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.
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.
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.
The bacterial cell envelope, in particular the cell wall, is considered the main controlling factor in the biosorption of aqueous uranium(vi) by microorganisms. However, the specific roles of the ...cell wall, associated biomolecules, and other components of the cell envelope are not well defined. Here we report findings on the biosorption of uranium by isolated cell envelope components and associated biomolecules, with P. putida 33015 and B. subtilis 168 investigated as representative strains for the differences in Gram-negative and Gram-positive cell envelope architecture, respectively. The cell wall and cell surface membrane were isolated from intact cells and characterised by X-ray Photoelectron Spectroscopy (XPS) and Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FT-IR) spectroscopy; revealing variations in the abundance of functional moieties and biomolecules associated with components of the cell envelope. Uranium biosorption was investigated as a function of cell envelope component and pH, comparing with intact cells. The isolated cell wall from both strains exhibited the greatest uranium biosorption capacity. Deprotonation of favourable functional groups on the biomass as the pH increased from 3 to 5.5 increased their uranium biosorption capacity by approximately 3 fold. The results from ATR-FT-IR indicated that uranium(vi) biosorption was mediated by phosphate and carboxyl groups associated with proteins and phosphorylated biopolymers of the cell envelope. This includes outer membrane phospholipids and LPS of Gram-negative bacteria and teichoic acids, surface proteins and peptidoglycan from Gram-positive bacteria. As a result, the biosorption process of uranium(vi) to microorganisms is controlled by surface interactions, resulting in higher accumulation of uranium in the cell envelope. This demonstrates the importance of bacterial cell wall as the key mediator of uranium biosorption with microorganisms.
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.
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.
A comparative study of a wide collection of sepiolites (22 samples from different locations, including samples coming from the greatest deposits of sepiolite in the world) was made with the aim of ...understanding the real variability of the surface properties in sepiolite. The samples have been studied by XRD, Electron Microscopy (TEM and SEM) and the adsorption–desorption of N2. The influence of possible impurities, crystallinity and crystalline defects, and the textural variations, is taken into account to explain the high differences found in the specific surface area of sepiolites. The studied samples display a high variability in crystallinity, fibre length and texture. The BET surface varies between 77 and 399m2g−1, demonstrating the significant variation in the surface properties in natural sepiolites. Both the external and the microporous area vary between very wide extreme values, from 52m2g−1 to 246m2g−1 for the microporous area and 6m2g−1 to 178m2g−1 for the external area. The exceptionally low values of these properties found in some samples cannot be related to the presence of impurities, but rather to their structural and textural features. Two types of microporosity that can be described are structural microporosity and interfibre microporosity. The SSA and the porosity of each sepiolite is the result of the sum of the intracrystalline or structural microporosity and the textural porosity (interfibre microporosity and mesoporosity). As a consequence, there is a hierarchical distribution of pore sizes, which is different for each sepiolite. The lowest values of microporosity are related to the presence of very open pores and the sepiolites with higher SSA are those having a smaller length and a more closed porosity.
► There is a great variability in the surface properties in natural sepiolites. ► The SSA of sepiolite is not only related to its structural microporosity. ► The texture is a determinative factor influencing the final values of the SSA. ► Two types of microporosity can be describes: structural and interfibre microporosity. ► Pore sizes show a hierarchic distribution that is different for each sample.
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