Anemia and red blood cell transfusion in neurocritical care

YesFunding provided by the Open Access Authors Fund

One Size Fits All? Molecular Evidence for a Commonly Inherited Petal Identity Program in Ranunculales

Petaloid organs are a major component of the floral diversity observed across nearly all major clades of angiosperms. The variable morphology and development of these organs has led to the hypothesis that they are not homologous but, rather, have evolved multiple times. A particularly notable example of petal diversity, and potential homoplasy, is found within the order Ranunculales, exemplified by families such as Ranunculaceae, Berberidaceae, and Papaveraceae. To investigate the molecular basis of petal identity in Ranunculales, we used a combination of molecular phylogenetics and gene expression analysis to characterize APETALA3 (AP3) and PISTILLATA (PI) homologs from a total of 13 representative genera of the order. One of the most striking results of this study is that expression of orthologs of a single AP3 lineage is consistently petal-specific across both Ranunculaceae and Berberidaceae. We conclude from this finding that these supposedly homoplastic petals in fact share a developmental genetic program that appears to have been present in the common ancestor of the two families. We discuss the implications of this type of molecular data for long-held typological definitions of petals and, more broadly, the evolution of petaloid organs across the angiosperms.Organismic and Evolutionary Biolog

Intrinsic Geometry of a Null Hypersurface

We apply Cartan's method of equivalence to construct invariants of a given null hypersurface in a Lorentzian space-time. This enables us to fully classify the internal geometry of such surfaces and hence solve the local equivalence problem for null hypersurface structures in 4-dimensional Lorentzian space-times

Consumption of Solid Food by Suckling Pigs: Individual Variation and Relation to Weight Gain

Individual daily consumption of supplementary solid food (\u27creep feed\u27) was measured from Day 10 to weaning at Day 28 for 39 piglets in four litters, and its relationship to body weight and weight gain up to Day 42 was investigated. Individual consumption was measured by combining the weight of the feed removed from the dispensers (monitored electronically) and a video image of piglet activity at the feeder. Creep feed consumption varied greatly, both between and within litters. On average, pigs began feeding on Day 12 (range Day 10-28), intake was relatively low (usually \u3c 5 g day ‒1) until Day 20 but increased considerably in the week before weaning, with a mean intake of 63 g day ‒1 (range 2-205 g day ‒1) during that week. Over the entire creep-feeding period, total feed consumption ranged from 13-1911 g per pig. Within litters, intake was positively correlated with birth weight (P \u3c 0.05) and the correlation with weight gains to Day 20 tended to be positive rather than negative. This suggests that greater creep feed intake was typical of the larger and more mature piglets, rather than serving as compensation for poor milk intake among the more deprived litter-mates. However, one exceptional pig began, on Day 14 after several days of weight loss, to eat more creep feed than any other piglet studied, suggesting that compensatory creep feeding can occur at a young age in exceptional cases. In a multiple regression analysis, creep feed intake accounted for 37% of the variation in weight gain in the week before weaning (P \u3c 0.001) and 7% of the variation in gain from Day 10 to weaning (P \u3c 0.01) after variation attributable to antecedent variables had been taken into account. Within-litter differences in weight gain during the 2 weeks after weaning were correlated with weight at birth and weight gain before weaning (P \u3c 0.05), but not with pre-weaning creep feed intake. Hence, creep feed intake appeared to contribute to pre-weaning gains and these in turn were correlated with post-weaning gains; however, a more direct effect of pre-weaning creep feed intake on post-weaning gain could not be detected

Wind Signatures In The X-Ray Emission-Line Profiles Of The Late-O Supergiant Zeta Orionis

X-ray line-profile analysis has proved to be the most direct diagnostic of the kinematics and spatial distribution of the very hot plasma around O stars. The Doppler-broadened line profiles provide information about the velocity distribution of the hot plasma, while the wavelength-dependent attenuation across a line profile provides information about the absorption to the hot plasma, thus providing a strong constraint on its physical location. In this paper, we apply several analysis techniques to the emission lines in the Chandra High Energy Transmission Grating Spectrometer (HETGS) spectrum of the late-O supergiant zeta Ori (O9.7 Ib), including the fitting of a simple line-profile model. We show that there is distinct evidence for blueshifts and profile asymmetry, as well as broadening in the X-ray emission lines of zeta Ori. These are the observational hallmarks of a wind-shock X-ray source, and the results for zeta Ori are very similar to those for the earlier O star, zeta Pup, which we have previously shown to be well fit by the same wind-shock line-profile model. The more subtle effects on the line-profile morphologies in zeta Ori, as compared to zeta Pup, are consistent with the somewhat lower density wind in this later O supergiant. In both stars, the wind optical depths required to explain the mildly asymmetric X-ray line profiles imply reductions in the effective opacity of nearly an order of magnitude, which may be explained by some combination of mass-loss rate reduction and large-scale clumping, with its associated porosity-based effects on radiation transfer. In the context of the recent reanalysis of the helium-like line intensity ratios in both zeta Ori and zeta Pup, and also in light of recent work questioning the published mass-loss rates in OB stars, these new results indicate that the X-ray emission from zeta Ori can be understood within the framework of the standard wind-shock scenario for hot stars

Can the design of glove dispensing boxes influence glove contamination?

Background Few studies have explored the microbial contamination of glove boxes in clinical settings. The objective of this observational study was to investigate whether a new glove packaging system in which gloves are dispensed one by one vertically with the cuff-end first has lower levels of contamination on the gloves and on the surface around the box aperture compared to conventional horizontally dispensed glove boxes. Methods Seven participating sites were provided with vertical glove dispensing systems and conventional boxes. Before opening boxes, the surface around the aperture was sampled microbiologically to establish base-line levels of superficial contamination. Once the boxes were opened, the first pair of gloves in each box were sampled for viable bacteria. Thereafter, testing sites were visited on a weekly basis over a period of six weeks and the same microbiological assessments made. Results The surface surrounding the aperture of the modified dispenser boxes became significantly less contaminated than the conventional boxes (P < 0.001) with an average of 46.7% less contamination around the aperture. Overall, gloves from modified boxes showed significantly less colony-forming units contamination than gloves from conventional boxes (P < 0.001). Comparing all sites over the entire six-week period, modified dispensed gloves had 88.9% less bacterial contamination. Conclusion This simple improvement to glove box design reduces contamination of unused gloves. Such modifications could decrease the risk of microbial cross-transmission in settings that utilise gloves. However, such advantages do not substitute for strict hand-hygiene compliance and appropriate use of non-sterile, single-use gloves

Solution generating with perfect fluids

We apply a technique, due to Stephani, for generating solutions of the Einstein-perfect fluid equations. This technique is similar to the vacuum solution generating techniques of Ehlers, Harrison, Geroch and others. We start with a ``seed'' solution of the Einstein-perfect fluid equations with a Killing vector. The seed solution must either have (i) a spacelike Killing vector and equation of state P=rho or (ii) a timelike Killing vector and equation of state rho+3P=0. The new solution generated by this technique then has the same Killing vector and the same equation of state. We choose several simple seed solutions with these equations of state and where the Killing vector has no twist. The new solutions are twisting versions of the seed solutions

Conflict and Cooperation: Sociobiological Principles and the Behaviour of Pigs

The pig provides many examples of how principles of behavioural ecology and sociobiology can lead to insights into farm animal behaviour. According to parent-offspring conflict theory, parents should tend to give a level of parental investment somewhat below that solicited by the young. When closely confined during lactation, sows can do little to limit the amount of contact with the piglets, and the young stimulate a prolonged, high level of lactation. Certain alternative housing systems allow the sow to limit the stimulation she receives, and the resulting reduction in lactation can actually be advantageous to both parties. Communal care of offspring has both advantages and disadvantages in various species; these may help to explain why communal care occurs to a limited extent in pigs, and why sows isolate their litters in early lactation. Neonatal competition and mortality among newborn piglets have strong parallels in the “facultative siblicide” which adjusts brood size in numerous species of birds. These species typically produce slightly more young than are normally raised, and the number of siblings that survive is determined by the ability of the smaller young to withstand intense competition. The hypothesis that pigs have evolved a similar system of brood reduction may explain why piglet mortality is such an enduring problem and requires solutions different from those that work for other domestic species. Resource defence theory provides a functional framework for studies of aggressive behaviour. Factors determining the defensibility of a resource include its degree of clumping in time and space, and these suggest ways to reduce competition for food and other resources. However, aggression involved in establishing social dominance is more likely to be influenced by manipulating traits of the competing animals (competitive ability, familiarity) rather than the defensibility of resources. We conclude that principles of behavioural ecology and sociobiology provide a useful functional and evolutionary perspective to complement other approaches to the study of farm animal behaviour

Conflict and Cooperation: Sociobiological Principles and the Behaviour of Pigs

The pig provides many examples of how principles of behavioural ecology and sociobiology can lead to insights into farm animal behaviour. According to parent-offspring conflict theory, parents should tend to give a level of parental investment somewhat below that solicited by the young. When closely confined during lactation, sows can do little to limit the amount of contact with the piglets, and the young stimulate a prolonged, high level of lactation. Certain alternative housing systems allow the sow to limit the stimulation she receives, and the resulting reduction in lactation can actually be advantageous to both parties. Communal care of offspring has both advantages and disadvantages in various species; these may help to explain why communal care occurs to a limited extent in pigs, and why sows isolate their litters in early lactation. Neonatal competition and mortality among newborn piglets have strong parallels in the “facultative siblicide” which adjusts brood size in numerous species of birds. These species typically produce slightly more young than are normally raised, and the number of siblings that survive is determined by the ability of the smaller young to withstand intense competition. The hypothesis that pigs have evolved a similar system of brood reduction may explain why piglet mortality is such an enduring problem and requires solutions different from those that work for other domestic species. Resource defence theory provides a functional framework for studies of aggressive behaviour. Factors determining the defensibility of a resource include its degree of clumping in time and space, and these suggest ways to reduce competition for food and other resources. However, aggression involved in establishing social dominance is more likely to be influenced by manipulating traits of the competing animals (competitive ability, familiarity) rather than the defensibility of resources. We conclude that principles of behavioural ecology and sociobiology provide a useful functional and evolutionary perspective to complement other approaches to the study of farm animal behaviour

Profile instabilities of the millisecond pulsar PSR J1022+1001

We present evidence that the integrated profiles of some millisecond pulsars exhibit severe changes that are inconsistent with the moding phenomenon as known from slowly rotating pulsars. We study these profile instabilities in particular for PSR J1022+1001 and show that they occur smoothly, exhibiting longer time constants than those associated with moding. In addition, the profile changes of this pulsar seem to be associated with a relatively narrow-band variation of the pulse shape. Only parts of the integrated profile participate in this process which suggests that the origin of this phenomenon is intrinsic to the pulsar magnetosphere and unrelated to the interstellar medium. A polarization study rules out profile changes due to geometrical effects produced by any sort of precession. However, changes are observed in the circularly polarized radiation component. In total we identify four recycled pulsars which also exhibit instabilities in the total power or polarization profiles due to an unknown phenomenon (PSRs J1022+1001, J1730-2304, B1821-24, J2145-0750). The consequences for high precision pulsar timing are discussed in view of the standard assumption that the integrated profiles of millisecond pulsars are stable. As a result we present a new method to determine pulse times-of-arrival that involves an adjustment of relative component amplitudes of the template profile. Applying this method to PSR J1022+1001, we obtain an improved timing solution with a proper motion measurement of -17 \pm 2 mas/yr in ecliptic longitude. Assuming a distance to the pulsar as inferred from the dispersion measure this corresponds to an one-dimensional space velocity of 50 km/s.Comment: 29 pages, 12 figures, accepted for publication in Ap