1,442 research outputs found

    European - North American - Russian Federation Inland ENC Harmonization Group

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    In 2003, the Inland ENC Harmonization Group (IEHG) was formed to agree upon specifications for Inland ENCs that are suitable for all known Inland ENC data requirements for safe and efficient navigation in European and North American inland waterways and rivers. In 2004, the IEHG expanded to include Russian Federation. It is expected that South America will join IEHG in the near future. The overall framework for international Inland ENC standards includes: - Use IHO S-57 Edition 3.1 ā€˜maritimeā€™ ENC Product Specification, where applicable. - A minimum Inland ENC Product Specification that includes mandatory requirements for safety-of-navigation on inland waterways, worldwide. - An Inland ENC Encoding Guide that provides guidance on recommended object classes, attributes, and attribute values for encoding IENC data. - An Inland ENC Register for additional real-world, IENC object classes, attributes, and attribute values not already contained in IHO S-57Edition 3.1 Object Catalog. - Use of the Open ECDIS Forum (OEF) as a means of communication and for establishment of Register for Inland ENC object classes, attributes, and attribute values. - Align with the future IHO S-100 Geospatial Standard for hydrographic data. Depending on what IHO adopts as a future ā€˜maritimeā€™ ENC Product Specification (S-101), the Inland ENC Product Specification may become an application ā€œprofileā€ consisting of a feature catalogue, an application schema, and encoding. Or, there may be a there may be a need for a separate Inland ENC Product Specification (e.g., S-102). This paper will briefly review the status to world-wide inland ENC coverage and implementation, and discuss the implications for expanding the scope of the hydrographic applications to meet new requirements

    Formation of Jarosite in the Marwrth Vallis Region of Mars by Weathering Within Paleo-Ice Deposits

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    Here we report new detections of jarosite in the Mawrth Vallis region of Mars. These newly recognized deposits expand the known occurrences of sulfates [1-2] in the region and further expand the already considerable geologic-mineralogic diversity of the Mawrth Vallis area [3-6]. The occurrence of sulfates such as jarosite in geologic contact with thick deposits of phyllosilicates in the Mawrth Vallis area is a relatively rare case on Mars where the enigmatic transition from an early phyllosilicateforming era to a younger sulfate-forming era [7] can be explored. We propose an ice-weathering model which can potentially explain the formation of jarosite-silicakaolinite within acidic ice deposits

    Selective Oligonucleotide and MRNA Pull-Down with Shielded Covalent Probes

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    Shielded covalent (SC) probes combine programmable base pairing, molecular conformation change, and activatable covalent crosslinking to achieve selective and durable capture of nucleic acid targets, including efficient discrimination of SNPs. Capture yields appear consistent with the thermodynamics of probe/target hybridization, allowing rational probe design. We will demonstrate RNA pull-down using surface-immobilized SC probes, exploiting covalent target capture to remove unwanted material using stringent washes, and then reversing the crosslinks to recover the targets. RNA pull-downs using SC probes will provide a powerful framework for exploring the in vivo binding partners of RNAs

    Calculation of two-dimensional turbulent flow fields

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    Navier-Stokes equation solutions for two- dimensional turbulent flow fields of compressible viscous flui

    The Carbonates in ALH 84001 Record the Evolution of the Martian Atmosphere Through Multiple Formation Events

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    Current Martian conditions restrict the presence of liquid water due to low temperatures (approx 210K), a thin atmosphere (approx 7mb), and intense UV radiation. However, past conditions on Mars may have been different with the possibility that the ancient Martian climate was warm and wet with a dense CO2 atmosphere. The cycling of carbon on Mars through atmospheric CO2 and carbonate minerals is critical for deciphering its climate history. In particular stable isotopes contained in carbonates can provide information of their origin and formation environment as well as possibly hinting at the composition of global reservoirs such as atmospheric CO2. Martian meteorite ALH 84001 contains widely studied carbonate rosettes that have been dated to approx. 3.9 Ga and have been used to interpret climatic conditions present at that time. However, there is mount-ing evidence for multiple episodes of carbonate formation in ALH 84001 with potentially distinct isotopic compositions. This study seeks to tease out these different carbonate assemblages using stepped phosphoric acid dissolution and analysis of carbon and triple oxygen stable isotopes. In addition, we report SIMS analyses of the delta O-18 several petrographically unusual carbonate phases in the meteorite

    Exploring the Cloud Icy Early Mars Hypothesis Through Geochemistry and Mineralogy

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    While ancient fluvial channels have long been considered strong evidence for early surface water on Mars, many aspects of the fluvial morphology and occurrence suggest that they formed in relatively water limited conditions (com-pared to Earth) and that climatic excursions allowing for surface water might have been short-lived. Updated results mapping valley networks at higher resolution have changed this paradigm, showing that channels are much more abundant and wide-spread, and of higher order than was previously recognized, suggesting that Mars had a dense enough atmosphere and warm enough climate to allow channel formation up to 3.6-3.8 Ga. This revised view of the ancient martian climate might be broadly consistent with a climate history of Mars devised from infrared remote sensing of surface minerals, suggesting that widespread clay minerals formed in the Noachian, giving way to a sulfur-dominated surface weathering system by approx. 3.7 Ga

    Carbon Isotope Systematics in Mineral-Catalyzed Hydrothermal Organic Synthesis Processes at High Temperature and Pressures

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    Observation of methane in the Martian atmosphere has been reported by different detection techniques. Reduction of CO2 and/or CO during serpentization by mineral surface catalyzed Fischer-Tropsch Type (FTT) synthesis may be one possible process responsible for methane generation on Mars. With the evidence a recent study has discovered for serpentinization in deeply buried carbon rich sediments, and more showing extensive water-rock interaction in Martian history, it seems likely that abiotic methane generation via serpentinization reactions may have been common on Mars. Experiments involving mineral-catalyzed hydrothermal organic synthesis processes were conducted at 750 C and 5.5 Kbars. Alkanes, alcohols and carboxylic acids were identified as organic compounds. No "isotopic reversal" of delta C-13 values was observed for alkanes or carboxylic acids, suggesting a different reaction pathway than polymerization. Alcohols were proposed as intermediaries formed on mineral surfaces at experimental conditions. Carbon isotope data were used in this study to unravel the reaction pathways of abiotic formation of organic compounds in hydrothermal systems at high temperatures and pressures. They are instrumental in constraining the origin and evolution history of organic compounds on Mars and other planets

    The Chemical Origin of Behavior is Rooted in Abiogenesis

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    We describe the initial realization of behavior in the biosphere, which we term behavioral chemistry. If molecules are complex enough to attain a stochastic element to their structural conformation in such as a way as to radically affect their function in a biological (evolvable) setting, then they have the capacity to behave. This circumstance is described here as behavioral chemistry, unique in its definition from the colloquial chemical behavior. This transition between chemical behavior and behavioral chemistry need be explicit when discussing the root cause of behavior, which itself lies squarely at the origins of life and is the foundation of choice. RNA polymers of sufficient length meet the criteria for behavioral chemistry and therefore are capable of making a choice

    Perceptions and responses to climate policy risks among California farmers

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    This paper considers how farmers perceive and respond to climate change policy risks, and suggests that understanding these risk responses is as important as understanding responses to biophysical climate change impacts. Based on a survey of 162 farmers in California, we test three hypotheses regarding climate policy risk: (1) that perceived climate change risks will have a direct impact on farmer\u27s responses to climate policy risks, (2) that previous climate change experiences will influence farmer\u27s climate change perceptions and climate policy risk responses, and (3) that past experiences with environmental policies will more strongly affect a farmer\u27s climate change beliefs, risks, and climate policy risk responses. Using a structural equation model we find support for all three hypotheses and furthermore show that farmersā€™ negative past policy experiences do not make them less likely to respond to climate policy risks through participation in a government incentive program. We discuss how future research and climate policies can be structured to garner greater agricultural participation. This work highlights that understanding climate policy risk responses and other social, economic and policy perspectives is a vital component of understanding climate change beliefs, risks and behaviors and should be more thoroughly considered in future work
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