The influence of climate on phytoplankton communities in the upper San Francisco estuary

EXTRACT (SEE PDF FOR FULL ABSTRACT): The 1977 climate shift was characterized by low chlorophyll a concentrations and a shift in phytoplankton community composition throughout the upper San Francisco Bay estuary. ... For climate to be a driving force in phytoplankton communities, it must affect mechanisms that control biomass and community composition. The influence of climate on environmental conditions and phytoplankton community composition among water-year types was examined using 19 years of physical, chemical, and phytoplankton data collected monthly at 15 stations throughout the estuary.

Investigación sobre el calamar gigante o pota en primavera 1996 en el área de Puerto Pizarro a Paita. Crucero BIC SNP-1 9609-10

Presenta los resultados de la prospección acústica pesquera, en la zona de Puerto Pizarro a Paita, hasta las 320 millas náuticas de distancia a la costa, del 25 de setiembre al 20 de Octubre 1996. El recurso se encontró muy disperso en casi toda el área prospectada, asociado a temperaturas superficiales y salinidades.

Propuesta metodológica para la evaluación del aprender haciendo en la escuela agrícola panamericana. Honduras, CA.

Elaborar una metodología de evaluación que permita el seguimiento de la experiencia concreta de la Escuela Agrícola Panamericana (EAP). Recopilar información que permita visualizar el proceso del Aprender Haciendo. El objeto de estudio es la evaluación y su aplicación en la formación de profesionales agrícolas o agrónomos. Para el diagnóstico de necesidades se parte de las valoraciones sobre las distintas asignaturas del Programa de Agrónomo de un grupo de alumnos. Dicho grupo está integrado por 31 de primero, 112 de segundo y 40 de tercero de los 3 años respectivos del Programa. El trabajo se divide en dos partes. En la primera se analiza desde un marco teórico la evaluación: su finalidad, su objeto, los recursos metodológicos que se precisan para ponerla en práctica, los diferentes modelos objetivistas y subjetivistas. Se establecen también los diseños de investigación educativa que pueden utilizarse así como las indicaciones generales para la construcción de instrumentos de recogida de información. En la segunda parte se desarrolla la propuesta de evaluación del sistema de aprendizaje diseñado para el Aprender Haciendo. Se lleva a cabo una amplia revisión bibliográfica sobre el tema tratado y se parte de los datos de una encuesta para observar la importancia y la calidad de cada asignatura en el plan de estudios. El enfoque es preferentemente descriptivo, realizándose una valoración cualitativa y selectiva de la información. De los datos cuantitativos obtenidos se contemplan las medias. Se trata de constatar si el sistema de aprendizaje que se diseñó es el que verdaderamente se ejecuta en el campo. Para obtener un panorama del diseño de cada uno de los 47 módulos de campo que componen el Aprender Haciendo se procede a extraer información a través de las guías modulares. En ellas se registra el nombre de la práctica, la meta instruccional, los objetivos propuestos, la descripción de la misma y la forma de evaluación. Los alumnos contarán además con un instrumento de evaluación que será el resultado de una combinación de una lista de control, de una escala estimativa de valoración y de un diario del alumno. Se observa que si se quiere seguir avanzando en la línea de la propuesta para obtener una evaluación más completa será preciso: 1. Involucrar a los instructores de módulo en el proceso de planificación de la evaluación de los resultados. 2. Nombrar una comisión para que coordine y brinde apoyo logístico a los instructores, particularmente a los de estadística. 3. Utilizar el diseño cuasiexperimental, denominado diseño de comparación estática con prestest que permite cuatro tipos de comparaciones, con la finalidad de no interferir con la programación en el desarrollo normal de los módulos.

Caminos rurales de la comarca de las Villuercas : ca??adas ganaderas y v??as de ferrocarril abandonadas

Proyecto de recuperaci??n de caminos rurales existentes en la comarca de las Villuercas (C??ceres) como una forma de acercamiento del medio a los alumnos. Los objetivos del trabajo son: conocer las principales v??as pecuarias de la comarca, analizar la incidencia de la trashumancia en la zona desde la Edad Media a la actualidad, describir el trazado del ferrocarril de las Villuercas, elaborar un inventario de caminos rurales de la comarca, descubrir y aumentar en los alumnos el inter??s por la naturaleza y la conservaci??n del medio, analizar de forma cr??tica las p??rdidas econ??micas y consecuencias sociales derivadas de la falta de planificaci??n y uso inadecuado de los recursos, familiarizarse con la b??squeda de informaci??n en documentos hist??ricos, mapas, planos, etc., aprender a elaborar informes y trabajos monogr??ficos acerca de temas importantes del entorno y obtener informaci??n inmediata sobre hechos y acontecimientos del entorno utilizando la historia oral.

La Ca??ada Leonesa

Gu??a que pretende animar al conocimiento de las ca??adas. Propone un itinerario que parte de la Sierra de Guadarrama y llega hasta Talavera de la Reina. Hace una introducci??n hist??rica y describe brevemente el medio natural..

Producció artística i consum domèstic: el mobiliari i l’abillament de la casa de Miquel Mai (c.1475-1546)

Investigació històrica sobre l’ambientació d’una casa senyorial, ubicada a la Plaça de la Cucurulla, a la Barcelona de la primera meitat del segle XVI així com dels avatars del personatge principal que va habitar la dita casa, en Miquel Mai

Electronic and optical properties of grossular garnet (Ca(3)Al(2)Si(3)O(12)): An ab initio study

The electronic and optical properties of grossular garnet are investigated using density functional theory (DFT) within generalized gradient approximation (GGA). The calculated lattice parameters are in good agreement with the experiment data. The electronic structure shows that grossular has a direct band gap of 5.22 eV. The dielectric functions, reflective index, extinction coefficient, reflectivity and energy-loss spectrum are calculated. The optical properties of grossular are discussed based on the band structure calculations. The O 2p states and Si 3s play a major role in these optical transitions as initial and final states, respectively. The absorption spectrum is localized in the ultraviolet range between 30 and 250 nm. Finally, we concluded that pure grossular crystal does not absorb radiation in the visible range. (c) 2009 Elsevier B.V. All rights reserved.

Rhyacian (2.23-2.20 Ga) juvenile accretion in the southern Sao Francisco craton, Brazil: Geochemical and isotopic evidence from the Serrinha magmatic suite, Mineiro belt

The Serrinha magmatic suite (Mineiro belt) crops out in the southern edge of the Sao Francisco craton, comprising the Brito quartz-diorite, Brumado de Cima and Brumado de Baixo granodiorites, granophyres and felsic sub-volcanic and volcanic rocks, part of which intruded into the Nazareno greenstone belt. The suite rocks have petrographic features that are consistent with magma supercooling due to the low water content combined with volatile loss, leading to crystallization of quartz and alkaline feldspar at the rims of plagioclase phenocrysts (granophyric intergrowth). The investigated rocks are sub-alkaline, calc-alkaline and show low content in rare earth elements. The U-Pb zircon crystallization ages for the Brumado de Cima granodiorite [2227 +/- 22 (23) Ma] and a coeval granophyre [2211 +/- 22 (23) Ma], coupled with available single-zircon Pb evaporation ages for the Brito and Brumado de Baixo plutons, are significantly older than the ""Minas orogeny"" (ca. 2100-2050 Ga) of Quadrilatero Ferrifero area, eastward from the Serrinha suite. Our data establish an early Rhyacian event tectonically linked with the evolution of the Mineiro belt. The bulk Nd isotopic signature [low negative to positive epsilon(Nd(t)) values] of the Serrinha samples are consistent with the important role of Paleoproterozoic mantle components in the magma genesis. The integrated geologic, geochemical and isotopic information suggests that Paleoproterozoic evolution of the Mineiro belt initiated in a passive continental margin basin with deposition of the Minas Supergroup at ca. 2500 Ma. This stage was succeeded by outboard rupture of the oceanic lithosphere with development and coalescence of progressively younger magmatic arcs during Rhyacian time. One of the earliest arcs formed the Serrinha suite. The tectonic collage of the Serrinha and Ritapolis (2190-2120 Ma) arcs produced the NE-SW Lenheiro shear zone, resulting in mylonitization and recrystallization of both the granitoid intrusions and host rocks. As a matter of fact juxtaposition of distinct magmatic units in age and origin took place along the Lenheiros structure in this sector of the Mineiro belt. (C) 2009 Elsevier Ltd. All rights reserved.

Conversor CC/CA de alta freqüência baseado em inversores ressonantes com comutação seqüencial para excitação de uma tocha indutiva a plasma térmico

This work describes the study, the analysis, the project methodology and the constructive details of a high frequency DC/AC resonant series converter using sequential commutation techniques for the excitation of an inductive coupled thermal plasma torch. The aim of this thesis is to show the new modulation technique potentialities and to present a technological option for the high-frequency electronic power converters development. The resonant converter operates at 50 kW output power under a 400 kHz frequency and it is constituted by inverter cells using ultra-fast IGBT devices. In order to minimize the turn-off losses, the inverter cells operates in a ZVS mode referred by a modified PLL loop that maintains this condition stable, despite the load variations. The sequential pulse gating command strategy used it allows to operate the IGBT devices on its maximum power limits using the derating and destressing current scheme, as well as it propitiates a frequency multiplication of the inverters set. The output converter is connected to a series resonant circuit constituted by the applicator ICTP torch, a compensation capacitor and an impedance matching RF transformer. At the final, are presented the experimental results and the many tests achieved in laboratory as form to validate the proposed new technique

Magmatismo há ca. 660 - 640 Ma no Domínio Socorro: Registros de convergência-colisional na Aglutinação do Gondwana Ocidental

Uranium-lead zircon ages between 660 and 640 Ma, obtained from a series of calc-alkaline orthogneisses and plutons in southeast Brazil's Central Mantiqueira Province, suggest that a significant period of magmatism occurred in this region prior to the collisional assembly of West Gondwana (presently constrained in the region between ca. 625 and 580 Ma). While the nature of this earlier magmatism is presently unclear, some preliminary Sm-Nd data suggest that these magmas were not solely derived from the Paleoproterozoic lithosphere, but appear to represent hybrid products of Paleoproterozoic and Neoproterozoic sources. As such hybrid mixtures have been most commonly observed in continental are settings, it is possible that the 660 to 640 Ma magmatism represents are magmatism that resulted from subduction of Neoproterozoic oceanic crust during early precollisional convergence and closure of a branch of either the Adamastor or Goianides oceans.

Compartimentos de K, Ca e Mg em solos e sua relação com o crescimento inicial, fisiologia e produtividade do eucalipto

Forestry has grown in a continuous and accelerated manner in Brazil, constituting a strategic activity for the generation of employment, income and tributes, favoring social and economic development of Brazilian agribusiness. The objectives of this study were: (1) evaluate the contents of K, Ca and Mg in the reserve compartments, non-interchangeable, interchangeable, available and the speed of its release, its correlations and its effects over productivity (annual average increment – AAI) of eucalyptus plantations, in forest sites cultivated in soils of the state of Rio Grande do Sul; (2) evaluate the initial growth, nutrition and physiological aspects of eucalyptus plants, cultivated with and without the addition of mineral sources of potassium (K), calcium (Ca) and magnesium (MG), in soils obtained from forest sites in the state of Rio Grande do Sul. In the first study, contents of K, Ca and Mg were evaluated in sulfuric digestion extract, boiling nitric acid, ammonium chloride, Mehlich-1 (only K), potassium chloride (Ca and Mg), as well as the release speed of these nutrients in the soil. In the second study, growth variables, nutritional aspects, photosynthetic rate (A) and transpiration rate of the plants (E) grown in distinct soils were evaluated under controlled conditions. The contents of K, Ca and Mg varied between compartments and depths in the studied soil classes, with the highest proportions found in the reserve compartment, indicating the importance of this compartment for the supplement of these nutrients at average and long terms. The great majority of K, Ca and Mg compartments presented significant correlations between each other, showing the dependence between them and the importance of evaluating the contents of these nutrients in the different compartments to adapt the nutritional management of the plants to each soil class, and to obtain continuous productions, minimizing the negative effects to the environment. Plants cultivated in soils that present larger reserves, availability and K, Ca and Mg release kinetics, presented similar height (H), stem diameter (SD) and shoot dry mass (SDM), with or without fertilization with K, Ca and Mg. The plants presented higher leaf content and accumulation of K in all soils fertilized with K, Ca and Mg.

Reguladores vegetais na brotação, características dos cachos e produtividade da videira cv. Itália no Vale do São Francisco, BA

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Detrital Zircon Evidence for Non-Laurentian Provenance, Mesoproterozoic (ca. 1490-1450 Ma) Deposition and Orogenesis in a Reconstructed Orogenic Belt, Northern New Mexico, USA: Defining the Picuris Orogeny

Detrital zircon and igneous zircon U-Pb ages are reported from Proterozoic metamorphic rocks in northern New Mexico. These data give new insight into the provenance and depositional age of a >3-km-thick metasedimentary succession and help resolve the timing of orogenesis within an area of overlapping accretionary orogens and thermal events related to the Proterozoic tectonic evolution of southwest Laurentia. Three samples from the Paleoproterozoic Vadito Group yield narrow, unimodal detrital zircon age spectra with peak ages near 1710 Ma. Igneous rocks that intrude the Vadito Group include the Cerro Alto metadacite, the Picuris Pueblo granite, and the Penasco quartz monzonite and yield crystallization ages of 1710 +/- 10 Ma, 1699 +/- 3 Ma, and 1450 +/- 10 Ma, respectively. Within the overlying Hondo Group, a metamorphosed tuff layer from the Pilar Formation yields an age of 1488 +/- 6 Ma and represents the first direct depositional age constraint on any part of the Proterozoic metasedimentary succession in northern New Mexico. Detrital zircon from the overlying Piedra Lumbre Formation yield a minimum age peak of 1475 Ma, and similar to 60 grains (similar to 25%) yield ages between 1500 Ma and 1600 Ma, possibly representing non-Laurentian detritus originating from Australia and/or Antarctica. Detrital zircons from the basal metaconglomerate and the middle quartzite member of the Marquenas Formation yield minimum age peaks of 1472 Ma and 1471 Ma, consistent with earlier results. We interpret the onset of ca. 1490-1450 Ma deposition followed by tectonic burial, regional Al2SiO5 triple-point metamorphism, and ductile deformation at depths of 12-18 km to reflect a Mesoproterozoic contractional orogenic event, possibly related to the final suturing of the Mazatzal crustal province to the southern margin of Laurentia. We propose to call this event the Picuris orogeny.

La glosa de 1541 a los refranes que dizen las viejas tras el fuego

Los Refranes que dizen las viejas tras el fuego del Marqués de Santillana tuvieron una extendida difusión en el siglo XVI. La impresión que de ellos hizo Francisco Fernández de Córdoba en 1541 no sólo marca una particular forma de recepción, la de la colección ilustrada con breves glosas morales, sino que, además, fue una de las fuentes fundamentales de Juan de Mal Lara al componer su Philosophia vulgar (Sevilla, 1568). Se realiza aquí una transcripción de esta impresión de 1541 a partir del único impreso que la conserva, mejorando la edición que realizó Sbarbi (1874). Con esto se pretende acercar materiales para el estudio de la primitiva etapa impresa del Refranero hispánico.

La glosa de 1541 a los refranes que dizen las viejas tras el fuego

Los Refranes que dizen las viejas tras el fuego del Marqués de Santillana tuvieron una extendida difusión en el siglo XVI. La impresión que de ellos hizo Francisco Fernández de Córdoba en 1541 no sólo marca una particular forma de recepción, la de la colección ilustrada con breves glosas morales, sino que, además, fue una de las fuentes fundamentales de Juan de Mal Lara al componer su Philosophia vulgar (Sevilla, 1568). Se realiza aquí una transcripción de esta impresión de 1541 a partir del único impreso que la conserva, mejorando la edición que realizó Sbarbi (1874). Con esto se pretende acercar materiales para el estudio de la primitiva etapa impresa del Refranero hispánico.