749 research outputs found

    Reduced grapevine canopy size post-flowering via mechanical trimming alters ripening and yield of 'Pinot noir'

    Get PDF
    The degree and time of canopy trimming can alter phenology, rates of increase or decrease in berry components during grape ripening, and may influence yield and its components. The objective of this study was to investigate the extent to which reducing canopy size, by mechanical trimming post-flowering, changed Vitis vinifera L. 'Pinot noir' fruit yield and composition. Vines were mechanically trimmed to three different canopy heights at fruitset: 1000 mm (100 % canopy height), 600 mm (60 % canopy height relative to the control treatment) and 300 mm (30 % canopy height relative to the control treatment). Total soluble solids concentration and content, titratable acidity, pH and fresh berry mass were measured throughout ripening, and yield and leaf area were measured at harvest.Reduced canopy size via trimming to 30 and 60 % of the control treatment height slowed total soluble solids accumulation and in some cases increased titratable acidity and increased pH. The total soluble solids-titratable acidity ratio was therefore reduced throughout ripening by these trimming treatments relative to the full canopy height. Trimming to reduce canopy size had two effects on the source-sink ratio; it reduced the source (canopy) but increased fruit yield, an important sink. Therefore, the time of trimming is an important management consideration because it can delay and slow ripening due to reduced source leaves but could potentially accentuate the delay via increasing yield (sink). This technique may represent a way to offset the acceleration of phenology and grape ripening that has been observed to occur as a result of warmer seasons

    In situ XAFS Study of Palladium Electrodeposition at the Liquid/Liquid Interface

    Get PDF
    We report the use of XAFS (X-ray absorption fine structure) as an in situ method to follow the electrochemically driven deposition of palladium nanoparticles at a liquid/liquid interface. A novel glass/plastic hybrid electrochemical cell was used to enable control of the potential applied to the liquid/liquid interface. In situ measurements indicate that the nucleation of metallic nanoparticles can be triggered through chronoamperometry or cyclic voltammetry. In contrast to spontaneous nucleation at the liquid/liquid interface, whereby fluctuations in Pd oxidation state and concentration are observed, under a fixed interfacial potential the growth process occurs at a steady rate leading to a build-up of palladium at the interface. Raman spectroscopy of the deposit suggests that the organic electrolyte binds directly to the surface of the deposited nanoparticles. It was found that the introduction of citric acid results in the formation of spherical nanoparticles at the interface

    Forty years studying British politics : the decline of Anglo-America

    Get PDF
    The still present belief some 40 years ago that British politics was both exceptional and superior has been replaced by more theoretically sophisticated analyses based on a wider and more rigorously deployed range of research techniques, although historical analysis appropriately remains important. The American influence on the study of British politics has declined, but the European Union dimension has not been fully integrated. The study of interest groups has been in some respects a fading paradigm, but important questions related to democratic health have still to be addressed. Public administration has been supplanted by public policy, but economic policy remains under-studied. A key challenge for the future is the study of the management of expectations

    Functional and Biogenetical Heterogeneity of the Inner Membrane of Rat-Liver Mitochondria

    Get PDF
    Rat liver mitochondria were fragmented by a combined technique of swelling, shrinking, and sonication. Fragments of inner membrane were separated by density gradient centrifugation. They differed in several respects: electronmicroscopic appearance, phospholipid and cytochrome contents, electrophoretic behaviour of proteins and enzymatic activities. Three types of inner membrane fractions were isolated. The first type is characterized by a high activity of metal chelatase, low activities of succinate-cytochrome c reductase and of glycerolphosphate dehydrogenase, as well as by a high phospholipid content and low contents of cytochromes aa3 and b. The second type displays maximal activities of glycerolphosphate dehydrogenase and metal chelatase, but contains relatively little cytochromes and has low succinate-cytochrome c reductase activity. The third type exhibits highest succinate-cytochrome c reductase activity, a high metal chelatase activity and highest cytochrome contents. However, this fraction was low in both glycerolphosphate dehydrogenase activity and phospholipid content. This fraction was also richest in the following enzyme activities: cytochrome oxidase, oligomycin-sensitive ATPase, proline oxidase, 3-hydroxybutyrate dehydrogenase and rotenone-sensitive NADH-cytochrome c reductase. Amino acid incorporation in vitro and in vivo in the presence of cycloheximide occurs predominantly into inner membrane fractions from the second type. These data suggest that the inner membrane is composed of differently organized parts, and that polypeptides synthesized by mitochondrial ribosomes are integrated into specific parts of the inner membrane

    General Practitioners' views on the provision of nicotine replacement therapy and bupropion.

    Get PDF
    BACKGROUND: Nicotine replacement therapies (NRT) and a new drug, bupropion, are licensed in several countries as aids to smoking cessation. General practitioners (GPs) play a crucial role in recommending or prescribing these medications. In the UK there has been discussion about whether the medications should be reimbursable by the National Health Service (NHS). This study assessed English GPs' attitudes towards reimbursement of NRT and bupropion. METHODS: Postal survey of a randomly selected national sample of GPs; 376 GPs completed the questionnaire after one reminder; effective response rate: 53%. There was no difference between the responses of GPs who responded to the initial request and those who responded only after a reminder suggesting minimal bias due to non-response. RESULTS: Attitudes of GPs were remarkably divided on most issues relating to the medications. Forty-three percent thought that bupropion should not be on NHS prescription while 42% thought that it should be (15% did not know); Fifty percent thought that NRT should not be on NHS prescription while 42% thought it should be (8% did not know). Requiring that smokers attend behavioural support programmes to be eligible to receive the medications on NHS prescription made no appreciable difference to the GPs' views. GPs were similarly divided on whether having the medications reimbursable would add unacceptably to their workload or offer a welcome opportunity to discuss smoking with their patients. A principal components analysis of responses to the individual questions on NRT and bupropion revealed that GPs' attitudes could be understood in terms of a single 'pro-con' dimension accounting for 53% of the total variance which made no distinction between the two medications. CONCLUSIONS: GPs in England appear to be divided in their attitudes to medications to aid smoking cessation and appear not to discriminate in their views between different types of medication or different aspects of their use. This suggests that their attitudes are generated by quite fundamental values. Addressing these values may be important in encouraging GPs to adhere more closely to national and international guidelines

    The Hubble Constant from Observations of the Brightest Red Giant Stars in a Virgo-Cluster Galaxy

    Full text link
    The Virgo and Fornax clusters of galaxies play central roles in determining the Hubble constant H_0. A powerful and direct way of establishing distances for elliptical galaxies is to use the luminosities of the brightest red-giant stars (the TRGB luminosity, at M_I = -4.2). Here we report the direct observation of the TRGB stars in a dwarf elliptical galaxy in the Virgo cluster. We find its distance to be 15.7 +- 1.5 Megaparsecs, from which we estimate a Hubble constant of H_0 = 77 +- 8 km/s/Mpc. Under the assumption of a low-density Universe with the simplest cosmology, the age of the Universe is no more than 12-13 billion years.Comment: 12 pages, LaTeX, with 2 postscript figures; in press for Nature, July 199

    AnĂĄlise da imunogenicidade e da estabilidade do surfactante pulmonar de origem porcina administrado em coelhos

    Get PDF
    PURPOSE: To study the immunogenicity and the stability of the porcine pulmonary surfactant preparation produced by the Instituto Butantan. METHOD: Immunogenicity assay: Sixteen New-Zealand-White rabbits (1000 g body weight) were divided into 4 study groups. Each group was assigned to receive either a) Butantan surfactant, b) SurvantaÂź (Abbott Laboratories), c) CurosurfÂź (Farmalab Chiesi), or d) no surfactant. The surfactants were administered intratracheally, and the animals were collected immediately before and 60 and 180 days after surfactant administration. Sera were assayed for the presence of antisurfactant antibodies by enzyme-linked immunosorbent assay (ELISA). Stability assay: The Butantan surfactant used in this assay had been stored for one year in the refrigerator (4 to 8ÂșC) and its stability was evaluated in distinct assay conditions using a premature rabbit model. RESULTS: Immunogenicity assay: None of the surfactants analyzed triggered antibody immune responses against their components in any of the animals. Stability assay: The results of this study demonstrate that Butantan surfactant was as effective as Curosurf when both were submitted to the adverse circumstance of short- and long-term storage at room temperature. A similar level of efficacy for the Butantan surfactant, as compared to Curosurf was demonstrated by the pulmonary dynamic compliance, ventilatory pressure, and pressure-volume curve results. CONCLUSION: The results of our study demonstrate that Butantan surfactant may be a suitable alternative for surfactant replacement therapy.OBJETIVO: Estudar a imunogenicidade e a estabilidade do surfactante de origem porcina produzido pelo Instituto Butantan. MÉTODO: Experimento imunogenicidade: 16 coelhos da raça New-Zealand-White (Peso de 1000g) foram divididos em grupos de 4 animais. Cada grupo foi designado para receber: a) Surfactante do Butantan, b) SurvantaÂź (Abbott Laboratories), c) Curosurf (Farmalab Chiesi) e d) nenhum tratamento com surfactante. Os surfactantes foram administrados via intratraqueal e o sangue dos animais foi coletado antes, 60 e 180 dias apĂłs a administração do surfactante. O soro obtido foi analisado quanto a presença de anticorpos anti-surfactante pelo mĂ©todo ELISA (enzyme-linked immunosorbent assay). Experimento estabilidade: O surfactante do Butantan usado neste experimento tinha sido armazenado por um ano em refrigerador (4 a 8°C) e sua estabilidade foi analisada em condiçÔes distintas de experimentação, usando o modelo de coelho prematuro. RESULTADOS: Experimento imunogenicidade: Nenhum dos surfactantes analisados determinou a produção de anticorpos contra seus constituintes. Experimento estabilidade: Os resultados deste estudo demonstraram que o surfactante do Instituto Butantan mostrou eficĂĄcia semelhante a do Curosurf apĂłs ter sido submetido Ă  condiçÔes adversas ao longo do tempo. A eficĂĄcia foi demonstrada atravĂ©s da complacĂȘncia pulmonar dinĂąmica, pressĂŁo ventilatĂłria e da curva pressĂŁo-volume. CONCLUSÃO: Os resultados deste estudo demonstraram que o surfactante do Instituto Butantan pode representar um tratamento alternativo de reposição de surfactante

    In vivo STED microscopy visualizes morphological changes of large PSD95 assemblies over several hours in the mouse visual cortex

    Get PDF
    Abstract The post-synaptic density (PSD) is an electron dense region consisting of ~1000 proteins, found at the postsynaptic membrane of excitatory synapses, which varies in size depending upon synaptic strength. PSD95 is an abundant scaffolding protein in the PSD and assembles a family of supercomplexes comprised of neurotransmitter receptors, ion channels, as well as signalling and structural proteins. We use superresolution STED (STimulated Emission Depletion) nanoscopy to determine the size and shape of PSD95 in the anaesthetised mouse visual cortex. Adult knock-in mice expressing eGFP fused to the endogenous PSD95 protein were imaged at time points from 1 min to 6 h. Superresolved large assemblies of PSD95 show different sub-structures; most large assemblies were ring-like, some horse-shoe or figure-8 shaped, and shapes were continuous or made up of nanoclusters. The sub-structure appeared stable during the shorter (minute) time points, but after 1 h, more than 50% of the large assemblies showed a change in sub-structure. Overall, these data showed a sub-morphology of large PSD95 assemblies which undergo changes within the 6 hours of observation in the anaesthetised mouse
    • 

    corecore