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Impacto del ENOS sobre los rendimientos de maíz en la región pampeana argentina
Fernández Long,M. E.; Spescha,L.; Hurtado,R.; Murphy,G. M.;
Agriscientia , 2011,
Abstract: the “el ni？o southern oscillation” (enso) phenomenon is one of the main responsible factor for interannual climate variability in the “pampas” region. this work aims to analyze the impact of enso on the annual variations of corn production. the region was divided into 10 areas in which yields have a homogeneous interannual variability. five enso indexes were used the results indicated that, in most parts of the region, the deviations of trend line yields are, in general, positive during “el ni？o” events and negative during “la ni？a”. however, the impact is very strong in the north and centre of the analyzed region and weakens southward. in the southeast of the province of buenos aires, the behavior is different than the rest. averaging indexes from may to july we obtained a good indicator of the enso impact on maize production, providing valuable information to make decisions with enough anticipation for the crop year.
Impacto del ENOS sobre los rendimientos de maíz en la región pampeana argentina Impact of the ENSO on corn yields in the Argentinean pampas region
M. E. Fernández Long,L. Spescha,R. Hurtado,G. M. Murphy
Agriscientia , 2011,
Abstract: El fenómeno de “El Ni o - Oscilación del Sur” (ENOS) es uno de los principales responsables de la variabilidad climática interanual, con influencia sobre la región pampeana argentina. El objetivo de este trabajo fue analizar el impacto del ENOS sobre las variaciones anuales de la producción de maíz. La región fue dividida en 10 zonas en las cuales los rendimientos tienen una variabilidad interanual homogénea. Se utilizaron diferentes índices del ENOS. Los resultados indicaron que, en la mayor parte de la región, los desvíos de los rendimientos son, en general, positivos durante eventos “El Ni o” y negativos durante “La Ni a”. Sin embargo, el impacto es muy fuerte al norte y centro de la región analizada, y se debilita hacia el sur. En el sudeste de la provincia de Buenos Aires el comportamiento es diferente que en el resto. Los índices promediados de mayo a julio son, en general, un buen indicador de la influencia del ENOS sobre la productividad de los cultivos, y brindan una adecuada información para la toma de decisiones de la empresa agropecuaria, con suficiente anticipación respecto del comienzo de la campa a. The “El Ni o Southern Oscillation” (ENSO) phenomenon is one of the main responsible factor for interannual climate variability in the “pampas” region. This work aims to analyze the impact of ENSO on the annual variations of corn production. The region was divided into 10 areas in which yields have a homogeneous interannual variability. Five ENSO indexes were used The results indicated that, in most parts of the region, the deviations of trend line yields are, in general, positive during “El Ni o” events and negative during “La Ni a”. However, the impact is very strong in the North and Centre of the analyzed region and weakens southward. In the southeast of the province of Buenos Aires, the behavior is different than the rest. Averaging indexes from May to July we obtained a good indicator of the ENSO impact on maize production, providing valuable information to make decisions with enough anticipation for the crop year.
Natural and laser-induced cavitation in corn stems: On the mechanisms of acoustic emissions
E. Fernández,R. J. Fernández,G. M. Bilmes
Physics , 2012, DOI: 10.4279/PIP.040003
Abstract: Water in plant xylem is often superheated, and therefore in a meta-stable state. Under certain conditions, it may suddenly turn from the liquid to the vapor state. This cavitation process produces acoustic emissions. We report the measurement of ultrasonic acoustic emissions (UAE) produced by natural and induced cavitation in corn stems. We induced cavitation and UAE in vivo, in well controlled and reproducible experiments, by irradiating the bare stem of the plants with a continuous-wave laser beam. By tracing the source of UAE, we were able to detect absorption and frequency filtering of the UAE propagating through the stem. This technique allows the unique possibility of studying localized embolism of plant conduits, and thus to test hypotheses on the hydraulic architecture of plants. Based on our results, we postulate that the source of UAE is a transient "cavity oscillation" triggered by the disruptive effect of cavitation inception.
Mix design of steel fiber reinforced concrete
Moreno, E.,Fernández Cánovas, M.
Materiales de Construccion , 1997,
Abstract: Mix design of steel fiber reinforced concrete (SFRC) is concerned with achieving a workability, homogeneity, durability and strength suitable for its use. Variables defining any mix design of SFRC are commented below, as well as their influence on some properties of fresh and hardened SFRC. A special attention is paid to concrete, since it's the main use of steel fibers in Spain now, followed by paving construction. El objetivo de una correcta dosificación de hormigón reforzado con fibras metálicas (HRFA) es conseguir una mezcla que mantenga una docilidad, homogeneidad, durabilidad y resistencia adecuadas a su uso. A continuación se estudian las variables que definen una dosificación de HRFA, así como su influencia en las propiedades del HRFA fresco y endurecido. Se presta una especial atención al hormigón proyectado ya que es la principal aplicación de las fibras metálicas en Espa a, seguido por la construcción de pavimentos.
The role of the lexical status and the frequency of the prime on the unrelated condition using the technique of the masking of the prime.
M. Perea,L. Fernández,E. Rosa
Psicológica , 1998,
Abstract:
Variabilidad diagnóstico-terapéutica en ni os con un primer episodio disneizante Diagnostic-therapeutic variability in children with a first wheezing episode
E.M. Fernández Fernández,M. Fernández Díaz,J.M. Fernández Menéndez,C. Suárez Casta？ón
Boletín de Pediatría , 2009,
Abstract: Introducción: el diagnóstico de los episodios sibilantes del lactante es fundamentalmente clínico. Las claves del tratamiento son la oxigenación y la hidroterapia, siendo la utilización de fármacos polémica. Objetivo: conocer la variabilidad del enfoque diagnóstico-terapéutico de los primeros episodios sibilantes del lactante en nuestro medio. Material y métodos: se dise ó un estudio prospectivo observacional. Se incluyeron, durante 12 meses, a ni os menores de 2 a os, ingresados en nuestro hospital por un primer episodio disneizante. Se recogieron datos sobre pruebas complementarias, tratamiento durante el ingreso y al alta. Se realizó una estadística descriptiva y posteriormente una comparación por grupos, virus sincitial respiratorio (VSR) positivo vs VSR negativo y menores de 6 meses vs mayores de 6 meses. Resultados: La detección del antígeno VSR en exudado nasofaríngeo fue solicitada en el 83% de los pacientes, radiografía de tórax en el 67% y analítica de sangre en el 46%. El salbutamol, seguido de los corticoides orales fueron los fármacos más utilizados. La adrenalina fue más utilizada en el grupo VSR positivo (24,5% vs 11,1%; p< 0,05). Los corticoides en el grupo de los mayores de 6 meses (67,7% vs 22,9%; p<0,001) y la adrenalina en los menores de 6 meses (22,9% vs 1,4%; p<0,01). Conclusiones: Se solicitan pruebas complementarias a un alto porcentaje de pacientes. La adrenalina se utiliza fundamentalmente en ni os VSR positivos y menores de 6 meses y los corticoides orales en ni os mayores de esta edad. Introduction: Diagnosis of wheezing syndromes is usually made on clinical grounds. Oxygen therapy and hydration are the mainstay of treatment while drug therapy is controversial. Objective: to assess the variability in the diagnostic and therapeutic approach to infants with a first episode of wheezing at a single institution. Subjects and methods: Prospective observational study. Infants younger than 2 years admitted to our hospital in a 12-month period for a first episode of wheezing were included. Data on laboratory and radiological studies, hospital treatment and treatment at discharge were collected. A descriptive analysis and a comparison among groups, Respiratory syncitial virus (RSV) positive vs RSV negative, and younger vs older than 6 months, were performed. Results: Virologic tests for RSV were performed in 83% of the cases, radiological studies in 67% and blood was drawn for analysis in 46%. Salbutamol, followed by oral corticosteroids, were the drug therapies most commonly used. Epinephrine was used more frequently in RSV-positive i
Recubrimiento de Stellite 6 sobre acero inoxidable realizado con láser de CO2 para válvulas de escape de motores diesel
Cadenas, M.,Cuetos, J. M.,Fernández, J. E.,Fernández, M. R.
Revista de Metalurgia , 2002,
Abstract: To reduce the recovery or the replacement costs of diesel engine exhaust valves, they are manufactured with an economic base material, and a coating which is deposited on the seat valve in order to reach high hardness and good impact, corrosion and high temperature wear resistance (>550 °C) and without lubrication. In this work, appropriate laser cladding parameters have been determined to obtain Stellite 6 coatings over AISI 304 steel (as plane test specimens) and SAE EV8 steel (as valves) substrates. One and two superimposed tracks were deposited on the seat valves, and modifying the laser power as a function of the rotated angle at the beginning and the end of the circular tracks, pores and cracks have been minimized and the thickness of the track were made uniform. Hardness, dilution and final microstructure of the different coatings have been analysed. A 10 % dilution and 550 HV in the tracks over plane test specimens was observed, while valves with one track showed 25 % and 430 HV respectively. With two superimposed tracks the hardness was up to 470 HV in the upper track. Para abaratar el coste de recuperación o sustitución de válvulas de escape en motores diesel, estas se fabrican con un material base económico, recubriéndose el asiento de la válvula con otro material al que se exigirá elevada dureza y buena resistencia al impacto, a la corrosión y al desgaste erosivo en caliente (>550 °C) y sin lubricación. Partiendo de esta idea, en el presente trabajo se han determinado los parámetros adecuados para realizar, mediante la técnica de plaqueado láser, un recubrimiento con Stellite 6, sobre sustratos de acero AISI 304 (probetas planas) y SAE EV8 (válvulas reales). Sobre las válvulas, se depositaron uno y dos cordones superpuestos, se minimizó la presencia de poros y grietas, modificando el grado de solape inicial y final de los cordones circulares y la potencia en función del ángulo girado. Así, se consiguieron cordones de espesor uniforme. Tras los tratamientos, se estudiaron la dureza, dilución y microestructura final de los distintos recubrimientos, observándose, en los cordones sobre probetas planas, diluciones del 10 % y durezas de 550 HV, mientras que, en las válvulas con un cordón, eran del 25 % y 430 HV, respectivamente. Con dos cordones superpuestos, la dureza llegaba a 470 HV en el cordón superior.
Herpesvirus equino 2: estudio de la relación entre excreción viral y enfermedad respiratoria en equinos deportivos pura sangre de carrera
Craig,M. I.; Barrandeguy,M. E.; Fernández,F. M.;
Revista argentina de microbiolog？-a , 2006,
Abstract: equine herpesvirus 2 (ehv-2) was isolated from healthy animals; therefore, the association between ehv-2 infection and respiratory disease raises the question of the role of this agent in this pathology. to date, there are no reports that relate viral excretion to health, this study then analysed 153 nasal swabs from horses in different age groups (older and younger than 1 year old) and state of health (clinically healthy and with respiratory symptoms). results showed that the percentage of horses with viral excretion was higher within the clinically healthy group, being significative (p<0.05) in the younger than 1 year old group, whereas the percentage of animals with respiratory symptoms did not show significant differences (p> 0.05) between age groups.
Herpesvirus equino 2: estudio de la relación entre excreción viral y enfermedad respiratoria en equinos deportivos pura sangre de carrera Equine herpesvirus 2: A study on the relation between viral excretion and respiratory disease in thoroughbred horses
M. I. Craig,M. E. Barrandeguy,F. M. Fernández
Revista argentina de microbiolog？-a , 2006,
Abstract: La asociación entre infección por herpesvirus equino 2 (HVE-2) y enfermedad respiratoria en los equinos plantea un interrogante acerca del verdadero papel del virus como agente causal de la enfermedad, debido a que este virus también ha sido detectado en animales asintomáticos. Hasta el momento, no existen datos precisos que permitan establecer una relación clara entre la excreción viral y el estado clínico de los animales. En este trabajo se analizaron 153 muestras de hisopado nasal provenientes de animales de diferentes grupos etarios (menores y mayores de 1 a o) y estado clínico (con enfermedad respiratoria y asintomáticos). Los resultados mostraron que el mayor porcentaje de individuos con excreción viral pertenecían al grupo de animales asintomáticos, y que este porcentaje era significativamente (p<0,05) más importante en los menores de 1 a o. Por otra parte, los porcentajes en la excreción viral de los animales con sintomatología clínica no fueron significativamente distintos (p>0,05) al comparar los dos grupos etarios entre sí. Equine herpesvirus 2 (EHV-2) was isolated from healthy animals; therefore, the association between EHV-2 infection and respiratory disease raises the question of the role of this agent in this pathology. To date, there are no reports that relate viral excretion to health, this study then analysed 153 nasal swabs from horses in different age groups (older and younger than 1 year old) and state of health (clinically healthy and with respiratory symptoms). Results showed that the percentage of horses with viral excretion was higher within the clinically healthy group, being significative (p<0.05) in the younger than 1 year old group, whereas the percentage of animals with respiratory symptoms did not show significant differences (p> 0.05) between age groups.
Toxinas de Clostridium perfringens
Morris,W. E.; Fernández-Miyakawa,M. E.;
Revista argentina de microbiolog？-a , 2009,
Abstract: clostridium perfringens is an anaerobic gram-positive spore-forming bacillus. it is one of the pathogens with larger distribution in the environment; it can be isolated from soil and water samples, which also belongs to the intestinal flora of animals and humans. however, on some occasions it can act as an opportunistic pathogen, causing diseases such as gas gangrene, enterotoxemia in sheep and goats and lamb dysentery, among others. in human beings, it is associated to diseases such as food poisoning, necrotic enterocolitis of the infant and necrotic enteritis or pigbel in papua-new guinea tribes. the renewed interest existing nowadays in the study of c. perfringens as a veterinarian and human pathogen, together with the advance of molecular biology, had enabled science to have deeper knowledge of the biology and pathology of these bacteria. in this review, we discuss and update the principal aspects of c. perfringens intestinal pathology, in terms of the toxins with major medical relevance at present.
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