Planting date, storage and gibberellic acid affect dormancy of Zantedeschia Spreng. hybrids : a thesis presented in partial fulfilment of the requirements for the degree of Masters in Applied Science, Massey University, Palmerston North, New Zealand

To match the supply of Zantedeschia cut flowers and tubers to the demands of the international market, crops have to be timed to a schedule, which requires control of the growth cycle and, in particular, dormancy. In order to improve the predictability and accuracy of timing of Zantedeschia, the effect of different planting seasons and two dormancy-breaking treatments were tested on cultivars 'Black Magic' and 'Treasure', which were known to have a contrasting level of dormancy. Tissue-cultured plants were ex-flasked in July and November 1999, and grown for 180 days in a heated glasshouse (first cycle). Between 120 and 180 days of growth, plants were harvested at 15 days intervals, and tubers cured. Subsequently, tubers were stored for 0 or 3 weeks (10 ± 1°C; 70-80% RH) and dipped in 100 mg.L -1 gibberellic acid plus surfactant or water plus surfactant, prior to planting for dormancy assessment (second cycle). Growing the plants with four months difference in planting date did not cause major alteration in the occurrence of dormancy. Dormancy was brought forward by up to 10 days after the November date of ex-flask, but this was most likely to be due to higher temperatures during that period. In contrast, depth of dormancy varied between cultivars, with 'Black Magic' taking in average 16 days longer to emerge than 'Treasure'. Storage partially released bud dormancy of the tubers. It increased emergence to over 80% regardless of the time of harvest in the first cycle and cultivar, but reduced time to emergence mostly after harvests at 180 days. Furthermore, following storage, time to emergence was reduced to over 50 and 30 days for 'Black Magic' and 'Treasure', respectively, which exceeded the commercially acceptable period to emerge. Gibberellic acid also broke bud dormancy, improving emergence to over 80%, and reduced time to emergence to between 29 and 57 days, irrespective of the time of harvest in the first cycle and cultivar. The effectiveness of gibberellic acid at any time following harvest during the first cycle, may imply that dormancy of Zantedeschia is not as deep as in temperate woody plants. Cessation of leaf emergence in the first cycle was found not to be directly related to the occurrence of dormancy. Degree-days, on the other hand, presented a possible alternative to predict this process. It was estimated that deepest dormancy of 'Black Magic' occurred between 2614 and 2732 °C-days after planting, while deepest dormancy of 'Treasure' occurred between 2681 and 2839 °C-days after planting. The present study presents storage and gibberellic acid as possible options to control dormancy, and the use of degree-days to predict the occurrence of this process. Further research is necessary to develop these options as commercially applicable practices, and to further clarify the process of dormancy in Zantedeschia

Reactivity indexes for different geometries of palladium leads

Electronic transport through metallic break junctions or molecules is clearly dependent not only on the electronic structure of the central nanodevice connecting the leads, but also the shape and crystalline orientation of the contacts which can define the possible conduction channels. In this work we examine different geometries of contacts of palladium characterizing them through global and local reactivity indexes as electrophilicity, chemical hardness and Fukui functions. In molecules, these indicators are essentially defined by the energies of the frontier molecular orbitals and in solids they are related with the local and partial density of states. We use for this purpose an ab-initio based code (FIREBALL), applied to plane contacts with (001) fcc faces and also pyramidal tips grown following a (001) and (111) packaging. The results allow us to have an insight about the chemical features of this type of nanojunctions.Fil: Gómez Carrillo, Sandra Carolina. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Departamento de Física; ArgentinaFil: Ortega, J.. Universidad Autónoma de Madrid; EspañaFil: Bolcatto, Pablo Guillermo. Universidad Nacional del Litoral; Argentin

Nanoscale metal–organic frameworks as key players in the context of drug delivery: evolution toward theranostic platforms

This is a post-peer-review, pre-copyedit version of an article published in Analytical and Bioanalytical Chemistry. The final authenticated version is available online at: https://doi.org/10.1007/s00216-019-02217-yMetal–organic frameworks (MOFs) have emerged as one of the most fascinating libraries of porous materials with a huge potential in very diverse application areas. In particular, the bioanalytical and biomedical fields have evolved tremendously due to the emergence of these hybrid inorganic–organic MOF-based materials. This is because these materials possess a series of key properties essential for bioapplications, such as minimal toxicity to living cells, intrinsic biodegradability, and possibility of synthesizing with nanoscale sizes. Additional properties of MOFs such as ultra-large surface-to-volume ratios, tunable pore size, high drug loading capacity, tunable structure and chemical composition, and potential for multiple postsynthetic modification make them ideal candidates for drug delivery. This review highlights recent research progress on MOF-based drug delivery systems (DDS), pointing out the evolution of these systems toward the development of theranostic nanoplatforms. Rather than a comprehensive review, representative recent examples are selected to illustrate such an evolution, and a critical discussion of the advantages and limitations of the different DDS types is given. Finally, the remaining challenges and future opportunities in this field are presented, highlighting that overcoming the current issues will pave the way toward the elusive dream of “personalized medicine.”C.C.C. thanks the financial support from the European Union under the H2020-MSCA-IF-2016 program (MSCA-IF-EF-ST Grant Agreement No. 749667)S

Study for the ERP implementation in a land transport company

El siguiente escrito muestra un estudio de implementación con el cual una ERP puede ser la mejor opción para ayudar a la gestión de procesos operativos de todo tipo de empresas, pero fundamentalmente en una empresa de transporte terrestre de mercancía donde existe un problema latente en la gestión de las tareas diarias que constituye la parte fundamental de su operatividad.The following letter shows an implementation study in which an ERP can be the best option to help manage operational processes of all types of companies, but primarily in a trucking company merchandise where a latent problem in the management of daily tasks that constitute the core of its operations. This shows a theoretical part where you have to know everything that involves the term ERP and its implementation process

El carácter evolutivo de las prácticas sociales. El caso de la predicción

Este escrito reporta los resultados de una investigación de tipo histórico epistemológico acerca del carácter evolutivo de las prácticas sociales, constructo teórico fundamental en la aproximación socioepistemológica a la investigación en Matemática Educativa. En particular esta investigación analiza, cómo se concibe a la predicción desde la Socioepistemología y hace un recorrido histórico conceptual alrededor de la génesis y el posterior desarrollo de los fractales. Una comparación de estos dos análisis nos hace concluir que todo el conocimiento, las herramientas y la teoría creados en torno a los fractales fueron guiados por la práctica social de la predicción. Se muestra así una evolución de la práctica social de la predicción caracterizándola en predicción determinista y predicción no determinista

Identificación y análisis de las actitudes hacia la estadística en estudiantes de nivel medio superior

Analizando investigaciones actuales de la Matemática Educativa parece innegable que el aprendizaje está íntimamente ligado a las características cognitivas de nuestros estudiantes, en contraparte las investigaciones en el ámbito afectivo, aunque es un campo creciente, aún representan un pequeño porcentaje. Aspectos endógenos de los estudiantes como la motivación, los valores y las actitudes están presentes frecuentemente en los objetivos curriculares, sin embargo, no es claro cómo crear las condiciones que fomenten su desarrollo. En esta investigación nos enfocamos de manera particular en las actitudes hacia la estadística en estudiantes de nivel medio superior. Nuestro interés se centra en identificar y analizar estas actitudes, ya que como dejan ver Gairín (1987), Gómez-Chacón (2000), Castro (2002), las actitudes juegan un papel muy importante en el proceso enseñanza aprendizaje de la matemática, por este motivo creemos conveniente primero identificarlas y analizarlas para después crear las condiciones que fomenten las actitudes positivas y mejoren las negativas

Analytical strategies based on quantum dots for heavy metal ions detection

Heavy metal contamination is one of the major concerns to human health because these substances are toxic and retained by the ecological system. Therefore, in recent years, there has been a pressing need for fast and reliable methods for the analysis of heavy metal ions in environmental and biological samples. Quantum dots (QDs) have facilitated the development of sensitive sensors over the past decade, due to their unique photophysical properties, versatile surface chemistry and ligand binding ability, and the possibility of the encapsulation in different materials or attachment to different functional materials, while retaining their native luminescence property. This paper comments on different sensing strategies with QD for the most toxic heavy metal ions (i.e., cadmium, Cd2+; mercury, Hg2+; and lead, Pb2+). Finally, the challenges and outlook for the QD-based sensors for heavy metals ions are discussedM.V.G. thanks the MICINN for the PhD grant (FPI, BES-2010-032652). C.C.C. acknowledges a postdoctoral fellowship from the Alexander von Humboldt FoundationS

Diseño de gráficas a partir de actividades de modelación

Este documento reporta los resultados obtenidos de tres situaciones de aprendizaje aplicadas en diversos talleres con profesores de matemáticas cuya actividad central es dar cuenta de una situación de movimiento a partir del contraste de dos gráficas, una generada con las concepciones propias sobre el movimiento y otra generada por una calculadora a través de datos obtenidos por un sensor. Se observan elementos para ampliar la gama de situaciones de movimiento con los que se puede caracterizar un nuevo uso de las gráficas

Pymes colombianas, preparadas para enfrentar el comercio internacional

Las pyme se han convertido en focos de desarrollo y son herramientas clave para el crecimiento de las economías, de acuerdo, a su importante participación en la generación de empleo y gracias a que contribuyen a una distribución del ingreso más equitativa, lo cual conlleva a satisfacer las necesidades básicas de los habitantes de un país, del mismo modo las pyme, se han convertido en la opción más viable para generar crecimiento, productividad y competitividad en el sector empresarial mundial, por lo cual, este documento analiza la potencialidad de las pyme para la competitividad en el comercio mundial, teniendo en cuenta las variables macroeconómicas que se interrelacionan y sus efectos en la economía nacional, como resultado se determino que las pymes colombianas no están preparadas actualmente para enfrentar los retos que exige la internacionalización, sin embargo se considera que la conformación de clúster es la estrategia más adecuada e indispensable que permite la creación de economías a escala, asegurando el ingreso al mercado mundial y logrando competitividad a nivel internacional, por otro lado, se benefician de la capacidad de interconectarse para ser proveedoras directas de las grandes empresas exportadoras, pues de lo contrario la viabilidad de las pyme se vería reducida al mercado local.The Small Medium Enterprises (SME) have become centers of development and are a key tool for developing economies, according to their important role in generating employment and by contributing to a more equitable income distribution, which leads to meeting basic needs of the habitants of a country, at the same time the SME, have become the most viable option for growth, productivity and competitiveness in the global business sector, so, this document analyzes the potential of SME to competitiveness in world trade, taking into account the macroeconomic variables are interrelated and their effects on the national economy, as a result, it was determined that the Colombian SME aren't ready to face the internationalization process challenges, however it is considered the formation of cluster is the best strategy appropriate and necessary to allow the creation of economies of scale, ensuring entry into the world market and achieving international competitiveness, on the other hand, benefit from the ability to interface to be direct providers of large exporters, otherwise the viability of SME s will be reduced to the local market

Todo lo que quería saber sobre el diagnóstico de COVID-19 y nunca se animó a preguntar

En el marco de la pandemia mundial COVID-19, Argentina anunció la emergencia sanitaria a través de su Boletín Oficial del 17 de Marzo de 2020. El CONICET en conjunto con el Ministerio de Ciencia, Tecnología e Innovación, y la Agencia Nacional de Promoción de la Investigación, el Desarrollo Tecnológico y la Innovación (Agencia I+D+i), crearon la "Unidad Coronavirus COVID-19" destinada a brindar respuesta a las demandas y necesidades inmediatas del Poder Ejecutivo Nacional y el Ministerio de Salud de la Nación. Uno de los ejes de la Unidad se centró en el desarrollo de nuevos kits de diagnóstico.Fil: Carrillo, Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Ciencia y Tecnología "Dr. César Milstein". Fundación Pablo Cassará. Instituto de Ciencia y Tecnología "Dr. César Milstein"; Argentin