185 resultados para David, Gérard, approximately 1460-1523.
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We present a step-by-step guide of a refined magnetoseismological technique for plasma diagnostics in the Sun’s corona. Recently developed MHD wave theory which models a coronal loop as an expanding magnetic flux tube with an arbitrary longitudinal plasma density profile is applied to TRACE observations of fast kink
oscillations. The theory predicts that using the observed ratio of the first overtone and fundamental mode to predict the plasma density scale height and not taking account of loop expansion will lead to an overestimation of scale height. For the first time, the size of this correction is quantified directly from observation and for the particular case study presented here, it is found that the overestimation is approximately by a factor of 2.
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Malone, C.A.T. and S.K.F. Stoddart, Special Section. Introduction. David Clarke's 'Archaeology: the loss of Innocence' (1973) 25 years after.
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, Albion, 1993. 25(2): p. 318-9.
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This article reports on the development of an iPhone-based brain-exercise tool for seniors involving a series of focus groups (FGs) and field trials (FTs). Four FGs with 34 participants were conducted aimed at understanding the underlying motivational and de-motivational factors influencing seniors’ engagement with mobile brain-exercise software. As part of the FGs, participants had approximately 40 minutes hands-on experience with commercially available brain-exercise software. A content analysis was conducted on the data resulting in a ranking of 19 motivational factors, of which the top three were challenge, usefulness and familiarity and 15 de-motivational factors, of which the top-three were usability issues, poor communication and games that were too fast. Findings were used to inform the design of three prototype brain-exercise games for the iPhone contained within one overall application, named Brain jog. Subsequently, two FTs were conducted using Brain jog to investigate the part that time exposure has to play in shaping the factors influencing engagement. New factors arose with respect to the initial FGs including the motivational factor feedback and the de-motivational factor boring. The results of this research provide valuable guidelines for the design and evaluation of mobile brain-exercise software for seniors.
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Triose phosphate isomerase (TPI) catalyses the interconversion of dihydroxyacetone phosphate and glyceraldehyde 3-phosphate, a reaction in the glycolytic pathway. TPI from the common liver fluke, Fasciola hepatica, has been cloned, sequenced and recombinantly expressed in Escherichia coli. The protein has a monomeric molecular mass of approximately 28 kDa. Crosslinking and gel filtration experiments demonstrated that the enzyme exists predominantly as a dimer in solution. F. hepatica TPI is predicted to have a ß-barrel structure and key active site residues (Lys-14, His-95 and Glu-165) are conserved. The enzyme shows remarkable stability to both proteolytic degradation and thermal denaturation. The melting temperature, estimated by thermal scanning fluorimetry, was 67 °C and this temperature was increased in the presence of either dihydroxyacetone phosphate or glyceraldehyde 3-phosphate. Kinetic studies showed that F. hepatica TPI demonstrates Michaelis-Menten kinetics in both directions, with Km values for dihydroxyacetone phosphate and glyceraldehyde 3-phosphate of 2.3 mM and 0.66 mM respectively. Turnover numbers were estimated at 25,000 s(-1) for the conversion of dihydroxyacetone phosphate and 1900 s(-1) for the conversion of glyceraldehyde 3-phosphate. Phosphoenolpyruvate acts as a weak inhibitor of the enzyme. F. hepatica TPI has many features in common with mammalian TPI enzymes (e.g. ß-barrel structure, homodimeric nature, high stability and rapid kinetic turnover). Nevertheless, recent successful identification of specific inhibitors of TPI from other parasites, suggests that small differences in structure and biochemical properties could be exploited in the development of novel, species-specific inhibitors.
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We use natural seeing imaging of SN 2013ej in M74 to identify a progenitor candidate in archival Hubble Space Telescope (HST) + Advanced Camera for Survey images. We find a source coincident with the supernova (SN) in the F814W filter within the total 75 mas (~3 pc astrometric uncertainty; however, the position of the progenitor candidate in contemporaneous F435W and F555W filters is significantly offset. We conclude that the 'progenitor candidate' is in fact two physically unrelated sources; a blue source which is likely unrelated to the SN, and a red source which we suggest exploded as SN 2013ej. Deep images with the same instrument on board HST taken when the SN has faded (in approximately two year's time) will allow us to accurately characterize the unrelated neighbouring source and hence determine the intrinsic flux of the progenitor in three filters.We suggest that the F814W flux is dominated by the progenitor of SN 2013ej, and assuming a bolometric correction appropriate to an M-type supergiant, we estimate that the mass of the progenitor of SN 2013ej was between 8 and 15.5M⊙.
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During his forty-year curatorship of the Royal Dublin Society's botanical gardens in Glasnevin (1838–1879), David Moore undertook a number of excursions to continental Europe. These served to deepen the networks of plant exchange between Dublin and other botanical institutions and allowed him to examine the relationships between climate, plant survivability and societal development. This paper focuses on two trips taken in the 1860s to Scandinavia and Iberia and charts how Moore situated his experience of these places within a climatic hermeneutic. Moore's understanding of northern and southern Europe was organized around a set of judgments about their relative backwardness or advancement with respect to his experience of home and was seen through the lens of a moral climatology. Moreover, his Scots Presbyterian background and his commitment to natural theology informed his interpretation of the landscapes he encountered in his excursions across Europe.
Flow due to multiple jets downstream of a barrage: Experiments, 3-D CFD and depth-averaged modelling
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The flow through and downstream of a row of seven open draft tubes in a barrage has been investigated through laboratory experiments in a wide flume, a three-dimensional (3D) computational fluid dynamics simulation, and a two-dimensional depth-averaged computation. Agreement between the experiments and the 3D modeling is shown to be good, including the prediction of an asymmetric Coandă effect. One aim is to determine the distance downstream at which depth-averaged modeling provides a reasonable prediction; this is shown to be approximately 20 tube diameters downstream of the barrage. Upstream of this, the depth-averaged modeling inaccurately predicts water level, bed shear, and the 3D flow field. The 3D model shows that bed shear stress can be markedly magnified near the barrage, particularly where the jets become attached.
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Background: There is no method routinely used to predict response to anthracycline and cyclophosphamide–based chemotherapy in the clinic; therefore patients often receive treatment for breast cancer with no benefit. Loss of the Fanconi anemia/BRCA (FA/BRCA) DNA damage response (DDR) pathway occurs in approximately 25% of breast cancer patients through several mechanisms and results in sensitization to DNA-damaging agents. The aim of this study was to develop an assay to detect DDR-deficient tumors associated with loss of the FA/BRCA pathway, for the purpose of treatment selection.
Methods: DNA microarray data from 21 FA patients and 11 control subjects were analyzed to identify genetic processes associated with a deficiency in DDR. Unsupervised hierarchical clustering was then performed using 60 BRCA1/2 mutant and 47 sporadic tumor samples, and a molecular subgroup was identified that was defined by the molecular processes represented within FA patients. A 44-gene microarray-based assay (the DDR deficiency assay) was developed to prospectively identify this subgroup from formalin-fixed, paraffin-embedded samples. All statistical tests were two-sided.
Results: In a publicly available independent cohort of 203 patients, the assay predicted complete pathologic response vs residual disease after neoadjuvant DNA-damaging chemotherapy (5-fluorouracil, anthracycline, and cyclophosphamide) with an odds ratio of 3.96 (95% confidence interval [Cl] =1.67 to 9.41; P = .002). In a new independent cohort of 191 breast cancer patients treated with adjuvant 5-fluorouracil, epirubicin, and cyclophosphamide, a positive assay result predicted 5-year relapse-free survival with a hazard ratio of 0.37 (95% Cl = 0.15 to 0.88; P = .03) compared with the assay negative population.
Conclusions: A formalin-fixed, paraffin-embedded tissue-based assay has been developed and independently validated as a predictor of response and prognosis after anthracycline/cyclophosphamide–based chemotherapy in the neoadjuvant and adjuvant settings. These findings warrant further validation in a prospective clinical study.