Modes and the alpha-gamma transition in rf capacitive discharges in N2O at different rf frequencies

This paper reports current-voltage characteristics and pressure-voltage transition curves from the weak-current a-mode to the strong-current g-mode for rf capacitive discharges in N2O at frequencies of 2 MHz, 13.56 MHz, and 27.12 MHz. At 2 MHz the rf discharge is mostly resistive whereas at 13.56 MHz and 27.12 MHz it is mostly capacitive. The weak-current a-mode was found to exist only above a certain minimum gas pressure for all frequencies studied [N. Yatsenko Sov. Phys. Tech. Phys. 26, 678 (19810] previously proposed that the a−g transition corresponds to breakdown of the sheaths. However, we show that this is the case only for sufficiently high gas pressures. At lower pressure there is a smooth transition from the weak-current a-mode to a strong-current g-mode, in which the sheaths produce fast electrons but the sheath has not undergone breakdown

pH prediction in concentrated aqueous solutions under high pressure of acid gases and high temperature

International audienceAn extended model for pH prediction in oil and gas environments has been developed. Accurate pH calculations for high pressure and high temperature applications depends mainly on CO2 and H2S partial pressures, the ionic strength, the chemical composition of the solution, and the temperature. Accounting for the non-ideal behaviors of liquid and gas phases allows pH calculations up to 200 °C, 2000 bar total pressure, and ionic strengths up to 5 mol.L-1. The results are consistent with experimental measurements and with other models reported in the literature

The impact of soil temperature increase on organic matter and faunal properties in a frozen calcareous scree in the French Alps

We examine the effect of natural differences in soil temperature at two locations distant by approximately 500 m in the frozen scree of La Plagne en Chartreuse (Savoy, France). We determined humus properties, soil organisms and biologically mediated soil-forming processes in screes from a low part dominated by an open pine forest (OF, 1100 m asl) and in a top part covered by a dense pine forest (DF, 1200 m asl). Our results show a soil temperature increase of about 3.8 °C in the DF plot during June to October, but similar humus morphology at both plots. Soil pH was lower, and C/N ratio higher in the DF plot. Soil faunal composition differed between DF and OF plots for some taxa. While the abundance of the Oribatid mites was higher, abundance of Collembola was significantly lower in the DF plot. As earthworm activity was scarce at the site, Oribatid mites and Collembola presumably play an important role in the humus microstructure which was confirmed by the analysis of the humus micro-aggregation. To date, changes in the pedofaunal communities did not alter the humus form which may be explained by the complexity of biotic soil interactions and the high functional redundancy of the soil fauna

A 2022 τ\tau-Herculid meteor cluster from an airborne experiment: automated detection, characterization, and consequences for meteoroids

Context. The existence of meteor clusters has long since been a subject of speculation and so far only seven events have been reported, among which two involve less than five meteors, and three were seen during the Leonid storms. Aims. The 1995 outburst of Comet 73P/Schwassmann-Wachmann was predicted to result in a meteor shower in May 2022. We detected the shower, proved this to be the result of this outburst, and detected another meteor cluster during the same observation mission. Methods. The {\tau}-Herculids meteor shower outburst on 31 May 2022 was continuously monitored for 4 hours during an airborne campaign. The video data were analyzed using a recently developed computer-vision processing chain for meteor real-time detection. Results. We report and characterize the detection of a meteor cluster involving 38 fragments, detected at 06:48 UT for a total duration of 11.3 s. The derived cumulative size frequency distribution index is relatively shallow: s = 3.1. Our open-source computer-vision processing chain (named FMDT) detects 100% of the meteors that a human eye is able to detect in the video. Classical automated motion detection assuming a static camera was not suitable for the stabilized camera setup because of residual motion. Conclusions. From all reported meteor clusters, we crudely estimate their occurrence to be less than one per million observed meteors. Low heliocentric distance enhances the probability of such meteoroid self-disruption in the interplanetary space.Comment: 6 pqges, 5 figure

Herpesvirus felino 1 (FHV-1): aislamiento de cepas virales en pacientes felinos con signología ocular y respiratoria

El Herpesvirus felino 1 (FHV-1), perteneciente a la familia Herpesviridae, subfamilia Alphaherpesvirinae, género Varicellovirus produce la rinotraqueitis felina, enfermedad de distribución mundial que afecta a los felinos domésticos y a otros miembros de la familia Felidae. El FHV-1 penetra por las mucosas oronasal y conjuntival y se encuentra asociado a diferentes cuadros clínicos, principalmente respiratorios y oculares. La infección primaria ocurre en felinos desde edades tempranas como el mes de vida y el periodo de incubacion es de de 5-7 días. Luego de la infección, el virus migra a través de las terminaciones nerviosas hasta los ganglios regionales, principalmente el trigémino y permanece allí en estado de latencia. La reactivación viral puede ocurrir con o sin signos clínicos. La infección aguda se caracteriza inicialmente por depresión, hipertermia, anorexia, estornudos y descargas oculonasales serosas que pueden llegar a ser mucopurulentas. La conjuntivitis es la forma de presentación ocular más frecuente. La queratitis herpética es frecuente en felinos adultos y se caracteriza por lisis de las células del epitelio corneal con forma de dendritas llamada “úlcera dendrítica”. La presentación de menor frecuencia es la queratitis estromal que se caracteriza por la opacidad del estroma como consecuencia de un proceso inmunoinflamatorio. La infección podría implicar también al tracto uveal y ha sido relacionada con signos neurológicos. El FHV-1 se asocia también a cuadros de rinosinusitis crónica, aunque su participación en la queratoconjuntivitis seca, queratitis eosinofílica y secuestro corneal, no es tan clara. El diagnóstico se realiza por el hallazgo de signos clínicos y las técnicas de detección directa utilizadas para confirmarlo son PCR y el aislamiento viral (AV). El objetivo de este trabajo fue aislar cepas virales obtenidas a partir de casos clínicos oculares y respiratorios ingresados al Hospital de Clínica de la Facultad de Ciencias Veterinarias de la UNLP.Facultad de Ciencias Veterinaria

Una historia del pensamiento indianista Ukhamawa Jakawisaxa

The objective of this article is to show the contribution that the autobiography os the Aymara leader, Luciano Tapia has made to the official Bolivian history and at the same time to expose the foundations of his indianista thought. The characteristics of his thought deal with the recognition of his own culture, the transposition of Andean notions to an urban context, the imbalance of political praxis with the notion of complementarity of theory and praxis, thought as an event, and ethinicity as a process instead of identity. I have done research in the Archives of the Cámara de Diputados in La Paz and I have consulted academic articles on Andean culture and history.El objetivo de este trabajo es mostrar la aportación de la microhistoria, principalmente a través de la autobiografía del líder político aimara Luciano Tapia, a la historia oficial boliviana y exponer su pensamiento indianista. En éste destacan la revaloración cultural, el replanteamiento de nociones andinas en la urbe, los desajustes entre la práctica política y el principio de complementariedad, el pensar como evento, y la etnicidad en tanto proceso y no como identidad. He consultado los Archivos de la Cámara de Diputados en La Paz y textos académicos sobre la cultura e historia andina