120 research outputs found

    The Impact of Sarbanes-Oxley Changes and Board Independence Power on Selected Governance Practices at the Board Level

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    The Sarbanes-Oxley Act (SOX) and related stock listing requirements now require boards of publicly traded companies to have a majority of outside, independent directors to provide a counterbalance to the power of management on the board. SOX also mandated the existence of three board committees, audit, nominating, and compensation which had to be comprised solely of independent directors. Using a sample of 335 firms and 3,675 observations from the S&P 500 from 1999 to 2009, I use panel Poisson regressions in pre-SOX (1999-2003) and post-SOX (2004-2009) periods to test the effect of SOX structural changes at the board and committee levels on governance practices as measured by the Entrenchment Index. I first consider the direct relationships, suggesting positive relationships between the mandated requirements of board independence, the presence of audit, nominating and compensation committees, and the independence of these committees on governance practices supporting shareholder value at the board level in the pre- and post-SOX periods. In the pre-SOX period I find significant relationships between board independence and governance practices as well as significant relationships between the existence of audit, nominating, and compensation committees and governance practices; however, they were not in the direction hypothesized. I find no significant relationships in the post-SOX period. I then create a new construct, board independence power (comprised of dimensions of structure/prestige, ownership and expertise) to measure the latent power of the independent members of the board. I validate the construct quantitatively through a factor analysis and interviews with board members and lawyers specializing in corporate governance. I hypothesize that board independence power positively moderates the relationship between the SOX structural changes and selected governance practices supporting shareholder value at the board level. In the pre and post-SOX periods, board independence structure/prestige power significantly moderates the relationship between the existence of the mandated committees and selected governance practices supporting shareholder value when they were lagged for one and two time periods. Results of this study demonstrate that the SOX structural changes by themselves have not led to better governance practices by boards. This is important given the organizational attention, energy and cost necessary to fulfill the SOX requirements

    A Persistent Simulation Environment for Autonomous Systems

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    The age of Autonomous Unmanned Aircraft Systems (AUAS) is creating new challenges for the accreditation and certification requiring new standards, policies and procedures that sanction whether a UAS is safe to fly. Establishing a basis for certification of autonomous systems via research into trust and trustworthiness is the focus of Autonomy Teaming and TRAjectories for Complex Trusted Operational Reliability (ATTRACTOR), a new NASA Convergent Aeronautics Solution (CAS) project. Simulation Environments to test and evaluate AUAS decision making may be a low-cost solution to help certify that various AUAS systems are trustworthy enough to be allowed to fly in current general and commercial aviation airspace. NASA is working to build a peer-to-peer persistent simulation (P3 Sim) environment. The P3 Sim will be a Massively Multiplayer Online (MMO) environment were AUAS avatars can interact with a complex dynamic environment and each other. The focus of the effort is to provide AUAS researchers a low-cost intuitive testing environment that will aid training for and assessment of decisions made by autonomous systems such as AUAS. This presentation focuses on the design approach and challenges faced in development of the P3 Sim Environment is support of investigating trustworthiness of autonomous systems

    The Relational Effect Of The Rule Of Law: A Comparative Study Of Japanese And South Korean Foreign Direct Investment

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    Building on institutional theory, this paper examines the relationship between the relative rule of law of home and host countries, the home country's institutional frame and foreign direct investment (FDI). We suggest that firms based in countries with a higher level of rule of law will invest more FDI per capita in host countries with comparable or higher levels of legal protections. Further, companies based in countries with a lower rule of law are accustomed to lower degrees of institutional safeguards. For these latter countries, the comparable levels of rule of law between home and host country will not as strongly impact FDI per capita. We test our logic through an examination of FDI from two home countries with different levels of rule of law: Japan (high) and South Korea (medium). Using FDI data from Japanese firms in 114 countries and South Korean firms in 118 countries, we find that while rule of law is a predictor of FDI per capita, the relative nature of the rule of law between home and host countries in higher rule of law home countries is also important. In addition, we discover that companies from Japan, a high rule of law country do seek out similar or higher rule of law environments for higher levels of FDI per capita investments while companies from a medium level rule of law country, South Korea, are less beholden to institutional standards. Our study contributes to the literature looking at the impact of country-level factors on foreign investment decisions, suggesting that it is the comparative rather than absolute values that are important to understand as well as the institutional environment in the home countr

    Acute maternal infection and risk of pre-eclampsia: a population-based case-control study.

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    BACKGROUND: Infection in pregnancy may be involved in the aetiology of pre-eclampsia. However, a clear association between acute maternal infection and pre-eclampsia has not been established. We assessed whether acute urinary tract infection, respiratory tract infection, and antibiotic drug prescriptions in pregnancy (a likely proxy for maternal infection) are associated with an increased risk of pre-eclampsia. METHODS AND FINDINGS: We used a matched nested case-control design and data from the UK General Practice Research Database to examine the association between maternal infection and pre-eclampsia. Primiparous women aged at least 13 years and registered with a participating practice between January 1987 and October 2007 were eligible for inclusion. We selected all cases of pre-eclampsia and a random sample of primiparous women without pre-eclampsia (controls). Cases (n=1533) were individually matched with up to ten controls (n=14236) on practice and year of delivery. We calculated odds ratios and 95% confidence intervals for pre-eclampsia comparing women exposed and unexposed to infection using multivariable conditional logistic regression. After adjusting for maternal age, pre-gestational hypertension, diabetes, renal disease and multifetal gestation, the odds of pre-eclampsia were increased in women prescribed antibiotic drugs (adjusted odds ratio 1.28;1.14-1.44) and in women with urinary tract infection (adjusted odds ratio 1.22;1.03-1.45). We found no association with maternal respiratory tract infection (adjusted odds ratio 0.91;0.72-1.16). Further adjustment for maternal smoking and pre-pregnancy body mass index made no difference to our findings. CONCLUSIONS: Women who acquire a urinary infection during pregnancy, but not those who have a respiratory infection, are at an increased risk of pre-eclampsia. Maternal antibiotic prescriptions are also associated with an increased risk. Further research is required to elucidate the underlying mechanism of this association and to determine whether, among women who acquire infections in pregnancy, prompt treatment or prophylaxis against infection might reduce the risk of pre-eclampsia

    Costs and effects of screening and treating low risk women with a singleton pregnancy for asymptomatic bacteriuria, the ASB study

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    <p>Abstract</p> <p>Background</p> <p>The prevalence of asymptomatic bacteriuria (ASB) in pregnancy is 2-10% and is associated with both maternal and neonatal adverse outcomes as pyelonephritis and preterm delivery. Antibiotic treatment is reported to decrease these adverse outcomes although the existing evidence is of poor quality.</p> <p>Methods/Design</p> <p>We plan a combined screen and treat study in women with a singleton pregnancy. We will screen women between 16 and 22 weeks of gestation for ASB using the urine dipslide technique. The dipslide is considered positive when colony concentration ≥10<sup>5</sup> colony forming units (CFU)/mL of a single microorganism or two different colonies but one ≥10<sup>5</sup> CFU/mL is found, or when Group B Streptococcus bacteriuria is found in any colony concentration. Women with a positive dipslide will be randomly allocated to receive nitrofurantoin or placebo 100 mg twice a day for 5 consecutive days (double blind). Primary outcomes of this trial are maternal pyelonephritis and/or preterm delivery before 34 weeks. Secondary outcomes are neonatal and maternal morbidity, neonatal weight, time to delivery, preterm delivery rate before 32 and 37 weeks, days of admission in neonatal intensive care unit, maternal admission days and costs.</p> <p>Discussion</p> <p>This trial will provide evidence for the benefit and cost-effectiveness of dipslide screening for ASB among low risk women at 16–22 weeks of pregnancy and subsequent nitrofurantoin treatment.</p> <p>Trial registration</p> <p>Dutch trial registry: NTR-3068</p

    Bacterial Toxicity of Potassium Tellurite: Unveiling an Ancient Enigma

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    Biochemical, genetic, enzymatic and molecular approaches were used to demonstrate, for the first time, that tellurite (TeO(3) (2−)) toxicity in E. coli involves superoxide formation. This radical is derived, at least in part, from enzymatic TeO(3) (2−) reduction. This conclusion is supported by the following observations made in K(2)TeO(3)-treated E. coli BW25113: i) induction of the ibpA gene encoding for the small heat shock protein IbpA, which has been associated with resistance to superoxide, ii) increase of cytoplasmic reactive oxygen species (ROS) as determined with ROS-specific probe 2′7′-dichlorodihydrofluorescein diacetate (H(2)DCFDA), iii) increase of carbonyl content in cellular proteins, iv) increase in the generation of thiobarbituric acid-reactive substances (TBARs), v) inactivation of oxidative stress-sensitive [Fe-S] enzymes such as aconitase, vi) increase of superoxide dismutase (SOD) activity, vii) increase of sodA, sodB and soxS mRNA transcription, and viii) generation of superoxide radical during in vitro enzymatic reduction of potassium tellurite

    A reexamination of information theory-based methods for DNA-binding site identification

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    <p>Abstract</p> <p>Background</p> <p>Searching for transcription factor binding sites in genome sequences is still an open problem in bioinformatics. Despite substantial progress, search methods based on information theory remain a standard in the field, even though the full validity of their underlying assumptions has only been tested in artificial settings. Here we use newly available data on transcription factors from different bacterial genomes to make a more thorough assessment of information theory-based search methods.</p> <p>Results</p> <p>Our results reveal that conventional benchmarking against artificial sequence data leads frequently to overestimation of search efficiency. In addition, we find that sequence information by itself is often inadequate and therefore must be complemented by other cues, such as curvature, in real genomes. Furthermore, results on skewed genomes show that methods integrating skew information, such as <it>Relative Entropy</it>, are not effective because their assumptions may not hold in real genomes. The evidence suggests that binding sites tend to evolve towards genomic skew, rather than against it, and to maintain their information content through increased conservation. Based on these results, we identify several misconceptions on information theory as applied to binding sites, such as negative entropy, and we propose a revised paradigm to explain the observed results.</p> <p>Conclusion</p> <p>We conclude that, among information theory-based methods, the most unassuming search methods perform, on average, better than any other alternatives, since heuristic corrections to these methods are prone to fail when working on real data. A reexamination of information content in binding sites reveals that information content is a compound measure of search and binding affinity requirements, a fact that has important repercussions for our understanding of binding site evolution.</p

    Cellular processes of v-Src transformation revealed by gene profiling of primary cells - Implications for human cancer

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    <p>Abstract</p> <p>Background</p> <p>Cell transformation by the Src tyrosine kinase is characterized by extensive changes in gene expression. In this study, we took advantage of several strains of the Rous sarcoma virus (RSV) to characterize the patterns of v-Src-dependent gene expression in two different primary cell types, namely chicken embryo fibroblasts (CEF) and chicken neuroretinal (CNR) cells. We identified a common set of v-Src regulated genes and assessed if their expression is associated with disease-free survival using several independent human tumor data sets.</p> <p>Methods</p> <p>CEF and CNR cells were infected with transforming, non-transforming, and temperature sensitive mutants of RSV to identify the patterns of gene expression in response to v-Src-transformation. Microarray analysis was used to measure changes in gene expression and to define a common set of v-Src regulated genes (CSR genes) in CEF and CNR cells. A clustering enrichment regime using the CSR genes and two independent breast tumor data-sets was used to identify a 42-gene aggressive tumor gene signature. The aggressive gene signature was tested for its prognostic value by conducting survival analyses on six additional tumor data sets.</p> <p>Results</p> <p>The analysis of CEF and CNR cells revealed that cell transformation by v-Src alters the expression of 6% of the protein coding genes of the genome. A common set of 175 v-Src regulated genes (CSR genes) was regulated in both CEF and CNR cells. Within the CSR gene set, a group of 42 v-Src inducible genes was associated with reduced disease- and metastasis-free survival in several independent patient cohorts with breast or lung cancer. Gene classes represented within this group include DNA replication, cell cycle, the DNA damage and stress responses, and blood vessel morphogenesis.</p> <p>Conclusion</p> <p>By studying the v-Src-dependent changes in gene expression in two types of primary cells, we identified a set of 42 inducible genes associated with poor prognosis in breast and lung cancer. The identification of these genes provides a set of biomarkers of aggressive tumor behavior and a framework for the study of cancer cells characterized by elevated Src kinase activity.</p
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