3,837 research outputs found

    Potential role of remote sensing in disaster relief management

    Get PDF
    Baseline or predisaster data which would be useful to decision making in the immediate postdisaster period were suggested for the six areas of public health concern along with guidelines for organizing these data. Potential sources of these data are identified. In order to fully assess the impact of a disaster on an area, information about its predisaster status must be known. Aerial photography is one way of acquiring and recording such data

    Radiation-hard ASICs for optical data transmission in the ATLAS pixel detector

    Full text link
    We have developed two radiation-hard ASICs for optical data transmission in the ATLAS pixel detector at the LHC at CERN: a driver chip for a Vertical Cavity Surface Emitting Laser (VCSEL) diode for 80 Mbit/s data transmission from the detector, and a Bi-Phase Mark decoder chip to recover the control data and 40 MHz clock received optically by a PIN diode. We have successfully implemented both ASICs in 0.25 um CMOS technology using enclosed layout transistors and guard rings for increased radiation hardness. We present results from prototype circuits and from irradiation studies with 24 GeV protons up to 57 Mrad (1.9 x 10e15 p/cm2).Comment: 8th Tropical Seminar on Innovative Particle and Radiation Detectors, Siena, Italy (2002

    Corrosion and Passivation of Fe and FeN Films

    Get PDF
    The role of nitrogen in corrosion and passivation of thin Fe-N films was studied. Sputtered films with different levels of nitrogen were characterized for composition, conductivity, stress, and crystallinity. Corrosion and passivation of the films were evaluated by electrochemical measurements combined with in situ ellipsometry and ex situ x-ray photoelectron spectroscopy. The results indicate that in deaerated solutions the primary action of N is to reduce the catalytic activity of the surface for the hydrogen reaction and thereby reduce corrosion. In aerated solutions the corrosion rate increases with N content. Kinetics of the protective oxide formation as a function of potential, percent N, and the presence of borate buffer are discussed in detail. The work is relevant to the behavior of oxide-free Fe-N surfaces in contact with mild, nearly neutral electrolytes, such as could be used in fabrication of magnetic recording heads

    Double-crested cormorant colony effects on soil chemistry, vegetation structure and avian diversity

    Get PDF
    Effects of Double-crested Cormorants (Phalacrocorax auritus) on vegetation, soil chemistry and tree health have been documented from their breeding colonies in the northern breeding grounds of Canada and the United States (U.S.) but not for areas within the southeastern United States where breeding activity is relatively novel. We compared vegetation and tree metrics such as structure diversity, and soil chemistry among colony islands, uninhabited islands, and abandoned colony islands within Guntersville Reservoir, a temperate forest ecosystem. Avian diversity and community structure were also quantified on these islands. Concentrations of potassium (K), phosphorus (P) and nitrate (NO3 −) in soil were negatively related to cormorant use, while tree diversity was lower on historic (tree mean=4.35 ± 2.46 species) and colony (tree mean=3.91 ± 3.12 species) islands relative to reference islands (tree mean=9.11 ± 3.88 species). Canopy cover was less (min:\u3c20%), and midstories denser on colony and historic islands relative to reference islands. Avian diversity was significantly lower for colony islands (mean=6 ± 3 species) than both reference (11 ± 7 species) and historic (10 ± 7 species) islands. These effects of cormorant nesting can be seen even after 10 years of colony abandonment supporting that cormorants can have long-term effects on insular habitats in temperate forest ecosystems

    Geographic variation in sperm traits reflects predation risk and natural rates of multiple paternity in the guppy

    Get PDF
    Guppies (Poecilia reticulata) are models for understanding the interplay between natural and sexual selection. In particular, predation has been implicated as a major force affecting female sexual preferences, male mating tactics and the level of sperm competition. When predation is high, females typically reduce their preferences for showy males and engage more in antipredator behaviours, whereas males exploit these changes by switching from sexual displays to forced matings. These patterns are thought to account for the relatively high levels of multiple paternity in high-predation populations compared to low-predation populations. Here, we assess the possible evolutionary consequences of these patterns by asking whether variation in sperm traits reflect differences in predation intensity among four pairs of Trinidadian populations: four that experience relatively low levels of predation from a gape-limited predator and four that experience relatively high levels of predation from a variety of piscivores. We found that males in high-predation populations had faster swimming sperm with longer midpieces compared to males in low-predation populations. However, we found no differences among males in high- and low-predation populations with respect to sperm number, sperm head length, flagellum length and total sperm length

    Antigen depot is not required for alum adjuvanticity

    Get PDF
    Alum adjuvants have been in continuous clinical use for more than 80 yr. While the prevailing theory has been that depot formation and the associated slow release of antigen and/or inflammation are responsible for alum enhancement of antigen presentation and subsequent T- and B-cell responses, this has never been formally proven. To examine antigen persistence, we used the chimeric fluorescent protein EαGFP, which allows assessment of antigen presentation in situ, using the Y-Ae antibody. We demonstrate that alum and/or CpG adjuvants induced similar uptake of antigen, and in all cases, GFP signal did not persist beyond 24 h in draining lymph node antigen-presenting cells. Antigen presentation was first detectable on B cells within 6–12 h of antigen administration, followed by conventional dendritic cells (DCs) at 12–24 h, then finally plasmacytoid DCs at 48 h or later. Again, alum and/or CpG adjuvants did not have an effect on the magnitude or sequence of this response; furthermore, they induced similar antigen-specific T-cell activation in vivo. Notably, removal of the injection site and associated alum depot, as early as 2 h after administration, had no appreciable effect on antigen-specific T- and B-cell responses. This study clearly rules out a role for depot formation in alum adjuvant activity

    Morphology of the 12-micron Seyfert Galaxies: II. Optical and Near-Infrared Image Atlas

    Full text link
    We present 263 optical and near-infrared (NIR) images for 42 Seyfert 1s and 48 Seyfert 2s, selected from the Extended 12-micron Galaxy Sample. Elliptically-averaged profiles are derived from the images, and isophotal radii and magnitudes are calculated from these. We also report virtual aperture photometry, that judging from comparison with previous work, is accurate to roughly 0.05mag in the optical, and 0.07mag in the NIR. Our B-band isophotal magnitude and radii, obtained from ellipse fitting, are in good agreement with those of RC3. When compared with the B band, V, I, J, and K isophotal diameters show that the colors in the outer regions of Seyferts are consistent with the colors of normal spirals. Differences in the integrated isophotal colors and comparison with a simple model show that the active nucleus+bulge is stronger and redder in the NIR than in the optical. Finally, roughly estimated Seyfert disk surface brightnesses are significantly brighter in B and K than those in normal spirals of similar morphological type.Comment: 17 pgs including figures; Table 2 is a separate file. Complete Figure 1 is available by contacting the authors. Accepted for publication in ApJ
    • …
    corecore