504 research outputs found
Bancos de tempo e creación de capital social: unha análise de datos de transaccións
This article uses transaction data from three time banks located in Barcelona to analyze their otential to generate bonding and bridging social capital for their members. Regarding bonding social capital, the findings are in line with the related literature in terms of the average number of trading partners and the ego-network density. However, reciprocity is a more frequent form of behavior in our data than in other time banks from other countries. Concerning bridging social capital and considering different age groups, the results show slight evidence of homophilic behavior, although intergenerational transactions are also present, being more frequent between more similar age groups. Finally, we explore the influence of age on the time it takes for members to engage in transactions, which could somehow be related to their potential motivations behind joining a time bank.Este artigo utiliza datos de transaccións de tres bancos do tempo situados en Barcelona para analizar o seu potencial para xerar capital social entre os seus membros. En canto aos vínculos do capital social, os resultados están en consonancia coa literatura relacionada en canto ao número medio de socios de intercambio e a densidade da ego-network. Non obstante, a reciprocidade é máis frecuente nos nosos datos que noutros bancos doutros países. En canto á xeración do capital social entre diferentes grupos de individuos e considerando a idade, os resultados mostran lixeiras evidencias de comportamento homofílico, aínda que tamén están presentes transaccións interxeracionais, sendo máis frecuentes entre grupos de idade máis próximos. Finalmente, exploramos a influencia da idade no tempo que tardan os membros en realizar transaccións, o que podería estar relacionado coas súas posibles motivacións detrás de unirse a un banco de tempo.Authors acknowledge financial support from Ministry of Science and Innovation, Grants PID2021-124860NB-I00 (Ángeles Carnero), Grants PID2022-139458NB-I00 and PID2022-138706NB-I00 (Blanca Martinez), Grant PID2022-139614NB-C21 (Rocío Sánchez Mangas); and from Generalitat Valenciana, Grant CIPROM/2021/060 (Ángeles Carnero)
Precision Nutrition and Metabolic Syndrome Management
Precision nutrition is an emerging concept encompassing an integrated action considering not only the genetic/epigenetic makeup and ethnic aspects of individuals, but other personalized phenotypical features, such as family and individual clinical issues, previous diseases and therapeutic treatments, perinatal nutrition, food likes/dislikes, allergies/intolerances, lifestyle attitudes and patterns, social and cultural circumstances or religious beliefs, etc. In this context, chronic disease prevalence is a global public health problem itself, which is also accompanied by a number of complications, including insulin resistance, hypertension, hypercholesterolemia, fatty liver, inflammation, oxidative status and immunocompetence disturbances, and other adverse manifestations related to metabolic syndrome, which may need individualized nutritional approaches. Therefore, the current Special Issue attempts to provide specific nutritional strategies to prevent or treat the complications associated with metabolic syndrome features concerning diabetes, vascular events, liver diseases, dyslipemia, and cancer with a precision nutrition scope
Reinstatement of Squilla Steinh., a priority name against the illegitimate Charybdis Speta (Hyacinthaceae, Urgineoideae)
Squilla Steinh. was considered to be an orthographic variant of Scilla L., and therefore the new genus Charybdis Speta was created to include Scilla maritima L. and related taxa occurring in the Mediterranean. Molecular phylogenetic studies recovered Charybdis as distant from Urginea; this finding was also supported by morphology and phytochemistry data. However, after typification of Scilla using S. maritima by Rafinesque, Charybdis became illegitimate under Art. 52 of the Shenzhen Code as its name became superfluous when published. A binding decision was requested from the Nomenclature Committee for Vascular Plants (NCVP) on whether Scilla L. and Squilla Steinh. are sufficiently alike to be considered orthographic variants and, hence, to be confused. Most members of the committee favour treating Squilla as not confusable with Scilla, which leaves the former name available for the current concept of Charybdis. In this context, we reevaluate the taxonomy of the genus, accepting 12 species of which eight are accommodated in Squilla as new combinations. Conversely, one of the species of Charybdis is transferred here to Urginavia. Nomenclatural types (including designation of 13 lectotypes, one neotype and one epitype) and the most relevant synonyms are given for each accepted taxon. An identification key is also presented for Squilla to assist future taxonomic studies in this group. We also include a revision of the taxonomic circumscription of the taxa related to S. undulata.This work was partly supported by the grants ACIE18-03, UAUSTI18-02 and UAUSTI19-08 from the University of Alicante
Mobbing and workers' health: an empirical analysis for Spain
his paper analyzes empirically the impact of mobbing on the health of workers in Spain. Based on the Sixth Spanish Survey on Working Conditions, we first describe the differences in health among mobbed and not mobbed workers, sing two different indicators: the worker's self-perception that work affects health and the presence of bad health symptoms. The descriptive evidence shows that mobbing victims perform worse on such health indicators. We estimate the effect of being mobbed on the probability of suffering from health problems, taking into account the potential endogeneity of mobbing. Our estimates show that being a mobbing victim increases significantly the probability of having bad health, independently on the indicator used. Moreover, when bad health is measured by the perception indicator, we find that the effect of mobbing is underestimated if endogeneity is not accounted for.bullying at workplace, moral harassment
Chemical Activation of Lignocellulosic Precursors and Residues: What Else to Consider?
This paper provides the basis for understanding the preparation and properties of an old, but advanced material: activated carbon. The activated carbons discussed herein are obtained from “green” precursors: biomass residues. Accordingly, the present study starts analyzing the components of biomass residues, such as cellulose, hemicellulose, and lignin, and the features that make them suitable raw materials for preparing activated carbons. The physicochemical transformations of these components during their heat treatment that lead to the development of a carbonized material, a biochar, are also considered. The influence of the chemical activation experimental conditions on the yield and porosity development of the final activated carbons are revised as well, and compared with those for physical activation, highlighting the physicochemical interactions between the activating agents and the lignocellulosic components. This review incorporates a comprehensive discussion about the surface chemistry that can be developed as a result of chemical activation and compiles some results related to the mechanical properties and conformation of activated carbons, scarcely analyzed in most published papers. Finally, economic, and environmental issues involved in the large-scale preparation of activated carbons by chemical activation of lignocellulosic precursors are commented on as well.This research was funded by Generalitat Valenciana (PROMETEO/2018/076), European Commission/FEDER, and the University of Alicante (VIGROB-136)
Ru Catalysts Supported on Commercial and Biomass-Derived Activated Carbons for the Transformation of Levulinic Acid into γ-Valerolactone under Mild Conditions
Ru catalysts (1 wt.%) supported on commercial and biomass-derived activated carbons (AC) have been prepared, thoroughly characterized, and used in the hydrogenation of levulinic acid to produce gamma-valerolactone (GVL). This is an important platform compound that plays a key role in the production of liquid fuels and that can also be used, for example, as a food flavoring agent, antifreeze, and solvent. The study focuses on the influence of the carbon support characteristics, such as porous texture and acidity, on the properties and performance (LA conversion and selectivity to GVL) of the catalysts. Catalytic activity tests have been carried out at 170 °C and also in noticeably milder conditions (70 °C) to implement a less energy-demanding process. All the catalysts show high LA conversion and GVL yield at 170 °C, while at 70 °C, important differences between them, related to the support properties, have been found. The catalysts prepared with more acidic supports show better catalytic properties: very good catalytic performance (98% LA conversion and 77% selectivity to GVL) has been obtained in mild temperature conditions.This research was funded by the Spanish Ministry of Science, Innovation and Universities (RTI2018-095291-B-I00), Generalitat Valenciana (PROMETEO/2018/076), European ComissionFEDER, and the University of Alicante (VIGROB-136)
H2 production by cellulose photoreforming with TiO2-Cu photocatalysts bearing different Cu species
TiO2-Cu photocatalysts (1 wt.% Cu) containing different copper species have been prepared and used for the generation of hydrogen by photoreforming of cellulose (the major component of biomass) in water at room temperature, using UV light. A positive effect of copper has been clearly observed, and the analysis of the role of the Cu species present shows that a mixture of Cu(I) and Cu(II) favours the process. Among the TiO2-Cu photocatalysts, the one prepared by a simple impregnation method and not heat-treated, which shows small and well dispersed copper species particles, gives the highest hydrogen production.This work was supported by the national and regional Spanish governments (RTI2018-095291-B-100, PID2021-123079OB-I00 and CIPROM/2021/070) and the University of Alicante (VIGROB-136)
Efficient and labor-saving Ru/C catalysts for the transformation of levulinic acid into γ-valerolactone under mild reaction conditions
Ru/C catalysts for the transformation of levulinic acid into gamma-valerolactone have been prepared using carbon materials with different textural and chemical properties, and morphology. In the mild reaction conditions used (70 °C, 15 bar H2, 1 h), all the reduced catalysts are active and selective, with similar behavior independently of the support's properties. Surprisingly, the un-reduced (as prepared) catalysts show also catalytic activity, which varies (from moderate to high) with the carbon support type, indicating that an in situ (under reaction) reduction process takes place. The catalysts prepared with the supports of lower surface chemistry are almost as active as their reduced counterparts, whereas those prepared with rich surface chemistry supports are noticeably less active, but become activated in consecutive runs. The size of the developed Ru particles depends on the reduction conditions (i.e., reduction treatment at 250 °C or reaction conditions) and is highly influenced by the support's surface chemistry, which determines the metal–support interaction.This work was supported by the following research projects: RTI2018–095291-B-100 and PID2021–123079OB-I00 (project funded by MICINN/AEI/10.13039/501100011033 and by ERDF A way of making Europe (European Union)), CIPROM/2021/070 (Generalitat Valenciana) and VIGROB-136 (University of Alicante). Z. R.-B. thanks MICINN for the pre-doctoral scholarship (PRE2019-090049). The authors thank Immutrix Therapeutics and Ingevitiy Corporation (both in the USA) for providing carbon materials. The research technical services of the University of Alicante and the University of Cádiz (both in Spain) are also acknowledged
Combined precoding for multiuser Multiple-Input Multiple-Output satellite communications
[EN] Applying Multiple-Input Multiple-Output (MIMO) techniques in satellite communications can increase data rates. However, new signal processing elements have to be taken into account to fully exploit the expected advantages of MIMO communications. In this paper, we evaluate different precoding techniques over the satellite channel. A performance comparison between several precoders in terms of Bit Error Rate (BER) and complexity is given for different channel realizations. Furthermore, a novel hybrid scheme for signal precoding is proposed that optimizes the computation for a required BER. The new scheme is based on the matrix condition number of the satellite MIMO channel.This work has been partially funded by the Spanish MINECO grant RACHEL TEC2013-47141-C4-4-R and through FPU AP-2012/71274.Simarro, MA.; Puig, B.; Martínez Zaldívar, FJ.; Gonzalez, A. (2018). Combined precoding for multiuser Multiple-Input Multiple-Output satellite communications. Computers & Electrical Engineering. 71:704-713. https://doi.org/10.1016/j.compeleceng.2018.08.006S7047137
Mesoporous Activated Carbon Supported Ru Catalysts to Efficiently Convert Cellulose into Sorbitol by Hydrolytic Hydrogenation
Catalysts consisting of Ru nanoparticles (1 wt%), supported on mesoporous activated carbons (ACs), were prepared and used in the one-pot hydrolytic hydrogenation of cellulose to obtain sorbitol. The carbon materials used as supports are a pristine commercial mesoporous AC (named SA), and two samples derived from it by sulfonation or oxidation treatments (named SASu and SAS, respectively). The catalysts have been thoroughly characterized regarding both surface chemistry and porosity, as well as Ru electronic state and particle size. The amount and type of surface functional groups in the carbon materials becomes modified as a result of the Ru incorporation process, while a high mesopore volume is preserved upon functionalization and Ru incorporation. The prepared catalysts have shown to be very active, with cellulose conversion close to 50% and selectivity to sorbitol above 75%. The support functionalization does not lead to an improvement of the catalysts’ behavior and, in fact, the Ru/SA catalyst is the most effective one, with about 50% yield to sorbitol, and a very low generation of by-products.This research was funded by Spanish Ministry of Science, Innovation and Universities and FEDER, project of reference RTI2018-095291-B-I00, GV/FEDER (PROMETEO/2018/076) and University of Alicante (VIGROB-136)
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