Ácaros Fitoseidos de las islas Canarias (Acari, Phytoseiidae). II. Tenerife y La Gomera

Phytoseiid mites (Acari, Phytoseiidae) inhabiting plants in natural ecosystems from Tenerife and La Gomera islands (Canary Islands) have been studied. Surveys were conducted from 1997 to 2002. Eleven species were collected, one of them being reported for the first time from the Canary Islands and six of them reported for the first time from Tenerife and La Gomera islands. Euseius machadoi n. sp. collected from woody plants in the Canarian laurisilva is proposed as a new species.En muestreos realizados desde 1997 hasta 2002 se ha estudiado la fauna de ácaros fitoseidos (Acari, Phytoseiidae) asociada a plantas de ecosistemas naturales de las islas de Tenerife y La Gomera (Islas Canarias). Se han recolectado un total de 11 especies, siendo una de ellas citada por vez primera en las islas Canarias y seis de ellas citadas por primera vez en las islas de Tenerife y La Gomera. Euseius machadoi n. sp., recolectado en plantas leñosas de la laurisilva canaria, se propone como una nueva especie

Natural predatory enemies of the erineum strain of Colomerus vitis (Pagenstecher) (Acari, Eriophyidae) found on wild grapevine populations from southern Spain (Andalusia)

The Eurasian wild grapevine, Vitis vinifera L. subspecies sylvestris (Gmelin,) Hegi constitutes a dioecious relative of cultivated grape varieties. It constitutes an important phytogenetic resource, threatened by human activities. The most frequent phytophagous species on this European wild vine is the erineum strain of Colomerus vitis (Pagenstecher) (Acari, Eryophyidae). The aim of the present paper is to identify the natural enemies of the cited mite in wild grapevine populations situated in southern Spain. Results indicated that such kind of predatory biocenosis is integrated by Phytoseiidae (Euseius stipulatus, Kampimodromus sp., Neoseiulella litoralis, Phytoseiulus persimilis, Typhloseiella isotricha, Typhlodromus phialatus, Typhlodromus rhenanoides), Tydeidae (Orthotydeus caudatus,Tydeus caudatus), and dipteran, Cecidomyiidae (Arthrocnodax vitis).

Analysis of electron-positron momentum spectra of metallic alloys as supported by first-principles calculations

Electron-positron momentum distributions measured by the coincidence Doppler broadening method can be used in the chemical analysis of the annihilation environment, typically a vacancy-impurity complex in a solid. In the present work, we study possibilities for a quantitative analysis, i.e., for distinguishing the average numbers of different atomic species around the defect. First-principles electronic structure calculations self-consistently determining electron and positron densities and ion positions are performed for vacancy-solute complexes in Al-Cu, Al-Mg-Cu, and Al-Mg-Cu-Ag alloys. The ensuing simulated coincidence Doppler broadening spectra are compared with measured ones for defect identification. A linear fitting procedure, which uses the spectra for positrons trapped at vacancies in pure constituent metals as components, has previously been employed to find the relative percentages of different atomic species around the vacancy [A. Somoza et al. Phys. Rev. B 65, 094107 (2002)]. We test the reliability of the procedure by the help of first-principles results for vacancy-solute complexes and vacancies in constituent metals.Comment: Submitted to Physical Review B on September 19 2006. Revised version submitted on November 8 2006. Published on February 14 200

Nuclear emulsions for the detection of micrometric-scale fringe patterns: an application to positron interferometry

Nuclear emulsions are capable of very high position resolution in the detection of ionizing particles. This feature can be exploited to directly resolve the micrometric-scale fringe pattern produced by a matter-wave interferometer for low energy positrons (in the 10-20 keV range). We have tested the performance of emulsion films in this specific scenario. Exploiting silicon nitride diffraction gratings as absorption masks, we produced periodic patterns with features comparable to the expected interferometer signal. Test samples with periodicities of 6, 7 and 20 {\mu}m were exposed to the positron beam, and the patterns clearly reconstructed. Our results support the feasibility of matter-wave interferometry experiments with positrons.Comment: 15 pages, 10 figure

Middle eastern genetic legacy in the paternal and maternal gene pools of Chuetas

Chuetas are a group of descendants of Majorcan Crypto-Jews (Balearic Islands, Spain) who were socially stigmatized and segregated by their Majorcan neighbours until recently; generating a community that, although after the seventeenth century no longer contained Judaic religious elements, maintained strong group cohesion, Jewishness consciousness, and endogamy. Collective memory fixed 15 surnames as a most important defining element of Chueta families. Previous studies demonstrated Chuetas were a differentiated population, with a considerable proportion of their original genetic make-up. Genetic data of Y-chromosome polymorphism and mtDNA control region showed, in Chuetas’ paternal lineages, high prevalence of haplogroups J2-M172 (33%) and J1-M267 (18%). In maternal lineages, the Chuetas hallmark is the presence of a new sub-branching of the rare haplogroup R0a2m as their modal haplogroup (21%). Genetic diversity in both Y-chromosome and mtDNA indicates the Chueta community has managed to avoid the expected heterogeneity decrease in their gene pool after centuries of isolation and inbreeding. Moreover, the composition of their uniparentally transmitted lineages demonstrates a remarkable signature of Middle Eastern ancestry—despite some degree of host admixture—confirming Chuetas have retained over the centuries a considerable degree of ancestral genetic signature along with the cultural memory of their Jewish origin.This work was partially supported by grant AAEE246/2014 from the Direcció General de R + D + I (Comu-nitat Autònoma de les Illes Balears) and European Regional Development Fund (ERDF) and FCT, Portuguese Foundation for Science and Tecnology PTDC/ATP-DEM/4545/2012 project financed by European Social Funds (COMPETE-FEDER). We are grateful to Maria Trinidad Garcia (from the Serveis Cientificotècnics of the Uni-versitat de les Illes Balears) for her assistance and help with capillary electrophoresis procedures, María Luz Gómez-Barbeito for her help in mtDNA sequencing and Meryl Wyn Jones for the English language corrections. We would also like to sincerely thank all the people who volunteered to participate in this study

“La tierra no tiene dueño”: Las ligas agrarias correntinas y la lucha por la tierra. Aportes para una discusión.

Since the creation of the Correntinian Agrarian Leagues (CAL) at the beginning of 1972, the matter of the possession of land was acquiring greater significance within the struggle agenda until it was established as the casus belli of the most exacerbated class clashes of the organization. This article investigates the most important of such clashes, which occurred when a group of sharecroppers dedicated to the production of tobacco decided to resist by force the attempts to evict them from the field that theyhad worked for decades. By analyzing a varied corpus of sources (documentaries, newspaper reports, interviews, lyrics, etc.), it seeks to preserve the ‘subversive’ potentialities of the aspirations employed by the rebels. This inquisitive attitude led me to discuss other perspectives developed on the topic revealing, thus, a more complex picture of the conflict than the one restricted by the dichotomy “revolution” - “reaction”/“reformism” that has determined the study of the Agrarian Leagues. Desde la formación de las Ligas Agrarias Correntinas (LAC) a principios de 1972, el problema de la tenencia de la tierra fue adquiriendo mayor centralidad en su agenda de lucha hasta consagrarse como casus belli de los enfrentamientos de clases más exacerbados de la organización. En este artículo se indaga el más importante de esos enfrentamientos, acaecido cuando un grupo de aparceros/as dedicados/as a la producción de tabaco decidió resistir por la fuerza al intento de expulsión del campo que habían laborado por décadas. A partir del recurso a un variado corpus de fuentes (documentales, hemerográficas, entrevistas,letras de canciones, etc.), se busca rescatar las potencialidades ‘subversivas’ de las aspiraciones puestas en juego por los/as agentes rebeldes. Esta actitud inquisitiva me lleva a discutir con otras perspectivas desarrolladas sobre el tópico, revelando una imagen del conflicto más compleja que aquella encorsetada por la dicotomía “revolución” - “reacción”/“reformismo” que ha signado el estudio de las Ligas Agrarias

Rapid kinetics of the interaction between daunomycin and drug-sensitive or drug-resistant P388 leukemia cells

AbstractThe initial stages of the interaction of daunomycin (DNM) with drug-sensitive (P388/S) and drug-resistant (P388/100) cells have been defined by a rapid kinetics stopped-flow procedure. The process can be described by two kinetic components. The faster component accounts for rapid occupation of cell surface sites by DNM, as supported by experiments with liposomes with different surface charge. On the other hand, the effect of verapamil in the assays, suggests that the slower component is involved in the transport of the drug into the cells. Our observations are consistent with a loss in the control of the passive permeability to the drugs in the drug-resistant tumor cells

Positron localization effects on the Doppler broadening of the annihilation line: Aluminum as a case study

The coincidence Doppler broadening (CDB) technique is widely used to measure one-dimensional momentum distributions of annihilation photons, with the aim of obtaining information on the chemical environment of open-volume defects. However, the quantitative analysis of CDB spectra needs to include also purely geometrical effects. A demonstration is given here, on the basis of CDB spectra measured in quenched and in deformed pure aluminum. The comparison of the experimental results with ab initio computations shows that the observed differences come from the difference in free volume seen by positrons trapped in quenched-in vacancies or in vacancylike defects associated to dislocations. The computation reproduces accurately all details of CDB spectra, including the peak near the Fermi break, which is due to the zero-point motion of the confined positron.Peer reviewe

Hole and positron interaction with vacancies and p-type dopants in epitaxially grown silicon

The concentration of vacancies and impurities in semiconductors plays a crucial role in determining their electrical, optical, and thermal properties. This study aims to clarify the nature of the interaction between positrons and ionized p-type impurities, emphasizing the similarities they share with the interaction between holes and this type of impurity. An overall strategy for investigating defects in semiconductor crystals that exhibit a combination of vacancies and p-type impurities is presented. By using positron annihilation spectroscopy, in particular, Doppler broadening of the annihilation radiation, we quantify the concentration of vacancies in epitaxial Si crystals grown by low-energy plasma-enhanced chemical vapor deposition. The vacancy number densities that we find are (1.2 +/- 1.0) x 10(17) cm(-3 )and (3.2 +/- 1.5) x 10(20) cm(-3) for growth rates of 0.27 and 4.9 nm/s, respectively. Subsequent extended annealing of the Si samples effectively reduces the vacancy density below the sensitivity threshold of the positron technique. Secondary ion mass spectrometry indicates that the boron doping remains unaffected during the annealing treatment intended for vacancy removal. This study provides valuable insights into the intricate interplay between vacancies and ionized impurities with positrons in semiconductor crystals. The obtained results contribute to advance the control and understanding of material properties in heterostructures by emphasizing the significance of managing vacancy and dopant concentrations