Sarbanes-Oxley and the Need for Audit Committee Independence: Contrary Evidence in the Textile Industry

We investigate whether the appearance of audit committee independence, e.g., outside membership as defined by the Sarbanes-Oxley Act of 2002 (SOA), is necessarily related to effective independence, e.g., the audit committee’s support of an auditor’s going-concern opinion (Carcello and Neal 2003; 2000). The SOA makes the agency theory assumption, generally supported by current research, that seemingly non-independent audit committee members reduce the reliability of the financial reporting. Yet, prior to the SOA, other rulings permitted non-independent audit committee members to serve when it was “in the best interests of the firm,” and even the Carcello and Neal (2000) findings point to a possible industry or company-size effect in measuring audit committee effectiveness. It seems that manager-owner committee members of smaller companies may also do the right thing. Therefore, we reconsider this independence question for the textile industry, one severely stressed and possibly affected by firm size. We observe seventy-four companies during the years 2000 and 2001 when the SOA was not in effect to determine whether their non-dependent-appearing audit committees also would effectively act independent, without the constraint of the SOA. We do find at least two SOA non-independent characteristics of audit committees, what would be two apparent SOA violations in 2011, contrarily associated with two actions of effective independence. We do not find any one of the ten recommended SOA requirements correlated with these actions of effective independence. These findings suggest that measures of effective independence may not necessarily be related to appearance, and may instead depend on company or industry size, adding to the growing body of research that argues for restricting government financial regulation (Gao et al., 2009; Hayes, 2009; Hart, 2009; Dodd–Frank Wall Street Reform and Consumer Protection Act, 2010; Orol, 2011)

A Trapped Field of 17.6 T in Melt-Processed, Bulk Gd-Ba-Cu-O Reinforced with Shrink-Fit Steel

The ability of large grain, REBa$_{2}$Cu$_{3}$O$_{7-\delta}$ [(RE)BCO; RE = rare earth] bulk superconductors to trap magnetic field is determined by their critical current. With high trapped fields, however, bulk samples are subject to a relatively large Lorentz force, and their performance is limited primarily by their tensile strength. Consequently, sample reinforcement is the key to performance improvement in these technologically important materials. In this work, we report a trapped field of 17.6 T, the largest reported to date, in a stack of two, silver-doped GdBCO superconducting bulk samples, each of diameter 25 mm, fabricated by top-seeded melt growth (TSMG) and reinforced with shrink-fit stainless steel. This sample preparation technique has the advantage of being relatively straightforward and inexpensive to implement and offers the prospect of easy access to portable, high magnetic fields without any requirement for a sustaining current source.Comment: Updated submission to reflect licence change to CC-BY. This is the "author accepted manuscript" and is identical in content to the published versio

A systematic review of population based epidemiological studies in Myasthenia Gravis

<p>Abstract</p> <p>Background</p> <p>The aim was to collate all myasthenia gravis (MG) epidemiological studies including AChR MG and MuSK MG specific studies. To synthesize data on incidence rate (IR), prevalence rate (PR) and mortality rate (MR) of the condition and investigate the influence of environmental and technical factors on any trends or variation observed.</p> <p>Methods</p> <p>Studies were identified using multiple sources and meta-analysis performed to calculate pooled estimates for IR, PR and MR.</p> <p>Results</p> <p>55 studies performed between 1950 and 2007 were included, representing 1.7 billion population-years. For All MG estimated pooled IR (eIR): 5.3 per million person-years (C.I.:4.4, 6.1), range: 1.7 to 21.3; estimated pooled PR: 77.7 per million persons (C.I.:64.0, 94.3), range 15 to 179; MR range 0.1 to 0.9 per millions person-years. AChR MG eIR: 7.3 (C.I.:5.5, 7.8), range: 4.3 to 18.0; MuSK MG IR range: 0.1 to 0.32. However marked variation persisted between populations studied with similar methodology and in similar areas.</p> <p>Conclusions</p> <p>We report marked variation in observed frequencies of MG. We show evidence of increasing frequency of MG with year of study and improved study quality. This probably reflects improved case ascertainment. But other factors must also influence disease onset resulting in the observed variation in IR across geographically and genetically similar populations.</p

Ground state superconducting phase fluctuations as a precursor for strong critical fluctuations in high-T_c superconductors

We analyse the reversible magnetisation and heat capacity of YBa_2Cu_3O_7-δ in the "vortex liquid" state and find that both properties are reasonably well described by the 3D XY critical-fluctuation model. The free-energy density in the "vortex liquid" state has a particularly simple form over a wide range of fields (H) and temperatures (T). This leads us to a picture in which the presence of critical fluctuations in high-T_c superconductors is directly linked to the remarkably small number of overlapping Cooper pairs at T=0 and H=0 rather than low dimensionality or high temperatures

Distribution of the superconducting critical current density within a Gd–Ba–Cu–O single grain

Abstract: The magnitude of the maximum trapped magnetic field in a bulk, single-grain superconductor is a key performance figure of merit. This is determined, generally, by the magnitude of the critical current density, Jc, and the length scale over which it flows. As with all type-II superconductors, Jc is related closely to the microstructure of the superconducting material and, in the case of RE–Ba–Cu–O [(RE)BCO, where RE is a rare-earth element or yttrium] single grains, RE2BaCuO5 (RE-211) inclusions in the superconducting REBa2Cu3O7−δ (RE-123) phase matrix are key microstructural features that act effectively as flux pinning centres. Although the distribution of RE-211 in single-grain bulk superconductors has been studied extensively, the variation of Jc within a given sample has been much investigated much less thoroughly. A detailed experimental understanding of the variation of Jc in these technologically important materials, therefore, is required given the growing popularity and significance of numerical techniques for modelling the behaviour of type-II bulk superconductors. Here we report a systematic investigation of the correlation between Gd-211 particle density and sample porosity, which are microstructural features, and Tc and Jc in a Gd–Ba–Cu–O bulk, single grain fabricated using a buffer layer and a supply of additional liquid phase. This was performed by cutting the sample into numerous sub-specimens of approximate dimensions 1.8 × 2.8 × 1.5 mm3. We observe that Jc decreases with distance from the seed, although more strongly with distance along the c-axis than along the a–b plane. In contrast to what might be expected given the assumed contribution of RE-211 inclusions to flux pinning, we find no evidence of a clear correlation between the local RE-211 precipitate density and local critical current on a length scale of mm. We observe that the porosity of the sample is a more dominant factor in determining the distribution of Jc within a single grain

Flux jumps in ring-shaped and assembled bulk superconductors during pulsed field magnetization

Abstract: Bulk (RE)BCO, where RE is a rare-earth element or yttrium, superconductors fabricated in the form of rings are potentially useful for a variety of solenoidal-type applications, such as small, high field nuclear magnetic resonance and electromagnetic undulators. It is anticipated that the practical exploitation of these technologically important materials will involve pulse field magnetization (PFM) and, consequently, it is important to understand the behavior of ring-shaped samples subjected to the PFM process. Macroscopic flux jumps were observed in PFM experiments on ring-shaped bulk samples when the peak applied field reaches a threshold magnitude, similar to behavior reported previously in cylindrical samples. Magnetic flux jumps inward when the thermal instability is triggered, however it subsequently flows outwards from the sample, resulting in a relatively low trapped field. This behavior is attributed to a variety of effects, including the inhomogeneity of the material, which may lead to the formation of localized hot spots during the PFM process. In order to further elucidate this phenomena, the properties of a structure consisting of a bulk superconducting ring with a cylindrical superconductor core were studied. We observe that, although a flux jump occurs consistently in the ring, a critical state is established at the boundary of the ring-shaped sample and the core. We provide a detailed account of these experimental observations and provide an explanation in terms of the current understanding of the PFM process

Birds and Grazing Final Report

Southeastern Regional Sustainable Development Partnership

The growth and superconducting properties of RE–Ba–Cu–O single grains with combined RE elements (RE = Gd and Y)

Abstract: The superconducting properties, melting temperatures and crystal growth rates of single grain, RE–Ba–Cu–O [(RE)BCO] bulk superconductors (where RE = a rare earth element or yttrium) decrease with the RE-element sequence of Nd, Sm, Eu, Gd, Dy and Y. The mechanical properties of these technologically important materials, on the other hand, however, improve in the same sequence. Consequently, one promising approach for optimising the balance between mechanical and superconducting properties of bulk (RE)BCO superconductors, or for adjusting growth rate, is the use of combinations of different rare earth elements. In this study, we explore combinations of Gd and Y in the formation of (Gd–Y)–Ba–Cu–O single grains. We describe the optimisation of the growth process for this multi-RE element system and use optical and scanning electron microscopy to study the microstructure of both non-superconducting (Gd–Y)2BaCuO5 [(Y–Gd)-211] phase inclusions and the (Y–Gd)Ba2Cu3O7-δ [(Y–Gd)-123] phase matrix itself. We demonstrate that (Gd–Y)–Ba–Cu–O single grains can be fabricated reliably and that they exhibit reasonably good superconducting properties. We observe that there is an increase in RE-211 particle size in this mixed rare earth system, which, ultimately, limits sample performance, and conclude that this may be a general disadvantage of this approach to the synthesis of single grains for high field engineering applications