16 resultados para Post-structural
em Aston University Research Archive
Resumo:
Firms acting as suppliers to the British automotive industry have a long history of so doing, with some evidencing histories that predate even the invention of the motor car. In exploring the challenges faced by the descendants of these firms in the 1990s, a review is undertaken of the bodies of literature surrounding the changes wrought through the increased globalisation of the industry; the impact of new manufacturing technologies and techniques; the rising levels of co-operation between firms; and the growing impact of the automotive 'service sector'. Moreover, an exploration is undertaken of the perceived 'realities' of the automotive industry as constructed through discourse, including the ways in which discourse effects a continual reinterpretation and re-evaluation of the historical evolution of the industry. Attention is focused on the implications of the above for the automotive supply chain, and the means for its rationalisation proposed by the major car manufacturers and their partner-suppliers. Post-structuralist approaches are introduced as part of an attempt to establish and appropriate research methodology that can explore and deconstruct the discourses surrounding 'modernity', 'supply chain rationalisation', 'flexible specialisation' and 'globalisation' within the automotive industry. Analytical research is conducted into the small- to medium-sized business that constitute the majority of the supplier base in the United Kingdom, and the findings of this research are compared with those of a similar study conducted a quarter-century ago. In this way, the relationships of these firms with their customers, suppliers, and peers are investigated, as are their perceptions of a changing marketplace and their reactions to the impact of policies such as the 'supply chain rationalisation' pursued by the major automotive manufacturers. Authoritative discourses of industry form, function, and structure are challenged, with voice being granted to the marginalised: small suppliers, 'service sector' firms, or those only partly involved in the automotive industry.
Resumo:
Theoretical and empirical studies show that deindustrialisation, broadly observed in developed countries, is an inherent part of the economic development pattern. However, post-communist countries, while being only middle-income economies, have also experienced deindustrialisation. Building on the model developed by Rowthorn and Wells (1987) we explain this phenomenon and show that there is a strong negative relationship between the magnitude of deindustrialisation and the efficiency and consistency of market reforms. We also demonstrate that reforms of the agricultural sector play a significant role in placing a transition country on a development path that guarantees convergence to EU employment structures.
Resumo:
The aim of this paper is to model the evolution of employment structure in post-communist economies in the broader context of deindustrialisation. The paper builds on the model of structural change developed by Rowthorn and Wells (1987). We show that the starting point of high industry sector share in total employment and its direct fall when productivity of sectors changes in favour of services can be explained in terms of this framework. Moreover, the model can also describe the phenomenon of a further expansion of the agriculture, observed in countries classified as "less consistent" in the reforms implementation. Hence, we distinguish two development paths, the efficient one, called "horizontal", and the inefficient one called "vertical". We illustrate it with empirical data, using alternative measures of structural change and patterns of structural evolutions during transition. Finally, we discuss the link between the EBRD indicators of reforms and structural change. We show that the "quality" of reforms, not the initial GDP level determines a country's development path.
Resumo:
This article investigates the behaviour of exchange rates across different regimes for a post-Bretton Woods period. The exchange rate regime classification is based on the classification of Frankel et al. (2004) who condensed the 10 categories of exchange rate regimes reported by the International Monetary Fund (IMF) into three categories. Panel unitroot tests and panel cointegration are used to examine the Purchasing Power Parity (PPP) hypothesis. The latter test is used to check for both the weak and strong forms of PPP. The panel unit-root tests show no evidence of PPP and suggest there is no difference in the behaviour of exchange rates across different regimes. However, failure to detect PPP across any of the regimes could be due to structural breaks. This assumption is reinforced by the results of cointegration tests, which suggest that there exists at least a weak form of PPP for the different regimes. The evidence for strong PPP decreases as the exchange rate regime moves away from a flexible exchange rate regime.
Corruption in the post-Soviet workplace: the experiences of recent graduates in contemporary Ukraine
Resumo:
While Ukraine was bestowed market economy status by the European Union in 2005 its labour market still endures many structural problems. By exploring the experiences of young graduate employees this article highlights the difficultly in obtaining work within Ukraine's labour market and the problems they face once they have secured employment. Rather than seeing the development of a transparent labour market the collapse of the command economy has seen a relatively closed system develop. The article demonstrates how many jobs are secured through the use of connections or the demanding, and payment, of bribes.The situation does not improve once graduates obtain long-term employment. Interviewees discuss the lack of job security, the informal payment of wages and the lack of legal protection from corrupt employer practices. The article has broader resonance outside of the Ukrainian case study as the discussion of workplace corruption highlights how the issue is concerned with much more than simply cash based transactions and how those that endure it are likely to turn to the informal economy for employment.
Resumo:
This paper examines the sources of structural changes in output growth of South Africa's economy over 1975-93 using a decomposition method within the inputoutput (IO) framework for analysing output changes from a demand side perspective. It decomposes output growth into private consumption, government consumption, investment and export components and also measures the impact of import substitution and changes in intermediate input use (as indicated by changes in IO coefficients). It is found that, before 1981, overall output growth was multi-components driven with all the above components contributing positively to economic growth. However, the collapse of investment demand is by far the single largest factor contributing to the economic stagnation that categorizes the post-1981 period.
Resumo:
This paper examines how the loss of 6300 jobs from the closure of MG Rover (MGR) in the city of Birmingham (UK) in April 2005 affected the employment trajectories of ex-workers, in the context of wider structural change and efforts at urban renewal. The paper presents an analysis of a longitudinal survey of 300 ex-MGR workers, and examines to what extent the state of local labour markets and workers’ geographical mobility—as well as the effectiveness of the immediate policy response and longer-term local economic strategies—may have helped to balance the impacts of personal attributes associated with workers’ employability and their reabsorption into the labour markets. It is found that the relative buoyancy of the local economy, the success of longer-run efforts at diversification and a strong policy response and retraining initiative helped many disadvantaged workers to find new jobs in the medium term. However, the paper also highlights the unequal employment outcomes and trajectories that many lesser-skilled workers faced. It explores the policy issues arising from such closures and their aftermath, such as the need to co-ordinate responses, to retain institutional capacity, to offer high-quality training and education resources to workers and, where possible, to slow down such closure processes to enable skills to be retained and reused within the local economy.
Resumo:
The aim of this research is to promote the use of G.R.P. as a structural material. In the past, the use of G.R.P. has been confined to non-load carrying applications. Such uses are still rapidly increasing but in addition significant changes have been made during the last decade in the development of semi-structural and now even fully structural applications. Glass-reinforced plastic is characterized by a high strength but a relatively low modulus of elasticity. For this reasona G.R.P. structure can expect to show large deformations as a result of which the individual structural members will fail under load due to a loss of stability rather than approaching the ultimate strength of the material. For this reason the selection of the geometrical shapes of G.R.P. structural elements is considered to be an important factor in designing G.R.P. structures. The first chapter of this thesis deals with a general review of the theoretical and experimental methods used to describe the structural properties of G.R.P. The research programme includes five stages dealing with the structural behaviour of G.R.P. The first stage (Chapter 2) begins with selecting and designing an optimum box beam cross-section which gives the maximum flexural and torsional rigidity. The second stage of investigation (Chapter 3) deals with beam to beam connections. A joint was designed and manufactured with different types of fasteners used to connect two beam units. A suitable fastener was selected and the research extended to cover the behaviour of long span beams using multiple joints. The third part of the investigation includes a study of the behaviour of box beams subjected to combined bending, shear and torsion. A special torque rig was developed to perform the tests. Creep deformation of 6 m span G.R.P. was investigated as the fourth stage under a range of loading conditions. As a result of the phenomenon of post buckling behaviour exhibited in the compression flange during testing of box beams during earlier stages of the investigation it was decided to consider this phenomenon in more detail in the final stage of the investigation. G.R.P. plates with different fibre orientation were subjected to uniaxial compression and tested up to failure. In all stages of the investigation theoretical predictions and experimental results were compared and generally good correlation between theory and experimental data was observed.
Resumo:
This paper employs a Component GARCH in Mean model to show that house prices across a number of major US cities between 1987 and 2009 have displayed asset market properties in terms of both risk-return relationships and asymmetric adjustment to shocks. In addition, tests for structural breaks in the mean and variance indicate structural instability across the data range. Multiple breaks are identified across all cities, particularly for the early 1990s and during the post-2007 financial crisis as housing has become an increasingly risky asset. Estimating the models over the individual sub-samples suggests that over the last 20 years the financial sector has increasingly failed to account for the levels of risk associated with real estate markets. This result has possible implications for the way in which financial institutions should be regulated in the future.
Resumo:
Previous empirical assessments of the effectiveness of structural merger remedies have focused mainly on the subsequent viability of the divested assets. Here, we take a different approach by examining how competitive are the market structures which result from the divestments. We employ a tightly specified sample of markets in which the European Commission (EC) has imposed structural merger remedies. It has two key features: (i) it includes all mergers in which the EC appears to have seriously considered, simultaneously, the possibility of collective dominance, as well as single dominance; (ii) in a previous paper, for the same sample, we estimated a model which proved very successful in predicting the Commission’s merger decisions, in terms of the market shares of the leading firms. The former allows us to explore the choices between alternative theories of harm, and the latter provides a yardstick for evaluating whether markets are competitive or not – at least in the eyes of the Commission. Running the hypothetical post-remedy market shares through the model, we can predict whether the EC would have judged the markets concerned to be competitive, had they been the result of a merger rather than a remedy. We find that a significant proportion were not competitive in this sense. One explanation is that the EC has simply been inconsistent – using different criteria for assessing remedies from those for assessing the mergers in the first place. However, a more sympathetic – and in our opinion, more likely – explanation is that the Commission is severely constrained by the pre-merger market structures in many markets. We show that, typically, divestment remedies return the market to the same structure as existed before the proposed merger. Indeed, one can argue that any competition authority should never do more than this. Crucially, however, we find that this pre-merger structure is often itself not competitive. We also observe an analogous picture in a number of markets where the Commission chose not to intervene: while the post-merger structure was not competitive, nor was the pre-merger structure. In those cases, however, the Commission preferred the former to the latter. In effect, in both scenarios, the EC was faced with a no-win decision. This immediately raises a follow-up question: why did the EC intervene for some, but not for others – given that in all these cases, some sort of anticompetitive structure would prevail? We show that, in this sample at least, the answer is often tied to the prospective rank of the merged firm post-merger. In particular, in those markets where the merged firm would not be the largest post-merger, we find a reluctance to intervene even where the resulting market structure is likely to be conducive to collective dominance. We explain this by a willingness to tolerate an outcome which may be conducive to tacit collusion if the alternative is the possibility of an enhanced position of single dominance by the market leader. Finally, because the sample is confined to cases brought under the ‘old’ EC Merger Regulation, we go on to consider how, if at all, these conclusions require qualification following the 2004 revisions, which, amongst other things, made interventions for non-coordinated behaviour possible without requiring that the merged firm be a dominant market leader. Our main conclusions here are that the Commission appears to have been less inclined to intervene in general, but particularly for Collective Dominance (or ‘coordinated effects’ as it is now known in Europe as well as the US.) Moreover, perhaps contrary to expectation, where the merged firm is #2, the Commission has to date rarely made a unilateral effects decision and never made a coordinated effects decision.
Resumo:
It is generally believed that the structural reforms that were introduced in India following the macro-economic crisis of 1991 ushered in competition and forced companies to become more efficient. However, whether the post-1991 growth is an outcome of more efficient use of resources or greater use of factor inputs remains an open empirical question. In this paper, we use plant-level data from 1989–1990 and 2000–2001 to address this question. Our results indicate that while there was an increase in the productivity of factor inputs during the 1990s, most of the growth in value added is explained by growth in the use of factor inputs. We also find that median technical efficiency declined in all but one of the industries between 1989–1990 and 2000–2001, and that change in technical efficiency explains a very small proportion of the change in gross value added.
Resumo:
In this paper we present a simple three-sector model explaining the structural change in employment, which is a modified version of Rowthorn-Wells (1987). We supplement the theoretical analysis with simple econometric tests, which illustrate how the modified Rowthorn-Wells model can be used to (i) motivate empirical estimates of the link between the level of development and structures of employment, (ii) illustrate structural distortions under the command economies, and the structural adjustment that happened during the post-Communist transition. We demonstrate that in the case of these economies, the transition process leads to an adjustment to the employment structures predicted by the model.
Resumo:
Full text: The idea of producing proteins from recombinant DNA hatched almost half a century ago. In his PhD thesis, Peter Lobban foresaw the prospect of inserting foreign DNA (from any source, including mammalian cells) into the genome of a λ phage in order to detect and recover protein products from Escherichia coli [ 1 and 2]. Only a few years later, in 1977, Herbert Boyer and his colleagues succeeded in the first ever expression of a peptide-coding gene in E. coli — they produced recombinant somatostatin [ 3] followed shortly after by human insulin. The field has advanced enormously since those early days and today recombinant proteins have become indispensable in advancing research and development in all fields of the life sciences. Structural biology, in particular, has benefitted tremendously from recombinant protein biotechnology, and an overwhelming proportion of the entries in the Protein Data Bank (PDB) are based on heterologously expressed proteins. Nonetheless, synthesizing, purifying and stabilizing recombinant proteins can still be thoroughly challenging. For example, the soluble proteome is organized to a large part into multicomponent complexes (in humans often comprising ten or more subunits), posing critical challenges for recombinant production. A third of all proteins in cells are located in the membrane, and pose special challenges that require a more bespoke approach. Recent advances may now mean that even these most recalcitrant of proteins could become tenable structural biology targets on a more routine basis. In this special issue, we examine progress in key areas that suggests this is indeed the case. Our first contribution examines the importance of understanding quality control in the host cell during recombinant protein production, and pays particular attention to the synthesis of recombinant membrane proteins. A major challenge faced by any host cell factory is the balance it must strike between its own requirements for growth and the fact that its cellular machinery has essentially been hijacked by an expression construct. In this context, Bill and von der Haar examine emerging insights into the role of the dependent pathways of translation and protein folding in defining high-yielding recombinant membrane protein production experiments for the common prokaryotic and eukaryotic expression hosts. Rather than acting as isolated entities, many membrane proteins form complexes to carry out their functions. To understand their biological mechanisms, it is essential to study the molecular structure of the intact membrane protein assemblies. Recombinant production of membrane protein complexes is still a formidable, at times insurmountable, challenge. In these cases, extraction from natural sources is the only option to prepare samples for structural and functional studies. Zorman and co-workers, in our second contribution, provide an overview of recent advances in the production of multi-subunit membrane protein complexes and highlight recent achievements in membrane protein structural research brought about by state-of-the-art near-atomic resolution cryo-electron microscopy techniques. E. coli has been the dominant host cell for recombinant protein production. Nonetheless, eukaryotic expression systems, including yeasts, insect cells and mammalian cells, are increasingly gaining prominence in the field. The yeast species Pichia pastoris, is a well-established recombinant expression system for a number of applications, including the production of a range of different membrane proteins. Byrne reviews high-resolution structures that have been determined using this methylotroph as an expression host. Although it is not yet clear why P. pastoris is suited to producing such a wide range of membrane proteins, its ease of use and the availability of diverse tools that can be readily implemented in standard bioscience laboratories mean that it is likely to become an increasingly popular option in structural biology pipelines. The contribution by Columbus concludes the membrane protein section of this volume. In her overview of post-expression strategies, Columbus surveys the four most common biochemical approaches for the structural investigation of membrane proteins. Limited proteolysis has successfully aided structure determination of membrane proteins in many cases. Deglycosylation of membrane proteins following production and purification analysis has also facilitated membrane protein structure analysis. Moreover, chemical modifications, such as lysine methylation and cysteine alkylation, have proven their worth to facilitate crystallization of membrane proteins, as well as NMR investigations of membrane protein conformational sampling. Together these approaches have greatly facilitated the structure determination of more than 40 membrane proteins to date. It may be an advantage to produce a target protein in mammalian cells, especially if authentic post-translational modifications such as glycosylation are required for proper activity. Chinese Hamster Ovary (CHO) cells and Human Embryonic Kidney (HEK) 293 cell lines have emerged as excellent hosts for heterologous production. The generation of stable cell-lines is often an aspiration for synthesizing proteins expressed in mammalian cells, in particular if high volumetric yields are to be achieved. In his report, Buessow surveys recent structures of proteins produced using stable mammalian cells and summarizes both well-established and novel approaches to facilitate stable cell-line generation for structural biology applications. The ambition of many biologists is to observe a protein's structure in the native environment of the cell itself. Until recently, this seemed to be more of a dream than a reality. Advances in nuclear magnetic resonance (NMR) spectroscopy techniques, however, have now made possible the observation of mechanistic events at the molecular level of protein structure. Smith and colleagues, in an exciting contribution, review emerging ‘in-cell NMR’ techniques that demonstrate the potential to monitor biological activities by NMR in real time in native physiological environments. A current drawback of NMR as a structure determination tool derives from size limitations of the molecule under investigation and the structures of large proteins and their complexes are therefore typically intractable by NMR. A solution to this challenge is the use of selective isotope labeling of the target protein, which results in a marked reduction of the complexity of NMR spectra and allows dynamic processes even in very large proteins and even ribosomes to be investigated. Kerfah and co-workers introduce methyl-specific isotopic labeling as a molecular tool-box, and review its applications to the solution NMR analysis of large proteins. Tyagi and Lemke next examine single-molecule FRET and crosslinking following the co-translational incorporation of non-canonical amino acids (ncAAs); the goal here is to move beyond static snap-shots of proteins and their complexes and to observe them as dynamic entities. The encoding of ncAAs through codon-suppression technology allows biomolecules to be investigated with diverse structural biology methods. In their article, Tyagi and Lemke discuss these approaches and speculate on the design of improved host organisms for ‘integrative structural biology research’. Our volume concludes with two contributions that resolve particular bottlenecks in the protein structure determination pipeline. The contribution by Crepin and co-workers introduces the concept of polyproteins in contemporary structural biology. Polyproteins are widespread in nature. They represent long polypeptide chains in which individual smaller proteins with different biological function are covalently linked together. Highly specific proteases then tailor the polyprotein into its constituent proteins. Many viruses use polyproteins as a means of organizing their proteome. The concept of polyproteins has now been exploited successfully to produce hitherto inaccessible recombinant protein complexes. For instance, by means of a self-processing synthetic polyprotein, the influenza polymerase, a high-value drug target that had remained elusive for decades, has been produced, and its high-resolution structure determined. In the contribution by Desmyter and co-workers, a further, often imposing, bottleneck in high-resolution protein structure determination is addressed: The requirement to form stable three-dimensional crystal lattices that diffract incident X-ray radiation to high resolution. Nanobodies have proven to be uniquely useful as crystallization chaperones, to coax challenging targets into suitable crystal lattices. Desmyter and co-workers review the generation of nanobodies by immunization, and highlight the application of this powerful technology to the crystallography of important protein specimens including G protein-coupled receptors (GPCRs). Recombinant protein production has come a long way since Peter Lobban's hypothesis in the late 1960s, with recombinant proteins now a dominant force in structural biology. The contributions in this volume showcase an impressive array of inventive approaches that are being developed and implemented, ever increasing the scope of recombinant technology to facilitate the determination of elusive protein structures. Powerful new methods from synthetic biology are further accelerating progress. Structure determination is now reaching into the living cell with the ultimate goal of observing functional molecular architectures in action in their native physiological environment. We anticipate that even the most challenging protein assemblies will be tackled by recombinant technology in the near future.