Increasing yield and profit by straight-cutting canola

Non-Peer ReviewedStraight combining canola (Brassica napus) can save producers time, fuel costs, and equipment wear. Research was undertaken at three locations to determine if straight combining shatter losses would be reduced sufficiently with higher yield potential to make straight combining viable in western Canada. This research employed a randomized complete block design. Treatments included crop density (low and high), fertility (low and high), time of weed removal (early and late), and harvest time (early and late). Factors were selected to offer a range of yields to evaluate the relationship between potential yield and shatter loss. Overall, factors causing shatter loss and crop yield differed between locations. Not surprisingly, crop density was affected by target crop density and percent green seed was affected by harvest timing

Increasing yield and profit by straight-cutting canola

Non-Peer ReviewedStraight combining canola (Brassica napus) can save producers time, fuel costs, and equipment wear. Research was undertaken at three locations to determine if straight combining shatter losses would be reduced sufficiently with higher yield potential to make straight combining viable in western Canada. This research employed a randomized complete block design. Treatments included crop density (low and high), fertility (low and high), time of weed removal (early and late), and harvest time (early and late). Factors were selected to offer a range of yields to evaluate the relationship between potential yield and shatter loss. Different components of potential yield were important in determining yield and seed losses before and during harvest operations. In Lacombe, fertility has been the most important factor. In Vegreville, timing of weed removal was paramount in 2006. At Scott in 2006, it appears that all operations must be conducted under best management practices or there is a substantially increased probability of reduced yield when straight-cutting. These results generally fit the hypothesis that ability to straight-cut is dependent upon maximizing potential yield. Under higher-yielding conditions, a key factor has led to success at straight-cutting. Under low-yielding conditions, all factors contributing to increased potential yield must be used to ensure feasibility of straight-cutting

ARMOURED SCALE INSECTS (HEMIPTERA: COCCOIDEA: DIASPIDIDAE) NEW TO SICILY: RECORDS AND OBSERVATIONS

ARMOURED SCALE INSECTS (HEMIPTERA: COCCOIDEA: DIASPIDIDAE) NEW TO SICILY: RECORDS AND OBSERVATIONS. The central location of Sicily in the Mediterranean basin makes studies of its fauna particularly interesting. Recent collections from the scrub vegetation on the South-East coast of Sicily and the slopes of Mount Etna have produced four new records of Diaspididae for Sicily: Aonidia ?mediterranea (Lindinger), Ferreroaspis hungarica (Vinis), Mercetaspis isis (Hall) and Chionaspis etrusca Leonardi. The presence of the first three species suggests old faunistic links with other regions, mainly eastern Mediterranean. Our findings are presented here in the hope of stimulating more such research. Key words: Callitris, Cupressus, Juniperus, Thuja, Tamarix, Acer, Cerasus, Carulaspis silvestrii, C. minima, C. juniperi, ecology, host reaction

Previewing distracters reduces their effective contrast

In a visual search task, when half the distracters are presented earlier than the remainder (‘previewed’), observers find the target item more efficiently than when all the items are presented together—the preview benefit. We measured psychometric functions for contrast increments on Gabors that were presented as a valid preview for subsequent search, and when they were a non-predictive (dummy) preview. Sensitivity to contrast increments was lower (rightwards shift of the psychometric function) on valid, compared to dummy previews. This is consistent with an account of the preview benefit in terms of active inhibition, equivalent to lowering the contrast of previewed items that are being actively ignored

HONEYDEW SUGARS ELIMINATED BY STIGMACOCCUS SP. NR. ASPER HEMPEL (HEMIPTERA: MARGARODIDAE) FEEDING ON LEGUMINOUS TREES IN BRAZIL.

HONEYDEW SUGARS ELIMINATED BY STIGMACOCCUS SP. NR ASPER HEMPEL (HEMIPTERA: MARGARODIDAE) FEEDING ON LEGUMINOUS TREES IN BRAZIL. The sooty mould coating the trunks of mature trees of Schizolobium excelsum in Brazil was found to be associated with honeydew being eliminated by an undescribed species of margarodid near Stigmacoccus asper Hempel. Analysis of the honeydew sugars by paper chromatography revealed a complex composition. The principal sugar was sucrose, but there were significant amounts of fructose, glucose and three components identified as di-, tri- and tetrasaccharides. The disaccharides were maltose, trehalose, trehalulose and a hexose-hexitol. The other, apparently novel, pair of oligosaccharides were composed of glucose(s) 1,4 linked to the glucose of sucrose. The sugar composition of the tree sap was also determined and found to be glucose and sucrose only. The findings, therefore, imply significant and novel metabolic transformations of sugars by the scale insect and/or its microbial symbionts. Key words: Xylococcinae, sexual reproduction, stigmatriose, stigmatetraose, Amazonia

Optimum design and testing of a postbuckled stiffened panel

The efficient, industrially used, linear elastic preliminary design software VICONOPT is employed to design a stiffened panel with a post-buckled reserve of strength. The initial buckling mode is a local skin mode in longitudinal compression with allowance being made for the effects of an initial overall imperfection. The resulting panel has been analyzed using the non-linear FE package ABAQUS and four laboratory specimens have been tested to failure. The similarity of the experimental failure with the VICONOPT and ABAQUS predictions suggests that VICONOPT can give a satisfactory preliminary design. While neither model matches completely the boundary conditions found in a real aircraft compression panel, it is suggested that the VICONOPT model may be a better representation than either the ABAQUS model or the experimental tests

Model based analysis of fMRI-data: Applying the sSoTS framework to the neural basic of preview search.

The current work aims to unveil the neural circuits under- lying visual search over time and space by using a model-based analysis of behavioural and fMRI data. It has been suggested by Watson and Humphreys [31] that the prioritization of new stimuli presented in our visual field can be helped by the active ignoring of old items, a process they termed visual marking. Studies using fMRI link the marking pro- cess with activation in superior parietal areas and the precuneus [4, 18, 27, 26]. Marking has been simulated previously using a neural-level ac- count of search, the spiking Search over Time and Space (sSoTS) model, which incorporates inhibitory as well as excitatory mechanisms to guide visual selection. Here we used sSoTS to help decompose the fMRI signals found in a preview search procedure, when participants search for a new target whilst ignoring old distractors. The time course of activity linked to inhibitory and excitatory processes in the model was used as a regres- sor for the fMRI data. The results showed that different neural networks were correlated with top-down excitation and top-down inhibition in the model, enabling us to fractionate brain regions previously linked to vi- sual marking. We discuss the contribution of model-based analysis for decomposing fMRI data

Electron localization : band-by-band decomposition, and application to oxides

Using a plane wave pseudopotential approach to density functional theory we investigate the electron localization length in various oxides. For this purpose, we first set up a theory of the band-by-band decomposition of this quantity, more complex than the decomposition of the spontaneous polarization (a related concept), because of the interband coupling. We show its interpretation in terms of Wannier functions and clarify the effect of the pseudopotential approximation. We treat the case of different oxides: BaO, $\alpha$-PbO, BaTiO$_3$ and PbTiO$_3$. We also investigate the variation of the localization tensor during the ferroelectric phase transitions of BaTiO$_3$ as well as its relationship with the Born effective charges

A weakly stable algorithm for general Toeplitz systems

We show that a fast algorithm for the QR factorization of a Toeplitz or Hankel matrix A is weakly stable in the sense that R^T.R is close to A^T.A. Thus, when the algorithm is used to solve the semi-normal equations R^T.Rx = A^Tb, we obtain a weakly stable method for the solution of a nonsingular Toeplitz or Hankel linear system Ax = b. The algorithm also applies to the solution of the full-rank Toeplitz or Hankel least squares problem.Comment: 17 pages. An old Technical Report with postscript added. For further details, see http://wwwmaths.anu.edu.au/~brent/pub/pub143.htm

Quintessential Maldacena-Maoz Cosmologies

Maldacena and Maoz have proposed a new approach to holographic cosmology based on Euclidean manifolds with disconnected boundaries. This approach appears, however, to be in conflict with the known geometric results [the Witten-Yau theorem and its extensions] on spaces with boundaries of non-negative scalar curvature. We show precisely how the Maldacena-Maoz approach evades these theorems. We also exhibit Maldacena-Maoz cosmologies with [cosmologically] more natural matter content, namely quintessence instead of Yang-Mills fields, thereby demonstrating that these cosmologies do not depend on a special choice of matter to split the Euclidean boundary. We conclude that if our Universe is fundamentally anti-de Sitter-like [with the current acceleration being only temporary], then this may force us to confront the holography of spaces with a connected bulk but a disconnected boundary.Comment: Much improved exposition, exponent in Cai-Galloway theorem fixed, axionic interpretation of scalar explained, JHEP version. 33 pages, 3 eps figure