Coevolução de genética e sistemas de produção, para romper circulo vicioso no melhoramento vegetal.

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Occurrence of the orange wheat blossom midge [Diptera :Cecidomyiidae] in Quebec and its incidence on wheat grain microflora

À l'été 1995, on a prélevé des échantillons de blé (Triticum aestivum) dans des champs de diverses régions agricoles du Québec. La présence de larves de la cécidomyie orangée du blé (Sitodiplosis mosellana) fut quantifiée et une évaluation qualitative et quantitative de la microflore des grains fut réalisée. Les pertes moyennes de rendement causées par les larves de la cécidomyie du blé furent estimée à 6,3%. Le pourcentage des épis infestés fut significativement corrélé avec la contamination bactérienne et fongique des grains (r = 0,79). La présence spécifique du Fusarium graminearum dans les grains de blé fut aussi significativement corrélée avec le nombre de larves par épi (r= 0,67) ou par épillet (r= 0,67). Il appert que la cécidomyie du blé pourrait jouer un rôle dans la dissémination du F. graminearum.Samples of wheat spikes (Triticum aestivum) were collected in the summer of 1995 from different crop districts in Quebec and the occurrence of orange wheat blossom midge (Sitodiplosis mosellana) and seed microflora were determined. Estimated yield loss caused by wheat midge larvae averaged 6.3%. The percentage of infested spikes was significantly correlated with total seed contamination by fungi and bacteria (r = 0.79). The specific occurrence of Fusarium graminearum in grains was also significantly correlated with number of larvae per spike (r = 0.67) or per spikelet (r = 0.67). Consequently, the wheat midge might play a role in dissemination of F. graminearum

Exploring inter-organizational paradoxes: Methodological lessons from a study of a grand challenge

In this paper we outline a methodological framework for studying the inter-organizational aspects of paradoxes and specify this in relation to grand challenges. Grand challenges are large-scale, complex, enduring problems that affect large populations, have a strong social component, and appear intractable. Our methodological insights draw from our study of the insurance protection gap, a grand challenge that arises when economic losses from largescale disaster significantly exceed the insured loss, leading to economic and social hardship for the affected communities. We provide insights into collecting data to uncover the paradoxical elements inherent in grand challenges and then propose three analytical techniques for studying inter-organizational paradoxes: zooming in and out, tracking problematization, and tracking boundaries and boundary organizations. These techniques can be used to identify and follow how contradictions and interdependences emerge and dynamically persist within inter-organizational interactions and how these shape and are shaped by the unfolding dynamics of the grand challenge. Our techniques and associated research design help advance paradox theorizing by moving it to the inter-organizational and systemic level. This paper also illustrates paradox as a powerful lens through which to further our understanding of grand challenges

Extensive dissolution of live pteropods in the Southern Ocean

The carbonate chemistry of the surface ocean is rapidly changing with ocean acidification, a result of human activities. In the upper layers of the Southern Ocean, aragonite—a metastable form of calcium carbonate with rapid dissolution kinetics—may become undersaturated by 2050 (ref. 2). Aragonite undersaturation is likely to affect aragonite-shelled organisms, which can dominate surface water communities in polar regions. Here we present analyses of specimens of the pteropod Limacina helicina antarctica that were extracted live from the Southern Ocean early in 2008. We sampled from the top 200m of the water column, where aragonite saturation levels were around 1, as upwelled deep water is mixed with surface water containing anthropogenic CO2. Comparing the shell structure with samples from aragonite-supersaturated regions elsewhere under a scanning electron microscope, we found severe levels of shell dissolution in the undersaturated region alone. According to laboratory incubations of intact samples with a range of aragonite saturation levels, eight days of incubation in aragonite saturation levels of 0.94– 1.12 produces equivalent levels of dissolution. As deep-water upwelling and CO2 absorption by surface waters is likely to increase as a result of human activities2,4, we conclude that upper ocean regions where aragonite-shelled organisms are affected by dissolution are likely to expand

Black pitch, carved histories: radiocarbon dating, wood species identification and strontium isotope analysis of prehistoric wood carvings from Trinidad's Pitch Lake

We report on the results of a multi-disciplinary project (including wood identification, radiocarbon dating and strontium isotope analysis) focused on a collection of pre-Columbian wooden carvings and human remains from Pitch Lake, Trinidad. While the lake's unusual conditions are conducive to the survival of organic artefacts, they also present particular challenges for analysis. There is a loss of any contextual association beyond that of the lake, and specific methodologies are required to deal with pitch contamination. A surprising taxonomic range of woods was employed for the various utilitarian and ceremonial items recovered. The 14C results range from ca. 3200 BCE to ca. 700 CE, and include the earliest known wooden carvings in the entire Caribbean. The strontium isotope results - interpreted with the aid of an isoscape developed for the project, based on extensive samples of modern trees across Trinidad and Tobago - indicate that most carvings are consistent with the site's immediate environs; however, a ‘weaving tool’ came from a more radiogenic region that is unlikely to be found on Trinidad, suggesting links with the South American mainland

Technical note: An autonomous flow-through salinity and temperature perturbation mesocosm system for multi-stressor experiments

The rapid environmental changes in aquatic systems as a result of anthropogenic forcings are creating a multitude of challenging conditions for organisms and communities. The need to better understand the interaction of environmental stressors now, and in the future, is fundamental to determining the response of ecosystems to these perturbations. This work describes an automated ex situ mesocosm perturbation system that can manipulate several variables of aquatic media in a controlled setting. This perturbation system was deployed in Kongsfjorden (Svalbard); within this system, ambient water from the fjord was heated and mixed with freshwater in a multifactorial design to investigate the response of mixed-kelp communities in mesocosms to projected future Arctic conditions. The system employed an automated dynamic offset scenario in which a nominal temperature increase was programmed as a set value above real-time ambient conditions in order to simulate future warming. A freshening component was applied in a similar manner: a decrease in salinity was coupled to track the temperature offset based on a temperature–salinity relationship in the fjord. The system functioned as an automated mixing manifold that adjusted flow rates of warmed and chilled ambient seawater, with unmanipulated ambient seawater and freshwater delivered as a single source of mixed media to individual mesocosms. These conditions were maintained via continuously measured temperature and salinity in 12 mesocosms (1 control and 3 treatments, all in triplicate) for 54 d. System regulation was robust, as median deviations from nominal conditions were &lt; 0.15 for both temperature (∘C) and salinity across the three replicates per treatment. Regulation further improved during a second deployment that mimicked three marine heat wave scenarios in which a dynamic temperature regulation held median deviations to &lt; 0.036 ∘C from the nominal value for all treatment conditions and replicates. This perturbation system has the potential to be implemented across a wide range of conditions to test single or multi-stressor drivers (e.g., increased temperature, freshening, and high CO2) while maintaining natural variability. The automated and independent control for each experimental unit (if desired) provides a large breadth of versatility with respect to experimental design.</p