1,778 research outputs found

    A study of the relationship between seed quality and commercial sprouting quality of green gram (Vigna mungo L. Hepper) and black gram (Vigna radiata L. Wilczek) : a thesis presented in partial fulfilment of the requirement for the degree of Master of Applied Science in Seed Technology at Massey University, Palmerston North, New Zealand

    Get PDF
    Page 68 is missing from the original copy.Standard seed quality tests (seed moisture content, thousand seed weight, topographical tetrazolium, germination and seedling evaluation); vigour tests (accelerated ageing, conductivity, rate of germination and uniformity of germination) and industry based tests (oversoaks and sprouters) were evaluated for their ability to rank eight black gram (Vigna mungo L. Hepper) seed lots and seven green gram (Vigna radiata L. Wilczek) seed lots for the purpose of commercial sprouting. Each seed lot was sprouted using simulated commercial conditions (19°C water temperature; 20°C cabin temperature; dark; 5 days). Seed lots which performed well under these small scale commercial production (SSCP) conditions, in terms of total fresh yield and healthy sprout yield, were considered to be the best quality seed lots. All tests were able to significantly determine differences among seed lots within each species. Linear regression analysis indicated that interim germination (R² = 79.1%), final germination (R² = 76.3%), seed moisture content (SMC) (R² = 63.7%) and oversoak sprouters (R² = 60.6%) were significantly related to total fresh yield in green gram seed lots only. No other significant linear relationships were found for either green gram or black gram. Incorporating interim germination, final germination, SMC and oversoak sprouters in a multivariate analysis reduced the level of unexplained variation in green gram total sprout yield. The best combination was interim germination and oversoak sprouters (R² = 84.2%); Y = 9.1(%interim germination) - 8.1 (oversoak %sprouters) + 731.4. Very similar to this was the combination of final germination and SMC (R² = 83.8%); Y = 4.7(%final germination) + 15.3(%SMC) + 165.4. The reason for the differing responses of black gram and green gram was not explained, but both genetic variation and differences in environment during seed development and handling prior to testing are likely causes. It was not possible to use any individual or combination of tests to predict sprouting performance for green or black gram with the accuracy the sprouting industry would require. However, the results have shown that it will be possible to eliminate many of the seed quality tests examined from further research. Refinement of test procedures for the relevant standard and industry based tests will be required to provide the accurate seed testing regime needed by the sprouting industry

    Colusión sin evidencia directa en el Perú ¿la sospecha basta?

    Get PDF
    In the largest antitrust case prosecuted in Peru during the 2000s, the competition authority fined three firms for colluding to supply oxygen to Social Security hospitals (ESSALUD). At first the case looked simple: between 1999 and 2002 these firms won tenders in the same geographical areas in processes where the other two bidders always disqualified themselves. Moreover, this is an industry with a history of anticompetitive practices, since producers of industrial and medical gases have been found guilty of collusion in several countries, including Brazil, Argentina, Chile and the European Union. However, a deeper look at the economic evidence of the case shows that it was not conclusive, since the collusion hypothesis cannot explain key facts: the reason for which the firms disqualified themselves, since the others did not require it to win the tenders; the reason why the firms would maintain a collusive agreement that could not provide higher benefits than competition; and the price evidence that shows ESSALUD was exerting market power at the same time it was the supposed victim of a collusion. Likewise, the collusion hypothesis implies that the behavior of the firms was irrational, since i) a producer representing 85% of the market colluded with two firms representing 10% and 5%, ii) to allow them to gain market share at its expense, iii) to sell the product at increasingly lower prices than those paid by the rest of buyers, iv) through contracts obtained bidding the lowest possible price. This paper argues the collusion could not be proven and thus, the case should have been dropped

    ¿Puerto o playa? Un análisis económico del conflicto entre la ciudad de Trujillo y el puerto de Salaverry

    Get PDF
    Salaverry es un pequeño puerto localizado a pocos kilómetros de la ciudad de Trujillo, al norte del Perú. Moviliza alrededor de 2.5 millones de toneladas de carga al año, en su mayoría, granel seco. Desde 1982, ENAPU, la empresa estatal que opera el puerto, ha venido reduciendo sus costos de dragado mediante el alargamiento de un molón retenedor de arena, solución que ha alterado el equilibrio dinámico de la costa y causado la virtual desaparición de las playas de Trujillo. Desde el punto de vista de las políticas públicas, el problema se vuelve aún más complejo si se toma en cuenta el alto costo de las obras necesarias para detener la erosión de las playas (US150millones),elincrementodelademandapormaˊsymejoresserviciosambientales,ylopocoprobablequeresultaconcesionaralsectorprivadounaoperacioˊnquegeneraunaexternalidadnegativatanseria.ElobjetivodeesteestudioeseldeexaminarelconflictoentreelpuertodeSalaverryylaciudaddeTrujillodesdeelpuntodevistaeconoˊmico,ydeterminarcuaˊlessusolucioˊnmaˊseficientemedianteanaˊlisisdeterminıˊsticosyprobabilıˊsticosdesdelospuntosdevistapuˊblicoyprivado.Losresultadosindicanque:(i)elterminalportuariodeSalaverrynogenerarecursossuficientesparaoperarsinunsubsidio,menosauˊnparapagarelcostodelareparacioˊnambiental;(ii)paraconcesionarelterminalalsectorprivado,elgobiernodeberaˊotorgarunsubsidiocercanoalosUS 150 millones), el incremento de la demanda por más y mejores servicios ambientales, y lo poco probable que resulta concesionar al sector privado una operación que genera una externalidad negativa tan seria. El objetivo de este estudio es el de examinar el conflicto entre el puerto de Salaverry y la ciudad de Trujillo desde el punto de vista económico, y determinar cuál es su solución más eficiente mediante análisis determinísticos y probabilísticos desde los puntos de vista público y privado. Los resultados indican que: (i) el terminal portuario de Salaverry no genera recursos suficientes para operar sin un subsidio, menos aún para pagar el costo de la reparación ambiental; (ii) para concesionar el terminal al sector privado, el gobierno deberá otorgar un subsidio cercano a los US 25 millones; y, (iii) cerrar el puerto no es recomendable, pues si bien mantenerlo operativo le costaría a la sociedad US175millones,cerrarlolegenerarıˊacostosporUS 175 millones, cerrarlo le generaría costos por US 322 millones

    Good regulations, bad regulation: a Peruvian port case

    Get PDF
    Lead poisoning of Callao’s population is the most severe externality port operations cause in Peru. The problem could have been tackled in 2009, after the government issued a decree regulating how mineral ore was to be handled at Peruvian ports. However, the port regulator’s inability to follow the criteria contained in their own regulations led the procedure of selecting the providers of the service to continuous delays, and finally, to a complete stop. As a consequence, Callao’s population will continue to be affected by this externality until 2013. The problem the regulator could not solve was to determine whether the market for ‘mineral ore stevedore services’ at Callao Port was monopolistic or competitive. This article re-examines the case and concludes that the market for the service has natural monopoly characteristics. Therefore, the regulator should have ordered the call of an auction to select the least-expensive provider and thus, spare the population from four more years of lead poisoning

    Application d'une méthode de Galerkin multiharmonique au calcul des densités spectrales de puissance évolutives

    No full text
    Les systèmes mécaniques sous entrée aléatoire peuvent posséder, dans le cas de sollicitations sismiques par exemple, des réponses telles que l'amplitude mais aussi le contenu fréquentiel sont modulés dans le temps et conduisent à des DSP évolutives. La réponse instationnaire est approchée, sur un intervalle de temps T, par un développement de Galerkin, en sinus et cosinus, à un ordre fini M dont les coefficients sont lentement variables en fonction du temps et conduisent à une DSP évolutive. Les équations déterminantes, algébriques dans le cas stationnaire, sont remplacées par des équations différentielles dont les coefficients et le terme forçant dépendent uniquement du temps lent. Le calcul de l'accélération pour un modèle d'excitation sismique est donné comme exemple de résulta

    Supported nickel nitride catalysts for the gas-phase hydrogenation of furfural

    Get PDF
    A series of catalysts with different nickel loading (2.5-30 wt%) has been prepared by UGR. The preparation of Ni3N phase was ascertained via Powder X-rays diffraction together with cubic nickel . The elemental chemical analysis and XPS data confirm the presence of the nitride phase. Their catalytic performance points out that catalysts with loading of 5-10 wt% Ni exhibit a higher stability, maintaining furfural conversion values higher than 75% after 5 h of time-on-stream at 170ºC, and the main products detected were furfuryl alcohol (hydrogenation) and furan (decarbonylation). This would indicate that two types of active sites are present on the catalyst surface. It is noteworthy the high catalytic activity of this family of catalyst, since they exhibit a better performance than Cu-ZnO catalysts, but using a lower reaction temperature and H2/furfural molar ratio, as well as a higher furfural concentration and WHSV values. The experimental conditions have been optimized in order to achieve the maximum yield in the target product, but preserving a high activity and stability. The fresh and spent catalysts have been characterized in order to elucidate structure-activity-stability relationships.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

    Factors associated with postharvest ripening heterogeneity of "Hass" avocados (Persea americana Mill)

    Get PDF
    Indexación: Web of ScienceIntroduction. 'Hass' is the main avocado cultivar commercialized worldwide. The extended flowering period, very low percentage of fruit set and inability to ripen on the tree renders the fruit heterogeneous and unpredictable during postharvest management. The "triggered" and "ready-to-eat" growing markets for 'Hass' avocados are affected by the variable postharvest ripening or ripening heterogeneity which creates severe logistical problems for marketers and inconsistent quality delivery to consumers. Synthesis. The dry matter content, the current avocado harvest index that correlates very well with oil content, has been extensively used to harvest 'Hass' avocados to comply with the minimum standards to guarantee consumer satisfaction. However, previous work and empirical experience demonstrate that dry matter does not correlate on a fruit-to-fruit basis with time to reach edible ripeness. Thus, avocados of very different ages are harvested from individual trees, resulting in heterogeneous postharvest ripening of fruit within a specific batch. Several preharvest factors related to environmental and growing conditions and crop management as well as postharvest technology strategies influence the observed variability of postharvest ripening. Conclusion. Modern approaches based on studying the composition of individual fruits displaying contrasting postharvest ripening behavior, combined with non-destructive phenotyping techniques, seem to offer practical solutions for the fresh supply chain of avocados to sort fruit based on their ripening capacity.http://www.pubhort.org/fruits/2016/5/fruits160045.ht

    Dll4/Notch1 signaling from tip/stalk endothelial cell specification to stroma-dependent lung tumor inhibition: a flavor of Dll4/Notch1 pleiotropy in tumor cell biology.

    Get PDF
    Non-small cell lung cancer (NSCLC) still represents the leading cause of cancer death. Treating this disease with systemic chemotherapy has reached a plateau in effectiveness and is rather toxic to the patients, while molecularly targeted therapies against Epidermal Growth Factor Receptor can lead to resistance. On the other hand, therapies based on tumor angiogenesis inhibition have been recently proposed. Here we will discuss on the pleiotropy of the Dll4/Notch1 cell-to-cell signaling in NSCLC, as alternative target for future therapeutic approaches

    Efecto de las condiciones de almacenamiento refrigerado sobre el estrés oxidativo en raquis de uva de mesa, cv. Red Globe

    Get PDF
    Indexación: Web of Science; ScieloTable grape (Vitis vinifera L.) quality includes the condition of both the berries and the rachis. In the present report, physiological parameters of Red Globe rachises from fully elongated inflorescences (RFEI) and from mature clusters were studied after storage at 0 or 20 °C for different durations. To understand changes in rachis physiology as a result of changes in temperature conditions and storage time, the activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) were measured. In addition, hydrogen peroxide content, membrane lipoperoxidation (TBARS), total phenolic compounds and antioxidant capacity (FRAP) were assayed. TBARS was higher in mature rachises than in RFEI. This parameter remained constant throughout storage, indicating a change presumably associated with ontogeny or senescence processes. Short-term storage (096 h) increased SOD, CAT and APX activities in RFEI, while in mature rachises, no changes were observed in enzyme activities or in hydrogen peroxide content. Longer cold storage (25 or 53 days at 0 °C) of mature rachises reduced CAT activity, but SOD and APX activities did not change under these conditions. At 0 h, the FRAP and total phenolic contents of mature rachises were three and 20 times higher than in immature rachises, respectively.La calidad de uva de mesa (Vitis vinifera L.) involucra tanto la condición de bayas y el raquis. En el presente trabajo, los parámetros fisiológicos de raquis de 'Red Globe' de inflorescencias completamente elongadas (RFEI) y de racimos maduros fueron estudiados después de almacenamientos por diferentes tiempos a 0 ó 20 °C. Para entender los cambios en la fisiología del raquis debido a variaciones de temperatura y condiciones de almacenamiento, se midieron las actividades de superoxido dismutasa (SOD), catalasa (CAT), ascorbato peroxidasa (APX). Además fueron analizados el contenido de peróxido de hidrógeno, lipoperoxidación de membranas (TBARS), compuestos fenólicos totales y capacidad antioxidante (FRAP). TBARS de los raquis maduros a la cosecha fue mayor que el de inflorescencias completamente elongadas (RFEI). Este parámetro permaneció constante a través del almacenamiento, indicando cambios presuntamente asociados a ontogenia o procesos de senescencia. Almacenamiento cortos (0-96h) incrementaron la actividad de SOD, CAT y APX en RFEI, sin embargo no se observaron cambios en la actividad de estas enzimas o contenido de peróxido de hidrogeno en raquis maduros. Almacenamiento refrigerado prolongado (25 ó 30 días 0 °C) de raquis maduros redujo la actividad de CAT, pero SOD y APX no mostraron cambios bajo estas condiciones. A 0 h el contenido de FRAP y fenólicos totales de raquis maduros fueron tres y 20 veces mayores que en raquis inmaduro respectivamente.http://ref.scielo.org/m3mg4
    • …
    corecore