Effects of Nacelle configuration/position on performance of subsonic transport

An experimental study was conducted to explore possible reductions in installed propulsion system drag due to underwing aft nacelle locations. Both circular (C) and D inlet cross section nacelles were tested. The primary objectives were: to determine the relative installed drag of the C and D nacelle installations; and, to compare the drag of each aft nacelle installation with that of a conventional underwing forward, drag of each aft nacelle installation with that of a conventional underwing forward, pylon mounted (UTW) nacelle installation. The tests were performed in the NASA-Langley Research Center 16-Foot Transonic Wind Tunnel at Mach numbers from 0.70 to 0.85, airplane angles of attack from -2.5 to 4.1 degrees, and Reynolds numbers per foot from 3.4 to 4.0 million. The nacelles were installed on the NASA USB full span transonic transport model with horizontal tail on. The D nacelle installation had the smallest drag of those tested. The UTW nacelle installation had the largest drag, at 6.8 percent larger than the D at Mach number 0.80 and lift coefficient (C sub L) 0.45. Each tested configuration still had some interference drag, however. The effect of the aft nacelles on airplane lift was to increase C sub L at a fixed angle of attack relative to the wing body. There was higher lift on the inboard wing sections because of higher pressures on the wing lower surface. The effects of the UTW installation on lift were opposite to those of the aft nacelles

Multiple junction biasing of superconducting tunnel junction detectors

We describe a new biasing scheme for single photon detectors based on superconducting tunnel junctions. It replaces a single detector junction with a circuit of three junctions and achieves biasing of a detector junction at subgap currents without the use of an external magnetic field. The biasing occurs through the nonlinear interaction of the three junctions, which we demonstrate through numerical simulation. This nonlinear state is numerically stable against external fluctuations and is compatible with high fidelity electrical readout of the photon-induced current. The elimination of the external magnetic field potentially increases the capability of these types of photon detectors and eases constraints involved in the fabrication of large detector arrays.Comment: 15 pages, including 3 figure

Thermal depinning of fluxons in ratchet discrete Josephson rings

We study numerically the thermal depinning of single fluxons in ratchet Josephson junction rings. Rings are made of 9 junctions with 3 different critical currents. We present results for a wide range of the main physical parameters of the system: damping, coupling and temperature. The computed results can be well understood in the framework of single particle thermal activation theories

Characterization of a Functional Comt1 Haplotype in Inbred Strains of Mice

We have pursued a genome-wide approach to examining strain-specific variations in gene expression in the brain of 29 inbred strains of mice. The highest association was found within the locus of the Catechol-O-Methyltransferase (Comt1) gene, coding for an ubiquitously expressed enzyme that maintains basic biologic functions by inactivating catecholamines. In human and mouse, COMT has been associated with multiple behavioral phenotypes, including pain sensitivity and stress response. Multiple brain regions in 29 inbred strains of mice were analyzed for Comt1 expression levels using a genome wide array. Differential expression levels, validated with qPCR, were observed for Comt1. A B2 Short Interspersed Nucleotide Element (SINE) was identified as an insertion in the 3'UTR of Comt1 in 14 strains of a shared haplotype. Experiments using mammalian expression vectors of full length cDNA clones with and without the SINE element present demonstrate the SINE haplotype (+SINE) to have greater Comt1 enzymatic activity. Within strains examined to date, +SINE mice have increased enzymatic function, decreased sensitivity for thermal and chemical- induced pain assays and behavioral differences in several anxiety assays. These results suggest that a haplotype, defined by a 3'UTR B2 SINE element, regulates Comt1 expression and mouse behavior

Band structure analysis of the conduction-band mass anisotropy in 6H and 4H SiC

The band structures of 6H and 4H SiC calculated by means of the FP-LMTO method are used to determine the effective mass tensors for their conduction-band minima. The results are shown to be consistent with recent optically detected cyclotron resonance measurements and predict an unusual band filling dependence for 6H-SiC.Comment: 5 pages including 4 postscript figures incorporated with epsfig figs. available as part 2: sicfig.uu self-extracting file to appear in Phys. Rev. B: Aug. 15 (Rapid Communications

Increased accuracy of ligand sensing by receptor internalization

Many types of cells can sense external ligand concentrations with cell-surface receptors at extremely high accuracy. Interestingly, ligand-bound receptors are often internalized, a process also known as receptor-mediated endocytosis. While internalization is involved in a vast number of important functions for the life of a cell, it was recently also suggested to increase the accuracy of sensing ligand as the overcounting of the same ligand molecules is reduced. Here we show, by extending simple ligand-receptor models to out-of-equilibrium thermodynamics, that internalization increases the accuracy with which cells can measure ligand concentrations in the external environment. Comparison with experimental rates of real receptors demonstrates that our model has indeed biological significance.Comment: 9 pages, 4 figures, accepted for publication in Physical Review

Egalitarian justice and expected value

According to all-luck egalitarianism, the differential distributive effects of both brute luck, which defines the outcome of risks which are not deliberately taken, and option luck, which defines the outcome of deliberate gambles, are unjust. Exactly how to correct the effects of option luck is, however, a complex issue. This article argues that (a) option luck should be neutralized not just by correcting luck among gamblers, but among the community as a whole, because it would be unfair for gamblers as a group to be disadvantaged relative to non-gamblers by bad option luck; (b) individuals should receive the warranted expected results of their gambles, except insofar as individuals blamelessly lacked the ability to ascertain which expectations were warranted; and (c) where societal resources are insufficient to deliver expected results to gamblers, gamblers should receive a lesser distributive share which is in proportion to the expected results. Where all-luck egalitarianism is understood in this way, it allows risk-takers to impose externalities on non-risk-takers, which seems counterintuitive. This may, however, be an advantage as it provides a luck egalitarian rationale for assisting ‘negligent victims’