Infusion of donor leukocytes to induce tolerance in organ allograft recipients

To further enhance chimerism, 229 primary allograft recipients have received perioperative intravenous infusion of a single dose of 3 to 6 x 108 unmodified donor bone marrow (BM) cells/kg body weight. In addition, 42 patients have been accrued in a concurrent protocol involving multiple (up to three) sequential perioperative infusions of 2 x 108 BM cells/kg/day from day 0-2 posttransplantation (PTx). Organ recipients (n = 133) for whom BM was not available were monitored as controls. The infusion of BM was safe and except for 50 (18%), all study patients have optimal graft function. Of the control patients, allografts in 30 (23%) have been lost during the course of follow-up. The cumulative risk of acute cellular rejection (ACR) was statistically lower in the study patients compared with that of controls. It is interesting that, 62% of BM-augmented heart recipients were free of ACR (Grade ≥ 3A) in the first 6 months PTx compared to controls. The incidence of obliterative bronchiolitis was also statistically lower in study lung recipients (3.8%) compared with the contemporaneously acquired controls (31%). The levels of donor cell chimerism were at least a log higher in the peripheral blood of majority of the study patients compared with that of controls. The incidence of donor-specific hyporeactivity, as determined by one-way mixed leukocyte reaction, was also higher in those BM-augmented liver, kidney, and lung recipients that could be evaluated compared to controls

Radio Observations of the Supernova Remnant Candidate G312.5-3.0

The radio images from the Parkes-MIT-NRAO (PMN) Southern Sky Survey at 4850 MHz have revealed a number of previously unknown radio sources. One such source, G312.5-3.0 (PMN J1421-6415), has been observed using the multi-frequency capabilities of the Australia Telescope Compact Array (ATCA) at frequencies of 1380 MHz and 2378 MHz. Further observations of the source were made using the Molonglo Observatory Synthesis Telescope (MOST) at a frequency of 843 MHz. The source has an angular size of 18 arcmin and has a distinct shell structure. We present the reduced multi-frequency observations of this source and provide a brief argument for its possible identification as a supernova remnant.Comment: 5 pages, 5 figures, Accepted for publication in MNRA

WISE Brown Dwarf Binaries: The Discovery of a T5+T5 and a T8.5+T9 System

The multiplicity properties of brown dwarfs are critical empirical constraints for formation theories, while multiples themselves provide unique opportunities to test evolutionary and atmospheric models and examine empirical trends. Studies using high-resolution imaging cannot only uncover faint companions, but they can also be used to determine dynamical masses through long-term monitoring of binary systems. We have begun a search for the coolest brown dwarfs using preliminary processing of data from the Wide-field Infrared Survey Explorer and have confirmed many of the candidates as late-type T dwarfs. In order to search for companions to these objects, we are conducting observations using the Laser Guide Star Adaptive Optics system on Keck II. Here we present the first results of that search, including a T5 binary with nearly equal mass components and a faint companion to a T8.5 dwarf with an estimated spectral type of T9

WISE J163940.83-684738.6: A Y Dwarf identified by Methane Imaging

We have used methane imaging techniques to identify the near-infrared counterpart of the bright WISE source WISEJ163940.83-684738.6. The large proper motion of this source (around 3.0arcsec/yr) has moved it, since its original WISE identification, very close to a much brighter background star -- it currently lies within 1.5" of the J=14.90+-0.04 star 2MASS16394085-6847446. Observations in good seeing conditions using methane sensitive filters in the near-infrared J-band with the FourStar instrument on the Magellan 6.5m Baade telescope, however, have enabled us to detect a near-infrared counterpart. We have defined a photometric system for use with the FourStar J2 and J3 filters, and this photometry indicates strong methane absorption, which unequivocally identifies it as the source of the WISE flux. Using these imaging observations we were then able to steer this object down the slit of the FIRE spectrograph on a night of 0.6" seeing, and so obtain near-infrared spectroscopy confirming a Y0-Y0.5 spectral type. This is in line with the object's near-infrared-to-WISE J3--W2 colour. Preliminary astrometry using both WISE and FourStar data indicates a distance of 5.0+-0.5pc and a substantial tangential velocity of 73+-8km/s. WISEJ163940.83-684738.6 is the brightest confirmed Y dwarf in the WISE W2 passband and its distance measurement places it amongst the lowest luminosity sources detected to date.Comment: Accepted for publication in The Astrophysical Journal, 20 September 201

The importance of transport model uncertainties for the estimation of CO2 sources and sinks using satellite measurements

This study presents a synthetic model intercomparison to investigate the importance of transport model errors for estimating the sources and sinks of CO2 using satellite measurements. The experiments were designed for testing the potential performance of the proposed CO2 lidar A-SCOPE, but also apply to other space borne missions that monitor total column CO2. The participating transport models IFS, LMDZ, TM3, and TM5 were run in forward and inverse mode using common a priori CO2 fluxes and initial concentrations. Forward simulations of column averaged CO2 (xCO2) mixing ratios vary between the models by s=0.5 ppm over the continents and s=0.27 ppm over the oceans. Despite the fact that the models agree on average on the sub-ppm level, these modest differences nevertheless lead to significant discrepancies in the inverted fluxes of 0.1 PgC/yr per 106 km2 over land and 0.03 PgC/yr per 106 km2 over the ocean. These transport model induced flux uncertainties exceed the target requirement that was formulated for the A-SCOPE mission of 0.02 PgC/yr per 106 km2, and could also limit the overall performance of other CO2 missions such as GOSAT. A variable, but overall encouraging agreement is found in comparison with FTS measurements at Park Falls, Darwin, Spitsbergen, and Bremen, although systematic differences are found exceeding the 0.5 ppm level. Because of this, our estimate of the impact of transport model uncerainty is likely to be conservative. It is concluded that to make use of the remote sensing technique for quantifying the sources and sinks of CO2 not only requires highly accurate satellite instruments, but also puts stringent requirements on the performance of atmospheric transport models. Improving the accuracy of these models should receive high priority, which calls for a closer collaboration between experts in atmospheric dynamics and tracer transpor

Environmental factors influence both abundance and genetic diversity in a widespread bird species.

Genetic diversity is one of the key evolutionary variables that correlate with population size, being of critical importance for population viability and the persistence of species. Genetic diversity can also have important ecological consequences within populations, and in turn, ecological factors may drive patterns of genetic diversity. However, the relationship between the genetic diversity of a population and how this interacts with ecological processes has so far only been investigated in a few studies. Here, we investigate the link between ecological factors, local population size, and allelic diversity, using a field study of a common bird species, the house sparrow (Passer domesticus). We studied sparrows outside the breeding season in a confined small valley dominated by dispersed farms and small-scale agriculture in southern France. Population surveys at 36 locations revealed that sparrows were more abundant in locations with high food availability. We then captured and genotyped 891 house sparrows at 10 microsatellite loci from a subset of these locations (N = 12). Population genetic analyses revealed weak genetic structure, where each locality represented a distinct substructure within the study area. We found that food availability was the main factor among others tested to influence the genetic structure between locations. These results suggest that ecological factors can have strong impacts on both population size per se and intrapopulation genetic variation even at a small scale. On a more general level, our data indicate that a patchy environment and low dispersal rate can result in fine-scale patterns of genetic diversity. Given the importance of genetic diversity for population viability, combining ecological and genetic data can help to identify factors limiting population size and determine the conservation potential of populations

Phase Field Modeling of Fast Crack Propagation

We present a continuum theory which predicts the steady state propagation of cracks. The theory overcomes the usual problem of a finite time cusp singularity of the Grinfeld instability by the inclusion of elastodynamic effects which restore selection of the steady state tip radius and velocity. We developed a phase field model for elastically induced phase transitions; in the limit of small or vanishing elastic coefficients in the new phase, fracture can be studied. The simulations confirm analytical predictions for fast crack propagation.Comment: 5 pages, 11 figure

Orbital contribution to the magnetic properties of iron as a function of dimensionality

The orbital contribution to the magnetic properties of Fe in systems of decreasing dimensionality (bulk, surfaces, wire and free clusters) is investigated using a tight-binding hamiltonian in an $s, p,$ and $d$ atomic orbital basis set including spin-orbit coupling and intra-atomic electronic interactions in the full Hartree-Fock (HF) scheme, i.e., involving all the matrix elements of the Coulomb interaction with their exact orbital dependence. Spin and orbital magnetic moments and the magnetocrystalline anisotropy energy (MAE) are calculated for several orientations of the magnetization. The results are systematically compared with those of simplified hamiltonians which give results close to those obtained from the local spin density approximation. The full HF decoupling leads to much larger orbital moments and MAE which can reach values as large as 1$\mu_B$ and several tens of meV, respectively, in the monatomic wire at the equilibrium distance. The reliability of the results obtained by adding the so-called Orbital Polarization Ansatz (OPA) to the simplified hamiltonians is also discussed. It is found that when the spin magnetization is saturated the OPA results for the orbital moment are in qualitative agreement with those of the full HF model. However there are large discrepancies for the MAE, especially in clusters. Thus the full HF scheme must be used to investigate the orbital magnetism and MAE of low dimensional systems