521 research outputs found

    Impact of light exposure on fruit composition of white 'Riesling' grape berries (Vitis vinifera L.)

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    Microclimate and irradiation have long been known to influence winegrape (Vitis vinifera) quality. However, microclimate influence on white grape quality has remained understudied, as most research efforts have focused on red varieties and their anthocyanin content. In this study, we investigated microclimatic effects on the phenolic and amino acid composition of white 'Riesling' grapes using bunch shading and leaf removal to manipulate grape microclimate. Both treatments were applied directly after fruit set (modified E‑L 27; (Coombe 1995)) as well as at the onset of veraison (E-L 34), and compared to a non-manipulated control. The concentration of malic acid, amino acids and total nitrogen were decreased by illumination during the berry growth, while content and concentration of phenolics were significantly increased by illumination. Strong negative correlations were observed between accumulation of amino acids and flavonols. Although accumulation of flavonols occurred throughout berry development, the most important phase of accumulation was post-veraison

    A modified HPLC method to detect salicylic acid in must and wine after its application in the field to induce fungus resistance

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    Since the application of salicylic acid (SA) to induce systemic acquired resistance (SAR) in plants is currently discussed as an alternative for copper against downy mildew (Plasmopara viticola), a sensitive HPLC method with UV/Vis-DAD-detection was developed to determinate SA in must and wine. The rate of recovery was 92 % at a level of 0.15 mg . l-1 with a detection limit of 0.003 mg . l-1. We have analyzed several musts and wines from field experiments with SA application and have compared their SA concentrations with 23 commercially available German wines. Nearly all samples contained small amounts of SA. The mean concentration in white and red wines was 0.05 mg . l-1 (0.11 mg . l-1 max.) and 0.16 mg . l-1 (0.43 mg . l-1 max.), respectively. Application of SA downy mildew control did not increase the amounts of SA in must or wine

    Our planet, our health, our future. Human health and the Rio conventions: biological diversity, climate change and desertification

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    Health is our most basic human right and one of the most important indicators of sustainable development. We rely on healthy ecosystems to support healthy communities and societies. Wellfunctioning ecosystems provide goods and services essential for human health. These include nutrition and food security, clean air and fresh water, medicines, cultural and spiritual values, and contributions to local livelihoods and economic development. They can also help to limit disease and stabilize the climate. Health policies need to recognize these essential contributions. The three so-called Rio Conventions arising from the 1992 Earth Summit – the Convention on Biological Diversity, the United Nations Framework Convention on Climate Change and the United Nations Convention to Combat Desertification – together aim to maintain well-functioning ecosystems for the benefit of humanity. There is growing evidence of the impacts of global environmental changes on ecosystems and people, and a renewed consciousness among peoples and nations of the need to act quickly to protect the planet’s ecological and climatic systems. In the last two decades, the Rio Conventions have brought global attention to the impacts of anthropogenic change on the ecosystems of the planet. Increasingly unsustainable practices are placing pressure on natural resources to meet the demands of our economies and the needs of a rapidly growing global population, resulting in soil, water and air pollution, increased emissions of greenhouse gases, deforestation and land use change, expanded urban areas, introduction of non-native species, and inadequately planned development of water and land resources to meet food and energy needs. These changes are having both direct and indirect impacts on our climate, ecosystems and biological diversity. More than ever, the pursuit of public health, at all levels from local to global, now depends on careful attention to the processes of global environmental change. Traditional knowledge and scientific evidence both point to the inexorable role of global environmental changes in terms of their impact on human health and well-being. In many countries, anthropogenic changes to agriculture-related ecosystems have resulted in great benefits for human health and well-being, in particular through increased global food production and improved food security. These positive impacts, however, have not benefited everyone, and unsustainable levels of use of ecosystems have resulted in irreparable loss and degradation, with negative consequences for health and well-being. These range from emerging infectious diseases to malnutrition, and contribute to the rapid rise in noncommunicable diseases. Large-scale human transformation of the environment has contributed to increased disease burdens associated with the expansion of ecological and climatic conditions favourable for disease vectors. For all humans, the provision of adequate nutrition, clean water, and long-term food security depend directly on functioning agro-ecosystems and indirectly on the regulating ecosystem services of the biosphere; these ecosystem services can be eroded if overexploited and poorly managed

    Application of yeast with reduced alcohol yield for sparkling wine production

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    Two commercial yeast strains with reduced alcohol production in comparison with a commercial yeast strain with common alcohol yield were assed for their suitability in sparkling wine production according to the traditional bottle fermentation. The different yeast strains were applied for the first fermentation. As expected the base wine differed in terms alcohol. Furthermore the yeast with lower alcohol content showed higher values of glycerol, higher arginine content and in the same time reduced levels of proline after fermentation. However those samples showed increased volatile acidity values, compared to the control wines. The later bottle fermentation with a uniform yeast strain showed similar fermentation kinetics for all four lots. Sensory evaluation showed no clear differences between the sparkling wines that were stored 9 months on the lees. The base wines nevertheless clearly differed from each other. Besides the increased production of volatile acidity, the tested yeast strains with lower alcohol production appear very promising for the sparkling wine industry to face the generally rising alcohol contents worldwide

    Treatment outcomes among HIV-positive orphaned and non-orphaned children on antiretroviral therapy in Johannesburg, South Africa

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    Background. Limited research investigating treatment outcomes for HIV-positive orphans compared with non-orphans has shown mixed results, with several studies indicating that HIV-positive orphans are at greater risk of delayed access to HIV care and poor antiretroviral therapy (ART) adherence, while other data suggest that ART outcomes of orphans can be similar to those of non-orphans. Understanding the impact of orphan status on short-term ART outcomes could improve targeted intervention strategies, and subsequent long-term treatment and developmental outcomes, for HIV-positive infants, children and adolescents.Objectives. To evaluate the relationship between orphan status and ART outcomes among HIV-positive infants, children and adolescents initiating ART at two large public sector HIV clinics in Johannesburg, South Africa.Methods. This was a retrospective cohort study of HIV-positive children aged <18 years initiating standard first-line ART between June 2004 and May 2013. Using propensity scores, orphans and non-orphans were matched for age, sex, World Health Organization stage and ART regimen. The effect of orphanhood on attrition from care (all-cause mortality and loss to follow-up) was evaluated using Cox proportional hazards regression analysis, and its effect on having a detectable viral load (≄400 copies/mL) at 12 months on ART using binomial regression analysis with modified Poisson distribution.Results. A total of 251 (29.4%) orphans (maternal, paternal or both) and 603 (70.6%) non-orphans were included at ART initiation. Following multiple imputation for missing data and propensity score matching, 222 orphans and 222 non-orphans were included. Orphans had a median age of 8.0 years (interquartile range (IQR) 4.9 - 10.7) and non-orphans 7.4 years (IQR 4.2 - 10.2). A total of 12 (5.4%) orphans and 33 (14.9%) non-orphans experienced attrition from care during the first 12 months on ART (adjusted hazard ratio 0.32, 95% confidence interval (CI) 0.17 - 0.63). Among those alive and in care, with a viral load at 12 months on ART, 18.0% of orphans (33/183) and 14.8% of non-orphans (24/162) had a detectable viral load (adjusted risk ratio 1.15, 95% CI 1.04 - 1.28).Conclusions. Orphans were less likely than non-orphans to experience attrition, but among those in care at 12 months, orphans were more likely to have detectable viral loads. Lower attrition among orphans may be due to their being in institutional or foster care, ensuring that they make their visits; however, their higher rates of non-suppression may result from lack of psychosocial support or stigma resulting in struggles to adhere. Additional research investigating age-specific outcomes will be important to elucidate these effects further

    Riemann solvers and undercompressive shocks of convex FPU chains

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    We consider FPU-type atomic chains with general convex potentials. The naive continuum limit in the hyperbolic space-time scaling is the p-system of mass and momentum conservation. We systematically compare Riemann solutions to the p-system with numerical solutions to discrete Riemann problems in FPU chains, and argue that the latter can be described by modified p-system Riemann solvers. We allow the flux to have a turning point, and observe a third type of elementary wave (conservative shocks) in the atomistic simulations. These waves are heteroclinic travelling waves and correspond to non-classical, undercompressive shocks of the p-system. We analyse such shocks for fluxes with one or more turning points. Depending on the convexity properties of the flux we propose FPU-Riemann solvers. Our numerical simulations confirm that Lax-shocks are replaced by so called dispersive shocks. For convex-concave flux we provide numerical evidence that convex FPU chains follow the p-system in generating conservative shocks that are supersonic. For concave-convex flux, however, the conservative shocks of the p-system are subsonic and do not appear in FPU-Riemann solutions

    Hyperpolarized Long-T1 Silicon Nanoparticles for Magnetic Resonance Imaging

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    Silicon nanoparticles are experimentally investigated as a potential hyperpolarized, targetable MRI imaging agent. Nuclear T_1 times at room temperature for a variety of Si nanoparticles are found to be remarkably long (10^2 to 10^4 s) - roughly consistent with predictions of a core-shell diffusion model - allowing them to be transported, administered and imaged on practical time scales without significant loss of polarization. We also report surface functionalization of Si nanoparticles, comparable to approaches used in other biologically targeted nanoparticle systems.Comment: supporting material here: http://marcuslab.harvard.edu/Aptekar_hyper1_sup.pd

    Ecology: a prerequisite for malaria elimination and eradication

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    * Existing front-line vector control measures, such as insecticide-treated nets and residual sprays, cannot break the transmission cycle of Plasmodium falciparum in the most intensely endemic parts of Africa and the Pacific * The goal of malaria eradication will require urgent strategic investment into understanding the ecology and evolution of the mosquito vectors that transmit malaria * Priority areas will include understanding aspects of the mosquito life cycle beyond the blood feeding processes which directly mediate malaria transmission * Global commitment to malaria eradication necessitates a corresponding long-term commitment to vector ecolog

    Analytical methods in wineries: is it time to change?

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    A review of the methods for the most common parameters determined in wine—namely, ethanol, sulfur dioxide, reducing sugars, polyphenols, organic acids, total and volatile acidity, iron, soluble solids, pH, and color—reported in the last 10 years is presented here. The definition of the given parameter, official and usual methods in wineries appear at the beginning of each section, followed by the methods reported in the last decade divided into discontinuous and continuous methods, the latter also are grouped in nonchromatographic and chromatographic methods because of the typical characteristics of each subgroup. A critical comparison between continuous and discontinuous methods for the given parameter ends each section. Tables summarizing the features of the methods and a conclusions section may help users to select the most appropriate method and also to know the state-of-the-art of analytical methods in this area
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