174 research outputs found
Training and Establishment Survival
We investigate the relationship between training and the likelihood of commercial survival over a 7-year period, using a survey of British establishments. We find that in stablishments of 200 or more employees, increased training of those in Professional, Sales, and Clerical and Secretarial occupations is associated with a greater chance of survival. In smaller establishments of less than 200 employees, increased training for Operatives and Assembly workers, Personal and Protective Service workers, and Craft and Technical workers is associated with better chances of survival. We interpret these findings as suggesting that training for these groups generated above-normal returns and indicates under-investment in training by such firms. There is no evidence to suggest under-investment in management training.training, survival, economic performance
Application of Tube Fishways to Weirs
Hydraulic barriers such as weirs and dams impede the natural connectivity of riverine systems and severely disrupt the migratory behaviours of fish. Even small weirs can prevent upstream fish migration. The consequent reduction in freshwater fishes' habitat access have caused a global decline in fish populations. Fishways aim to enable migratory fish passage, however relatively few hydraulic barriers in Australia are fitted with a fishway. A review of common fish barriers and an evaluation of current fishway designs on weirs is presented. A novel fishway system, the Tube Fishway, which aims to address existing fishway shortcomings is described. This contribution discusses the diversity of weir types in Australia and potential approaches to the installation and operation of Tube Fishways on these structures. Field experiments to evaluate the effectiveness of Tube Fishway design, installation and operation are described
High-temperature dielectric ceramics of the tetragonal tungsten-bronze structure and the role of aerosol deposition in modulating permittivity-temperature relationships
This work explores the development of high temperature dielectrics based on an unfilled tungsten
bronze-structured ceramic, Ca0.28Ba0.72Nb2O6 (CBN28), for potential power electronics applications.
CBN28 exhibited ferroelectric P-E loops, a slightly diffuse permittivity peak around TC at 231 °C, and
high losses above 250 °C due to ionic conductivity (tan Ύ > 0.2). Subsequent A site substitution of Y3+
for Ca2+/Ba2+ with assumed vacancy addition, in the nominal composition (Ca0.28Ba0.72)1â3w/2YwNb2O6 [0 †w †0.20], increased permittivity-temperature stability at the single-phase limit, w = 0.04 (Ér = 1143 ±15 % from 71 to 210 â°C), and narrowed P-E loops (Pr at 40 kV cm-1 = 1.5 ”C cm-2, whereas in CBN28 Pr = 2.4 ”C cm-2). Doping with Y3+ and Ta5+, in the nominal composition (Ca0.28Ba0.72)0.94Y0.04Nb1.8Ta0.2O6, induced permittivity-frequency dependence, lowered the temperature of Ér-Max (TM) to 13 °C at 1 kHz and 46 °C at 1000 kHz, further improved temperature stability of permittivity (Ér = 954 ±15 % from -58 to 110 â°C) and substantially narrowed P-E loops (Pr at 40 kV cm-1 = ~0.5 ”C cm-2). Decreasing Ca content, in the formulation (Ca0.22Ba0.78)0.94Y0.04Nb1.8Ta0.2O6, produced Ér = 972 ±15 % from -9 to 166 â°C and removed a secondary phase.
To develop low-temperature deposition of strained ceramic films, a particle aerosol deposition (PAD)
system was commissioned at Leeds. This produced submicron Al2O3 and CBN28 anchor layer films with
evidence of severe ceramic deformation in the layers by electron microscopy. Subsequent PAD (on a
system in Manchester) of a calcined, high-energy milled and granulated CBN28 powder produced a
thick film (10+ ”m) with highly supressed polarisation responses (PMax at 40 kV cm-1 = ~0.3 ”C cm-2, Δr = ~85). Annealing, up to 750 °C, partially recovered permittivity, retained improved temperature
stability, and induced relaxor-like frequency dependence (Δr = ~225 ±15 % from ~20 to ~240 °C). XRD
peak broadening analysis of the CBN film pre- and post- annealing at 750 °C suggested microstrain
reduction from 0.14 to 0.11 % strain in combination with crystallite size increases from ~125 to ~270
nm
Polyploidy, infraspecific cytotype variation, and speciation in Goldenrods: The cytogeography of Solidago subsect. Humiles (Asteraceae) in North America
Polyploidy is an important evolutionary mechanism in plants, and in some genera (e.g., Solidago in Asteraceae) it is particularly widespread and is hypothesized to have played a major role in diversification. Goldenrods are notorious for their ploidy variation, with roughly 14% and 32% of recognized North American species being polyploid or including multiple cytotypes, respectively. We used traditional chromosome counts and flow cytometry to examine cytogeographic patterns, biogeographic and evolutionary hypotheses, and species boundaries in S. subsect. Humiles. Chromosome numbers and DNA ploidy determinations are reported for 337 individuals, including 148 new reports. Cytotypes show significant geographic structuring. Solidago simplex and S. spathulata were uniformly diploid (2n = 18) in western North America, while cytogeographic patterns in eastern North America were regionally complex and included 2n, 4n, and 6n cytotypes. Cytotypes within S. simplex were ecogeographically segregated and mixedâploidy populations were rare. Data from this study and additional biosystematic data indicate that cytotypes in S. simplex fulfill the requirements of multiple species concepts and should best be treated as distinct species. Polyploid cytotypes possibly formed recurrently, however, and evolution and species boundaries within poly ploid S. simplex will require additional study. Results from this study and accumulated data from other studies suggest that biological species diversity in Solidago is considerably higher than currently recognized taxonomically.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147108/1/tax611014-sup-001-PDF.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/147108/2/tax611014.pd
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Session B6: Seeking Better Fishways: the Pump Fishway Program
Abstract:
A surprising hiatus affects fish research and management. Those of us working in fish passage strive to move fish past barriers. Aquaculturists, on the other hand, move fish around fish farms safely and effectively. Marrying these two approaches presents an exciting opportunity for fishway development. Millions of fish-passage barriers remain in rivers globally, together with many under-performing and costly fishway investments, resulting in declining biodiversity and production of freshwater fish. Better approaches to fishway design are urgently needed to aid in halting this worldwide loss of connectivity.
Multidisciplinary work at UNSW Australia aims to refine and test a pump fishway. This novel concept integrates technologies from fish passage and aquaculture to improve fishway performance and reduce costs. Fishways knowledge is being combined with pumping techniques routinely used in aquaculture to safely transport large biomasses of fish from across a broad size range. The pump fishway uses a helical fishway section to provide sufficient elevation for fish to be gravitated into a transfer chamber, which is then pressurized with water piped from the reservoir. This flow carries fish up a rising transfer pipe and a small auxiliary pump finally delivers fish into the reservoir.
A pump fishway offers many potential benefits: effective upstream passage for migrant fish communities; lightweight, modular construction with few moving parts; applicability to diverse sites and barriers \u3e1.5 m high; energy-independence using hydraulic power from the reservoir to drive the system; continuous operation with brief transfer cycles; and potential barge-mounted use providing mobility, flood protection and fewer constraints due to tailwater levels. Large savings on capital and operating costs are predicted. Research and development are planned to optimise and validate the pump fishway design, using physical and computational hydraulic modelling and animal trials with wild, migrating fish
Session 2-1-E: Betting market efficiency implications of different structures: bookmakers vs. exchanges
Outline
(i) Quick definition of market efficiency
(ii) Theoretical models lead to general predictionsâŠ
(iii) ...which lead to specific predictions about betting markets
(iv) Results of testing the predictions using real betting market data
(v) Implications and conclusio
Lifting fish across barriers with the Tube Fishway: lessons from the laboratory
To transfer fish across barriers, fishways are commonly used. A multidisciplinary research team from UNSW Sydney, has made important progress on the operation of a new type of fishway, the Tube Fishway, under controlled conditions in the laboratory. Research has shown that fish can be successfully attracted into the Tube Fishway's transfer chamber, while an innovative lifting mechanism based upon an unsteady surge, has been introduced to avoid the use of a mechanical pump. Using this lifting mechanism, tests with juvenile Australian bass (Percalates novemaculeata) and silver perch (Bidyanus bidyanus) have shown that fish can be safely lifted in Tube Fishways with heights of 4 and 8 m. Replacing live fish with a neutrally buoyant sensor packet, has provided important guidance on the pressures and accelerations that fish would experience during operation of the Tube Fishway. Trials with an automated Tube Fishway have demonstrated the fully automated operation of the Tube Fishway paving the way for upcoming field installations of Tube Fishways. Important lessons from the laboratory experiments are discussed and future research needs addressed
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Proof of concept for an innovative pump fishway design to move fish upstream over dams
Reversing worldwide declines in freshwater fish while making sustainable use of water resources will require effective and economical fishways to restore fish migrations. Mitigation of barrier effects at dams and weirs is too often impeded by poor fishway performance and high costs, so that many fish migrations continue to be obstructed. Improved and less-costly designs are urgently needed. Our innovative pump fishway concept combines fish-behaviour insights, proved fishways techniques and aquacultureâs pumping methods for safe upstream transport of living fish. We ran a series of experimental trials using several scale-model fishway designs with young, hatchery-bred fish. Our horizontal-cylinder design successfully combined volitional-passage functions of existing fishways with non-volitional transport in a conduit carrying pumped water. Several key principles of fish behaviour in fishways led to design improvements: disturbed fish often seek refuge at depth; fishesâ escape reactions strongly motivate swimming into flows; and curved structures aid passage by reducing delays. Replicated trials finally produced an average of 98% successful passage, within brief cycling periods. The pump fishway concept offers potential for effective upstream fish passage at new and existing sites \u3e~2m high, with low construction and maintenance costs and highly adaptable operation in variable flow regimes. Development beyond the concept-trial phase is now a priority
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