799 resultados para Cross Spectrum Analysis


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Background: Inflammatory markers are increased in chronic obstructive pulmonary disease ( COPD) and are hypothesised to play an important part in muscle dysfunction and exercise intolerance. Methods: The Health Aging and Body Composition ( Health ABC) study is a prospective observational cohort of well functioning individuals aged 70 - 79 years. A cross sectional analysis of the baseline data was conducted to examine the association between inflammatory markers and ventilatory limitation, muscle strength, and exercise capacity. These associations were compared in participants with and without obstructive lung disease ( OLD). Results: Of the 3075 participants enrolled in the Health ABC cohort, OLD was identified by spirometric testing in 268 participants and 2005 participants had normal spirometric results. Of the participants with OLD, 35%, 38%, and 27% participants had mild, moderate, and severe OLD, respectively. Participants with OLD had lower quadriceps strength (102.5 Nm v 108.9 Nm, p = 0.02), lower maximum inspiratory pressure (64.7 cm H2O v 74.2 cm H2O, p< 0.0001), higher systemic interleukin (IL)-6 levels (2.6 pg/ml v 2.2 pg/ml, p< 0.0001), and higher C-reactive protein (CRP) levels (3.5 mg/l v 2.5 mg/l, p< 0.0001) than those with normal spirometry. In participants with OLD and those with normal spirometry, forced expiratory volume in 1 second (FEV1) was associated with IL-6 ( adjusted regression coefficients (beta) = -5.3 (95% CI -9.1 to -1.5) and -3.1 (95% CI -4.3 to -1.9), respectively). IL-6 and TNF were also associated with quadriceps strength among participants with OLD and those with normal spirometry (beta = -6.4 (95% CI -12.8 to -0.03) and -3.4 (95% CI -5.4 to -1.3), respectively, for IL-6 and beta = -10.1 (95% CI -18.7 to -1.5) and -3.8 (95% CI -7 to -0.6), respectively, for TNF). IL-6, quadriceps strength, and maximum inspiratory pressures were independent predictors of reduced exercise capacity in both groups. Conclusions: In well functioning elderly subjects with or without OLD, IL-6 is associated with reduced FEV1, quadriceps strength, and exercise capacity.

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This study presents an empirical investigation of the UK stock market response to the im-plementation of the UK Statement of Standard Accounting Practice (SSAP) No. 20 “Foreign Cur-rency Translation” (issued in April 1983). Such an empirical investigation has not yet been under-taken for the UK. Our results show that the stock market generally appeared to have anticipatedthe implementation of SSAP 20. For the aggregate set of adopters, we found a positive stock mar-ket response in the official year of adoption, reflecting the appreciation of the income-stabilisingeffects of the standard. This paper also presents a cross-sectional analysis that tests for a relation-ship between the stock returns and the accounting measures of those firms that adopted SSAP 20.We found a significant relation between the stock returns and the related accounting measures inthe actual adoption period of the aggregate set of adopters. This study generally focuses on theinterpretation of the financial impacts of the various accounting choices of firms within their fi-nancial and economic environments.

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Using an event study approach, this article reports evidence that the UK Treasury bond market displayed anomalous pricing behaviour in the secondary market both immediately before and after auctions of seasoned bonds. Using a benchmark return derived from the behaviour of the underlying yield curve, the market offered statistically and economically significant excess returns, around the auctions held between 1992 and 2004. A cross-sectional analysis of the cumulative excess returns shows that the excess demand at the auctions is a key determinant of this excess return.

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This thesis investigates the pricing-to-market (PTM) behaviour of the UK export sector. Unlike previous studies, this study econometrically tests for seasonal unit roots in the export prices prior to estimating PTM behaviour. Prior studies have seasonally adjusted the data automatically. This study’s results show that monthly export prices contain very little seasonal unit roots implying that there is a loss of information in the data generating process of the series when estimating PTM using seasonally-adjusted data. Prior studies have also ignored the econometric properties of the data despite the existence of ARCH effects in such data. The standard approach has been to estimate PTM models using Ordinary Least Square (OLS). For this reason, both EGARCH and GJR-EGARCH (hereafter GJR) estimation methods are used to estimate both a standard and an Error Correction model (ECM) of PTM. The results indicate that PTM behaviour varies across UK sectors. The variables used in the PTM models are co-integrated and an ECM is a valid representation of pricing behaviour. The study also finds that the price adjustment is slower when the analysis is performed on real prices, i.e., data that are adjusted for inflation. There is strong evidence of auto-regressive condition heteroscedasticity (ARCH) effects – meaning that the PTM parameter estimates of prior studies have been ineffectively estimated. Surprisingly, there is very little evidence of asymmetry. This suggests that exporters appear to PTM at a relatively constant rate. This finding might also explain the failure of prior studies to find evidence of asymmetric exposure in foreign exchange (FX) rates. This study also provides a cross sectional analysis to explain the implications of the observed PTM of producers’ marginal cost, market share and product differentiation. The cross-sectional regressions are estimated using OLS, Generalised Method of Moment (GMM) and Logit estimations. Overall, the results suggest that market share affects PTM positively.Exporters with smaller market share are more likely to operate PTM. Alternatively, product differentiation is negatively associated with PTM. So industries with highly differentiated products are less likely to adjust their prices. However, marginal costs seem not to be significantly associated with PTM. Exporters perform PTM to limit the FX rate effect pass-through to their foreign customers, but they also avoided exploiting PTM to the full, since to do so can substantially reduce their profits.

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The study is a two-part study starting with a nationwide survey in the private sector. The hypotheses derived from the Western literature were not significantly supported when the results were analyzed. It seems that the existing literature related to the phenomenon under investigation is mainly Anglo-Saxon culture oriented which is different from the Malaysian culture where the study was conducted. However, access barriers to private sector organizations shifted the focus of the research to the second part of the study that examined the issues in detail in four public sector organizations currently implementing accounting information systems – two hospitals and two universities. In the second part of the main study, the researcher developed formal and substantive propositions from the qualitative interviews which were substantiated using a cross-case analysis; as a result, a model for accountants’ participation in AIS implementation is proposed. The research shows that the process of influencing accountants to participate in AIS implementation is more complex than the literature suggests. There were many issues that surfaced during the case studies, such as conflict and empowerment which set a foundation for further research about how participation can be secured to help make the implementation of AIS part of an organizational agenda success.

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A systematic analysis is presented of the economic consequences of the abnormally high concentration of Zambia's exports on a commodity whose price is exceptionally unstable. Zambian macro-economic variables in the post-independence years are extensively documented, showing acute instability and decline, particularly after the energy price revolution and the collapse of copper prices. The relevance of stabilization policies designed to correct short-term disequilibrium is questioned. It is, therefore, a pathological case study of externally induced economic instability, complementing other studies in this area which use cross-country analysis of a few selected variables. After a survey of theory and issues pertaining to development, finance and stabilization, the emergence of domestic and foreign financial constraints on the Zambian economy is described. The world copper industry is surveyed and an examination of commodity and world trade prices concludes that copper showed the highest degree of price instability. Specific aspects of Zambia's economy identified for detailed analysis include: its unprofitable mining industry, external payments disequilibrium, a constrained government budget, potentially inflationary monetary growth, and external indebtedness. International comparisons are used extensively, but major copper exporters are subjected to closer scrutiny. An appraisal of policy options concludes the study.

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Objective: Qualitative research is increasingly valued as part of the evidence for policy and practice, but how it should be appraised is contested. Various appraisal methods, including checklists and other structured approaches, have been proposed but rarely evaluated. We aimed to compare three methods for appraising qualitative research papers that were candidates for inclusion in a systematic review of evidence on support for breast-feeding. Method: A sample of 12 research papers on support for breast-feeding was appraised by six qualitative reviewers using three appraisal methods: unprompted judgement, based on expert opinion; a UK Cabinet Office quality framework; and CASP, a Critical Appraisal Skills Programme tool. Papers were assigned, following appraisals, to 1 of 5 categories, which were dichotomized to indicate whether or not papers should be included in a systematic review. Patterns of agreement in categorization of papers were assessed quantitatively using κ statistics, and qualitatively using cross-case analysis. Results: Agreement in categorizing papers across the three methods was slight (κ =0.13; 95% CI 0.06-0.24). Structured approaches did not appear to yield higher agreement than that by unprompted judgement. Qualitative analysis revealed reviewers' dilemmas in deciding between the potential impact of findings and the quality of the research execution or reporting practice. Structured instruments appeared to make reviewers more explicit about the reasons for their judgements. Conclusions: Structured approaches may not produce greater consistency of judgements about whether to include qualitative papers in a systematic review. Future research should address how appraisals of qualitative research should be incorporated in systematic reviews. © The Royal Society of Medicine Press Ltd 2007.

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Previous work has indicated the presence of collapsing and structured soils in the surface layers underlying Sana's, the capital of Yemen Republic. This study set out initially to define and, ultimately, to alleviate the problem by investigating the deformation behaviour of these soils through both field and laboratory programmes. The field programme was carried out in Sana'a while the laboratory work consisted of two parts, an initial phase at Sana's University carried out in parallel with the field programme on natural and treated soils and the major phase at Aston University carried out on natural, destructured and selected treated soils. The initial phase of the laboratory programme included classification, permeability, and single (collapsing) and double oedometer tests while the major phase, at Aston, was extended to also include extensive single and double oedometer tests, Scanning Electron Microscopy and Energy Dispersive Spectrum analysis. The mechanical tests were carried out on natural and destructed samples at both the in situ and soaked moisture conditions. The engineering characteristics of the natural intact, field-treated and laboratory destructured soils are reported, including their collapsing potentials which show them to be weakly bonded with nil to severe collapsing susceptibility. Flooding had no beneficial effect, with limited to moderate improvement being achieved by preloading and roller compaction, while major benefits were achieved from deep compaction. From these results a comparison between the soil response to the different treatments and general field remarks were presented. Laboratory destructuring reduced the stiffness of the soils while their compressibility was increasing. Their collapsing and destructuring mechanisms have been examined by studying the changes in structure accompanying these phenomena. Based on the test results for the intact and the laboratory destructured soils, a simplified framework has been developed to represent the collapsing and deformation behaviour at both the partially saturated and soaked states, and comments are given on its general applicability and limitations. It has been used to evaluate all the locations subjected to field treatment. It provided satisfactory results for the deformation behaviour of the soils destructed by field treatment. Finally attention is drawn to the design considerations together with the recommendations for the selection of potential improvement techniques to be used for foundation construction on the particular soils of the Sana's region.

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An experimental testing system for the study of the dynamic behavior of fluid-loaded rectangular micromachined silicon plates is designed and presented in this paper. In this experimental system, the base-excitation technique combined with pseudo-random signal and cross-correlation analysis is applied to test fluid-loaded microstructures. Theoretical model is also derived to reveal the mechanism of such an experimental system in the application of testing fluid-loaded microstructures. The dynamic experiments cover a series of testings of various microplates with different boundary conditions and dimensions, both in air and immersed in water. This paper is the first that demonstrates the ability and performances of base excitation in the application of dynamic testing of microstructures that involves a natural fluid environment. Traditional modal analysis approaches are used to evaluate natural frequencies, modal damping and mode shapes from the experimental data. The obtained experimental results are discussed and compared with theoretical predictions. This research experimentally determines the dynamic characteristics of the fluid-loaded silicon microplates, which can contribute to the design of plate-based microsystems. The experimental system and testing approaches presented in this paper can be widely applied to the investigation of the dynamics of microstructures and nanostructures.

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This paper presents a study of engineering design groups that seeks to explain how knowing other participants can influence processes and outcomes in design projects. Research in this paper contributes a framework to approach understanding how interpersonal relationships influence group processes and outcomes. This acknowledges that engineering design is achieved through individuals working in groups. First a temporal perspective is introduced to understand how individuals (through interpersonal relationships), group processes and outcomes influence each other; secondly identity is presented as a theme to focus on how knowing other participants identity influences group processes and outcomes. Within this framework it is recognised that engineering design has different levels of complexity of which two aspects are considered: design type and design setting. These aspects place different demands on a project group and its members and this structure provides an opportunity for cross case analysis to generalise findings.

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This thesis addresses the question of how business schoolsestablished as public privatepartnerships (PPPs) within a regional university in the English-speaking Caribbean survived for over twenty-one years and achieved legitimacy in their environment. The aim of the study was to examine how public and private sector actors contributed to the evolution of the PPPs. A social network perspective provided a broad relational focus from which to explore the phenomenon and engage disciplinary and middle-rangetheories to develop explanations. Legitimacy theory provided an appropriate performance dimension from which to assess PPP success. An embedded multiple-case research design, with three case sites analysed at three levels including the country and university environment, the PPP as a firm and the subgroup level constituted the methodological framing of the research process. The analysis techniques included four methods but relied primarily on discourse and social network analysis of interview data from 40 respondents across the three sites. A staged analysis of the evolution of the firm provided the ‘time and effects’ antecedents which formed the basis for sense-making to arrive at explanations of the public-private relationship-influenced change. A conceptual model guided the study and explanations from the cross-case analysis were used to refine the process model and develop a dynamic framework and set of theoretical propositions that would underpin explanations of PPP success and legitimacy in matched contexts through analytical generalisation. The study found that PPP success was based on different models of collaboration and partner resource contribution that arose from a confluence of variables including the development of shared purpose, private voluntary control in corporate governance mechanisms and boundary spanning leadership. The study contributes a contextual theory that explains how PPPs work and a research agenda of ‘corporate governance as inspiration’ from a sociological perspective of ‘liquid modernity’. Recommendations for policy and management practice were developed.

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In many countries and sectors, public procurement is developing from a functional orientation to an effective socio-economic policy lever. There is a great interest among managers and academics to learn from other countries’ and other sectors’ change initiatives and how they dealt with the challenges they encountered. This text provides such learning opportunities, presenting case studies of public procurement, covering diverse nations, sectors and issues. The cases are combined with editorial commentary and contextualizing chapters to assist the student reader in understanding this complex topic. The text combines descriptions of cases of public procurement with cross case analysis to draw out the key dimensions to enable further examination of the central themes. Each case study concludes with three questions to aid its use as a teaching and training text. Edited by a team of internationally recognised experts in the field this innovative text illustrates the strategies and innovations within public procurement on a global scale and highlights common problems that all countries encounter. Public Procurement is vital reading for anyone with an interest in this topical area.

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Purpose – The purpose of the paper was to conduct an empirical investigation to explore the impact of project management maturity models (PMMMs) on improving project performance. Design/methodology/approach – The investigation used a cross-case analysis involving over 90 individuals in seven organisations. Findings – The findings of the empirical investigation indicate that PMMMs demonstrate very high levels of variability in individual's assessment of project management maturity. Furthermore, at higher levels of maturity, the type of performance improvement adopted following their application is related to the type of PMMM used in the assessment. The paradox of the unreliability of PMMMs and their widespread acceptance is resolved by calling upon the “wisdom of crowds” phenomenon which has implications for the use of maturity model assessments in other arena. Research limitations/implications – The investigation does have the usual issues associated with case research, but the steps that have been taken in the cross-case construction and analysis have improved the overall robustness and extendibility of the findings. Practical implications – The tendency for PMMMs to shape improvements based on their own inherent structure needs further understanding. Originality/value – The use of empirical methods to investigate the link between project maturity models and extant changes in project management performance is highly novel and the findings that result from this have added resonance.

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This thesis objective is to discover “How are informal decisions reached by screeners when filtering out undesirable job applications?” Grounded theory techniques were employed in the field to observe and analyse informal decisions at the source by screeners in three distinct empirical studies. Whilst grounded theory provided the method for case and cross-case analysis, literature from academic and non-academic sources was evaluated and integrated to strengthen this research and create a foundation for understanding informal decisions. As informal decisions in early hiring processes have been under researched, this thesis contributes to current knowledge in several ways. First, it locates the Cycle of Employment which enhances Robertson and Smith’s (1993) Selection Paradigm through the integration of stages that individuals occupy whilst seeking employment. Secondly, a general depiction of the Workflow of General Hiring Processes provides a template for practitioners to map and further develop their organisational processes. Finally, it highlights the emergence of the Locality Effect, which is a geographically driven heuristic and bias that can significantly impact recruitment and informal decisions. Although screeners make informal decisions using multiple variables, informal decisions are made in stages as evidence in the Cycle of Employment. Moreover, informal decisions can be erroneous as a result of a majority and minority influence, the weighting of information, the injection of inappropriate information and criteria, and the influence of an assessor. This thesis considers these faults and develops a basic framework of understanding informal decisions to which future research can be launched.