Charging of flexible solar array substrates in kilovolt electron beams

A series of survey tests were conducted to evaluate samples of flexible solar arrays. The samples used woven carbon fibers and/or coatings to increase the surface conductivity of the KAPTON substrate and thereby reduce surface charging. Four different samples were evaluated by exposing them to monoenergetic electron beams of 2 to 20 KeV at a current density of 1 nA sq cm. Simulated eclipse tests were also conducted. The results were as expected; the more continuous the conductive pattern, the lower the surface charging

Developing a site-conditions map for seismic hazard Assessment in Portugal

The evaluation of site effects on a broad scale is a critical issue for seismic hazard and risk assessment, land use planning and emergency planning. As characterization of site conditions based on the shear-wave velocity has become increasingly important, several methods have been proposed in the literature to estimate its average over the first thirty meters (Vs30) from more extensively available data. These methods include correlations with geologic-geographic defined units and topographic slope. In this paper we present the first steps towards the development of a site–conditions map for Portugal, based on a regional database of shear-wave velocity data, together with geological, geographic, and lithological information. We computed Vs30 for each database site and classified it according to the corresponding geological-lithological information using maps at the smallest scale available (usually 1:50000). We evaluated the consistency of Vs30 values within generalized-geological classes, and assessed the performance of expedient methodologies proposed in the literature

Testing of typical spacecraft materials in a simulated substorm environment

The test specimens were spacecraft paints, silvered Teflon, thermal blankets, and solar array segments. The samples, ranging in size from 300 to 1000 sq cm were exposed to monoenergetic electron energies from 2 to 20 keV at a current density of 1 NA/sq cm. The samples generally behaved as capacitors with strong voltage gradient at their edges. The charging characteristics of the silvered Teflon, Kapton, and solar cell covers were controlled by the secondary emission characteristics. Insulators that did not discharge were the spacecraft paints and the quartz fiber cloth thermal blanket sample. All other samples did experience discharges when the surface voltage reached -8 to -16kV. The discharges were photographed. The breakdown voltage for each sample was determined and the average energy lost in the discharge was computed

Earthquake Mitigation in the Lisbon and Lower Tagus Valley area, Portugal

The capital city of Lisbon and the Lower Tagus Valley region of central Portugal mainland are located in the Eurasian plate about 350 Km from the approximately E-W oriented Eurasia-Africa plate boundary. It is characterized by low slip-rates (<0.4 mm/year) and a moderate seismicity, occasionally shaken by some important historical earthquakes causing significant damages and economical losses. The most well know damaging earthquakes occurred in 1344, 1531, 1755, 1909 and 1969. The seismic hazard evaluation and mitigation of the area is therefore of great importance to this densely populated area. This paper focuses the evaluation of P- wave and S-wave seismic velocities of the shallowest surface using seismic refraction data interpretation and in- situ lithostratigraphic studies to obtain geotechnical parameters such as Vp/Vs ratios and the Poisson coefficient, estimated to provide information for future site effect studies and preliminary VS30 and soil classification maps. The information will also be used to correct earthquake records since this information was also collected close to the location of seismological stations. The soil classification is based upon the European Code 8 for civil engineering which was carried out for land use planning and design of critical facilities. Hundreds of available boreholes drilled for engineering (with SPT data) and water supply were used to confirm layer thicknesses and lithologies at depth together with a detailed geological survey of each profile area. It is the first time VS30 maps and a soil classification based on geophysical and geotechnical parameters is attempted for this highly populated region

Spectral Evidence for Widespread Galaxy Outflows at z>4

We present discovery spectra of a sample of eight lensed galaxies at high redshift, 3.7<z<5.2, selected by their red colors in the fields of four massive clusters: A1689, A2219, A2390, and AC114. Metal absorption lines are detected and observed to be blueshifted by 300-800 km/s with respect to the centroid of Ly-alpha emission. A correlation is found between this blueshift and the equivalent width of the metal lines, which we interpret as a broadening of saturated absorption lines caused by a dispersion in the outflow velocity of interstellar gas. Local starburst galaxies show similar behavior, associated with obvious gas outflows. We also find a trend of increasing equivalent width of Ly-alpha emission with redshift, which may be a genuine evolutionary effect towards younger stellar populations at high redshift with less developed stellar continua. No obvious emission is detected below the Lyman limit in any of our spectra, nor in deep U or B-band images. The UV continua are reproduced well by early B-stars, although some dust absorption would allow a fit to hotter stars. After correcting for the lensing, we derive small physical sizes for our objects, ~0.5-5 kpc/h for a flat cosmology with Omega_m=0.3, Omega_Lambda=0.7. The lensed images are only marginally resolved in good seeing despite their close proximity to the critical curve, where large arcs are visible and hence high magnifications of up to ~20x are inferred. Two objects show a clear spatial extension of the Ly-alpha emission relative to the continuum starlight, indicating a ``breakout'' of the gas. The sizes of our galaxies together with their large gas motion suggests that outflows of gas are common at high redshift and associated with galaxy formation.Comment: 48 pages, 16 figures, ApJ, in press. Manuscript with full resolution color images available at (http://astro.princeton.edu/~bfrye

Photometric redshifts from reconstructed QSO templates

From SDSS commissioning photometric and spectroscopic data, we investigate the utility of photometric redshift techniques to the task of estimating QSO redshifts. We consider empirical methods (e.g. nearest-neighbor searches and polynomial fitting), standard spectral template fitting and hybrid approaches (i.e. training spectral templates from spectroscopic and photometric observations of QSOs). We find that in all cases, due to the presence of strong emission-lines within the QSO spectra, the nearest-neighbor and template fitting methods are superior to the polynomial fitting approach. Applying a novel reconstruction technique, we can, from the SDSS multicolor photometry, reconstruct a statistical representation of the underlying SEDs of the SDSS QSOs. Although, the reconstructed templates are based on only broadband photometry the common emission lines present within the QSO spectra can be recovered in the resulting spectral energy distributions. The technique should be useful in searching for spectral differences among QSOs at a given redshift, in searching for spectral evolution of QSOs, in comparing photometric redshifts for objects beyond the SDSS spectroscopic sample with those in the well calibrated photometric redshifts for objects brighter than 20th magnitude and in searching for systematic and time variable effects in the SDSS broad band photometric and spectral photometric calibrations.Comment: 21 pages, 9 figures, LaTeX AASTeX, submitted to A

Stereoselective Synthesis of 1-Hydroxymethyl-4-phenylsulfonylbutadienes

Reactividad de sulfonas para la obtención de sistemas dienicos.[ES]Reactividad de sulfonas para la obtención de sistemas dienicos.CICYT, Junta Castilla y Leon (SA 44-96) y Ministerio de Educación y Cienci

Deep Imaging of AXJ2019+112: The Luminosity of a ``Dark Cluster''

We detect a distant cluster of galaxies centered on the QSO lens and luminous X-ray source AXJ2019+112, a.k.a. ``The Dark Cluster'' (Hattori et al 1997). Using deep V,I Keck images and wide-field K_s imaging from the NTT, a tight red sequence of galaxies is identified within a radius of 0.2 h^{-1} Mpc of the known z=1.01 elliptical lensing galaxy. The sequence, which includes the central elliptical galaxy, has a slope in good agreement with the model predictions of Kodama et al (1998) for z~1. We estimate the integrated rest-frame luminosity of the cluster to be L_V > 3.2 x 10^{11}h^{-2}L_{\sun} (after accounting for significant extinction at the low latitude of this field), more than an order of magnitude higher than previous estimates. The central region of the cluster is deconvolved using the technique of Magain, Courbin & Sohy (1998), revealing a thick central arc coincident with an extended radio source. All the observed lensing features are readily explained by differential magnification of a radio loud AGN by a shallow elliptical potential. The QSO must lie just outside the diamond caustic, producing two images, and the arc is a highly magnified image formed from a region close to the center of the host galaxy, projecting inside the caustic. The mass--to--light ratio within an aperture of 0.4 h ^{-1} Mpc is M_x/L_V= 224^{+112}_{-78}h(M/L_V)_{\sun}, using the X-ray temperature. The strong lens model yields a compatible value, M/L_V= 372^{+94}_{-94}h(M/L_V)_{\sun}, whereas an independent weak lensing analysis sets an upper limit of M/L_V <520 h(M/L_V)_{\sun}, typical of massive clusters.Comment: AAS Latex format, 24 pages, 9 figures. Fig 1a,b available at http://astro.berkeley.edu/~benitezn/cluster.html . Submitted to ApJ on August 15t

Sequential Colocalization of ERa, PR, and AR Hormone Receptors Using Confocal Microscopy Enables New Insights into Normal Breast and Prostate Tissue and Cancers

Multiplex immunohistochemistry (mIHC) use markers staining different cell populations applying widefield optical microscopy. Resolution is low not resolving subcellular co-localization. We sought to colocalize markers at subcellular level with antibodies validated for clinical diagnosis, including the single secondary antibody (combination of anti-rabbit/mouse-antibodies) used for diagnostic IHC with any primary antibody, and confocal microscopy. We explore colocalization in the nucleus (ColNu) of nuclear hormone receptors (ERa, PR, and AR) along with the baseline marker p63 in paired samples of breast and prostate tissues. We established ColNu mIHCF as a reliable technique easily implemented in a hospital setting. In ERa+ breast cancer, we identified different colocalization patterns (nuclear or cytoplasmatic) with PR and AR on the luminal epithelium. A triple-negative breast-cancer case expressed membrane-only ERa. A PR-only case was double positive PR/p63. In normal prostate, we identified an ERa+/p63+/AR-negative distinct population. All prostate cancer cases characteristically expressed ERa on the apical membrane of the AR+ epithelium. We confirmed this using ERa IHC and needle-core biopsies. ColNu mIHCF is feasible and already revealed a new marker for prostate cancer and identified sub-patterns in breast cancer. It could be useful for pathology as well as for functional studies in normal prostate and breast tissues