9,320 research outputs found

    Identifying the transporters of different flavonoids in plants

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    We recently identified a new component of flavonoid transport pathways in Arabidopsis. The MATE protein FFT (Flower Flavonoid Transporter) is primarily found in guard cells and seedling roots, and mutation of the transporter results in floral and growth phenotypes. The nature of FFT’s substrate requires further exploration but our data suggest that it is a kaempferol diglucoside. Here we discuss potential partner H+-ATPases and possible redundancy among the close homologues within the large Arabidopsis MATE family

    The P Cygni supergiant [OMN2000] LS1 – implications for the star formation history of W51

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    Original article can be found at: http://www.aanda.org/ Copyright The European Southern Observatory (ESO) DOI: 10.1051/0004-6361/200911980Aims. We investigate the nature of the massive star [OMN2000] LS1 and use these results to constrain the history of star formation within the host complex W51. Methods. We utilised a combination of near-IR spectroscopy and non-LTE model atmosphere analysis to derive the physical properties of [OMN2000] LS1 , and a combination of theoretical evolutionary calculations and Monte Carlo simulations to apply limits on the star formation history of W51. Results. We find the spectrum of [OMN2000] LS1 to be consistent with that of a P Cygni supergiant. With a temperature in the range of 13.2–13.7 kK and log( ) , it is significantly cooler, less luminous, and less massive than proposed by previous authors. The presence of such a star within W51 shows that star formation has been underway for at least 3 Myr, while the formation of massive O stars is still on going. The lack of a population of evolved red supergiants within the complex shows that the rate of formation of young massive clusters at ages 9 Myr was lower than currently observed. We find no evidence of internally triggered, sequential star formation within W51, and favour the suggestion that star formation has proceeded at multiple indepedent sites within the GMC. Along with other examples, such as the G305 and Carina star-forming regions, we suggest that W51 is a Galactic analogue of the ubiquitous star cluster complexes seen in external galaxies such as M51 and NGC2403.Peer reviewe

    Range safety signal propagation through the SRM exhaust plume of the space shuttle

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    Theoretical predictions of plume interference for the space shuttle range safety system by solid rocket booster exhaust plumes are reported. The signal propagation was calculated using a split operator technique based upon the Fresnel-Kirchoff integral, using fast Fourier transforms to evaluate the convolution and treating the plume as a series of absorbing and phase-changing screens. Talanov's lens transformation was applied to reduce aliasing problems caused by ray divergence

    Crime in Public Housing: Clarifying Research Issues

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    In recent years, crime and public housing have been closely linked in our political and popular cultures. Tragic episodes of violence have reinforced the notion that public housing is a milieu with rates of victimization and offending far greater than other locales. However, these recent developments belie the complex social and political evolution of public housing from its origins in the 1930s, through urban renewal, and into the present. Stereotypes abound about public housing, its management, residents, and crime rates. In reality, variation is the norm, and it is these variations that affect crime. The study of crime in public housing is in its earliest phase, and there is much to learn. A few studies suggest that crime rates are higher in public housing complexes than in their immediate surroundings; other studies suggest quite the opposite. Still others suggest a process of diffusion and exchange of violent crimes between public housing and the surrounding neighborhood contexts

    Reduced Myelin Water in the White Matter Tracts of Patients with Niemann-Pick Disease Type C

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    SUMMARY: Previous studies using diffusion tensor imaging to examine white matter in Niemann-Pick disease type C have produced mixed results. However, diffusion tensor imaging does not directly measure myelin and may be affected by other structural changes. We used myelin water imaging to more directly examine demyelination in 2 patients with Niemann-Pick disease type C. The results suggest that this technique may be useful for identifying regional changes in myelination in this condition

    Sports balls as potential SARS-CoV-2 transmission vectors.

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    Objects passed from one player to another have not been assessed for their ability to transmit severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We found that the surface of sport balls, notably a football, tennis ball, golf ball, and cricket ball could not harbour inactivated virus when it was swabbed onto the surface, even for 30 ​s. However, when high concentrations of 5000 ​dC/mL and 10,000 ​dC/mL are directly pipetted onto the balls, it could be detected after for short time periods. Sports objects can only harbour inactivated SARS-CoV-2 under specific, directly transferred conditions, but wiping with a dry tissue or moist 'baby wipe' or dropping and rolling the balls removes all detectable viral traces. This has helpful implications to sporting events

    Authority and the Future of Consent in Population-Level Biomedical Research

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    Population-level biomedical research has become crucial to the health system’s ability to improve the health ofthe population. This form of research raises a number of well-documented ethical concerns, perhaps the mostsignificant of which is the inability of the researcher to obtain fully informed specific consent from participants.Two proposed technical solutions to this problem of consent in large-scale biomedical research that havebecome increasingly popular are meta-consent and dynamic consent. We critically examine the ethical andpractical credentials of these proposals and find them lacking. We suggest that the consent problem is notsolved by adopting a technology driven approach grounded in a notion of ‘specific’ consent but by takingseriously the role of research governance in combination with broader conceptions of consent. In our view, theseapproaches misconstrue the rightful location of authority in the way in which population-level biomedicalresearch activities are structured and organized. We conclude by showing how and why the authority fordetermining the nature and shape of choice making about participation ought not to lie with individual participants, but rather with the researchers and the research governance process, and that this necessarily leads tothe endorsement of a fully articulated broad consent approach

    The supernova remnant CTB 37B and its associated magnetar CXOU J171405.7-381031: evidence for a magnetar-driven remnant

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    We discuss in this Letter the association of the candidate magnetar CXOU J171405.7-381031 with the supernova remnant CTB 37B. The recent detection of the period derivative of the object allowed an estimation of a young characteristic age of only 1000yr\sim 1000 yr. This value is too small to be compatible even with the minimum radius of the remnant 10pc\geq 10 pc, the value corresponding to the {\it lower} limit of the estimated distance of 10.2±3.5kpc10.2 \pm 3.5 kpc, unless the true distance happens to be even smaller than the lower limit. We argue that a consistent scenario for the remnant origin, in which the latter is powered by the energy injected by a young magnetar, is indeed more accurate to explain the young age, and points out to its non-standard (i.e. magnetar-driven) nature.Comment: 6 pp., 1 figure, to appear in RAA Letter

    New times, new politics: history and memory during the final years of the CPGB

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    This article examines the relationship between collective memory, historical interpretation and political identity. It focuses on the dissolution of the Communist Party of Great Britain (CPGB) as constructed through collective narrative memory, and on Marxist interpretations of history. The divisions within the party and the wider Marxist community, stretching from 1956 until 1991, were often framed around questions of historical interpretation. The events of 1989–1991 created an historical and mnemonic crisis for CPGB members who struggled to reconcile their past identities with their present situation. Unlike the outward-facing revisionism of other political parties, this was an intensely personal affair. The solution for many was to emphasise the need to find new ways to progress socialist aims, without relying on a discredited grand narrative. In contrast, other Communist parties, such as the Communist Party of Britain, which had been established (or ‘re-established’) in 1988, fared rather better. By adhering to the international party line of renewal and continued struggle, the party was able to hold its narrative together, condemning the excesses of totalitarian regimes, while reaffirming the need for international class struggle

    Effect of ion implantation on the oxygen overpotential of Ni anodes

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    This work investigates the use of ion implantation for decreasing the oxygen-overpotential of nickel anodes. It is part of a search for improved electrocatalysts to increase the energy efficiency of the H2O electrolysis process for producing H2 gas. A series of Ni electrodes were implanted at room temperature with various doses of 50 keV Ag+, Li+, He+, or Kr+ ions. Polarization measurements were then made in a suitable electrolysis cell over a wide range of current densities, using aqueous KOH solution (30%) at 80 °C as electrolyte. In the case of Ag+ implants, Rutherford backscattering (RBS) measurements were performed before and after electrolysis in order to monitor the amount and depth distribution of the Ag atoms. For Li+ or He+ implantation, we observe a negligible change in the measured polarization curves. For high dose Kr+ implants (I0^18 ions cm^(-2)) the Ni electrode exhibits an increase in overpotential, indicating that excessive damage and/or sputtering of the surface causes some deterioration in electrode behaviour. For Ag+ implants, on the other hand, we observe a large (20–40%) reduction in the total overpotential at implant doses of 0.3–4*10^16 Ag+ cm^(-2). Furthermore, RBS measurements show that prolonged electrolysis at higher current density (24–28 h at 1A/cm^(-2)) produces only a small loss of Ag and shifts its depth profile to significantly larger depths. Supplementary nuclear microanalyses, using the 16O(d, p )17O reaction, show that the shift in Ag profile is correlated with the growth of an anodic nickel oxide (+carbon) layer during electrolysis. In one set of runs, the Ni electrodes were thermally oxidized before Ag+ implantation in order to form an 400 Å layer of NiO at the surface. In this case, we observe a somewhat smaller reduction in overpotential following Ag+ implantation; furthermore, a large loss of Ag into the electrolyte occurs during the subsequent electrolysis
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