2,539 research outputs found
Macrophage-sensory neuronal interaction in HIV-1 gp120-induced neurotoxicity
Acknowledgements We thank Dr Jim Perkins of University College London for his help with the statistical analysis of our gene array data. We thank Prof. Maria Papathanasopoulos from the University of the Witwatersrand, Johannesburg, for the gift of gp120Bal.Peer reviewedPublisher PD
Curved Gratings as Plasmonic Lenses for Linearly Polarised Light
The ability of curved gratings as sectors of concentric circular gratings to
couple linearly polarized light into focused surface plasmons is investigated
by theory, simulation and experiment. Curved gratings, as sectors of concentric
circular gratings with four different sector angles, are etched into a 30-nm
thick gold layer on a glass coverslip and used to couple linearly-polarised
free space light at nm into surface plasmons. The experimental and simulation
results show that increasing the sector angle of the curved gratings decreases
the lateral spotsize of the excited surface plasmons, resulting in focussing of
surface plasmons which is analogous to the behaviour of classical optical
lenses. We also show that two faced curved gratings, with their groove radius
mismatched by half of the plasmon wavelength (asymmetric configuration), can
couple linearly-polarised light into a single focal spot of concentrated
surface plasmons with smaller depth of focus and higher intensity in comparison
to single-sided curved gratings. The major advantage of these structures is the
coupling of linearly-polarised light into focused surface plasmons with access
to and control of the plasmon focal spot, which facilitates potential
applications in sensing, detection and nonlinear plasmonics.Comment: 15 pages and 12 figure
Annual Report of the Extension Division for the Year Ending June 30, 1920
The past year has been filled with unusual activity and interest along the different phases of agricultural extension work. The demand for the services of the different extension workers has greatly increased, so much so, that it has become a problem as to how their time may be best assigned so as to accomplish the most. Extension work is based upon cooperation. The counties, state and government cooperate in finding the problems and in solving them. Some of these agricultural and rural problems may be solved in the local community; others need the assistance of the whole county; other problems, again, are of a state-wide character and require the cooperation of all the counties. Again, there are other problems which are national in scope and which need the cooperation of all the states to bring about the proper solution. The counties, state and nation aim cooperate in the financing and in the planning of the work. The agricultural extension program has been carried out according to· the provisions of the South Dakota law enacted in 1915 and 1917, and aim in accordance with the federal Smith-Lever Act passed by Congress in 1914. The past year is the first one during which all of the farm bureau counties have cooperated and carried on extension work under our state law. During the two preceding years most of the counties in the state financed their agricultural extension work chiefly from emergency funds appropriated and furnished by the government
What is wrong with intelligent design?
While a great deal of abuse has been directed at intelligent design theory (ID), its starting point is a fact about biological organisms that cries out for explanation, namely “specified complexity” (SC). Advocates of ID deploy three kind of argument from specified complexity to the existence of a designer: an eliminative argument, an inductive argument, and an inference to the best explanation. Only the first of these merits the abuse directed at it; the other two arguments are worthy of respect. If they fail, it is only because we have a better explanation of SC, namely Darwin’s theory of evolution by natural selection
In defense of naturalism
History and the modern sciences are characterized by what is sometimes
called a “methodological naturalism” that disregards talk of divine agency. Some religious thinkers argue that this reflects a dogmatic materialism: a non-negotiable and a priori commitment to a materialist metaphysics. In response to this charge, I make a sharp distinction between procedural requirements and metaphysical commitments. The procedural requirement of history and the sciences—that proposed explanations appeal to publicly-accessible bodies of evidence—is non-negotiable, but has no metaphysical implications. The metaphysical commitment is naturalistic, but is both a posteriori and provisional, arising from the fact that for more than 400 years no proposed theistic explanation has been shown capable of meeting the procedural requirement. I argue that there is nothing to prevent religious thinkers from seeking to overturn this metaphysically naturalistic stance. But in order to do so they would need to show that their proposed theistic explanations are the best available explanations of a range of phenomena. Until this has been done, the metaphysical naturalism of history and the sciences remains defensible.Peer Reviewe
Automatic 3D bi-ventricular segmentation of cardiac images by a shape-refined multi-task deep learning approach
Deep learning approaches have achieved state-of-the-art performance in
cardiac magnetic resonance (CMR) image segmentation. However, most approaches
have focused on learning image intensity features for segmentation, whereas the
incorporation of anatomical shape priors has received less attention. In this
paper, we combine a multi-task deep learning approach with atlas propagation to
develop a shape-constrained bi-ventricular segmentation pipeline for short-axis
CMR volumetric images. The pipeline first employs a fully convolutional network
(FCN) that learns segmentation and landmark localisation tasks simultaneously.
The architecture of the proposed FCN uses a 2.5D representation, thus combining
the computational advantage of 2D FCNs networks and the capability of
addressing 3D spatial consistency without compromising segmentation accuracy.
Moreover, the refinement step is designed to explicitly enforce a shape
constraint and improve segmentation quality. This step is effective for
overcoming image artefacts (e.g. due to different breath-hold positions and
large slice thickness), which preclude the creation of anatomically meaningful
3D cardiac shapes. The proposed pipeline is fully automated, due to network's
ability to infer landmarks, which are then used downstream in the pipeline to
initialise atlas propagation. We validate the pipeline on 1831 healthy subjects
and 649 subjects with pulmonary hypertension. Extensive numerical experiments
on the two datasets demonstrate that our proposed method is robust and capable
of producing accurate, high-resolution and anatomically smooth bi-ventricular
3D models, despite the artefacts in input CMR volumes
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