Search

Background/Objectives: A case study is presented where a 1.432 MW wind power connection with DFIG (doubly-fed induction generator) technology is analyzed in the stability of the National Transmission System (NTS). Hence, the STN’s database from 2017 is used in DIgSILENT with different demand scenarios and their respective generation dispatch units. Methods/Statistical Analysis: A scan was executed on the flaws in circuits close to the connection of wind energy parks in La Guajira by calculating the percentage of events that generate the disconnection of wind turbines due to voltage sags and swells. The stability in frequency in response to these generation losses is also analyzed. Findings: Regarding the contingencies that were simulated, the outcome was seen in overshoot events of wind turbines due to transitory peaks in voltage during flaws that could not be solved with external reactive compensation. The stability in frequency related to these overshoots is greatly affected on disconnections higher than 400 MW. After verifying the reactive power injection from the converter of the DFIG model in DIgSILENT based on the compliance with electrical parameters supplied by manufacturers, 58% did not meet these technical specifications so a wind turbine model is necessary to grasp the internal operation of the converter. Conclusion: This allows the identification of possible solutions to stability issues that contribute to the operational and regulatory changes to define technical technology-related requirements and the connection of wind turbines in Colombia. Keywords: DFIG Wind Turbine, DIgSILENT, Stability, Voltage Supportability, Wind Energy

El Hepatozoon canis es un protozoario que parasita los leucocitos de los caninos, su huésped definitivo es la garrapata común (Riphicephalus sanguineus) y el perro es el huésped intermediario, el cual adquiere la infección al ingerir una garrapata infectada con el parásito, este continúa su multiplicación y diseminación en el perro ocasionando sintomatología y daños multisistémicos en el organismo (1). La hepatozoonosis canina es una enfermedad poco estudiada y confundida a nivel mundial con otras enfermedades transmitidas por garrapatas como lo son la Babesiosis y la Ehrlichiosis al presentar cuadros clínicos similares en los pacientes. En el reporte de este caso se evidenció un cuadro clínico poco especíifico con la enfermedad la cuál fue confirmada mediante frotis sanguíneo y observación microscópica al ser una de las formas más adecuadas para la diferenciación del parásito por su morfología específica. Los pacientes con Hepatozoon canis pueden ser asintomáticos o presentar variación en su sintomatología (2). Los pocos reportes a nivel mundial sobre el Hepatozoon canis llevan a un desconocimiento de clínicos y propietarios los cuales descartan la enfermedad y relacionan su sintomatología con otras enfermedades logrando así la no identificación de este protozoo, un mal abordaje y la no resolución del problema. Por esta razón la importancia de reportar y describir este caso clínico, para elaborar guías de abordaje clínico basados en la evidencia, los cuales sean de fácil acceso para los médicos veterinarios (3 Hepatozoon canis is a protozoan that parasitizes canine leukocytes, its definitive host is the common tick (Riphicephalus sanguineus) and the dog is the intermediate host, which acquires the infection by ingesting a tick infected with the parasite, it continues its multiplication and dissemination in the dog causing symptoms and multisystemic damage in the body. Canine hepatozoonosis is a disease little studied and confused worldwide with other diseases transmitted by ticks such as Babesiosis and Ehrlichiosis, as it presents similar clinical pictures in patients. In the report of this case, nonspecific clinical picture with the desease was evidenced which was confirmed by blood smear and microscopic observation as it is one of the most appropriate ways for the differentiation of the parasite due to its specific morphology, patients with Hepatozoon canis can be asymptomatic or present variation in their symptoms. The few reports worldwide on Hepatozoon canis lead to a lack of knowledge of clinicians and owners who rule out the disease and relate its symptoms to other diseases, thus achieving a poor approach and nonresolution of the problem. For this reason, the importance of reporting and describing this clinical case, to develop evidence- based medical approach guides which are easily accessible to veterinarians. Pregrado Médico(a) Veterinario(a) y Zootecnista

Cooking quality for consumer acceptance of boiled cassava is an essential criteria for breeding programs. Selecting improved genotypes for cooking quality is increasingly important to maximize the likelihood of adoption, in addition to agronomic criteria such as yields and tolerance to pests and diseases. Conventional tests of cooking quality, such as probing the product's softness with a fork to determine optimum cooking time (CT), are time-consuming and labor intensive; requiring up to one hour per genotype. Hence, in a standard food-quality lab, only a few dozen of samples can be screened per day, whereas selection for breeding requires testing up to several hundred genotypes. The RTBfoods project has developed a faster method by objectively measuring water absorption, root density and texture. Among these, water absorption and change in root density after 30 minutes of boiling significantly correlated with CT (R2 = 0.60 to 0.66). Thus, this approach makes it possible to screen up to 80 genotypes per day by confidently classifying short-cooking and long-cooking behaviors of cassava roots, i.e. medium- throughput screening. Accumulating further cooking quality data will facilitate ongoing efforts to develop a true high-throughput phenotyping platform with the capacity to screen the target several hundred samples per day. A particularly promising approach is the ongoing investigation of correlations between cooking quality parameters and near-infrared spectroscopy (NIRS), which would reduce the analysis time from 30 to 2 minutes per genotype.

236 genotypes of the CIAT germplasm collection representative of seven diversity groups of Latin America (Amazon, Andean, Caribbean, Savanna, Dry Atlantic forest, Humid Atlantic forest, and South American rainforest) were grown at CIAT during 2014-2017. Roots from each group showed specific postharvest quality traits. Savanna, Caribbean, and South American rainforest genotypes had the highest dry matter (39.0-39.8% wb). Andean genotypes had the lowest cyanide content and shortest boiling time (average 109 ppm db and 34 mins, respectively). In contrast, Amazon genotypes had the highest cyanide content and longest cooking time (average 885 ppm db and 56 mins, respectively). These traits may reflect different selection criteria corresponding to different uses over centuries of cassava domestication: In the Andean region, cassava is commonly consumed as boiled fresh roots, and hence low cyanide and short boiling time traits may have been preferentially selected. In the Amazon region cassava is fermented to prepare farinha; for which boiling time and cyanide are less important traits. Humid Atlantic forest and Savanna genotypes had the lowest and highest postharvest physiological deterioration (PPD) at respectively 22% and 43%. Across diversity groups, the majority of genotypes had relatively low cyanide with 137 out of 236 below 200 ppm db.

Cassava is the major staple food of tropical Africa roots whereas leaves are mostly considered as a byproduct which are good source of protein, vitamins and minerals also they are available throughout the year and they should be accorded as much importance as the roots. A concern however is the risk of cyanide formation if leaves are insufficiently processed since these contain the cyanogenic glycosides linamarin (approximately 93% of total glucosides; 2-(β-D-glucopyranosyloxy)isobutyronitrile; derived from valine) and lotaustralin (2-(β-D-glucopyranosyloxy)- 2-methylbutyronitrile, derived from isoleucine). Fortunately, there are simple processes that remove the HCN from the leaves making them available for animal and human consumption. Trials with 50 cassava genotypes (Manihot esculenta Cranzt) from the genetic diversity collection of CIAT (Cali, Colombia) were used to assess the diversity of cyanide contents in cassava leaves and roots (external peels and parenchyma). The cyanide concentration in leaves was determined in 11 genotypes at three different physiological ages. (3, 6 y 11 months). Analysis of the data by seven diversity groups corresponding to the centers of domestication of the genus Manihot in Latin America put in evidence significant differences in terms of cyanide contents in leaves, peels and parenchyma. In particular, the Amazon and Andean groups were associated with high cyanide and low cyanide contents, respectively. This study showed that peels and leaves have a major cyanide content than parenchyma. Furthermore, the cyanide concentration is higher in young leaves, as they mature the content of HCN decreases over time. These findings on cyanide content in a large number of genotypes and its relation with physiological age are important to identify genotypes with attractive attributes for increased utilization of cassava leaves.

Cassava leaves, usually considered a byproduct of the production of cassava roots, may offer a significant source of proteins, essential amino-acids and vitamins, with nutritional benefits for both human and animal consumption. A concern however is the risk of cyanide formation from cyanogenic glycosides, if leaves are insufficiently processed. 178 cassava genotypes (Manihot esculenta Cranzt) from the genetic diversity collection of CIAT (Cali, Colombia) were grown and harvested to assess the diversity of cyanide contents in cassava leaves and roots, and characterize their nutritional potential (carotens, proteins, essential amino-acids). The cyanide concentration in leaves was determined at three different physiological ages. The contents of cyanide and all-trans-β-carotene in cassava leaves ranged from 345 ppm to 7484 ppm DB and from 171 μg/g to 547 μg/g DB, respectively. Cassava leaves also showed significant levels of essential amino-acids valine, leucine, phenylalanine, and lysine, and average total protein content of 11% DB. Analysis of the data by seven diversity groups corresponding to the centers of domestication of the genus Manihot in Latin America put in evidence significant differences in terms of cyanide contents in leaves, peels and parenchyma. In particular the Amazon and Andean groups were associated with high cyanide and low cyanide contents, respectively.