Satisfiability and Evolution

We show that, if truth assignments on $n$ variables reproduce through recombination so that satisfaction of a particular Boolean function confers a small evolutionary advantage, then a polynomially large population over polynomially many generations (polynomial in $n$ and the inverse of the initial satisfaction probability) will end up almost certainly consisting exclusively of satisfying truth assignments. We argue that this theorem sheds light on the problem of novelty in Evolution

The New Form 8-K Disclosures

The Securities and Exchange Commission (SEC) has mandated new disclosure requirements in Form 8-K, which became effective on August 23, 2004. The SEC expanded the list of items that have to be reported and accelerated the timeliness of these reports. This study examines the market reactions to 8-Ks filed under the new SEC regime and investigates whether periodic reports (10-K/Qs) are less informative under the new 8-K disclosure rules than previously. We observe that the newly required 8-K items constitute over half of all filings and that most firms disclose the required items within the new shortened period (four business days). We find that all disclosed items (old and new) are associated with abnormal volume and return volatility around both the event and the SEC filing dates, but also that some items have significant return drifts after the SEC filings. We find that the information content of periodic reports is not diminished by the more expansive and timely 8-K disclosures under the new guidance, suggesting that investors still use them to interpret the possible effects of material events that occurred earlier. We also find that good news reported in Forms 8-K generate greater market reactions on the event date than bad news, likely because of earlier public disclosure of good news by management

Is time spent on deployment a stronger predictor of insomnia than time spent in service?

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Non-cystic fibrosis bronchiectasis: review and recent advances

Bronchiectasis is an abnormal dilatation of bronchi and bronchioles associated with repeated cycles of airway infection and inflammation. This review will focus on non-cystic fibrosis bronchiectasis in children, with regard to etiology, diagnosis, treatment options, and recent advances

The High-Volume Return Premium and Post-Earnings Announcement Drift

This paper investigates the relationship among trading volume around earnings announcements, earnings forecast errors, and subsequent returns. Prior research finds a positive relation between earnings announcement period trading volume and subsequent returns (the high-volume return premium) and between earnings forecast errors and subsequent returns (post-earnings announcement drift). We find that for a sample of firms followed by analysts these effects are complementary, i.e., each retains incremental ability to predict post-earnings announcement returns. Prior research provides two competing explanations for the high-volume return premium: changes in firm visibility versus differences in risk. We provide evidence that seems to rule out risk-based explanations while supporting the visibility hypothesis

The Impact of Earnings on the Pricing of Credit Default Swaps

This study evaluates the impact of earnings on firm credit risk as captured by Credit Default Swaps (CDS). We find that earnings (changes) are negatively correlated with one-year swap premia (changes) after controlling for equity returns but not with longer term premia (changes). We also find that earnings surprises are significantly correlated with one-year CDS premia changes in the short window surrounding preliminary earnings dates and that absolute earnings surprises are significantly correlated with absolute one-year CDS premia changes in the short window surrounding SEC filing dates. These results suggest that high earnings convey favorable information about the short-term default risk of firms but not about the long term default risk. We further document that accruals/cash flow information conveyed by SEC filings provides information about long-term credit risk. Furthermore, the empirical results are consistent with structural and hybrid model-driven implications of CDS pricing

Improving Safety-Critical Systems by Visual Analysis

The importance analysis provides a means of analyzing the contribution of potential low-level system failures to identify and assess vulnerabilities of safety-critical systems. Common approaches attempt to enhance the system safety by addressing vulnerabilities using an iterative analysis process, while considering relevant constraints, e.g., cost, for optimizing the improvements. Typically, data regarding the analysis process is presented across several views with few interactive associations among them. Consequently, this hampers the identification of meaningful information supporting the decision making process. In this paper, we propose a visualization system that visually supports engineers in identifying proper solutions. The visualization integrates a decision tree with a plot representing the cause-effect relationship between the improvement ideas of vulnerabilities and the resulting risk reduction of system. Associating a component fault tree view with the plot allows to maintain helpful context information. The introduced visualization approach enables system and safety engineers to identify and analyze optimal solutions facilitating the improvement of the overall system safety