Can Fixed-Term Contracts Put Low Skilled Youth on a Better Career Path? Evidence from Spain

By reducing the commitment made by employers, fixed-term contracts can help low-skilled youth find a first job. However, the long-term impact of fixed-term contracts on these workers' careers may be negative. Using Spanish social security data, we analyze the impact of a large liberalization in the regulation of fixed-term contracts in 1984. Using a cohort regression discontinuity design, we find that the reform raised the likelihood of male high-school dropouts working before age 19 by 9%. However, in the longer run, the reform reduced number of days worked (by 4.5%) and earnings (by 9%)

A Synchronous Reference Frame Robust Predictive Current Control for Three-Phase Grid-Connected Inverters

This paper presents a new predictive current control for three-phase grid-connected inverters in the synchronous reference frame. The control combines a deadbeat control law with a diagonal  Luenberger observer to estimate the future value of the grid currents. It provides a decoupled control of the active and reactive power and offers robustness against the computational delay inherent in the digital implementation and against filter and grid-impedance uncertainties. This control exhibits a very fast current response while widely improving the gain and phase margins of the traditional predictive controllers.Fil: Espi Huerta, J.M.. Universidad de Valencia; EspañaFil: Castello Moreno, J.. Universidad de Valencia; EspañaFil: Fischer, Jonatan Roberto. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Electrónica. Laboratorio de Instrumentación y Control; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Garcia Gil, R.. Universidad de Valencia; Españ

Response Surface Optimization of Inulin and Polyphenol Extraction from Artichoke (Cynara scolymus (L.)) Solid Wastes

[EN] Featured Application Recovery of bioactive compounds from artichoke solid wastes. Artichoke wastes after processing represent 60-70% of the raw material and are a potential source of inulin and polyphenols, bioactive compounds that can be valorized as food ingredients or nutraceutical products. The aim of this work was to assess and optimize the extraction of these compounds from artichoke wastes using water or water-ethanol mixtures as extracting agents. For simultaneous inulin and polyphenol extraction and to achieve high antioxidant activity in extracts, the best process conditions using water as an extracting agent were T = 89 degrees C and t = 139 min, where 80% of the inulin content, 60% of the total phenolic content (TPC) and 56% of the antioxidant activity (Aox) were obtained. For water-ethanol extractions, the best results were obtained with EtOH = 22.4%, T = 81 degrees C and t = 217 min, leading to extraction yields of 90% of TPC, 38% of Aox and 58% of inulin content. From these results, we recommend the use of water for the recovery of inulin and polyphenols from artichoke wastes. Although the extraction yield of polyphenols is lower in water treatments, the amount extracted is considerable and it is a greener option when compared with water-ethanol mixtures.Garcia-Castello, EM.; Mayor, L.; Calvo-Ramirez, A.; Ruiz-Melero, R.; Rodríguez López, AD. (2022). Response Surface Optimization of Inulin and Polyphenol Extraction from Artichoke (Cynara scolymus (L.)) Solid Wastes. Applied Sciences. 12(6):1-15. https://doi.org/10.3390/app1216795711512

Characterization of Ionic Exchange and Macroporous Resins for Their Application on the Separation and Recovery of Chlorogenic Acid from the Wastewater of Artichoke Blanching

[EN] Food wastes have traditionally been considered as dead-end materials; however, recent international, national, and regional policies strongly promote the use of these wastes as potential resources. This change of perception considers the need for sustainable exploitation of natural resources. In this context, artichoke processing produces high amounts of wastewaters, and specifically, wastewaters from the artichoke blanching step present a high content of valuable biocomponents such as carbohydrates and phenolic compounds (e.g., chlorogenic acid, 1700 ppm). In this work, the recovery of chlorogenic acid by applying sorption processes was studied. Five resins were tested, and it was found that the resin XAD 7 HP presented the best total adsorption-desorption yield (72.8%) at 20 degrees C. It was also found that there was a strong variation of the adsorption ratio depending on solution pH (3-7). Four models of isotherms were applied to the adsorption processes, and the Langmuir isotherm better explained the adsorption behavior. The kinetic study showed that the adsorption and desorption of chlorogenic acid followed a pseudo-second order model where the kinetic constant depended on the adsorbate concentration. In addition, it was found that the sorption process was controlled by more than just the intraparticle diffusion mechanism.Rodríguez López, AD.; Reig Riera, MM.; Mayor, L.; Ortiz-Climent, M.; Garcia-Castello, EM. (2021). Characterization of Ionic Exchange and Macroporous Resins for Their Application on the Separation and Recovery of Chlorogenic Acid from the Wastewater of Artichoke Blanching. Sustainability. 13(16):1-15. https://doi.org/10.3390/su13168928S115131

Activated-Carbon-Doped Non-Solvent-Induced Phase-Inversion Membranes : A Comprehensive Study on Synthesis, Characterisation, and Performance Evaluation

Acknowledgments: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. For the purpose of open access, the author has applied a Creative Commons Attribution (CC-BY) licence to any Author-Accepted Manuscript version arising from this submission For the purpose of open access, the author has applied a Creative Commons Attribution (CC-BY) licence to any Author Accepted Manuscript version arising from this submission.Peer reviewedPublisher PD

Fabrication and performance of low-fouling UF membranes for 2 the treatment of Isolated Soy Protein solutions

[EN] Consumers are becoming more conscious about the need to include functional and nutritional foods in their diet. This has increased the demand for food extracts rich in proteins and peptides with physiological effects that are used within the food and pharmaceutical industries. Among these protein extracts, soy protein and its derivatives are highlighted. Isolated soy protein (ISP) presents a protein content of at least 90%. Wastewaters generated during the production process contain small proteins (8-50 kDa), and it would be desirable to find a recovery treatment for these compounds. Ultrafiltration membranes (UF) are used for the fractionation and concentration of protein solutions. By the appropriate selection of the membrane pore size, larger soy proteins are retained and concentrated while carbohydrates and minerals are mostly recovered in the permeate. The accumulation and concentration of macromolecules in the proximity of the membrane surface generates one of the most important limitations inherent to the membrane technologies. In this work, three UF membranes based on polyethersulfone (PES) were fabricated. In two of them, polyethylene glycol (PEG) was added in their formulation to be used as a fouling prevention. The membrane fouling was evaluated by the study of flux decline models based on Hermia's mechanisms.The Universitat Politecnica de Valencia (Spain), through the project 2623 (PAID-05-10), funded this research.Garcia-Castello, EM.; Rodríguez López, AD.; Barredo Damas, S.; Iborra Clar, A.; Pascual-Garrido, J.; Iborra-Clar, MI. (2021). Fabrication and performance of low-fouling UF membranes for 2 the treatment of Isolated Soy Protein solutions. Sustainability. 13(24):1-16. https://doi.org/10.3390/su132413682S116132

Adverse birth outcomes in the vicinity of industrial installations in Spain 2004-2008

Industrial activity is one of the main sources of ambient pollution in developed countries. However, research analyzing its effect on birth outcomes is inconclusive. We analyzed the association between proximity of mother's municipality of residence to industries from 24 different activity groups and risk of very (VPTB) and moderate (MPTB) preterm birth, very (VLBW) and moderate (MLBW) low birth weight, and small for gestational age (SGA) in Spain, 2004-2008. An ecological study was defined, and a "near vs. far" analysis (3.5 km threshold) was carried out using Hierarchical Bayesian models implemented via Integrated Nested Laplace Approximation. VPTB risk was higher for mothers living near pharmaceutical companies. Proximity to galvanization and hazardous waste management industries increased the risk of MPTB. Risk of VLBW was higher for mothers residing near pharmaceutical and non-hazardous or animal waste management industries. For MLBW many associations were found, being notable the proximity to mining, biocides and animal waste management plants. The strongest association for SGA was found with proximity to management animal waste plants. These results highlight the importance of further research on the relationship between proximity to industrial sites and the occurrence of adverse birth outcomes especially for the case of pharmaceutical and animal waste management activities.We would like to acknowledge the support of the Fondo de Investigación Sanitaria (PI081330), Spanish Ministry of Science and Innovation (SEJ 2005/07679 and CD11/00018), and the CIBER en Epidemiología y Salud Pública (CIBERESP), Spain.S

By-product recovery of Opuntia spp. peels: Betalainic and phenolic profiles and bioactive properties

[EN] Opuntia spp. are a tropical and subtropical plant that provides both edible green steams and fruits; however, the processing of this fruits results in the accumulation of enormous amount of by-products that can be a source of bioactive and pigmented compounds. Herein, three cactus pear from the species Opuntia focus-indica var. sanguigna (OS) and gialla (OG) and Opuntia engelmannii (OE) were fully characterized regarding their phenolic and betalain composition and correlated with their antioxidant and antimicrobial activities. The hydroethanolic extracts of OE gave the highest amount of phenolic compounds isorhamentin-O-(deoxyhexosyl-hexoside) and betacianins (betanin); however, no betaxanthins were identified in this sample. This sample also revealed the lowest EC50 values in all the antioxidant activity assays. Regarding antimicrobial activity, the hydroethanolic extracts of all species revealed to be more active than ampicillin. The pivotal objective of this work was to focus on exploring by-product biocompounds and possible outputs, thus, we could suggest the use of these natural colorants with intrinsic antioxidant and antimicrobial activity, which would grant industries to produce cleaner label products with functional benefits.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2013) and L. Barros contract. This work is funded by the European Structural and Investment Funds (FEEI) through the Regional Operational Program North 2020, within the scope of Project NORTE-01-0145-FEDER-023289 (DeCodE) and ValorNatural (R). B. Melgar (No. 329930) also thanks CONACyT for his grant. The authors are grateful for a grant from the Serbian Ministry of Education, Sciences and Technological Development (no. 173032). The authors would also like to thank Dr. Carlos Aguiar for the botanical identification of these species.Melgar-Castañeda, B.; Dias, MI.; Ciric, A.; Sokovic, M.; Garcia-Castello, EM.; Rodríguez López, AD.; Barros, L.... (2017). By-product recovery of Opuntia spp. peels: Betalainic and phenolic profiles and bioactive properties. Industrial Crops and Products. 107:353-359. https://doi.org/10.1016/j.indcrop.2017.06.011S35335910