The demand for seafood products on the global market is rising, particularly in Asia, as affluence and appreciation of the health benefits of seafood increase. This is coupled with a capture fishery that, at best, is set for stagnation... more
The demand for seafood products on the global market is rising, particularly in Asia, as affluence and appreciation of the health benefits of seafood increase. This is coupled with a capture fishery that, at best, is set for stagnation and, at worst, significant collapse. Global aquaculture is the fastest growing sector of the food industry and currently accounts for approximately 45.6% of the world's fish consumption. However, the rapid development of extensive and semi-extensive systems, particularly intensive marine-fed aquaculture, has resulted in worldwide concern about the potential environmental, economic, and social impacts of such systems. In recent years, there has been a significant amount of research conducted on the development of sustainable saltwater-based food production systems through mechanical (e.g., recirculatory aquaculture (RAS) systems) methods and ecosystem-based approaches (e.g., integrated multi-trophic aquaculture (IMTA)). This review article will examine the potential negative impacts of monocultural saltwater aquaculture operations and review established (RAS) and novel (IMTA; constructed wetlands; saltwater aquaponics) saltwater-based food production systems and discuss their (potential) contribution to the development of sustainable and environmentally-friendly systems.
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Changes in community structure of an intertidal, macrobenthic community in the vicinity of a Crassostrea gigas (Thunberg) cultivation site were studied. Samples were taken underneath trestles, in access lanes and at a control site. No... more
Changes in community structure of an intertidal, macrobenthic community in the vicinity of a Crassostrea gigas (Thunberg) cultivation site were studied. Samples were taken underneath trestles, in access lanes and at a control site. No evidence of organic enrichment was found, linked to the highly dissipative nature of the study site, the latter as evidenced by the granulometric composition of the substrate and the species encountered. Compared to the community at a control site, the macrofauna in the access lanes has undergone species displacements and changes in numerical abundance of surficial living forms and shallow, fragile burrowers. This is postulated to be linked to physical disturbance by heavy vehicle traffic.
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There is a pressing need to protect the ecology of nearshore marine habitats that are used for an ever increasing range of activities. In particular, fisheries managers need to consider both environmental and socioeconomic issues in... more
There is a pressing need to protect the ecology of nearshore marine habitats that are used for an ever increasing range of activities. In particular, fisheries managers need to consider both environmental and socioeconomic issues in coastal areas owing to the environmental changes that can occur as a result of cultivation and harvesting processes associated with mariculture. Bivalve cultivation can be broadly split into three main processes: (1) seed collection, (2) seed nursery and on-growing, (3) harvesting. The environmental impacts of each cultivation stage will vary depending on the species in question and the techniques used. In many instances, commercial species are reared as seed in hatcheries prior to seeding, with few effects on the environment. However, while some species are collected from the wild using benign techniques such as spat collectors, others are extracted using intrusive devices such as dredges. A growing number of studies of the ecological effects of mechani...
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... of 0-9 and gross productivity was calculated assuming a photosynthetic quotient (pQ) of 1-5. Although Strickland & Parsons ... the identifiable flagellates which were present Platymonas spp., Cryptomonas spp., Eutreptiella sp.,... more
... of 0-9 and gross productivity was calculated assuming a photosynthetic quotient (pQ) of 1-5. Although Strickland & Parsons ... the identifiable flagellates which were present Platymonas spp., Cryptomonas spp., Eutreptiella sp., Dinobryon sp., and Prasinocladus marinus were the ...
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... Despite increased recent research activity, important gaps in the knowledge of the biology of L. forbesi remain, including accurate estimations of age and growth. Cephalopods are typically short-lived and semelparous (Forsythe &... more
... Despite increased recent research activity, important gaps in the knowledge of the biology of L. forbesi remain, including accurate estimations of age and growth. Cephalopods are typically short-lived and semelparous (Forsythe & Van Heukelem, 1987) and the estimation of ...
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... Galway. Thanks too to Dr T. Cross for critically reading the manuscript. ... Population genetics of marine pelecypods. IV. Selection, migration and genetic differentiation in the blue mussel Mytilus edulis. Evolution, 30, 2-32.... more
... Galway. Thanks too to Dr T. Cross for critically reading the manuscript. ... Population genetics of marine pelecypods. IV. Selection, migration and genetic differentiation in the blue mussel Mytilus edulis. Evolution, 30, 2-32. MATHERS, NF, 1975. ...
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ABSTRACT p1 Present address: Department of Zoology, University of Aberdeen, Tillydrone Avenue, Aberdeen, AB9 2TN.
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... for Reseeding Programmes Iris wernefiB, Stefan ~lothmann' and Gavin urn ell* quacu ... species. These two distributions were compared by means of the Brandt-Snedecor multiple-contingency-table X2 test (df = 6, P 5 0.05) (Sachs... more
... for Reseeding Programmes Iris wernefiB, Stefan ~lothmann' and Gavin urn ell* quacu ... species. These two distributions were compared by means of the Brandt-Snedecor multiple-contingency-table X2 test (df = 6, P 5 0.05) (Sachs 1984). ...
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... SISSEL ANDERSEN1∗, GAVIN BURNELL2 and ØIVIND BERGH3 1Institute of Marine Research, Austevoll Aquaculture Research Station, N-5392 Storebø, Norway ... Taylor, JE, Gunn, B., Williams, P. and McNicoll, I. (1994) An investigation of... more
... SISSEL ANDERSEN1∗, GAVIN BURNELL2 and ØIVIND BERGH3 1Institute of Marine Research, Austevoll Aquaculture Research Station, N-5392 Storebø, Norway ... Taylor, JE, Gunn, B., Williams, P. and McNicoll, I. (1994) An investigation of techniques for the hatchery and ...
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Page 1. Cephalopod Biodiversity, Ecology and Evolution Payne, AIL, Lipiftski, MR, Clarke, MR and MAC Roeleveld (Eds). S.Aft: 1. mar. Sci. 20: 153-163 1998 153 THE DIET ANDECOLOGICAL IMPORTANCE OF ILLEX COINDETII ...
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Next-generation concepts for solid-state memory devices are based on current-driven domain wall propagation, where the wall velocity governs the device performance. It has been shown that the domain wall velocity and the direction of... more
Next-generation concepts for solid-state memory devices are based on current-driven domain wall propagation, where the wall velocity governs the device performance. It has been shown that the domain wall velocity and the direction of travel is controlled by the nature of the wall and its chirality. This chirality is attributed to effects emerging from the lack of inversion symmetry at the interface between a ferromagnet and a heavy metal, leading to an interfacial Dzyaloshinskii-Moriya interaction that can control the shape and chirality of the magnetic domain wall. Here we present direct imaging of domain walls in Pt/Co/AlO$_x$ films using Lorentz transmission electron microscopy, demonstrating the presence of homochiral, and thus topologically protected, N\'{e}el walls. Such domain walls are good candidates for dense data storage, bringing the bit size down close to the limit of the domain wall width.
... Large low-field magnetoresistance in La 0.7 Ca 0.3 MnO 3 induced by artificial grain boundaries. ND Mathur * , G. Burnell * , SP Isaac * , TJ Jackson * , B.-S. Teo * , JL MacManus-Driscoll , LF Cohen , JE Evetts * & MG... more
... Large low-field magnetoresistance in La 0.7 Ca 0.3 MnO 3 induced by artificial grain boundaries. ND Mathur * , G. Burnell * , SP Isaac * , TJ Jackson * , B.-S. Teo * , JL MacManus-Driscoll , LF Cohen , JE Evetts * & MG Blamire *. ... | Article | ISI | ChemPort |; Sun, JZ et al. ...
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Andreev reflection Spectroscopy is a well established method to measure the transport spin-polarization in magnetic films. Here we discuss the prospects for using planar Andreev junctions to detect spin accumulation in the non-magnetic... more
Andreev reflection Spectroscopy is a well established method to measure the transport spin-polarization in magnetic films. Here we discuss the prospects for using planar Andreev junctions to detect spin accumulation in the non-magnetic semiconductor InAs. Here we compare Andreev spectra from planar fabricated Pb/InAs junctions and point-contact measurements. Planar junctions yield considerably lower smearing than point-contacts but the barrier parameter
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The transport properties of sharp antiferromagnetic boundaries between Gd and Fe have been studied. The measurements were carried out with the current perpendicular to the plane at 20 K and up to 8 T in multilayer Gd/Fe of different... more
The transport properties of sharp antiferromagnetic boundaries between Gd and Fe have been studied. The measurements were carried out with the current perpendicular to the plane at 20 K and up to 8 T in multilayer Gd/Fe of different thicknesses. We have extended the Valet ...
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We report the fabrication and measurement of Corbino geometry superconductornormal metalsuperconductor Josephson junctions. A circular junction barrier is defined in a superconductornormal metal bilayer and bias current flows through... more
We report the fabrication and measurement of Corbino geometry superconductornormal metalsuperconductor Josephson junctions. A circular junction barrier is defined in a superconductornormal metal bilayer and bias current flows through the device in the ...
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We have recently developed a technique for fabricating SNS junctions in MgB2 thin films using a focused ion beam. These junctions show a strong modulation of the critical current by applied magnetic field and microwaves. They also show... more
We have recently developed a technique for fabricating SNS junctions in MgB2 thin films using a focused ion beam. These junctions show a strong modulation of the critical current by applied magnetic field and microwaves. They also show large IcRN products in excess of 1 mV at 4.2 K making them attractive candidates for a range of superconducting electronics applications.
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ABSTRACT Josephson junction oscillators provide a means to determine the dielectric constant (εR) and its frequency, temperature and electric field dependence (εR(ω,T,E)) in thin-film dielectrics in the frequency range 100–900 GHz. Here,... more
ABSTRACT Josephson junction oscillators provide a means to determine the dielectric constant (εR) and its frequency, temperature and electric field dependence (εR(ω,T,E)) in thin-film dielectrics in the frequency range 100–900 GHz. Here, we have applied this technique to a 150 nm thick SrTiO3 (STO) film and found a variation in εR at 4.2 K from 363 ± 5 at one end of the sample to 150 ± 6 at the other end and in the absence of external bias voltage V across the STO. On application of such a bias, the εR of the film at 4.2 K was found to change by 30%. The maximum in εR(V) was found to be at −1 V instead of the expected 0 V, indicating the presence of an internal electric field in the STO layer, which we attribute to the difference in work functions of the gold and YBa2Cu3O7 electrodes in our structure. εR(T) was markedly different to that of bulk STO. In our thin film, εR(T) has a broad shoulder in which the temperature dependence is small between about 35 and 50 K, above which it rises again.
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We have developed a fabrication method using a focused ion beam microscope that allows us to produce SNS junctions in which thermally energetic electrons can enter the N region. We report on SQUIDs made with this technique which we are... more
We have developed a fabrication method using a focused ion beam microscope that allows us to produce SNS junctions in which thermally energetic electrons can enter the N region. We report on SQUIDs made with this technique which we are developing as proof of concept devices and prototype high energy resolution spectrometers. We discuss the various design parameters used for
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We measured the transport behavior of Ni80Fe20(Py)/Cu/Py current-perpendicular-to-plane (CPP) submicron spin-valve devices with Cu spacer thickness up to 530 nm, fabricated directly from as-grown heterostructures using a three-dimensional... more
We measured the transport behavior of Ni80Fe20(Py)/Cu/Py current-perpendicular-to-plane (CPP) submicron spin-valve devices with Cu spacer thickness up to 530 nm, fabricated directly from as-grown heterostructures using a three-dimensional focused-ion beam etching technique. The work bridged the gap between existing conventional CPP giant magnetoresistance measurements and lateral type spin-valve experiments. By fitting the data with the Valet-Fert model, we determined the spin asymmetry ratio of 0.80±0.01 and spin diffusion length of 600±245 nm in Cu at 77 K. The magnitude of resistance change obtained in this work was comparable with conventional CPP measurements, but was about two orders of magnitude larger than those of lateral spin-valve devices. The results implied that any success in exploiting the lateral type spintronic devices for practical uses would rely critically on improving the size of the measured signals.
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... Hence, it can be shown that to achieve a linear variation of dF with , one programs the speed at and t, V t, of the deposition according to VF ViVf Vf − Vi ViVf Vf − Vi − 2 −1 , 1 where Vi and Vf are the initial and final chip speeds,... more
... Hence, it can be shown that to achieve a linear variation of dF with , one programs the speed at and t, V t, of the deposition according to VF ViVf Vf − Vi ViVf Vf − Vi − 2 −1 , 1 where Vi and Vf are the initial and final chip speeds, respec-tively, in units of rpm. ...
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ABSTRACT A technique for the structural and electronic characterization of the same individual single wall carbon nanotube is presented. Electron diffraction was performed on carbon nanotubes grown across a perforated silicon nitride film... more
ABSTRACT A technique for the structural and electronic characterization of the same individual single wall carbon nanotube is presented. Electron diffraction was performed on carbon nanotubes grown across a perforated silicon nitride film and the chiral indices of individual tubes were determined. By means of a scanning-probe-based nanomanipulator a selected tube was then placed in the desired location across prepatterned electrodes. After patterning further electrodes on-top of the tube electronic transport measurements showed room temperature conductances of up to 0.2 G0. The application of a gate voltage allowed the tuning of the room temperature conductance of the device and measurements at liquid helium temperatures showed signatures of a Coulomb blockade, indicating the formation of a carbon nanotube quantum dot.
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ABSTRACT The capacitance of 24°[001] tilt calcium doped Y1-xCaxBa2Cu3O7-delta grain boundaries has been measured for thin films with x in the range 0.0-0.3 . The capacitance was determined from the hysteresis in the I-V characteristic. By... more
ABSTRACT The capacitance of 24°[001] tilt calcium doped Y1-xCaxBa2Cu3O7-delta grain boundaries has been measured for thin films with x in the range 0.0-0.3 . The capacitance was determined from the hysteresis in the I-V characteristic. By measuring the capacitance as a function of the voltage across the junctions it was possible to observe the contribution of both parasitic substrate capacitance and heating to the hysteresis. These effects enable the determination of the intrinsic capacitance of the grain boundaries. The effect of thermal noise on the measurement is also assessed, and found to be much less than the observed changes in the capacitance. The capacitance is found to increase as the calcium doping increases: from 0.2Fm-2 for x=0.0 to a maximum of 1.2Fm-2 for x=0.3 . The changes in the capacitance per unit area are observed to be inversely proportional to the corresponding changes in the resistance area product.
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We have performed current perpendicular-to-plane measurements in Gd-transition metal multilayers and amorphous Cox Gd1-x / Coy Gd1-y bilayers. Both systems create in-plane exchange spring domain walls (SWs) whose width can be controlled... more
We have performed current perpendicular-to-plane measurements in Gd-transition metal multilayers and amorphous Cox Gd1-x / Coy Gd1-y bilayers. Both systems create in-plane exchange spring domain walls (SWs) whose width can be controlled by an external magnetic field. The results can be explained fully by Lorentz magnetoresistance (MR) plus the effect of the interface. They show no intrinsic scattering from the
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Page 1. Fabrication of nanoscale heterostructure devices with a focused ion beam microscope This article has been downloaded from IOPscience. ... PII: S0957-4484(03)59080-8 Fabrication of nanoscale heterostructure devices with a focused... more
Page 1. Fabrication of nanoscale heterostructure devices with a focused ion beam microscope This article has been downloaded from IOPscience. ... PII: S0957-4484(03)59080-8 Fabrication of nanoscale heterostructure devices with a focused ion beam microscope ...
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The electrical properties of single walled carbon nanotubes are strongly dependent on their precise atomic configuration and as such it is of great importance to be able to fabricate devices containing individual carbon nanotubes of known... more
The electrical properties of single walled carbon nanotubes are strongly dependent on their precise atomic configuration and as such it is of great importance to be able to fabricate devices containing individual carbon nanotubes of known structure. We have developed a novel technique that allows for the determination of the chiral indices of an individual carbon nanotube followed by the