Sustainable management in pecan cultivation in Argentina

243-248Pecan nut "Carya illinoinensis" is native from central and western U.S.A. and arrived in Argentina in the nineteenth century. The difference with other nuts is that it presents an 80 percent oil composition, with polyunsaturated fatty acids omega 3 and 6 that help to reduce cholesterol and also prevent the risk of cardiovascular disease. It contains an antioxidant: vitamin E, and has a high content of fibre that helps to prevent colon cancer. Reduces bad cholesterol, helps keep blood pressure low and is recommended especially for patients with cancer and cardiac problems. A pecan sustainable farming system intends to be productive but at the same time, to preserve enviromental quality, favouring the use of biological practices over chemical inputs. Surface application of compost to pecan trees, is a common practice in organic orcharding. The objectives of the work were to compare compost and vermicompost with liquid fertilizer and a control without fertilization in a completely random block design with four replications, in a one-year crop with a planting frame of 8m x 8m. The application of organic amendments produced statistically significant changes in soil properties with reference to inorganic fertilizer, especially in the total carbon, microbial biomass carbon and phosphorus. Compost and vermicompost treatments produced statistically significant increases in factors related to production as tree height and diameter

Fertilización de base en un cultivo inicial de pecan con dos marcos de plantación de alta densidad

91-97The fruit of the pecan tree, Carya illinoensis Koch, is considered a very healthy food. In Argentina, pecan cultivation has been expanding rapidly but very little research has been conducted on pecan fertilization and planting systems. The objectives of this study were to characterize some physical-chemical and chemical properties in a pecan crop, and compare different basal fertilization (FB) treatments under two high density plantation frames (MP). Plantation was conducted in Villanueva (Buenos Aires province), on a Tapthoargic Hapludoll, with 10 x 10 m frames (real part: MR) and 8 x 8 m frames (staggered: TR). The experimental design was a split plot with four replications. The main plots were the two frames and the subplots were the different fertilization treatments: Compost (C), Phosphorus (P), slow release Nitrogen (N), and an unfertilized control (T). The determinations to assess the growth of pecan plants were: plant height and stem diameter. With regard to soil fertility, phosphorus fertilization and the addition of compost significatively increased the levels of Bray-P. The organic fertilizer treatment (compost) showed a significant increase in the height of the pecan plantation under the 8 x 8 m frame, which was not apparent in any case for the stem diameter, with a MP x FB significant interaction (P = 0.01) for height variation in the first year. The plantation frame with or without basal fertilization had no effect on pecan volume during the study period

Bioensayos de toxicidad aguda con Lactuca sativa en sedimentos contaminados del Río Reconquista en disposición final

p.179-185Se realizaron dos ensayos de toxicidad aguda con semillas de Lactuca sativa para evaluar la biotoxicidad en sedimentos contaminados y dispuestos del río Reconquista. Se aplicaron tres tratamientos: testigo arena (A); sustrato compuesto por arena-sedimento al 50 por ciento (AS) y sustrato 100 por ciento sedimento (S). Se midió número de plántulas, longitud radical y se observaron indicadores de fitotoxicidad. Hubo diferencia entre tratamientos en el número de plantas que emergieron (P menor que 0,02). Se observó necrosis en los cotiledones en AS y S. En el segundo bioensayos, a partir del extracto sedimento:agua 1:2,5 se trabajó con cuatro diluciones (1:1, 1:5, 1:10 y 1:25) y testigo de agua destilada. La longitud radical entre los tratamientos y el testigo fue significativa (P menor que 0,05) : X 7,24 mm para el extracto más concentrado, 11,91 mm para el más diluido y 13,79 mm para el control. Se estimó CE20 para una dilución de 1:13. La solución más concentrada se aproxima a la CE50, con crecimiento anormal de pelos radicales y radículas delgadas. Los efectos de fitotoxicidad identificados pueden ser atribuibles a la gran acidez del sedimento, alto contenido de aluminio, presencia de metales pesados y de hidrocarburos. Se vincula la necrosis observada en ambos bioensayos con un estrés oxidativo inducido por la deficiencia de calcio y el exceso de cadmio

Fósforo extractable y fósforo orgánico lábil como indicadores de calidad de suelos de Entre Ríos

p.41-46En un Argiudol vértico de la provincia de Entre Ríos, se estudió la variación de los niveles de P extractable según los métodos de Bray y Olsen , y el P orgánico lábil. El fósforo orgánico lábil encontró su máximo en la situación prístina del monte y fue disminuyendo con la degradación. El coeficiente de correlación entre P orgánico lábil y C oxidable fue r igual a 0,95 (p menor a 0,05) y con C liviano fue rigual a 0,96 (p menor a 0,05). En cuanto a los niveles de P extractable por Bray y Olsen , sus tendencias pueden estar influidas por la fertilización fosfatada, aporte necesario en este tipo de suelos para un normal desarrollo de los cultivos, por lo que no podrían tomarse como indicadores válidos. El P orgánico lábil se comportó como un indicador sensible a la degradación o disminución de calidad del suelo , y su variación estuvo correlacionada con la declinación de los contenidos de carbono

The Elusive Third Subunit IIa of the Bacterial B-Type Oxidases: The Enzyme from the Hyperthermophile Aquifex aeolicus

The reduction of molecular oxygen to water is catalyzed by complicated membrane-bound metallo-enzymes containing variable numbers of subunits, called cytochrome c oxidases or quinol oxidases. We previously described the cytochrome c oxidase II from the hyperthermophilic bacterium Aquifex aeolicus as a ba3-type two-subunit (subunits I and II) enzyme and showed that it is included in a supercomplex involved in the sulfide-oxygen respiration pathway. It belongs to the B-family of the heme-copper oxidases, enzymes that are far less studied than the ones from family A. Here, we describe the presence in this enzyme of an additional transmembrane helix “subunit IIa”, which is composed of 41 amino acid residues with a measured molecular mass of 5105 Da. Moreover, we show that subunit II, as expected, is in fact longer than the originally annotated protein (from the genome) and contains a transmembrane domain. Using Aquifex aeolicus genomic sequence analyses, N-terminal sequencing, peptide mass fingerprinting and mass spectrometry analysis on entire subunits, we conclude that the B-type enzyme from this bacterium is a three-subunit complex. It is composed of subunit I (encoded by coxA2) of 59000 Da, subunit II (encoded by coxB2) of 16700 Da and subunit IIa which contain 12, 1 and 1 transmembrane helices respectively. A structural model indicates that the structural organization of the complex strongly resembles that of the ba3 cytochrome c oxidase from the bacterium Thermus thermophilus, the IIa helical subunit being structurally the lacking N-terminal transmembrane helix of subunit II present in the A-type oxidases. Analysis of the genomic context of genes encoding oxidases indicates that this third subunit is present in many of the bacterial oxidases from B-family, enzymes that have been described as two-subunit complexes

290 surgical procedures for ulnar nerve entrapment at elbow: physiopathology, clinical experience and results.

Ulnar nerve entrapment at the elbow is an important and relatively frequent pathological condition that may be related to different causes depending on individual or external factors. The cause of the nerve lesion is also idiopathic in about one-quarter to one-third of cases. This variable aetiopathogenetic presentation has often suggested different diagnostic and clinical approaches and, moreover, various surgical procedures. We present our 8-years surgical experience with 290 cases of ulnar nerve entrapment at the elbow analysing the salient clinical features and the results of the surgical treatment in the light of the relevant literature available on this topic

Design guidelines for axial turbines operating with non-ideal compressible flows

The impact of non-ideal compressible flows on the fluid-dynamic design of axial turbine stages is examined. First, the classical similarity equation (CSE) is revised and extended to account for the effect of flow non-ideality. Then, the influence of the most relevant design parameters is investigated through the application of a dimensionless turbine stage model embedding a first-principles loss model. The results show that compressibility effects induced by the fluid molecular complexity and the stage volumetric flow ratio produce an offset in the efficiency trends and in the optimal stage layout. Furthermore, flow non-ideality can lead to either an increase or a decrease of stage efficiency up to 3-4% relative to turbines designed to operate in dilute gas state. This effect can be predicted at preliminary design phase through the evaluation of the isentropic pressure-volume exponent. Three-dimensional (3D) RANS simulations of selected test cases corroborate the trends predicted with the reduced-order turbine stage model. URANS computations provide equivalent trends, except for case study niMM1, featuring a non-monotonic variation of the generalized isentropic exponent. For such turbine stage, the efficiency is predicted to be higher than the one computed with any steady-state model based on the control volume approach. Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Flight Performance and Propulsio

NiceProp: An interactive Python-based educational tool for non-ideal compressible fluid dynamics

Non-ideal compressible flows exhibit physical behaviors that are quantitatively and qualitatively different than those of a perfect or ideal gas. As such, the classical gas dynamic relationships that can be found on fluid-mechanics textbooks cannot be directly applied to characterize this type of flows. NiceProp is a tool for interactively learning the fundamentals of non-ideal compressible fluid dynamics and the design implications for fluid machinery components. The software is written in Python and features a highly modular structure to ease code readability and to facilitate its further development. The target audience of the software is represented by students, researchers and industry professionals interested to get started or deepen the comprehension of non-ideal compressible flow phenomena.Flight Performance and Propulsio