardiac fibrosis to AngII that correlated with increased expression of profibrotic genes. Both groups similarly increased the heart weight to body weight ratio compared with saline-treated controls. There were no differences in fibrosis between saline-treated WT and P465L mice. Conclusion: These results show synergistic pathogenic effects between the presence of defective PPAR? and AngII-induced hypertension and suggest that patients with PPAR? mutation and hypertension may need more aggressive therapeutic measures to reduce the risk of accelerated cardiac fibrosis. © The Author 2009.
Resumo:
Purpose – This study proposes to use the Theory of Planned Behaviour to predict entrepreneurial intentions among students in five developing and nine developed countries. The purpose is to investigate whether entrepreneurial intention and its antecedents differ between developing and developed countries, and to test the theory in the two groups of countries. Design/methodology/approach – A total of 2,225 students in 13 countries participated in this study by responding to a structured questionnaire in classrooms. Structural equation modelling was used to analyse the data. Findings – The findings indicate that respondents from developing countries have stronger entrepreneurial intentions than those from developed countries. Moreover, the respondents from developing countries also score higher on the theory's antecedents of entrepreneurial intentions – attitudes, subjective norms, and perceived behavioural control – than respondents from developed countries. The findings support the Theory of Planned Behaviour in both developing and developed countries. Research limitations/implications – The findings strongly support the Theory of Planned Behaviour. The measure of subjective norms used, a multiple-item index encompassing the views of other people and motivation to comply with these, seems to have advantages over other measures of this concept. Practical implications – Developing countries need to focus on the development of institutions that can support entrepreneurial efforts. At the same time, developed economies may need to accept that entrepreneurial intentions are dependent on the dynamism of an economic environment and possibly on risk-perceiving behaviours. Originality/value – While multiple-country studies on entrepreneurship in developing and developed countries have been called for, no previous study has compared entrepreneurial intentions between developing and developed countries. The inclusion of developing countries provides a unique quasi-experimental setting in which to test the theory.
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Familial frontotemporal lobar degeneration with transactive response (TAR) DNA-binding protein of 43 kDa (TDP-43) proteinopathy (FTLD-TDP) is most commonly caused by progranulin (GRN) gene mutation. To characterize cortical degeneration in these cases, changes in density of the pathology across the cortical laminae of the frontal and temporal lobe were studied in seven cases of FTLD-TDP with GRN mutation using quantitative analysis and polynomial curve fitting. In 50% of gyri studied, neuronal cytoplasmic inclusions (NCI) exhibited a peak of density in the upper cortical laminae. Most frequently, neuronal intranuclear inclusions (NII) and dystrophic neurites (DN) exhibited a density peak in lower and upper laminae, respectively, glial inclusions (GI) being distributed in low densities across all laminae. Abnormally enlarged neurons (EN) were distributed either in the lower laminae or were more uniformly distributed across the cortex. The distribution of all neurons present varied between cases and regions, but most commonly exhibited a bimodal distribution, density peaks occurring in upper and lower laminae. Vacuolation primarily affected the superficial laminae and density of glial cell nuclei increased with distance across the cortex from pia mater to white matter. The densities of the NCI, GI, NII, and DN were not spatially correlated. The laminar distribution of the pathology in GRN mutation cases was similar to previously reported sporadic cases of FTLD-TDP. Hence, pathological changes initiated by GRN mutation, and by other causes in sporadic cases, appear to follow a parallel course resulting in very similar patterns of cortical degeneration in FTLD-TDP.
Resumo:
BACKGROUND: Contrast detection is an important aspect of the assessment of visual function; however, clinical tests evaluate limited spatial frequencies and contrasts. This study validates the accuracy and inter-test repeatability of a swept-frequency near and distance mobile app Aston contrast sensitivity test, which overcomes this limitation compared to traditional charts. METHOD: Twenty subjects wearing their full refractive correction underwent contrast sensitivity testing on the new near application (near app), distance app, CSV-1000 and Pelli-Robson charts with full correction and with vision degraded by 0.8 and 0.2 Bangerter degradation foils. In addition repeated measures using the 0.8 occluding foil were taken. RESULTS: The mobile apps (near more than distance, p = 0.005) recorded a higher contrast sensitivity than printed tests (p < 0.001); however, all charts showed a reduction in measured contrast sensitivity with degradation (p < 0.001) and a similar decrease with increasing spatial frequency (interaction > 0.05). Although the coefficient of repeatability was lowest for the Pelli-Robson charts (0.14 log units), the mobile app charts measured more spatial frequencies, took less time and were more repeatable (near: 0.26 to 0.37 log units; distance: 0.34 to 0.39 log units) than the CSV-1000 (0.30 to 0.93 log units). The duration to complete the CSV-1000 was 124 ± 37 seconds, Pelli-Robson 78 ± 27 seconds, near app 53 ± 15 seconds and distance app 107 ± 36 seconds. CONCLUSIONS: While there were differences between charts in contrast levels measured, the new Aston near and distance apps are valid, repeatable and time-efficient method of assessing contrast sensitivity at multiple spatial frequencies.