1,025 research outputs found

    Determination of compressor in-stall characteristics from engine surge transients

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    A technique for extracting the in-stall pumping characteristics for an axial flow compressor operating in an engine system environment is developed. The technique utilizes a Hybrid computer simulation of the compressor momentum equation into which actual transient data are used to provide all terms but the desired compressor characteristic. The compressor force characteristic as a function of corrected flow and speed result from the computation. The critical problem of data filtering is addressed. Results for a compressor operating in a turbofan engine are presented and comparison is made with the conventional compressor map. The relationship of the compressor surge characteristic with its rotating stall characteristic is explored. Initial interpretation of the measured results is presented

    Quantification of the mycorrhizal fungal community associated with a modern wheat cultivar (Triticum aestivum) and with a wheat ancestor.

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    Abstract: Plant breeding is an important instrument to improve crop productivity. However, studies have shown that plant breeding, as well as the use of management practices such as tillage and fertilization, influence the plant root microbiome and also may have caused reduction in the genetic diversity of modern cultivars when compared to their ancestors. As the rhizosphere microbiome can profoundly impact plant growth, nutrition and health, we hypothesized that plant breeding can negatively affect the recruitment of beneficial microbes in the rhizosphere and interactions with their favorable microbial partners. A greenhouse experiment was conducted to assess the composition of the rhizosphere mycorrhizal fungi community in wheat (Triticum aestivum) varieties, modern cultivars and wheat ancestors. Plants were grown in forest and agricultural soils, collected in wheat cultivation area in SĂŁo Paulo, Brazil. The DNA was extracted from rhizospheric soil collected in the flowering stage, and the r RNA 18S gene copy number of mycorrhizal fungi was determined using quantitative real-time PCR (qPCR). The bulk soil presented less mycorrhizal fungi than rhizospheric soil of modern cultivars and more than rhizospheric soil of wheat ancestors indicating that these materials can be more selective in recruiting and structuring the rhizosphere microbiome. Modern cultivars were more intensely colonized by mycorrhizal fungi compared to ancestral genotypes and therefore possibly more dependent on these microorganisms. The results do not evidence that new crop plant genotypes lost their ability to respond to mycorrhizal due to agricultural and breeding practices, and further analyses needs to be performed

    Effect of phosphorus limitation on the microbial community assembly in the common bean (Phaseolus vulgaris L.) rhizosphere.

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    Abstract: The indiscriminate use of inputs in agricultural systems, particularly phosphate, combined with the need of growing food production, is causing the depletion of phosphorus mines around the world. In order to mitigate the environmental impact caused by phosphorus exploration microorganisms can be used to increase the efficiency of phosphorus utilization in crop systems by promoting nutrient solubilization and absorption. It is believed that low phosphorus concentration in soil, enriches specific members of the rhizosphere microbiome related to the availability of this element to the plant. In this study, a factorial experiment was performed considering contrasting cultivars in the uptake efficiency of phosphorus (being IAC-Imperador and DOR-364, the cultivar with high and low efficiency in P uptake); using soil with low P content and enriched concentrations of rock phosphate and single superphosphate. The rhizosphere microbiome was accessed using TSA and NBRIP media, to estimate total bacterial colony-forming units and identify isolates with potential of P solubilization, respectively. Total DNA was extracted and mycorrhizal fungi community was quantified using qPCR. The number of total bacteria colony-forming unit increased in the single superphosphate treatments of the IAC-Imperador (p<0.01), but not in DOR-364. Phosphorus solubilizing bacteria abundance also showed increase in single superphosphate treatments in both cultivars (p<0.01). Rock phosphate treatments did not showed any significant differences in colony-forming unit abundances. When considering the cultivar with higher efficiency in phosphorus uptake, the abundance of mycorrhizal fungi did not differed significantly. On the other hand, the lower efficient cultivar showed 5-fold increase with the addition of single superphosphate, and a 10-fold increase with rock phosphate (p<0.01). The results suggest that different type of P and the plant variety assembles the microbial community that helps plants in P uptake. The recruitment of mycorrhizal fungi is higher in the cultivar less efficient in phosphorus uptake, mainly when in the presence of phosphate rock

    Cloud Chamber: A Performance with Real Time Two-Way Interaction between Subatomic Particles and Violinist

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    ‘Cloud Chamber’ - a composition by Alexis Kirke, Antonino Chiaramonte, and Anna Troisi - is a live performance in which the invisible quantum world becomes visible as a violinist and subatomic particle tracks interact together. An electronic instrument was developed which can be “played” live by radioactive atomic particles. Electronic circuitry was developed enabling a violin to create a physical force field that directly affects the ions generated by cosmic radiation particles. This enabled the violinist and the ions to influence each other musically in real time. A glass cloud chamber was used onstage to make radioactivity visible in bright white tracks moving within, with the tracks projected onto a large screen

    Endpoint thermodynamics of an atomic Fermi gas subject to a Feshbach resonance

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    The entropy and kinetic, potential, and interaction energies of an atomic Fermi gas in a trap are studied under the assumption of thermal equilibrium for finite temperature. A Feshbach resonance can cause the fermions to pair into diatomic molecules. The entropy and energies of mixtures of such molecules with unpaired atoms are calculated, in relation to recent experiments on molecular Bose-Einstein condensates produced in this manner. It is shown that, starting with a Fermi gas of temperature T=0.1TF0T= 0.1 T_F^0, where TF0T_F^0 is the non-interacting Fermi temperature, an extremely cold degenerate Fermi gas of temperature Tâ‰Č0.01TF0T \lesssim 0.01 T_F^0 may be produced without further evaporative cooling. This requires adiabatic passage of the resonance, subsequent sudden removal of unpaired atoms, and adiabatic return. We also calculate the ratio of the interaction energy to the kinetic energy, a straightforward experimental signal which may be used to determine the temperature of the atoms and indicate condensation of the molecules.Comment: 12 pages, 5 figure

    Antinuclear antibodies (ANA) in chronic hepatitis C virus infection: correlates of positivity and clinical relevance.

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    We examined correlates of antinuclear antibody (ANA) positivity (ANA+) in individuals with chronic hepatitis C virus (HCV) infection and the effect of positivity on clinical outcome of HCV. Pretreatment sera from 645 patients from three centres in Sweden (n = 225), the UK (n = 207) and Italy (n = 213) were evaluated by indirect immunofluorescence on Hep-2 cells for ANA pattern and titre by a single laboratory. Liver biopsies were all scored by one pathologist. A total of 258 patients were subsequently treated with interferon monotherapy. There was a significant difference in the prevalence of ANA (1:40) by geographic location: Lund 4.4%, London 8.7%, Padova 10.3% [odds ratio (OR) = 0.66; 95% CI: 0.46-0.94; P = 0.023]. Duration of HCV infection, age at infection, current age, route of infection, viral genotype, alcohol consumption, fibrosis stage and inflammatory score were not correlated with ANA+ or ANA pattern. Female gender was correlated with ANA+ and this association persisted in multivariable analyses (OR = 3.0; P = 0.002). Increased plasma cells were observed in the liver biopsies of ANA-positive individuals compared with ANA-negative individuals, while a trend towards decreased lymphoid aggregates was observed [hazard ratio (HR) = 9.0, P = 0.037; HR = 0.291, P = 0.118, respectively]. No correlations were observed between ANA positivity and nonresponse to therapy (OR = 1.4; P = 0.513), although ANA+ was correlated with faster rates of liver fibrosis, this was not statistically significant (OR = 1.8; P = 0.1452). Low titre ANA+ should not be a contraindication for interferon treatment. Our observation of increased plasma cells in ANA+ biopsies might suggest B-cell polyclonal activity with a secondary clinical manifestation of increased serum immunoglobulins

    Enhanced Eshelby twist on thin wurtzite InP nanowires and measurement of local crystal rotation

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    We have performed a detailed study of the lattice distortions of InP wurtzite nanowires containing an axial screw dislocation. Eshelby predicted that this kind of system should show a crystal rotation due to the dislocation induced torque. We have measured the twisting rate and the dislocation Burgers vector on individual wires, revealing that nanowires with a 10-nm radius have a twist up to 100% larger than estimated from elasticity theory. The strain induced by the deformation has a Mexican-hat-like geometry, which may create a tube-like potential well for carriers

    A Systematic Review of Pharmacologic and Rehabilitative Treatment of Small Fiber Neuropathies

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    The aim of this systematic review is to guide the physician in defining the pharmacologicand rehabilitative therapeutic approaches for adopting the best strategies described in the currentliterature. The search was conducted in PubMed, EMBASE, Cochrane Library and Web of Scienceto identify the treatment of small fiber neuropathies. Two reviewers independently reviewed andcame to a consensus on which articles met inclusion/exclusion criteria. The authors excluded theduplicates, animal studies and included the English articles in which the treatment of patients withsmall fiber neuropathies was described. The search identified a total of 975 articles with the keywords“small fiber neuropathy” AND “rehabilitation” OR “therapy” OR “treatment”. Seventy-eight selectedfull-text were analyzed by the reviewers. Forty-two publications met the inclusion criteria and wereincluded in the systematic review to describe the rehabilitative and pharmacologic treatment of smallfiber neuropathies. Despite the range of different protocols of treatment for small fiber neuropathy,other robust trials are needed. In addition, always different therapeutic approaches are used; a uniqueprotocol could be important for the clinicians. More research is needed to build evidence for the beststrategy and to delineate a definitive therapeutic protocol
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