Selection of Corymbia citriodora for pulp productivity

Evaluation of a series of spotted gum (Corymbia citirodora) progeny trials, established in the subtropical region of Queensland, Australia, was undertaken to provide information for the development of advanced-generation breeding populations suitable for pulp production. Measurements of growth at two ages were combined with assessments of wood density and pulp yield from a selected sample of provenances to provide comparisons between provenances, to generate genetic parameter estimates and to predict genetic gain potential. Although growth at this age was moderate relative to other eucalypts, the near-infrared predictions of average wood density of 756 kg m-3 and pulp yield of 55% indicate the species has considerable potential as a pulpwood crop. A pulp productivity breeding objective was used to identify production populations using a range of selection trait weightings to determine potential genetic gain for pulp productivity. Genetic parameters indicated (1) levels of genetic control were moderate for all traits and higher for wood property traits, (2) genetic improvements could be achieved by selection among and within provenances with greater levels of improvement available from selection within populations, (3) genotype by environment interactions were negligible, (4) genetic correlations between traits were favourable, and (5) selection of volume production alone would maximise improvements in pulp productivity

Ανάδειξη της αγροτικής παραγωγής στην αστική καθημερινότητα. _προβολή _ εμπόριο _ ενημέρωση στην Θήβα

An 'aggregate economic' value (H), which is a combination of genetic control and relative economic value of traits, for all traits in the breeding objective was developed to aid in multitrait selection of strawberry cultivars in the subtropical southeast Queensland program. A profitability index for 12 traits was calculated from the effect of unit changes in each trait on changes in production costs and profitability. The index was applied to the breeding values of 3008 genotypes to produce estimates of H. H was validated by its high correlation (R=0.77) with year of selection (1945-1998) for commercial cultivars. H values for 3008 genotypes ranged from -0.36 to +0.28, when the zero value was set to the value of the cultivar 'Festival', which is the main cultivar grown in southeast Queensland. Modelling indicated that the gross margins were highly linearly related (R0.98) to H values where the genotype occupied less than 50% of total area planted in the industry, but this relationship became quadratic when the genotype occupied higher percentages of the total area planted to strawberries, and variation in gross margin increased as H values increased. H is efficient in identifying economically superior genotypes, but, when deploying new genotypes with high H, impacts on farm gross margin due to high adoption rates should also be considered

Effect of voxel size in cone-beam computed tomography on surface area measurements of dehiscences and fenestrations in the lower anterior buccal region.

OBJECTIVES This study aims to assess whether different voxel sizes in cone-beam computed tomography (CBCT) affected surface area measurements of dehiscences and fenestrations in the mandibular anterior buccal region. MATERIALS AND METHODS Nineteen dry human mandibles were scanned with a surface scanner (SS). Wax was attached to the mandibles as a soft tissue equivalent. Three-dimensional digital models were generated with a CBCT unit, with voxel sizes of 0.200 mm (VS200), 0.400 mm (VS400), and 0.600 mm (VS600). The buccal surface areas of the six anterior teeth were measured (in mm2) to evaluate areas of dehiscences and fenestrations. Differences between the CBCT and SS measurements were determined in a linear mixed model analysis. RESULTS The mean surface area per tooth was 88.3 ± 24.0 mm2, with the SS, and 94.6 ± 26.5 (VS200), 95.1 ± 27.3 (VS400), and 96.0 ± 26.5 (VS600), with CBCT scans. Larger surface areas resulted in larger differences between CBCT and SS measurements (- 0.1 β, SE = 0.02, p < 0.001). Deviations from SS measurements were larger with VS600, compared to VS200 (1.3 β, SE = 0.05, P = 0.009). Fenestrations were undetectable with CBCT. CONCLUSIONS CBCT imaging magnified the surface area of dehiscences in the anterior buccal region of the mandible by 7 to 9%. The larger the voxel size, the larger the deviation from SS measurements. Fenestrations were not detectable with CBCT. CLINICAL RELEVANCE CBCT is an acceptable tool for measuring dehiscences but not fenestrations. However, CBCT overestimates the size of dehiscences, and the degree of overestimation depends on the actual dehiscence size and CBCT voxel size employed

Timing Noise in SGR 1806-20

We have phase connected a sequence of RXTE PCA observations of SGR 1806-20 covering 178 days. We find a simple secular spin-down model does not adequately fit the data. The period derivative varies gradually during the observations between 8.1 and 11.7 * 10^-11 s/s (at its highest, ~40% larger than the long term trend), while the average burst rate as seen with BATSE drops throughout the time interval. The phase residuals give no compelling evidence for periodicity, but more closely resemble timing noise as seen in radio pulsars. The magnitude of the timing noise, however, is large relative to the noise level typically found in radio pulsars. Combining these results with the noise levels measured for some AXPs, we find all magnetar candidates have \Delta_8 values larger than those expected from a simple extrapolation of the correlation found in radio pulsars. We find that the timing noise in SGR 1806-20 is greater than or equal to the levels found in some accreting systems (e.g., Vela X-1, 4U 1538-52 and 4U 1626-67), but the spin-down of SGR 1806-20 has thus far maintained coherence over 6 years. Alternatively, an orbital model with a period P_orb = 733 days provides a statistically acceptable fit to the data. If the phase residuals are created by Doppler shifts from a gravitationally bound companion, then the allowed parameter space for the mass function (small) and orbital separation (large) rule out the possibility of accretion from the companion sufficient to power the persistent emission from the SGR.Comment: 11 pages, accepted for publication in ApJ Letter

Sub-tropical exotic pine taxa, growth, form and wood properties comparisons across multiple sites in coastal Queensland in: thinning and clearfall age trials; in family and clonal hybrid pine trials and in a genetics x fertiliser x weed control trial.

This project supports improved management and deployment of sub-tropical pines for solid wood products. It had three major objectives, in respect of both growth rate and standing tree wood properties: 1) to compare major and potential pine species and hybrids for south-east Queensland; 2) to investigate selection strategies for identifying improved families and clones, and make selections; and, 3) to evaluate both the separate and combined effects of fertiliser application, weed control and genetic improvement in a young hybrid pine trial

Photometric observations of the radio bright B[e]/X-ray binary CI Cam

We present multiwavelength (optical, IR, radio) observations of CI Cam, the optical counterpart to the transient X-ray source XTE J0421+560. Pre-outburst quiescent observations reveal the presence of a dusty envelope around the system. Pronounced short term variability is observed at all wavebands from U-K, but no indication of prior flaring of a similar magnitude to the 1998 April outburst is found in these data. Data obtained during the 1998 April X-ray flare reveal pronounced optical-radio flaring. The optical flux was observed to quickly return to quiescent levels, while the radio flare was of much longer duration. The optical component is likely to result from a combination of free-free/free-bound emission, emission line and thermal dust emission, caused by re-radiation of the X-ray flux, while the behaviour of the multiwavelength radio data is consistent with emission from expanding ejecta emitting via the synchrotron mechanism. Post-outburst (1998 August-1999 March) U-M broadband photometric observations reveal that while the optical (UBV) flux remains at pre-outburst quiescent levels, near IR (JHKLM) fluxes exceed the pre-outburst fluxes by ~0.5 magnitudes. Modelling the pre- and post-outburst spectral energy distribution of CI Cam reveals that the structure and/or composition of the dusty component of the circumstellar envelope appears to have changed. Due to a lack of information on the precise chemical composition of the dust within the system several explanations for this behaviour are possible, such as the production of new dust at the inner edge of the envelope, or modification of the composition of the dust due to X-ray irradiation

Decrease in the orbital period of dwarf nova OY Carinae

We have measured the orbital light curve of dwarf nova OY Carinae on 8 separate occasions between 1997 September and 2005 December. The measurements were made in white light using CCD photometers on the Mt Canopus 1 m telescope. The time of eclipse in 2005 December was 168 +- 5 s earlier than that predicted by the Wood et al.(1989) ephemeris. Using the times of eclipse from our measurements and the compilation of published measurements by Pratt et al (1999) we find that the observational data are inconsistent with a constant period and indicate that the orbital period is decreasing by 5+-1 X 10^-12 s/s. This is too fast to be explained by gravitational radiation emission. It is possible that the change is cyclic with a period greater than about 80 years. This is much longer than typical magnetic activity cycles and may be due to the presence of a third object in the system. Preliminary estimates suggest that this is a brown dwarf with mass about 0.016 Msun and orbital radius >= 17 AU.Comment: 4 pages 2 figures. MNRAS submitted Final proofread version. Discussion modified with figure showing fits and residuals to models, statistical significance of fits added and minor typographical edit

Discovery of a New Soft Gamma Repeater, SGR 1627-41

We report the discovery of a new soft gamma repeater (SGR), SGR 1627-41, and present BATSE observations of the burst emission and BeppoSAX NFI observations of the probable persistent X-ray counterpart to this SGR. All but one burst spectrum are well fit by an optically thin thermal bremsstrahlung (OTTB) model with kT values between 25 and 35 keV. The spectrum of the X-ray counterpart, SAX J1635.8-4736, is similar to that of other persistent SGR X-ray counterparts. We find weak evidence for a periodic signal at 6.41 s in the light curve for this source. Like other SGRs, this source appears to be associated with a young supernova remnant G337.0-0.1. Based upon the peak luminosities of bursts observed from this SGR, we find a lower limit on the dipole magnetic field of the neutron star B_dipole > 5 * 10^14 Gauss.Comment: 5 pages, 4 figures, submitted to ApJ Letter