La Cobertera vegetal en el olivar : un método de producción agroecológico

Les actuals pràctiques agrícoles són un factor que contribueix a la degradació del medi ambient i de l'espai natural. A fi de pal_liar aquesta situació, la Comunitat Europea, a través del Consell d'Europa, ha produit una sèrie de normes que regeixen la política agrària comunitària (PAC) actual. En aquest treball s'estudia un mètode de producció que té com a fi protegir el medi ambient i restablir l'equilibri ecològic a les zones afectades. Aquest mètode, conegut com no-conreu amb coberta vegetal, consisteix en mantenir el sòl dins la zona corresponent a la copa de l'olivera amb una aplicació d'herbicida cada any, mentres es deixen crèixer les males herbes a la resta de terreny, controlant-les amb escardes periòdiques. El mètode es avantatjós per a l'economia de l'agricultor i per al medi natural en el que es troba. car per un cantó es redueixen els costos de collita, maquinària, adobs, etcètera i per altra banda el sistema no perjudica el medi, ja que frena el procès erosiu, augmenta la infiltració del sòl, redueix l'escorriment, no destrueix l'estructura edàfica, etc. etcLas actuales prácticas agrícolas constituyen un factor que contribuye a la degradación del medio ambiente y del espacio natural. Para paliar esta situación la Comunidad Europea a través del Consejo de Europa ha elaborado una serie de normas que rigen la actual política agraria comunitaria (PAC). Aquí se estudia un método de producción que creemos que se aproxima bastante a dicha normativa comunitaria, cuya finalidad es salvaguardar el medio ambiente y restablecer el equilibrio ecológico en las zonas afectadas. Este método denominado no laboreo con cobertera vegetal consiste en la realización de suelos en la zona que corresponde a la proyección de la copa del olivo con aplicación anual de herbicida, y en el resto del terreno se dejan crecer las malas hierbas y su desarrollo es controlado al ser desbrozadas periódicamente. Hasta el momento este método es ventajoso para la economía del agricultor y para el medio natural en el que se inscribe, ya que por un lado se reducen los costes de recolección, maquinaria, abonado, etc. y por otro lado el sistema no perjudica al medio ya que frena el proceso erosivo, aumenta la infiltración del suelo, reduce la escorrentía, no se destruye la estructura edáfica, etc

El cerdo Pelón Mexicano: programa de conservación genética de una raza en peligro

Here is described the programme of genetic conservation of the Mexican Hair-less pig under development in the Yukatan State (Mexico). It consists of several actions on the characterization of the population and its management system, the in situ and ex situ conservation, and the coordination. The results obtained by the moment are summarized.Aquí se describe el programa de conservación genética del cerdo Pelón Mexicano en desarrollo en el Estado de Yukatan (México). Consiste en varias acciones sobre la caracterización de la población y de sus sistemas de explotación, la conservación in situ y ex situ y la coordinación. Se resumen los resultados obtenidos hasta el momento

Variable order Mittag-Leffler fractional operators on isolated time scales and application to the calculus of variations

We introduce new fractional operators of variable order on isolated time scales with Mittag-Leffler kernels. This allows a general formulation of a class of fractional variational problems involving variable-order difference operators. Main results give fractional integration by parts formulas and necessary optimality conditions of Euler-Lagrange type.Comment: This is a preprint of a paper whose final and definite form is with Springe

Potencial redox en suelos de la zona de Cabo de Gata (Almería)

En el presente trabajo estudiamos la relación entre el potencial redox y una serie de factores que lo condicionan, en un total de ocho perfiles procedentes de la zona de Cabo de Gata (Almeria) y desarrollados todos ellos sobre roca caliza o rica en carbonato cálcico bajo clima subdesérticocálido. Encontramos que el valer del Eh está relacionado con los contenidos en materia orgánica y manganeso y con el valor del pH, en cambio no guarda relación con el contenido en hierro.In the present papel' we study the relationship among redox potential and some of the factors that they condition it, in eight soil profils from Cabo de Gata región (Almeria-Spain), all them al'e developed on limestone or other richo in calcium carbonate, rocks. The climate is warm subdesertic. We found the Eh value Eh related with the amounts of organic matter and manganese and the pH value. The Eh value is not related with the iron content

Neutrino physics at large colliders

Large colliders are not sensitive to light neutrino masses and character, but they can produce new heavy neutrinos, allowing also for the determination of their Dirac or Majorana nature. We review the discovery limits at the next generation of large colliders.Comment: LaTeX 32 pages. This review summarises and extends work presented at several conferences. To appear in the proceedings of CORFU2005. References adde

Chemoselective Preparation of New Families of Phenolic-Organoselenium Hybrids—A Biological Assessment

Being aware of the enormous biological potential of organoselenium and polyphenolic compounds, we have accomplished the preparation of novel hybrids, combining both pharma-cophores in order to obtain new antioxidant and antiproliferative agents. Three different families have been accessed in a straightforward and chemoselective fashion: carbohydrate-containing N-acylisoselenoureas, N-arylisoselenocarbamates and N-arylselenocarbamates. The nature of the organoselenium framework, number and position of phenolic hydroxyl groups and substituents on the aromatic scaffolds afforded valuable structure–activity relationships for the biological as-says accomplished: antioxidant properties (antiradical activity, DNA-protective effects, Glutathione peroxidase (GPx) mimicry) and antiproliferative activity. Regarding the antioxidant activity, selenocar-bamates 24–27 behaved as excellent mimetics of GPx in the substoichiometric elimination of H2O2 as a Reactive Oxygen Species (ROS) model. Isoselenocarbamates and particularly their selenocarbamate isomers exhibited potent antiproliferative activity against non-small lung cell lines (A549, SW1573) in the low micromolar range, with similar potency to that shown by the chemotherapeutic agent cisplatin (cis-diaminodichloroplatin, CDDP) and occasionally with more potency than etoposide (VP-16).Ministerio de Ciencia e Innovación PID2020-116460RB-I00Junta de Andalucía FQM134Gobierno de las Islas Canarias ProID202001010

Theories for the Fermi Scale

I give a short review of our present understanding of new theories of the electroweak scale, with emphasis on recent progress. Plenary talk at the EPS 2007 Conference at Manchester.Comment: 14 pages, EPS 2007 Conferenc

The Ring Imaging Cherenkov detector (RICH) of the AMS experiment

The Alpha Magnetic Spectrometer (AMS) experiment to be installed on the International Space Station (ISS) will be equipped with a proximity focusing Ring Imaging Cherenkov (RICH) detector for measuring the electric charge and velocity of the charged cosmic particles. A RICH prototype consisting of 96 photomultiplier units, including a piece of the conical reflector, was built and its performance evaluated with ion beam data. Preliminary results of the in-beam tests performed with ion fragments resulting from collisions of a 158 GeV/c/nuc primary beam of Indium ions (CERN SPS) on a Pb target are reported. The collected data included tests to the final front-end electronics and to different aerogel radiators. Cherenkov rings for a large range of charged nuclei and with reflected photons were observed. The data analysis confirms the design goals. Charge separation up to Fe and velocity resolution of the order of 0.1% for singly charged particles are obtained.Comment: 29th International Conference on Cosmic Rays (Pune, India

The AMS-02 RICH Imager Prototype - In-Beam Tests with 20 GeV/c per Nucleon Ions -

A prototype of the AMS Cherenkov imager (RICH) has been tested at CERN by means of a low intensity 20 GeV/c per nucleon ion beam obtained by fragmentation of a primary beam of Pb ions. Data have been collected with a single beam setting, over the range of nuclear charges 2<Z<~45 in various beam conditions and using different radiators. The charge Z and velocity beta resolutions have been measured.Comment: 4 pages, contribution to the ICRC 200

The AMS-RICH velocity and charge reconstruction

The AMS detector, to be installed on the International Space Station, includes a Ring Imaging Cerenkov detector with two different radiators, silica aerogel (n=1.05) and sodium fluoride (n=1.334). This detector is designed to provide very precise measurements of velocity and electric charge in a wide range of cosmic nuclei energies and atomic numbers. The detector geometry, in particular the presence of a reflector for acceptance purposes, leads to complex Cerenkov patterns detected in a pixelized photomultiplier matrix. The results of different reconstruction methods applied to test beam data as well as to simulated samples are presented. To ensure nominal performances throughout the flight, several detector parameters have to be carefully monitored. The algorithms developed to fulfill these requirements are presented. The velocity and charge measurements provided by the RICH detector endow the AMS spectrometer with precise particle identification capabilities in a wide energy range. The expected performances on light isotope separation are discussed.Comment: Contribution to the ICRC07, Merida, Mexico (2007); Presenter: F. Bara