New data on regularities of fault activation in the Baikal rift system and the adjacent territory     

S. I. Sherman 《Doklady Earth Sciences》2007,415(1):794-798

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Improved methods for isolating and validating indigenous biomarkers in Precambrian rocks   总被引：1，自引：0，他引：1  

Laura S. Sherman  Jacob R. Waldbauer  Roger E. Summons   《Organic Geochemistry》2007,38(12):1987-2000

Hydrocarbon biomarkers in highly mature Precambrian rocks have the potential to provide important information about the diversity ecology, and evolution of early life, but studying them presents special analytical challenges. Extractable hydrocarbons are present in Archean and most Paleoproterozoic sedimentary rocks in such trace concentration that even slight contamination from petroleum-derived materials in situ or during drilling, storage, sampling, handling and laboratory analysis would compromise the results and, thereby, any consequent inferences. Here we report protocols that we have developed for the analysis of cores from several recently completed deep-time scientific drilling initiatives. By paying special attention to cutting, cleaning, crushing and extraction, it is possible to significantly reduce laboratory blanks to acceptable levels. When these methods are utilized, meaningful variations in the patterns of biomarkers over stratigraphic and lithologic boundaries provide compelling evidence for syngeneity.  相似文献   

Photogrammetric application of viking orbital photography     

Sherman S.C Wu  A.A Elassal  Raymond Jordan  F.J Schafer 《Planetary and Space Science》1982,30(1):45-55

Special techniques are described for the photogrammetric compilation of topographic maps and profiles from stereoscopic photographs taken by the two Viking Orbiter spacecraft. These techniques were developed because the extremely narrow field of view of the Viking cameras precludes compilation by conventional photogrammetric methods. The techniques adjust for internal consistency the Supplementary Experiment Data Record (SEDR—the record of spacecraft orientation when photographs were taken) and the computation of geometric orientation parameters of the stereo models. A series of contour maps of Mars is being compiled by these new methods using a wide variety of Viking Orbiter photographs, to provide the planetary research community with topographic information.  相似文献   

Multistage, stochastic models of the cancer process: A general theory for calculating tumor incidence     

C. J. Portier  C. D. Sherman  A. Kopp-Schneider 《Stochastic Environmental Research and Risk Assessment (SERRA)》2000,14(3):173-179

 The use of complicated models of the cancer process has been limited by the need to have a mathematical framework allowing for a general expansion of the theory of carcinogenesis while maintaining numerically tractable results. A system of ordinary differential equations is derived for calculating tumor incidence in multistage models of carcinogenesis. The resulting system of equations is applicable to nonhomogenous processes (i.e. ones in which the rates change with time, age, etc.). In addition, a solution is given for the case of instantaneous initiation. These formulae can easily be coupled with physiologically-based pharmacokinetic models to link biomarkers of exposure to cancer risks. An example is presented.  相似文献   

Stakeholder engagement in adaptation interventions: an evaluation of projects in developing nations     

Mya H. Sherman  James Ford 《Climate Policy》2013,13(3):417-441

Institution-oriented, top-down and community-oriented, bottom-up stakeholder approaches are evaluated for their ability to enable or constrain the implementation of adaptation in developing nations. A systematic review approach is used evaluate the project performance of 18 adaptation projects by three of the Global Environment Facility's (GEF) adaptation programmes (the Strategic Priority for Adaptation (SPA), the Special Climate Change Fund (SCCF), and the National Adaptation Programs of Action (NAPA)) according to effectiveness, efficiency, equity, legitimacy, flexibility, sustainability, and replicability. The ten SPA projects reviewed performed highest overall, especially with regards to efficiency, legitimacy, and replicability. The five SCCF projects performed the highest in equity, flexibility, and sustainability, and the three NAPA-related projects were the highest-performing projects with regards to effectiveness. A comparison of top-down and bottom-up approaches revealed that community stakeholder engagement in project design and implementation led to higher effectiveness, efficiency, equity, flexibility, legitimacy, sustainability, and replicability. Although low institutional capacity constrained both project success and effective community participation, projects that hired international staff to assist in implementation experienced higher overall performance. These case studies also illustrate how participatory methods can fail to genuinely empower or involve communities in adaptation interventions in both top-down and bottom-up approaches. It is thus crucial to carefully consider stakeholder engagement strategies in adaptation interventions.Policy relevanceWhile adaptation is now firmly on the policy and research agenda, actual interventions to reduce vulnerability and enhance resilience remain in their infancy, and there is limited information on the factors that influence the successful implementation of adaptation in developing areas. Engaging stakeholders in assessing vulnerability and implementing adaptation interventions is widely regarded to be an important factor for adaptation implementation and success. However, no study has evaluated the effects of stakeholder engagement in the actual implementation of adaptation initiatives. Effective stakeholder engagement is challenging, especially in a developing nation setting, due to high levels of poverty, inadequate knowledge on adaptation options, weak institutions, and competing interests to address more immediate problems related to poverty and underdevelopment. In this context, this article documents and characterizes stakeholder engagement in adaptation interventions supported through the GEF, examining how top-down or bottom-up stakeholder approaches enable or constrain project performance.  相似文献   

STREAM MORPHOLOGIC IMPACT OF AND RECOVERY FROM MAJOR FLOODING IN NORTH-CENTRAL NEVADA     

Tom Myers  Sherman Swanson 《自然地理学》2013,34(5):431-445

Major floods cause channel changes ranging from complete cross-sectional change to small fluctuations in pool area. We used stream cross-section data on 30 heavily grazed rangeland streams in north-central Nevada to assess changes over a climatically variable 14-year period. There was an insufficient range in ungulate damage to consider differences caused by grazing. Flooding with return intervals exceeding 50 years caused major change on approximately 25% of the surveyed streams regardless of initial stream type. One-quarter of the changed streams continued to experience cross-sectional change during a six- to eight-year period of low-to-normal flows. On these streams, upper banks either receded to expose a new, lower floodplain or flattened to a less vertical slope. On streams that did not change type, flooding substantially reduced pool area, which did not recover during the succeeding period, presumably because energy was insufficient to form pools. High flows flushed fine sediment from the streams that did not change type, but fines returned in six years of low flows. Stream classification did not usefully predict major changes, channel evolution after the change, or differences in the effect of flooding on pools among streams that did not change.  相似文献   

Calibrating adaptive antenna arrays for high-integrity GPS     

David S. De Lorenzo  Sherman C. Lo  Per K. Enge  Jason Rife 《GPS Solutions》2012,16(2):221-230

A major challenge in using GPS guidance for aircraft final approach and landing is to reject interference that can jam reception of the GPS signals. Antenna arrays, which use space–time adaptive processing (STAP), significantly improve the signal to interference plus noise ratio, but at the possible expense of distorting the received signals, leading to timing biases that may degrade navigation performance. Rather than a sophisticated calibration approach to remove biases introduced by STAP, this paper demonstrates that a relatively compact calibration strategy can substantially reduce navigation biases, even under elevated interference conditions. Consequently, this paper develops an antenna bias calibration strategy for two classes of adaptive array algorithm and validates this method using both simulated and experimental data with operational hardware in the loop. A proof-of-concept system and an operational prototype are described, which implement the adaptive antenna algorithms and deterministic corrections. This investigation demonstrates that systems with adaptive antenna arrays can approach the accuracy and integrity requirements for automatic aircraft landing, and in particular for sea-based landing on board aircraft carriers, while simultaneously providing significant attenuation of interference. Evidence suggests that achieving these goals is possible with minimal restrictions on system hardware configuration—specifically, limitations on the permissible level of antenna anisotropy and the use of sufficient analog-to-digital converter resolution.  相似文献   

Biodiversity and abundance of the zooplankton of the Northeast Shelf ecosystem     

Sherman  K.; Solow  A.; Jossi  J.; Kane  J. 《ICES Journal of Marine Science》1998,55(4):730-738

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Geospatial cryptography: enabling researchers to access private,spatially referenced,human subjects data for cancer control and prevention     

Jacquez  Geoffrey M.  Essex  Aleksander  Curtis  Andrew  Kohler  Betsy  Sherman  Recinda  El Emam  Khaled  Shi  Chen  Kaufmann  Andy  Beale  Linda  Cusick  Thomas  Goldberg  Daniel  Goovaerts  Pierre 《Journal of Geographical Systems》2017,19(3):197-220

Journal of Geographical Systems - As the volume, accuracy and precision of digital geographic information have increased, concerns regarding individual privacy and confidentiality have come to the...  相似文献   

High-temperature heat capacity of Co3O4 spinel: thermally induced spin unpairing transition     

K. Mocala  A. Navrotsky  D. M. Sherman 《Physics and Chemistry of Minerals》1992,19(2):88-95

A strong anomaly was found in the heat capacity of Co₃O₄ between 1000 K and the decomposition temperature. This anomaly is not related to the decomposition of Co₃O₄ to CoO. The measured entropy of transition, S=46±4 J mol^-1 K^-1 of Co₃O₄, supports the interpretation that this anomaly reflects a spin unpairing transition in octahedrally coordinated Co³⁺ cations. Experimental values of heat capacity, heat content and entropy of Co₃O₄ in the high temperature region are provided. The enthalpy of the spin unpairing transition is 53±4 kJ mol^-1 of Co₃O₄.  相似文献