1,799 research outputs found
Technological and pedagogical convergence between work-based and campus-based learning
There is a strong technological and economic push for higher education providers to adopt online learning strategies. This is driven, in part, by the requirement of industry for lifelong learning on a flexible, just-in-time basis. Simultaneously, there is a rising awareness amongst engineering faculty of the pedagogical issues that underpin good teaching and learning practice, stimulated by revised accreditation approaches and related reviews. These significant drivers of change are often experienced as discordant if not competing issues. This paper presents a case study of work-integrated learning that parallels traditional on-campus learning. Technology and pedagogy begin to converge when: (1) pedagogical assumptions are identified early; (2) flexible learning is not confused with on-line learning; (3) intrinsic and external motivations of stakeholders are aligned; (4) there is broad ownership; and (5) a sustainable development strategy is adopted
Producers' Use of Crop Borders for Management of Potato Virus Y (PVY) in Seed Potatoes
Potato virus Y (PVY) is a very serious problem throughout most major seed potato producing states. Seed potato producers in Minnesota and North Dakota were surveyed in early 2005 to assess their perception of the profitability and risks associated with using crop borders to manage PVY in seed lots. Five of the 23 producers responding (a 25% response rate) said they had used crop borders in 2004. These 23 producers entered 152 seed lots into state seed certification programs. On average, producers had less than 0.1 seed lots rejected for PVY based on summer inspection. The average number of seed lots rejected in winter trials was 1.7. Of the 152 seed lots, these producers said they had entered into state seed certification programs, they reported detailed information on 108 lots. Generations 1 and 2 were the most likely generations to be protected by a crop border. Of these 108 seed lots, 104 passed summer inspection for PVY. Seventy-four percent of the 89 lots sent in for the winter test were reported to have passed. The use of crop borders was significant in explaining whether a seed lot had passed the winter test or not. Thirty-one (97%) of the 32 seed lots that were planted within a crop border passed the winter test while 31 (54%) of the 57 seed lots that were not planted with a crop border passed the winter test. No relationship was found between the choice of border crop and passing the winter test. Producers also were asked to state their agreement or disagreement with several statements regarding their knowledge and opinions on use of crop borders.Crop Production/Industries,
Simulation of fluid flows during growth of organic crystals in microgravity
Several counter diffusion type crystal growth experiments were conducted in space. Improvements in crystal size and quality are attributed to reduced natural convection in the microgravity environment. One series of experiments called DMOS (Diffusive Mixing of Organic Solutions) was designed and conducted by researchers at the 3M Corporation and flown by NASA on the space shuttle. Since only limited information about the mixing process is available from the space experiments, a series of ground based experiments was conducted to further investigate the fluid dynamics within the DMOS crystal growth cell. Solutions with density differences in the range of 10 to the -7 to 10 to the -4 power g/cc were used to simulate microgravity conditions. The small density differences were obtained by mixing D2O and H2O. Methylene blue dye was used to enhance flow visualization. The extent of mixing was measured photometrically using the 662 nm absorbance peak of the dye. Results indicate that extensive mixing by natural convection can occur even under microgravity conditions. This is qualitatively consistent with results of a simple scaling analysis. Quantitave results are in close agreement with ongoing computational modeling analysis
Spin squeezing in nonlinear spin coherent states
We introduce the nonlinear spin coherent state via its ladder operator
formalism and propose a type of nonlinear spin coherent state by the nonlinear
time evolution of spin coherent states. By a new version of spectroscopic
squeezing criteria we study the spin squeezing in both the spin coherent state
and nonlinear spin coherent state. The results show that the spin coherent
state is not squeezed in the x, y, and z directions, and the nonlinear spin
coherent state may be squeezed in the x and y directions.Comment: 4 pages, 2 figs, revised version submitted to J. Opt.
Single-dose benzathine penicillin in infants at risk of congenital syphilis : results of a randomised study
OBJECTIVE: To determine the efficacy of single-dose benzathine penicillin G in infants at high risk of congenital syphilis. DESIGN: Randomised study comparing benzathine penicillin with no therapy. SETTING: Peninsula Maternal and Neonatal Service, Cape Town. SUBJECTS: Asymptomatic infants born to mothers with untreated syphilis whose VDRL titre was 32 or more. OUTCOME MEASURES: The number of cases of congenital syphilis was determined by results of IgM Western blots and follow-up VDRL titres. RESULTS AND CONCLUSIONS: Of 8 patients followed up in the non-treatment group, 4 had congenital syphilis while 0/11 had the disease (P = 0.035) in the group receiving benzathine penicillin. Although the exact failure rate is unknown, benzathine penicillin is effective in preventing symptomatic congenital syphilis when administered to high-risk newborns
ECONOMIC ANALYSIS OF USING A BORDER TREATMENT FOR REDUCING ORGANOPHOSPHATE USE IN SEED POTATO PRODUCTION
Recent research shows initial colonization of potato fields by winged green peach aphid is concentrated at field edges. This suggests that insecticides applied only to field margins during initial colonization would largely eliminate a colonizing aphid population, conserve natural enemies in the field center, and reduce insecticide use. To better understand the costs and benefits of reducing organophosphate use, the six participating growers were interviewed to ascertain their reason for participating and their satisfaction with the border only treatment method as well as their estimated net economic benefits. Five of the farms ranked cost reduction as the most important reason for participating. The sixth farm ranked reducing virus spread as the most important reason with cost reduction as their second most important reason. The average cost savings over all 28 participating fields of using the border treatment is estimated to be $23.85 per acre for the entire field-a 93% savings. Almost all the farmers found the border treatment method to be successful at aphid control. None of the farmers observed any impact on the physical yield of seed potato. All the fields were certified during the summer except for one of Farmer F's fields that was lost because of off type. In conclusion, the border treatment method seems likely to be adopted by many farmers since the potential cost saving is large and farmers dislike Monitor. However, some farmers may resist the method due to scouting requirements and costs. Also, farmers with fields that do not meet the uniformity requirements of the border treatment will not be successful in their use of the border method.Crop Production/Industries,
Genetic Algorithm with Optimal Recombination for the Asymmetric Travelling Salesman Problem
We propose a new genetic algorithm with optimal recombination for the
asymmetric instances of travelling salesman problem. The algorithm incorporates
several new features that contribute to its effectiveness: (i) Optimal
recombination problem is solved within crossover operator. (ii) A new mutation
operator performs a random jump within 3-opt or 4-opt neighborhood. (iii)
Greedy constructive heuristic of W.Zhang and 3-opt local search heuristic are
used to generate the initial population. A computational experiment on TSPLIB
instances shows that the proposed algorithm yields competitive results to other
well-known memetic algorithms for asymmetric travelling salesman problem.Comment: Proc. of The 11th International Conference on Large-Scale Scientific
Computations (LSSC-17), June 5 - 9, 2017, Sozopol, Bulgari
Nowhere to Hide: Radio-faint AGN in the GOODS-N field. I. Initial catalogue and radio properties
(Abridged) Conventional radio surveys of deep fields ordinarily have
arc-second scale resolutions often insufficient to reliably separate radio
emission in distant galaxies originating from star-formation and AGN-related
activity. Very long baseline interferometry (VLBI) can offer a solution by
identifying only the most compact radio emitting regions in galaxies at
cosmological distances where the high brightness temperatures (in excess of
K) can only be reliably attributed to AGN activity. We present the first
in a series of papers exploring the faint compact radio population using a new
wide-field VLBI survey of the GOODS-N field. The unparalleled sensitivity of
the European VLBI Network (EVN) will probe a luminosity range rarely seen in
deep wide-field VLBI observations, thus providing insights into the role of AGN
to radio luminosities of the order across cosmic
time. The newest VLBI techniques are used to completely cover an entire 7'.5
radius area to milliarcsecond resolutions, while bright radio sources ( mJy) are targeted up to 25 arcmin from the pointing centre. Multi-source
self-calibration, and a primary beam model for the EVN array are used to
correct for residual phase errors and primary beam attenuation respectively.
This paper presents the largest catalogue of VLBI detected sources in GOODS-N
comprising of 31 compact radio sources across a redshift range of 0.11-3.44,
almost three times more than previous VLBI surveys in this field. We provide a
machine-readable catalogue and introduce the radio properties of the detected
sources using complementary data from the e-MERLIN Galaxy Evolution survey
(eMERGE).Comment: 15 pages, 8 figures, accepted in A&A. Machine-readable table
available upon reques
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