21,133 research outputs found

    The 50-horsepower solar-powered irrigation facility located near Gila Bend, Arizona

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    The 50 horsepower solar powered irrigation facility near Gila Bend, Arizona which includes a Rankine cycle demonstrates the technical feasibility of solar powered pumping. The design of a facility specifically for the irrigation farmer using the technology that has been developed over the last four years is proposed

    The application of remotely sensed data in support of emergency rehabilitation of wildfire-damage areas

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    The depth, texture, and water holding capacity of the soil before the fire in the Bridge Creek area of Deschutes National Forest (1979) were determined from available aerial photography and LANDSAT MSS digital data. Three days after the fire was out, complete coverage of the burned area was acquired on 35 mm color infrared film from a near vertical or low oblique perspective. These photographs were used in assessing the condition of vegetation, and in predicting the likelihood of survival. Negatives from vertical natural photography obtained during the same flight were used to produce 3R prints from which large scale mosaics of the entire burned area were obtained. LANDSAT MSS data obtained on the day the fire was under control were used to evaluate vegetative vigor (by calculating a band 7/band 5 ratio value for each spectral class) and to determine the boundary between altered and unaltered land

    Specific targeting of cytosine methylation to DNA sequences in vivo

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    Development of methods that will allow exogenous imposition of inheritable gene-specific methylation patterns has potential application in both therapeutics and in basic research. An ongoing approach is the use of targeted DNA methyltransferases, which consist of a fusion between gene-targeted zinc-finger proteins and prokaryotic DNA cytosine methyltransferases. These enzymes however have so far demonstrated significant and unacceptable levels of non-targeted methylation. We now report the development of second-generation targeted methyltransferase enzymes comprising enhanced zinc-finger arrays coupled to methyltransferase mutants that are functionally dominated by their zinc-finger component. Both in vitro plasmid methylation studies and a novel bacterial assay reveal a high degree of target-specific methylation by these enzymes. Furthermore, we demonstrate for the first time transient expression of targeted cytosine methyltransferase in mammalian cells resulting in the specific methylation of a chromosomal locus. Importantly, the resultant methylation pattern is inherited through successive cell divisions

    Post-aragonite phases of CaCO3_{3} at lower mantle pressures

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    The stability, structure and properties of carbonate minerals at lower mantle conditions has significant impact on our understanding of the global carbon cycle and the composition of the interior of the Earth. In recent years, there has been significant interest in the behavior of carbonates at lower mantle conditions, specifically in their carbon hybridization, which has relevance for the storage of carbon within the deep mantle. Using high-pressure synchrotron X-ray diffraction in a diamond anvil cell coupled with direct laser heating of CaCO3_{3} using a CO2_{2} laser, we identify a crystalline phase of the material above 40 GPa - corresponding to a lower mantle depth of around 1,000 km - which has first been predicted by \textit{ab initio} structure predictions. The observed sp2sp^{2} carbon hybridized species at 40 GPa is monoclinic with P21/cP2_{1}/c symmetry and is stable up to 50 GPa, above which it transforms into a structure which cannot be indexed by existing known phases. A combination of \textit{ab initio} random structure search (AIRSS) and quasi-harmonic approximation (QHA) calculations are used to re-explore the relative phase stabilities of the rich phase diagram of CaCO3_{3}. Nudged elastic band (NEB) calculations are used to investigate the reaction mechanisms between relevant crystal phases of CaCO3_{3} and we postulate that the mineral is capable of undergoing sp2sp^{2}-sp3sp^{3} hybridization change purely in the P21/cP2_{1}/c structure - forgoing the accepted post-aragonite PmmnPmmn structure.Comment: 12 pages, 8 figure

    Use of altered-specificity binding Oct-4 suggests an absence of pluripotent cell-specific cofactor usage

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    Oct-4 is a POU domain transcription factor that is critical for maintaining pluripotency and for stem cell renewal. Previous studies suggest that transcription regulation by Oct-4 at particular enhancers requires the input of a postulated E1A-like cofactor that is specific to pluripotent cells. However, such studies have been limited to the use of enhancer elements that bind other POU-protein family members in addition to Oct-4, thus preventing a ‘clean’ assessment of any Oct-4:cofactor relationships. Other attempts to study Oct-4 functionality in a more ‘stand-alone’ situation target Oct-4 transactivation domains to DNA using heterologous binding domains, a methodology which is known to generate artificial data. To circumvent these issues, an altered-specificity binding Oct-4 (Oct-4RR) and accompanying binding site, which binds Oct-4RR only, were generated. This strategy has previously been shown to maintain Oct-1:cofactor interactions that are highly binding-site and protein/binding conformation specific. This system therefore allows a stand-alone study of Oct-4 function in pluripotent versus differentiated cells, without interference from endogenous POU factors and with minimal deviation from bound wild-type protein characteristics. Subsequently, it was demonstrated that Oct-4RR and the highly transactive regions of its N-terminus determined here, and its C-terminus, have the same transactivation profile in pluripotent and differentiated cells, thus providing strong evidence against the existence of such a pluripotent cell-specific Oct-4 cofactor

    Leptogenesis from Pseudo-Scalar Driven Inflation

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    We examine recent claims for a considerable amount of leptogenesis, in some inflationary scenarios, through the gravitational anomaly in the lepton number current. We find that when the short distances contributions are properly included the amount of lepton number generated is actually much smaller.Comment: JHEP style, 11 pages. Corrected typ

    Shipping and the Spread of Infectious Salmon Anemia in Scottish Aquaculture

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    Long-distance transport of pathogens plays a critical role in the emergence of novel diseases. Shipping is a major contributor to such transport, and the role of ships in spreading disease has been recognized for centuries. However, statistical confirmation of pathogen spread by shipping is usually impractical. We present evidence of invasive spread of infectious salmon anemia in the salmon farms of Scotland and demonstrate a link between vessel visits and farm contamination. The link is associated with vessels moving fish between sites and transporting harvest, but not with vessels delivering food or involved in other work

    Technique for the Measurement of the In-Situ Development Rate

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    In the past, a Perkin Elmer Development Rate Monitor (DRM) has been used to measure the development rate of photoresist. However, due to several limitations of the DRM, the development rates measured therein, are not truly representative of the resist processing on a production lire. Subtleties in the development system are not obtained through the DRM and hence an in-situ development rate is required. Using a Site Services Development Spray Monitor (DSM 100) and a post processing algorithm. the in-situ measured development rates were obtained. The interference signals for eight different wavelengths were simultaneously monitored on a pattemed wafer as it spun on the development module of a wafer track. Since the interference signal is generated from a circularly polarized light source, the DSM 100 has demonstrated robustness to the red cloud effect, developer spray, bubbles in the developer, and ambient light.\u27 Two algorithms for the calculation of the in-situ development rate are proposed. After collecting the eight interference curves, these post processing algorithms used the Marquardt Levenberg non-linear regression algorithm and a linear regression approach to find the development rate as a function of development time. Although the standing wave effect was visible in the plots of development rate versus time using both techniques, the first approach generated the better curve. A plot of development rate versus depth was generated via numerical integration of the plot of development rate versus time. Since the only equation used in the post processing algorithm is the interference relationship, this technique is equally well suited for other types of exposure and resist chemistries. Possession of the in-situ development rate could provide further insight into resist development mechanisms, the development of better models, and the extraction of photolithography model parameters that are specific to the production process

    An improved ontological representation of dendritic cells as a paradigm for all cell types

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    The Cell Ontology (CL) is designed to provide a standardized representation of cell types for data annotation. Currently, the CL employs multiple is_a relations, defining cell types in terms of histological, functional, and lineage properties, and the majority of definitions are written with sufficient generality to hold across multiple species. This approach limits the CL’s utility for cross-species data integration. To address this problem, we developed a method for the ontological representation of cells and applied this method to develop a dendritic cell ontology (DC-CL). DC-CL subtypes are delineated on the basis of surface protein expression, systematically including both species-general and species-specific types and optimizing DC-CL for the analysis of flow cytometry data. This approach brings benefits in the form of increased accuracy, support for reasoning, and interoperability with other ontology resources. 104. Barry Smith, “Toward a Realistic Science of Environments”, Ecological Psychology, 2009, 21 (2), April-June, 121-130. Abstract: The perceptual psychologist J. J. Gibson embraces a radically externalistic view of mind and action. We have, for Gibson, not a Cartesian mind or soul, with its interior theater of contents and the consequent problem of explaining how this mind or soul and its psychological environment can succeed in grasping physical objects external to itself. Rather, we have a perceiving, acting organism, whose perceptions and actions are always already tuned to the parts and moments, the things and surfaces, of its external environment. We describe how on this basis Gibson sought to develop a realist science of environments which will be ‘consistent with physics, mechanics, optics, acoustics, and chemistry’
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