933 research outputs found
Insect pests and their control - Tobacco pests - Experiments in their control in Western Australia
Experiments have been conducted at Manjimup, Western Australia, for the control of insects attacking tobacco. The insects concerned include the leaf miner, stem borer, cutworms, looper caterpillars and grass hoppers.* The insecticides used were lead arsenate, DDT, dieldrin, aldrin and endrin. As applied, i.e., at equal intervals during the growing season and at the strengths used, DDT proved superior to all other treatments
Insect pests and their control - White wax scale (Ceroplastes destructor, Newstead)
The evaluation of control methods, the use of of organic insecticides and scale distribution on citrus trees in Western Australia.
Various treatments in white oil and white oil-soda sprays have been tested in western Australia against the white wax scale (Ceroplastes destructor, Newstead) which mainly attacks citrus trees. Reference has been previously made to this experiment (Jenkins, Shedley and Edwards, 1953
Domino: exploring mobile collaborative software adaptation
Social Proximity Applications (SPAs) are a promising new area for ubicomp software that exploits the everyday changes in the proximity of mobile users. While a number of applications facilitate simple file sharing between co–present users, this paper explores opportunities for recommending and sharing software between users. We describe an architecture that allows the recommendation of new system components from systems with similar histories of use. Software components and usage histories are exchanged between mobile users who are in proximity with each other. We apply this architecture in a mobile strategy game in which players adapt and upgrade their game using components from other players, progressing through the game through sharing tools and history. More broadly, we discuss the general application of this technique as well as the security and privacy challenges to such an approach
Diffusion of Technologies by the Tikonko Agricultural Extension Centre (TAEC) to Farmers of the Tikonko Chiefdom in Sierra Leone: Impacts, Problems, Proposed Solutions, and an Updated Outlook
Sierra Leone is a west African nation with about two-thirds of its population engaged in agriculture but it cannot feed itself. The country’s agricultural activities were disrupted by a decade-long Civil War that created a great need for improved farming technologies. The Tikonko Agricultural Extension Centre (TAEC) operates in the Tikonko Chiefdom to assist local farmers in improving food production through the fabrication of farm tools to be adopted and used by farmers. This study was conducted to investigate the impacts of the TAEC’s technologies on farmers and their communities in the Tikonko Chiefdom and identify problems and solutions associated with the technologies and their diffusion. The target population included farmers (N = 318) who used TAEC’s technologies and TAEC staff (N = 18) who were involved in the diffusion process. A majority of the farmers adopted and used TAEC’s technologies readily, which they perceived had considerable impact on their farming practices and communities. The relevance of TAEC’s technologies to farmers in Tikonko Chiefdom was also evident. However, the participating farmers and TAEC staff encountered numerous problems. A majority agreed that the diffusion and adoption process could be improved by increasing the farmers’ access to loans. Providing appropriate technologies that can be adopted by low income farmers stands to increase their productivity and self-reliance while improving their nations’ food security. It is undeniable that technologies contributing to food sufficiency and alleviating poverty are needed throughout the developing world; policymakers must be reminded of this condition continually
Are Topological Charge Fluctuations in QCD Instanton Dominated?
We consider a recent proposal by Horv\'ath {\em et al.} to address the
question whether topological charge fluctuations in QCD are instanton dominated
via the response of fermions using lattice fermions with exact chiral symmetry,
the overlap fermions. Considering several volumes and lattice spacings we find
strong evidence for chirality of a finite density of low-lying eigenvectors of
the overlap-Dirac operator in the regions where these modes are peaked. This
result suggests instanton dominance of topological charge fluctuations in
quenched QCD.Comment: LaTeX, 15 pages, 8 postscript figures, minor improvements, version to
appear in PR
Spin glass overlap barriers in three and four dimensions
For the Edwards-Anderson Ising spin-glass model in three and four dimensions
(3d and 4d) we have performed high statistics Monte Carlo calculations of those
free-energy barriers which are visible in the probability density
of the Parisi overlap parameter . The calculations rely on the
recently introduced multi-overlap algorithm. In both dimensions, within the
limits of lattice sizes investigated, these barriers are found to be
non-self-averaging and the same is true for the autocorrelation times of our
algorithm. Further, we present evidence that barriers hidden in dominate
the canonical autocorrelation times.Comment: 20 pages, Latex, 12 Postscript figures, revised version to appear in
Phys. Rev.
About the Functional Form of the Parisi Overlap Distribution for the Three-Dimensional Edwards-Anderson Ising Spin Glass
Recently, it has been conjectured that the statistics of extremes is of
relevance for a large class of correlated system. For certain probability
densities this predicts the characteristic large fall-off behavior
, . Using a multicanonical Monte Carlo technique,
we have calculated the Parisi overlap distribution for the
three-dimensional Edward-Anderson Ising spin glass at and below the critical
temperature, even where is exponentially small. We find that a
probability distribution related to extreme order statistics gives an excellent
description of over about 80 orders of magnitude.Comment: 4 pages RevTex, 3 figure
Determining the density of states for classical statistical models: A random walk algorithm to produce a flat histogram
We describe an efficient Monte Carlo algorithm using a random walk in energy
space to obtain a very accurate estimate of the density of states for classical
statistical models. The density of states is modified at each step when the
energy level is visited to produce a flat histogram. By carefully controlling
the modification factor, we allow the density of states to converge to the true
value very quickly, even for large systems. This algorithm is especially useful
for complex systems with a rough landscape since all possible energy levels are
visited with the same probability. In this paper, we apply our algorithm to
both 1st and 2nd order phase transitions to demonstrate its efficiency and
accuracy. We obtained direct simulational estimates for the density of states
for two-dimensional ten-state Potts models on lattices up to
and Ising models on lattices up to . Applying this approach to
a 3D spin glass model we estimate the internal energy and entropy at
zero temperature; and, using a two-dimensional random walk in energy and
order-parameter space, we obtain the (rough) canonical distribution and energy
landscape in order-parameter space. Preliminary data suggest that the glass
transition temperature is about 1.2 and that better estimates can be obtained
with more extensive application of the method.Comment: 22 pages (figures included
Diffusion and Localization of Cold Atoms in 3D Optical Speckle
In this work we re-formulate and solve the self-consistent theory for
localization to a Bose-Einstein condensate expanding in a 3D optical speckle.
The long-range nature of the fluctuations in the potential energy, treated in
the self-consistent Born approximation, make the scattering strongly velocity
dependent, and its consequences for mobility edge and fraction of localized
atoms have been investigated numerically.Comment: 8 pages, 11 figure
Allelochaeta (Sporocadaceae): Pigmentation lost and gained
The appendaged coelomycete genus Seimatosporium (Sporocadaceae, Sordariomycetes) and some of its purported synonyms Allelochaeta,Diploceras and Vermisporium are re-evaluated. Based on DNA data for five loci (ITS, LSU, rpb2, tub2 and tef1), Seimatosporium is shown to be paraphyletic. The ex-type species of Allelochaeta, Discostromopsis and Vermisporium represent a distinct sister clade to which the oldest name Allelochaeta is applied. These genera were traditionally separated based on a combination of conidial pigmentation, septation, and the nature of their conidial appendages. Allelochaeta is revealed to include taxa with both branched or solitary appendages, that could be cellular or continuous, with conidia being (2–)3(–5)-septate, hyaline, or pigmented, concolourous or versicolourous. This suggests that these characters should be applied at species, and not at the generic level. Conidial pigmentation appears to have been lost or gained several times during the evolution of species within Allelochaeta. In total, 25 new species, 15 new combinations, and 10 new epitypifications are proposed
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