Formaciones edáficas del tramo alto de la cuenca del río Lillas

En la cuenca del río Lillas podemos encontrar junto a suelos propios de áreas de montaña como regosoles y leptosoles, otros comunes en los valles fluviales: los fluvisoles. Los suelos se desarrollan a partir de materiales metamórficos: esquistos, pizarras y cuarcitas —siendo el material fluvial de la misma naturaleza—, bajo una vegetación de pastizal y melojar, en ocasiones sustituido por brezales y jarales. La presencia de permafrost y las subidas de la capa freática limitan el desarrollo de los suelos por lo que se hace muy recomendable su protección.The study about formation of unstable soils, formed from metamorphics rocks (slates, schists, quartzites) has been described in the bowl of Riaza river. The best represented groups of soils are: Leptosols, Regosols and Fluvisols. These soils are really limited and it is higly recomendable to protect them, specially the Fluvisols in recreative zone

Formaciones edáficas del tramo alto de la cuenca del río Riaza

The study about formation of unstable soils that has been developed in a low grade, formed from metamorphics rocks (slates, schists, quartzites) under beechs, oaks, heathers and meadows, in a warm-cold weather, with rains over 1.000 mm, in many diferents slopes, and between 1.300 m and 1.700 m. of highness. The best represented groups of soils are: Leptosols, Regosols, Podzols and Cambisols; with acid pH and, normally, unsatured. In these soils the main changeable cations are Ca2+ and Mg2+; they have sandly textures and high contents in organic matter. These soils are really limited,, it is higly recommendable to protect them.Se estudia la formación de suelos muy inestables, poco desarrollados, derivados de las rocas metamórficas de bajo grado (pizarras, esquistos y cuarcitas) bajo una vegetación de hayedo, melojar, brezal y pradera, y un clima templado frío, con precipitaciones que sobrepasan los 1.000 mm. En pendientes muy variables desde los 1.300 metros hasta los 1.700 metros de altitud. Los grupos de suelos mejor representados son: Leptosoles, Regosoles, Podsoles y Cambisoles, de naturaleza ácida, generalmente desaturados y con Ca2+ y Mg2+ como cationes de cambio mayoritarios, bastante arenosos y ricos en materia orgánica. Estos suelos presentan severas limitaciones por lo que es conveniente su protección

Interactive effects of salinity and temperature on planozygote and cyst formation of Alexandrium minutum (Dinophyceae) in culture

The factors regulating dinoflagellate life-cycle transitions are poorly understood. However, their identification is essential to unravel the causes promoting the outbreaks of harmful algal blooms (HABs) because these blooms are often associated with the formation and germination of sexual cysts. Nevertheless, there is a lack of knowledge on the factors regulating planozygote-cyst transitions in dinoflagellates due to the difficulties of differentiating planozygotes from vegetative stages. In the present study, two different approaches were used to clarify the relevance of environmental factors on planozygote and cyst formation of the toxic dinoflagellate Alexandrium minutum Halim. First, the effects of changes in initial phosphate (P) and nitrate (N) concentrations in the medium on the percentage of planozygotes formed were examined using flow cytometry. Second, two factorial designs were used to determine how salinity (S), temperature (T), and the density of the initial cell inoculum (I) affect planozygote and resting-cyst formation. These experiments led to the following conclusions: 1. Low P/N ratios seem to induce gamete expression because the percentage of planozygotes recorded in the absence of added phosphate (-P) was significantly higher than that obtained in the absence of added nitrogen (-N), or when the concentrations of both nitrogen and phosphate were 20 times lower (N/20 + P/20). 2. Salinity (S) and temperature (T) strongly affected both planozygote and cyst formation, as sexuality in the population increased significantly as salinity decreased and temperatures increased. S, T combinations that resulted in no significant cyst formation were, however, favorable for vegetative growth, ruling out the possibility of negative effects on cell physiology. 3. The initial cell density is thought to be important for sexual cyst formation by determining the chances of gamete contact. However, the inoculum concentrations tested did not explain either planozygote formation or the appearance of resting cysts.Peer reviewe

Utilizing grass for the biological production of polyhydroxyalkanoates (PHAs) via green biorefining: Material and energy flows

The meat and dairy industry across Europe is dependent on the production of grass. However, faced with competing pressures to reduce the environmental impact of agriculture, a potential future reduction of meat and dairy consumption in western diets, and pressure to minimize food production costs, grass could be used to produce alternative products. The biological production of polyhydroxyalkanoates (PHA) by using grass as the primary carbon source in a novel mixed culture process has been studied. A total of 30,000 t of fresh grass would yield approximately 403.65 t of dried biopolymer granules. On the basis of this early stage, non-optimized process, the cumulative energy demand (CED) of PHA produced from waste grass and cultivated grass was found to be 248.4 MJ/kg and 271.8 MJ/kg, respectively, which is the same order of magnitude as fossil-carbon-based polymers. Improvements in volatile fatty acid yields, reduction in chemical and water inputs, and using residues to make other products will reduce the CED. Given the future requirement to produce polymers with little or no fossil-carbon feedstock, an optimized version of the process could provide a viable future production option that also contributes to the long-term sustainability of agricultural communities

The intricacies of dinoflagellate pellicle cysts: The example of Alexandrium minutum cysts from a bloom-recurrent area (Bay of Baiona,NW Spain)

The terms “temporary”, “pellicle,” and “ecdysal” cysts have been employed arbitrarily in the literature of the dinoflagellate life cycle to describe a non-motile and single-layered-wall stage with no mandatory dormancy period, of asexual or sexual origin. These three terms have been used more or less synonymously, but more specific definitions, taking into account morphological and physiological aspects and their roles in dinoflagellate population dynamics, are still needed. To clarify the current terminology, we examine and discuss the usages and foundations of those terms. The background for this discussion is provided by a comparison of the morphology and germination times of three different types of Alexandrium minutum cysts collected during a seasonal bloom in the Bay of Baiona (NW Spain). The double-walled cysts were similar to the resting cysts reported for this species, but other, thin-walled and thecate cysts were also observed. These latter cysts needed between 1 and 17 days to germinate and were therefore considered as short-term cysts, in contrast to the 1.5-month dormancy period of resting (hypnozygotic) cysts. Our results showed that the temporal distribution of these short-term cysts during the bloom period followed a pattern very similar to that of vegetative cells. However, resting cysts were only detected at the end of the bloom. In the context of our present knowledge regarding the dormancy and quiescence of dinoflagellate cysts, “temporary” is a very misleading and uncertain term and must be rejected. The term “ecdysal” has been used in reference to thin-walled cysts when ecdysis has been proved; however, ecdysis is not unique to this type of cysts as thick-walled zygotic cysts can be formed thorough ecdysis of a thecate planozygote. In conclusion, based on our current understanding of cysts, the term “pellicle” more appropriately describes single-layered-wall stages.Versión del editor2,277

Bloom dynamics and life cycle strategies of two toxic dinoflagellates in a coastal upwelling system (NW Iberian Peninsula)

A study of Gymnodinium catenatum and Alexandrium minutum blooms on the Galician coast was conducted from 2005 to 2007 in order to increase knowledge of the mechanisms governing recurrent blooms of these species. Considerable differences in their bloom dynamics were observed. G. catenatum blooms occurred in autumn and winter, following the pattern previously reported in the literature: they began offshore and were advected to the Galician rias when a relaxation of the coastal upwelling occurred. On the other hand, A. minutum blooms developed inside embayments in spring and summer during the upwelling season and were associated with water stability and stratification. Both the vegetative population and the cyst distribution of A. minutum were related to less saline water from freshwater river outputs, which supports a saline-gradient relationship postulated herein for this species. Dinoflagellates may produce both long-term double-walled cysts (resting) and short-term pellicle cysts. Resting cyst deposition and distribution in sediments showed that seeding occurred during the blooms of both species. However, the relationship between the cyst distribution in the sediments in Baiona Bay and the intensity and occurrence of G. catenatum blooms, suggests that the latter are not directly related to resting cyst germination. Moreover, the results presented in the present study point to other difference between the two species, such as the detection of pellicle cysts only for A. minutum. Finally we discuss how the life cycle strategies of these two species may help to explain the different mechanisms of bloom formation reported herein.Versión del editor2,277

EL PAPEL DE LOS TOMILLARES (THYMUS VULGARIS L.) EN LA PROTECCIÓN DE LA EROSIÓN DEL SUELO

The role of Thymus vulgaris formations in the control of erosion problem, in the arroyo de la Vega basin, is the main objectives of this paper. The main representative soil units are: fluvisols, calcisols, regosols, leptosols, gypsisols and cambisols, all developed from miocenic materials. This area is catalogued by local authorities (Comunidad de Madrid), as Significative Erosion Area because there exist an active process of soil erosion. Six plot has been selected according to their environmental and spatial representative and slope degree. In each plot the following data were achieved: abundance/dominant index of every vegetal community, plant cover, number of species, number of individuals of each specie and biomass. In order to evaluate the behaviour of soil against erosion the following features were studied: texture, pH, electrical conductivity, water storage capacity, porosity, density, bulk density, organic carbon, total nitrogen, equivalent calcium carbonate and calcium carbonate extractable in ammonia oxalate. Rainfall test were performed in each plot using a portable rainfall simulator; runoff and sediment yield-out data were obtained. Plots with low biomass show a high runoff and soil losses mean while plots with a high biomass, vegetal diversity and high value of surface stoniness show lower values of runoff and sediment yield-out.Se estudia la influencia de los tomillos vulgares

Cap de Forma (Minorca): la navigazione nel Mediterraneo occidentale dall'età del Bronzo all'età del Ferro: nota preliminare

Nel II Congresso Internazionale di Studi Fenici e Punici, venne presentata una comunicazione sui problemi degli insediamenti litoranei nell'Isola di Minorca, nel loro contesto insulare ed in relazione ad altri simili impianti costieri di Maiorca e delle Pitius. Da quel momento è stato avviato un progetto di studio dei siti archeologici dei siti archeologici delle Isole Baleari, in particolare degli insediamenti costieri, e l'attività sul campo si è concentrata nella ripulitura e nell'inizio del rilevamento grafico delle strutture di Cap de Forma, Maó (2-9 settembre 1991)

Allylic Oxidation of Alkenes Catalyzed by a Copper−Aluminum Mixed Oxide

A strategy for the allylic oxidation of cyclic alkenes with a copper−aluminum mixed oxide as catalyst is presented. The reaction involves the treatment of an alkene with a carboxylic acid employing tert-butyl hydroperoxide as the oxidant. In all cases, the corresponding allylic esters are obtained. When L-proline is employed, the allylic alcohol or ketone is obtained. The oxidation of cyclohexene and valencene has been optimized by design of experiments (DoE) statistical methodology

Acyloxylation of Cyclic Enones: Synthesis of Densely Oxygenated Guaianolides

The α′-acyloxylation of cyclic enones with linear carboxylic acids is described. The reaction is promoted by KMnO4 in the presence of a carboxylic acid and its corresponding carboxylic anhydride. The optimization of the reaction has been carried out using the statistical methodology known as design of experiments. The optimized reaction conditions have been evaluated in terms of substrate scope and compatibility with different functional groups. The methodology has been applied to the synthesis of densely oxygenated guaianes and guaianolides