Improved photoetching fabrication method

Photoetching method producing well-defined lines with minimum undercutting was developed for etching coolant passages in nickel sheet. Phosphate coating is applied over conventional silver plate maskant and phosphoric acid solution is used to remove silver maskant. Phosphoric acid prevents etching of silver edges and mask has sharply-defined lines

The Fluctuating Pressure Field in a Supersonic Turbulent Boundary Layer

The fluctuating pressure field in a supersonic turbulent boundary laye

Hearing in three dimensions: Sound localization

The ability to localize a source of sound in space is a fundamental component of the three dimensional character of the sound of audio. For over a century scientists have been trying to understand the physical and psychological processes and physiological mechanisms that subserve sound localization. This research has shown that important information about sound source position is provided by interaural differences in time of arrival, interaural differences in intensity and direction-dependent filtering provided by the pinnae. Progress has been slow, primarily because experiments on localization are technically demanding. Control of stimulus parameters and quantification of the subjective experience are quite difficult problems. Recent advances, such as the ability to simulate a three dimensional sound field over headphones, seem to offer potential for rapid progress. Research using the new techniques has already produced new information. It now seems that interaural time differences are a much more salient and dominant localization cue than previously believed

Clostridium septicum aortitis with synchronous ascending colon and rectal adenocarcinoma.

Clostridium septicum (C. septicum) aortitis is a rare condition frequently associated with colon adenocarcinoma and carries a poor prognosis. We report the case of a 66-year-old man who presented with abdominal pain, blood in the stool, fever and chills. Laboratory tests were significant for leukocytosis and microcytic anemia. Abdominal imaging revealed a right colon mass and aortitis. Colonoscopy confirmed the right colon mass and also discovered a rectal mass, both adenocarcinomas. Treatment consisted of antibiotics, aortic repair, right hemi-colectomy and later trans-anal excision of the rectal mass. Blood cultures and the aortic specimen grew C. septicum. The patient improved and was doing well in follow up

Free surface flows with large slopes: beyond lubrication theory

The description of free surface flows can often be simplified to thin film (or lubrication) equations, when the slopes of the liquid-gas interface are small. Here we present a long wavelength theory that remains fully quantitative for steep interface slopes, by expanding about Stokes flow in a wedge. For small capillary numbers, the variations of the interface slope are slow and can be treated perturbatively. This geometry occurs naturally for flows with contact lines: we quantify the difference with ordinary lubrication theory through a numerical example and analytically recover the full Cox-Voinov asymptotic solution.Comment: 4 pages, 3 figure

Ultrastructural immunolocalization of histones (H2B, H3, H4), transition protein (TP1) and protamine in rabbit spermatids and spermatozoa nuclei. Relation to condensation of the chromatin

The histones H2B, H3 and H4, the transition protein TP1 and protamine were localised using ultrastructural immunocytochemistry in nuclei of rabbit spermatids and spermatozoa. Histones are present in round spermatid nuclei and are lost during the elongation of nuclei. TP1 and protamine appear simultaneously in all nuclei during this period. TP1 is located at the periphery of chromatin cords, while protamine seems to be located at random in the same cords. TP1 is lost in most elongated sprematids during step 13 of spermiogenesis, and the protamine stays in all sperm nuclei. TP1 remains persent in some old spermatids and ejaculated spermatozoa. In the rabbit, 3--6% of sperm nuclei decondense spontaneously. Most are characterized by a retention of TP1. Respective roles of TP1 and the protamine in spermatid nuclear condensation are discussed

Free-Stream Boundaries of Turbulent Flows

Report presents the results of an experimental and theoretical study made of the instantaneously sharp and irregular front which is always found to separate turbulent fluid from contiguous "nonturbulent" fluid at a free-stream boundary. This distinct demarcation is known to give an intermittent character to hot-wire signals in the boundary zone. The overall behavior of the front is described statistically in terms of its wrinkle-amplitude growth and its lateral propagation relative to the fluid as functions of downstream coordinate

Emerging evidence of plant domestication as a landscape-level process

The evidence from ancient crops over the past decade challenges some of our most basic assumptions about the process of domestication. The emergence of crops has been viewed as a technologically progressive process in which single or multiple localized populations adapt to human environments in response to cultivation. By contrast, new genetic and archaeological evidence reveals a slow process that involved large populations over wide areas with unexpectedly sustained cultural connections in deep time. We review evidence that calls for a new landscape framework of crop origins. Evolutionary processes operate across vast distances of landscape and time, and the origins of domesticates are complex. The domestication bottleneck is a redundant concept and the progressive nature of domestication is in doubt

A Survey About Nothing: Monitoring a Million Supergiants for Failed Supernovae

Extragalactic transient searches have historically been limited to looking for the appearance of new sources such as supernovae. It is now possible to carry out a new kind of survey that will do the opposite, that is, search for the disappearance of massive stars. This will entail the systematic observation of galaxies within a distance of 10 Mpc in order to watch ~10^6 supergiants. Reaching this critical number ensures that something will occur yearly, since these massive stars must end their lives with a core collapse within ~10^6 years. Using deep imaging and image subtraction it is possible to determine the fates of these stars whether they end with a bang (supernova) or a whimper (fall out of sight). Such a survey would place completely new limits on the total rate of all core collapses, which is critical for determining the validity of supernova models. It would also determine the properties of supernova progenitors, better characterize poorly understood optical transients, such as eta Carina-like mass ejections, find and characterize large numbers of Cepheids, luminous blue variables and eclipsing binaries, and allow the discovery of any new phenomena that inhabit this relatively unexplored parameter space.Comment: final version, 7 pages, 5 figures, ApJ in pres