Using 1-Hz GPS data to measure deformations caused by the Denali fault earthquake   总被引：13，自引：0，他引：13  

Larson KM  Bodin P  Gomberg J 《Science (New York, N.Y.)》2003,300(5624):1421-1424

The 3 November 2002 moment magnitude 7.9 Denali fault earthquake generated large, permanent surface displacements in Alaska and large-amplitude surface waves throughout western North America. We find good agreement between strong ground-motion records integrated to displacement and 1-hertz Global Positioning System (GPS) position estimates collected approximately 140 kilometers from the earthquake epicenter. One-hertz GPS receivers also detected seismic surface waves 750 to 3800 kilometers from the epicenter, whereas these waves saturated many of the seismic instruments in the same region. High-frequency GPS increases the dynamic range and frequency bandwidth of ground-motion observations, providing another tool for studying earthquake processes.  相似文献   

Epidemiology. DNA identifications after the 9/11 World Trade Center attack     

Biesecker LG  Bailey-Wilson JE  Ballantyne J  Baum H  Bieber FR  Brenner C  Budowle B  Butler JM  Carmody G  Conneally PM  Duceman B  Eisenberg A  Forman L  Kidd KK  Leclair B  Niezgoda S  Parsons TJ  Pugh E  Shaler R  Sherry ST  Sozer A  Walsh A 《Science (New York, N.Y.)》2005,310(5751):1122-1123

The attack on the World Trade Center on 9/11/2001 challenged current approaches to forensic DNA typing methods. The large number of victims and the extreme thermal and physical conditions of the site necessitated special approaches to the DNA-based identification. Because of these and many additional challenges, new procedures were created or modified from routine forensic protocols. This effort facilitated the identification of 1594 of the 2749 victims. In this Policy Forum, the authors, who were were members of the World Trade Center Kinship and Data Analysis Panel, review the lessons of the attack response from the perspective of DNA forensic identification and suggest policies and procedures for future mass disasters or large-scale terrorist attacks.  相似文献   

Impacts of fine root turnover on forest NPP and soil C sequestration potential   总被引：2，自引：0，他引：2  

Matamala R  Gonzàlez-Meler MA  Jastrow JD  Norby RJ  Schlesinger WH 《Science (New York, N.Y.)》2003,302(5649):1385-1387

Estimates of forest net primary production (NPP) demand accurate estimates of root production and turnover. We assessed root turnover with the use of an isotope tracer in two forest free-air carbon dioxide enrichment experiments. Growth at elevated carbon dioxide did not accelerate root turnover in either the pine or the hardwood forest. Turnover of fine root carbon varied from 1.2 to 9 years, depending on root diameter and dominant tree species. These long turnover times suggest that root production and turnover in forests have been overestimated and that sequestration of anthropogenic atmospheric carbon in forest soils may be lower than currently estimated.  相似文献   

Widespread triggering of nonvolcanic tremor in California     

Gomberg J  Rubinstein JL  Peng Z  Creager KC  Vidale JE  Bodin P 《Science (New York, N.Y.)》2008,319(5860):173

We identified seven locations on or near the transform plate boundary in California where nonvolcanic tremor was triggered by the 2002 Denali earthquake. This result implies that the conditions essential for nonvolcanic tremor exist in a range of tectonic environments. Models explaining tremor typically require conditions endemic to subduction zones, that is, high temperatures and fluid pressures, because previously tremor was nearly exclusively documented in subduction zones. The absence of tremor in geothermal areas is inconsistent with such models. Additionally, we found no correlation between creeping or locked faults and tremor, contrary to predictions of frictional models of tremor.  相似文献   

Gender differences and performance in science     

Muller CB  Ride SM  Fouke J  Whitney T  Denton DD  Cantor N  Nelson DJ  Plummer J  Busch-Vishniac I  Meyers C  Rosser SV  Schiebinger L  Roberts E  Burgess D  Beeson C  Metz SS  Sanders L  Watford BA  Ivey ES  Frank Fox M  Wettack S  Klawe M  Wulf WA  Girgus J  Leboy PS  Babco EL  Shanahan B  Didion C  Chubin DE  Frize M  Ganter SL  Nalley EA  Franz J  Abruña HD  Strober MH  Zimmer Daniels J  Carter EA  Rhodes JH  Schrijver I  Zakian VA  Simons B  Martin U  Boaler J  Jolluck KR  Mankekar P  Gray RM  Conkey MW  Stansky P  Xie A  Martin P 《Science (New York, N.Y.)》2005,307(5712):1043

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Abrupt temperature changes in the Western Mediterranean over the past 250,000 years     

Martrat B  Grimalt JO  Lopez-Martinez C  Cacho I  Sierro FJ  Flores JA  Zahn R  Canals M  Curtis JH  Hodell DA 《Science (New York, N.Y.)》2004,306(5702):1762-1765

A continuous high-resolution Western Mediterranean sea surface temperature (SST) alkenone record spanning the past 250,000 years shows that abrupt changes were more common at warming than at cooling. During marine isotope stage (MIS) 6, SST oscillated following a stadial-interstadial pattern but at lower intensities and rates of change than in the Dansgaard/Oeschger events of MIS 3. Some of the most prominent events occurred over MISs 5 and 7, after prolonged warm periods of high stability. Climate during the whole period was predominantly maintained in interglacial-interstadial conditions, whereas the duration of stadials was much shorter.  相似文献   

Block Estimating of Spatial Yield Data and its Uncertainty     

Han  Shufeng  Schneider  Sally M.  Evans  Robert G.  Davenport  Joan R. 《Precision Agriculture》2004,5(1):73-84

On-the-go yield monitors have been available for both grain and bulk crops. Most of the yield monitors today provide yield measurement at a fixed time interval. Conversion of these point yield data into raster yield maps for further analysis is necessary. In this study, a data-blocking procedure is proposed to create raster yield maps from point yield data. The blocking procedure includes: (1) converting the fixed-time-interval data into fixed-distance-interval data; (2) using a moving average algorithm to estimate a cell value when there are sufficient data points within the cell; (3) using a geostatistical algorithm to estimate a cell value when there are not enough data points within the cell but values of its neighboring cells are known; and (4) calculating an uncertainty index for each cell value estimation. An example application of the yield-blocking procedure with potato harvest data in 1996 was given.  相似文献   

Marine fish egg hydration is aquaporin-mediated     

Fabra M  Raldúa D  Power DM  Deen PM  Cerdà J 《Science (New York, N.Y.)》2005,307(5709):545

The positive buoyancy of marine fish eggs in sea water, allowed by hydration of the oocyte, is critical for their survival and dispersion in the ocean. We isolated an aquaporin, SaAQP1o, that belongs to a unique subfamily of aquaporin-1-like channels specifically evolved in teleosts and mainly expressed in the ovary. We further show that hormone-induced fish oocyte hydration is a highly controlled process based on the interplay between protein hydrolysis and the translocation of SaAQP1o to the plasma membrane, indicating a specialized physiological role for this aquaporin.  相似文献   

Tissue-specific enhancement of xenobiotic detoxification enzymes in mice by dietary rosemary extract     

Keith W. Singletary  Joan T. Rokusek 《Plant foods for human nutrition (Dordrecht, Netherlands)》1997,50(1):47-53

Plant foods contain nutritive and minor, nonnutritive components capable of inhibiting experimental carcinogenesis. Many of these cancer-protective extracts act by enhancing the activities of enzymes that can detoxify reactive substances. In the present study an extract of the spice plant rosemary was fed at concentrations of 0.3% and 0.6% (by weight) for 4 weeks to female A/J mice prior to determination of the activities of the detoxification enzymes glutathione-S-transferase (GST) and NAD(P)H: quinone reductase (QR) in lung, liver and stomach. Liver activities of GST and QR, and stomach GST activity were significantly increased in animals fed diets containing rosemary extract. However, diets supplemented with rosemary extract did not affect lung GST and QR activities. These results indicate that components of rosemary extract have the potential to protect mouse liver and stomach from carcinogenic or toxic agents.  相似文献   

Puerarin and conjugate bases as radical scavengers and antioxidants: molecular mechanism and synergism with beta-carotene   总被引：2，自引：0，他引：2  

Han RM  Tian YX  Becker EM  Andersen ML  Zhang JP  Skibsted LH 《Journal of agricultural and food chemistry》2007,55(6):2384-2391

The 4'-hydroxyl group of puerarin, a C-glycoside of the isoflavonoid daidzein, was shown, using 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) radical cation and stopped-flow spectroscopy and by comparison with the 7-propylpuerarin (A ring derivative) and 4'-propylpuerarin (B ring derivative), to be a more efficient radical scavenger as compared to the 7-hydroxyl group by a factor of 2, a difference increasing upon deprotonation. The difference in radical scavenging agreed with the oxidation potentials (cyclic voltammetry in acetonitrile, 0.1 M Bu4NBF4 at 25 degrees C): E/mV=862+/-3 for puerarin, 905+/-10 for 7-propylpuerarin, and 1064+/-2 for 4'-propylpuerarin relative to ferrocene/ferricenium. In aqueous solution, the reduction potential was shown to decrease for increasing pH, and deprotonation of the 4'-hydroxyl group increased radical scavenging more than deprotonation of the 7-hydroxyl group. The 7-hydroxyl was found to be more acidic (pKa1=7.20+/-0.01 in puerarin and pKa=7.23+/-0.01 in 4'-propylpuerarin) than the 4'-hydroxyl group (pKa2=9.84+/-0.08 in puerarin and pKa=9.51+/-0.02 in 7-propylpuerarin); aqueous solution, ionic strength of 0.1, and 25 degrees C. In phosphatidyl choline liposome of pH 7.4, puerarin and beta-carotene each showed a modest antioxidant activity measured as prolongation of the lag phase for formation of conjugate dienes and using the water-soluble radical initiator APPH with effects of puerarin and beta-carotene being additive. For the lipophilic initiator AMVN, the antioxidative effect decreased for puerarin and increased for beta-carotene as compared to APPH and showed a clear synergism. A regeneration of beta-carotene, effective in the liposome lipid phase as antioxidant, from the cation radical by deprotonated forms of puerarin was demonstrated in 9:1 chloroform/methanol using laser flash photolysis with k2=2.7x10(4) L mol-1 s-1 for the bimolecular process between the cation radical and the puerarin dianion.  相似文献