1,125 research outputs found
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In memoriam, Heinz Isler - shell builder and structural artist, 26 July 1926 - 20 June 2009
Representation results for defeasible logic
The importance of transformations and normal forms in logic programming, and
generally in computer science, is well documented. This paper investigates
transformations and normal forms in the context of Defeasible Logic, a simple
but efficient formalism for nonmonotonic reasoning based on rules and
priorities. The transformations described in this paper have two main benefits:
on one hand they can be used as a theoretical tool that leads to a deeper
understanding of the formalism, and on the other hand they have been used in
the development of an efficient implementation of defeasible logic.Comment: 30 pages, 1 figur
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Neural processing of imminent collision in humans
Detecting a looming object and its imminent collision is imperative to survival. For most humans, it is a fundamental aspect of daily activities such as driving, road crossing and participating in sport, yet little is known about how the brain both detects and responds to such stimuli. Here we use functional magnetic resonance imaging to assess neural response to looming stimuli in comparison with receding stimuli and motion-controlled static stimuli. We demonstrate for the first time that, in the human, the superior colliculus and the pulvinar nucleus of the thalamus respond to looming in addition to cortical regions associated with motor preparation. We also implicate the anterior insula in making timing computations for collision events
A versatile high resolution objective for imaging quantum gases
We present a high resolution objective lens made entirely from catalog
singlets that has a numerical aperture of 0.36. It corrects for aberrations
introduced by a glass window and has a long working distance of 35mm, making it
suitable for imaging objects within a vacuum system. This offers simple high
resolution imaging for many in the quantum gas community. The objective
achieves a resolution of 1.3{\mu}m at the design wavelength of 780nm, and a
diffraction-limited field of view of 360{\mu}m when imaging through a 5mm
window. Images of a resolution target and a pinhole show quantitative agreement
with the simulated lens performance. The objective is suitable for
diffraction-limited imaging on the D2 line of all the alkalis by changing only
the aperture diameter, retaining numerical apertures above 0.32. The design
corrects for window thicknesses of up to 15mm if the singlet spacings are
modified
Prevalence of plasma small dense LDL is increased in obesity in a Thai population
Background Plasma low density lipoprotein (LDL) particles vary in size, density, electrical charge and chemical composition. An increased presence of small dense LDL (sdLDL), along with raised triglyceride concentrations and decreased high density lipoprotein (HDL) cholesterol concentrations is commonly known as the atherogenic triad and has been observed in some cases of obesity, principally in Europe and America. This study examines the prevalence of sdLDL in the plasma of an obese (BMI ≥ 25 kg/m2) Thai population. Methods Plasma from fasted obese (n = 48) and non-obese (n = 16) Thai participants was subjected to density gradient ultracentrifugation in iodixanol to separate lipoproteins. Gradients were unloaded top-to-bottom into 20 fractions which were assayed for cholesterol, triglyceride, apo B and apo A-1 to identify lipoprotein types and subtypes. Results LDL cholesterol was subfractionated into LDL I + II (fractions 3–6, ρ = 1.021-1.033 g/ml) which was considered to represent large buoyant LDL (lbLDL), LDL III (fractions 7–9, ρ = 1.036-1.039 g/ml) which was considered to represent sdLDL, and, LDL IV (fractions 10–12, ρ = 1.044-1.051 g/ml) which was considered to represent very sdLDL. Concentrations of LDL III and IV were increased by 15-20% in obese participants whilst that of LDL I + II was concomitantly decreased by 10%. This was accompanied by a 50% increase in plasma triglyceride concentrations and 15% decrease in HDL cholesterol concentrations. Only 3/16 (19%) non-obese participants had a pattern B LDL cholesterol profile (peak density of >1.033 g/ml), whilst 28/48 (58%) obese participants were pattern B. When expressed as a fraction of the LDL concentration, total sdLDL (i.e. LDL III + IV) showed highly significant correlations to plasma triglyceride concentrations and the triglyceride/HDL cholesterol ratio. Conclusions The prevalence of sdLDL is increased in obesity in a Thai population such that they demonstrate a similar atherogenic triad to that previously observed in European and American populations
Cyclic cycle systems of the complete multipartite graph
In this paper, we study the existence problem for cyclic -cycle
decompositions of the graph , the complete multipartite graph with
parts of size , and give necessary and sufficient conditions for their
existence in the case that
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