Rotating solenoidal perfect fluids of Petrov type D

We prove that aligned Petrov type D perfect fluids for which the vorticity vector is not orthogonal to the plane of repeated principal null directions and for which the magnetic part of the Weyl tensor with respect to the fluid velocity has vanishing divergence, are necessarily purely electric or locally rotationally symmetric. The LRS metrics are presented explicitly.Comment: 6 pages, no figure

Purely radiative perfect fluids

We study `purely radiative' (div E = div H = 0) and geodesic perfect fluids with non-constant pressure and show that the Bianchi class A perfect fluids can be uniquely characterized --modulo the class of purely electric and (pseudo-)spherically symmetric universes-- as those models for which the magnetic and electric part of the Weyl tensor and the shear are simultaneously diagonalizable. For the case of constant pressure the same conclusion holds provided one also assumes that the fluid is irrotational.Comment: 12 pages, minor grammatical change

Globular Cluster Systems of Early-Type Galaxies

Properties of 53 globular cluster systems are investigated. Strong correlations are found between parent galaxy luminosity and both the slope of the radial density profile for clusters and the width of the cluster color (metallicity) distribution. These correlations are in the sense that the most luminous early-type galaxies are embedded in cluster systems that have the shallowest radial gradients and exhibit the broadest color distributions. The data suggest a scenario in which luminous early-type galaxies have a more complex evolutionary history than fainter ones. A problem with the interpretation of the present data is that it is difficult (or impossible) to disentangle the strongly correlated effects of high parent galaxy luminosity, presence of a core or boxy isophotes, and shallow radial cluster density gradients.Comment: Contains complete Table 1 which had been truncated. To appear in the Astrophysical Journal. Also available at http://www.hia.nrc.ca/eprints.htm

Shearfree perfect fluids with solenoidal magnetic curvature and a gamma-law equation of state

We show that shearfree perfect fluids obeying an equation of state p=(gamma -1) mu are non-rotating or non-expanding under the assumption that the spatial divergence of the magnetic part of the Weyl tensor is zero.Comment: 11 page

Shear-free perfect fluids with a solenoidal electric curvature

We prove that the vorticity or the expansion vanishes for any shear-free perfect fluid solution of the Einstein field equations where the pressure satisfies a barotropic equation of state and the spatial divergence of the electric part of the Weyl tensor is zero.Comment: 9 page

Changing priorities in maternal and perinatal health in Gert Sibande District, South Africa

Gert Sibande District is a predominantly rural district in Mpumalanga Province, South Africa (SA), with a population of just over 1.1 million. It has a high prevalence of HIV infection and pregnancy-related hypertensive disease. In 2010 the district was one of the worst-performing health districts in SA, with a maternal mortality ratio of 328.0 per 100 000 births. Various programmes were introduced between 2010 and 2017 to address major causes of maternal and perinatal morbidity and mortality in the district. The focus has been on HIV-related morbidity, the direct obstetric causes of maternal and perinatal morbidity and mortality, and health systems strengthening. During the period 2010 - 2017, there was a steady decline in institutional maternal mortality with a drop of 71% in maternal deaths over a period of 6 years, from 328.0 per 100 000 births to 95.0. However, the ratio levelled off in 2016 and 2017, mainly as a result of a changing disease profile. The stillbirth rate showed a decline of 24.4% over a period of 8 years. With perseverance, rapid response and evidence-based strategies it was possible to more than halve the institutional maternal mortality ratio within 6 years. However, with the changing disease profile, conditions such as hypertensive disease in pregnancy should be prioritised and new strategies developed to further reduce maternal and perinatal mortality and morbidity

Tools for understanding the agricultural production systems and their socio-economic context in target regions for the introduction of new banana cultivars: baseline intra-household survey.

Within the framework of the IITA-led project “Improvement of banana for smallholder farmers in the Great Lakes region of Africa” (also known as the “Breeding Better Bananas” project, http://breedingbetterbananas.org), Bioversity International and partners conducted baseline research in the target regions of Luwero and Mbarara in Uganda, and Bukoba, Meru, Moshi and Rungwe in Tanzania during 2015-2016, prior to conducting on-station and on-farm evaluations of the new NARITA banana cultivars. Five tools were used to characterise the banana and agricultural production systems, and the socioeconomic context of these systems, in the target regions. The research used a mixed-methods, participatory and sex-disaggregated approach to ensure that the knowledge, experiences and opinions of as many people as possible were obtained. The understanding gained from the baseline research will: • Be fed into the banana breeding pipeline at multiple entry points to assist with breeding banana cultivars that better meet the requirements of the users. Some of these entry points are: setting of breeding targets; selection of parent material; evaluation in regional on-station and on-farm trials; participatory varietal selection taking into account the criteria (or ‘trait preferences’) that are important to multiple and different users; facilitating access to and adoption of the new cultivars by farmers and other end-users through scaling up the supply of clean planting materials and ensuring equitable distribution of these through the ‘seed’ systems. • Inform the ongoing adaptive management of the project activities to ensure fair participation and decision-making by people in the affected communities. • Provide the baseline to evaluate, in conjunction with the endline, the impact of adoption of the new cultivars on households, and individuals within, in the target regions

Purely gravito-magnetic vacuum space-times

It is shown that there are no vacuum space-times (with or without cosmological constant) for which the Weyl-tensor is purely gravito-magnetic with respect to a normal and timelike congruence of observers.Comment: 4 page

Silent universes with a cosmological constant

We study non-degenerate (Petrov type I) silent universes in the presence of a non-vanishing cosmological constant L. In contrast to the L=0 case, for which the orthogonally spatially homogeneous Bianchi type I metrics most likely are the only admissible metrics, solutions are shown to exist when L is positive. The general solution is presented for the case where one of the eigenvalues of the expansion tensor is 0.Comment: 11 pages; several typos corrected which were still present in CGQ version; minor change

Near-Infrared Adaptive Optics Imaging of the Central Regions of Nearby Sc Galaxies: I. M33

Near-infrared images obtained with the Canada-France-Hawaii Telescope (CFHT) Adaptive Optics Bonnette (AOB) are used to investigate the stellar content within 18 arcsec of the center of the Local Group spiral galaxy M33. AGB stars with near-infrared spectral-energy distributions similar to those of giants in the solar neighborhood and Baade's Window are detected over most of the field. The bolometric luminosity function (LF) of these stars has a discontinuity near M_{bol} = -5.25, and comparisons with evolutionary tracks suggest that most of the AGB stars formed in a burst of star formation 1 - 3 Gyr in the past. The images are also used to investigate the integrated near-infrared photometric properties of the nucleus and the central light concentration. The nucleus is bluer than the central light concentration, in agreement with previous studies at visible wavelengths. The CO index of the central light concentration 0.5 arcsec from the galaxy center is 0.05, which corresponds to [Fe/H] = -1.2 for simple stellar systems. Hence, the central light concentration could not have formed from the chemically-enriched material that dominates the present-day inner disk of M33.Comment: 23 pages of text + 11 figures; to appear in A