Electrically heated diaphragm eliminates use of pyrotechnics

Membrane-type diaphragm is used in systems where fluids are contained under pressure until a certain pressure threshold or point of time has been reached when the fluids are automatically released. The diaphragm is resistance heated until its strength is degraded to the point of rupture, thus releasing the contained fluids

The ionization mechanism of NGC 185: how to fake a Seyfert galaxy?

NGC 185 is a dwarf spheroidal satellite of the Andromeda galaxy. From mid-1990s onwards it was revealed that dwarf spheroidals often display a varied and in some cases complex star formation history. In an optical survey of bright nearby galaxies, NGC 185 was classified as a Seyfert galaxy based on its emission line ratios. However, although the emission lines in this object formally place it in the category of Seyferts, it is probable that this galaxy does not contain a genuine active nucleus. NGC 185 was not detected in radio surveys either in 6 or 20 cm, or X-ray observations, which means that the Seyfert-like line ratios may be produced by stellar processes. In this work, we try to identify the possible ionization mechanisms for this galaxy. We discussed the possibility of the line emissions being produced by planetary nebulae (PNe), using deep spectroscopy observations obtained with GMOS-N, at Gemini. Although the fluxes of the PNe are high enough to explain the integrated spectrum, the line ratios are very far from the values for the Seyfert classification. We then proposed that a mixture of supernova remnants and PNe could be the source of the ionization, and we show that a composition of these two objects do mimic Seyfert-like line ratios. We used chemical evolution models to predict the supernova rates and to support the idea that these supernova remnants should be present in the galaxy.Comment: 9 pages, 7 figures, accepted for publication in MNRA

Bacteria Use Type IV Pili to Walk Upright and Detach from Surfaces

1. Department of Bioengineering, California Nano Systems Institute,University of California, Los Angeles, CA 90024, USA. 2. Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX 77204, USA. 3. Department of Materials Science and Engineering, University of Illinois, Urbana-Champaign, IL 61801, USA. 4. Department of Civil Engineering and Geological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA.Bacterial biofilms are structured multicellular communities involved in a broad range of infections. Knowing how free-swimming bacteria adapt their motility mechanisms near surfaces is crucial for understanding the transition between planktonic and biofilm phenotypes. By translating microscopy movies into searchable databases of bacterial behavior, we identified fundamental type IV pili–driven mechanisms for Pseudomonas aeruginosa surface motility involved in distinct foraging strategies. Bacteria stood upright and “walked” with trajectories optimized for two-dimensional surface exploration. Vertical orientation facilitated surface detachment and could influence biofilm morphology.Center for Nonlinear Dynamic

Effect of Age on the Structure of Meissner Corpuscles in Forepad Digital Pads of Mice

Meissner corpuscles in forepaw digital pads of albino mice were examined by light and electron microscopy to determine structural age-changes. After 1.5 months of age, no intraepidermal nerve fibers were seen extending from corpuscles. From young (1.5-6 months) to middle age (9-15 months), corpuscles became larger and more complex, gaining more horizontally arranged terminals, associated lamellae and connective tissue. At old age (18-26 months), corpuscles became small and lobulated, appearing disorganized. There was no loosening of the corpuscle-epidermal interface. An increase in collagenous connective tissue and basal lamina duplication occurred with advancing age. Ultrastructural age-changes consisted of disorganization of the axonal organelles, rounding of the axon profiles with loss of axonal processes, regression of the perineural capsular epithelium, attenuation and loss of lamellae, loss of caveoli, mitochondrial degeneration and lipofuscin accumulation. Intraepidermal terminals were thought to be present only during the period of corpuscle development which extends only to include age 1.5 months. Corpuscle growth and maturation until middle age possibly indicated sensitivity compensation for loss of corpuscles and innervating axons. At old age, the disruption of corpuscle structure, especially with loss of axonal processes and horizontal arrangement of terminals, likely dampened the sensitivity of Meissner corpuscles, and raised their threshold to stimuli, perhaps making them nonfunctional. An increase in collagenous connective tissue was thought to have a significant effect on the physical transmission of pressure waves to the transducer. The significance of mitochondrial degeneration and lipofuscin accumulation was considered. Atrophic corpuscles seen in abundance by old age probably occurred as a consequence of age-changes in axonal transport promoting distal axonopathy

Age-changes of the Neuronal Component of Meissner Corpuscles in the Mouse Digital Pad

Silver impregnated sections of mouse digital pads were studied using light microscopy to detect age-related changes of the neuronal component of Meissner corpuscles. Direct microscopic observation, photomicrographs and camera lucida tracing were utilized. From qualitative observation, the corpuscular neurites were found to undergo morphological age-related changes of diameter, tortuosity, varicosity, branching and terminal expansion size. Quantitative examination was made of the number of corpuscles, corpuscular neurites, branching neurites, cross-innervations, terminal neurite expansions, neurite intraepidermal continuations and terminal axonal processes. The number of corpuscles and neurite intraepidermal continuations decreased with age while having significant linear correlation; whereas, branching increased with age while having significant linear correlation. Using camera lucida tracings, measurements were made with a Lenz Videoplan computer to determine changes of length and area of the neurites. Significant linear correlation for an age-change of length was not shown, but an increase with age until 12 months was indicated. However, area showed linear correlation, increasing with advancing age. Physiological correlates of the morphological findings were discussed

Heterodimensional FET with split drain

A modification to heterodimensional field effect transistors (HDFET) is introduced and demonstrated to provide novel switching capabilities. The modification consists of introducing a split drain into the HDFET structure allowing the transistor to operate as a single pole-double throw switch. By extension, multiple pole-multiple throw switches can be made within a single transistor structure by introduction of multiple split drains or sources. If the device is fabricated on silicon germanium substrates, compatibility of the structure with conventional CMOS processing is achievable, allowing for new applications in digital, mixed signal, and high voltage switching

Evidence for Extremely High Dust Polarization Efficiency in NGC 3184

Recent studies have found the Type II-plateau supernova (SN) 1999gi to be highly polarized (p_max = 5.8%, where p_max is the highest degree of polarization measured in the optical bandpass; Leonard & Filippenko 2001) and minimally reddened (E[B-V] = 0.21 +/- 0.09 mag; Leonard et al. 2002). From multiple lines of evidence, including the convincing fit of a ``Serkowski'' interstellar polarization (ISP) curve to the continuum polarization shape, we conclude that the bulk of the observed polarization is likely due to dust along the line of sight (l-o-s), and is not intrinsic to SN 1999gi. We present new spectropolarimetric observations of four distant Galactic stars close to the l-o-s to SN 1999gi (two are within 0.02 degrees), and find that all are null to within 0.2%, effectively eliminating Galactic dust as the cause of the high polarization. The high ISP coupled with the low reddening implies an extraordinarily high polarization efficiency for the dust along this l-o-s in NGC 3184: ISP / E(B-V) = 31^{+22}_{-9} % mag^{-1}. This is inconsistent with the empirical Galactic limit (ISP / E[B-V] < 9% mag^{-1}), and represents the highest polarization efficiency yet confirmed for a single sight line in either the Milky Way or an external galaxy.Comment: 27 pages, accepted for publication by the Astronomical Journa

Evaluation of the Impact of Texas Lignite Development on Texas Water Resources

Fuel shortages and resultant rising fuel costs as well as federal policies prompting energy independence have served to encourage power companies to exploit available lignite deposits of the western states as a viable fuel source. Large reserves of lignite found in a northeasterly trending belt through Texas have been only partially tapped. To develop this natural resource, large volumes of water will be required for mining, handling, processing, cooling, power generation, and land reclamation. Throughout the Texas lignite belt, physical characteristics vary widely depending mainly upon the amount of water present in any form. Research into the potential impact of the development of the Texas lignite resources on both the surface and groundwater resources of Texas has produced three separate areas within the lignite belt which have varying capabilities of supporting lignite development. The northeastern section of the lignite belt has sufficient surface water resources and backup groundwater resources to allow extensive development of lignite. The central section will support mining and development, but care must be taken to conserve and regulate water use. The southwestern section of the lignite belt does not possess sufficient ground or surface water resources for much, if any, lignite development. The most water thrifty methods of production would have to be employed for even limited development

Impact of Water Resource Development on Coastal Erosion, Brazos River, Texas

Major dam and reservoir development within the Brazos River Basin is correlative with a significant decrease in the suspended sediment load of the river and with increased coastal erosion rates near the delta. A hydrologic analysis of the river discharge, by use of cumulative frequency curves, shows that discharge control by dam regulation has reduced the frequency of high discharges, thus smoothing out the river hydrograph and reducing the amount of sediment the river is able to carry and deliver to the coastal zone. In addition, the reservoirs are presently trapping about 76¡% of all sand produced within the basin. An analysis of bed load samples taken downstream of the dams indicates that the sand sizes necessary for beach nourishment are not being transported through the lower reaches of the river. The amount of sand denied access to the coastal zone through the loss of the river's transporting ability and reservoir entrapment has been determined, and is shown to be enough to account for the entire increase in the coastal erosion rates in the study area since at least 1937. Future sand losses brought about by the construction of new reservoirs downstream of those presently on the Brazos River, or one of its major tributaries, can be predicted by the decrease in the effective drainage basin area