Voyager cartography

The Jovian and Saturnian satellites are being mapped at several scales from Voyager 1 and 2 data. The maps are especially formatted color mosaics, controlled photomosaics, and airbrush maps. At 1:5,000,000 scale, mapping of Io, Europa, and Ganymede is complete. At 1:15,000,000 scale, mapping of Io and Europa is complete, and mapping of Ganymede is approximately complete. A controlled mosaic of Rhea has been compiled as a Digital Image Model (DIM) in the same format as is being used for Mars. The mosaic is being formatted for publication as a two-sheet set (Lambert Azimuthal Equal Area, Mercator, and Polar Stereographic projections). Magnetic tape copies of the DIM have been distributed to regional Planetary Image Facilities and other interested users. The DIM has a scale of 1/16 degree/pixel, corresponding to approximately 833 m/pixel on Rhea. Details of the status of the various map series are reported quarterly to Planetary Geology Principal Investigators

Adventitious bud formation in leaf explants of some grapevine rootstock and scion cultivars

Die Bildung von Adventivknospen an Blattexplantaten einiger Unterlags- und Edelreissorten der RebeAdventivknospen bildeten sich am häufigsten an Blattexplantaten der Sorten Rupestris St. George, Thompson Seedless und Niagara (ca. 35-50 %), in mittlerer Häufigkeit bei Ramsey, Cabernet Sauvignon, Chardonnay und Concord (ca. 25-30 %), am wenigsten häufig bei 110-R und ARG 1 (20 % ). Explantate von Blattstielen waren im allgemeinen regenerationsfähiger als solche aus Blattspreiten. Die Art und Weise, in der die Mutterpflanzen kultiviert wurden (Klimakammer oder in vitro), wirkte sich später nicht auf die Bildung von Adventivknospen aus. Benzyladenin (10 μM) und a-Naphthylessigsiäure (0,05-0,10 μM) waren in Verbindung mit Cytokinin und Auxin für die Bildung von Adventivknospen am wirksamsten. An Blattspreiten-Explantaten wurden mehr Knospen gebildet (1-12) als an Blattstiel-Explantaten (1-6). Ein gleichbleibender Einfluß der Behandlung auf die Anzahl der Knospen je Explantat lag jedoch nicht vor. Der maßgebliche Faktor war der Prozentsatz der Explantate, die überhaupt Adventivknospen ausbildeten.

Radiometric performance of AVIRIS: Assessment for an arid region geologic target

Data from several AVIRIS flight lines were examined to assess instrument stability and response. Both scene and in-flight calibration data were analyzed statistically. The data clearly indicates that, although the instrument output was noisy and unstable at the time of the data acquisition, valuable spectral signatures can still be extracted and analyzed. Some first order calibration corrections can be performed by forcing internal consistency within the data. AVIRIS data are delivered in band-interleaved-by-line format, but high efficiency routines were developed which access the data as either image or spectral planes and enable effective statistical and visual examination of both AVIRIS scenes and ancillary files. Two methods were used to extract spectral information from segment 4 of the Kelso Dunes flight. Both successfully identified at least three distinct spectral signatures, but neither has positively identified a specific material

Elastin-Mediated Choroidal Endothelial Cell Migration: Possible Role in Age-Related Macular Degeneration

PURPOSE. Endothelial cell (EC) migration is a key event in angiogenesis, and is likely to play an important role in choroidal neovascularization in age-related macular degeneration (AMD). Altered elastin metabolism has been described in AMD, and the present study sought to determine the effects of elastin-derived peptides (EDPs) on choroidal EC migration and proliferation. METHODS. Migration of the chorioretinal EC line Rf/6a and a primary culture of human choroidal ECs through polycarbonate membrane inserts was quantified in the presence of elastin bioactive hexapeptides (BPs), EDPs, bovine serum albumin (BSA), or balanced salt solution. Proliferation assays and in vitro wound closure experiments were also performed in the presence of elastin fragments or balanced salt solution (control). Elastin overlay experiments were performed on sections of human eyes. RESULTS. For both Rf/6a and human primary choroidal ECs exposed to EDPs or BPs, the number of ECs that migrated through the polycarbonate membrane was significantly higher than ECs exposed to balanced salt solution alone or to BSA (P Ͻ 0.05) in all experiments. In contrast, the rate of EC proliferation did not significantly change in comparison to controls. Elastin binding sites were identified on choroidal ECs in human eyes. CONCLUSIONS. Elastin fragments increase choroidal EC migration, whereas they do not appear to increase or decrease EC proliferation. Local or systemic abnormalities in elastin physiology may participate in pathologic neovascular membrane formation in AMD. (Invest Ophthalmol Vis Sci. 2008;49: 5574 -5580) DOI:10.1167/iovs. A ge-related macular degeneration (AMD) is a major cause of blindness. The neovascular (wet) form of AMD is characterized by the abnormal growth of choroidal blood vessels into the sub-retinal space of the macula. This multistep process is likely to be initiated by the breakdown of Bruch's membrane which, when intact, prevents pathologic angiogenesis. In this process, choroidal ECs may migrate from the choroid into the sub-RPE and/or sub-retinal space. These ECs proliferate and form tubes (tubulogenesis), ultimately reorganizing their junctions to increase permeability across the newly formed vascular wall. The neovascular process in AMD can result in serous detachment of the retinal pigmented epithelium (RPE) and/or neurosensory retinal detachment, as well as fibrous disciform scarring beneath the retina, causing a catastrophic decrease in visual acuity. 1-5 Current treatments for neovascular AMD are focused primarily on vascular endothelial growth factor (VEGF)-mediated processes. 6 While VEGF is a potent inducer of angiogenesis, understanding the role of additional angiogenic stimuli would be invaluable for the development of improved treatments. 7 Elastin is a glycoprotein consisting of cross-linked 72 kDa tropoelastin subunits and is an abundant component of the extracellular matrix (ECM) of arteries, lung, and skin. 8 Breakdown of elastin results in the formation of elastin-derived peptides (EDPs), cross-linked fragments of tropoelastin of varying sizes. 10 Currently, it is unknown how these peptides are able to activate ECs and whether they are capable of activating ECs from other tissues, such as the choroid. It is plausible that EDPs bind to elastin binding proteins on the cell surface, inducing angiogenic behaviors such as cell migration and/or proliferation. Several lines of evidence suggest abnormal elastin metabolism occurs in Bruch's membrane in AMD. First, early onset choroidal neovascularization has been shown in patients with pseudoxanthoma elasticum. These patients may be at risk for developing choroidal neovascular membranes because of abnormalities in the elastic layer of Bruch's membrane, including breaks, clinically defined as angioid streaks. 11,12 Second, fibulin-5 missense mutations have been identified in association with AMD. 13 This mutation may contribute to AMD development by affecting the elastic layer of Bruch's membrane, since fibulin-5 participates in elastogenesis There is also evidence for abnormal systemic elastin metabolism in AMD. Blumenkranz et al. 11 found a correlation between choroidal neovascularization (CNV) and elastotic degeneration. Patients with exudative AMD demonstrated a greater than twofold increase in their susceptibility to elastotic degeneration of relatively sun-protected areas of the skin in dermal biopsies, suggesting that AMD is associated with systemic elastin abnormalities. 11 Serum levels of EDPs in patients with exudative AMD have also been found to be significantly higher than levels in non-exudative AMD patients and control patients

Low temperature shape relaxation of 2-d islands by edge diffusion

We present a precise microscopic description of the limiting step for low temperature shape relaxation of two dimensional islands in which activated diffusion of particles along the boundary is the only mechanism of transport allowed. In particular, we are able to explain why the system is driven irreversibly towards equilibrium. Based on this description, we present a scheme for calculating the duration of the limiting step at each stage of the relaxation process. Finally, we calculate numerically the total relaxation time as predicted by our results and compare it with simulations of the relaxation process.Comment: 11 pages, 5 figures, to appear in Phys. Rev.

Profile scaling in decay of nanostructures

The flattening of a crystal cone below its roughening transition is studied by means of a step flow model. Numerical and analytical analyses show that the height profile, h(r,t), obeys the scaling scenario dh/dr = F(r t^{-1/4}). The scaling function is flat at radii r<R(t) \sim t^{1/4}. We find a one parameter family of solutions for the scaling function, and propose a selection criterion for the unique solution the system reaches.Comment: 4 pages, RevTex, 3 eps figure

Symmetry based determination of space-time functions in nonequilibrium growth processes

We study the space-time correlation and response functions in nonequilibrium growth processes described by linear stochastic Langevin equations. Exploiting exclusively the existence of space and time dependent symmetries of the noiseless part of these equations, we derive expressions for the universal scaling functions of two-time quantities which are found to agree with the exact expressions obtained from the stochastic equations of motion. The usefulness of the space-time functions is illustrated through the investigation of two atomistic growth models, the Family model and the restricted Family model, which are shown to belong to a unique universality class in 1+1 and in 2+1 space dimensions. This corrects earlier studies which claimed that in 2+1 dimensions the two models belong to different universality classes.Comment: 18 pages, three figures included, submitted to Phys. Rev.

Nanoscale Equilibrium Crystal Shapes

The finite size and interface effects on equilibrium crystal shape (ECS) have been investigated for the case of a surface free energy density including step stiffness and inverse-square step-step interactions. Explicitly including the curvature of a crystallite leads to an extra boundary condition in the solution of the crystal shape, yielding a family of crystal shapes, governed by a shape parameter c. The total crystallite free energy, including interface energy, is minimized for c=0, yielding in all cases the traditional PT shape (z x3/2). Solutions of the crystal shape for c&#8800;0 are presented and discussed in the context of meta-stable states due to the energy barrier for nucleation. Explicit scaled relationships for the ECS and meta-stable states in terms of the measurable step parameters and the interfacial energy are presented.Comment: 35 page