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(CCMA) Artículos post-print
Mostrando recursos 1 - 20 de 38
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, E.
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, L.; 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...
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, J.
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, J.; 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, J.; 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.
23 de abril de 2010, Día del Libro - Blanco Temprano, Clara María
A finales marzo, principios de abril, empezamos a pensar en el “Día del Libro”, ¡qué bien, este año cae en viernes! Ya es algo tradicional en nuestra biblioteca la celebración del “Día del Libro”.
Vibrational study of dawsonite type compounds MAl(OH)2CO3 (M = Na, K, NH4) - Serna, Carlos J.; García-Ramos, José Vicente; Peña, M. J.
Infrared and Raman spectra of polycrystalline dawsonite type compounds MAl(OH)2CO3 (M = Na, K, NH4) have been obtained between 4000 and 40 cm-1. The data are interpreted on the basis of the factor group analysis of the proposed structures (D28 2h for Na and K dawsonite and D17 2h for NH4 dawsonite). In the dawsonites, lattice vibrational modes are clearly separated from the internal at around 700 cm-1. Most of the internal (OH- and CO2- 3) modes are identified and agree well with theoretical predictions. Vibrations of the OAl unit are responsible for the main features in the 700-250 cm-1...
Identifying elements in rocks from the Dry Valleys desert (Antarctica) by ion beam proton induced X-ray emission - Wierzchos, J.; Ascaso, Carmen; Ager, F. J.; García-Orellana, Isabel; Carmona, Asunción; Respaldiza, M. A.
In some zones of Antarctica’s cold and dry desert, the extinction of cryptoendolithic microorganisms leaves behind inorganic traces of
microbial life. The extinction of these microorganisms is considered to be the best terrestrial analogue of the disappearance of possible life on early Mars. In the present study, sandstone rock samples from several sites of the Dry Valleys known to harbour endolithic microorganisms, as well as samples with microbial fossils, were analysed by proton induced X-ray emission (PIXE). Our findings suggest significant
differences in major element concentrations among the different zones within the same sample. In some sample fractions, these differences could be...
Influence of heavy metal supplementation on specific methanogenic activity and microbial communities detected in batch anaerobic digesters - Milán, Z.; Sánchez Vilches, Enrique; Borja Padilla, Rafael; Montalvo, S.; Ruiz-Tagle, N.; Urrutia, H.; Chamy, R.
Natural and modified zeolites (0.5–1.0 mm) from the Tasajera deposit in Cuba were used to enhance the anaerobic digestion process of synthetic substrates. Natural zeolites were modified by ionic exchange and by adsorption with nickel, cobalt and magnesium. The experiments were carried out by using an inoculum from a full-scale anaerobic reactor treating winery wastewater. Modified natural zeolites not only enhanced the anaerobic digestion process, but also increased the specific methanogenic activity (SMA) of the sludges. The textural and chemical surface characteristics of the modified zeolites were related to the process performance, volatile fatty acid (VFA) production and microbial communities...
Performance evaluation of a two-phase anaerobic digestion process of synthetic domestic wastewater at ambient temperature - Guerrero, L.; Montalvo, S.; Coronado, Eugenio; Chamy, R.; Poirrier, P.; Crutchik, D.; Sánchez, E.; Rubia, M. A. de la; Borja Padilla, Rafael
A two-phase anaerobic digestion process of synthetic domestic wastewater was studied at ambient temperature in mild to cold climates. The hydrolytic stage was carried out in a continuous stirred tank reactor with an effective volume of 1.2 L. The hydrolytic reactor operated at hydraulic retention times (HRTs) in the range of 1.3 to 2.7 h, which allowed for optimum HRT to be obtained in order to achieve a maximum amount of soluble COD. For the methanogenic stage, an up-flow anaerobic filter with a volume of 1.35 L and corrugated plastic rings as biomass immobilization support were used. During the investigation,...
Kinetics of anaerobic degradation of screened dairy manure by upflow fixed bed digesters: Effect of natural zeolite addition - Nikolaeva, S.; Sánchez, E.; Borja Padilla, Rafael; Raposo Bejines, Francisco; Colmenarejo Morcillo, Manuel F.; Montalvo, S.; Jiménez-Rodríguez, A. M.
The effect of the hydraulic retention time (HRT) on the performance of two up-flow anaerobic fixed bed digesters (UFAFBDs) packed with waste tire rubber (D1) and waste tire rubber and zeolite (D2) as micro-organism immobilization supports was studied. It was found that a first-order kinetic model described well the experimental results obtained. The kinetic constants for COD, BOD5, total solids (TS) and volatile solids (VS) removal were determined to be higher in digester D2 than in digester D1 or control. Specifically, they were 0.28 ± 0.01, 0.32 ± 0.02, 0.16 ± 0.01 and 0.24 ± 0.01 d− 1 respectively for...
Molecular features of fossil organic matter in remains of the Lower Cretaceous fern Weichselia reticulata from Przenosza basement (Poland) - Almendros, G.; Zancada, M. C.; González-Vila, Francisco Javier; Lesiak, M. A.; Álvarez Ramis, Concepción
Przenosza (Western Carpathians, Poland) is an important palaeobotanical Cretaceous basement site with morphologically
well-preserved plant remains. Both the morphology of the macro remains and microscopic examination of isolated
plant cuticles reveal species typical of coastal swampy palaeoenvironments, mainly the fern Weichselia reticulata.
After isolation of the plant remains, preliminary characterisation of the fossil organic matter was carried out using
cross-polarization, magic angle spinning (CP-MAS) 13C Nuclear Magnetic Resonance (13C NMR) spectroscopy and
Curie point analytical pyrolysis.
The 13C NMR results suggested a type III kerogen from predominantly terrestrial material which was subjected to
intense diagenetic and catagenetic changes. The prominent resonance at ca. 130 ppm indicates C-...