Decline in effectiveness of antenatal corticosteroids with time to birth : real or artefact?

The effectiveness of antenatal corticosteroids to prevent neonatal lung disease in women at risk of preterm birth was established by systematic reviews. In addition, subgroup analyses suggested that treatment was most effective in babies born one to seven days after administration. This belief led to widespread use of repeated courses of corticosteroids in women who did not deliver within a week or two of initial treatment. However, the notion that effectiveness declines after seven days may be incorrect, as the analyses that it is based on are unreliable. Here, we discuss the methodological problems of these analyses and their relevance to current randomised controlled trials of repeated versus single courses

Comments on 'Evolutionary neural network modelling for software cumulative failure time prediction' by Liang Tian and Afzel Noore [Reliability Engineering and System Safety 87 (2005) 45-51]

This paper [Tian L, Noore A. Evolutionary neural network modelling for software cumulative failure time prediction. Reliab Eng Syst Saf 2005; 87:45–51] purports to present a useful means of predicting the cumulative failure time function for software reliability growth. In fact, the nature of the ‘prediction’ is too simplistic to be of use. Furthermore, the authors' claims for the accuracy of the predictions appear to be without value

Discrete and continuous character-based disparity analyses converge to the same macroevolutionary signa. A case study from captorhinids

The relationship between diversity and disparity during the evolutionary history of a clade provides unique insights into evolutionary radiations and the biological response to bottlenecks and to extinctions. Here we present the first comprehensive comparison of diversity and disparity of captorhinids, a group of basal amniotes that is important for understanding the early evolution of high-fiber herbivory. A new fully resolved phylogeny is presented, obtained by the inclusion of 31 morphometric characters. The new dataset is used to calculate diversity and disparity through the evolutionary history of the clade, using both discrete and continuous characters. Captorhinids do not show a decoupling between diversity and disparity, and are characterized by a rather symmetric disparity distribution, with a peak in occupied morphospace at about the midpoint of the clade’s evolutionary history (Kungurian). This peak represents a delayed adaptive radiation, identified by the first appearance of several high-fiber herbivores in the clade, along with numerous omnivorous taxa. The discrete characters and continuous morphometric characters indicate the same disparity trends. Therefore, we argue that in the absence of one of these two possible proxies, the disparity obtained from just one source can be considered robust and representative of a general disparity pattern

Time evolution of spin state of radical ion pair in microwave field: An analytical solution

The paper reports an exact solution for the problem of spin evolution of radical ion pair in static magnetic and resonant microwave field taking into account Zeeman and hyperfine interactions and spin relaxation. The values of parameters that provide one of the four possible types of solution are analysed. It is demonstrated that in the absence of spin relaxation, besides the zero field invariant an invariant at large amplitudes of the resonant microwave field can be found. The two invariants open the possibility for simple calculation of microwave pulses to control quantum state of the radical pair. The effect of relaxation on the invariants is analysed and it is shown that changes in the high field invariant are induced by phase relaxation.Comment: 18 pages, 7 figure

Understanding hydrogen recombination line observations with ALMA and EVLA

Hydrogen recombination lines are one of the major diagnostics of H II region physical properties and kinematics. In the near future, the Expanded Very Large Array (EVLA) and the Atacama Large Millimeter Array (ALMA) will allow observers to study recombination lines in the radio and sub-mm regime in unprecedented detail. In this paper, we study the properties of recombination lines, in particular at ALMA wavelengths. We find that such lines will lie in almost every wideband ALMA setup and that the line emission will be equally detectable in all bands. Furthermore, we present our implementation of hydrogen recombination lines in the adaptive-mesh radiative transfer code RADMC-3D. We particularly emphasize the importance of non-LTE (local thermodynamical equilibrium) modeling since non-LTE effects can drastically affect the line shapes and produce asymmetric line profiles from radially symmetric H II regions. We demonstrate how these non-LTE effects can be used as a probe of systematic motions (infall & outflow) in the gas. We use RADMC-3D to produce synthetic observations of model H II regions and study the necessary conditions for observing such asymmetric line profiles with ALMA and EVLA.Comment: MNRAS in pres

Underpricing, underperformance and overreaction in initial public offerings : evidence from investor attention using online searches

Online activity of Internet users has proven very useful in modeling various phenomena across a wide range of scientific disciplines. In our study, we focus on two stylized facts or puzzles surrounding the initial public offerings (IPOs) - the underpricing and the long-term underperformance. Using the Internet searches on Google, we proxy the investor attention before and during the day of the offering to show that the high attention IPOs have different characteristics than the low attention ones. After controlling for various effects, we show that investor attention still remains a strong component of the high initial returns (the underpricing), primarily for the high sentiment periods. Moreover, we demonstrate that the investor attention partially explains the overoptimistic market reaction and thus also a part of the long-term underperformance

Cloning and characterisation of a bZIP transcription factor from a resurrection grass, Eragrostis nindensis

Includes bibliographical references (leaves 43-56).The G-box is a plant DNA cis-acting element involved in the regulation of gene expression in response to a range of environmental signals including anaerobiosis, dehydration and light as well as by abscisic acid (ABA). Basic leucine zipper (bZIP) transcription factors have been shown to specifically bind and activate transcription from G-boxes in a dimerized form. A 1.5 kb cDNA for a bZIP class transcription factor, designated EnGBF1, was cloned from a desiccation-tolerant grass, Eragrostis nindensis by degenerate RT-PCR

Hydroelastic waves and their interaction with fixed structures

A selection of problems are presented which study the interaction of hydroelastic waves with fixed structures. A thin floating elastic plate model is considered which primarily represents a continuous floating ice sheet, but may also be applied to very large floating platforms. The incident hydroelastic waves are assumed to either propagate from long–distance towards the structures or be generated by a moving load. All aspects of the subsequent interaction are studied in detail. The elastic plate is clamped to the fixed vertical structures to model an ice sheet frozen to the structure boundary. Both linear and nonlinear formulations are admitted for a selection of two– and three–dimensional problems. For the linear problems, selection of appropriate integral transforms leads to explicit analytical solutions in terms of integral quadratures. For the nonlinear case, the numerical solution is found by application of Green’s second identity combined with a boundary element method. The resulting deflection fields are analysed as well as the strain in the ice sheet due to curvature from the hydroelastic waves. Particular attention is paid to the strain at the ice–structure boundary. The integral transforms also lead to concise expressions for the horizontal and vertical wave forces impacting on the structure. It is shown that these forces may reach a substantial magnitude and must be taken into account for the design of structures in ice–covered water. Several assumptions are utilised which allow the problems to be mathematically treatable while retaining accuracy. Realistic effects such as viscoelasticity and fluid stratification are studied. The solutions are investigated in detail under the variation of physical parameters of the fluid, the ice sheet and the incident/load–generated waves, based on realistic values from cold climate regions

Adopting national vegetation guidelines and the National Vegetation Information System (NVIS) framework in the Northern Territory

Guidelines and core attributes for site-based vegetation surveying and mapping developed for the Northern Territory, are relevant to botanical research, forestry typing, rangeland monitoring and reporting on the extent and condition of native and non-native vegetated landscapes. These initiatives are consistent with national vegetation guidelines and the National Vegetation Information System (NVIS) framework. This paper provides a synopsis of vegetation site data collection, classification and mapping in the Northern Territory, and discusses the benefits of consistency between the guidelines, core attributes and the NVIS framework; both of which has an emphasis on the NVIS hierarchical classification system for describing structural and floristic attributes of vegetation. The long-term aim of the NVIS framework is that national attributes are adopted at regional levels to enable comparability of vegetation information within survey and jurisdictional boundaries in the Northern Territory and across Australia. The guidelines and core attributes are incorporated in current and future vegetation survey and mapping programs in the Northern Territory