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Digital.CSIC (71,034 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.

(CCMA) Artículos post-print

Mostrando recursos 1 - 20 de 60

1. Introducción. Contaminación y restauración de suelos - Polo, Alfredo; Hernández, Diana; Fritis, Héctor
El suelo es un componente esencial del medio ambiente que tarda miles de años en formarse y que desempeña funciones imprescindibles para el mantenimiento de la vida en la Tierra. El hombre lo usa para fines muy diversos, como obtención de alimentos, extracción de materiales, eliminación de residuos o soporte de construcciones. todas estas actividades pueden afectarle en mayor o menor medida, ocasionando problemas de degradación y pérdida de calidad. Por tanto, el suelo debe considerarse como un recurso no renovable que hay que mantener y proteger. Según la FAO-UNESCO la degradación es "el proceso que rebaja la capacidad actual...

2. Ecobiología de las acumulaciones tobáceas: Los organismos constructores - Souza-Egipsy, Virginia; De los Rios, Asunción; Ascaso, Carmen
Los organismos constructores de las tobas calcáreas. Los microorganismos colonizan todos los ambientes de la Tierra y por tanto su influencia en los ciclos de los elementos en el planeta es indiscutible (Ehrlich, 2002). En el caso de las toba calcáreas, los organismos implicados suelen ser fundamentalmente bacterias y algas (Golubic, 1991, Pentecost and Whitton,2000), aunque también existen importantes interacciones con plantas, hongos e invertebrados acuáticos (Ford and Pedley, 1996). La estructura de las tobas suele variar a lo largo de las estaciones sobre todo en las regiones templadas donde el mayor crecimiento de las capas se produce durante el...

3. Spreading of the invasive Carpobrotus aff. acinaciformis in Mediterranean ecosystems: The advantage of performing in different light environments - Traveset, Anna; Moragues, Eva; Valladares Ros, Fernando
Question: Do specific environmental conditions affect the performance and growth dynamics of one of the most invasive taxa (Carpobrotus aff. acinaciformis) on Mediterranean islands? Location: Four populations located on Mallorca, Spain. Methods: We monitored growth rates of main and lateral shoots of this stoloniferous plant for over two years (2002-2003), comparing two habitats (rocky coast vs. coastal dune) and two different light conditions (sun vs. shade). In one population of each habitat type, we estimated electron transport rate and the level of plant stress (maximal photochemical efficiency Fv/Fm) by means of chlorophyll fluorescence. Results: Main shoots of Carpobrotus grew at...

4. Gender, season and habitat: Patterns of variation in photosynthetic activity, growth and fecundity in Thymelaea velutina - Bandera, Mari Carmen de la; Traveset, Anna; Valladares Ros, Fernando; Gulías, Javier
Changes in the ecophysiological performance of a plant species due to different environmental conditions generally reflect adaptations to the habitat where the plant grows and are often related to its survival capacity in a particular place. We examined this with the dioecious shrub Thymelaea velutina, in two contrasting populations representing the extremes of the altitudinal gradient where the species lives (coastal dunes and mountain habitats over 1000 m). We measured net photosynthetic rates and stomatal conductance, estimated the level of plant stress by chlorophyll fluorescence, and assessed their correlations with growth rate, plant size, flower production and fruit set. We...

5. Degradative studies on a soil humin fraction-sequential degradation of inherited humin - Almendros Martín, Gonzalo; González-Vila, Francisco Javier
Degradation products of soil humin preparations from three different soil types were studied. Inherited humin was isolated by ultrasonic treatment and densimetry of the heavy fraction of soil, and purified by treatment with dilute alkali and acid and exhaustive lipid extraction. These purified humins, which represented 10-26% of the total soil C (34-55% of total alkali-insoluble humified C), were degraded with potassium persulfate followed by alkaline permanganate oxidation. The degradation products obtained (identified by GC-MS as methyl derivatives) were fatty acids, dicarboxylic aliphatic acids, benzenecarboxylic acids, phenolic acids and alkanes. An unexpectedly high proportion of polymethylene compounds (mainly fatty acids) were observed in the humins of the three...

6. Estructura y variabilidad de las nematocenosis en relación con diversos factores biótico y abióticos del medio en una vaguada adehesada del oeste español. - Ibañez, J. J.; Blanco de Pablos, A.; Bello Pérez, Antonio; Revuelta, José L.
[ENG]The edaphic nematocenosis structure on a valley representative of the "dehesas" of Western Spain (Salamanca) has been analyzed. The results verify that the nematode communities in these “silvopastoral" ecosystems occur in spatial mosaics conditioned by vegetation distribution and its microclimatic consequences, as well as by the dynamic of the energy and material fluxes. The composition in trophic groups of nematode communities have intermediate characteristics between the typical forest and pasture lands. In such a way, microbivorous and hacteriophagous appear better represented in woodlands, while the phytophagous are more abundant in open pasturage lands, in direct relation to its biomass. Nematode populations increase their size from higher points in the...

7. Precisiones histológicas y bioquímicas acerca de los ejemplares de Frenelopsis procedentes de Torrelaguna (Madrid ) - Álvarez Ramis, Concepción; Almendros Martín, Gonzalo; Polo, Alfredo
[ES] Son descritos diferentes aspectos morfológicos de los Frenelopsis del yacimiento de Torrelaguna, comparándose sus características con las descritas por otros autores para las especies F. alata y F. oligostomata . Los restos de Frenelopsis presentan, en el yacimiento estudiado, un notable polimorfismo respecto a las dimensiones del fronde; pero todos los ejemplares descritos poseen características muy similares a las de F. oligostomata . El estudio químico de los constituyentes orgánicos de las cutículas muestra una composición compleja, siendo los componentes mayoritarios un residuo cutinizado insoluble en álcalis y una fracción polifenólica extraíble de características similares a los ácidos húmicos....

8. The effect of Chrysoperla carnea (Neuroptera: Chrysopidae) and Adalia bipunctata (Coleoptera: Coccinellidae) on the spread of cucumber mosaic virus (CMV) by Aphis gossypii (Hemiptera: Aphididae) - Garzón, Agustín; Budia, F.; Medina, P.; Morales, I.; Fereres, Alberto; Viñuela, Elisa
The effects of two aphidophagous predators, the larvae of Chrysoperla carnea and adults of Adalia bipunctata, on the spread of cucumber mosaic virus (CMV) transmitted in a non-persistent manner by the cotton aphid Aphis gossypii were studied under semi-field conditions. Natural enemies and aphids were released inside insect-proof cages (1m ×1m ×1 m) with a central CMV-infected cucumber plant surrounded by 48 healthy cucumber seedlings, and the spatiotemporal dynamics of the virus and vector were evaluated in the short and long term (1 and 5 days) in the presence and absence of the natural enemy. The spatial analysis by distance indices methodology together with other indices measuring the...

9. Biofertilization of Degraded Southern African Soils with Cyanobacteria Affects Organic Matter Content and Quality - Pardo, Mª Teresa; Almendros Martín, Gonzalo; Zancada Fernández, M. Cristina; López-Fando, Cristina
We studied, under laboratory conditions, the effects of Nostoc 9v (cyanobacteria) on the soil organic matter (SOM) content and quality of different soils from Tanzania, Zimbabwe, and South Africa. Soils were inoculated with Nostoc 9v at a rate of 5mg dry biomass g 1 soil and incubated for 3 months at 27 C under 22Wm 2 illumination for 16 h and 8 h under darkness. Moisture content was maintained at 60% of field capacity. The composition of the SOM and the structural features of the humic acid (HA) fraction were studied by visible and infrared (IR) spectroscopies. Nostoc 9v proliferated and colonized the surfaces of all soils...

10. 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...

11. Locating water in the dehydrated thallus of lichens from extreme microhabitats (Antárctica) - Ascaso, Carmen; Souza-Egipsy, Virginia; Sancho, Leopoldo G.
Microbial ecology deals with interactions among microorganisms, between microorganisms and their environment, and with water relations in the microhabitat. In the desiccated state, many lichens tolérate long periods of intense stress. The present report describes the use of scanning electrón microscopy with backscattered electrón imaging (SEM-BSE) to observe - on the spatial nanometer scale - relationships among the epilithic thallus of an Antarctic Lichen, microorganisms belonging to epilithic, chasmoendolithic and cryptoendolithic communities and minerals. The main aim of the study was to determine the precise location of minute quantities of water that the thallus may maintain probably obtained from the mineral microenvironment of its rock habitat. Through low...

12. Molecular proxies in free lipid and humic acid perborate degradation compounds for the assessment of the impact of clearing and cultivating Central Spain forest soils - Tinoco, P.; Piedra Buena, A.; Zancada, M. C.; Sanz Perucha, Jesús; Almendros, G.
Perborate degradation yielded information on the amounts of the different carbon forms accumulated in soils, whereas FSLS included valuable signature compounds suggesting changes in organisms and processes after clearing.

13. Producción y gestión del compost - Negro, M. J.; Villa, F.; Aibar, J.; Aracón, R.; Ciria, P.; Cristóbal, M. V.; Benito, A. de; García Martín, A.; Garcia Muriedas, G.; Labrador, C.; Lacasta Dutoit, Carlos; Lezaún, J. A.; Meco, R.; Pardo, Gabriel; Solano, M. L.; Torner, C.; Zaragoza, C.
El compostaje es un proceso biológico aerobio, que bajo condiciones de aireación, humedad y temperaturas controladas y combinando fases mesófilas (temperatura y humedad medias) y termófilas (temperatura superior a 45ºC), transforma los residuos orgánicos degradables, en un producto estable e higienizado, aplicable como abono o sustrato. Es decir, el compostaje es: - una técnica de estabilización y tratamiento de residuos orgánicos biodegradables. El calor generado durante el proceso (fase termófila) va a destruir las bacterias patógenas, huevos de parásitos y muchas semillas de malas hierbas que pueden encontrarse en el material de partida, dando lugar a un producto higienizado. - una técnica biológica de reciclaje de materia orgánica...

14. Spatial dynamics of a Sorghum halepense population in a maize monoculture - Fernández Quintanilla, César; Dorado, José; Hernaiz, P.; Andújar, Dionisio
Sorghum halepense is a perennial plant very common in most Spanish maize fields. The typical aggregated distribution of this weed and the high cost of the post emergence herbicides required for its control makes it an ideal target for site-specifc weed management. The objective of sizes and shapes of S.halepense patches and the time evolution of these patches under standard agronomic practices.

15. Sorption-Desorption of Alachlor and Linuron in a Semiarid Soil As Influenced by Organic Matter Properties after 16 Years of Periodic Inputs - Dorado, José; López-Fando, Cristina; Zancada, M. C.; Almendros, G.
The effect of management practices on soil potential for regulating the residual concentration of pesticides was examined in samples from a Calcic Haploxeralf in Toledo (central Spain). Sorptiondesorption of alachlor and linuron was found to depend on inputs of lignocelullosic wastes or cattle manure for the past 16 years. For a given herbicide, the soil sorption capacity (K f) follows the order control < crop residues < manure, which is consistent with the organic C content in the soil samples. Some structural characteristics of the soil humic acid as revealed by visible and infrared spectroscopies and analytical pyrolysis were useful to forecast the sorption-desorption intensity. Simple and...

16. El orden alfisol en la Isla Gran Canaria - Sánchez-Díaz, J.; Guerra-Delgado, A.; Fernández-Caldas, E.

17. Self-shading in cork oak seedlings: Functional implications in heterogeneous light environments. Acta Oecologica - Esteso-Martínez, J.; Peguero Pina, José Javier; Valladares, Fernando; Morales Iribas, Fermín; Gil-Pelegrín, Eustaquio
The high self-shading found in Quercus suber seedlings has been interpreted as a feature common for plants growing in high light environments. But many studies reveal that Q. suber has high survival rates under low-light conditions, so a high degree of self-shading could be the consequence of a foliage composed of many small leaves, with no drawbacks for coping with low light. A characterization of the light environment in a Q. suber stand together with a study of photosynthetic parameters of full sunlight-exposed (FSLE) and self-shaded (SS) leaves were carried out to tackle this apparent contradiction. Although the number of...

18. Biological sulphate removal in acid mine drainage using anaerobic fixed bed reactors with cheese whey as a carbon source - Jiménez-Rodríguez, A. M.; Durán-Barrantes, M. M.; Borja Padilla, Rafael; Sánchez, E.; Colmenarejo Morcillo, Manuel F.; Raposo Bejines, Francisco
The effect of the hydraulic retention time and the sulphate-total COD ratio on the performance of an anaerobic biological process applied to acid mine drainage water (AMD) was evaluated using cheese whey as a carbon source. Laboratoryscale fixed bed bioreactors operating at 25 ± 2 ºC were used in the experiments. Maximum sulphate reduction and hydrogen sulphide production were achieved at a hydraulic retention time of 8 days and at a sulphate-total COD ratio of 0.5. Under these conditions, the sulphate removal was found to be 68.1% while the hydrogen sulphide production was 0.27 L/day. At the same time, the total COD removal obtained was 55.4%.

19. Growth of stoichiometric and textured LiNbO3 films on Si by pulsed laser deposition - Chaos, J. A.; Gonzalo de los Reyes, José; Afonso, Carmen N.; Perriére, J.; García González, María Teresa
Laser ablation of single-crystal LiNbO3 in a gas environment is used to grow films on (100) Si substrates heated to 650 °C. The film composition and crystallinity are studied as a function of the nature (reactive, O2, or inert, Ar) and pressure of the gas environment applied during deposition and cooling-down processes, the laser energy density and the target-substrate distance. Experimental results show that a gas pressure close to 1 mbar is required to produce stoichiometric films in either O2 or Ar. The modification of the laser energy density and the target-substrate distance allows us to improve the crystallinity of...

20. Fluctuations in plant populations: Role of exogenous and endogenous factors - Hernández Plaza, María Eva; Navarrete, Luis; Lacasta, Carlos; González-Andújar, José Luis
Question: What is the role of exogenous and endogenous factors in determining fluctuations in plant populations? Methods: A total of 29 long-term time series from different plant species was analysed. Data were obtained from the literature as well as from our own surveys. For each series we calculated the autocorrelation function to identify the presence of cyclic dynamics. The existence and the order of density-dependent processes were examined by calculating the partial rate correlation function to obtain the global Lyapunov exponent to assess whether populations exhibited chaotic dynamics. To test the effect of exogenous factors on each population, we used...

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