745 research outputs found

    Bogged Down Trying to Define Federal Wetlands

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    This article examines these cases as well as the history, policies, and rationales behind identifying and conserving wetlands. It proposes a unique analytical method for valuation of wetlands. Under the proposed analysis, government agencies and landowners would be required to prepare economic impact statements containing cost/benefit analyses measuring the effects of wetlands delineations upon land values. These analyses would provide the basis for determining the value of preserving wetlands ecosystems as well as the basis for determining fair compensation payable to landowners in the event they suffer land use or income loss as a result of wetlands delineations

    The impact of memory demands on audience design during language production.

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    Abstract Speakers often tailor their utterances to the needs of particular addressees-a process called audience design. We argue that important aspects of audience design can be understood as emergent features of ordinary memory processes. This perspective contrasts with earlier views that presume special processes or representations. To support our account, we present a study in which Directors engaged in a referential communication task with two independent Matchers. Over several rounds, the Directors instructed the Matchers how to arrange a set of picture cards. For half the triads, the Directors' card categories were initially distributed orthogonally by Matcher (e.g. Directors described birds and dogs with one Matcher and fish and frogs with the other). For the other triads, the Directors' card categories initially overlapped across Matchers (e.g. Directors described two members of each category with each Matcher). We predicted that the orthogonal configuration would more readily allow Directors to encode associations between particular cards and particular Matchers-and thus allow those Directors to provide more evidence for audience design. Content analyses of Directors' utterances from two final rounds supported our prediction. We suggest that audience design depends on the memory representations to which speakers have ready access given the time constraints of routine conversation.

    Middle to late Cenozoic basin evolution in the western Alborz Mountains: Implications for the onset of collisional deformation in northern Iran

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    Oligocene-Miocene strata preserved in synclinal outcrop belts of the western Alborz Mountains record the onset of Arabia-Eurasia collision-related deformation in northern Iran. Two stratigraphic intervals, informally named the Gand Ab and Narijan units, represent a former basin system that existed in the Alborz. The Gand Ab unit is composed of marine lagoonal mudstones, fluvial and alluvial-fan clastic rocks, fossiliferous Rupelian to Burdigalian marine carbonates, and basalt flows yielding ^(40)Ar/^(39)Ar ages of 32.7 ± 0.3 and 32.9 ± 0.2 Ma. The Gand Ab unit is correlated with the Oligocene–lower Miocene Qom Formation of central Iran and is considered a product of thermal subsidence following Eocene extension. The Narijan unit unconformably overlies the Gand Ab unit and is composed of fluvial-lacustrine and alluvial fan sediments exhibiting contractional growth strata. We correlate the Narijan unit with the middle to upper Miocene Upper Red Formation of central Iran on the basis of lithofacies similarities, stratigraphic position, and an 8.74 ± 0.15 Ma microdiorite dike (^(40)Ar/^(39)Ar) that intruded the basal strata. Deformation timing is constrained by crosscutting relationships and independent thermochronological data. The Parachan thrust system along the eastern edge of the ancestral Taleghan-Alamut basin is cut by dikes dated at 8.74 ± 0.15 Ma to 6.68 ± 0.07 Ma (^(40)Ar/^(39)Ar). Subhorizontal gravels that unconformably overlie tightly folded and faulted Narijan strata are capped by 2.86 ± 0.83 Ma (^(40)Ar/^(39)Ar) andesitic lava flows. These relationships suggest that Alborz deformation had migrated southward into the Taleghan-Alamut basin by late Miocene time and shifted to its present location along the active range front by late Pliocene time. Data presented here demonstrate that shortening in the western Alborz Mountains had started by late middle Miocene time. This estimate is consistent with recent thermochronological results that place the onset of rapid exhumation in the western Alborz at ∼12 Ma. Moreover, nearly synchronous Miocene contraction in the Alborz, Zagros Mountains, Turkish-Iranian plateau, and Anatolia suggests that the Arabia-Eurasia collision affected a large region simultaneously, without a systematic outward progression of mountain building away from the collision zone

    Inhibition of Insulin Amyloid Formation by Small Organofluorine Molecules

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    Many human diseases, including Alzheimer’s disease (AD) and diabetes mellitus type II (DM) have been connected to protein misfolding and the formation of highly ordered fibrillar protein aggregates called amyloids. DM is characterized by an overproduction of insulin to the point of insulin resistance in the body. The protein deposits in the AD-affected brain is related to the aggregation of tau protein and amyloid β (Aβ) peptide. Amyloid fibrils and their oligomeric precursors are known to be cytotoxic inducing neurological cell death. Recent clinical studies have suggested a link between Alzheimer’s disease and DM based on the fact that DM patients have double the risk of developing Alzheimer’s disease. It is believed that the increased risk of heart disease and stroke linked to DM causes further damage to blood vessels that eventually target the brain. Due to the continued rise of both diseases among aging adults, there is considerable interest in eluciditating the similarities and differences in the mechanism of amyloid formation of insulin and Aβ and understanding how the oligomeric state of the two peptides affect each other’s aggregation and role. Our group has already designed and experimentally tested a broad variety of small molecules, including organofluorines that effectively inhibit the self-assembly of Aβ. As an extension of these earlier studies the same group of organofluorine molecules are being tested for their inhibitory activity in the formation of insulin fibrils. The aggregation of insulin with/without these potential inhibitors at 37°C and pH=7.4 are followed by a kinetic Thioflavin T (ThT) fluorescence assay and visualized by Atomic Force Microscopy (AFM). The small molecule-insulin interactions are also investigated by electrospray mass spectrometry (HR-ESI-MS)

    Data dictionary services in XNAT and the Human Connectome Project

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    The XNAT informatics platform is an open source data management tool used by biomedical imaging researchers around the world. An important feature of XNAT is its highly extensible architecture: users of XNAT can add new data types to the system to capture the imaging and phenotypic data generated in their studies. Until recently, XNAT has had limited capacity to broadcast the meaning of these data extensions to users, other XNAT installations, and other software.We have implemented a data dictionary service for XNAT, which is currently being used on ConnectomeDB, the Human Connectome Project (HCP) public data sharing website. The data dictionary service provides a framework to define key relationships between data elements and structures across the XNAT installation. This includes not just core data representing medical imaging data or subject or patient evaluations, but also taxonomical structures, security relationships, subject groups, and research protocols. The data dictionary allows users to define metadata for data structures and their properties, such as value types (e.g. textual, integers, floats) and valid value templates, ranges, or field lists. The service provides compatibility and integration with other research data management services by enabling easy migration of XNAT data to standards-based formats such as RDF, JSON, and XML. It also facilitates the conversion of XNAT’s native data schema into standard neuroimaging ontology structures and provenances.<br/

    Probability of detection of defects in coatings with electronic shearography

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    The goal of this research was to utilize statistical methods to evaluate the probability of detection (POD) of defects in coatings using electronic shearography. The coating system utilized in the POD studies was to be the paint system currently utilized on the external casings of the NASA Space Transportation System (STS) Revised Solid Rocket Motor (RSRM) boosters. The population of samples was to be large enough to determine the minimum defect size for 90 percent probability of detection of 95 percent confidence POD on these coatings. Also, the best methods to excite coatings on aerospace components to induce deformations for measurement by electronic shearography were to be determined

    Nanoscopy through a plasmonic nanolens.

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    Plasmonics now delivers sensors capable of detecting single molecules. The emission enhancements and nanometer-scale optical confinement achieved by these metallic nanostructures vastly increase spectroscopic sensitivity, enabling real-time tracking. However, the interaction of light with such nanostructures typically loses all information about the spatial location of molecules within a plasmonic hot spot. Here, we show that ultrathin plasmonic nanogaps support complete mode sets which strongly influence the far-field emission patterns of embedded emitters and allow the reconstruction of dipole positions with 1-nm precision. Emitters in different locations radiate spots, rings, and askew halo images, arising from interference of 2 radiating antenna modes differently coupling light out of the nanogap, highlighting the imaging potential of these plasmonic "crystal balls." Emitters at the center are now found to live indefinitely, because they radiate so rapidly.We acknowledge EPSRC grants EP/N016920/1, EP/L027151/1, and NanoDTC EP/L015978/1. OSO acknowledges support of Rubicon fellowship from the Netherlands Organisation for Scientific Research, and RC thanks support from Trinity College Cambridge
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