Este artículo de revisión muestra el fundamento teórico de aportes, líneas de investigación y enfoques que existen desde el punto de vista Iberoamericano, con el objetivo de mostrar cuantitativamente ...los principales exponentes iberoamericanos sobre Alfabetización Mediática e Informacional AMI, los resultados son producto de una búsqueda en la WoS, en la categoría Arts & Humanities Citation Index AHCI, con el uso de filtros Media Literacy y Alfabetización Mediática e Informacional, los resultados se almacenan en una base de datos que se depura y luego se analiza en el software bibliométrico VOSviewer. Los tipos de análisis son coautoría, con los métodos Association Strengh y Ling/Long Modularity, la información se presenta en tablas y redes bibliométricas; y se visualiza el nivel de asociación y densidad que existe por autor y país. Los resultados muestran a España con el mayor número de investigadores con publicaciones en revistas de alto impacto con diferentes enfoques sobre la AMI y la incidencia en la sociedad contemporánea desde el ámbito educativo, político, económico y tecnológico; su contribución aúna criterios sobre la necesidad de implementar procesos de enseñanza-aprendizaje con soporte en TIC para innovar el ámbito educativo, ya que los medios digitales no suscitan cambios por sí mismos, es necesaria la colaboración gubernamental en América Latina; los referentes iberoamericanos de la AMI son Ignacio Aguaded, Luis Miguel Romero Rodríguez, Rosa García Ruiz, Amor Pérez Rodríguez.
Cadmium is a heavy metal with carcinogenic properties, highly prevalent in industrialized areas worldwide. Prior reviews evaluating whether cadmium influences breast cancer have been inconclusive and ...not reflected several recent studies.
To evaluate the association between cadmium exposure and female breast cancer incidence, with an emphasis on separately estimating dietary vs. airborne vs. biomarker measures of cadmium and studies published until October 2022.
We evaluated risk of bias using set criteria and excluded one study judged to have high risk based on self-report of breast cancer and insufficient adjustment. We conducted a random effects meta-analysis of epidemiological studies, including subgroups by exposure route and by menopausal status.
A total of 17 studies were eligible for our meta-analysis. Only 2 studies addressed airborne cadmium directly. Breast cancer risk was elevated in women exposed to higher levels of cadmium across all studies − pooled odds ratio: 1.13 (95% confidence interval: 1.00, 1.28), with notable heterogeneity between studies (I2 = 77%). When examining separately by exposure route, dietary cadmium was not linked with an elevated risk – (OR: 1.05; 95%CI: 0.91, 1.21; I2 = 69%), consistent with prior reviews, but biomarker-based studies showed an elevated but non-significant pooled measure (OR: 1.37; 95%CI: 0.96, 1.94; I2 = 84%). We did not observe any clear patterns of different risk by menopausal status.
Findings from our meta-analysis suggest that exposure to higher cadmium increases the risk of breast cancer in women, but with remaining questions about whether non-dietary exposure may be more risky or whether residual confounding by constituents of tobacco smoke may be at play.
•Epidemiological studies have suggested that environmental cadmium exposure increases the risk of breast cancer in women.•This multimedium study identified that higher dietary cadmium exposure does not increase the risk of breast cancer in women.•Analysis by menopausal status and type of medium suggest null associations of cadmium and risk of breast cancer.•Multi-medium approaches may show a complete view of the real impact of environmental exposures on human health.
La Universidad de Málaga –UMA– ha llevado a cabo actividades arqueológicas en el Complexo Arqueológico dos Perdigões, Reguengos de Monsaraz, en el Alentejo portugués desde 2008 a 2016. Se han ...realizado prospecciones geofísicas, excavaciones en extensión y sondeos en diversas estructuras en el Sector L1. El presente trabajo tiene como objetivo discernir las relaciones espacio-temporales entre dos grandes recintos de fosos prehistóricos –F1 y F2–. Metodológicamente, en primer lugar, distinguimos entre cronología –longue durée doxa Braudel– y temporalidad –series B of events in time doxa McTaggart/Ingold–, dos conceptos diferentes pero complementarios para realizar una correcta aproximación histórica al fenómeno de los recintos de fosos. A continuación, basándonos en una extensa serie radiométrica, un examen de sus rellenos y las relaciones entre las estructuras vecinas, identificamos una fase de construcción tardía de esta arquitectura monumental en el tercer cuarto del III milenio a. C. Se reflexiona sobre el empleo de las dataciones radiocarbónicas y los programas estadísticos en contextos tan complejos como los fosos prehistóricos y sus particulares condiciones de colmatación.
Introducción y objetivos: La ubicación taxonómica de las especies de la tribu Potentilleae en Argentina fue muy controvertida e intensamente debatida por varios autores, de tal manera que algunos ...fusionaron géneros, mientras que otros los reconocieron como entidades taxonómicas válidas. Estos conflictos muestran la necesidad de realizar un tratamiento taxonómico actualizado. El objetivo de este trabajo es presentar una sinopsis taxonómica actualizada de las Potentilleae en Argentina.
M&M: Se recopilaron datos taxonómicos de la literatura, incluidos estudios filogenéticos, y se analizaron especímenes de la tribu Potentilleae de herbarios argentinos y extranjeros; además de material colectado a campo.
Resultados y Conclusiones: En Argentina, se reconocieron 3 géneros con 5 especies y 2 formas para la tribu Potentilleae, diferenciándose en una clave dicotómica por caracteres vegetativos, florales y carpológicos. Se legitimó el nombre de los autores de una especie y se lectotipificó una forma. Se amplió la distribución de una especie y se ratificó la presencia de otra. Las Potentilleae habitan en senderos, pastizales, estrato herbáceo de las Yungas, en ambientes descampados y en elevaciones desde los 600-2600 msnm. Crecen en ambientes ribereños y en cultivos abandonados.
Cannabis related online searches are associated with positive attitudes toward medical cannabis, particularly when information is obtained from dispensaries. Since pain is the main reason for ...medicinal cannabis use, information from dispensary websites has the potential to shape the attitude of pain patients towards cannabis. This is relevant because cannabis has demonstrated efficacy in neuropathic pain with low tetrahydrocannabinol (THC) concentrations (< 5-10%), in contrast to potent cannabis (>15% THC), which is highly rewarded in the recreational realm. The role of CBD in pain is not clear, however it has gained popularity. Thus, we hypothesize that the potency of medical cannabis that is advertised online is similar to the cannabis advertised for recreational purposes, which would potentially create a misconception towards medical cannabis. The current lack of knowledge surrounding advertised potencies in the legal cannabis market limits the ability to generate clear policies regarding online advertising to protect patients that are willing to use cannabis for their condition. Thus, we evaluated the advertised THC and CBD content of cannabis products offered online in dispensaries in the United States to determine products' suitability to medicinal use and compare the strength of products offered in legal medical and recreational programs. We recorded THC and CBD concentrations for all herb cannabis products provided by dispensary websites and compared them between or within states. Four Western states (CA, CO, NM, WA) and five Northeastern states (ME, MA, NH, RI, VT) were included. A total of 8,505 cannabis products across 653 dispensaries were sampled. Despite the clear differences between medicinal and recreational uses of cannabis, the average THC concentration advertised online in medicinal programs was similar (19.2% ±6.2) to recreational programs (21.5% ±6.0) when compared between states with different programs, or between medicinal and recreational programs within the same states (CO or WA). Lower CBD concentrations accompanied higher THC products. The majority of products, regardless of medicinal or recreational programs, were advertised to have >15% THC (70.3% - 91.4% of products). These stated concentrations seem unsuitable for medicinal purposes, particularly for patients with chronic neuropathic pain. Therefore, this information could induce the misconception that high potency cannabis is safe to treat pain. This data is consistent with reports in which THC and CBD in products from legal dispensaries or in nationwide products from the illegal market were actually measured, which indicates that patients consuming these products may be at risk of acute intoxication or long-term side effects. Our study offers grounds to develop policies that help prevent misconceptions toward cannabis and reduce risks in pain patients.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
El día 4 de mayo de 2022 se registraron más de 30 sismos en la región de Coquimbo, Chile, algunos de ellos de magnitud 5.0, lo que despertó la preocupación de los habitantes de la zona de Los Vilos y ...alrededores, incluso de otras regiones del país, y la atención por parte de científicos. No obstante, ya desde hace algunos años se viene advirtiendo1 la posibilidad de un gran terremoto en el futuro, precisamente en la misma zona. Como sociedad chilena, se suele decir que estamos acostumbrados a los sismos, y eventualmente cuando sucede una serie de sismos en un periodo breve de tiempo, nos preguntamos si desembocará en un terremoto de mayor magnitud. Si nada ocurre, viene la calma momentánea, y la pregunta puede disiparse. Sin embargo, el monitoreo sísmico es permanente, tanto como la conciencia de que vivimos en un país sísmico ...
Collimated outflows (jets) appear to be a ubiquitous phenomenon associated with the accretion of material onto a compact object. Despite this ubiquity, many fundamental physics aspects of jets are ...still poorly understood and constrained. These include the mechanism of launching and accelerating jets, the connection between these processes and the nature of the accretion flow, and the role of magnetic fields; the physics responsible for the collimation of jets over tens of thousands to even millions of gravitational radii of the central accreting object; the matter content of jets; the location of the region(s) accelerating particles to TeV (possibly even PeV and EeV) energies (as evidenced by
γ
-ray emission observed from many jet sources) and the physical processes responsible for this particle acceleration; the radiative processes giving rise to the observed multi-wavelength emission; and the topology of magnetic fields and their role in the jet collimation and particle acceleration processes. This chapter reviews the main knowns and unknowns in our current understanding of relativistic jets, in the context of the main model ingredients for Galactic and extragalactic jet sources. It discusses aspects specific to active Galactic nuclei (especially blazars) and microquasars, and then presents a comparative discussion of similarities and differences between them.
Se muestra la investigación realizada para la caracterización del comportamiento ante la fricción y desgaste de un acero inoxidable austenítico. Se realizaron ensayos en un tribómetro tipo bola sobre ...anillo con un diseño experimental basado en un arreglo de Taguchi. El material evaluado fue el acero inoxidable AISI 304 y como contraparte se usó el acero AISI 52100. A fin de estudiar la respuesta tribológica, los parámetros (y sus niveles) seleccionados fueron: velocidad de deslizamiento (0,9 m/s y 2 m/s), carga normal (9 N, 19 N y 29 N) y distancias de deslizamiento (500 m, 1000 m y 2000 m). Para las condiciones estudiadas, el coeficiente de fricción resultó en valores promedio entre 0,3227 a 0,9674, donde la carga normal fue el parámetro más influyente. Se obtuvieron valores del coeficiente de desgaste promedio en el intervalo desde 0,000860 a 0,003191. El factor que más afecta el coeficiente de desgaste es la distancia de deslizamiento. El régimen de desgaste se identificó como moderado a severo. El mecanismo de desgaste para el AISI 304 en las condiciones estudiadas fue de adhesión.
A dynamical classification of the cosmic web Forero–Romero, J. E.; Hoffman, Y.; Gottlöber, S. ...
Monthly notices of the Royal Astronomical Society,
July 2009, Letnik:
396, Številka:
3
Journal Article
Recenzirano
Odprti dostop
In this paper, we propose a new dynamical classification of the cosmic web. Each point in space is classified in one of four possible web types: voids, sheets, filaments and knots. The classification ...is based on the evaluation of the deformation tensor (i.e. the Hessian of the gravitational potential) on a grid. The classification is based on counting the number of eigenvalues above a certain threshold, λth, at each grid point, where the case of zero, one, two or three such eigenvalues corresponds to void, sheet, filament or a knot grid point. The collection of neighbouring grid points, friends of friends, of the same web type constitutes voids, sheets, filaments and knots as extended web objects. A simple dynamical consideration of the emergence of the web suggests that the threshold should not be null, as in previous implementations of the algorithm. A detailed dynamical analysis would have found different threshold values for the collapse of sheets, filaments and knots. Short of such an analysis a phenomenological approach has been opted for, looking for a single threshold to be determined by analysing numerical simulations. Our cosmic web classification has been applied and tested against a suite of large (dark matter only) cosmological N–body simulations. In particular, the dependence of the volume and mass filling fractions on λth and on the resolution has been calculated for the four web types. We also study the percolation properties of voids and filaments. Our main findings are as follows. (i) Already at λth= 0.1 the resulting web classification reproduces the visual impression of the cosmic web. (ii) Between 0.2 ≲λth≲ 0.4, a system of percolated voids coexists with a net of interconnected filaments. This suggests a reasonable choice for λth as the parameter that defines the cosmic web. (iii) The dynamical nature of the suggested classification provides a robust framework for incorporating environmental information into galaxy formation models, and in particular to semi–analytical models.
We study the alignment of dark matter haloes with the cosmic web characterized by the tidal and velocity shear fields. We focus on the alignment of their shape, angular momentum and peculiar ...velocities. We use a cosmological N-body simulation that allows us to study dark matter haloes spanning almost five orders of magnitude in mass (109–1014) h
−1 M⊙ and spatial scales of (0.5–1.0) h
−1 Mpc to define the cosmic web. The strongest alignment is measured for halo shape along the smallest tidal eigenvector, e.g. along filaments and walls, with a signal that gets stronger as the halo mass increases. In the case of the velocity shear field only massive haloes >1012 h
−1 M⊙ tend to have their shapes aligned along the largest tidal eigenvector, i.e. perpendicular to filaments and walls. For the angular momentum we find alignment signals only for haloes more massive than 1012 h
−1 M⊙ both in the tidal and velocity shear fields where the preferences is to be parallel to the middle eigenvector; perpendicular to filaments and parallel to walls. Finally, the peculiar velocities show a strong alignment along the smallest tidal eigenvector for all halo masses; haloes move along filaments and walls. The same alignment is present with the velocity shear, albeit weaker and only for haloes less massive than 1012 h
−1 M⊙. Our results show that the two different algorithms used to define the cosmic web describe different physical aspects of non-linear collapse and should be used in a complementary way to understand the cosmic web influence on galaxy evolution.
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