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(CCMA) Artículos post-print
Mostrando recursos 1 - 20 de 48
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...
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...
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.
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...
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...
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%.
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...
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...
Field evaluation of a decision support system for herbicidal control of Avena sterilis ssp. ludoviciana in winter wheat - González-Andújar, José Luis; Fernández Quintanilla, César; Bastida, F.; Calvo, R.; González Díaz, Lucía; Izquierdo, J.; Lezaún, J. A.; Perea, F.; Sánchez del Arco, M. J.; Urbano, J. M.
Two field studies were conducted in Central and Northern Spain over a total of five seasons to assess the usefulness of a decision support system (AVENA-PC) from agronomic, economic and environmental points of view on herbicidal control of Avena sterilis ssp. ludoviciana in winter wheat. The control treatments evaluated were: (i) AVENA-PC-based recommendations, (ii) full herbicide dose (standard farmer practice), (iii) half herbicide dose and (iv) no herbicide. The herbicide rates used in the AVENA-PC treatment averaged 65% and 30% lower than the full and half dose treatments respectively. AVENA-PC implementation controlled A. ludoviciana with similar efficacy as standard herbicide...
Changes in soil properties and humic substances after long-term amendments with manure and crop residues in dryland farming systems. - Dorado, José; Zancada, M. C.; Almendros, G.; López-Fando, Cristina
After 16 years of periodical applications of either farmyard manure or crop wastes at two levels of mineral N fertilization to a Calcic Haploxeralf in the semiarid central Spain, we found significant changes in chemical fertility levels and in the concentration, chemical composition, and carbon mineralization rates of soil organic matter (SOM). The changes in SOM quality were related to significant improvements of soil physical properties, mainly aggregate stability and water retention. Such changes were related to the increased concentration of humic colloids in soil, the mineral N dose, and the type of organic matter applied. When compared with the...
Transformation of wheat straw in the course of solid-state fermentation by four ligninolytic basidiomycetes - Dorado, José; Almendros, G.; Camarero, S.; Martinez, A. T.; Vares, T.; Hatakka, A.
Biological upgrading of wheat straw by the white-rot fungi Phanerochaete chrysosporium, Pleurotus eryngii, Phlebia radiata, and Ceriporiopsis subvermispora was monitored during 60-day solid-state fermentation. Analysis of straw included determination of weight loss and lignin content, color analysis, and infrared spectroscopy, whereas the studies on the water-soluble fractions were carried out by infrared spectroscopy, elementary analyses and quantification of the total phenols and reducing sugars. The most selective degradation of lignin was produced by P. eryngii and especially by C. subvermispora, the former species releasing the greatest amount of colored water-soluble products, whereas an increase in straw brightness was caused by...
Soil parameters related with the sorption of 2,4-D and atrazine - Dorado, J.; Tinoco, P.; Almendros, G.
In order to explain the retention of 2,4-D and atrazine in fourteen soils from Madrid (central Spain) a series of soil physical and chemical characteristics has been analyzed. Simple and multiple regression models coincided in pointing out that soil abiotic characteristics (physical, mineralogical and cation exchange) comparatively had smaller influence in herbicide sorption than the organic matter. The multiple regression models for 2,4-D suggest that its retention in soil is significantly related with parameters such are the accumulation of particulate organic matter or the proportion of aromatic structures in the humic acids, indicating prevalence of π - πbonding interactions favored...
Molecular characteristics related to the biodegradability of humic acid preparations - Almendros, G.; Dorado, José
The resistance of soil humic material in soil seems to depend on its molecular characteristics. We have studied 12 chemically modified humic samples in mineral soil to identify molecular characteristics connected with their resistance to biodegradation. The treatments, used to introduce changes in the composition, reactivity and N content of the original humic acid (HA), consisted of acetylation, amidation, methylation, nitration, oximation, sulfonation, acid and alkaline hydrolysis, hydrogen peroxide oxidation and fixation of ammonia and of stearic acid. The relations between respirometric data (total mineralization coefficient and mineralization rates at different stages of the 85-day mineralization curve) and a series...
Infrared spectroscopy analysis of hemp (Cannabis sativa) after selective delignification by Bjerkandera sp. at different nitrogen levels - Dorado, José; Almendros, G.; Field, J.A.; Sierra Álvarez, Reyes
Fourier-transform infrared (FT-IR) spectroscopy has been used to monitor changes in C/N-modified lignocellulosic substrates from Cannabis sativa L. in a 7-week solid-state fermentation with the white-rot fungus Bjerkandera sp. strain BOS55. The microbial transformation of hemp was considered as a pretreatment to pulping processes in paper industries. Special emphasis was paid on the N-content of the substrate, which was modified by: (i) external ammonium inputs, (ii) water extraction, and (iii) protease treatment. Selective delignification in the N-limited media was observed. The most diagnostic FT-IR spectral bands in relation to changes in the lignocellulosic substrate were those corresponding to alkyl structures...
Compounds released by sequential chemolysis from cuticular remains of the Cretaceous Gymnosperm Squamastrobus tigrensis (Patagonia, the Argentine) - Almendros, G.; Dorado, José; Sanz, J.; Álvarez Ramis, Concepción; Fernández Marrón, M. T.; Archangelsky, S.
The chemical composition of morphologically well-preserved cuticular remains of the Cretaceous Gymnosperm Squamastrobus tigrensis found in the Bajo Tigre locality (Patagonia) was analysed by a progressive chemical degradation sequence involving: (i) lipid extraction after ultrasonic treatments; (ii) further BF3-MeOH transesterification; and (iii) repeated mild NaBO2-H2O2 degradation of the final residue. The compound assemblages released after the successive treatments were considered to reflect lipid speciation patterns in the different levels of the cuticular structure. In particular, after all the treatments, the dominance of a homologous series of α,ω-alkanedioic acids with maxima at C9 and C10 indicates a polymethylene network based on...
El ozono en la Salud - de la Mata, J.; Felipe Antón, Mª Rosario
[EN]The present review enhances the major importance of
the ozone, both by protecting the life in the Earth, and also by its
medicinal interest, due to the beneficial effect in the treatment of
several diseases. The ozone protects the human health from the
environment contamination and also helps to get over of several
human diseases. The ozone layer (stratospheric ozone) is as a thin
shield, surrounding the Earth and protecting it against the dangerous
sun rays. The ozone is the only substance in the atmosphere
being able to absorb the dangerous ultraviolet radiation (UV-B)
from the sun.
[ES]La presente revisión alude al importante papel del
ozono estratosférico en la protección del...
Estudio limnológico de seis medios leníticos de La Rioja (España) - Soriano, O.; Velasco, José Luis; Álvarez Cobelas, Miguel
[EN] Seasonal limnological samples in six waterbodies from La Rioja (Northern Spain) were taken during a year (july 1996-May 1997). Different saliniry and eutrophication levels were found. 90 phytoplankton,
45 rotifers and 56 macrozoobenthic taxa were identified. All environments weee shallow lakes, lying on a Tertiary valley, most of them experiencing high turbidity. Most phyroplankton algae were new records for the area. Likewise, all macrozoobenthic taxa were new records for La Rioja. Brachionus
leydigi f. tridentatlts (Sernov, 1901), Keratella cochlearis var hispida Lauterborn 1900 and Euchfanis alata Voronkov 1912 were new rotifer records for Spain.