17,095 research outputs found
An Investigation of the Phenomenon of Separation in the Air Flow Around Simple Quadric Cylinders
The tests, conducted at the Guggenheim Aeronautical Laboratory of Stanford University, to investigate the phenomenon of separation in the air flow past geometric shapes are described in this report
A Proton Magnetic Resonance Study of the Association of Lysozyme with Monosaccharide Inhibitors
It has been shown that the acetamido methyl protons of N-acetyl-d-glucosamine undergo a chemical shift to higher fields in their proton magnetic resonance spectrum when the inhibitor is bound to lysozyme. The observed chemical shift in the presence of the enzyme is different for the agr- and ß-anomeric forms of 2-acetamido-2-deoxy-d-glucopyranose indicating either a difference in the affinity of the anomeric forms for lysozyme or different magnetic environments for the methyl protons in their enzyme-bound state. That the agr- and ß-anomeric forms of GlcAc bind to lysozyme in a competitive fashion was indicated by observing the proton magnetic resonance spectra in the presence of 2-acetamido-d3-2-deoxy-agr-d-glucopyranose. The methyl glycosides, methyl-agr-GlcAc and methyl-ß-GlcAc, were also shown to bind competitively with both anomers of GlcAc. Quantitative analysis of the chemical shift data observed for the association of GlcAc with lysozyme was complicated by the mutarotation of GlcAc between its agr- and ß-anomeric forms. However, in the case of the methyl glucosides, where the conformation of each anomer is frozen, it was possible to analyze the chemical shift data in a straightforward manner, and the dissociation constant as well as the chemical shift of the acetamido methyl protons of the enzyme-inhibitor complex was determined for both anomers. The results indicate that the two anomers of methyl-GlcAc bind to lysozyme with slightly different affinities but that the acetamido methyl groups of both anomers experience identical magnetic environments in the enzyme-inhibitor complex
Quantitative measurements of the thermopower of Andreev interferometers
Using a new second derivative technique and thermometers which enable us to
determine the local electron temperature in a mesoscopic metallic sample, we
have obtained quantitative measurements of the low temperature field and
temperature dependent thermopower of Andreev interferometers. As in previous
experiments, the thermopower is found to oscillate as a function of magnetic
field. The temperature dependence of the thermopower is nonmonotonic, with a
minimum at a temperature of K. These results are discussed from the
perspective of Andreev reflection at the normal-metal/superconductor interface.Comment: 6 pages, 4 figure
Evidence from satellite altimetry for small-scale convection in the mantle
Small scale convection can be defined as that part of the mantle circulation in which upwellings and downwellings can occur beneath the lithosphere within the interiors of plates, in contrast to the large scale flow associated with plate motions where upwellings and downwellings occur at ridges and trenches. The two scales of convection will interact so that the form of the small scale convection will depend on how it arises within the large scale flow. Observations based on GEOS-3 and SEASAT altimetry suggest that small scale convection occurs in at least two different ways
Intention and motor representation in purposive action
Are there distinct roles for intention and motor representation in explaining the purposiveness of action? Standard accounts of action assign a role to intention but are silent on motor representation. The temptation is to suppose that nothing need be said here because motor representation is either only an enabling condition for purposive action or else merely a variety of intention. This paper provides reasons for resisting that temptation. Some motor representations, like intentions, coordinate actions in virtue of representing outcomes; but, unlike intentions, motor representations cannot feature as premises or conclusions in practical reasoning. This implies that motor representation has a distinctive role in explaining the purposiveness of action. It also gives rise to a problem: were the roles of intention and motor representation entirely independent, this would impair effective action. It is therefore necessary to explain how intentions interlock with motor representations. The solution, we argue, is to recognise that the contents of intentions can be partially determined by the contents of motor representations. Understanding this content-determining relation enables better understanding how intentions relate to actions
Dreaming big? Self-valuations, aspirations, networks and the private-school earnings premium
An important axis of inequality in Britain is the private/state school divide. The success of private schools in Britain in delivering high academic achievements and better-paid jobs has been attributed to these schools engendering high self-evaluations, greater aspirations and social networks. Using recently repaired data on secondary school type from the 1970 British Cohort Study, we find that internal locus of control, aspirations and access to networks, but not self-esteem, are raised by private schooling. Locus of control and aspirations (but not networks or self-esteem) each have modest effects on earnings at age 42. Yet only a small part of the private school earnings premium is accounted for by all these factors. Much of the premium is due, rather, to educational attainments. This evidence suggests that strategies to strengthen self-evaluations or aspirations in state schools will contribute little on their own to the objective of greater equality or social mobility
A traveling wave decelerator for neutral polar molecules
Recently, a decelerator for neutral polar molecules has been presented that
operates on the basis of macroscopic, three-dimensional, traveling
electrostatic traps (Osterwalder et al., Phys. Rev. A 81, 051401 (2010)). In
the present paper, a complete description of this decelerator is given, with
emphasis on the electronics and the mechanical design. Experimental results
showing the transverse velocity distributions of guided molecules are shown and
compared to trajectory simulations. An assessment of non-adiabatic losses is
made by comparing the deceleration signals from 13-CO with those from 12-CO and
with simulated signals.Comment: 10 pages, 7 figure
Comment on the calculation of the pdf of the output of a two-branch switch and stay diversity system
Electron-hole imbalance in superconductor-normal metal mesoscopic structures
We analysed the electron-hole or, in another words, branch imbalance (BI) and
the related electric potential which may arise in a mesoscopic
superconductor/normal metal (S/N) structure under non-equilibrium conditions in
the presence of a supercurrent. Non-equilibrium conditions can be created in
different ways: a) a quasiparticle current flowing between the N reservoirs; b)
a temperature gradient between the N reservoirs and no quasiparticle current.
It is shown that the voltage oscillates with the phase difference
. In a cross-geometry structure the voltage arises in the
vertical branch and affects the conditions for a transition into the
-state.Comment: 6 pages, 5 figures, accepted for publication in Europhysics Letter
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