4,676 research outputs found
Grid-connected renewables, storage and the UK electricity market
This article is a critical counterpoint to an article by published by Swift-Hook in the journal of Renewable Energy entitled "Grid-connected intermittent renewables are the last to be stored". In contrast to Swift-Hook we found evidence that "grid-connected intermittent renewables" have been, and will continue to be stored when it suits the "UK market" to do so. This article is important to policy makers as energy storage (through EV battery demand side management for example) may well have an important role to play in facilitating the integration of high wind penetrations
Learning Deep Similarity Metric for 3D MR-TRUS Registration
Purpose: The fusion of transrectal ultrasound (TRUS) and magnetic resonance
(MR) images for guiding targeted prostate biopsy has significantly improved the
biopsy yield of aggressive cancers. A key component of MR-TRUS fusion is image
registration. However, it is very challenging to obtain a robust automatic
MR-TRUS registration due to the large appearance difference between the two
imaging modalities. The work presented in this paper aims to tackle this
problem by addressing two challenges: (i) the definition of a suitable
similarity metric and (ii) the determination of a suitable optimization
strategy.
Methods: This work proposes the use of a deep convolutional neural network to
learn a similarity metric for MR-TRUS registration. We also use a composite
optimization strategy that explores the solution space in order to search for a
suitable initialization for the second-order optimization of the learned
metric. Further, a multi-pass approach is used in order to smooth the metric
for optimization.
Results: The learned similarity metric outperforms the classical mutual
information and also the state-of-the-art MIND feature based methods. The
results indicate that the overall registration framework has a large capture
range. The proposed deep similarity metric based approach obtained a mean TRE
of 3.86mm (with an initial TRE of 16mm) for this challenging problem.
Conclusion: A similarity metric that is learned using a deep neural network
can be used to assess the quality of any given image registration and can be
used in conjunction with the aforementioned optimization framework to perform
automatic registration that is robust to poor initialization.Comment: To appear on IJCAR
Performance of Spatial Modulation using Measured Real-World Channels
In this paper, for the first time real-world channel measurements are used to
analyse the performance of spatial modulation (SM), where a full analysis of
the average bit error rate performance (ABER) of SM using measured urban
correlated and uncorrelated Rayleigh fading channels is provided. The channel
measurements are taken from an outdoor urban multiple input multiple output
(MIMO) measurement campaign. Moreover, ABER performance results using simulated
Rayleigh fading channels are provided and compared with a derived analytical
bound for the ABER of SM, and the ABER results for SM using the measured urban
channels. The ABER results using the measured urban channels validate the
derived analytical bound and the ABER results using the simulated channels.
Finally, the ABER of SM is compared with the performance of spatial
multiplexing (SMX) using the measured urban channels for small and large scale
MIMO. It is shown that SM offers nearly the same or a slightly better
performance than SMX for small scale MIMO. However, SM offers large reduction
in ABER for large scale MIMO.Comment: IEEE Vehicular Technology Conference Fall 2013 (VTC-Fall 2013),
Accepte
Optimization and scale-up for commercialization of a novel synthesis of Triclosan
Please read the abstract in the section 00front of this documentDissertation (MSc (Applied Chemistry))--University of Pretoria, 2006.Chemistryunrestricte
First record of verticillium wilt (Verticillium longisporum) in winter oilseed rape in the UK
Verticillium longisporum is an important pathogen of oilseed rape (OSR) and vegetable brassicas in several European countries, but has not been reported previously in the UK (Karapapa et al., 1997; Steventon et al., 2002). In 2007, Verticillium wilt was suspected in UK crops of winter OSR (W-OSR) on cv. Castille in Romney Marsh, Kent and on cv. Barrel near Hereford. At these two locations, 32 and 10% of the plants, respectively, appeared to be affected, but the presence of stem canker may have masked some infections. Symptoms were first seen as the crops began to ripen (seeds green-brown to brown, Growth Stage: 6,4-6,5) and included brown and dark grey vertical bands on the stems from soil level into the branches, and premature ripening of some branches (Fig. 1).
Microsclerotia were observed on stem samples collected in the field (Fig. 2), suggesting V. longisporum as the causal agent. Cultures were prepared from field samples by immersing stem pieces in 5% sodium hypochlorite solution for one minute, washing twice in sterile distilled water and plating onto potato dextrose agar containing 25 mg/l streptomycin sulphate. Isolates from three plants per outbreak were identified morphologically as V. longisporum. Mean conidial dimensions (25 spores per isolate) were 8.80-9.65 μm (length) and 2.50-2.85 μm (width) and all isolates produced elongated microsclerotia, characters typical of V. longisporum (Karapapa et al., 1997). The identity was confirmed by PCR using species-specific primers (Steventon et al., 2002) and, as a member of the α sub-group, by direct sequencing of the amplicons from primer pairs ITS4-ITS5 and DB19-DB22 (Collins et al., 2003; 2005). Sequences for isolate 003 from Kent were deposited in GenBank (Accession Nos. HQ702376 and HQ702377). All isolates tested from 2008 and 2009 were identical with previously deposited sequences for European OSR isolates (e.g. AF363992 and AF363246 respectively). Pathogenicity was confirmed by inoculating three OSR cv. Castille seedlings per isolate using the root dip technique with 1 x 106 spores/ml (Karapapa et al., 1997) under heated glasshouse conditions at 19°C. Leaf yellowing and blackening of the leaf veins were found 26 days after inoculation (Fig. 3). Yellowing affecting the three oldest leaves increased for seven to nine days. After five weeks the final mean leaf area affected was 63-78% with no differences between isolates. No leaf yellowing occurred in the controls. After five weeks, V. longisporum was re-isolated from all the inoculated seedlings, but not from the non-inoculated controls.
In June 2008, infection of W-OSR crops in different fields on the same farms was found on cv. Es Astrid in Kent (56% incidence) and on cv. Lioness in Hereford (15% incidence). The Kent farm had been growing W-OSR alternating with winter wheat for at least 10 years whilst the Hereford farm had grown W-OSR one year in four. These short rotations of OSR may be contributing to the appearance of this disease. This study confirms the identification of V. longisporum on any host in the UK, through molecular studies and detailed spore measurements that were not reported in an earlier review (Gladders, 2009). This pathogen occurs in several European countries and, since OSR may be traded freely, following a Defra consultation, no statutory plant health action is to be taken
Late Light Curves of Normal Type Ia Supernovae
We present late-epoch optical photometry (BVRI) of seven
normal/super-luminous Type Ia supernovae: SN 2000E, SN 2000ce, SN 2000cx, SN
2001C, SN 2001V, SN 2001bg, SN 2001dp. The photometry of these objects was
obtained using a template subtraction method to eliminate galaxy light
contamination during aperture photometry. We show the optical light curves of
these supernovae out to epochs of up to ~640 days after the explosion of the
supernova. We show a linear decline in these data during the epoch of 200-500
days after explosion with the decline rate in the B,V,& R bands equal to about
1.4 mag/100 days, but the decline rate of the I-band is much shallower at 0.94
mag/100 days.Comment: 33 pages, 11 figures, Accepted for publication in The Astronomical
Journa
Sensitivity of the Quarantine Pest Rough Sweetpotato Weevil, Blosyrus asellus to Postharvest Irradiation Treatment
Rough sweetpotato weevil, Blosyrus asellus (Olivier), is a new quar- antine pest of Hawaii sweetpotatoes. Currently, sweetpotatoes can be exported from Hawaii to the U.S. mainland using a postharvest irradiation treatment of 150 Gy to control three other regulated insect pests. Studies were conducted to deter- mine whether this current radiation dose will also control any rough sweetpotato weevils in export shipments. Adult weevils were treated at various levels between 25 to 125 Gy and egg laying and egg hatch were measured. Rough sweetpotato weevil was found to be highly susceptible to irradiation, with no egg hatch at any radiation dose, even 25 Gy, the lowest dose tested. Results suggest that the 150 Gy irradiation treatment should be sufficient for control of rough sweetpotato weevil in Hawaii sweetpotatoes
Tattoo ink nanoparticles in skin tissue and fibroblasts
YesTattooing has long been practised in various societies all around the world and is becoming increasingly common and widespread
in the West. Tattoo ink suspensions unquestionably contain pigments composed of nanoparticles, i.e., particles of sub-100 nm
dimensions. It is widely acknowledged that nanoparticles have higher levels of chemical activity than their larger particle equivalents.
However, assessment of the toxicity of tattoo inks has been the subject of little research and ink manufacturers are not obliged
to disclose the exact composition of their products. This study examines tattoo ink particles in two fundamental skin components at
the nanometre level. We use atomic force microscopy and light microscopy to examine cryosections of tattooed skin, exploring the
collagen fibril networks in the dermis that contain ink nanoparticles. Further, we culture fibroblasts in diluted tattoo ink to explore
both the immediate impact of ink pigment on cell viability and also to observe the interaction between particles and the cells
Correcting for the Ewald Sphere in High-Resolution Single-Particle Reconstructions
To avoid the challenges of crystallization and the size limitations of NMR, it has long been hoped that single-particle cryo-electron microscopy (cryo-EM) would eventually yield atomically interpretable reconstructions. For the most favorable class of specimens (large icosahedral viruses), one of the key obstacles is curvature of the Ewald sphere, which leads to a breakdown of the Projection Theorem used by conventional three-dimensional (3D) reconstruction programs. Here, we review the basic problem and our implementation of the “paraboloid” reconstruction method, which overcomes the limitation by averaging information from images recorded from different points of view
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