Intensive care in labour: a preliminary appraisal

This is a preliminary investigation into the value, function and practicability of an intensive care labour unit for highrisk cases. All the equipment necessary can be mounted on two standard theatre trolleys which can be moved to the patient's bedside, but there is no place at present for this equipment outside a teaching unit. The investigation reports on continuous foetal heart monitoring of 36 patients and simultaneous foetal scalp pH estimations on 16 of them. A high proportion of babies with low Apgar scores showed one of two (or both) characteristic foetal heart patterns during labour: (a) the well-known type 2 dip, (b) a steppe pattern not previously described as such. The latter is of importance because it is impossible to detect using only clinical methods.There was poor correlation between foetal pH values and Apgar rating, and between foetal pH values and monitor patterns. Moreover, the pH values of foetal scalp blood and foetal umbilical arterial and venous blood samples bore varying relations to one another. However, for practical purposes, a foetal scalp blood of pH less than 7·20 when associated with a maternofoetal pH difference of 0·250 or more should be regarded with anxiety. The place and value of intensive care are discussed

Intensive care in labour: A preliminary appraisal

This is a preliminary investigation into the value, function and practicability of an intensive care labour unit for highrisk cases. All the equipment necessary can be mounted on two standard theatre trolleys which can be moved to the patient's bedside, but there is no place at present for this equipment outside a teaching unit. The investigation reports on continuous foetal heart monitoring of 36 patients and simultaneous foetal scalp pH estimations on 16 of them. A high proportion of babies with low Apgar scores showed one of two (or both) characteristic foetal heart patterns during labour: (a) the well-known type 2 dip, (b) a steppe pattern not previously described as such. The latter is of importance because it is impossible to detect using only clinical methods. There was poor correlation between foetal pH values and Apgar rating, and between foetal pH values and monitor patterns. Moreover, the pH values of foetal scalp blood and foetal umbilical arterial and venous blood samples bore varying relations to one another. However, for practical purposes, a foetal scalp blood of pH less than 7·20 when associated with a maternofoetal pH difference of 0·250 or more should be regarded with anxiety. The place and value of intensive care are discussed

Particle abundance in a thermal plasma: quantum kinetics vs. Boltzmann equation

We study the abundance of a particle species in a thermalized plasma by introducing a quantum kinetic description based on the non-equilibrium effective action. A stochastic interpretation of quantum kinetics in terms of a Langevin equation emerges naturally. We consider a particle species that is stable in the vacuum and interacts with \emph{heavier} particles that constitute a thermal bath in equilibrium and define of a fully renormalized single particle distribution function. The distribution function thermalizes on a time scale determined by the \emph{quasiparticle} relaxation rate. The equilibrium distribution function depends on the full spectral density and features off-shell contributions to the particle abundance. A model of a bosonic field $\Phi$ in interaction with two \emph{heavier} bosonic fields is studied. We find substantial departures from the Bose-Einstein result both in the high temperature and the low temperature but high momentum region. In the latter the abundance is exponentially suppressed but larger than the Bose-Einstein result. We obtain the Boltzmann equation in renormalized perturbation theory and highlight the origin of the differences. We argue that the corrections to the abundance of cold dark matter candidates are observationally negligible and that recombination erases any possible spectral distortions of the CMB. However we expect that the enhancement at high temperature may be important for baryogenesis.Comment: 39 pages, 11 figures. Clarifying remarks. To appear in Physical Review

Observations Supporting the Role of Magnetoconvection in Energy Supply to the Quiescent Solar Atmosphere

Identifying the two physical mechanisms behind the production and sustenance of the quiescent solar corona and solar wind poses two of the outstanding problems in solar physics today. We present analysis of spectroscopic observations from the Solar and Heliospheric Observatory that are consistent with a single physical mechanism being responsible for a significant portion of the heat supplied to the lower solar corona and the initial acceleration of the solar wind; the ubiquitous action of magnetoconvection-driven reprocessing and exchange reconnection of the Sun's magnetic field on the supergranular scale. We deduce that while the net magnetic flux on the scale of a supergranule controls the injection rate of mass and energy into the transition region plasma it is the global magnetic topology of the plasma that dictates whether the released ejecta provides thermal input to the quiet solar corona or becomes a tributary that feeds the solar wind.Comment: 34 pages, 13 figures - In press Astrophysical Journal (Jan 1 2007

Recombination rate variation shapes barriers to introgression across butterfly genomes.

Hybridisation and introgression can dramatically alter the relationships among groups of species, leading to phylogenetic discordance across the genome and between populations. Introgression can also erode species differences over time, but selection against introgression at certain loci acts to maintain postmating species barriers. Theory predicts that species barriers made up of many loci throughout the genome should lead to a broad correlation between introgression and recombination rate, which determines the extent to which selection on deleterious foreign alleles will affect neutral alleles at physically linked loci. Here, we describe the variation in genealogical relationships across the genome among three species of Heliconius butterflies: H. melpomene (mel), H. cydno (cyd), and H. timareta (tim), using whole genomes of 92 individuals, and ask whether this variation can be explained by heterogeneous barriers to introgression. We find that species relationships vary predictably at the chromosomal scale. By quantifying recombination rate and admixture proportions, we then show that rates of introgression are predicted by variation in recombination rate. This implies that species barriers are highly polygenic, with selection acting against introgressed alleles across most of the genome. In addition, long chromosomes, which have lower recombination rates, produce stronger barriers on average than short chromosomes. Finally, we find a consistent difference between two species pairs on either side of the Andes, which suggests differences in the architecture of the species barriers. Our findings illustrate how the combined effects of hybridisation, recombination, and natural selection, acting at multitudes of loci over long periods, can dramatically sculpt the phylogenetic relationships among species

The Post-Eruptive Evolution of a Coronal Dimming

We discuss the post-eruptive evolution of a "coronal dimming" based on observations of the EUV corona from the Solar and Heliospheric Observatory and the Transition Region and Coronal Explorer. This discussion highlights the roles played by magnetoconvection-driven magnetic reconnection and the global magnetic environment of the plasma in the "filling" and apparent motion of the region following the eruption of a coronal mass ejection (CME). A crucial element in our understanding of the dimming region evolution is developed by monitoring the disappearance and reappearance of bright TRACE "moss" around the active region giving rise to the CME. We interpret the change in the TRACE moss as a proxy of the changing coronal magnetic field topology behind the CME front. We infer that the change in global magnetic topology also results in a shift of energy balance in the process responsible for the production of the moss emission while the coronal magnetic topology evolves from closed, to open and back to closed again because, following the eruption, the moss reforms around the active region in almost exactly its pre-event configuration. As a result of the moss evolution, combining our discussion with recent spectroscopic results of an equatorial coronal hole, we suggest that the interchangeable use of the term "transient coronal hole" to describe a coronal dimming is more than just a simple coincidence.Comment: In Press ApJ [May 2007] - 15 pages, 5 figures, 7 movies that are available upon request [contact author

Integrable Generalisations of the 2-dimensional Born Infeld Equation

The Born-Infeld equation in two dimensions is generalised to higher dimensions whilst retaining Lorentz Invariance and complete integrability. This generalisation retains homogeneity in second derivatives of the field.Comment: 11 pages, Latex, DTP/93/3

Optimal power generation scheduling of a shipboard power system

This paper studies the optimal power generation scheduling for a shipboard power system. The problem is formulated as a discrete-time Markov Decision Process (MDP). The paper considers the shipboard power system both without any energy storage and with energy storage, and obtains an optimal power generation scheduling for each situation. For the non-storage system, the switch cost during the start-up process is considered. For the system with a storage, a fuel consumption comparison with different energy storage sizes is provided.Center for Electromechanic

Spatial distribution of podoconiosis in relation to environmental factors in Ethiopia: a historical review

BACKGROUND An up-to-date and reliable map of podoconiosis is needed to design geographically targeted and cost-effective intervention in Ethiopia. Identifying the ecological correlates of the distribution of podoconiosis is the first step for distribution and risk maps. The objective of this study was to investigate the spatial distribution and ecological correlates of podoconiosis using historical and contemporary survey data. METHODS Data on the observed prevalence of podoconiosis were abstracted from published and unpublished literature into a standardized database, according to strict inclusion and exclusion criteria. In total, 10 studies conducted between 1969 and 2012 were included, and data were available for 401,674 individuals older than 15 years of age from 229 locations. A range of high resolution environmental factors were investigated to determine their association with podoconiosis prevalence, using logistic regression. RESULTS The prevalence of podoconiosis in Ethiopia was estimated at 3.4% (95% CI 3.3%-3.4%) with marked regional variation. We identified significant associations between mean annual Land Surface Temperature (LST), mean annual precipitation, topography of the land and fine soil texture and high prevalence of podoconiosis. The derived maps indicate both widespread occurrence of podoconiosis and a marked variability in prevalence of podoconiosis, with prevalence typically highest at altitudes >1500 m above sea level (masl), with >1500 mm annual rainfall and mean annual LST of 19-21°C. No (or very little) podoconiosis occurred at altitudes 24°C. CONCLUSION Podoconiosis remains a public health problem in Ethiopia over considerable areas of the country, but exhibits marked geographical variation associated in part with key environmental factors. This is work in progress and the results presented here will be refined in future work