Fermionic field perturbations of a three-dimensional Lifshitz black hole in conformal gravity

We study the propagation of massless fermionic fields in the background of a three-dimensional Lifshitz black hole, which is a solution of conformal gravity. The black hole solution is characterized by a null dynamical exponent. Then, we compute analytically the quasinormal modes, the area spectrum, and the absorption cross section for fermionic fields. The analysis of the quasinormal modes shows that the fermionic perturbations are stable in this background. The area and entropy spectrum are evenly spaced. At the low frequency limit, it is observed that there is a range of values of the angular momentum of the mode that contributes to the absorption cross section, whereas it vanishes at the high frequency limit. In addition, by a suitable change of variables a gravitational soliton can also be obtained and the stability of the quasinormal modes are studied and ensured.Comment: 14 pages; 3 figures. arXiv admin note: text overlap with arXiv:1407.639

High yield and high quality DNA from vegetative and sexual tissues of Mexican white pine (Pinus ayacahuite)

Pines are considered to be difficult for DNA extraction. However, from one species to the other there is variation in phenolic profiles and seed size that might affect final DNA yields and quality. Two DNA extraction protocols (CTAB and SDS based) were compared for their ability to produce DNA on leaves, gametophyte and embryo from Pinus ayacahuite, a pine species with a large seed (8 - 18 mm). The DNA obtained from both procedures was quantified and tested by PCR. The CTAB protocol provided higher DNA yields from vegetative tissue and embryo than the SDS method. Embryos (2n) and gametophytes (n) proved to be very good sources of DNA and the DNA isolated was suitable for PCR-RAPD and SSRmarkers. This paper reports the results and describes the modified CTAB protocol

Self-adhesive flowable composite-resin as a fissure sealant. A microleakage study

Indexación: Web of Science; ScieloRESUMEN Objetivo: Evaluar la capacidad de sellado de una resina fluida autoadhesiva (Fusio Liquid Dentin, Pentron Clinical) utilizada como sellante de fosas y fisuras con distintos acondicionamientos de la superficie de esmalte. Materiales y Métodos: Se seleccionaron 140 terceros molares recientemente extraídos, los que fueron distribuidos aleatoriamente en cuatro grupos (n=35) y recibieron una técnica de acondicionamiento del esmalte y aplicación de un sellante. Se establecieron los siguientes grupos: Grupo 1, grabado ácido y aplicación de sellante (Clinpro, 3M ESPE); Grupo 2, grabado ácido y aplicación de resina autoadhesiva (Fusio Liquid Dentin, Pentron Clinical); Grupo 3, aplicación de resina autoadhesiva; Grupo 4, microarenado del esmalte y aplicación de resina autoadhesiva. Los dientes sellados fueron termociclados (500 ciclos, 5-55°C), y posteriormente sumergidos en solución de nitrato de plata amoniacal por 24 h (pH=14) y luego en revelador radiográfico (GBX, Kodak) por 8h. Posteriormente, los dientes fueron cortados para obtener 2 láminas por diente que fueron observadas bajo magnificación (4x) y analizadas digitalmente para evaluar la microinfiltración y la penetración en la fisura. Los resultados fueron analizados estadísticamente (ANOVA, Dunnett, p<0.05). Resultados: La microinfiltración del Grupo 1 (13.18 ± 9.25%) fue significativamente menor que la de los grupos 2, 3 y 4 (p<0.05). La penetración en la fisura en el Grupo 1 (98.92 ± 2.77%) fue mayor que en los otros grupos, siendo esta diferencia significativa sólo con el Grupo 4. Conclusión: Fusio Liquid Dentin tiene una capacidad de sellado inferior a la del sellante convencional Clinpro, independiente del acondicionamiento del esmalte que se utilice.ABSTRACT Aim: To evaluate the sealing ability of a self-adhesive flowable composite-resin (Fusio Liquid Dentin, Pentron Clinical) with different conditioning treatments of the enamel surface used as a fissure sealant. Materials and Method: 140 recently extracted human third molars were selected and randomly divided into four groups (n=35). Each group received an enamel conditioning treatment and a sealant application. The following groups were established: Group 1, acid etching and sealant application (Clinpro, 3M ESPE); Group 2, acid etching and self-adhesive flowable composite-resin (Fusio Liquid Dentin, Pentron Clinical); Group 3, self-adhesive flowable composite-resin; Group 4, sandblasting and self-adhesive flowable composite-resin. Sealed teeth were thermocycled (500 cycles, 5-55ºC) and immersed in ammoniacal silver nitrate solution for 24 h (ph=14). After that, the teeth were immersed in radiographic developer solution (GBX, Kodak) for 8 h. Then, the teeth were vertically sectioned to obtain two slides each that were observed under magnification (4x) and digitally analyzed to assess microleakage and sealant penetration. Results were statistically analyzed (ANOVA, Dunnett, p<0.05). Results: Microleakage of Group 1 (13.18 ± 9.25%) was significantly lower than groups 2, 3 and 4 (p<0.05). Group 1 had the highest sealant penetration mean (98.92 ± 2.77%). Conclusion: Fusio Liquid Dentin had a worse sealing ability than Clinpro irrespective of their enamel conditioning treatment when used as a fissure sealant. Among Fusio’s groups, acid etching was the best enamel surface conditioning treatment.http://www.scielo.cl/pdf/piro/v6n1/art01.pd

Latitudinal extension of low-latitude scintillations measured with a network of GPS receivers

International audienceA latitudinal-distributed network of GPS receivers has been operating within Colombia, Peru and Chile with sufficient latitudinal span to measure the absolute total electron content (TEC) at both crests of the equatorial anomaly. The network also provides the latitudinal extension of GPS scintillations and TEC depletions. The GPS-based information has been supplemented with density profiles collected with the Jicamarca digisonde and JULIA power maps to investigate the background conditions of the nighttime ionosphere that prevail during the formation and the persistence of plasma depletions. This paper presents case-study events in which the latitudinal extension of GPS scintillations, the maximum latitude of TEC depletion detections, and the altitude extension of radar plumes are correlated with the location and extension of the equatorial anomaly. Then it shows the combined statistics of GPS scintillations, TEC depletions, TEC latitudinal profiles, and bottomside density profiles collected between September 2001 and June 2002. It is demonstrated that multiple sights of TEC depletions from different stations can be used to estimate the drift of the background plasma, the tilt of the plasma plumes, and in some cases even the approximate time and location of the depletion onset. This study corroborates the fact that TEC depletions and radar plumes coincide with intense levels of GPS scintillations. Bottomside radar traces do not seem to be associated with GPS scintillations. It is demonstrated that scintillations/depletions can occur when the TEC latitude profiles are symmetric, asymmetric or highly asymmetric; this is during the absence of one crest. Comparison of the location of the northern crest of the equatorial anomaly and the maximum latitude of scintillations reveals that for 90% of the days, scintillations are confined within the boundaries of the 50% decay limit of the anomaly crests. The crests of the anomaly are the regions where the most intense GPS scintillations and the deepest TEC depletions are encountered. In accord with early results, we observe that GPS scintillations/TEC depletions mainly occur when the altitude of the magnetic equator F-region is above 500km. Nevertheless, in many instances GPS scintillations and TEC depletions are observed to exist when the F-layer is well below 500km or to persist when the F-layer undergoes its typical nighttime descent. Close inspection of the TEC profiles during scintillations/depletions events that occur when the equatorial F-layer peak is below 500km altitude reveals that on these occasions the ratio of the crest-to-equator TEC is above 2, and the crests are displaced 10° or more from the magnetic equator. When the equatorial F-layer is above 500km, neither of the two requirements is needed, as the flux tube seems to be inherently unstable. We discuss these findings in terms of the Rayleigh-Taylor instability (RTI) mechanism for flux-tube integrated quantities. We advance the idea that the seeming control that the reverse fountain effect exerts on inhibiting or suppressing GPS scintillations may be related to the redistribution of the density and plasma transport from the crests of the anomaly toward the equatorial region and then to much lower altitudes, and the simultaneous decrease of the F-region altitude. These two effects originate a decrease in the crest/trough ratio and a reduction of the crests separation, making the whole flux tube more stable to the RTI. The correspondence between crest separation, altitude of the equatorial F-region, the onset of depletions, and the altitude (latitude) extension of plumes (GPS scintillations) can be used to track the fate of the density structures

Nematicidal activity of essential oils and organic amendments from Asteraceae against root-knot nematodes

The essential oil of Chrysanthemum coronarium flowerheads showed strong nematicidal activity in vitro and in growthchamber experiments. Essential oil concentrations of 2, 4, 8 and 16 μL mL−1, significantly reduced hatch, J2 survival (determined by final value and area under curves of cumulative percentage hatch or mortality) and reproduction rate of Meloidogyne artiellia in vitro, with the lowest values occurring at 16 μL mL−1. In pot trials with chickpea cv. PV 61, essential oil concentrations of 10–40 μL per 500 cm3 soil, applied on sterile cotton pellets, also significantly reduced the nematode’s reproduction rate. The biological processes of mortality and hatching/reproduction were adequately described by the monomolecular and expanded negative exponential models, respectively. Effectiveness of soil amendment with either flowers, leaves, roots or seeds of C. coronarium, and flowers from several species of Asteraceae (Chrysanthemum segetum, Calendula maritima, Calendula officinalis and Calendula suffruticosa) at 5 g per 500 cm3 soil was tested for suppression of M. artiellia and growth of chickpea cv. PV 61 under growth-chamber conditions. In these tests, flowers of all five Asteraceae species and various parts of C. coronarium significantly reduced reproduction rates of M. artiellia, by 83·0–95·9%, with the minimum rates occurring in infected chickpea plants amended with flowers of C. officinalis and C. suffruticosa. The in vitro and in planta results suggest that the essential oil of C. coronarium and organic amendments from Asteraceae species may serve as nematicides.This research, part of a PhD study by P.P., was supported by grant SC98-022 and a fellowship from the Instituto Nacional de Tecnologías Agroalimentarias (INIA).Peer reviewe