707 research outputs found

    Nonassociative real H*-algebras

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    We prove that, if A denotes a topologically simple real (non-associative) H*-algebra, then either A is a topologically simple complex H*-algebra regarded as real H*-algebra or there is a topologically simple complex H*-algebra B with *-involution r such that A = {b € B : r(b) = b*} . Using this, we obtain our main result, namely: (algebraically) isomorphic topologically simple real H*-algebras are actually * isometrically isomorphic

    Sectores productivos y espacios de conflicto: pesca y petróleo en la sonda de Campeche

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    Objetivo y planteamiento del problema: La Sonda de Campeche es una zona marítima del Golfo de México en donde por más de 60 años se ha realizado la explotación de dos importantes recursos naturales para la economía nacional y regional de esta región: las pesquerías del camarón y la extracción de petróleo. Ambas actividades, aunque comparten el mismo espacio, son completamente diferentes en cuanto a la extracción de sus respectivos productos. Esencialmente, la actividad pesquera del camarón está sujeta a varios condicionamientos para su desarrollo: primero, de carácter físico-biológico y territorial; segundo, a las relaciones comerciales de carácter internacional, nacional y local; tercero, a las normatividades y reglamentaciones de carácter gubernamental y de observancia pública por parte del sector involucrado en la actividad. En tanto que la actividad petrolera está sujeta a otros condicionamientos: primero, existe una demanda del mercado nacional e internacional; segundo, es un energético de la cual depende la industria y la economía de los países industrializados y no industrializados. El objetivo del trabajo es presentar un panorama de ambas actividades productivas en un mismo espacio marítimo territorial, hoy día en conflicto por la intervención de diversos actores sociales y agentes económicos que dan pie a la reconfiguración del territorio. Esto se hace mediante la identificación de diversas escalas de análisis espacial por etapas. Conclusiones: Se señalan los intereses de los actores en espacios de conflictos, lo cual impide el desarrollo articulador de ambos sectores productivos importantes para la región y para los intereses geoestratégicos nacionales e internacionales

    Performance of Slow-Growing Chickens Fed with Tenebrio molitor Larval Meal as a Full Replacement for Soybean Meal

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    Insect larval meal is an increasingly common protein source in poultry systems. In this study, the effect of replacing soybean meal with Tenebrio molitor larval meal on the performance of slow-growing chickens was assessed. A total of 128 one-day-old chickens (Colorield) were randomly divided into a control group (C) (n = 64), fed with soybean meal, and an experimental group (TM) (n = 64), fed with T. molitor larvae meal. The chicks were slaughtered after 95 days. Three different isoenergetic and isoproteic diets (F1, F2 and F3) were used for each group. The F1 diet resulted in higher body weight gain and higher feed and water intakes in group C, but a lower feed conversion ratio. Contrarily, diets F2 and F3 did not produce differences in the studied parameters between the two groups, except for body weight gain in the case of diet F2, which was highest in group C. Therefore, weight gain and feed and water intakes were significantly higher in group C, but there were no differences in feed conversion ratio or live weight. In conclusion, the total replacement of soybean meal with T. molitor larvae meal resulted in a reduction in feed intake and a consequent reduction in weight. During this period, partial rather than total substitution may be recommended. © 2022 by the authors. Licensee MDPI, Basel, Switzerland

    Spin orbit in curved graphene ribbons

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    We study the electronic properties of electrons in flat and curved zigzag graphene ribbons using a tight-binding model within the Slater Koster approximation. We find that curvature dramatically enhances the action of spin orbit effects in graphene ribbons and has a strong effect on the spin orientation of the edge states: whereas spins are normal to the surface in the case of flat ribbons, this is no longer the case in the case of curved ribbons. We find that for the edge states, the spin density lies always in the plane perpendicular to the ribbon axis, and deviate strongly from the normal to the ribbon, even for very small curvature and the small spin orbit coupling of carbon. We find that curvature results also in an effective second neighbor hopping that modifies the electronic properties of zigzag graphene ribbons. We discuss the implications of our finding in the spin Hall phase of curved graphene Ribbons.Comment: 9 pages, 9 figure

    Influence of cold pre-fermentation maceration on the volatilomic pattern and aroma of white wines

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    Aroma compounds play a key role in wine quality due to their importance in wine aroma. The aim of the present study is to investigate the influence of cold pre-fermentative maceration (CPM) treatment on aromatic and sensory properties of white wines from four grape varieties (Tempranillo Blanco, Maturana Blanca, Viura and Garnacha Blanca) during two consecutive years (2019 and 2020). A total of 62 aroma compounds belonging to different chemical families were identified using headspace solid-phase microextraction combined with gas chromatography mass spectrometry (HS-SPME/GC-MS). CPM treatment enhanced the total relative concentration of alcohols, esters and acids compared to control wines. Regarding sensorial properties, esters made the greatest contribution to the studied white wines, mainly through the development of floral and fruity notes. On the other hand, CPM treatment did not significantly influence the total relative concentration of terpenoids, and different trends were observed according to grape variety and vintage. The obtained results showed differences in the wine’s aromatic complexity according to the grape variety, the vintage and the treatment applied and suggested that CPM treatment could represent a suitable approach to manipulate the aromatic profile and enhance the aromatic quality and complexity of wine.info:eu-repo/semantics/publishedVersio

    GPS, LiDAR and VNIR data to monitor the spatial behavior of grazing sheep

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    Traditional knowledge about the behavior of grazing livestock is about to disappear. Shepherds well know that sheep behavior follows non-random patterns. As a novel alternative to seeking behavioral patterns, this study quantified the grazing activities of two sheep flocks of Churra breed (both in the same area but separated by 10 years) based on Global Position System (GPS) monitoring and remote monitoring sensing techniques. In the first monitoring period (2009-10), geolocations were recorded every 5 min (4, 240 records), while in the second one (2018-20), records were taken every 30 min (7, 636 records). The data were clustered based on the day/night and the activity (resting, moving, or grazing). An airborne LiDAR dataset was used to study the slope, aspect, and vegetation height. Four visible-infrared orthophotographs were mosaicked and classified to obtain the land use/land cover (LU/LC) map. Then, GPS locations were overlain on the terrain features, and a Chi-square test evaluated the relationships between locations and terrain features. Three spatial statistics (directional distribution, Kernel density, and Hot Spot analysis) were also calculated. Results in both monitoring periods suggested that the spatial distribution of free-grazing ewes was non-random. The flocks showed strong preferences for grazing areas with gentle north-facing slopes, where the herbaceous layer formed by pasture predominates. The geostatistical analyses of the sheep locations corroborated those preferences. Geotechnologies have emerged as a potent tool to demonstrate the influence of environmental and terrain attributes on the non-random spatial behavior of grazing sheep. © 2022 Malque Publishing. All rights reserved

    On the application of extended reality technologies for the evaluation of product characteristics during the initial stages of the product development process

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    [EN] Fast-growing global markets are forcing companies to continuously re-assess customer needs when designing new products. Product evaluation is a critical task to ensure success, but it can require significant financial and time investments. From an end-user standpoint, consumers must also evaluate multiple design options before purchasing a product, which is often a complex process, especially in online environments where traditional formats coexist with more sophisticated media. Modern extended reality technologies have become an effective tool for product assessment in professional design environments as well as a powerful mechanism for consumers during decision making activities. However, the modality used to view and evaluate the product may affect the perceptual response and thus the user¿s overall evaluation. In this paper, we examine the influence of visual media in product assessment using different designs of a particular product typology. We discuss two studies where a group of participants used the semantic differential technique to evaluate four chair designs displayed in three different media. In our first study, participants used simultaneous evaluation to assess the products as presented in photographs, a non-immersive environment, and an Augmented Reality (AR) experience. In the second study, participants evaluated the product separately as viewed in non-photorealistic rendering, AR, and virtual reality (VR). We used the ¿Aligned Rank Transform¿ proceedings to find differences between groups for the semantic scales, the overall evaluation, the purchasing decision, and the response confidence. Our results show that visual media influences product perception. Certain characteristics in Jordan's physio-pleasure category are particularly significant as perceptual differences are more pronounced. Immersive media can highlight some product attributes and a joint evaluation can help minimize these differences.The authors would like to thank the team at Clon Digital for providing us with a software license to perform the experiment, and students Jenny Trieu, Abizer Raja, Arturo Barrera, and Carrah Kaijser from the University of Houston for the inspiration for the chair designs used in our study.Palacios-Ibáñez, A.; Navarro-Martínez, R.; Blasco-Esteban, J.; Contero, M.; Dorribo-Camba, J. (2023). On the application of extended reality technologies for the evaluation of product characteristics during the initial stages of the product development process. Computers in Industry. 144. https://doi.org/10.1016/j.compind.2022.10378014

    New route to pyrido[1,2-b]pyridazinium inner salts. Evidence of a 1,3-dipolar cycloaddition-ring expansion process

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    2-Alkoxycarbonylpyridinium N-aminides behave as 1,3-dipoles when reacted with Michael accepters, giving rise to the corresponding cycloadducts which, depending on their regioisomeric nature, subsequently undergo a ring expansion to give pyrido[1,2-b]pyridazinium inner salts.We wish to express our thanks to the Comisión Interministerial de Ciencia y Tecnología (CICYT, project PM97-004) and to the Ministerio de Educación y Ciencia for a grant to one of us (J.V.M)

    Effect of Melatonin as an Antioxidant Drug to Reverse Hepatic Steatosis: Experimental Model

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    Introduction. The hepatic steatosis of the nonalcoholic origin or NAFLD is increasing at present, particularly in Western countries, parallel to the increase in obesity, constituting one of the most prevalent hepatic processes in the Western society. Melatonin has been successfully tested in experimental models in mice as a drug capable of reversing steatosis. The effect of melatonin on fat metabolism can be summarized as a decrease in lipid peroxidation and a decrease in oxidative stress, biochemical phenomena intimately related to fat deposition in the hepatocyte. There are hardly any studies in large animals. Objective. In this study, we investigate the effects of melatonin administered orally at a dose of 10 mg/kg/day to reverse established hepatic steatosis induced by a special diet in a porcine animal model. Materials and Methods. We analyze the parameters of oxidative stress: malondialdehyde (MDA), 4-hydroxyalkenals (4-HDA), and carbonyls, degree of fat infiltration (analyzed by direct vision by a pathologist and by means of a computer program of image treatment), and serological parameters of lipid metabolism and hepatic damage. These parameters were analyzed in animals to which hepatic steatosis was induced by means of dietary modifications. Results. We have not been able to demonstrate globally a beneficial effect of melatonin in the improvement or reversal of liver steatosis once established, induced by diet in a porcine animal model. However, we have found several signs of improvement at the histological level, at the level of lipid metabolism, and at the level of oxidative stress parameters. We have verified in our study that, in the histological analysis of the liver sample by means of the program image treatment (free of subjectivity) of the animals that continue with the diet, those that consume melatonin do not increase steatosis as much as those that do not consume it significantly (p=0.002). Regarding the parameters of oxidative stress, MDA modifies in a significant manner within the group of animals that continue with the diet and take melatonin (p=0.004). As for lipid metabolism, animals that maintain the steatotic diet and take melatonin lower total and LDL cholesterol levels and increase HDL levels, although these results do not acquire statistical significance. Conclusions. In this study, it has not been possible to demonstrate a beneficial effect of melatonin in the improvement or reversal of liver steatosis once established and induced by diet in the porcine model. It is true that signs of improvement have been found at the histological level, at the level of lipid metabolism, and at the level of oxidative stress phenomena, when comparing animals with established steatosis that are treated with melatonin with those who do not take it. This work is the first study conducted in a large animal model in which the effect of melatonin is studied as a treatment in the reversal of established hepatic steatosis
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