283 research outputs found

    Flow of low viscosity Boger fluids through a microfluidic hyperbolic contraction

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    In this work we focus on the development of low viscosity Boger fluids and assess their elasticity analyzing the flow through a microfluidic hyperbolic contraction. Rheological tests in shear and extensional flows were carried out in order to evaluate the effect of the addition of a salt (NaCl) to dilute aqueous solutions of polyacrylamide at 400, 250, 125 and 50 ppm (w/w). The rheological data showed that when 1% (w/w) of NaCl was added, a significant decrease of the shear viscosity curve was observed, and a nearly constant shear viscosity was found for a wide range of shear rates, indicating Boger fluid behavior. The relaxation times, measured using a capillary break-up extensional rheometer (CaBER), decreased for lower polymer concentrations, and with the addition of NaCl. Visualizations of these Boger fluids flowing through a planar microfluidic geometry containing a hyperbolic contraction, which promotes a nearly uniform extension rate at the centerline of the geometry, was important to corroborate their degree of elasticity. Additionally, the quantification of the vortex growth upstream of the hyperbolic contraction was used with good accuracy and reproducibility to assess the relaxation time for the less concentrated Boger fluids, for which CaBER measurements are difficult to perform

    Effect Of Soil Management On The White Grub Population And Damage In Soybean

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    To evaluate the effect of soil management systems on population of white grubs, (Phyllophaga cuyabana Moser), and on its damage in soybean, experiments were set up under no-tillage and conventional tillage (one disk plow, and a leveling disk harrow) areas. Primary tillage equipment, used in other soil management systems, such as moldboard plow, disk plow, chisel plow and heavy duty disk harrow were also tested. Fluctuation of P. cuyabana population and the extent of its damage to soybean was similar under no-tillage and conventional tillage systems. Results comparing a range of primary tillage equipment showed that it affected soil insect populations differently, depending on the time during the season in which tillage was executed. Larval mortality could mostly be attributed to their exposure to adverse factors, soon after tillage, than to changes in soil conditions. Reduction of white grub population was more evident in plots managed by heavier equipment, such as the moldboard plow. Soil tillage could be one component within the soil pest management system in soybean, however, its use can not be generalized.355887894Alvarado, L., (1979) Comparación Poblacional de "Gusanos Blancos" (Larvas de Coléopteros Scarabaeidae) en Tres Situaciones de Manejo, 5p. , Pergamino : INTA/ EERA, (INTA/EERA. Genéralidades Carpeta de Producción Vegetal. Información, 16)Brown, W.R., Gange, A.C., Insect herbivore below ground (1990) Advances in Ecological Research, 20, pp. 1-58. , San DiegoGarcia, M.A., Arthropods in tropical corn field: Effects of woods and insecticides on community composition (1991) Plant-animal Interactions: Evolutionary Ecology in Tropical and Temperate Regions, pp. 619-634. , PRICE, P.LEWINSOHON, T.M.FERNANDES, W.BENSON, W.W. (Eds.). New York: J. WileyGassen, D.N., Corós associados ao sistema de plantio direto (1993) Plantio Direto no Brasil, pp. 141-149. , ALDEIA NORTE (Passo Fundo, RS) (Ed.). Passo Fundo : Embrapa-CNPT/Fundacep Fecotrigo/Fundação ABCHammond, R.B., Stinner, B.R., Seedcom maggots (Diptera: Anthomyiidae) and slugs in conservation tillage systems in Ohio (1987) Journal of Economic Entomology, 80, pp. 680-684. , LanhamHoffmann-Campo, C.B., Parra, J.R.P., Mazzarin, R.M., Ciclo biológico de Sternechus subsignatus Boheman, 1836 (Coleoptera: Curculionidae) em soja no norte do Paraná (1991) Revista Brasileira de Biologia, 51, pp. 615-621. , Rio de Janeiro(1976) Manual Agropecuário para O Paraná, 1. , LondrinaOliveira, L.J., (1997) Ecologla Comportamental e de Interações com Plantas Hospedeiras em Phyllophaga Cuyabana (Moser) (Coleoptera: Melolonthidae, Melolonthinae) e Implicações para o Seu Manejo em Cultura de Soja, 148p. , Campinas : Unicamp, Tese de DoutoradoOliveira, L.J., Hoffmann-Campo, C.B., Do Amaral, M.L.B., Nachi, C., (1992) Coró Pequeno da Soja, 4p. , Londrina : Embrapa-CNPSo. (Embrapa-CNPSo. Documentos, 51)Oliveira, L.J., Hoffmann-Campo, C.B., Sistemas de preparo de solo: Efeito sobre populações de larvas de escarabeídeos e Sternechus subsignatus (1996) Resultados de Pesqulsa de Soja 1990/91, pp. 464-468. , EMBRAPA. Centro National de Pesquisa de Soja (Londrina, PR). Londrina, (Embrapa-CNPSo. Documentos, 99)Rincón, M.B.N., Tiscareño, M., Velásquez, M., Diversidad y abundancia de Melolonthidae y Scarabaeidae (Insecta: Coleoptera) asociados a diferentes sistemas de labranza y porcentajes de cobertura vegetal en agrosistemas de maíz del Estado de Michoacan, México (1997) Reunión Latino-americana de Escara-beidologia, 3, pp. 18-19. , Xalapa. Memórias. Xalapa: Institute de Ecologia, 1997Shelton, M.D., Edwards, C.R., Effects of weeds on the diversity and abundance of insects on soybeans (1983) Environmental Entomology, 12, pp. 296-298. , LanhamDa Silva, M.T.B., Grutzmacher, A.D., Ruedell, J., Link, D., Costa, E.C., Influência de sistemas de manejo de suelos y de culturas sobre insectos sub́terraneos (1994) Clência Rural, 24, pp. 247-251. , Santa MariaDa Silva, M.T.B., Klein, V.A., Efeito de diferentes métodos de preparo do solo na infestação e danos de Sternechus subsignatus (Boheman) em soja (1997) Ciência Rural, 27, pp. 533-536. , Santa MariaDa Silva, M.T.B., Klein, V.A., Link, D., Reinert, D.J., Influência de sistemas de manejo de solos na oviposição de Diloboderus abderus Sturm (Coleoptera: Melolonthidae) (1994) Anais da Sociedade Entomológica Brasileira, 3, pp. 543-548. , LondrinaSloderbeck, P.E., Yeargen, K.V., Green cloverworm (Lepidoptera: Noctuidae) populations in conventional and double-cropped, no-till soybeans (1983) Journal of Economic Entomology, 76, pp. 785-791. , LanhamSmith, A.W., Hammond, R.B., Stinner, B.R., Influence of rye-cover crop management on soybean foliage arthropods (1988) Environmental Entomology, 17, pp. 109-114. , LanhamStinner, B.R., House, G.J., Arthropods and other invertebrates in conservation-tillage agriculture (1990) Annual Review of Entomology, 35, pp. 299-318. , Palo AltoStrnad, S.P., Bergman, M.K., Movement of first-instar western corn rootworms (Coleoptera: Chrysomelidae) in soil (1987) Environmental Entomology, 16, pp. 975-978. , LanhamToxclair Jr., N.N., Boethel, D.J., The influence of tillage practices and row spacing on soybean insect populations in Louisiana (1984) Journal of Economic Entomology, 77, pp. 1571-1579. , LanhamWinter, J.P., Voroney, R.P., Ainsworth, D.A., Soil microarthropods in long-term no-tillage and conventional tillage corn production (1990) Canadian Journal of Soil Science, 70, pp. 641-653. , Ottaw

    Tachyon warm inflationary universe model in the weak dissipative regime

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    Warm inflationary universe model in a tachyon field theory is studied in the weak dissipative regime. We develop our model for an exponential potential and the dissipation parameter Γ=Γ0\Gamma=\Gamma_0=constant. We describe scalar and tensor perturbations for this scenario.Comment: 9 pages, accepted by European Physical Journal

    Feeding, Muscle and Packaging Effects on Meat Quality and Consumer Acceptability of Avileña-Negra Ibérica Beef

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    In order to achieve an attractive and differentiated product for the consumer and to optimize and to maximize profitability for the farmers within the EU Protected Geographical Indication "Carne de Ávila", 24 yearling males of Avileña-Negra Ibérica breed were used to evaluate the effect of 2 feeding systems, concentrate (CON) and maize silage (SIL), and 2 packaging systems, vacuum (VAC) and modified atmosphere (MAP), on fatty acid composition, proximate analysis, water holding capacity and consumer acceptability of meat in 2 muscles: Longissimus thoracis (LT) and Semitendinosus (ST). Animals fed with concentrate showed higher carcass weight. However, feeding did not affect the proximate analysis of the meat. The use of maize silage improved the amount of conjugated linoleic acid and n-3 polyunsaturated fatty acids (PUFA) and the relation n-6 PUFA/n-3 PUFA. In LT muscle, feeding influenced texture, samples from SIL being more tender. The VAC packaging showed higher cooking losses than MAP in both muscles. Aging increased tenderness and cooking losses but decreased thawing losses. LT samples from SIL feeding were better accepted by consumers and VAC packaging showed higher scores than MAP. We can conclude that the use of maize silage could be an alternative feeding for this type of animals improving some aspects of the quality of the meat

    Estudio de viabilidad económica de la implantación de bioceldas en una planta de tratamiento de aguas residuales

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    Las aguas residuales generadas en la industria de los zumos se caracterizan entre otras cosas por presentar altas concentraciones de materia orgánica, la cual es muy costosa de eliminar con los tratamientos que existen actualmente.En los últimos años están surgiendo numerosos estudios en torno al uso de celdas de combustible microbiológicas o bioceldas como método de tratamiento de aguas residuales. En este artículo se ha realizado un estudio de viabilidad económica de la implantación de 10 bioceldas para tratar las aguas residuales generadas en una industria de este tipo. Para ello, se analizaron tres posibles escenarios que podrían darse utilizando estos sistemas y se compararon los resultados obtenidos con el uso de un reactor convencional de fangos activos. Los resultados obtenidos para el VAN mostraron que la utilizaciónde bioceldas podría proporcionar un ahorro comprendido entre un 10 y 20 % aproximadamente dependiendo de si es un escenario pesimista u optimista, respectivamente, teniendo en cuenta un tiempo de vida de la planta de 15 años. El área de electrodo por celda considerada en este estudio fue de 0,36 m2, la cual dio lugar a densidades de potencia algo más altas que las encontradas en la bibliografía. Por ello, se decidió realizar un análisis de sensibilidad considerando áreas de electrodo de 0,5 m2 y 0,8 m2 en las bioceldas. Se encontró que aún utilizandoáreas de 0,5 m2 el VAN seguiría siendo positivo en todos los escenarios considerados y para el valor de 0,8 m2 se obtuvieron también resultados favorables en el escenario optimista. Estos resultados muestran que siempre que se cumplan los criterios establecidos en este estudio, la depuración mediante bioceldas en una industria de este tipo podría ser una alternativa más rentable que la depuración convencional mediante fangos activos

    Gene therapy in the management of oral cancer: Review of the literature

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    Gene therapy essentially consists of introducing specific genetic material into target cells without producing toxic effects on surrounding tissue. Advances over recent decades in the surgical, radiotherapeutic and chemotherapeutic treatment of oral cancer patients have not produced a significant improvement in patient survival. Increasing interest is being shown in developing novel therapies to reverse oral epithelial dysplastic lesions. This review provides an update on transfer techniques, therapeutic strategies, and the clinical applications and limitations of gene therapy in the management of oral cancer and precancer. We highlight the combination of gene therapy with chemotherapy (e.g., 5-Fluoracil) and immunotherapy, given the promising results obtained in the use of adenovirus to act at altered gene level (e.g., p53). Other techniques such as suicide gene therapy, use of oncolytic viruses or the use of antisense RNA have shown positive although very preliminary results. Therefore, further research into these promising gene therapy techniques is required to assess their true efficacy and safety in the management of these lesions

    Aging and passivation of magnetic properties in Co/Gd bilayers

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    Synthetic ferrimagnets based on Co and Gd bear promise for directly bridging the gap between volatile information in the photonic domain and non-volatile information in the magnetic domain, without the need for any intermediary electronic conversion. Specifically, these systems exhibit strong spin-orbit torque effects, fast domain wall motion and single-pulse all-optical switching of the magnetization. An important open challenge to bring these materials to the brink of applications is to achieve long-term stability of their magnetic properties. In this work, we address the time-evolution of the magnetic moment and compensation temperature of magnetron sputter grown Pt/Co/Gd trilayers with various capping layers. Over the course of three months, the net magnetic moment and compensation temperature change significantly, which we attribute to quenching of the Gd magnetization. We identify that intermixing of the capping layer and Gd is primarily responsible for this effect, which can be alleviated by choosing nitrides for capping as long as reduction of nitride to oxide is properly addressed. In short, this work provides an overview of the relevant aging effects that should be taken into account when designing synthetic ferrimagnets based on Co and Gd for spintronic applications.Synthetic ferrimagnets based on Co and Gd bear promise for directly bridging the gap between volatile information in the photonic domain and non-volatile information in the magnetic domain, without the need for any intermediary electronic conversion. Specifically, these systems exhibit strong spin-orbit torque effects, fast domain wall motionand single-pulse all-optical switching of the magnetization. An important open challenge to bring these materials to the brink of applications is to achieve long-term stability of their magnetic properties. In this work, we address the time-evolution of the magnetic moment and compensation temperature of magnetron sputter grown Pt/Co/Gd trilayerswith various capping layers. Over the course of three months, the net magnetic moment and compensation temperature change significantly, which we attribute to quenching of the Gd magnetization. We identify that intermixing of the capping layer and Gd is primarily responsible for this effect, which can be alleviated by choosing nitrides for cappingas long as reduction of nitride to oxide is properly addressed. In short, this work provides an overview of the relevant aging effects that should be taken into account when designing synthetic ferrimagnets based on Co and Gd for spintronic applications

    Feeding And Oviposition Preference Of Phyllophaga Cuyabana (moser) (coleoptera: Melolonthidae) On Several Crops

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    Laboratory and greenhouse experiments were carried out to study food and oviposition preference by Phyllophaga cuyabana (Moser) on different plant species as Cajanus cajan L. (pigeon pea), Crotalaria juncea L. (sun hemp), Crotalaria spectabilis Roth (showy crotalaria), Crotalaria ochroleuca G. Don (slenderleaf rattlebox), Glycine max [L.] Merrill (soybean), Gossypium hirsutum L. (cotton), Helianthus annuus L. (sunflower), Stizolobium aterrimum [Mucuna aterrima] Piper & Tracey (velvetbean) and Zea mays L. (mayze). In no-choice experiments, the number of eggs layed in sunflower, C. juncea and soybean was larger compared to cotton. Despite the fact that the adults did not discriminate among plants, in dual-choice test, the proportion of eggs layed and leaf consumption by P. cuyabana adults in soybean were significantly higher than in C. spectabilis. The larval distribution in the soil was at random in multiple-choice, withouth any trend of preference, but in dual-choice, when soybean was the control, larvae always preferred to feed on its roots. P. cuyabana adults had preference for more suitable hosts and that could stand their offspring survival. This behaviour can be usefully exploited in an integrated management program for this pest.365759764Craig, T.P., Itami, J.K., Price, P.W., A strong relationship between oviposition preference and larval performance in a shoot-galling sawfly (1989) Ecology, 70, pp. 1691-1699Diagne, A. 2004. Seasonal occurrence of Phyllophaga species and biological studies of Phyllophaga ephilida (Say) on sweet potato, Ipomoea batatas (1) Lam, in Louisiana. PhD thesis, Louisiana State University and Agricultural and Mechanical College, Baton Rouge, 101pMoron, M.A., (1986) El genero Phyllophaga en México: Morfología, distribución y sistematica supraespecifica, , México, Instituto de Ecología, 341pOliveira, L.J., B. Santos, J.R.P. Parra & C.B. Hoffmann-Campo. 2004. Coró-da-soja, p.151-176. In J.R. Salvadori, C.J. Ávila & M.T.B. da Silva (org.), Pragas de solo no Brasil. Passo Fundo, Embrapa Trigo, Embrapa Agropecuária Oeste, Fundacep, 541pOliveira, L.J., Garcia, M.A., Flight, feeding and reproductive behaviour of Phyllophaga cuyabana (Moser) (Coleoptera: Melolonthidae) adults (2003) Pesq. Agropec. Bras, 38, pp. 179-186Potter, D.A., Held, D.W., Biology and management of the Japanese beetle (2002) Annu. Rev. Entomol, 47, pp. 175-205Silva, M.T.B. da & J.R. Salvadori. 2004. Coró-das-pastagens, p.191-210. In J.R. Salvadori, C.J. Ávila & M.T.B. da Silva (org.), Pragas de solo no Brasil. Passo Fundo, Embrapa Trigo, Embrapa Agropecuária Oeste, Fundacep, 541pSilva, da, M.T.B., Tarragó, M.F.S., Link, D., Costa, E.C., Preferência de oviposição de Diloboderus abderus (Sturm) por restos de culturas em solo com plantio direto (1996) An. Soc. Entomol. Brasil, 25, pp. 83-87Rausher, M.D., Alteration of oviposition behaviour by Battus philenor butterflies in response to variation in host-plant density (1983) Ecology, 64, pp. 1028-1034Thompson, H.N., Evolutionary ecology of the relationship between oviposition preference and performance of offspring in phytophagous insects (1988) Entomol. Exp. Appl, 47, pp. 3-14Travis, B.V., Habits of the June beetle, Phyllophaga lanceolata (Say), in Iowa (1939) J. Econ. Entomol, 32, pp. 690-69

    Effects of atorvastatin treatment on sICAM-1 and plasma nitric oxide levels in hypercholesterolemic subjects.

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    This study investigated the behavior of soluble intercellular adhesion molecule-1 (sICAM-1) and serum nitric oxide (NO) products, nitrite/nitrate (NO 2-NO,-), in subjects with primary hypercholesterolemia (HCh) without other risk factors and atherosclerosis. The effect of a short-term cholesterol-lowering treatment with atorvastatin, an HMG-CoA reductase inhibitor, on the levels of sICAM-1 and NO2-/NO3 were also investigated. After 4 weeks of placebo administration, 40 HCh (15 males and 25 females) were randomized in 2 groups: 20 subjects (atorvastatin group) received 10 mg/day of atorvastatin and the remaining 20 (placebo group) continued to take placebo. At baseline and after 4 and 12 weeks of atorvastatin or placebo administration, serum sICAM-1 and NO2-/NO3-levels were evaluated. The basal levels of these parameters were compared with those of 20 healthy subjects (C), matched for sex and age. Hypercholesterolemic subjects showed sICAM-1 and NO2-/NO3-basal values that were higher (331.7 ± 60.3 ng/mL vs. 202.3 ± 32.3 ng/mL, p<0.001) and lower (10.4 ± 2.5 μmol/L vs. 20.7 ± 4.4 μmol/L, p<0.01) than controls. No correlation between sICAM-1 or NO products and plasma cholesterol values was found, whereas there was an inverse correlation between sICAM-1 and NO2-/NO3-levels. Atorvastatin administration significantly decreased sICAM-1 and increased NO2-/NO3-levels, however these changes were not correlated with the reduction of plasma cholesterol. These data support the hypothesize that patients with HCh with no signs of arterial lesions, may have latent atherosclerosis, expressed as an increase of sICAM-1 and decrease in NO product levels. An improvement in the levels of these parameters after a short-time treatment with atorvastatin was also demonstrated

    Calidad de carne de 7 razas españolas de ganado bovino vinculadas a su sistema de producción

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    En España, de modo general, el consumidor de carne de vacuno le da poca importancia a la raza en comparación con otros países Europeos, a pesar de que la misma influye en otras características que sí considera relevantes como el aspecto (color, grasa intramuscular) o la terneza. Las razas bovinas rústicas y locales españolas están ligadas a una región geográfica particular y a un sistema de erra tradicional, donde varios factores como la edad y peso al sacrificio, el sexo, el grado de engrasamiento, el manejo, la alimentación y el tratamiento post-sacrificio intervienen conjuntamente en la definición de cada producto. Estos productos suelen promocionarse a través de denominaciones de origen o marcas de calidad que, por otro lado, permiten al consumidor reducir la incertidumbre cuando compran alimentos, ya que están asociadas a ciertas características sensoriales y/o procesos productivos distintivos. Algunos autores han descrito la calidad de canal (Piedraflta et al., 2003) y las características bioquímicas (Gil et al., 2001) y sensoriales (Serra et al., 2008) de varias razas españolas vinculadas al sistema de producción, de modo que este trabajo se centra en la textura de la carne evaluada instrumentalmente y en algunas de sus características químicas. En: https://calidadcarnecita.wordpress.com/2016/02/12/calidad-de-la-carne-de-7-razas-espanolas-vinculadas-a-sus-sistema-de-produccion
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