Agroforestry systems of timber species and cacao: survival and growth during the early stages

In recent times, increased emphasis has been placed on diversifying the types of trees to shade cacao (Theobroma cacao L.) and to achieve additional services. Agroforestry systems that include profitable and native timber trees are a viable alternative but it is necessary to understand the growth characteristics of these species under different environmental conditions. Thus, timber tree species selection should be based on plant responses to biotic and abiotic factors. The aims of this study were (1) to evaluate growth rates and leaf area indices of the four commercial timber species: Cordia thaisiana, Cedrela odorata, Swietenia macrophylla and Tabebuia rosea in conjunction with incidence of insect attacks and (2) to compare growth rates of four Venezuelan Criollo cacao cultivars planted under the shade of these four timber species during the first 36 months after establishment. Parameters monitored in timber trees were: survival rates, growth rates expressed as height and diameter at breast height and leaf area index. In the four Cacao cultivars: height and basal diameter. C. thaisiana and C. odorata had the fastest growth and the highest survival rates. Growth rates of timber trees will depend on their susceptibility to insect attacks as well as to total leaf area. All cacao cultivars showed higher growth rates under the shade of C. odorata. Growth rates of timber trees and cacao cultivars suggest that combinations of cacao and timber trees are a feasible agroforestry strategy in Venezuela.

Determination of the silvo-melliferous regions of Benin: a nationwide categorisation of the land based on melliferous plants suitable for timber production

Perennial plants are the main pollen and nectar sources for bees in the tropical areas where most of the annual flora are burned in dry seasons. Therefore perennial plants constitute the most reliable bio materials for determining and evaluating the beekeeping regions of the Republic of Benin. A silvo-melliferous region (S-MR) is a geographical area characterised by a particular set of homogenous melliferous plants that can produce timber. Using both the prevailing climatic and the agro-ecological conditions six S-MRs could be identified, i.e. the South region, the Common Central region, the Central West region, the Central North region, the Middle North region and the Extreme North region. At the country level, the melliferous plants were dominated by Vitellaria paradoxa which is common to all regions. The most diversified family was the Caesalpiniaceae (12 species) followed by the Combretaceae (10 species) and Combretum being the richest genus. The effect of dominance is particularly high in the South region where Elaeis guineensis alone represented 72.6% of the tree density and 140% of the total plant importance. The total melliferous plant density varied from 99.3 plants ha^(−1) in the Common Central region to 178.0 plants ha^(−1) in the Central West region. On the basis of nectar and pollen source, the best region for beekeeping is the CentralWest region with 46.7% of nectar producing trees, 9.4% of pollen producing trees and 40.6% of plants that issue both, this in opposition to the South region which was characterised by an unbalanced distribution of melliferous trees.

Logistics Network Design with Differentiated Delivery Lead-Time: Benefits and Insights

Most logistics network design models assume exogenous customer demand that is independent of the service time or level. This paper examines the benefits of segmenting demand according to lead-time sensitivity of customers. To capture lead-time sensitivity in the network design model, we use a facility grouping method to ensure that the different demand classes are satisfied on time. In addition, we perform a series of computational experiments to develop a set of managerial insights for the network design decision making process.

Apatite-Polymer Composites for the Controlled Dual Delivery of BMP-2 and BMP-6 for Bone Tissue Engineering

The release of growth factors from tissue engineering scaffolds provides signals that influence the migration, differentiation, and proliferation of cells. The incorporation of a drug delivery platform that is capable of tunable release will give tissue engineers greater versatility in the direction of tissue regeneration. We have prepared a novel composite of two biomaterials with proven track records - apatite and poly(lactic-co-glycolic acid) (PLGA) – as a drug delivery platform with promising controlled release properties. These composites have been tested in the delivery of a model protein, bovine serum albumin (BSA), as well as therapeutic proteins, recombinant human bone morphogenetic protein-2 (rhBMP-2) and rhBMP-6. The controlled release strategy is based on the use of a polymer with acidic degradation products to control the dissolution of the basic apatitic component, resulting in protein release. Therefore, any parameter that affects either polymer degradation or apatite dissolution can be used to control protein release. We have modified the protein release profile systematically by varying the polymer molecular weight, polymer hydrophobicity, apatite loading, apatite particle size, and other material and processing parameters. Biologically active rhBMP-2 was released from these composite microparticles over 100 days, in contrast to conventional collagen sponge carriers, which were depleted in approximately 2 weeks. The released rhBMP-2 was able to induce elevated alkaline phosphatase and osteocalcin expression in pluripotent murine embryonic fibroblasts. To augment tissue engineering scaffolds with tunable and sustained protein release capabilities, these composite microparticles can be dispersed in the scaffolds in different combinations to obtain a superposition of the release profiles. We have loaded rhBMP-2 into composite microparticles with a fast release profile, and rhBMP-6 into slow-releasing composite microparticles. An equi-mixture of these two sets of composite particles was then injected into a collagen sponge, allowing for dual release of the proteins from the collagenous scaffold. The ability of these BMP-loaded scaffolds to induce osteoblastic differentiation in vitro and ectopic bone formation in a rat model is being investigated. We anticipate that these apatite-polymer composite microparticles can be extended to the delivery of other signalling molecules, and can be incorporated into other types of tissue engineering scaffolds.

Apatite-Polymer Composite Particles for Controlled Delivery of BMP-2: In Vitro Release and Cellular Response

Bone morphogenetic protein-2 (BMP-2) has the ability to induce osteoblast differentiation of undifferentiated cells, resulting in the healing of skeletal defects when delivered with a suitable carrier. We have applied a versatile delivery platform comprising a novel composite of two biomaterials with proven track records – apatite and poly(lactic-co-glycolic acid) (PLGA) – to the delivery of BMP-2. Sustained release of this growth factor was tuned with variables that affect polymer degradation and/or apatite dissolution, such as polymer molecular weight, polymer composition, apatite loading, and apatite particle size. The effect of released BMP-2 on C3H10T1/2 murine pluripotent mesenchymal cells was assessed by tracking the expression of osteoblastic makers, alkaline phosphatase (ALP) and osteocalcin. Release media collected over 100 days induced elevated ALP activity in C3H10T1/2 cells. The expression of osteocalcin was also upregulated significantly. These results demonstrated the potential of apatite-PLGA composite particles for releasing protein in bioactive form over extended periods of time.

Targeted Stimuli-Responsive Dextran Conjugates for Doxorubicin Delivery to Hepatocytes

A targeted, stimuli-responsive, polymeric drug delivery vehicle is being developed in our lab to help alleviate severe side-effects caused by narrow therapeutic window drugs. Targeting specific cell types or organs via proteins, specifically, lectin-mediated targeting holds potential due to the high specificity and affinity of receptor-ligand interactions, rapid internalization, and relative ease of processing. Dextran, a commercially available, biodegradable polymer has been conjugated to doxorubicin and galactosamine to target hepatocytes in a three-step, one-pot synthesis. The loading of doxorubicin and galactose on the conjugates was determined by absorbance at 485 nm and elemental analysis, respectively. Conjugation efficiency based on the amount loaded of each reactant varies from 20% to 50% for doxorubicin and from 2% to 20% for galactosamine. Doxorubicin has also been attached to dextran through an acid-labile hydrazide bond. Doxorubicin acts by intercalating with DNA in the nuclei of cells. The fluorescence of doxorubicin is quenched when it binds to DNA. This allows a fluorescence-based cell-free assay to evaluate the efficacy of the polymer conjugates where we measure the fluorescence of doxorubicin and the conjugates in increasing concentrations of calf thymus DNA. Fluorescence quenching indicates that our conjugates can bind to DNA. The degree of binding increases with polymer molecular weight and substitution of doxorubicin. In cell culture experiments with hepatocytes, the relative uptake of polymer conjugates was evaluated using flow cytometry, and the killing efficiency was determined using the MTT cell proliferation assay. We have found that conjugate uptake is much lower than that of free doxorubicin. Lower uptake of conjugates may increase the maximum dose of drug tolerated by the body. Also, non-galactosylated conjugate uptake is lower than that of the galactosylated conjugate. Microscopy indicates that doxorubicin localizes almost exclusively at the nucleus, whereas the conjugates are present throughout the cell. Doxorubicin linked to dextran through a hydrazide bond was used to achieve improved killing efficiency. Following uptake, the doxorubicin dissociates from the polymer in an endosomal compartment and diffuses to the nucleus. The LC₅₀ of covalently linked doxorubicin is 7.4 μg/mL, whereas that of hydrazide linked doxorubicin is 4.4 μg/mL.

Diseño del plan exportador para la empresa Creaciones J&D

Creaciones J&D es una empresa de confecciones creada en al año 2001 por su actual gerente general, gracias a la información suministrada por el gerente se lleva a cabo el desarrollo del Plan Exportador de la empresa en donde se tomo en cuenta una serie de variables para identificar el segmento de mercado y tipo de cliente al que se va a exportar. Por medio del uso de una serie de variables analizadas en el desarrollo del proceso para el inicio de una actividad de exportación ayudamos a esta PYME a facilitar su proceso de internacionalización a mediano plazo, dependiendo de la experiencia y resultados en el mercado objetivo a largo plazo será probable vender los productos comercialmente por medio de marca y prestigio. De esta forma hemos desarrollado este trabajo teniendo en cuenta estos factores, para poder lograr las metas de exportación, la empresa debe generar un plan de trabajo para que en tres años se encuentre exportando y por ello se plantea actividades a realizar para continuar explorando los mercados que hacen parte de la CAN. La recomendación es concentrarse en la ventaja competitiva del diseño y calidad del producto, en cuanto a su capacidad productiva, es poder garantizar los tiempos de entrega usando empresas satélites y demás medios que maximicen utilidades y optimicen tiempo, para tener una capacidad de respuesta a la altura de los mercados internacionales.

Caches and Content Delivery

Getting content from server to client can be more complicated than we have discussed so far. This lecture discusses how caching and content delivery networks help to make the Web work.

Plan de empresa Restaurante Il Mistero

IL MISTERO es un proyecto de plan de empresa que se dedicara a la elaboración y venta especializada de lasañas y otros platos italianos en establecimiento local y a domicilio en la ciudad de Bogotá, específicamente en la localidad de Chapinero, Upz Chico alto, zona que posee potencial económico. Su portafolio de productos está dividido en alimentos y bebidas, siendo alimentos el grupo por el cual obtendrá su mayor ingreso de ventas. Su producto estrella serán las lasañas, con las que contara inicialmente de una oferta de ocho recetas, además de los demás platos como pastas, ensaladas, sopas, y postres. La totalidad de productos son hechos en cocina son elaborados artesanalmente con un enfoque de comida saludable, lo cual significa que no contienen ningún tipo de colorantes o químicos. La operación contara con un local comercial con comedor, pero se estima que una de sus grandes fortalezas será la venta a domicilio, ya que es un producto rápido, fácil de empacar y atractivo para el cliente. Con esto se busca atender tanto al cliente que desea disfrutar un momento en un restaurante, como al que por pereza, comodidad, o gusto prefiere comer en casa u oficina. Para poder desarrollar el proyecto se requerirán recursos por 199,9 millones de pesos para la adquisición de activos fijos y capital del trabajo. Dicha inversión será recuperada al tercer año de operación si todos los presupuestos se cumplen. El aumento de ventas se lograran por medio de la inversión en publicidad y el famoso voz a voz que tanto afecta a los restaurantes. Se espera que desde el inicio del proyecto hasta el año 2 sean crecientes, y en él años 3 se logre una estabilidad en la demanda.

Small-area variation in health care affecting the choice of cesarean delivery: the case of a Colombian health insurer

In the midst of health care reform, Colombia has succeeded in increasing health insurance coverage and the quality of health care. In spite of this, efficiency continues to be a matter of concern, and small-area variations in health care are one of the plausible causes of such inefficiencies. In order to understand this issue, we use individual data of all births from a Contributory-Regimen insurer in Colombia. We perform two different specifications of a multilevel logistic regression model. Our results reveal that hospitals account for 20% of variation on the probability of performing cesarean sections. Geographic area only explains 1/3 of the variance attributable to the hospital. Furthermore, some variables from both demand and supply sides are found to be also relevant on the probability of undergoing cesarean sections. This paper contributes to previous research by using a hierarchical model and by defining hospitals as cluster. Moreover, we also include clinical and supply induced demand variables.

¿De dónde sale el papel con el que se hacen los libros? : investigando con cuatro años.

Investigar es una palabra muy grande, tanto como la capacidad de aprender de un niño de cuatro años. Las autoras muestran el proyecto de investigación llevado a cabo en el 2006, centrado en el fomento de la escritura activa y en el concepto de ecología y desarrollo sostenible.

Nuestra biblioteca sale a las aulas.

Trabajo no publicado

Personal writing goes public : social commentary on women's lives in Carme Riera's 'Temps d'una espera'. 'Lo personal sale al público : comentario social sobre la situación de la mujer en 'Temps d'una espera' de Carme Riera'.

Resumen en español

El que se mueva, no sale en la foto.

Se plantea un estudio de casos con el objetivo de clarificar y discernir de los conflictos que se plantean hoy en día en las escuelas y que deben solucionar los profesores. La raiz de los conflictos clásicos (jaleo, impertinencias, pintar paredes, etc.) ha estado muchas veces en una falta de recursos pedagógicos de los profesores y en una relativa dejación de la dirección del centro y del clima de la comunidad educativa. Los nuevos conflitos (alcohol, drogas, armas, etc.) provienen de fuera del aula, aunque se le suma un sistema de educación secundaria no preparada para estos conflictos..

El currículo de Ciencias Sociales sale del aula : fútbol y cultura clásica en el Paseo del Prado.

Se presenta la experiencia realizada con los alumnos de cuarto de ESO en un colegio madrileño, para completar el currículum de Ciencias Sociales utilizando la ciudad de Madrid como recurso pedagógico. Un recorrido interdisciplinar a caballo entre la asignatura de Cultura Clásica y la Historia; paseando por el antiguo Salón del Prado y el reinado de Carlos III. Como punto de partida, el principal interés de los alumnos, el fútbol. Se describe la actividad realizada con los alumnos fuera del aula, partiendo de los objetivos, los contenidos, expone diversas estrategias metodológicas para la realización de la salida y, finalmente, se presenta la experiencia, exponiendo la organización y distribución del trabajo, así como el material y las fuentes para el mismo.