Canker disease in Corymbia calophylla (Marri) in the south west of Western Australia

Cankering of marri in the southern forests of Western Australia is causing concern as it is increasing considerably in severity and geographic range. The contribution of canker fungi to stem, branch and tree death has not been studied in detail, and the causal agent(s) is yet to be determined (1). This project examined disease incidence and associated pathogens

Long Duration Exposure Facility (LDEF) structural verification test report

Structural load tests on the Long Duration Exposure Facility's (LDEF) primary structure were conducted. These tests had three purposes: (1) demonstrate structural adequacy of the assembled LDEF primary structure when subjected to anticipated flight loads; (2) verify analytical models and methods used in loads and stress analysis; and (3) perform tests to comply with the Space Transportation System (STS) requirements. Test loads were based on predicted limit loads which consider all flight events. Good agreement is shown between predicted and observed load, strain, and deflection data. Test data show that the LDEF structure was subjected to 1.2 times limit load to meet the STS requirements. The structural adequacy of the LDEF is demonstrated

Kinematics of the Broad Line Region in M81

A new model is presented which explains the origin of the broad emission lines observed in the LINER/Seyfert nucleus of M81 in terms of a steady state spherically symmetric inflow, amounting to 1 x 10^-5 Msun/yr, which is sufficient to explain the luminosity of the AGN. The emitting volume has an outer radius of ~1 pc, making it the largest broad line region yet to be measured, and it contains a total mass of ~ 5 x 10^-2 Msun of dense, ~ 10^8 cm^-3, ionized gas, leading to a very low filling factor of ~ 5 x 10^-9. The fact that the BLR in M81 is so large may explain why the AGN is unable to sustain the ionization seen there. Thus, the AGN in M81 is not simply a scaled down quasar.Comment: Accepted for Publication in ApJ 7/21/0

The relative compliance of energy-storing tendons may be due to the helical fibril arrangement of their fascicles

T.S. acknowledges funding for this work from the EPSRC through grant no. EP/L017997/1

Variations in solar wind fractionation as seen by ACE/SWICS over a solar cycle and the implications for Genesis Mission results

We use ACE/SWICS elemental composition data to compare the variations in solar wind fractionation as measured by SWICS during the last solar maximum (1999-2001), the solar minimum (2006-2009) and the period in which the Genesis spacecraft was collecting solar wind (late 2001 - early 2004). We differentiate our analysis in terms of solar wind regimes (i.e. originating from interstream or coronal hole flows, or coronal mass ejecta). Abundances are normalized to the low-FIP ion magnesium to uncover correlations that are not apparent when normalizing to high-FIP ions. We find that relative to magnesium, the other low-FIP elements are measurably fractionated, but the degree of fractionation does not vary significantly over the solar cycle. For the high-FIP ions, variation in fractionation over the solar cycle is significant: greatest for Ne/Mg and C/Mg, less so for O/Mg, and the least for He/Mg. When abundance ratios are examined as a function of solar wind speed, we find a strong correlation, with the remarkable observation that the degree of fractionation follows a mass-dependent trend. We discuss the implications for correcting the Genesis sample return results to photospheric abundances.Comment: Accepted for publication in Ap

CELLULAR DIFFERENTIATION OF THE IMMUNE SYSTEM OF MICE : VI. STRAIN DIFFERENCES IN CLASS DIFFERENTIATION AND OTHER PROPERTIES OF MARROW CELLS

Marrow cells and 5 x 107 thymocytes of unprimed (C57BL/6 x DBA/2)F1, (C57BL/10 x WB)F1 and (C3H x C57BL)F1 donor mice were mixed in vitro and transplanted into X-irradiated syngeneic hosts. Upon injection of sheep erythrocytes, splenic plaque-forming cells (PFC) secreting IgM (direct PFC or IgG (indirect PFC) hemolytic antibody were enumerated at the time of peak responses. By grading the numbers of marrow cells, inocula were found that contained few immunocompetent cells reaching the recipient spleens, interacting with thymocytes or other accessory cells (or both), and generating PFC. The frequency of responses in BDF1 mice conformed to Poisson statistics, indicating that immunocompetent marrow cells participated in a single-hit interaction limiting PFC responses. The marrow cells assayed were not restricted for the antibody class (IgM versus IgG) to be secreted by mature PFC. Unrestricted marrow cells could have been either the precursors of PFC or accessory cells. Different results were obtained in BWF1 and C3BF1 mice. The frequency of responses in relation to the number of marrow cells grafted did not follow Poisson statistics, and the limiting cells were restricted for antibody class. Presumably, immunocompetent cells of these strains were more heterogeneous than those of BDF1 mice and participated in a multiplicity of cell-to-cell interactions. The strain differences reflected inherent properties of marrow cells and not influences of the environment in which PFC were produced. The results confirmed for bone marrow the heterogeneity of immunocompetent cells reported by others for spleen, and suggested that genetic factors such as "immune response" genes regulate cellular differentiation also for functions other than those related to antibody specificity

A MERLIN Observation of PSR B1951+32 and its associated Plerion

In an investigative 16 hour L band observation using the MERLIN radio interferometric array, we have resolved both the pulsar PSR B1951+32 and structure within the flat spectral radio continuum region, believed to be the synchrotron nebula associated with the interaction of the pulsar and its `host' supernova remnant CTB 80. The extended structure we see, significant at $\sim$ 4.5 $\sigma$, is of dimensions 2.5" $\times$ 0.75", and suggests a sharp bow shaped arc of shocked emission, which is correlated with similar structure observed in lower resolution radio maps and X-ray images. Using this MERLIN data as a new astrometric reference for other multiwavelength data we can place the pulsar at one edge of the HST reported optical synchrotron knot, ruling out previous suggested optical counterparts, and allowing an elementary analysis of the optical synchrotron emission which appears to trail the pulsar. The latter is possibly a consequence of pulsar wind replenishment, and we suggest that the knot is a result of magnetohydrodynamic (MHD) instabilities. These being so, it suggests a dynamical nature to the optical knot, which will require high resolution optical observations to confirm.Comment: 12 pages, 2 figures. Accepted for publication in ApJ