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<jats:p> The first fully automated design and experimental validation of a novel sequence for an entire protein is described. A computational design algorithm based on physical chemical potential functions and stereochemical constraints was used to screen a combinatorial library of 1.9 × 10 <jats:sup>27</jats:sup> possible amino acid sequences for compatibility with the design target, a ββα protein motif based on the polypeptide backbone structure of a zinc finger domain. A BLAST search shows that the designed sequence, full sequence design 1 (FSD-1), has very low identity to any known protein sequence. The solution structure of FSD-1 was solved by nuclear magnetic resonance spectroscopy and indicates that FSD-1 forms a compact well-ordered structure, which is in excellent agreement with the design target structure. This result demonstrates that computational methods can perform the immense combinatorial search required for protein design, and it suggests that an unbiased and quantitative algorithm can be used in various structural contexts. </jats:p>

<jats:p>Abundant fossil meteorites in marine, condensed Lower Ordovician limestones from Kinnekulle, Sweden, indicate that accretion rates of meteorites were one to two orders of magnitude higher during an interval of the Early Ordovician than at present. Osmium isotope and iridium analyses of whole-rock limestone indicate a coeval enhancement of one order of magnitude in the influx rate of cosmic dust. Enhanced accretion of cosmic matter may be related to the disruption of the L chondrite parent body around 500 million years ago.</jats:p>

<jats:p> The <jats:sup>12</jats:sup> C/ <jats:sup>13</jats:sup> C, <jats:sup>14</jats:sup> N/ <jats:sup>15</jats:sup> N, and <jats:sup>32</jats:sup> S/ <jats:sup>34</jats:sup> S isotope ratios in comet Hale-Bopp (C/1995 O1) were determined through observations taken with the James Clerk Maxwell Telescope. Measurements of rare isotopes in HCN and CS revealed isotope ratios of H <jats:sup>12</jats:sup> CN/H <jats:sup>13</jats:sup> CN = 111 ± 12, HC <jats:sup>14</jats:sup> N/HC <jats:sup>15</jats:sup> N = 323 ± 46, and C <jats:sup>32</jats:sup> S/C <jats:sup>34</jats:sup> S = 27 ± 3. Within the measurement uncertainties, the isotopic ratios are consistent with solar system values. The cometary volatiles thus have an origin in the solar system and show no evidence for an interstellar component. </jats:p>

<jats:p>Measurements of total ozone at Faraday, Antarctica (65°S), by a visible spectrometer show a winter maximum. This new observation is consistent with the descent of air within the polar vortex during early winter, together with ozone depletion starting in midwinter. Chemical depletion at these latitudes in midwinter is suggested by existing satellite observations of enhanced chlorine monoxide and reduced ozone above 100 hectapascals and by reduced ozone in sonde profiles. New three-dimensional model calculations for 1994 confirm that chemical ozone depletion started in June at the sunlit vortex edge and became substantial by late July. This would not have been observed by most previous techniques, which either could not operate in winter or were closer to the Pole.</jats:p>

<jats:p> An optical storage technique based on time-domain holography for the rapid recording and readout of page-formatted digital data is demonstrated. Storage of 356 kilobits of data was achieved at a single spatial location in a rare-earth–doped crystal. The digital data were recorded and accurately retrieved at a peak rate of 300 megabits per second without the use of error-correcting codes. The system's raw bit error rate is about 10 <jats:sup>−</jats:sup> <jats:sup>7</jats:sup> . This low bit error rate was achieved by a detection scheme for extraction of binary data. These results have implications for dynamic optical memory. </jats:p>