Composite transport wing technology development: Design development tests and advanced structural concepts

Numerous design concepts, materials, and manufacturing methods were investigated for the covers and spars of a transport box wing. Cover panels and spar segments were fabricated and tested to verify the structural integrity of design concepts and fabrication techniques. Compression tests on stiffened panels demonstrated the ability of graphite/epoxy wing upper cover designs to achieve a 35 percent weight savings compared to the aluminum baseline. The impact damage tolerance of the designs and materials used for these panels limits the allowable compression strain and therefore the maximum achievable weight savings. Bending and shear tests on various spar designs verified an average weight savings of 37 percent compared to the aluminum baseline. Impact damage to spar webs did not significantly degrade structural performance. Predictions of spar web shear instability correlated well with measured performance. The structural integrity of spars manufactured by filament winding equalled or exceeded those fabricated by hand lay-up. The information obtained will be applied to the design, fabrication, and test of a full-scale section of a wing box. When completed, the tests on the technology integration box beam will demonstrate the structural integrity of an advanced composite wing design which is 25 percent lighter than the metal baseline

Nonlinear complexity of the Naor-Reingold pseudo-random function

This is a preprint of a book chapter published in Lecture Notes in Computer Science,1787, Springer-Verlag, Berlin (2000). The original publication is available at www.springerlink.com.We obtain an exponential lower bound on the non-linear complexity of the new pseudo-random function, introduced recently by M. Naor and O. Reingold. This bound is an extension of the lower bound on the linear complexity of this function that has been obtained by F. Griffin and I. E. Shparlinski

Laurentian Provenance of Archean Mantle Fragments in the Proterozoic Baltic Crust of the Norwegian Caledonides

The Proterozoic gneisses of the Western Gneiss Region (WGR) of western Norway experienced HP-UHP metamorphism during the 435-390 Ma Caledonian (Scandian) orogeny, and locally enclose numerous large bodies of Archean peridotite. Competing models for the emplacement of these peridotites into the gneisses involve either (1) upthrusting of subcontinental mantle into overlying gneisses or (2) 'sinking emplacement' of peridotites from the Laurentian mantle wedge into the upper surface of the subducting Baltica plate. The first model implies the existence of Archean lower crust below the outcropping gneisses. To evaluate these models we have carried out a regional survey of the U-Pb age, Hf isotope composition and trace-element compositions of detrital zircon grains collected from drainages in the northern half of the WGR. The zircon data indicate that the gneisses that make up the crust of the WGR were originally generated during the 1·7-1·5 Ga Gothian orogeny. The Hf isotope signatures of these zircons indicate a juvenile (i.e. mantle) origin; there is no evidence, from either inherited zircons or the Hf isotope data, that Archean crustal materials were involved in the genesis of these gneisses. The Sveconorwegian orogeny (1·3 to < 1·0 Ga) that overprinted the Gothian gneisses involved both juvenile magmatic additions to the crust and remelting of the Gothian basement; these Sveconorwegian-age magmas also show no evidence of Archean contributions. A population of zircons collected from a drainage area containing large mantle-derived peridotite bodies includes anhedral to rounded grains with distinctive trace-element patterns consistent with derivation from depleted rocks; these are inferred to be derived from the peridotites and/or their enclosed eclogites and pyroxenites. These zircons give Archean Hf model ages, but 207Pb/206Pb ages ranging from Archean to Caledonian, suggesting that the younger ages reflect resetting during later thermal events. The Archean zircon ages are consistent with Archean Re-Os model ages previously obtained on the peridotites. In the absence of any evidence for Archean crust (and hence Archean mantle) beneath southern Baltica, we infer that the peridotite massifs represent fragments of the subcontinental lithosphere beneath Laurentia, and were introduced tectonically into the gneisses during the Caledonian subduction of Baltica beneath Laurentia

Reducing Particle Size Enhances Chemical Treatment in Finishing Diets

Three hundred-sixty calf-fed steers were fed either treated or untreated corn stover that was previously ground through a 1-in or 3–in screen. Treated stover diets improved ADG and F:G compared to untreated. Reducing particle size improved ADG and F:G but did not influence DMI. Compared to a control diet with 5% roughage and 15 percentage units more corn, diets with 20% treated corn stover had similar F:G, ADG, DMI, and carcass quality. Up to 15% additional corn can be replaced with treated corn stover when diets contain wet distillers grains, and may be further enhanced by reducing particle size before chemical treatment

Reducing Particle Size Enhances Chemical Treatment in Finishing Diets

Three hundred-sixty calf-fed steers were fed either treated or untreated corn stover that was previously ground through a 1-in or 3–in screen. Treated stover diets improved ADG and F:G compared to untreated. Reducing particle size improved ADG and F:G but did not influence DMI. Compared to a control diet with 5% roughage and 15 percentage units more corn, diets with 20% treated corn stover had similar F:G, ADG, DMI, and carcass quality. Up to 15% additional corn can be replaced with treated corn stover when diets contain wet distillers grains, and may be further enhanced by reducing particle size before chemical treatment

Suppression of human immunodeficiency virus replication during acute measles.

To determine the effect of measles virus coinfection on plasma human immunodeficiency virus (HIV) RNA levels, a prospective study of hospitalized children with measles was conducted between January 1998 and October 2000 in Lusaka, Zambia. Plasma HIV RNA levels were measured during acute measles and 1 month after hospital discharge. The median plasma HIV RNA level in 33 children with measles who were followed longitudinally was 5339 copies/mL at study entry, 60,121 copies/mL at hospital discharge, and 387,148 copies/mL at 1-month follow-up. The median plasma HIV RNA level in children without acute illness was 228,454 copies/mL. Plasma levels of immune activation markers were elevated during the period of reduced plasma HIV RNA. Plasma levels of several potential HIV suppressive factors also were elevated during acute measles. HIV replication is transiently suppressed during acute measles at a time of intense immune activation

Sulfated glycans engage the Ang–Tie pathway to regulate vascular development

The angiopoietin (Ang)–Tie pathway is essential for the proper maturation and remodeling of the vasculature. Despite its importance in disease, the mechanisms that control signal transduction through this pathway are poorly understood. Here, we demonstrate that heparan sulfate glycosaminoglycans (HS GAGs) regulate Ang–Tie signaling through direct interactions with both Ang ligands and Tie1 receptors. HS GAGs formed ternary complexes with Ang1 or Ang4 and Tie2 receptors, resulting in potentiation of endothelial survival signaling. In addition, HS GAGs served as ligands for the orphan receptor Tie1. The HS–Tie1 interaction promoted Tie1–Tie2 heterodimerization and enhanced Tie1 stability within the mature vasculature. Loss of HS–Tie1 binding using CRISPR–Cas9-mediated mutagenesis in vivo led to decreased Tie protein levels, pathway suppression and aberrant retinal vascularization. Together, these results reveal that sulfated glycans use dual mechanisms to regulate Ang–Tie signaling and are important for the development and maintenance of the vasculature