149 research outputs found
Collision-dependent power law scalings in 2D gyrokinetic turbulence
Nonlinear gyrokinetics provides a suitable framework to describe
short-wavelength turbulence in magnetized laboratory and astrophysical plasmas.
In the electrostatic limit, this system is known to exhibit a free energy
cascade towards small scales in (perpendicular) real and/or velocity space. The
dissipation of free energy is always due to collisions (no matter how weak the
collisionality), but may be spread out across a wide range of scales. Here, we
focus on freely-decaying 2D electrostatic turbulence on sub-ion-gyroradius
scales. An existing scaling theory for the turbulent cascade in the weakly
collisional limit is generalized to the moderately collisional regime. In this
context, non-universal power law scalings due to multiscale dissipation are
predicted, and this prediction is confirmed by means of direct numerical
simulations.Comment: 7 pages, 5 figures, accepted for publication in Physics of Plasma
Evaluation of soil salinity indexes based on bulk electrical conductivity
[SPA] Los sensores del suelo que miden conductividad eléctrica (CE) y humedad desempeñan un papel esencial en el control de la salinidad del suelo. Sin embargo, la interpretación precisa de la salinidad del suelo depende del desarrollo de Índices de Salinidad (IS) adecuados. Este trabajo se enfoca en el estudio del potencial de varios IS basados en la CE del medio (ECb), utilizando análisis de regresión para conocer cómo estos IS representan la salinidad del suelo. Los resultados indican que el ECb es un IS eficiente siempre que se mida a humedad constante. Además, la precisión de esta medida aumenta con la humedad del sustrato. La pendiente del ajuste de regresión lineal humedad-ECb se propone como un IS nuevo y fiable.
[ENG] Soil sensors that measure electrical conductivity (EC) and moisture play an essential role in monitoring soil salinity. However, the accurate understanding of salinity depends on the development of suitable sensor-based Salinity Indices (SI). This work studied the potential of several SIs based on bulk EC (ECb), which is the only EC directly measured by sensors. Regression studies were performed to know how these SIs describe soil salinity. The results indicate that ECb is an efficient SI as long as humidity is constant. Moreover, its accuracy increases with substrate moisture. The slope of the linear regression fit moisture-ECb is proposed as a novel and reliable SIEsta investigación ha sido financiada por el Ministerio de Ciencia, Innovación y Universidades de España, el Fondo Europeo de Desarrollo Regional, subvención número RTI2018-093997-B-I00, y por la AEI española (subvención número PCI 2019-103608) bajo el programa PRIMA en el marco del proyecto PRECIMED
Liver toxicity and risk of discontinuation in HIV/hepatitis C virus-coinfected patients receiving an etravirine-containing antiretroviral regimen: influence of liver fibrosis
Short communication[Abstract] Objectives. The aim of the study was to establish the risk of liver toxicity in HIV/hepatitis C virus (HCV)-coinfected patients receiving etravirine, according to the degree of liver fibrosis.
Methods. A prospective cohort study of 211 HIV-infected patients initiating an etravirine-containing regimen was carried out. HCV coinfection was defined as a positive HCV RNA test, and baseline liver fibrosis was assessed by transient elastography. Hepatotoxicity was defined as clinical symptoms, or an aspartate aminotransferase (AST) or alanine aminotransferase (ALT) value > 5-fold higher than the upper limit of normal if baseline values were normal, or 3.5-fold higher if values were altered at baseline.
Results. Overall, 145 patients (69%) were HCV coinfected, with a lower nadir (165 versus 220 cells/μL, respectively; p = 0.03) and baseline (374 versus 498 cells/μL, respectively; p = 0.04) CD4 count than monoinfected patients. Etravirine was mainly used with two nucleoside reverse transcriptase inhibitors (129; 61%) or with a boosted protease inhibitor (PI) (28%), with no significant differences according to HCV serostatus. Transient elastography in 117 patients (81%) showed a median (range) stiffness value of 8.25 (3.5–69) kPa, with fibrosis stage 1 in 43 patients (37%) and fibrosis stage 4 in 28 patients (24%). During an accumulated follow-up time of 449.3 patient-years (median 548 days), only one patient with advanced fibrosis (50.8 kPa) had grade 3–4 liver toxicity (0.7%). Transaminases changed slightly, with no significant differences compared with baseline fibrosis, and nine and six patients had grade 1 and 2 transaminase increases, respectively. Also, HCV coinfection was not associated with a higher risk of discontinuation (25% discontinued versus 21% of monoinfected patients; p = 0.39, log-rank test) or virological failure (8% versus 12%, respectively; p = 0.4).
Conclusions. Our data suggest that etravirine is a safe option for HIV/HCV-coinfected patients, including those with significant liver fibrosis
ONTOGENERATION: Reusing Domain and Linguistic Ontologies for Spanish Text Generation
A significant problem facing the reuse of ontologies is to make their content more widely accessible to any potential user. Wording all the information represented in an ontology is the best way to ease the retrieval and understanding of its contents. This article proposes a general approach to reuse domain and linguistic ontologies with natural language generation technology, describing a practical system for the generation of Spanish texts in the domain of chemical substances. For this purpose the following steps have been taken: (a) an ontology in the chemicals domain developed under the METHONTOLOGY framework and the Ontology Design Environment (ODE) has been taken as knowledge source; (b) the linguistic ontology GUM (Generalized Upper Model) used in other languages has been extended and modified for Spanish; (c) a Spanish grammar has been built following the systemic-functional model by using the KPML (Komet-Penman Multilingual) environment. As result, the final system named Ontogeneration permits the user to consult and retrieve all the information of the ontology in Spanish
Composition, distribution, and description of myctophids (Pisces: Myctophidae) found on the Flemish Cap, Northwest Atlantic, during summer 1998
The authors present data regarding the composition, distribution and relative abundance of six species belonging to the Family Myctophidae in the Flemish Cap area, Northwest Atlantic: Lampadena speculigera Goode & Bean, 1896; Benthosema glaciale (Reinhardt, 1837); Myctophum punctatum Rafinesque, 1810; Protomyctophum arcticum (Lütken, 1892); Ceratoscopelus maderensis (Lowe, 1839) and Notoscopelus kroeyerii (Malm, 1861). A review of their distribution in the Atlantic Ocean is also presented, as well as a discussion of the relationship between dominant system currents and their presence on the Flemish Cap.Se describe la composición, distribución y abundancia relativa de seis especies distintas pertenecientes a la familia Myctophidae en Flemish Cap (Atlántico noroeste): Lampadena speculigera Goode & Bean, 1896; Benthosema glaciale (Reinhardt, 1837); Myctophum punctatum Rafinesque, 1810; Protomyctophum arcticum (Lütken, 1892); Ceratoscopelus maderensis (Lowe, 1839) y Notoscopelus kroeyerii (Malm, 1861). Se realiza una revisión de su distribución en el Atlántico y se discute su presencia en Flemish Cap, relacionada con las corrientes dominantes en la zona.Instituto Español de Oceanografí
Ontogeneration: Arquitectura basada en ontologías para la generación de textos en castellano
En este trabajo se presenta Ontogeneration, una arquitectura para generar textos en castellano utilizando ontologías lingüísticas y de dominio con la tecnología KPML de generación de lenguaje natural. Además se ha construido un sistema que genera textos en castellano en el dominio de las sustancias químicas. Para alcanzar tales resultados, se han seguido los siguientes pasos: a) se ha tomado como fuente de conocimiento una ontología en el dominio químico construida usando la metodología de desarrollo de ontologías llamada METHONTOLOGY y el Entorno de Diseño de Ontologías (Ontology Design Environment: ODE), b) se ha extendido y modificado la ontología lingüística GUM (Generalized Upper Model) para el castellano, c) se ha construido una gramática para el castellano siguiendo el modelo sistémico-funcional usando el entorno KPML (Komet Penman Multilingual). Se consigue, así, que los contenidos almacenados en la ontología de dominio sean accesibles por usuarios legos en la materia
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