58 research outputs found

    Producción agroecológica de leche en el trópico de altura: sinergia entre restauración ecológica y sistemas silvopastoriles

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    Climate change and the inequality of the global trade of dairy products have seriously affected small milk producers who have adopted an artificial model based on industrial inputs and the extreme genetic specialization of livestock. Although the application of agroecological principles and the growing demand for natural foods indicate an escape route for these producers, agroecological milk production is not easy because the transition requires making difficult decisions that can affect short term productivity. This article summarizes the agroecological transition of a small dairy farm in the central Andes of Colombia.The starting point was the conventional model typical of many mountain dairies in Latin America, based on grass monocultures fertilized with urea and the supplementation of cows with feedstuffs made from imported cereals and soy cake. By adopting increasingly complex silvopastoral systems and phasing out farm chemical inputs this farm managed to reduce the production costs and increase the quality and price of its milk while improving food security and energy efficiency. Adding value to the organic milk is the final challenge that will improve the profitability of the farming system.El cambio climático y la inequidad que caracteriza al comercio global de los productos lácteos han golpeado duramente a los pequeños productores de leche que adoptaron un modelo artificial dependiente de insumos industriales y una exagerada especialización genética del ganado. Aunque la aplicación de los principios agroecológicos y la demanda creciente de alimentos naturales señalan una ruta de escape para estos productores, la producción agroecológica de leche no es fácil porque la etapa de transición exige tomar decisiones difíciles que pueden afectar la productividad en el corto plazo. Este artículo narra la transición agroecológica de una pequeña finca lechera en los Andes centrales de Colombia. El punto de partida fue el modelo convencional característico de muchas lecherías de montaña en América Latina, basado en monocultivos de gramíneas fertilizados con urea y la suplementación de las vacas con alimentos concentrados elaborados a partir de cereales y torta de soya importados. Mediante la adopción de sistemas silvopastoriles cada vez más complejos y la eliminación gradual de los insumos agroquímicos, la finca logró reducir el costo de producción de la leche, aumentar la calidad y el precio de la misma y mejorar la seguridad alimentaria y la eficiencia energética. El reto final será agregarle valor a la leche orgánica para aumentar la rentabilidad del sistema

    PROMISCUOUS: a database for network-based drug-repositioning

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    The procedure of drug approval is time-consuming, costly and risky. Accidental findings regarding multi-specificity of approved drugs led to block-busters in new indication areas. Therefore, the interest in systematically elucidating new areas of application for known drugs is rising. Furthermore, the knowledge, understanding and prediction of so-called off-target effects allow a rational approach to the understanding of side-effects. With PROMISCUOUS we provide an exhaustive set of drugs (25 000), including withdrawn or experimental drugs, annotated with drug–protein and protein–protein relationships (21 500/104 000) compiled from public resources via text and data mining including manual curation. Measures of structural similarity for drugs as well as known side-effects can be easily connected to protein–protein interactions to establish and analyse networks responsible for multi-pharmacology. This network-based approach can provide a starting point for drug-repositioning. PROMISCUOUS is publicly available at http://bioinformatics.charite.de/promiscuous

    Development of Immune-Specific Interaction Potentials and Their Application in the Multi-Agent-System VaccImm

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    Peptide vaccination in cancer therapy is a promising alternative to conventional methods. However, the parameters for this personalized treatment are difficult to access experimentally. In this respect, in silico models can help to narrow down the parameter space or to explain certain phenomena at a systems level. Herein, we develop two empirical interaction potentials specific to B-cell and T-cell receptor complexes and validate their applicability in comparison to a more general potential. The interaction potentials are applied to the model VaccImm which simulates the immune response against solid tumors under peptide vaccination therapy. This multi-agent system is derived from another immune system simulator (C-ImmSim) and now includes a module that enables the amino acid sequence of immune receptors and their ligands to be taken into account. The multi-agent approach is combined with approved methods for prediction of major histocompatibility complex (MHC)-binding peptides and the newly developed interaction potentials. In the analysis, we critically assess the impact of the different modules on the simulation with VaccImm and how they influence each other. In addition, we explore the reasons for failures in inducing an immune response by examining the activation states of the immune cell populations in detail

    Amazon region: eco-efficient landscapes

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    The Amazon Basin is so diverse that one could say many Amazons exist, not just one. Indeed, its diversity is considered unique in the world. Although the Basin occupies 7% of the planet’s land, it carries 25% of the world’s terrestrial biodiversity. The region is so vast, it represents one-third of South America’s land surface. It covers, or partly covers, nine countries: Colombia (36% of the land area), Venezuela and Guyana (6% each), Suriname and French Guiana (almost 100% each), Brazil (60%), Bolivia and Peru (75% together), and Ecuador (45%)

    Diversidad zoológica asociada a un silvopastoreo leucaena-guinea con diferentes edades de establecimiento

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    El objetivo de este trabajo fue evaluar la diversidad zoológica asociada a un silvopastoreo con leucaena-guinea, por medio de la caracterización de la composición y estructura de las aves, insectos y la macrofauna del suelo, en cuatro edades de establecimiento (3, 4, 5 y 6 años de explotación). Con las especies registradas en cada uno de estos grupos zoológicos, se calcularon los índices ecológicos: número de individuos, riqueza, diversidad y abundancia de especies, en diferentes edades del sistema. En todos los grupos, se apreció el aumento significativo en la riqueza de especies y en el índice de diversidad biológica de Shannon, en la medida que se desarrolló el sistema. Se observó incremento en la abundancia de insectos biorreguladores y, en relación con las aves, el horario de muestreo no mostró interacción con los distintos años de siembra. La macrofauna se incrementó, observándose dominancia de anélidos al 6º y 7º año de explotación, caracterizado por Polyferetrina elongata y Oligochaeta elegans. El desarrollo del silvopastoreo leucaena-guinea logra sistemas productivos pecuarios que aumentan la producción de biomasa y de otros componentes biológicos y contribuir para crear un sistema sostenible y compatible con el ambiente

    The impact of surgical delay on resectability of colorectal cancer: An international prospective cohort study

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    AIM: The SARS-CoV-2 pandemic has provided a unique opportunity to explore the impact of surgical delays on cancer resectability. This study aimed to compare resectability for colorectal cancer patients undergoing delayed versus non-delayed surgery. METHODS: This was an international prospective cohort study of consecutive colorectal cancer patients with a decision for curative surgery (January-April 2020). Surgical delay was defined as an operation taking place more than 4 weeks after treatment decision, in a patient who did not receive neoadjuvant therapy. A subgroup analysis explored the effects of delay in elective patients only. The impact of longer delays was explored in a sensitivity analysis. The primary outcome was complete resection, defined as curative resection with an R0 margin. RESULTS: Overall, 5453 patients from 304 hospitals in 47 countries were included, of whom 6.6% (358/5453) did not receive their planned operation. Of the 4304 operated patients without neoadjuvant therapy, 40.5% (1744/4304) were delayed beyond 4 weeks. Delayed patients were more likely to be older, men, more comorbid, have higher body mass index and have rectal cancer and early stage disease. Delayed patients had higher unadjusted rates of complete resection (93.7% vs. 91.9%, P = 0.032) and lower rates of emergency surgery (4.5% vs. 22.5%, P < 0.001). After adjustment, delay was not associated with a lower rate of complete resection (OR 1.18, 95% CI 0.90-1.55, P = 0.224), which was consistent in elective patients only (OR 0.94, 95% CI 0.69-1.27, P = 0.672). Longer delays were not associated with poorer outcomes. CONCLUSION: One in 15 colorectal cancer patients did not receive their planned operation during the first wave of COVID-19. Surgical delay did not appear to compromise resectability, raising the hypothesis that any reduction in long-term survival attributable to delays is likely to be due to micro-metastatic disease

    Diversity and use of the calabash tree (Crescentia cujete L.) in Colombia

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