Determinación de la escala de las firmas de gestión de activos más prominentes mediante el análisis de datos

Peter Phillips y otros autores destacados iluminan la existencia de superpotencias ocultas que ejercen influencia sobre las corporaciones más importantes del mundo, este poder también abarca a importantes entidades de comunicaciones a nivel global. Phillips resalta que 17 de los llamados ‘Gigantes’ gestionan portafolios de inversión con al menos 1 trillón en activos. De la misma manera, existe un grupo pequeño de gestores de activos denominado los ‘Tres Grandes’ (‘Big Three’), gigantes reconocidos a nivel mundial en la gestión de activos que incluyen a BlackRock, Vanguard Group y State Street Corporation. El discurso en torno a estos ‘Gigantes’ y los ‘Tres Grandes’ motivó la aplicación de técnicas de análisis de datos para examinar y validar las afirmaciones realizadas sobre ellos. Los datos, recopilados de diversas fuentes como Yahoo Finance y StockAnalysis.com, fueron sometidos a una limpieza meticulosa para mitigar errores y abordar la falta de información. Posteriormente, tres hipótesis fueron sometidas a una evaluación rigurosa mediante pruebas de hipótesis (hypothesis testing). Como resultado de este proceso, solo una de las tres hipótesis planteadas fue rechazada, lo cual nos llega a concluir que los ’Tres Grandes’ efectivamente poseen una posición muy fuerte en las empresas que pertenecen a los índices más importantes (S&P 500, NASDAQ 100, DJIA) de los mercados financieros norteamericanos.Peter Phillips and other prominent authors shed light on the existence of hidden superpowers that exert influence over the world’s most important corporations. This power also extends to major global communications entities. Phillips highlights that 17 of the so-called ‘Giants’ manage portfolios with a staggering 1 trillion or more in assets. Additionally, there is a small group of institutions called the ‘Big Three,’ globally recognized asset management giants comprising BlackRock, Vanguard Group, and State Street Corporation. The discourse surrounding these ‘Giants’ and the ‘Big Three’ prompted the application of data analytics techniques to scrutinize and validate these assertions. Data, drawn from diverse sources such as Yahoo Finance and StockAnalysis.com, underwent meticulous cleaning to mitigate errors and address missing information. Subsequently, three hypotheses were subjected to rigorous evaluation through hypothesis testing. As a result of this process, only one of the three hypotheses proposed was rejected, leading us to conclude that the ‘Big Three’ indeed hold a very strong position among companies that belong to the most important indices (S&P 500, NASDAQ 100, DJIA) of the American financial markets

Including many-body effects into the Wannier-interpolated quadratic photoresponse tensor

We present a first-principles scheme for incorporating many-body interactions into the unified description of the quadratic optical response to light of noncentrosymmetric crystals. The proposed method is based on time-dependent current-density response theory and includes the electron-hole attraction \textit{via} a tensorial long-range exchange-correlation kernel, which we calculate self-consistently using the bootstrap method. By bridging with the Wannier-interpolation of the independent-particle transition matrix elements, the resulting numerical scheme is very general and allows resolving narrow many-body spectral features at low computational cost. We showcase its potential by inspecting the second-harmonic generation in the benchmark zinc-blende semiconductor GaAs, the layered graphitic semiconductor BC$_{2}$N and the Weyl semimetal TaAs. Our results show that excitonic effects can give rise to large and sharply localized one- and two-photon resonances that are absent in the independent-particle approximation. We find overall good agreement with available experimental measurements, capturing the magnitude and peak-structure of the spectrum as well as the angular dependence at fixed photon energy. The implementation of the method in Wannier-based code packages can serve as a basis for performing accurate theoretical predictions of quadratic optical properties in a vast pool of materials.Comment: 15 pages, 6 figure

Vacatio legis versus retroactividad de las leyes penales favorables: Especial referencia a los delitos fiscal, contable-tributario y contra la Seguridad Social

Con ocasión de la última reforma penal, operada mediante la Ley Orgánica 15/2003, de 25 de noviembre, con entrada en vigor el día 1 de octubre de 2004, el autor analiza los efectos que un amplio período de vacatio legis de las normas penales puede tener sobre el principio constitucional de retroactividad de la norma penal más favorable. Para el autor, un amplio período de vacatio legis en materia penal, establecido sin duda en beneficio de la seguridad jurídica y con el fin de coadyuvar a la publicidad normativa, no puede restringir la aplicación del principio de retroactividad de la ley penal más favorable. Se analiza de forma crítica el estado actual de la jurisprudencia y doctrina sobre el alcance que la vacatio legis tiene sobre las conductas que son totalmente despenalizadas y sobre las conductas que son parcialmente despenalizadas (a través de la elevación de los límites cuantitativos de la punibilidad). Asimismo, el autor considera que el principio de retroactividad de la ley penal más favorable está incluido en el principio de legalidad penal, consagrado como derecho fundamental en el artículo 25.1 de la Constitución Española y, por tanto, goza de las máximas garantías que la Constitución ofrece a los derechos fundamentales. Esta interpretación la fundamenta en el criterio hermenéutico establecido en el artículo 10.2 de la Constitución respecto a la interpretación de los derechos fundamentales y las libertades que la Constitución reconoce, aplicándose, por tanto, el artículo 15.1 del Pacto Internacional de Derechos Civiles y Políticos suscrito por España. El estudio se realiza con especial referencia a los delitos fiscal, contable-tributario y contra la Seguridad Social

Control de la madurez en frutos por medio de ensayos de impacto.

En anteriores trabajos se ha observado que la respuesta de los frutos a un impacto mecánico está muy influida por su estado de madurez. Se realizaron ensayos de impacto sobre peras cv. Limonera, a lo largo de 12 semanas de conservación frigorífica y de maduración controlada. El impacto desde 4 cm de altura (equivalente a 0,02 J) resulta no destructivo y puede utilizarse para la determinación del estado de madurez de estos frutos. Por métodos de regresión lineal múltiple sobre los 15 para metros del impacto más representativos se obtienen buenas p r e dicciones de la madurez, representada por la fuerza de corte de probetas de pulpa, FC (N)

UV dosage unveils toxic properties of weathered commercial bioplastic bags

Previous studies indicated that weathered conventional plastics and bioplastics pose ecotoxicological risks. Here, the effects of artificial and natural weathering on the ecotoxicity of three compostable bags and a conventional polyethylene (PE) bag are investigated. With that aim, a 21-day artificial indoor weathering experiment featuring UV light, UV-filtered light, and darkness was run simultaneously to a 120-day outdoor littoral mesocosm exposure featuring natural light, UV-filtered light, and shaded conditions. Acute toxicity of so-weathered plastic specimens was tested in vivo using the sensitive Paracentrotus lividus sea-urchin embryo test. PE was nontoxic from the beginning and did not gain toxicity due to UV weathering. In contrast, for bioplastics, dry artificial UV weathering increased toxicity in comparison to the dark control. Weathering in outdoor mesocosm led to a rapid loss of toxic properties due to leaching in rainwater. With a higher UV dosage, a plastic-type-dependent regain of toxicity was observed, most likely driven by enhanced availability or transformation of functional additives or due to bioplastic degradation products. PE showed moderate UV absorbance, while bioplastics showed high UV absorbance. This study highlights the potential of biodegradable plastics to pose enhanced ecotoxicological risk due to weathering under environmentally relevant conditions.Agencia Estatal de Investigación | Ref. PCI2020-112110Agencia Estatal de Investigación | Ref. FPU19/02280Universidade de Vigo/CISU

Mesocosm trials reveal the potential toxic risk of degrading bioplastics to marine life

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGIf biodegradable plastics tackle the marine plastic pollution problem sufficiently remains questionable. To gain more insight in degradability, performance, and the impact of degradation on the toxicity, commercial bags made from two biodegradable plastics and one conventional plastic (PE) were exposed for 120 days in a mesocosm featuring benthic, pelagic, and littoral habitat simulations. Degradability was assessed as weight loss, and specimens were tested for toxicity using Paracentrotus lividus sea-urchin larvae after different exposure times. Both biodegradable bags showed degradation within 120 days, with the littoral simulation showing the highest and the pelagic simulation the lowest decay. Disregarding habitat, the home-compostable plastic showed higher marine degradation than the industrial-compostable material. The relevant initial toxicity of both biopolymers was lost within 7 days of exposure, pointing towards easily leachable chemical additives as its cause. Interestingly, littoral exposed specimens gained toxicity after 120 days, suggesting UV- induced modifications that increase biopolymer toxicity.Agencia Estatal de Investigación | Ref. PCI2020-112110Ministerio de Universidades | Ref. FPU19/0228

Quantification of soluble fibre in feedstuffs for rabbits and evaluation of the interference between the determinations of soluble fibre and intestinal mucin.

This work compared the quantification of soluble fibre in feeds using different chemical and in vitro approaches, and studied the potential interference between soluble fibre and mucin determinations. Six ingredients: sugar beet pulp (SBP), SBP pectins, insoluble SBP, wheat straw, sunflower hulls and lignocellulose, and seven rabbit diets, differing in soluble fibre content, were evaluated. In experiment 1, ingredients and diets were analyzed for total dietary fibre (TDF), insoluble dietary fibre (IDF), soluble dietary fibre (SDF), aNDFom (corrected for protein, aNDFom-cp) and 2-step pepsin/pancreatin in vitro DM indigestibility (corrected for ash and protein, ivDMi2). Soluble fibre was estimated by difference using three procedures: TDF?IDF (SDFIDF), TDF?ivDMi2 (SDFivDMi2), and TDF?aNDFom-cp (SDFaNDFom-cp). Soluble fibre determined directly (SDF) or by difference as SDFivDMi2 were not different (109 g/kg DM, on average). However, when it was calculated as SDFaNDFom-cp the value was 40% higher (153 g/kg DM, P menor que 0.05), whereas SDFIDF (124 g/kg DM) did not differ from any of the other methods. The correlation between the four methods was high (r ? 0.96; P ? 0.001; n = 13), but it decreased or even disappeared when SBP pectins and SBP were excluded and a lower and more narrow range of variation of soluble fibre was used. In experiment 2, the ivDMi2 using crucibles (reference method) were compared to those made using individual or collective ankom bags in order to simplify the determination of SDFivDMi2. The ivDMi2 was not different when using crucibles or individual or collective ankom bags. In experiment 3, the potential interference between soluble fibre and intestinal mucin determinations was studied using rabbit intestinal raw mucus, digesta and SBP pectins, lignocelluloses and a rabbit diet. An interference was observed between the determinations of soluble fibre and crude mucin, as contents of TDF and apparent crude mucin were high in SBP pectins (994 and 709 g/kg DM) and rabbit intestinal raw mucus (571 and 739 g/kg DM). After a pectinase treatment, the coefficient of apparent mucin recovery of SBP pectins was close to zero, whereas that of rabbit mucus was not modified. An estimation of the crude mucin carbohydrates retained in digesta TDF is proposed to correct TDF and soluble fibre digestibility. In conclusion, the values of soluble fibre depend on the methodology used. The contamination of crude mucin with soluble fibre is avoided using pectinase

Carbon storage and stability of soil organic matter in a coffee agroecosystem in Sierra Sur de Oaxaca, Mexico

We evaluated the ability of the soils in a shade coffee agroecosystem under different handling conditions to accumulate stable forms of carbon in the Sierra Sur of Oaxaca, for this we quantify the soil carbon store and performed the isolation and chemical characterization of soil organic matter by chemical fractionation, UVvisible and infrared spectroscopy in the first 40 cm depth. Results showed no significant differences in carbon stores between handling conditions, reaching mean values 150 Mg C ha-1 . Humification patterns are consistent for all soils and indicate that over 50% of soil organic matter found in the insolubilization humins and between 15 and 20% are humic acids. This fraction, presumably the most stable, is made up of molecules whose aromatic and maturation has a positive relationship with increasing altitude and clay content. According to the above confirms the ability of shade-coffee agroecosystems to accumulate high carbon content associated with stable forms of soil mineral fraction.Se evaluó la capacidad de los suelos de un agroecosistema cafetalero de sombra bajo diferentes condiciones de manejo para acumular formas estables de carbono, en la Sierra Sur de Oaxaca; para ello, se cuantificó el almacén de carbono edáfico y se realizó el aislamiento y caracterización química de la materia orgánica del suelo mediante fraccionamiento químico, espectroscopía UV-visible e infrarroja en los primeros 40 cm de profundidad. Los resultaron no mostraron diferencias significativas para los almacenes de carbono entre condiciones de manejo, situándose en valores promedio de 150 Mg C ha-1. Los patrones de humificación son consistentes para todos los suelos e indican que más del 50 % de la materia orgánica del suelo se encuentra en las huminas de insolubilización y entre el 15 y 20 % corresponde a los ácidos húmicos. Esta fracción, presumiblemente la más estable, está conformada por moléculas cuya aromaticidad y maduración tiene una relación positiva con el incremento de altitud y el contenido de arcillas en el suelo. De acuerdo a lo anterior se corrobora la capacidad de los agroecosistemas cafetaleros bajo sombra para acumular elevados contenidos de carbono en formas estables asociadas con la fracción mineral del suelo.Consejo Nacional de Ciencia y Tecnología Posgrado en Ciencias Biológicas, UNA

Understanding the large shift photocurrent of WS2_{2} nanotubes: A comparative analysis with monolayers

We study the similarities and differences in the shift photocurrent contribution to the bulk photovoltaic effect between transition-metal dichalcogenide monolayers and nanotubes. Our analysis is based on density functional theory in combination with the Wannier interpolation technique for the calculation of the shift photoconductivity tensor. Our results show that for nanotube radii of practical interest $r>60$~\AA, the shift photoconductivity of a single-wall nanotube is well described by that of the monolayer. Additionally, we quantify the shift photocurrent generated under realistic experimental conditions like device geometry and absorption capabilities. We show that a typical nanotube can generate a photocurrent of around 10 nA, while the monolayer only attains a maximum of 1 nA. This enhancement is mainly due to the larger conducting cross section of a nanotube in comparison to a monolayer. Finally, we discuss our results in the context of recent experimental measurements on WS$_{2}$ monolayer and nanotubes[Zhang et al., Nature 570, 349 (2019)].Comment: 11 pages, 9 figure

In situ test: cotton sheets against mosquito bites in India

[EN] Historically, fabrics were considered as a source of warmth and protection against weather conditions. Nowadays, fabrics can be converted into smart textiles and through this process new properties are conferred to them. For that purpose, microcapsules can play an important role in that they can be used within many application areas including medicine or pharmaceuticals. Malaria, dengue fever and other diseases are typically spread through mosquito bites. This is a concern of many authorities in affected countries and significant research is being conducted today in order to reduce incidence. The aim of the study reported here is not only to demonstrate the effectiveness of microcapsules on cotton fabrics as a prevention to mosquito bites but also to test this in situ. Different fabrics were prepared and tested in two Indian regions. Laboratory tests were performed according to a standard designed by the Swiss Tropical laboratory. 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