Field host range of Apanteles opuntiarum (Hymenoptera: Braconidae) in Argentina, a potential biocontrol agent of Cactoblastis cactorum (Lepidoptera: Pyralidae) in North America

Field exploration in Argentina for cactophagous lepidopteran hosts parasitized by the recently described braconid parasitoid Apanteles opuntiarum Martínez & Berta (Hymenoptera: Braconidae) revealed a host range restricted to Cactoblastis cactorum (Berg) (Lepidoptera: Pyralidae) and C. doddi. Field collections of cactophagous larvae parasitized by the congeneric and sympatric parasitoid A. alexanderi included the host species C. bucyrus, Sigelgaita nr. chilensis, Tucumania sp., Tucumania tapiacola and Salambona sp. If a narrow host range for A.opuntiarum is confirmed in quarantine with North American cactus-feeding species, then this parasitoid could be released as a biological control agent for C. cactorum with little or no risk to non-target species.Las exploraciones de campo en Argentina de larvas hospedadoras cactófagas parasitadas por Apanteles opuntiarum Martínez & Berta (Hymenoptera: Braconidae), un bracónido recientemente descripto, revelaron un espectro de hospedadores restringido a Cactoblastis cac­torum (Berg) (Lepidoptera: Pyralidae) y C. doddi. Las colecciones de campo de larvas cactófagas parasitadas por la especie congenérica y simpátrica A. alexanderi identificaron a C. bucyrus, Sigelgaita nr. chi­lensis, Tucumania sp., Tucumania tapiacola y Salambona sp. como es­pecies hospedadoras. Si se confirma en cuarentena el estrecho rango de hospedadores de A. opuntiarum sobre especies norteamericanas que se alimentan de cactus, podría ser liberado como agente de con­trol biológico de C. cactorum, con bajo riesgo o ninguno a especies no blanco.Fil: Varone, Laura. Fundación para el Estudio de Especies Invasivas; ArgentinaFil: Logarzo, Guillermo Alejandro. Fundación para el Estudio de Especies Invasivas; ArgentinaFil: Martinez, Juan Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales ; ArgentinaFil: Navarro, Fernando. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto Superior de Entomología; ArgentinaFil: Carpenter, James E.. United States Department of Agriculture; Estados UnidosFil: Hight, Stephen D.. United States Department of Agriculture; Estados Unido

Geographical Range and Laboratory Studies on Apanteles opuntiarum (Hymenoptera: Braconidae) in Argentina, a Candidate for Biological Control of Cactoblastis cactorum (Lepidoptera: Pyralidae) in North America

La polilla de la tuna, Cactoblastis cactorum (Berg) (Lepidoptera: Pyralidae), es una plaga que amenaza las Opuntia spp. nativas de América del Norte. Se han implementado varias estrategias para su control, erradicándola de México pero no de los Estados Unidos, donde ha continuado incrementando su distribución geográfica con éxito. Por lo tanto, se propone un enfoque integrado que incluya al control biológico para regular las poblaciones de C. cactorum en América del Norte. Se realizaron relevamientos de campo del parasitoide recientemente descrito, Apanteles opuntiarum Martínez & Berta, dentro del área de distribución nativa de C. cactorum en Argentina, y se realizaron estudios de laboratorio para desarrollar un protocolo de cría del parasitoide. Apanteles opuntiarum fue el parasitoide más común de C. cactorum y sus distribuciones en el campo coincidieron ampliamente. En el laboratorio, el éxito reproductivo del parasitoide se maximizó cuando una o dos avispas estuvieron expuestas a 30 larvas dentro de un recipiente de 500 ml. Hembras criadas en laboratorio fueron menos exitosas parasitando hospedadores que hembras provenientes del campo. A pesar del éxito logrado en la cría de los parasitoides, obtuvimos una proporción de sexos sesgada hacia machos en los experimentos. Como este sesgo podría estar relacionado a la presencia del parásito reproductivo Wolbachia, tanto la colonia de laboratorio como individuos provenientes del campo fueron analizados y poseían Wolbachia. El presente estudio proporcionó información útil de campo y laboratorio para (1) estandarizar una técnica de cría en laboratorio; (2) realizar estudios de especificidad de hospedadores en condiciones de cuarentena; y (3) seleccionar las poblaciones de parasitoides que mejor coinciden con el clima de las áreas invadidas por C. cactorum en América del Norte.The cactus moth, Cactoblastis cactorum (Berg) (Lepidoptera: Pyralidae), is a pest that threatens native Opuntia spp. in North America. Control tactics developed and implemented against this invasive pest successfully eradicated the moth in Mexico and on barrier islands in the United States. However, with the cancellation of the regional management program in the United States, no control tactics are being implemented to mitigate the expansion of the moth's geographical range. Hence, an integrated approach including biological control is proposed to regulate the population of C. cactorum in North America. Field surveys of the recently described parasitoid, Apanteles opuntiarum Martínez & Berta, were carried out within the C. cactorum native range in Argentina, and laboratory studies were conducted to develop a parasitoid rearing protocol. Apanteles opuntiarum was the most common parasitoid of C. cactorum and their field distributions were similar. In the laboratory, the parasitoid's reproductive success was maximized when one or two female wasps were exposed to 30 host larvae within a 500 ml container. Laboratory reared females were less successful at parasitizing hosts than field collected females. In spite of the success achieved with laboratory rearing, male bias was observed throughout the experiments. Because this bias might be related to the presence of the reproductive parasite Wolbachia, both laboratory colony and field collected individuals were screened and Wolbachia was detected. This study provides useful field and laboratory information on (1) laboratory rearing techniques for A. opuntiarum; (2) developing host specificity test protocols for studies under quarantine conditions; and (3) selecting parasitoid populations that best match the climatic conditions present in the C. cactorum invaded areas of North America.Fil: Mengoni Goñalons, Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Varone, Laura. Fundación para el Estudio de Especies Invasivas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Logarzo, Guillermo Alejandro. Fundación para el Estudio de Especies Invasivas; ArgentinaFil: Guala, Mariel. Fundación para el Estudio de Especies Invasivas; ArgentinaFil: Rodriguero, Marcela Silvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Hight, Stephen D.. United States Department Of Agriculture. Agriculture Research Service; Estados UnidosFil: Carpenter, James E.. United States Department Of Agriculture. Agriculture Research Service; Estados Unido

Laser pulse effects on plasma-sprayed and bulk tungsten

Tungsten (W) is considered a promising plasma-facing material for protecting the divertor of the ITER (International Thermonuclear Experimental Reactor). The effects on W of transient thermal loads of high energy occurring in a tokamak under operative conditions have been simulated through a single laser pulse delivered by an Nd:YAG laser. Bulk and plasma-sprayed (PS) samples have been submitted to tests and successively examined via SEM (scanning electron microscopy) observations. In both types of materials, the laser pulse induces similar effects: (i) a crater forms in the spot central area; (ii) all around the area, the ejection and the movement of molten metal give rise to a ridge; (iii) in a more external area, the surface shows plates with jagged boundaries and cracks induced by thermal stresses; (iv) the pores present in the original material become preferred ablation sites. However, the affected surface area in PS samples is larger and asymmetric if compared to that of bulk material. Such a difference has been explained by considering how microstructural characteristics influence heat propagation from the irradiated spot, and it was found that grain size and shape play a decisive role

photochemical performance of carpobrotus edulis in response to various substrate salt concentrations

Abstract Substrate salinity is one of the main abiotic factors limiting plant establishment, growth and distribution in coastal habitats. Nevertheless, few studies have investigated the interaction between salt concentration and duration of exposure on the physiology and growth of Carpobrotus edulis, an important invasive plant species growing in coastal dune habitats. In this study, four salinity treatment cycles of different length (three, six, twelve and twenty-four days) at salinity of 0 M, 0.1 M, 0.2 M and 0.3 M were imposed. A significant response in plant growth was elicited after 24 days of treatment. The main shoot length (MSL) and stem biomass (SBMS) increased by 11% and 4%, respectively at 0.1 M and by 25% and 6% at 0.2 M compared with the control. At 0.3 M MSL did not significantly differ from the control while SBMS was 18% lower. Moreover, C. edulis showed a high photoprotection mechanism efficiency resulting in a high carotenoid to chlorophyll ratio increase which was two, three and four times higher than the control at 0.1 M, 0.2 M and 0.3 M, respectively. Photochemically, the quantum yield of photosynthesis (ΦPSII) was 17%, 50% and 52% lower than the control at 0.1 M, 0.2 M and 0.3 M. The ΦPSII decrease was associated with a low leaf nitrogen content (NL) decrease (16%, 21% lower than the control at 0.1 M and 0.2 M, respectively). By contrast, NL had the highest decrease (41% lower than the control) at 0.3 M, which constrains the growth capacity. Overall, C. edulis was able to modulate its response to salinity. The salt stimulated shoot elongation at low or moderate salt concentrations could confer a competitive advantage making C. edulis even more efficient in establishing within the areas which it colonizes. Since the expansion of C. edulis may be enhanced by the forecasted increase in soil salinity, it will be of paramount importance to apply effective management practices in areas invaded by C. edulis to limit its expansion and preserve the native plant biodiversity

Zn–al layered double hydroxides synthesized on aluminum foams for fluoride removal from water

Fluoride excess in water represents an environmental issue and a risk for human health since it can cause several diseases, such as fluorosis, osteoporosis, and damage of the nervous system. Layered double hydroxides (LDHs) can be exploited to remove this contaminant from water by taking advantage of their high ion-exchange capability. LDHs are generally mixed with polluted water in the form of powders, which then cause the problem of uneasy separation of the contaminated LDH sludge from the purified liquid. In this work, Zn–Al LDH films were directly grown in situ on aluminum foams that acted both as the reactant and substrate. This method enabled the removal of fluoride ions by simple immersion, with ensuing withdrawal of the foam from the de-contaminated water. Different LDH synthesis methods and aluminum foam types were investigated to improve the adsorption process. The contact time, initial fluoride concentration, adsorbent dosage, and pH were studied as the parameters that affect the fluoride adsorption capacity and efficiency. The highest absorption efficiency of approximately 70% was obtained by using two separate growth methods after four hours, and it effectively reduced the fluoride concentration from 3 mg/L to 1.1 mg/L, which is below the threshold value set by WHO for drinking water

UN EJEMPLO DE INTEGRACIÓN REGIONAL Movilidad e Intercambio

Las Universidades Nacionales del NOA, desde las Unidades Académicas que ofrecen carreras de Ingeniería, elaboraron propuestas con el objeto de promover la constitución de ámbitos de reflexión y planificación sobre articulación y flexibilización de planes de estudios, en vista a la integración del sistema de Educación Superior; logrando: diseñar un Ciclo Común Articulado (CCA) para la familia de Carreras de Ingeniería, ejecutar acciones para su efectiva puesta en marcha y, dar a conocer a otras Universidades Nacionales promoviendo su incorporación en ellas. De este modo, se buscó favorecer la movilidad de estudiantes entre las Universidades participantes y estimular el desarrollo de innovaciones académicas y de gestión, potenciando las fortalezas que poseen. El diseño, adecuado a veintidós carreras, ha sido organizado a partir de áreas curriculares con contenidos y bibliografía básica comunes y rangos de cargas horarias. Este proceso innovador e inédito para la región, ha necesitado del desarrollo de normativas específicas para garantizar que los estudios realizados por los alumnos en otra Universidad del consorcio, tenga un reconocimiento académico en la Universidad receptora, ha permitido impulsar modelos y ha favorecido la participación en los ciclos generales de conocimientos básicos con actividades que serían mejoradas con el uso de las NTIyCs.

Sanitation: a set of interventions mandated by the Italian government to limit the spread of SARS-CoV-2 in non-medical facilities

There have been several concerns about the environmental persistence of SARS-CoV-2 virus. These concerns led to the formulation of sanitation measures that try to lower the risk of indirect transmission of SARS-CoV-2 in non-medical facilities. This manuscript will elucidate the topic of environmental persistence of SARS-CoV-2. This will benefit the occupational health professionals two-fold. It describes the proper techniques for an effective sanitation of the workplace. It also explains how to protect workers who are responsible for carrying out these interventions. Sanitation is an important measure for a safe workplace. Sanitation is legally established and referenced by all the decrees so far enacted by the Italian government. It is defined as a set of actions and procedures that aim to lower the risk of indirect transmission of SARS-CoV-2 virus

Cr segregation and impact fracture in a martensitic stainless steel

The fracture surfaces of a 10.5 wt.% Cr martensitic stainless steel broken in Charpy tests have been investigated through X-ray photoelectron spectroscopy (XPS). The specimens have been examined in two different conditions: as-quenched and heat treated for 10 h at 700°C. The trends of Fe/Cr ratio vs. test temperature are similar to the sigmoidal curves of absorbed energy and, after both ductile and quasi-cleavage brittle fractures, such ratio is always significantly lower than the nominal value of the steel chemical composition. Cr segregation does not occur on a macroscopic scale but takes place in microscopic zones which represent weaker spots in the steel matrix and a preferred path for moving cracks. Small area (diameter 300 μm) XPS measurements evidenced a higher density of such microscopic zones in the inner part of probes; this is explained by the different diffusion length of Cr atoms in the external and inner parts during quenching from austenitic field which has been calculated through FEM simulations. No significant differences of Cr concentration were observed in fracture surfaces of probes with and without heat treatment. The results highlight how Cr segregation plays a role not only in the intergranular mode of fracture but also in the quasi-cleavage and ductile ones

Estrategias metodológicas para desarrollar la compresión lectora en los estudiantes de cuarto grado, de la escuela Rafaela Herrera, del departamento de Granada, municipio de Diriomo durante los meses de Enero-Abril 2019

El presente trabajo de investigación es un estudio descriptivo –interpretativo de las estrategias metodológicas para desarrollar la comprensión lectora en los niños y niñas de Cuarto Grado del Colegio Público Rafaela Herrera, ubicado en el municipio de Diriomo, del Departamento de Granada, durante el primer periodo evaluativo del año 2019. Para llevar a cabo este estudio, el equipo de investigación abordo las estrategias aplicadas por la docente y los niveles de comprensión lectora que poseen los estudiantes, se evaluaron los diferentes datos obtenidos mediante la aplicación de instrumentos y finalmente se identificó la causa del problema estudiado. Esta investigación se trabajó bajo un enfoque cualitativo, porque a través de este ha sido posible la captación descriptiva de datos vinculados con los procesos psíquicos, actividades explicitas protagonizadas por miembros activos inmersos en un ambiente social que indudablemente incide en la dimensión psicoactiva de cada persona perteneciente al escenario de investigación. Para tal captación se usaron instrumentos tales como: guía de entrevista a subdirectora, docente y estudiantes, prueba diagnóstica a estos últimos y guía de observación de clases. Entre los principales hallazgos podemos mencionar que la docente aplica pasos de comprensión lectora, como lo son: Lectura silenciosa por el alumno. Lectura oral. Lectura dirigida por los alumnos. Vocabulario desconocido por contexto y uso del diccionario En cuanto a los niveles de comprensión lectora que poseen los estudiantes de cuarto grado han alcanzado el nivel literal de comprensión lectora en su mayoría, y el nivel inferencial en su minoría. Actualmente no han logrado llegar al nivel crítico, según resultados de la prueba diagnóstica. Entre las dificultades que presentan los estudiantes en el desarrollo de la comprensión lectora se encuentran Decodificación poco satisfactoria Irrespeto a los signos de puntuación Limitación de vocabulario Hábito nulo de lectura Poca capacidad para resumir textos Lectura Silábica Comprensión nula o parcial del texto Timidez en la participación de la lectura Con base en los resultados, se elaboraron recomendaciones dirigidas al uso de estrategias metodológicas funcionales, tanto para el grupo estudiantil como para la docente implicada en el fenómeno estudiad