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Digital.CSIC (67,728 recursos)
Repositorio institucional del Consejo Superior de Investigaciones Científicas. Digital.CSIC es un depósito de documentos digitales, cuyo objetivo es organizar, archivar, preservar y difundir en modo de acceso abierto la producción intelectual resultante de la actividad investigadora del CSIC.

(IRN) Artículos post-print

Mostrando recursos 1 - 20 de 111

1. Searching for Guidelines for "Ecological Thought" Development - Hernández, A. J.; Pastor PIñeiro, Jesús
The present work is concerned with eliciting objectives for a project aimed at the development of "ecological thought". For our purposes, we start from interactions among ecological studies teaching what we have called "ecological thought" and initiation procedures for ecological method learning and understanding, so as to infer positive population behaviour patterns, the interacting system being a university student population and the environment. In order to define the main elements within the system, we have studied 33 variables belonging to social, cultural, psychological and scientific components. The employed methodology combines the scientific method—which is used in the investigation of a particular ecological problem—and the ecological method, which we apply to educational dynamics...

2. Phytoremediation studies of Zn polluted soils using - Pastor Piñeiro, Jesús; Hernández, A. J.; Prieto, Nuria
In the South of Madrid, áreas occupied by abandoned urban and industrial waste landfills, are the most polluted soils (CAM, 1998). In these zones, physical degradation, salinisation (Pastor et al. 1993a; Hernández et al. 1998) and heavy metal pollution are the most significant. Among the heavy metáis present, Zn is particularly problematic. The Zn levéis of the cover soils of these landfills are 600 ppm, but they do approach valúes for which remediation measures are recommended, and even surpass these in áreas prone to leaching (Hernández et a/., 1998). One such measure is the use of native plants that are capable of growth in polluted soil. This...

3. Ecological engineering in the management of an olive orchard on degraded soil - Pastor Piñeiro, Jesús; Hernández, A. J.
THIS report describes the results obtained ¡n a field experiment performed on an olive orchard, in which the soil is sandy and impoverished. Our study forms part of a project whose main aim is to evalúate ecological management systems directed towards the conservation of soil in semiarid áreas. At the start of our analysis, we noted two critical points: soil erosión and a degraded soil with extremely low levéis of organic matter, N and other nutrients. To resolve these problems from a perspective of sustainable agricultura, it was decided to implant or to propitiate the growth of plant covers between rows of trees that would be...

4. Effect of Heavy Metals from Mine Soils on Avena Sativa L.and Education Strategies - Gutiérrez Ginés, Mª Jesús; Pastor Piñeiro, Jesús; Hernández, A. J.
Heavy metals in the soils of old mining areas, besides affecting the productivity of their ecosystems, could also affect animal and human health. To test this hypothesis, we assessed the bioavailability of heavy metals to forage crops used as human food sources or components of fodder. The sites examined were the surrounding soils of two abandoned mines in Central Spain polluted with Al, Fe, Mn, and more than one of the heavy metals Zn, Pb, Cd, Cu, Cr or Ni, and As. All elements were determined by plasma emission spectroscopy with the exception of As, which was quantified by XRF. Levels of Zn, Pb, Cd, Cu and Fe were high in...

5. Oxidation-reduction potentials of feredoxin-NADP+ reductase and flavodoxin from Anabaena PCC 7119 and their electrostatic and covalent complexes - Pueyo, José J.; Gómez-Moreno, Carlos; Mayhew, Stephen G.
The oxidation-reduction potentials of ferredoxin-NADP' reductase and flavodoxin from the cyanobacterium Anuhaena PCC 7119 were determined by potentiometry. The potentials at pH 7 for the oxidized flavodoxin/ flavodoxin semiquinone couple (E2) and the flavodoxin seniiquinone/hydroquinone couple (El) were - 21 2 mV and -436 mV, respectively. El was independent of pH above about pH 7, but changed by approximately -60 mV/pH below about pH 6, suggesting that the fully reduced protein has a redox-linked pK, at about 6.1, similar to those of certain other flavodoxins. E2 varied by - 50 mV/pH in the range pH 5 - 8. The redox potential for the two-electron reduction of...

6. Preparados para sobrevivir (Ciencia y desarrollo ecología y desarrollo) - Pastor Piñeiro, Jesús
El desarrollo de la ciencia y de la técnica de una sociedad es parte de su avance cultural, y en una sociedad moderna es parte central de dicho desarrollo. Por tanto, el progreso científico y técnico no puede darse con independencia del desarrollo cultural, lo que a su vez no puede producirse sin un desarrollo económico y político paralelo. Es un hecho que, aunque puede haber investigaciones originales y valiosas en condiciones políticas y económicas duras, no puede existir un desarrollo científico y técnico integral y sostenido, a menos que exista libertad política, tolerancia intelectual y cierta holgura económica. En suma, el desarrollo científico-técnico y económico requiere el avance de la sociedad en todos sus aspectos.

7. Molecular and functional analysis of α-amylase inhibitor genes and proteins in the common bean Phaseolus vulgaris - Mirkov, T. E.; Pueyo, José J.; Mayer, J. E.; Kjemtrup, S.; Cardona, C.; Chrispeels, Maarten J.
Bean (Phaseolus vulgaris) seeds accumulate three evolutionarily related plant defense proteins: phytohemaglutinin (PHA), arcelin (Arc) and α-amylase inhibitor (αAI). we identified the gene that encodes snap bean(cv. Greensleeves) αAI on the basis of a partial amino acid sequence of purified αAI supplied by John Whitaker (UC Davis), and the expression of the gene in tobacco seeds.

8. Independent induction of two blue light-dependent monovalent anion transport systems in the plasma membrane of Monoraphidium braunii - Mora, Cristina; Witt, Federico G.; Aparicio, Pedro J.; Quiñones, Miguel Angel
In the plasma membrane of the green alga Monoraphidium braunii there are at least two monovalent anion transport systems. One of them is specific for bicarbonate. This transport system is activated by blue light and its induction is triggered by a decrease in the external CO2 concentration. The second transport system is responsible for nitrate uptake at least. This transport system is also activated by blue light and its induction occurs when there is no ammonium in the external medium. Both transport systems are synthesized independently. Hence, when M. braunii cells grow with nitrate as the only nitrogen source under...

9. La revegetación de vertederos de residuos urbanos basada en principios ecológicos - Hernández, A. J.; Pastor Piñeiro, Jesús
El mayor nivel de degradación de ecosistemas terrestres se da en aquellos casos en los que la misma es debida a la interacción erosión-contaminación. En la situación actual, los vertederos de residuos sólidos urbanos (VRSU) que son clausurados nos permiten tener una visión adecuada para la investigación acerca de la rehabilitación de dichos ecosistemas. Sin duda, el proceso de la revegetación ha sido considerado como primario a fin de conseguir nuestros objetivos. La metodología ha consistido en estudiar comparativamente (91 estaciones de muestreo) tres vertederos con presencia de erosión-contaminación y los ecosistemas del entorno que tuvieron abundancia en especies herbáceas, ya que las primeras etapas de la...

10. Nutrient recycling as an ecological basis for the technologies involved in a sustainable development in semiarid mediterranean rangelands - Pastor Piñeiro, Jesús; Hernández, A. J.; Bello, A.
Recycling is the central axis for the conservaron of ecosystems ¡n the scenario of sustainable development. This subject implies the study of an important frame of interactions. Nevertheless, the complex study of nutrient recycling in agroecosystems would be reduced on the basis of the actual knowledge of the soil biocenoses, mainly represented by soil nematodes. Nematodes are indicator organisms of several processes related with the trophic structure of soil systems. This question, combined with the study of nematode interactions with the herbaceous communities growing over these soils, can provide guidelines for a more rational planning of pasture management. The results of our work show that nematode density is posrtively...

11. In situ microscopical diagnosis of biodeterioration processes at the convent of Santa Cruz la Real, Segovia, Spain - Ríos, Asunción de los; Galván, Virginia; Ascaso, Carmen
This report describes the in situ evaluation of biodeterioration processes occurring in the stone (granodiorite and carbonate) of the Convento de Santa Cruz la Real, Segovia, Spain. Scanning electron microscopy with back-scattered electron imaging (SEM–BSE) and 11 X-ray microanalysis were used to examine stone samples from the convent. Free-living algae and fungi, lichen thalli, mosses, cyanobacteria and bacterial colonies were observed. Some of these organisms were located epilithically, while others were found to inhabit ssures 13 or cavities inside the lithic substrate, a few of which showed an euendolithic ecological niche. Biogeomechanical and biogeochemical processes associated with the presence and action of lithobiontic microorganisms were...

12. The effect of desiccation on cell shape in the lichen Parmelia Sulcata taylor - Brown, D. H.; Rapsch, S.; Beckett, A.; Ascaso, Carmen
Comparisons have been made of the shape of algal cells in the lichen Parmelia sulcata which was subjected to controlled desiccation regimes inducing substantial water loss. The spherical appearance of algal cells obtaiiíed by conventional techniques for transmission electrón microscopy (TEM) was shown by low temperature scanning electrón microscopy (LTSEM) to be the consequence of rapid rehydration during fixation. Collapse of the walls of algal cells and fungal hyphae in the medulla and algal layer when desiccated were observed with LTSEM and shown to be reversible on rehydration. Desiccation-induced contraction of cortical fungal protoplasts was detected with LTSEM. Fixation with osmium vapour only before TEM demonstrated a similar...

13. Temporal variations in the carbon budget of forest ecosystems in Spain - Rodríguez Murillo, Juan Carlos
Temperate and boreal forests of the Northern Hemisphere have recently been identified as important carbon sinks. Accurate calculation of forest carbon budget and appraisal of the temporal variations of forest net carbon fluxes are important topics to elucidate the ‘‘missing sink’’ question and to follow up the changing carbon dynamics in forests. In this article, recent carbon budgets of the forests of a region in northern Spain have been calculated using data from forest inventories and a carbon cycle model for the human perturbations to the forests. Two methods are used, one that requires data from two forest inventories (growing stocks), and another that uses data from only...

14. Sedimentation in the semi-arid freshwater wetland Las Tablas de Daimiel (Spain) - Sánchez Carrillo, Salvador; Álvarez Cobelas, Miguel; Angeler, D. G.
Despite sedimentation being recognized as a very important process in wetlands, very little is known about its dynamics. This study analyzed sedimentation on a short-term scale in the semiarid floodplain wetland Las Tablas de Daimiel National Park (central Spain). In monthly sampling intervals during 1997 and 1998, we measured seasonal and spatial sedimentation patterns of total solids, organic and mineral matter, nitrogen, and phosphorus using sediment traps. The highest mean mass accumulation rates were obtained at the wetland-input site (135 ± 57 g m−2 d−1), but a decrease in sedimentation rates was noted with increasing distance from the inflow (49...

15. Cultivation-Induced Effects on the Organic Matter in Degraded Southern African Soils - Pardo, Mª Teresa; Almendros, G.; Zancada, M. C.; López-Fando, Cristina; González-Vila, F.J.
We studied quantitative and qualitative changes in soil organic matter (SOM) due to different land uses (reference woodland versus cultivated) on six soils from Tanzania (Mkindo and Mafiga), Zimbabwe (Domboshawa and Chickwaka), and South Africa (Hertzog and Guquka). Structural characteristics of the humic acids (HAs) were measured by Curie-point pyrolysis–gas chromatography/mass spectrometry (Py–GC/MS) and solid-state 13C nuclear magnetic resonance (CPMAS 13C NMR) spectroscopy. Significant changes in concentration and composition of SOM were observed between land uses. Losses of organic carbon after cultivation ranged from 35% to 50%. Virgin soils showed large proportions of colloidal humus fractions: humic acids (HAs) and fulvic acids (FAs) but negligible amounts of not-yet decomposed...

16. Mutants of coliphage BF23 able to propagate on smooth strains of Salmonella Typhimurium - Mojica-A, T.; García, E.; Ascaso, Carmen
Mutants of coliphage BF23 able to propágate on smooth strains of Salmonella typhimuríum. The host range of a bacteriophage can be modified by mutation (and/or recombination) either of the host and/or of the bacteriophage. We have previously reported (MOJICA-A & CHARLES, 1975) that coliphage BF23 was able to propágate on rough strains (mutation of the host) of Salmonella typhimurium (strains with incomplete lipopolysaccharide of the cell wall), and that the sensitivity of rough strains was dependent on the presence of an intact bfe+ gene. Moreover the inability of the phage to propágate on smooth strains was due to failure of the phage to absorb to the bacterial cells. Unmutagenized stocks of phage...

17. Leguminosas y gramineas como base para la tipificación de pastos. II comunidades de caracter subhúmedo y xerofítico - Pastor Piñeiro, Jesús; Oliver, Salvador; Gómez Sal, A.
Using only legume and grass species, we pretend to characterize a group of pastures, subhumid and xerophytic by means of an ordination analysis. This analysis differentiates clearly the communities with mesomediterranean bioclimatic characteristics from those with supramediterranean ones. The transition between both bioclimatic environments is defined by the "tomillar- pasto" (al. Brachypodion phoenicoidé) and 'lastonares" (al. Festuco-Poion ligulatae) according to topographic and soil characteristics. Given the complex character of these subhumid pastures, in the southem limit of their distribution área, the use of only these species belonging to the above mentioned families, is not sufficient to differentiate the main types of communities described for the studied área, although it does...

18. Boron, Zinc, Iron, and Manganese Content in Four Grassland Species - Adarve, M. J.; Hernández, A. J.; Gil, A.; Pastor Piñeiro, Jesús
A pot experiment was carríed oul to test the response of the B, Zn, Fe, and Mn concentraron in four wild herbaceous specics exposcd to three landñll leachate treatments of increasing concentration of contaminants. The species tested «ere clustered clover (Trifolium (¡lomera tum L.), col ton clover (T. tomentosum L.), wall barley (Hordeum murinum L.), and soft brome (Bromus hordaceus L.). The legume specics accumulated more Fe and B than the grasses. The least contaminated leachate (leachate A) significantly increased the Fe and Mn content in T. glomeratum. Leachate B significantly increased the Zn content in both clover species and Fe content in T. glomeratum and H. murinum, while it...

19. Efecto de diferentes tipos de uso sobre los componentes edáfico y biótico de agroecosistemas de secano - Hernández, A. J.; Pastor Piñeiro, Jesús; Estalrich, E.; Urcelay, A.; Lacasta Dutoit, Carlos
Los principales problemas ambientales asociados con las prácticas cerealistas en la submeseta sur son la evolución negativa de las características edáficas y su repercusión en los procesos erosivos. En esta región semiárida interactúan el clima, la topografía, el suelo y la cubierta vegetal para determinar el grado de degradación del medio. Desde este punto de vista, el objetivo de este estudio ha sido examinar los componentes edáfico y biológico de los agroecosistemas subsiguientes a la retirada del cultivo cerealista, en los que la cantidad y el tipo de la cubierta vegetal son los que controlan la protección del suelo. Como consecuencia de ello la vegetación es la...

20. Cubiertas vegetales en olivar y viñedo: balance de diez años en relación al agua del suelo y su monitorización - Pastor Piñeiro, Jesús; Benítez, M.; Hernández, A. J.
Abstract Plant covers in olive grove and vineyard: ten years balance in relation to soil water and its monitoring The conceptual framework affects necessary ecológica! engineering for the sustainability of woody cultivations in semiarid Mediterranean environments and tries to articúlate the management of several components of these ecological agroecosystems to optimize soil water without covers irrigation. This report describes ways of managing plant covers ("weeds" or native legumes) in relation to the prevailing rainfall régimen. Over the past 10 years, we have been monitoring soil moisture levéis in an extensive olive plantation and vineyard at different depths under the different plant canopies through standard procedures (gravimetric followed by...

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