Conditional volatility and firm size:an empirical analysis of UK equity portfolios

The techniques and insights from two distinct areas of financial economic modelling are combined to provide evidence of the influence of firm size on the volatility of stock portfolio returns. Portfolio returns are characterized by positive serial correlation induced by the varying levels of non-synchronous trading among the component stocks. This serial correlation is greatest for portfolios of small firms. The conditional volatility of stock returns has been shown to be well represented by the GARCH family of statistical processes. Using a GARCH model of the variance of capitalization-based portfolio returns, conditioned on the autocorrelation structure in the conditional mean, striking differences related to firm size are uncovered.

Influence of check and field size on the visual evoked magnetic response to a pattern shift stimulus

A decrease in the check size of a pattern shift stimulus increases the latency and amplitude of the visual evoked potential (VEP) P100. In addition, for a given check size, decreasing the size of the stimulus field increases the latency and amplitude of the P100. These results imply that the central regions of the retina make a significant contribution to the generation of the electrical P100. However, the corresponding magnetic P100m may have a different origin. We have studied the effects of check and field size on the P100m in five normal subjects using a DC-Squid, second-order gradiometer. Magnetic responses were recorded at the positive maximum of the P100m over the occipital scalp to six check sizes (10-100') presented in a large (13 degrees 34') and small (5 degrees 14') field and to a large check (100') presented in seven field sizes (1 degree 45' - 15 degrees 10'). No responses were recorded to any check size with a small field. Decreasing the check size presented in a large field increased latency of the P100m by approx. 30 ms while the amplitude of the response decreased with the largest reduction occurring between 70' and 12' checks. Using a large check, latency increased and amplitude decreased as the field size was reduced. The latency changes in response to check and field size were similar to those described for the VEP although the magnitudes of the magnetic changes were greater. Unlike the VEP, amplitude responses were maximal when large checks were presented in a large stimulus field. This suggests that regions outside the central retina make a more significant contribution to the visual evoked magnetic response than they do to the VEP, and that the P100m may be useful clinically in the study of diseases that affect the more peripheral regions of the retina.

Statnote 8: statistical power and sample size

Statistical software is now commonly available to calculate Power (P') and sample size (N) for most experimental designs. In many circumstances, however, sample size is constrained by lack of time, cost, and in research involving human subjects, the problems of recruiting suitable individuals. In addition, the calculation of N is often based on erroneous assumptions about variability and therefore such estimates are often inaccurate. At best, we would suggest that such calculations provide only a very rough guide of how to proceed in an experiment. Nevertheless, calculation of P' is very useful especially in experiments that have failed to detect a difference which the experimenter thought was present. We would recommend that P' should always be calculated in these circumstances to determine whether the experiment was actually too small to test null hypotheses adequately.

Computer aided design and manufacture of form-rolls

Cold roll forming of thin-walled sections is a very useful process in the sheet metal industry. However, the conventional method for the design and manufacture of form-rolls, the special tooling used in the cold roll forming process, is a very time consuming and skill demanding exercise. This thesis describes the establishment of a stand-alone minicomputer based CAD/CAM system for assisting the design and manufacture of form-rolls. The work was undertaken in collaboration with a leading manufacturer of thin-walled sections. A package of computer programs have been developed to provide computer aids for every aspect of work in form-roll design and manufacture. The programs have been successfully implemented, as an integrated CAD/CAM software system, on the ICL PERQ minicomputer with graphics facilities. Thus, the developed CAD/CAM system is a single-user workstation, with software facilities to help the user to perform the conventional roll design activities including the design of the finished section, the flower pattern, and the form-rolls. A roll editor program can then be used to modify, if required, the computer generated roll profiles. As far as manufacturing is concerned, a special-purpose roll machining program and postprocessor can be used in conjunction to generate the NC control part-programs for the production of form-rolls by NC turning. Graphics facilities have been incorporated into the CAD/CAM software programs to display drawings interactively on the computer screen throughout all stages of execution of the CAD/CAM software. It has been found that computerisation can shorten the lead time in all activities dealing with the design and manufacture of form-rolls, and small or medium size manufacturing companies can gain benefits from the CAD/CM! technology by developing, according to its own specification, a tailor-made CAD/CAM software system on a low cost minicomputer.

Product innovation in a medium size mature manufacturing company

This thesis is concerned with the management of product innovation inside the medium size, mature, manufacturing company. An academic perspective of innovation is integrated with an account of direct participation acquired over a two year period. The emergent synthesis provides fresh insight into some of the problems associated with producing and sustaining innovation. Product innovation is a very complex activity, and it presents particular difficulties for mature industry. However, the ability to innovate is fundamental to a company's continued survival. Three aspects of product innovation are examined in detail. Firstly, is the requirement to separate innovation activity from the on-going business interests; dependency between the degree of separation and novelty is supported. Secondly, a simple sequential model of the innovation process is tested and shown to be of considerable practical value. Thirdly a relationship is established between the age of the recipient market and the type of innovation to be found in that market All three aspects are found to have important implications for management in their pursuit of innovation. Management deficiencies which inhibited the successful resolution of innovation-linked problems are described and solutions which stress the need for commitment and coherency are proposed. The long existing management structure in the mature company which mitigates against successful and continuing innovation are examined in detail and a strategy is evolved which uses the intrinsic strengths of the mature company to promote innovation of a kind compatible with success in the market. A set of guidelines of practical value is presented for those managers wishing to pursue, and sustain, product innovation in the medium size mature company.

Purchasing in small firms – past assumptions, current evidence and future research

This paper reviews the literature on purchasing in small and medium sized enterprises (SMEs), in the context of the wider literature on SMEs. Evidence from these sources is related to insights from exploratory interviews with the owner-managers of 15 small firms, to derive recommendations for further research. Our findings complement those of Ellegaard (2006) but also extend these with specific proposals for the process and settings of future research, notably that the priority is to understand purchasing in small firms (cf medium or micro-firms) firms and research should be ‘small firm-centric’.

Bioactive glass sol-gel foam scaffolds:evolution of nanoporosity during processing and in situ monitoring of apatite layer formation using small- and wide-angle X-ray scattering

Recent work has highlighted the potential of sol-gel-derived calcium silicate glasses for the regeneration or replacement of damaged bone tissue. The work presented herein provides new insight into the processing of bioactive calcia-silica sol-gel foams, and the reaction mechanisms associated with them when immersed in vitro in a simulated body fluid (SBF). Small-angle X-ray scattering and wide-angle X-ray scattering (diffraction) have been used to study the stabilization of these foams via heat treatment, with analogous in situ time-resolved data being gathered for a foam immersed in SBF. During thermal processing, pore sizes have been identified in the range of 16.5-62.0 nm and are only present once foams have been heated to 400 degrees C and above. Calcium nitrate crystallites were present until foams were heated to 600 degrees C; the crystallite size varied from 75 to 145 nm and increased in size with heat treatment up to 300 degrees C, then decreased in size down to 95 rim at 400 degrees C. The in situ time-resolved data show that the average pore diameter decreases as a function of immersion time in SBF, as calcium phosphates grow on the glass surfaces. Over the same time, Bragg peaks indicative of tricalcium phosphate were evident after only 1-h immersion time, and later, hydroxycarbonate apatite was also seen. The hydroxycarbonate apatite appears to have preferred orientation in the (h,k,0) direction.

SMEs in a globalised world:survival and growth strategies on Europe's geographical periphery

This insightful book shows how small and medium enterprises (SMEs) from some of the traditionally less dynamic peripheral economies of the 'old' EU - namely Ireland, Italy, Portugal and Spain - have responded to the twin challenges of globalisation and industrial restructuring. Through a series of unique case studies the contributing authors discuss how these economies, and in particular the SME sector, can be transformed. The book begins by examining the key drivers of the globally competitive SME sector in the EU, before moving on to explore the relationship between multinational enterprises (MNEs), SMEs and industrial development. The authors investigate important policy implications and provide lessons for SME development and growth. With empirical and theoretical contributions on SMEs in both the manufacturing and the services sectors, this essential book will be invaluable for researchers and policymakers in small business economics and management. Postgraduate students of entrepreneurship, business economics, industrial economics and European studies will appreciate this unique set of insights.

Source of finance, growth and firm size:evidence from China

Using a comprehensive firm-level dataset spanning the period 1998-2005, this paper provides a thorough investigation of the relationship between firm size, total factor productivity growth and financial structure in China, controlling for the endogeneity of the latter. Generally, it finds financing source matters for firms of different size, and the extent to which financing source matters for firm growth is greater for small firms than big firms. Self-raised finance appears to be most effective in promoting small firms to grow, and bank loan seems to be more supportive to big firms. The relationship between size, finance and growth also depends on ownership. In addition, there exist strong complementarities between formal and informal finance, as well as between indigenous and foreign finance.

Entrepreneurship in Russia

This paper presents an account of the environment faced by entrepreneurs in Russia. In section one we give a brief introduction to the country which is followed by the overview of a public policy on small and medium enterprises in the next section. The current state of SMEs and some particularities of the entrepreneurial environment are discussed in section three, whereas section four focuses on the prospects of internationalisation of Russian SMEs. In section five we draw some conclusions.

Creating resilient SMEs:why one size might not fit all

This article is a first step towards addressing a gap in the field of organisational resilience research by examining how small and medium enterprises (SME) manage the threat and actuality of extreme events. Pilot research found that the managerial framing of extreme events varied by a range of organisational factors. This finding informed further examination of the contextual nature of the resilience concept. To date, large organisations have been the traditional focus of empirical work and theorising in this area; yet the heterogeneous SME sector makes up approximately 99% of UK industry and routinely operates under conditions of uncertainty. In a comparative study examining UK organisational resilience, it emerged that SME participants had both a distinctive perspective and approach to resilience when compared to participants from larger organisations. This article presents a subset of data from 11 SME decision-makers. The relationship between resilience capabilities, such as flexibility and adaptation, is interrogated in relation to organisational size. The data suggest limitations of applying a one-size-fits-all organisation solution (managerial or policy) to creating resilience. This study forms the basis for survey work examining the extent to which resilience is an organisationally contingent concept in practice.

The implications of internet auctions for small to medium sized enterprises (SMEs) in Great Britain

DUE TO COPYRIGHT RESTRICTIONS ONLY AVAILABLE FOR CONSULTATION AT ASTON UNIVERSITY LIBRARY AND INFORMATION SERVICES WITH PRIOR ARRANGEMENT

Purchasing green transport and logistics services:implications for small business

Considering its strong environmental impact, logistics plays a critical role in green supply chain management. It provides strategic links in the supply chain and is an essential function in the delivery of green products to the consumer. There is a general consensus on the fact that more environmentally sustainable companies may be achieved only if transport and logistics activities also become greener. To achieve this objective, buyer companies need to incorporate green considerations in the purchasing of transport and logistics services. This appears particularly challenging for small and medium sized enterprises (SMEs) because of their traditional lack of managerial, organisational and financial resources that often result in failure to adopt an environmental perspective. In the extant literature, green purchasing has received increased attention over the past decade and the strategic importance of introducing green aspects into purchasing practices has been recognised. However, little has been written in relation to purchasing green transport and logistics services. The aim of this paper is to explore practices in the buying of green transport and logistics services and to derive implications for small buyer companies. The paper analyses how general environmental company ambitions and environmental purchasing practices are reflected when green transport and logistics services are purchased in three different European countries (Italy, Ireland and Sweden) using a multiple case study research approach. The results of the paper indicate that while the case companies show a relatively high concern for green issues at corporate level, a lower importance is attributed to green issues at the purchasing function level. When green concerns in the purchasing of transport and logistics services are analysed the level of importance decreases further. Thus, a conflicting attitude is evident between the overall corporate level and the purchasing of transport and logistics services specifically. This suggests that there is potential for improvement especially in the area of green collaboration in buyer and supplier relationships.

Dynamic measurement of accommodation and pupil size using the portable Grand Seiko FR-5000 autorefractor

PURPOSE. The purpose of this study was to evaluate the potential of the portable Grand Seiko FR-5000 autorefractor to allow objective, continuous, open-field measurement of accommodation and pupil size for the investigation of the visual response to real-world environments and changes in the optical components of the eye. METHODS. The FR-5000 projects a pair of infrared horizontal and vertical lines on either side of fixation, analyzing the separation of the bars in the reflected image. The measurement bars were turned on permanently and the video output of the FR-5000 fed into a PC for real-time analysis. The calibration between infrared bar separation and the refractive error was assessed over a range of 10.0 D with a model eye. Tolerance to longitudinal instrument head shift was investigated over a ±15 mm range and to eye alignment away from the visual axis over eccentricities up to 25.0°. The minimum pupil size for measurement was determined with a model eye. RESULTS. The separation of the measurement bars changed linearly (r = 0.99), allowing continuous online analysis of the refractive state at 60 Hz temporal and approximately 0.01 D system resolution with pupils >2 mm. The pupil edge could be analyzed on the diagonal axes at the same rate with a system resolution of approximately 0.05 mm. The measurement of accommodation and pupil size were affected by eccentricity of viewing and instrument focusing inaccuracies. CONCLUSIONS. The small size of the instrument together with its resolution and temporal properties and ability to measure through a 2 mm pupil make it useful for the measurement of dynamic accommodation and pupil responses in confined environments, although good eye alignment is important. Copyright © 2006 American Academy of Optometry.