2,157 research outputs found

    Design of an all-attitude flight control system to execute commanded bank angles and angles of attack

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    A flight control system for use in air-to-air combat simulation was designed. The input to the flight control system are commanded bank angle and angle of attack, the output are commands to the control surface actuators such that the commanded values will be achieved in near minimum time and sideslip is controlled to remain small. For the longitudinal direction, a conventional linear control system with gains scheduled as a function of dynamic pressure is employed. For the lateral direction, a novel control system, consisting of a linear portion for small bank angle errors and a bang-bang control system for large errors and error rates is employed

    Amyloid peptide ╬▓1-42 induces integrin ╬▒IIb╬▓3 activation, platelet adhesion and thrombus formation in a NADPH oxidase-dependent manner

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    This is the final version. Available on open access from Hindawi Publishing Corporation via the DOI in this recordThe progression of AlzheimerÔÇÖs dementia is associated with neurovasculature impairment, which includes inflammation, microthromboses, and reduced cerebral blood flow. Here, we investigate the effects of ╬▓ amyloid peptides on the function of platelets, the cells driving haemostasis. Amyloid peptide ╬▓1-42 (A╬▓1-42), A╬▓1-40, and A╬▓25-35 were tested in static adhesion experiments, and it was found that platelets preferentially adhere to A╬▓1-42 compared to other A╬▓ peptides. In addition, significant platelet spreading was observed over A╬▓1-42, while A╬▓1-40, A╬▓25-35, and the scA╬▓1-42 control did not seem to induce any platelet spreading, which suggested that only A╬▓1-42 activates platelet signalling in our experimental conditions. A╬▓1-42 also induced significant platelet adhesion and thrombus formation in whole blood under venous flow condition, while other A╬▓ peptides did not. The molecular mechanism of A╬▓1-42 was investigated by flow cytometry, which revealed that this peptide induces a significant activation of integrin ╬▒IIb╬▓3, but does not induce platelet degranulation (as measured by P-selectin membrane translocation). Finally, A╬▓1-42 treatment of human platelets led to detectable levels of protein kinase C (PKC) activation and tyrosine phosphorylation, which are hallmarks of platelet signalling. Interestingly, the NADPH oxidase (NOX) inhibitor VAS2870 completely abolished A╬▓1-42-dependent platelet adhesion in static conditions, thrombus formation in physiological flow conditions, integrin ╬▒IIb╬▓3 activation, and tyrosine- and PKC-dependent platelet signalling. In summary, this study highlights the importance of NOXs in the activation of platelets in response to amyloid peptide ╬▓1-42. The molecular mechanisms described in this manuscript may play an important role in the neurovascular impairment observed in AlzheimerÔÇÖs patients.Alzheimer┬┤s Research UKBritish Heart FoundationNational Institute for Health Research (NIHR

    Amyloid peptide ╬▓ 1-42 induces integrin ╬▒ IIb ╬▓ 3 activation, platelet adhesion, and thrombus formation in a NADPH Oxidase-Dependent Manner

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    The progression of Alzheimer's dementia is associated with neurovasculature impairment, which includes inflammation, microthromboses, and reduced cerebral blood flow. Here, we investigate the effects of ╬▓ amyloid peptides on the function of platelets, the cells driving haemostasis. Amyloid peptide ╬▓1-42 (A╬▓1-42), A╬▓1-40, and A╬▓25-35 were tested in static adhesion experiments, and it was found that platelets preferentially adhere to A╬▓1-42 compared to other A╬▓ peptides. In addition, significant platelet spreading was observed over A╬▓1-42, while A╬▓1-40, A╬▓25-35, and the scA╬▓1-42 control did not seem to induce any platelet spreading, which suggested that only A╬▓1-42 activates platelet signalling in our experimental conditions. A╬▓1-42 also induced significant platelet adhesion and thrombus formation in whole blood under venous flow condition, while other A╬▓ peptides did not. The molecular mechanism of A╬▓1-42 was investigated by flow cytometry, which revealed that this peptide induces a significant activation of integrin ╬▒IIb╬▓3, but does not induce platelet degranulation (as measured by P-selectin membrane translocation). Finally, A╬▓1-42 treatment of human platelets led to detectable levels of protein kinase C (PKC) activation and tyrosine phosphorylation, which are hallmarks of platelet signalling. Interestingly, the NADPH oxidase (NOX) inhibitor VAS2870 completely abolished A╬▓1-42-dependent platelet adhesion in static conditions, thrombus formation in physiological flow conditions, integrin ╬▒IIb╬▓3 activation, and tyrosine- and PKC-dependent platelet signalling. In summary, this study highlights the importance of NOXs in the activation of platelets in response to amyloid peptide ╬▓1-42. The molecular mechanisms described in this manuscript may play an important role in the neurovascular impairment observed in Alzheimer's patients

    Reviews

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    The following publications have been reviewed by the mentioned authors;Art and Society One. War by Ken Baynes, reviewed by Ronald FrankenbergArt and Society Two. Work by Ken Baynes and Alan Robinson, reviewed by Ronald FrankenbergArt and Society Three. Worship by Ken and Kate Baynes, reviewed by Ronald FrankenbergArt and Science by Dolf Rieser, reviewed by M. K. PaffardA COMMON SYSTEM OF EXAMINING AT 16+ by the Schols Council Examinations Bulletin No.23, reviewed by W. G. SkinnerSchool Resource Centres, the Schools Council Working Paper 43, reviewed by L. BroughA History of English Furniture by John Harrison, reviewed by S. J. EgglestonTrends in School Design by Eric Pearson, reviewed by P. K. BodenWorking Space, A Place to Paint, Language Aeas by Jason Dean, reviewed by P. K. BodenAlive to Art by Jose Llobera, reviewed by John LancasterVisual Education in the primary school by John M. Pickering, reviewed by L. BroughArt & Design Cards. Packs 1 & 2 by Ian Pillinger, reviewed by Francis ZankerWorkshop Assignments, Book One by S. Dunkerley & A. Huxton, reviewed by L. BroughStep By Step Metalwork, Book 3 by Kenneth Wells, reviewed by M. SayerIntroducing Jewellery Making by John Crawford, reviewed by John DecorteMaggie Hayes Jewellery Book by Maggie Hayes, reviewed by S. J. Egglesto

    Adatom Fe(III) on the hematite surface: Observation of a key reactive surface species

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    The reactivity of a mineral surface is determined by the variety and population of different types of surface sites (e.g., step, kink, adatom, and defect sites). The concept of "adsorbed nutrient" has been built into crystal growth theories, and many other studies of mineral surface reactivity appeal to ill-defined "active sites." Despite their theoretical importance, there has been little direct experimental or analytical investigation of the structure and properties of such species. Here, we use ex-situ and in-situ scanning tunneling microcopy (STM) combined with calculated images based on a resonant tunneling model to show that observed nonperiodic protrusions and depressions on the hematite (001) surface can be explained as Fe in an adsorbed or adatom state occupying sites different from those that result from simple termination of the bulk mineral. The number of such sites varies with sample preparation history, consistent with their removal from the surface in low pH solutions

    Quasars as standard candles III. Validation of a new sample for cosmological studies

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    We present a new catalogue of ~2,400 optically selected quasars with spectroscopic redshifts and X-ray observations from either Chandra or XMM-Newton. The sample can be used to investigate the non-linear relation between the UV and X-ray luminosity of quasars, and to build a Hubble diagram up to redshift z~7.5. We selected sources that are neither reddened by dust in the optical/UV nor obscured by gas in the X-rays, and whose X-ray fluxes are free from flux-limit related biases. After checking for any possible systematics, we confirm, in agreement with our previous works, that (i) the X-ray to UV relation provides distance estimates matching those from supernovae up to z~1.5, and (ii) its slope shows no redshift evolution up to z~5. We provide a full description of the methodology for testing cosmological models, further supporting a trend whereby the Hubble diagram of quasars is well reproduced by the standard flat ╬Ť\LambdaCDM model up to z~1.5-2, but strong deviations emerge at higher redshifts. Since we have minimized all non-negligible systematic effects, and proven the stability of the LXÔłĺLUVL_{\rm X}-L_{\rm UV} relation at high redshifts, we conclude that an evolution of the expansion rate of the Universe should be considered as a possible explanation for the observed deviation, rather than some systematic (redshift-dependent) effect associated with high-redshift quasars.Comment: 24 pages, 17 figures, accepted for publication in A&

    Quasars as standard candles: III. Validation of a new sample for cosmological studies

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    We present a new catalogue of 3c2400 optically selected quasars with spectroscopic redshifts and X-ray observations from either Chandra or XMM-Newton. The sample can be used to investigate the non-linear relation between the ultraviolet (UV) and X-ray luminosity of quasars as well as to build a Hubble diagram up to a redshift of z 3c 7.5. We selected sources that are neither reddened by dust in the optical and UV nor obscured by gas in the X-rays, and whose X-ray fluxes are free from flux-limit-related biases. After checking for any possible systematics, we confirm, in agreement with our previous works, that the X-ray to UV relation provides distance estimates matching those from supernovae up to z 3c 1.5, and its slope shows no redshift evolution up to z 3c 5. We provide a full description of the methodology for testing cosmological models, further supporting a trend whereby the Hubble diagram of quasars is well reproduced by the standard flat cold dark matter model up to z 3c 1.5-2, but strong deviations emerge at higher redshifts. Since we have minimised all non-negligible systematic effects and proven the stability of the LX - LUV relation at high redshifts, we conclude that an evolution of the expansion rate of the Universe should be considered as a possible explanation for the observed deviation, rather than some systematic (redshift-dependent) effect associated with high-redshift quasars

    Reviews

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    The following publications have been reviewed by the mentioned authors;Windsor Chairmaking by Thos Moser, reviewed by Bernard AylwardRelief Woodcarving by E. J. Tangerman, reviewed by Bernard AylwardWorking Green Wood with PEG by Patrick Spielman, reviewed by J. W. ThompsonWork Experience in Secondary Schools edited by John Eggleston, reviewed by Charles PeaceScale Model Cannon by Richard Stewart and Donald Heyes, reviewed by John EgglestonHow to Make Your Own Picture Frames by Hal Rogers and Ed Reinhardt, reviewed by John EgglestonThe Story of Craft by Edward Lucie Smith, reviewed by John EgglestonThe Landsdowne Book of Handcrafts reviewed by Roger BensonUnderstanding Design in the Home by Margaret Picton, reviewed by John EgglestonWoodturning Projects for Dining by John Sainsbury, reviewed by M. P. BourneCrafts Conference for Teachers - April 1982 published by Crafts Council, reviewed by Bernard L. MyersCraft Design Technology reviewed by M. JohnArt and Imaginations: A Study in the Philosophy of Mind by Roger Scruton, reviewed by G. H. Bantock'Forget all the rules you ever learned about Graphic Design including the ones in this Book by Bob Gill, reviewed by Cal SwannProfessional Smithing by Donald Streeter, reviewed by J. N. AtkinsGraphic Communication by John Twyford, reviewed by Cal Swan

    EFFECT OF SUGARCANE YELLOW LEAF VIRUS ON SUGARCANE YIELD AND JUICE QUALITY

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    Abstract In 1996, sugarcane plants infected with sugarcane yellow leaf virus (SCYLV), reported to cause yellow leaf syndrome (YLS), were discovered in Louisiana. Field experiments were established to assess the potential impact of the disease on the Louisiana sugarcane industry. In the first experiment, yield and juice quality of SCYLV-infected and non-infected plants of cultivar LCP82-89 were compared. Sugar yields per unit area were reduced 11 % and 14% in the first ratoon and second ratoon crops respectively. Stalk number and tonnage were reduced in SCYLV-infected plants. Cane quality components, % brix, % sucrose, % fibre and % purity, did not differ between infected and non-infected plants. However, % brix, % sucrose, and % purity were higher in juice from virus-infected green leaf tissue compared with healthy leaf tissue. In a second experiment, juice from leaves and stalks of infected and non-infected plants collected from plant cane, first ratoon, and second ratoon crops of cultivars LCP82-89 and LHo83-153 was analysed. Cane quality components did not differ in either cultivar. In juice from SCYLV-infected leaves, % sucrose was higher in LCP82-89 and % purity and starch concentrations were higher in both cultivars, while differences in total polysaccharides and oligosaccharides were not detected. Dextran content was inconsistent. The uppermost green leaves are normally removed from the stalk during mechanical harvesting; however, they may not be removed if the cane is lodged. Leaves delivered to the mill containing elevated levels of starch might reduce processing efficiency
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