813 research outputs found

    Calcium sulfate ameliorates the effect of aluminum toxicity differentially in genotypes of highbush blueberry (Vaccinium corymbosum L.)

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    The effect of gypsum (CaSO 4) amendment in the reduction of Al phytotoxicity of blueberry cultivars differing in Al resistance (Legacy and Brigitta, Al-resistant and Bluegold, Al-sensitive) was studied in a Hoagland's nutrient solution under acidic conditions for 2 weeks. Treatments were: Control (Hoagland solution), 2.5 mM CaSO 4, 5 mM CaSO 4, 100 μM Al (AlCl 3), 100 μM Al + 2.5 μM CaSO 4, 100 M Al + 5 mM CaSO 4. Physiological, biochemical and chemical features of leaves and roots were determined to establish the amendment efficiency in the reduction of Al toxicity in these cultivars. Results showed that under Al toxicity the three investigated cultivars accumulated high Al concentrations in leaves and roots. These concentrations decreased with CaSO 4 application. Statistically significant interactions among Al in leaves but not in roots (p=0.719) and cultivars (p<0.001), were found. The lowest Ca concentration was found in the most Al-sensitive cultivar (Bluegold) and the highest in the more Al-resistant cultivars (Legacy and Brigitta). Among the underlying processes affected by Al stress in these blueberry cultivars the most evident changes were exhibited by the Al-sensitive cultivar Bluegold, where the photosynthetic performance decreased showing a slight recovery in presence of gypsum amendment at the end of experiment. Instead, the more Al-resistant cultivar (Legacy) did not change its photosynthetic parameters in presence of the gypsum amendments during the treatment, whereas in Brigitta, only a slight recovery at the end of treatment was evidenced by the gypsum application. Thus, in relation to these parameters the gypsum amendment was efficient in complete recovery from the toxic Al effect in the Al-resistant cultivar Brigitta and a slight recovery of the toxic Al effect in the Al-sensitive cultivar Bluegold. Nonetheless, this amendment is a good alternative to ameliorate Al toxicity in Al-sensitive cultivars and additionally provides a good source of Ca and S

    An institutional ethnography of prevention and treatment services for substance use disorders in the Dominican Republic

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    The Dominican Republic is thought to have significant epidemics of illicit drug use but lacks surveillance and formal analyses of the policy context of drug prevention and treatment services. We conducted an institutional ethnography of 15 drug service organisations in Santo Domingo and Boca Chica, Dominican Republic, to explore barriers and resources for drug abuse prevention and treatment. Here, we present a typology of drug service organisations based on their services, methods, and approach. We then draw on interviews with representatives of drug service institutions to describe the primary barriers to drug treatment and prevention services for drug users. We conclude with a focus on the policy priorities that could improve the conditions of health care for marginalised drug users in the Dominican Republic

    Efecto de aditivos lácteos en la fermentación y la estabilidad aeróbica en ensilajes de pasto kikuyo (Pennisetum clandestinum) y cáscara de naranja (Citrus sinensis).

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    AbstractThe conservation of forages through silage as a strategy to guarantee the availability of continuous feed during times of scarcity, is the best alternative for farmers regardless of the extent of their production. This study aimed to evaluate the effect of the inclusion of milk additives in fermentation, the organoleptic characteristics and aerobic stability in silages of kikuyo grass (Pennisetum clandestinum) and orange peel (Citrus sinensis), carried out in the city of Bogotá ( Colombia). Organoleptic characteristics, dry matter, pH, temperature at 5 fermentation times (day 0, day 5, day 10, day 15 and day 21) were evaluated. 3 treatments were evaluated with 3 repetitions each, whose base mass was 70% kikuyo grass and 30% orange peel. Treatment (T1) consisted of silage without inoculum as a control treatment; treatment (T2) silage added with kefir inoculum; and treatment (T3) silage added with commercial yogurt inoculum. In addition, post-opening aerobic stability was evaluated. It is concluded that the use of dairy additives favors the fermentation process of the silage, allowing rapid stabilization of this and preserving optimal quality characteristics even in the post-opening. Keywords: lactic fermentation, grass, fruits tree, lactobacillus.ResumenLa conservación de forrajes mediante el ensilaje como estrategia para garantizar la disponibilidad de alimento continuo durante épocas de escasez, es la mejor alternativa para los ganaderos sin importar la extensión de su producción. Este estudio tuvo como objetivo evaluar el efecto de la inclusión de aditivos lácteos en la fermentación, las características organolépticas y la estabilidad aeróbica en ensilajes de pasto kikuyo (Pennisetum clandestinum) y cáscara de naranja (Citrus sinensis), realizado en la ciudad de Bogotá (Colombia). Se evaluaron características organolépticas, materia seca, pH, temperatura a 5 tiempos de fermentación (día 0, día 5, día 10, día 15 y día 21). Se evaluaron 3 tratamientos con 3 repeticiones cada uno, cuya masa base fue 70% de pasto kikuyo y 30% de cáscara de naranja. El tratamiento (T1) consistió en ensilaje sin inóculo como tratamiento control; tratamiento (T2) ensilaje adicionado con inóculo de kéfir; y el tratamiento (T3) ensilaje adicionado con inóculo de yogurt comercial. Además, se evaluó estabilidad aeróbica posapertura. Se concluye que el uso de aditivos lácteos favorece el proceso fermentativo del ensilaje, permitiendo rápida estabilización de este y conservando características optimas de calidad incluso en la posapertura. Palabras clave: fermentación láctica, pasto, frutales, lactobacilos

    Adhesion mechanisms of Actinobacillus pleuropneumoniae to the porcine respiratory system and biofilm formation

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    Actinobacillus pleuropneumoniae is a Gram-negative bacterium and the causative agent of porcine pleuropneumonia, a highly contagious disease of pigs characterised by fibrinohaemorrhagic necrotising pneumonia. Although it has been well controlled in some developed countries, outbreaks can occur in pigs of all ages in contact with asymptomatic carriers, leading to significant economic losses to the swine industry due to the high morbidity and mortality rates. Adhesion is a critical step in the colonisation of the swine respiratory tract and the pathogenesis of the porcine pleuropneumonia; however, a literature review of this process is not available to date. Therefore, this review aims to provide information regarding the molecules that have been described in the adhesion of A. pleuropneumoniae to cells and tissues of the porcine respiratory tract. Since adhesion is the first step in biofilm formation, we included a section to describe the genes involved in this process; some of these genes could participate directly or indirectly in the adhesion of A. pleuropneumoniae to the porcine respiratory system. Although the role of biofilms in porcine pleuropneumonia is still not clear, these molecules could be considered in the future as candidates for vaccine development

    Native Chilean Fruits and the Effects of their Functional Compounds on Human Health

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    In recent years, there has been great interest in the nutraceutical compounds of fruits from native Chilean plant species. In this context, fruits of Amomyrtus meli (Meli), Aristotelia chilensis (Maqui), Berberis microphylla (Calafate), Luma apiculata (Arrayán), Luma chequén (Chequén), and Ugni molinae (Murtilla) growing predominantly in Chilean forests have been studied. This chapter has compiled the existing information about antioxidant activity and antioxidant compound contents of the above mentioned fruit species and their association with the prevention of pathophysiological disorders in humans, such as inflammation, diabetes, and cardiovascular diseases. Results show that the antioxidant compounds of these species, particularly anthocyanins, decrease inflammation as well as the risk of diabetes and cardiovascular diseases. Therefore, consumption of these fruits is a good alternative for preventing cardiovascular and age-related diseases and pathophysiological disorders

    Preliminary feasibility of near-infrared spectroscopy to authenticate grazing in dairy goats through milk and faeces analysis

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    Nowadays, society demands certification and authentication methodologies that are able to clarify the origin of different livestock products. This is considered of paramount importance in order to not only provide accurate information to consumers, but also to protect producers against fraudulent practices. In this context, the aim of this study is to establish a methodology to authenticate the grazing activity of dairy goats. To achieve this, milk and faeces samples were analysed using Near-Infrared Spectroscopy. The good results obtained in discriminant models demonstrated differences in both types of matrices when the two feeding regimes were compared. The development of this methodology could extend its use not only in dairy systems of goats but also in other animal species and systems

    Coseismic seafloor deformation in the trench region during the Mw8.8 Maule megathrust earthquake

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    The Mw 8.8 megathrust earthquake that occurred on 27 February 2010 offshore the Maule region of central Chile triggered a destructive tsunami. Whether the earthquake rupture extended to the shallow part of the plate boundary near the trench remains controversial. The up-dip limit of rupture during large subduction zone earthquakes has important implications for tsunami generation and for the rheological behavior of the sedimentary prism in accretionary margins. However, in general, the slip models derived from tsunami wave modeling and seismological data are poorly constrained by direct seafloor geodetic observations. We difference swath bathymetric data acquired across the trench in 2008, 2011 and 2012 and find ∼3-5 m of uplift of the seafloor landward of the deformation front, at the eastern edge of the trench. Modeling suggests this is compatible with slip extending seaward, at least, to within ∼6 km of the deformation front. After the Mw 9.0 Tohoku-oki earthquake, this result for the Maule earthquake represents only the second time that repeated bathymetric data has been used to detect the deformation following megathrust earthquakes, providing methodological guidelines for this relatively inexpensive way of obtaining seafloor geodetic data across subduction zone

    Process improvement proposal for the reduction of machine setup time in a copper transformation company using lean manufacturing tools

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    This study aimed to identify the causes of significant problems existing in the metallurgical sector, and a solution is proposed for the setup process. We detail the theoretical background of the processes in the lean manufacturing methodology, which will be applied to a rolling machine. Further, we provide a brief description of the company and the sector’s problems. We describe success stories of companies that implemented various lean manufacturing tools. We also present some of the results achieved across sectors to gain an in-depth understanding of the technique and a practical support of the implemented model. Our proposal is based on the lean manufacturing methodology; tools such as Single Minute Exchanges of Dies, Kaizen, 5S, and value stream mapping (VSM) will be used to reduce setup times and to impact machine layout and productivity positively. We also show the implementation results of a pilot plan conducted in the company over a period of more than 3 months.Revisión por pare

    Experimental and theoretical assessment of native oxide in the superconducting TaN

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    In this manuscript, we show through an experimental-computational proof of concept the native oxide formation into superconducting TaN films. First, TaN was synthesized at an ultra-high vacuum system by reactive pulsed laser deposition and characterized in situ by X-ray photoelectron spectroscopy. The material was also characterized ex situ by X-ray diffraction, transmission electron microscopy, and the four-point probe method. It was detected that TaN contained considerable oxygen impurities (up to 26 %O) even though it was grown in an ultra-high vacuum chamber. Furthermore, the impurified TaN evidence a face-centered cubic crystalline structure only and exhibits superconductivity at 2.99 K. To understand the feasibility of the native oxide in TaN, we study the effect of incorporating different amounts of O atoms in TaN using ab-initio calculations. A thermodynamic stability analysis shows that a TaOxN1-x model increases its stability as oxygen is added, demonstrating that oxygen may always be present in TaN, even when obtained at ultra-high vacuum conditions. All analyzed models exhibit metallic behavior. Charge density difference maps reveal that N and O atoms have a higher charge density redistribution than Ta atoms. The electron localization function maps and line profiles indicate that Ta-O and Ta-N bonds are mainly ionic. As expected, stronger ionic behavior is observed in the Ta-O bonds due to the electronegativity difference between O and N atoms. Recent evidence points to superconductivity in bulk TaO, confirming the asseverations of superconductivity in our samples. The results discussed here highlight the importance of considering native oxide when reporting superconductivity in TaN films since the TaO regions formed in the compound may be key to understanding the different critical temperatures reported in the literature.Comment: 23 pages, 7 figure
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