Jet aircraft configuration Patent

Upper surface, external flow, jet-augmented flap configuration for high wing jet aircraft for noise reductio

Fcgamma receptor-mediated phagocytosis in macrophages lacking the Src family tyrosine kinases Hck, Fgr, and Lyn.

Macrophage Fcgamma receptors (FcgammaRs) mediate the uptake and destruction of antibody-coated viruses, bacteria, and parasites. We examined FcgammaR signaling and phagocytic function in bone marrow-derived macrophages from mutant mice lacking the major Src family kinases expressed in these cells, Hck, Fgr, and Lyn. Many FcgammaR-induced functional responses and signaling events were diminished or delayed in these macrophages, including immunoglobulin (Ig)G-coated erythrocyte phagocytosis, respiratory burst, actin cup formation, and activation of Syk, phosphatidylinositol 3-kinase, and extracellular signal-regulated kinases 1 and 2. Significant reduction of IgG-dependent phagocytosis was not seen in hck(-)(/)-fgr(-)(/)- or lyn(-)(/)- cells, although the single mutant lyn(-)(/)- macrophages did manifest signaling defects. Thus, Src family kinases clearly have roles in two events leading to FcgammaR-mediated phagocytosis, one involving initiation of actin polymerization and the second involving activation of Syk and subsequent internalization. Since FcgammaR-mediated phagocytosis did occur at modest levels in a delayed fashion in triple mutant macrophages, these Src family kinases are not absolutely required for uptake of IgG-opsonized particles

Wind-Tunnel Development of Ailerons for the Curtiss XP-60 Airplanem Special Report

An investigation was made in the LWAL 7- by 10-foot tunnel of internally balanced, sealed ailerons for the Curtiss XP-60 airplane. Ailerons with tabs and. with various amounts of balance were tested. Stick forces were estimated for several aileron arrangements including an arrangement recommended for the airplane. Flight tests of the recommended arrangement are discussed briefly in an appendix, The results of the wind-tunnel and flight tests indicate that the ailerons of large or fast airplanes may be satisfactorily balanced by the method developed

Chiral molecules split light: Reflection and refraction in a chiral liquid

A light beam changes direction as it enters a liquid at an angle from another medium, such as air. Should the liquid contain molecules that lack mirror symmetry, then it has been predicted by Fresnel that the light beam will not only change direction, but will actually split into two separate beams with a small difference in the respective angles of refraction. Here we report the observation of this phenomenon. We also demonstrate that the angle of reflection does not equal the angle of incidence in a chiral medium. Unlike conventional optical rotation, which depends on the path-length through the sample, the reported reflection and refraction phenomena arise within a few wavelengths at the interface and thereby suggest a new approach to polarimetry that can be used in microfluidic volumes

Thermal modelling of Advanced LIGO test masses

High-reflectivity fused silica mirrors are at the epicentre of current advanced gravitational wave detectors. In these detectors, the mirrors interact with high power laser beams. As a result of finite absorption in the high reflectivity coatings the mirrors suffer from a variety of thermal effects that impact on the detectors performance. We propose a model of the Advanced LIGO mirrors that introduces an empirical term to account for the radiative heat transfer between the mirror and its surroundings. The mechanical mode frequency is used as a probe for the overall temperature of the mirror. The thermal transient after power build-up in the optical cavities is used to refine and test the model. The model provides a coating absorption estimate of 1.5 to 2.0 ppm and estimates that 0.3 to 1.3 ppm of the circulating light is scattered on to the ring heater.Comment: 14 pages, 9 figure

Further Characterization of Dopamine Release by Permeabilized PC 12 Cells

Rat pheochromocytoma cells (PC 12) permeabilized with staphylococcal α-toxin release [3H]dopamine after addition of micromolar Ca2+. This does not require additional Mg2+-ATP (in contrast to bovine adrenal medullary chromaffin cells). We also observed Ca2+-dependent [3H]-dopamine release from digitonin-permeabilized PC 12 cells. Permeabilization with α-toxin or digitonin and stimulation of the cells were done consecutively to wash out endogenous Mg2+-ATP. During permeabilization, ATP was removed effectively from the cytoplasm by both agents but the cells released [3H]dopamine in response to micromolar Ca2+ alone. Replacement by chloride of glutamate, which could sustain mitochondrial ATP production in permeabilized cells, does not significantly alter catecholamine release induced by Ca2+. However, Mg2+ without ATP augments the Ca2+-induced release. The release was unaltered by thiol-, hydroxyl-, or calmodulin-interfering substances. Thus Mg2+-ATP, calmodulin, or proteins containing -SH or -OH groups are not necessary for exocytosis in permeabilized PC 12 cells

Bowhead Whale (Balaena mysticetus) Feeding near Point Barrow, Alaska, During the 1985 Spring Migration

Examination of stomach contents and behavioral observations showed conclusively that bowhead whales were feeding in the Point Barrow area during the spring of 1985. All three bowheads harvested near the village of Barrow had over five litres of pelagic zooplankton (calanoid copepods and euphausiids) in their stomachs. Over 60 whales were observed during the period 26 May through 6 June diving repeatedly under the landfast ice and feeding in an area 11.2 km southwest of Point Barrow. Observers recorded times for dive, surfacing and respiration intervals for these whales. The recorded times were significantly different from those of bowhead whales migrating past Point Barrow in the spring and from bowheads, whose major activity was feeding, recorded in the Canadian Beaufort Sea during the summer and fall.Key words: Balaena mysticetus, Point Barrow, feeding, bowhead whale, behavior, copepod,  euphausiid, respiration, springUn examen du contenu stomacal de baleines franches et des observations de leur comportement ont montré sans aucun doute qu’elles se nourrissaient dans la zone de Point Barrow pendant le printemps de1985. Les trois baleines franches pêchées près du village de Barrow avaient toutes dans l’estomac plus de cinq litres de zooplancton pélagique (copépodes calanoïdes et euphausiacés). Pendant la période allant du 26 mai au 6 juin, on a observé plus de 60 baleines qui plongeaient de façon répétée sous la banquise côtière pour se nourrir dans une zone située à 11,2 km au sud-ouest de Point Barrow. Les observateurs ont noté le moment de la plongée et celui du retour à la surface, et l’intervalle entre les souffles des baleines. Les durées enregistrées étaient nettement différentes de celles mesurées pour des baleines franches qui passaient à Point Barrow pendant leur migration au printemps, et de celles enregistrées dans la mer de Beaufort canadienne en été et en automne pour des baleines franches dont l’activité principale était de se nourrir.Mots clés: Balaena mysticetus, Point Barrow, se nourrir, baleine franche, comportement, copépode, euphausiacé, respiration, printemp

Spitzer observations of the asteroid-comet transition object and potential spacecraft target 107P (4015) Wilson-Harrington

Context. Near-Earth asteroid-comet transition object 107P/ (4015) Wilson-Harrington is a possible target of the joint European Space Agency (ESA) and Japanese Aerospace Exploration Agency (JAXA) Marco Polo sample return mission. Physical studies of this object are relevant to this mission, and also to understanding its asteroidal or cometary nature. Aims. Our aim is to obtain significant new constraints on the surface thermal properties of this object. Methods. We present mid-infrared photometry in two filters (16 and 22 microns) obtained with NASA's Spitzer Space Telescope on February 12, 2007, and results from the application of the Near Earth Asteroid Thermal Model (NEATM).We obtained high S/N in two mid-IR bands allowing accurate measurements of its thermal emission. Results. We obtain a well constrained beaming parameter (eta = 1.39 +/- 0.26) and obtain a diameter and geometric albedo of D = 3.46 +/- 0.32 km, and pV = 0.059 +/- 0.011. We also obtain similar results when we apply this best-fitting thermal model to single-band mid-IR photometry reported by Campins et al. (1995), Kraemer et al. (2005) and Reach et al. (2007). Conclusions. The albedo of 4015 Wilson-Harrington is low, consistent with those of comet nuclei and primitive C-, P-, D-type asteorids. We establish a rough lower limit for the thermal inertia of W-H of 60 Jm^-2s^(-0.5)K^-1 when it is at r=1AU, which is slightly over the limit of 30 Jm^-2s^(-0.5)K-1 derived by Groussin et al. (2009) for the thermal inertia of the nucleus of comet 22P/Kopff.Comment: 4 pages, 1 figure and 3 tables. Paper accepted for publicatio

A new approach to modelling impacts on rubble pile asteroid simulants

Many asteroids with low bulk densities must have a rubble pile structure and internal voids. Although little is known about their internal structure, numerical simulations of impact events on these asteroids rely on assumptions on how the voids are distributed. We present a new approach to model impacts on rubble pile asteroids that explicitly takes into account their internal structure. The formation of the asteroid is modelled as a rubble pile aggregate of spherical pebbles of different sizes. This aggregate is then converted into a high-resolution smoothed particle hydrodynamics (SPH) model, accounting for macroporosity inside the pebbles. We compare impact-event outcomes for a large set of internal configurations to explore the parameter space of our model-building process. The analysis of the fragment size distribution and the disruption threshold quantifies the specific influence of each input parameter. The size distribution of the pebbles used in our model is a simple power law, containing three free parameters: the slope α, the lower cut-off radius rmin and the upper cut-off radius rmax. The influence of all three parameters on the outcome is assessed in this paper. The existence of void space in our model increases the resistance against collisional disruption, a behaviour previously reported based on numerical simulations using a continuum description of porous material (Holsapple 2009). We show, for a set of asteroid collisions typical for small asteroids in the main belt, that no a priori knowledge of the exact size distribution of the pebbles inside the asteroid is needed, as the choice of the corresponding parameters does not directly correlate with the impact outcome