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Parabolic planar compound refractive lenses (CRLs) made from glassy carbon by means of laser ablation are presented. They have radii of curvatures of 5 and 200 mu m and geometric apertures of 40 and 900 mu m, respectively. The numbers of biconcave elements in the CRLs were 4, 7, and 200. The planar lenses allow formation of a linear focus of length comparable with the depths of their profiles. Usa

Stratospheric ozone levels are near their lowest point since measurements began, so current ultraviolet-B (UV-B) radiation levels are thought to be close to their maximum. Total stratospheric content of ozone-depleting substances is expected to reach a maximum before the year 2000. All other things being equal, the current ozone losses and related UV-B increases should be close to their maximum. I

Remnants of more than 3 million transposable elements, primarily retroelements, comprise nearly half of the human genome and have generated much speculation concerning their evolutionary significance. We have exploited the draft human genome sequence to examine the distributions of retroelements on a genome-wide scale. Here we show that genomic densities of 10 major classes of human retroelements

The Transition Radiation Tracker (TRT) sits at the outermost part of the ATLAS Inner Detector, encasing the Pixel Detector and the Semi-Conductor Tracker (SCT). The TRT combines charged particle track reconstruction with electron identification capability. This is achieved by layers of xenonfilled straw tubes with periodic radiator foils or fibers providing TR photon emission. The design and choic

The gene responsible for X-linked agammaglobulinemia (XLA) has been recently identified to code for a cytoplasmic tyrosine kinase (Bruton's agammaglobulinemia tyrosine kinase, BTK), required for normal B cell development. BTK, like many other cytoplasmic tyrosine kinases, contains Src homology domains (SH2 and SH3), and catalytic kinase domain. SH3 domains are important for the targeting of signal

Popular Abstract in Swedish I denna avhandling studeras skolsituationen för elever med båda föräldrarna födda utomlands. Samband mellan elevernas bakgrund, övriga faktorer som i tidigare forskning visat sig betydelsefulla och skolresultat identifieras och analyseras. Studien utgår från de data som insamlades inom ramen för "Det nationella programmet för utvärdering", som genomfördes 1992. Utvärder

We simulate two-dimensional lattices of pulse-coupled oscillators with random natural frequencies, resembling pacemaker cells in the heart. As coupling increases, this system seems to undergo two phase transitions in the thermodynamic limit. First, the largest cluster of frequency entrained oscillators becomes macroscopic. Second, all oscillators frequency entrain, except possibly some isolated on

Galectins are defined by a conserved beta-galactoside binding site, which has been linked to many of their important functions in e.g. cell adhesion, signaling and intracellular trafficking. Weak adjacent sites may enhance or decrease affinity for natural beta-galactoside containing glycoconjugates, but little is known about the biological role of this modulation of affinity (fine specificity). We

SO2 plays an important role in the atmospheric chemistry of the Earth, Venus, and Io. This paper presents photoabsorption cross sections of SO2 from 213 to 325 nm at 198 K, encompassing the (C) over tilde B-1(2) - (X) over tilde (1)A(1) and (B) over tilde B-1(1) - (X) over tilde (1)A(1) electronic bands. These measurements are part of a series of measurements over the 160 to 300 K temperature rang

Endocrine-disrupting chemicals are known to alter the fitness of individual organisms via changes in growth, behavior, and reproduction. It is largely unknown, however, whether these effects cascade through the food web and indirectly affect other, less sensitive organisms. The authors present results from a mesocosm experiment whereby the effects of the synthetic estrogen 17α-ethinylestradiol (EE