961 research outputs found

    Groundwater Heat Pump Equipment Selection Procedures for Architects, Designers, and Contractors

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    Engineers at the Utah Water Research Laboratory and the Mechanical Engineering Department at Utah State University have investigated the use of groundwater heat pumps for residential space heating and cooling in the Utah climate. They have found that this type of system conserves energy and may cost less for Utah home owners to operate than many conventional heating and cooling systems. Since the use of groundwater heat pumps will probably become more widespread in the near future, building and heating contractors should become more informed about what a groundwater heat pump is and how it works. The purpse of this publication is to answer some common questions about heat pumps and help the contractor feel more confident about working with this relatively new heating and cooling system

    Helical vs. fundamental solitons in optical fibers

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    We consider solitons in a nonlinear optical fiber with a single polarization in a region of parameters where it carries exactly two distinct modes, the fundamental one and the first-order helical mode. From the viewpoint of applications to dense-WDM communication systems, this opens way to double the number of channels carried by the fiber. Aside from that, experimental observation of helical (spinning) solitons and collisions between them and with fundamental solitons are issues of fundamental interest. We introduce a system of coupled nonlinear Schroedinger equations for fundamental and helical modes, which have nonstandard values of the cross-phase-modulation coupling constants, and investigate, analytically and numerically, results of "complete" and "incomplete" collisions between solitons carried by the two modes. We conclude that the collision-induced crosstalk is partly attenuated in comparison with the usual WDM system, which sometimes may be crucially important, preventing merger of the colliding solitons into a breather. The interaction between the two modes is found to be additionally strongly suppressed in comparison with that in the WDM system in the case when a dispersion-shifted or dispersion-compensated fiber is used.Comment: a plain latex file with the text and two ps files with figures. Physica Scripta, in pres

    Starter Solutions for Vegetable Transplants.

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    HO:LULF and HO:LULF Laser Materials

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    A laser host material LULF (LuLiF4) is doped with holmium (Ho) and thulium (Tm) to produce a new laser material that is capable of laser light production in the vicinity of 2 microns. The material provides an advantage in efficiency over conventional Ho lasers because the LULF host material allows for decreased threshold and upconversion over such hosts as YAG and YLF. The addition of Tm allows for pumping by commonly available GaAlAs laser diodes. For use with flashlamp pumping, erbium (Er) may be added as an additional dopant. For further upconversion reduction, the Tm can be eliminated and the Ho can be directly pumped

    Leveraging the power of place in citizen science for effective conservation decision making

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    Many citizen science projects are place-based - built on in-person participation and motivated by local conservation. When done thoughtfully, this approach to citizen science can transform humans and their environment. Despite such possibilities, many projects struggle to meet decision-maker needs, generate useful data to inform decisions, and improve social-ecological resilience. Here, we define leveraging the ‘power of place’ in citizen science, and posit that doing this improves conservation decision making, increases participation, and improves community resilience. First, we explore ‘place’ and identify five place dimensions: social-ecological, narrative and name-based, knowledge-based, emotional and affective, and performative. We then thematically analyze 134 case studies drawn from CitSci.org (n = 39), The Stewardship Network New England (TSN-NE; n = 39), and Earthwatch (n = 56) regarding: (1) use of place dimensions in materials (as one indication of leveraging the power of place), (2) intent for use of data in decision-making, and (3) evidence of such use. We find that 89% of projects intend for data to be used, 46% demonstrate no evidence of use, and 54% provide some evidence of use. Moreover, projects used in decision making leverage more (t = − 4.8, df = 117; p \u3c 0.001) place dimensions (= 3.0; s = 1.4) than those not used in decision making (= 1.8; s = 1.2). Further, a Principal Components Analysis identifies three related components (aesthetic, narrative and name-based, and social-ecological). Given these findings, we present a framework for leveraging place in citizen science projects and platforms, and recommend approaches to better impart intended outcomes. We discuss place in citizen science related to relevance, participation, resilience, and scalability and conclude that effective decision making as a means towards more resilient and sustainable communities can be strengthened by leveraging the power of place in citizen science

    Genome-wide screening for DNA variants associated with reading and language traits

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    This research was funded by: Max Planck Society, the University of St Andrews - Grant Number: 018696, US National Institutes of Health - Grant Number: P50 HD027802, Wellcome Trust - Grant Number: 090532/Z/09/Z, and Medical Research Council Hub Grant Grant Number: G0900747 91070Reading and language abilities are heritable traits that are likely to share some genetic influences with each other. To identify pleiotropic genetic variants affecting these traits, we first performed a genome‐wide association scan (GWAS) meta‐analysis using three richly characterized datasets comprising individuals with histories of reading or language problems, and their siblings. GWAS was performed in a total of 1862 participants using the first principal component computed from several quantitative measures of reading‐ and language‐related abilities, both before and after adjustment for performance IQ. We identified novel suggestive associations at the SNPs rs59197085 and rs5995177 (uncorrected P ≈ 10–7 for each SNP), located respectively at the CCDC136/FLNC and RBFOX2 genes. Each of these SNPs then showed evidence for effects across multiple reading and language traits in univariate association testing against the individual traits. FLNC encodes a structural protein involved in cytoskeleton remodelling, while RBFOX2 is an important regulator of alternative splicing in neurons. The CCDC136/FLNC locus showed association with a comparable reading/language measure in an independent sample of 6434 participants from the general population, although involving distinct alleles of the associated SNP. Our datasets will form an important part of on‐going international efforts to identify genes contributing to reading and language skills.Publisher PDFPeer reviewe

    Mutational analysis of human immunodeficiency virus type 1 protease suggests functional homology with aspartic proteinases.

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    Processing of the retroviral gag and pol gene products is mediated by a viral protease. Bacterial expression systems have been developed which permit genetic analysis of the human immunodeficiency virus type 1 protease as measured by cleavage of the pol protein precursor. Deletion analysis of the pol reading frame locates the sequences required to encode a protein with appropriate proteolytic activity near the left end of the pol reading frame but largely outside the gag-pol overlap region, which is at the extreme left end of pol. Most missense mutations within an 11-amino-acid domain highly conserved among retroviral proteases and with sequence similarity to the active site of aspartic proteinases abolish appropriate processing, suggesting that the retrovirus proteases share a catalytic mechanism with aspartic proteinases. Substitution of the amino acids flanking the scissile bond at three of the processing sites encoded by pol demonstrates distinct sequence requirements for cleavage at these different sites. The inclusion of a charged amino acid at the processing site blocks cleavage. A subset of these substitutions also inhibits processing at the nonmutated sites

    Groundwater Development in Arid Basins

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    Summary: Groundwater development frequently provides a means whereby tremendous new economic opportunities are opened up. If supplies are overdrawn (mined) the ensuing regional economy may be able to affort replacements from more costly sources. In the United States the Salt River Valley of Arizona and the valleys of California provide examples. Two cases are treated in this paper, Israel and West Pakistan. In Israel, besides furnishing more than half of the basic source of water suppply, groundwater development provides opportunity for both quantity and quality management, which makes possible use of surface supplies and reclaimed sewage as firm rather than marginal sources. This development will permit the total water resources of this small country, where agricultural production ranks among the world\u27s most efficient, to be utilized effectively down to almost the last drop by the mid 1970\u27s. Israel must then look to desalted water from the sea for further expansion of its overall water supply. In West Pakistan a combination of level terrain and leaky canals since about 1890 led to threatened waterlogging and salinity of more than 25 million acreas of irrigated land, even though supplies were less than half adequate for good productivity. By the 1950\u27s low yields and increasing population threatened starvation. However, initiation of groundwater development, first by the government and later by pricate entreprise, has, since 1960, let to construction of 3,500 governmental tube wells of about 3 cfs capacity and 30,000 private tube wells of slightly less than 1 cfs capacity. Results have been dramatic. Agricultural production and use of fertilizer are rapidly increasing, and opening of well development of pricate enterprise is providing the irrigator with benefits of free competition for his water custom which he did not previously enjoy. Ultimately, besides providing full supplies for an estimated 26 to 30 million acrea, drainage and salinity problems will be mitigated if about 50 million acre-feet are pumped each year from groundwater including about 28 million acre-feet to be mined from a reserve of about 1,900 million acre-feet. With some difficult surface storage development due to terrain, mining may eventually be reduced. Through an eventual technological solution for the continuing overdraft is not now in sight, perhaps an economy may be built which can affort such a solution when the time comes

    Bighorn Basin Coring Project (BBCP): a continental perspective on early Paleogene hyperthermals

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    During the summer of 2011, the Bighorn Basin Coring Project (BBCP) recovered over 900m of overlapping core from 3 different sites in late Paleocene to early Eocene fluvial deposits of northwestern Wyoming. BBCP cores are being used to develop high-resolution proxy records of the Paleocene–Eocene Thermal Maximum (PETM) and Eocene Thermal Maximum 2 (ETM2) hyperthermal events. These events are short-term, large magnitude global warming events associated with extreme perturbations to the earth’s carbon cycle. Although the PETM and ETM2 occurred ~55–52 million years ago, they are analogous in many ways to modern anthropogenic changes to the carbon cycle. By applying various sedimentological, geochemical, and palynological methods to the cores, we hope to better understand what caused these events, study the biogeochemical and ecological feedbacks that operated during them, and reveal precisely how they impacted continental environments. Core recovery was > 98% in all holes and most drilling was carried out without fluid additives, showing that continuous coring of continental smectitic deposits like these can be achieved with minimal risk of contamination to molecular biomarkers. Cores were processed in the Bremen Core Repository where the science team convened for 17 days to carry out data collection and sampling protocols similar to IODP projects. Initial results show that the weathered horizon extends to as much as ~30m below the surface and variations in magnetic susceptibility within the cores record an interplay between grain size and pedogenesis. Previous investigations of outcrops near the BBCP drill sites allow detailed evaluation of the effects of weathering on common proxy methods. Studies of lithofacies, organic geochemistry, stable isotope geochemistry, calibrated XRF core scanning, paleomagnetics, and palynology are underway and will represent the highest resolution and most integrated proxy records of the PETM from a continental setting yet known. An extensive outreach program is in place to capitalize on the educational value associated with the Bighorn Basin’s unusually complete record of Phanerozoic earth history

    Pandemic Drugs at Pandemic Speed: Infrastructure for Accelerating COVID-19 Drug Discovery with Hybrid Machine Learning- and Physics-based Simulations on High Performance Computers

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    The race to meet the challenges of the global pandemic has served as a reminder that the existing drug discovery process is expensive, inefficient and slow. There is a major bottleneck screening the vast number of potential small molecules to shortlist lead compounds for antiviral drug development. New opportunities to accelerate drug discovery lie at the interface between machine learning methods, in this case, developed for linear accelerators, and physics-based methods. The two in silico methods, each have their own advantages and limitations which, interestingly, complement each other. Here, we present an innovative infrastructural development that combines both approaches to accelerate drug discovery. The scale of the potential resulting workflow is such that it is dependent on supercomputing to achieve extremely high throughput. We have demonstrated the viability of this workflow for the study of inhibitors for four COVID-19 target proteins and our ability to perform the required large-scale calculations to identify lead antiviral compounds through repurposing on a variety of supercomputers
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