On the commutator length of compact Lie groups

In this short note we show that the path-connected component of the identity of the derived subgroup of a compact Lie group consists just of commutators. We also discuss an application of our main result to the homotopy type of the classifying space for commutativity for a compact Lie group whose path-connected component of the identity is abelian.Comment: 6 pages, comments welcome

Sobre la clasificación de espacios topológicos finitos

El estudio de los espacios topológicos finitos cobra popularidad en 1937 con un artículo de Alexandroff [1] en el cual describe la estrecha relación que tienen con los conjuntos finitos preordenados. Sin embargo, hasta el año 1966 surgen dos nuevos artículos de gran importancia sobre el tema. Uno de estos es debido a Stong [16], en el cual exhibe una clasificación por tipo de homotopía; además extiende el trabajo de Alexandroff con un estudio más detallado de la correspondencia entre espacios finitos y preórdenes antes mencionada. El segundo artículo es debido a McCord [9], este trabajo tiene un enfoque totalmente distinto al de Stong; presentando la relación que existe entre los espacios finitos y los poliedros compactos

On the cohomological triviality of the center of the Frattini subgroup

We improve the existing lower bounds on the order of counterexamples to a conjecture by P. Schmid, determine some properties of the possible counterexamples of minimum order for each prime, and the isomorphism type of the center of the Frattini subgroup for the counterexamples of order 256. We also show that nonabelian metacyclic p-groups, nonabelian groups of maximal nilpotency class and 2-groups of coclass two satisfy the conjecture.Comment: 13 pages, comments are welcom

Blockchain in the Food Industry: Integrating Machine Learning in a Systematic Literature Review

This study provides a systematic literature review of blockchain technology in the food industry with a supply chain lens. We identify primary and sub-themes, discuss implications and applications in terms of delivering value and propose literature-informed future research directions. This review uncovered three primary themes: a) Value Creation; b) Supply Chain Digitization; and c) Transformation. It demonstrates that digitalizing food networks with blockchain technology may benefit from increased stakeholder involvement and data visibility to gain competitive advantage. Beyond the theoretical contributions, this research provides a methodological contribution by demonstrating the uses of machine learning techniques to perform systematic literature reviews

Numerical Evaluation in a Scaled Rotor-Less Nozzle Vaned Radial Turbine Model under Variable Geometry Conditions

[EN] The widespread trend of pursuing higher efficiencies in radial turbochargers led to the prompting of this work. A 3D-printed model of the static parts of a radial variable geometry turbine, the vaned nozzle, and the volute, was developed. This model was up-scaled from the actual reference turbine to place sensors and characterize the flow around the nozzle vanes, including the tip gap. In this study, a computational model of the scaled-up turbine was carried out to verify the results in two ways. For this model, firstly compared with an already validated CFD turbine model of the real device (which includes a rotor), its operating range was extended to different nozzle positions, and we checked the issues with rotor-stator interactions as well as the influence of elements such as the screws of the turbine stator. After showing results for different nozzle openings, another purpose of the study was to check the effect of varying the clearance over the tip of the stator vanes on the tip leakage flow since the 3D-printed model has variable gap height configurations.This research work was supported by Grant PDC2021-120821-I00, funded by MCIN/AEI/10.13039/501100011033 and by European Union NextGeneration EI/PRTR.Serrano, J.; Tiseira, A.; López-Carrillo, JA.; Hervás-Gómez, N. (2022). Numerical Evaluation in a Scaled Rotor-Less Nozzle Vaned Radial Turbine Model under Variable Geometry Conditions. Applied Sciences. 12(14):1-17. https://doi.org/10.3390/app12147254117121

La enseñanza de la filosofía desde nuestra realidad latinoamericana: El caso de la Universidad Nacional de Costa Rica

Para iniciar este ensayo, acudimos a la vieja pregunta ¿hay filosofía en América Latina? Según Estermann, el saber de los pueblos indígenas es sin duda filosofía, al menos en un sentido amplio, ello si se concibe a la filosofía latinoamericana como “el esfuerzo humano para entender el mundo” (2009, p. 22), mediante la especulación cosmogónica y el cuestionamiento o si se le ve como un proceso de estetización gnoseológico, metafísico, ético y político (por supuesto, estos términos hay que relativizarlos al referirnos al mundo indígena), que tiene al mito como punto de partida y a la cosmogonía como unidad compleja que condensa los vínculos míticos (Cassirer, 2012)

El tratamiento legal de la violencia del narcotráfico, como actos terroristas y su vinculación con la delincuencia organizada.

Este artículo busca analizar los vínculosentre terrorismo, narcotráfico ydelincuencia organizada transnacional,mediante el uso de una metodologíadeductiva y analítica. Se analizan enprimer término, los antecedentes normativosdel terrorismo, el narcotráfico y ladelincuencia organizada transnacional,para de ahí explorar las deficiencias delos sistemas institucionales nacionales,problemas como la corrupción y laeconomía informal, que son consideradoscomo factores decisivos en estaproblemática. Así mismo, se examinael enfoque de lucha contra el terrorismoy su influencia en América Latina parala militarización de la lucha contra elnarcotráfico. Finalmente, se explora elpapel que la Declaración de Seguridad delas Américas de la ORGANIZACIÓN DEESTADOS AMERICANOS y su conceptode “seguridad humana” hemisférica, yel efecto que la Convención de Palermosobre Delincuencia Organizada Transnacional,han jugado a la hora de abordarel tratamiento de la inseguridad a nivelregional en Latinoamérica.This article seeks to analyze the links between terrorism, drug trafficking and transnational organized crime, through the use of a deductive and analytical methodology. First, the normative background of terrorism, drug trafficking and transnational organized crime are explored, in order to show the weaknesses of national institutional systems, problems such as corruption and the informal economy, which are considered as decisive factors in this problem. Likewise, it examines the approach to fight against terrorism and its influence in Latin America for the militarization of the fight against drug trafficking. Finally, it explores the role that the Declaration of Security of the Americas of the Organization of American States and its concept of “human security” in the hemisphere, and the effect that the Palermo Convention on Transnational Organized Crime has played in addressing The treatment of insecurity at the regional level in Latin America

Valorization of chloromethanes by hydrodechlorination with metallic catalysts

The performance of Pd, Pt, Rh and Ru based catalysts in the hydrodechlorination of chloromethanes to obtain ethane and ethylene was evaluated by means of computational analysis and hydrodechlorination experiments. A computational analysis using density functional theory (DFT) was developed to obtain preliminary insight on the potential catalytic mechanisms for the reactions involved using palladium, platinum, rhodium and ruthenium metallic clusters. Stable catalytic intermediates were obtained by quantum-chemical calculations in the hydrodechlorination of dichloromethane on Pd6and Rh6clusters, presenting [rad][rad]CH2and [rad]CH3radicals and C2H4, C2H6and CH4products. On the contrary, it was not possible to obtain all these stable intermediates using Pt6and Ru6clusters. Theoretical analysis revealed lower desorption energies for ethane and ethylene products in Pd6than in Rh6clusters, what indicates a favorable selectivity of Pd-based catalyst for desired C2products. Then, carbon supported catalysts containing these four metals were prepared and experimentally evaluated in the hydrodechlorination of dichloromethane (DCM) and trichloromethane (TCM) at low H2excess and a reaction temperature range of 150-400 °C. In agreement with computational results, in experimental tests, the Pd based catalyst showed the best performance for the hydrodechlorination of chloromethanes to obtain C2products, followed by Rh, Ru and Pt have a poor performance, in special Pt based catalyst, which shows almost no selectivity to C2products. This computational and experimental study emphasizes, for the first time, the good performance (high activity and selectivity) of Pd carbon supported catalysts in the valorization of chloromethane compounds to obtain C2hydrocarbon productsThe authors gratefully acknowledge financial support from the Spanish Ministerio de Economía y Competitividad (MINECO) through the project CTM 2014-53008 and to the “Centro de Computación Científica de la Universidad Autónoma de Madrid” for computational facilitie

Comparison of Different Techniques for the Determination of Platinized Cytostatic Drugs in Urine Samples

Platinum-based cytostatic drugs are one of the most widely used cancer treatments. They are excreted via the urinary tract and can reach the environment through wastewater, posing a risk to human health due to their side effects. Four identification and quantification techniques, including liquid chromatography (LC) separation coupled to (i) a diode array ultraviolet (UV(DAD)) (ii), mass spectrometer in single ion monitoring mode (LC-MS) and (iii) multiple reaction monitoring mode (LC-MS/MS) and (iv) derivatization with diethyldithiocarbamate prior to LC-MS/MS analysis, have been optimized and compared for the multiresidue determination of main platinized cytostatic drugs (cisplatin, carboplatin, and oxaliplatin) in urine samples. Parameters that affect the efficiency of the chromatographic separation and analytical determination of different methods (column, mobile phase, wavelength, precursor ions, fragmentor, and product ions) were optimized. Analytical features, such as matrix effect, sensitivity, precision, selectivity, and linearity, were calculated. In terms of selectivity, the derivatization technique was discarded since it was only applicable to the platinated sum. A high dilution of the sample with LC-UV(DAD) was needed to reduce the matrix effect. Overall, the LC-MS/MS method presented the best analytical features (% RSD ≤ 12.8%, R2 ≥ 0.991, or method-detection limits between 0.01–1 µg mL−1). The selected method was applied to the quantification of platinized cytostatic drugs in hospital urine samples from oncologic patients.Ministerio de Industria, Comercio y Turismo AEI-010500-2021-79, AEI-010500-2021B-9