The impact of CoRoT on close binary research

The space experiment CoRoT will provide continuous monitoring and high accuracy light curves of about sixty thousand stars. Selected binary systems will be observed in the Additional Program frame as targets of long and continuous pointed observations. Moreover, thousands of new binaries will certainly be detected and hundreds of them will have extremely accurate light curves. This will allow studies of fine effects on the light curves, monitoring of stellar activity and, in combination with ground-based observations, will provide exquisite determination of stellar parameters. Among the new discoveries of interesting systems of special value will be those of low mass binaries.Comment: 6 pages, 2 figures, contribution to "Colse binaries in the 21th century", Syros (Greece), June 2005. To be published by Ap&S

The oldest peracarid crustacean reveals a Late Devonian freshwater colonization by isopod relatives.

Peracarida (e.g. woodlice and side-swimmers) are, together with their sister-group Eucarida (e.g. krill and decapods), the most speciose group of modern crustaceans, suggested to have appeared as early as the Ordovician. While eucarids' incursion onto land consists of mainly freshwater and littoral grounds, some peracarids have evolved fully terrestrial ground-crawling ecologies, inhabiting even our gardens in temperate regions (e.g. pillbugs and sowbugs). Their fossil record extends back to the Carboniferous and consists mainly of marine occurrences. Here, we provide a complete re-analysis of a fossil arthropod-Oxyuropoda-reported in 1908 from the Late Devonian floodplains of Ireland, and left with unresolved systematic affinities despite a century of attempts at identification. Known from a single specimen preserved in two dimensions, we analysed its anatomy using digital microscopy and multispectral macroimaging to enhance the contrast of morphological structures. The new anatomical characters and completeness of Oxyuropoda, together with a phylogenetic analysis with representatives of all major Eumalacostraca groups, indicate that Oxyuropoda is a crown peracarid, part of a clade including amphipods and isopods. As such, Oxyuropoda is the oldest known species Peracarida, and provides evidence that derived peracarids had an incursion into freshwater and terrestrial environments as early as the Famennian, more than 360 Ma

On the Existence and Uniqueness of Equilibrium in the Bottleneck Model with Atomic Users

This paper investigates the existence and uniqueness of equilibrium in the Vickrey bottleneck model when each user controls a positive fraction of total traffic. Users simultaneously choose departure schedules for their vehicle fleets. Each user internalizes the congestion cost that each of its vehicles imposes on other vehicles in its fleet. We establish three results. First, a pure strategy Nash equilibrium (PSNE) may not exist. Second, if a PSNE does exist, identical users may incur appreciably different equilibrium costs. Finally, a multiplicity of PSNE can exist in which no queuing occurs but departures begin earlier or later than in the system optimum. The order in which users depart can be suboptimal as well. Nevertheless, by internalizing self-imposed congestion costs individual users can realize much, and possibly all, of the potential cost savings from either centralized traffic control or time-varying congestion tolls

The wheezy infant and toddler asthmatic - a primary care approach

Wheeze is common in infants and young children. Asthma is but one cause and it is obviously important to exclude or include as it is amenable to specific therapy. It is also obvious that the pre-school or young child is not just a smaller variety of the older child or adult and this is especially true of asthma, where special situations exist with regard to diagnosis and treatment. Although there is a differential diagnosis for the major symptoms that constitute asthma in this age group, no child should be left to wheeze or cough without the possibility of asthma being considered and excluded. New guidelines and reports suggest that differentiation of virally induced wheeze from multi-trigger wheeze (or toddler asthma) is less important than making an attempt to manage the child. If an infant, or young child, has a chronic wheeze and is atopic or responds to a bronchodilator, asthma is more likely and therapy should be tried. If, however, there is no response to the therapy, investigate for other causes. Remember that in South Africa wheeze may also be produced by chronic infections, gastro-oesophageal reflux, cardiac failure, cystic fibrosis and a host of other sinister conditions. Therapeutically, for mild and intermittent wheeze the choice of inhaled corticosteroid (ICS) or a leukotriene antagonist may be valuable options. Therapy is intermittent and should be started pre-emptively. However, for more severe and frequent symptoms regular use of ICS (moderate dose) is clearly the best therapeutic option.http://reference.sabinet.co.za/sa_epublication/caciam2016Paediatrics and Child Healt

A self-consistent dynamical model of the Milky Way disc adjusted to Gaia data

Context. Accurate astrometry achieved by Gaia for many stars in the Milky Way provides an opportunity to reanalyse the Galactic stellar populations from a large and homogeneous sample and to revisit the Galaxy gravitational potential. Aims. This paper shows how a self-consistent dynamical model can be obtained by fitting the gravitational potential of the Milky Way to the stellar kinematics and densities from Gaia data. Methods. We derived a gravitational potential using the Besancon Galaxy Model, and computed the disc stellar distribution functions based on three integrals of motion (E, Lz, I3) to model stationary stellar discs. The gravitational potential and the stellar distribution functions are built self-consistently, and are then adjusted to be in agreement with the kinematics and the density distributions obtained from Gaia observations. A Markov chain Monte Carlo (MCMC) is used to fit the free parameters of the dynamical model to Gaia parallax and proper motion distributions. The fit is done on several sets of Gaia data, mainly a subsample of the GCNS (Gaia catalogue of nearby stars to 100 pc) with G< 17, together with 26 deep fields selected from eDR3, widely spread in longitudes and latitudes. Results. We are able to determine the velocity dispersion ellipsoid and its tilt for subcomponents of different ages, both varying with R and z. The density laws and their radial scale lengths for the thin and thick disc populations are also obtained self-consistently. This new model has some interesting characteristics that come naturally from the process, such as a flaring thin disc. The thick disc is found to present very distinctive characteristics from the old thin disc, both in density and kinematics. This lends significant support to the idea that thin and thick discs were formed in distinct scenarios, as the density and kinematics transition between them is found to be abrupt. The dark matter halo is shown to be nearly spherical. We also derive the solar motion with regards to the Local Standard of Rest (LSR), finding U· = 10.79 ± 0.56 km s-1, V· = 11.06 ± 0.94 km s-1, and W· = 7.66 ± 0.43 km s-1, in close agreement with recent studies. Conclusions. The resulting fully self-consistent gravitational potential, still axisymmetric, is a good approximation of a smooth mass distribution in the Milky Way and can be used for further studies, including finding streams, substructures, and to compute orbits for real stars in our Galaxy

Common variable immunodeficiency disorders : what generalists should know

Primary immune deficiency disorders (PIDDs) are common and underdiagnosed. Predominant antibody deficiencies (PADs) are the most common type of immune deficiency and comprise 55% of the immune deficiencies diagnosed. Although immunoglobulin A (IgA) deficiency remains the most common type of PID, common variable immunodeficiency disorders remain the most common symptomatic PID for which medical therapy is sought.https://journals.co.za/journal/m.ajtccmam2022Paediatrics and Child Healt

The Dark Matter Density in the Solar Neighborhood reconsidered

Both the gas flaring and the dip in the rotation curve, which was recently reconfirmed with precise measurements using the VERA VLBI array in Japan, suggest doughnut-like substructure in the dark matter (DM) halo. A global fit to all available data shows that the data are indeed best described by an NFW DM profile complemented by two doughnut-like DM substructures with radii of 4.2 and 12.4 kpc, which coincide with the local dust ring and the Monocerus ring of stars, respectively. Both regions have been suggested as regions with tidal streams from "shredded" satellites. If real, the radial extensions of these nearby ringlike structures enhance the local dark matter density by a factor of four to about 1.3$\pm0.3$ GeV/cm$^3$. It is shown that i) this higher DM density is perfectly consistent with the local gravitational potential determining the surface density and the local matter density (Oort limit), ii) previous determinations of the surface density were biased by the assumption of a smoothly varying DM halo and iii) the s-shaped gas flaring is explained. Such a possible enhancement of the local DM density is of great interest for direct DM searches and would change the directional dependence for indirect DM searches.Comment: 14 pages, 4 figures, extended version, accepted for publication in JCA

Prevalence of Blomia tropicalis allergy in two regions of South Africa

BACKGROUND. Asthma and allergic rhinitis affect 15% and 38% of South African (SA) children, respectively. The housedust mite (HDM) is the most significant indoor aeroallergen. Typical HDM species include Dermatophagoides pteronyssinus, D. farinae and Blomia tropicalis. Conventional skin-prick testing (SPT) panels only test for Dermatophagoides. B. tropicalis has been described in the tropical and subtropical regions, but is not routinely tested for in SA. OBJECTIVE. To ascertain the significance of B. tropicalis as an aeroallergen in northern coastal KwaZulu-Natal Province (KZN), a tropical environment, and in Johannesburg in the highveld, where the climate is milder and less humid. METHODS. Children aged 1 - 18 years with features of allergic rhinitis and/or asthma were recruited over a 6-month period from Alberlito Hospital in northern KZN and the Clinton Clinic in Johannesburg. SPTs included Dermatophagoides and B. tropicalis. Sensitisation was defined as a wheal 3 mm greater than the negative control. RESULTS. Eighty-five subjects were included, 50 in northern KZN and 35 in the Johannesburg arm; 52% of subjects in northern KZN and 3% in Johannesburg were sensitised to B. tropicalis, with a significant difference between these centres (p<0.05). Of the 52% sensitised to B. tropicalis in northern KZN, half were sensitised only to B. tropicalis. CONCLUSION. There is a high prevalence of B. tropicalis allergy in the tropical northern KZN region and a much lower prevalence in the Johannesburg region. Routine testing for B. tropicalis allergy should be employed in northern KZN.http://www.samj.org.zaam201

CCD BV and 2MASS photometric study of the open cluster NGC 1513

We present CCD BV and JHK$_{s}$ 2MASS photometric data for the open cluster NGC 1513. We observed 609 stars in the direction of the cluster up to a limiting magnitude of $V\sim19$ mag. The star count method shows that the centre of the cluster lies at $\alpha_{2000}=04^{h}09^{m}36^{s}$, $\delta_{2000}=49^{\circ}28^{'}43^{''}$ and its angular size is $r=10$ arcmin. The optical and near-infrared two-colour diagrams reveal the colour excesses in the direction of the cluster as $E(B-V)=0.68\pm0.06$, $E(J-H)=0.21\pm0.02$ and $E(J-K_{s})=0.33\pm0.04$ mag. These results are consistent with normal interstellar extinction values. Optical and near-infrared Zero Age Main-Sequences (ZAMS) provided an average distance modulus of $(m-M)_{0}=10.80\pm0.13$ mag, which can be translated into a distance of $1440\pm80$ pc. Finally, using Padova isochrones we determined the metallicity and age of the cluster as $Z=0.015\pm 0.004$ ($[M/H]=-0.10 \pm 0.10$ dex) and $\log (t/yr) = 8.40\pm0.04$, respectively.Comment: 15 pages, 12 figures and 4 tables, accepted for publication in Astrophysics & Space Scienc