What drives security issuance decisions: Market timing, pecking order, or both?

We study market timing and pecking order in a sample of debt and equity issues and share repurchases of Canadian firms from 1998 to 2007. We find that only when firms are not financially constrained is there evidence that firms issue (repurchase) equity when their shares are overvalued (undervalued) and evidence that overvalued issuers earn lower postannouncement long-run returns. Similarly, we find that only when firms are not overvalued do they prefer debt to equity financing. These findings highlight an interaction between market timing and pecking order effects

Guidance on the Selection of Appropriate Indicators for Quantification of Antimicrobial Usage in Humans and Animals

An increasing variety of indicators of antimicrobial usage has become available in human and veterinary medicine, with no consensus on the most appropriate indicators to be used. The objective of this review is therefore to provide guidance on the selection of indicators, intended for those aiming to quantify antimicrobial usage based on sales, deliveries or reimbursement data. Depending on the study objective, different requirements apply to antimicrobial usage quantification in terms of resolution, comprehensiveness, stability over time, ability to assess exposure and comparability. If the aim is to monitor antimicrobial usage trends, it is crucial to use a robust quantification system that allows stability over time in terms of required data and provided output; to compare usage between different species or countries, comparability must be ensured between the different populations. If data are used for benchmarking, the system comprehensiveness is particularly crucial, while data collected to study the association between usage and resistance should express the exposure level and duration as a measurement of the exerted selection pressure. Antimicrobial usage is generally described as the number of technical units consumed normalized by the population at risk of being treated in a defined period. The technical units vary from number of packages to number of individuals treated daily by adding different levels of complexity such as daily dose or weight at treatment. These technical units are then related to a description of the population at risk, based either on biomass or number of individuals. Conventions and assumptions are needed for all of these calculation steps. However, there is a clear lack of standardization, resulting in poor transparency and comparability. By combining study requirements with available approaches to quantify antimicrobial usage, we provide suggestions on the most appropriate indicators and data sources to be used for a given study objective

The CI lines as tracers of molecular gas, and their prospects at high redshifts

We examine the fine structure lines $^{3}P_{1}\to$$^{3}P_{0}$ (492 GHz) and $^{3}P_2\to$$^{3}P_1$ (809 GHz) of neutral atomic carbon as bulk molecular gas mass tracers and find that they can be good and on many occasions better than $^{12}$CO transitions, especially at high redshifts. The notion of CI emission as an H$_2$ gas mass tracer challenges the long-held view of its distribution over only a relatively narrow layer in the CII/CI/CO transition zone in FUV-illuminated molecular clouds. Past observations have indeed consistently pointed towards a more extended CI distribution but it was only recently, with the advent of large scale imaging of its $^{3}P_{1}\to$$^{3}P_{0}$ transition, that its surprising ubiquity in molecular clouds has been fully revealed. In the present work we show that under {\it typical} ISM conditions such an ubiquity is inevitable because of well known dynamic and non-equilibrium chemistry processes maintaining a significant [C]/[$^{12}$CO] abundance throughout Giant Molecular Clouds during their lifetime. These processes are more intense in star-forming environments where a larger ambient cosmic ray flux will also play an important role in boosting [C]/[$^{12}$CO]. The resulting CI lines can be bright and effective H$_2$ mass tracers especially for diffuse ($\sim 10^2-10^3\rm cm^{-3}$) gas while in UV-intense and/or metal-poor environments their H$_2$-tracing capability diminishes because of large scale CII production but nevertheless remains superior to that of $^{12}$CO. The best place to take full advantage of CI's capacity to trace H$_2$ is not in the low-$z$ Universe, where large atmospheric absorption at 492 and 809 GHz precludes routine observations, but at high redshifts (\rm z\ga 1).Comment: Accepted for publication at the Monthly Notices of the Royal Astronomical Society (29 pages, 5 figures

Towards a quantum probability theory of similarity judgments

We review recent progress in understanding similarity judgments in cognition by means of quantum probability theory (QP) models. We begin by outlining some features of similarity judgments that have proven difficult to model by traditional approaches. We then briefly present a model of similarity judgments based on QP, and show how it can solve many of the problems faced by traditional approaches. Finally we look at some areas where the quantum model is currently less satisfactory, and discuss some open questions and areas for further work

Heritable patterns of tooth decay in the permanent dentition: Principal components and factor analyses

Background: Dental caries is the result of a complex interplay among environmental, behavioral, and genetic factors, with distinct patterns of decay likely due to specific etiologies. Therefore, global measures of decay, such as the DMFS index, may not be optimal for identifying risk factors that manifest as specific decay patterns, especially if the risk factors such as genetic susceptibility loci have small individual effects. We used two methods to extract patterns of decay from surface-level caries data in order to generate novel phenotypes with which to explore the genetic regulation of caries.Methods: The 128 tooth surfaces of the permanent dentition were scored as carious or not by intra-oral examination for 1,068 participants aged 18 to 75 years from 664 biological families. Principal components analysis (PCA) and factor analysis (FA), two methods of identifying underlying patterns without a priori surface classifications, were applied to our data.Results: The three strongest caries patterns identified by PCA recaptured variation represented by DMFS index (correlation, r = 0.97), pit and fissure surface caries (r = 0.95), and smooth surface caries (r = 0.89). However, together, these three patterns explained only 37% of the variability in the data, indicating that a priori caries measures are insufficient for fully quantifying caries variation. In comparison, the first pattern identified by FA was strongly correlated with pit and fissure surface caries (r = 0.81), but other identified patterns, including a second pattern representing caries of the maxillary incisors, were not representative of any previously defined caries indices. Some patterns identified by PCA and FA were heritable (h 2 = 30-65%, p = 0.043-0.006), whereas other patterns were not, indicating both genetic and non-genetic etiologies of individual decay patterns.Conclusions: This study demonstrates the use of decay patterns as novel phenotypes to assist in understanding the multifactorial nature of dental caries. © 2012 Shaffer et al; licensee BioMed Central Ltd

Quantifying antibiotic use in paediatrics: a proposal for neonatal DDDs

The defined daily dose (DDD) as defined by the World Health Organization (WHO) has been the most frequently used unit of measurement to measure antibiotic use. However, measuring antibiotic use in paediatrics is a problem as the WHO DDD methodology is not applicable in children (aged >1 month) due to the large variation in body weight within this population. Based on the narrow range of body weights in the neonatal population, we therefore aimed to develop a set of neonatal DDDs for antibiotics. Eight well-respected (inter)national sources for dosage recommendations of antibiotics in children and neonates were consulted for the assumed maintenance dose of the ten most frequently used antibiotics in neonatal intensive care units in its main indication for neonates. A set of neonatal DDDs for ten commonly used antibiotics in neonates based on an assumed neonatal weight of 2 kg was proposed. Primarily in children DDDs are not applicable to quantify antibiotic use since there is large variation in body weight. In the neonatal population, however, based on its narrow range of body weights and when access to patient level data is not available, neonatal DDDs can be used as a unit of measurement

Pharmacy sales data versus ward stock accounting for the surveillance of broad-spectrum antibiotic use in hospitals

<p>Abstract</p> <p>Background</p> <p>Antibiotic consumption in hospitals is commonly measured using the accumulated amount of drugs delivered from the pharmacy to ward held stocks. The reliability of this method, particularly the impact of the length of the registration periods, has not been evaluated and such evaluation was aim of the study.</p> <p>Methods</p> <p>During 26 weeks, we performed a weekly ward stock count of use of broad-spectrum antibiotics <b>- </b>that is second- and third-generation cephalosporins, carbapenems, and quinolones <b>- </b>in five hospital wards and compared the data with corresponding pharmacy sales figures during the same period. Defined daily doses (DDDs) for antibiotics were used as measurement units (WHO ATC/DDD classification). Consumption figures obtained with the two methods for different registration intervals were compared by use of intraclass correlation analysis and Bland-Altman statistics.</p> <p>Results</p> <p>Broad-spectrum antibiotics accounted for a quarter to one-fifth of all systemic antibiotics (ATC group J01) used in the hospital and varied between wards, from 12.8 DDDs per 100 bed days in a urological ward to 24.5 DDDs in a pulmonary diseases ward. For the entire study period of 26 weeks, the pharmacy and ward defined daily doses figures for all broad-spectrum antibiotics differed only by 0.2%; however, for single wards deviations varied from -4.3% to 6.9%. The intraclass correlation coefficient, pharmacy versus ward data, increased from 0.78 to 0.94 for parenteral broad-spectrum antibiotics with increasing registration periods (1-4 weeks), whereas the corresponding figures for oral broad-spectrum antibiotics (ciprofloxacin) were from 0.46 to 0.74. For all broad-spectrum antibiotics and for parenteral antibiotics, limits of agreement between the two methods showed, according to Bland-Altman statistics, a deviation of ± 5% or less from average mean DDDs at 3- and 4-weeks registration intervals. Corresponding deviation for oral antibiotics was ± 21% at a 4-weeks interval.</p> <p>Conclusions</p> <p>There is a need for caution in interpreting pharmacy sales data aggregated over short registration intervals, especially so for oral formulations. Even a one-month registration period may be too short.</p

Prolonged Visual Experience in Adulthood Modulates Holistic Face Perception

Background: Using the well-known composite illusion as a marker of the holistic perception of faces, we tested how prolonged visual experience with a specific population of faces (4- to 6-year-old children) modulates the face perception system in adulthood. Methodology/Principal Findings: We report a face composite effect that is larger for adult than children faces in a group of adults without experience with children faces (‘‘children-face novices’’), while it is of equal magnitude for adults and children faces in a population of preschool teachers (‘‘children-face experts’’). When considering preschool teachers only, we observed a significant correlation between the number of years of experience with children faces and the differential face composite effect between children and adults faces. Participants with at least 10 years of qualitative experience with children faces had a larger composite face effect for children than adult faces. Conclusions/Significance: Overall, these observations indicate that even in adulthood face processes can be reshaped qualitatively, presumably to facilitate efficient processing of the differential morphological features of the frequently encountered population of faces