Driving the transition to a circular economic model: A systematic review on drivers and critical success factors in circular economy

The circular economy (CE) is arising as a novel economic system that is restorative by design. In light of its capability to boost sustainable economic development and to cope with environmental challenges, it has recently attracted increasing attention from academics, practitioners, policymakers, and intergovernmental organizations. Despite the wide speculation on this issue, the scientific literature lacks a wide-ranging, systematic, and updated identification and classification of the main drivers and Critical Success Factors of CE initiatives, which appears increasingly necessary to facilitate future scientific work, practical implementations, and policy guidelines. With this aim, this paper develops a systematic literature review by starting with over 400 manuscripts. A final set of 55 selected papers was selected for singling out and classifying drivers and Critical Success Factors in the CE context. The results may provide clear indications for further research, may help business organizations in evaluating CE initiatives, and may guide policy makers in developing and refining CE normative frameworks

Desarrollo e implementación de un hormigón reforzado con fibras sintéticas para la repavimentación de la Ruta 24 de Uruguay

Los pavimentos de hormigón son estructuras propensas a la fisuración. El uso de fibras aparece como una de las mejores alternativas técnico-económicas para mejorar el comportamiento del hormigón. Una de las aplicaciones del Hormigón Reforzado con Fibras (HRF) es la reparación o refuerzo (“overlays”) de antiguos pavimentos. En la actualidad se dispone de macrofi bras sintéticas que pueden utilizarse en este tipo de aplicaciones en lugar de las tradicionales fi bras de acero. Este trabajo transmite la experiencia adquirida durante la ejecución de la rehabilitación de la Ruta 24 en Uruguay empleando un “whitetopping” delgado (adherido) de HRF. Se describen los resultados obtenidos durante el control de calidad en obra y se discuten los principales desafíos durante la ejecución como el uso de un aditivo reductor de agua de alto rango, el empleo de tecnología de alto rendimiento y el logro de una adecuada adherencia HRF – sustrato asfáltico.Fil: Miguez Pessada, D.. Hormigones Artigas S.A.; UruguayFil: Gonzalez, A. C. Hormigones Artigas S.A.; UruguayFil: Violini, D.. Cementos Avellaneda S.A; ArgentinaFil: Pappalardi, M.. Cementos Avellaneda S.A.; ArgentinaFil: Zerbino, Raul Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ingeniería. Departamento de Construcciones; Argentin

Simultaneous genome sequencing of symbionts and their hosts

Second-generation sequencing has made possible the sequencing of genomes of interest for even small research groups. However, obtaining separate clean cultures and clonal or inbred samples of metazoan hosts and their bacterial symbionts is often difficult. We present a computational pipeline for separating metazoan and bacterial DNA in silico rather than at the bench. The method relies on the generation of deep coverage of all the genomes in a mixed sample using Illumina short-read sequencing technology, and using aggregate properties of the different genomes to identify read sets belonging to each. This inexpensive and rapid approach has been used to sequence several nematode genomes and their bacterial endosymbionts in the last year in our laboratory and can also be used to visualize and identify unexpected contaminants (or possible symbionts) in genomic DNA samples. We hope that this method will enable researchers studying symbiotic systems to move from gene-centric to genome-centric approaches

Sequence Ontology terminology for gene regulation

The Sequence Ontology (SO) is a structured, controlled vocabulary that provides terms and definitions for genomic annotation. The Gene Regulation Ensemble Effort for the Knowledge Commons (GREEKC) initiative has gathered input from many groups of researchers, including the SO, the Gene Ontology (GO), and gene regulation experts, with the goal of curating information about how gene expression is regulated at the molecular level. Here we discuss recent updates to the SO reflecting current knowledge. We have developed more accurate human-readable terms (also known as classes), including new definitions, and relationships related to the expression of genes. New findings continue to give us insight into the biology of gene regulation, including the order of events, and participants in those events. These updates to the SO support logical reasoning with the current understanding of gene expression regulation at the molecular level

Recommendation of RILEM TC 261-CCF: test method to determine the flexural creep of fibre reinforced concrete in the cracked state

[EN] To date there is no clear consensus about how creep of cracked FRC structural elements should be considered. In recent years, different methodologies have been developed for multiple stress cases. The absence of a standardised methodology to evaluate flexural creep in the cracked state has hindered general comparisons and conclusions that could lead to significant advances in this topic. Since 2014, the study of the creep behaviour of cracked FRC has been coordinated by the RILEM TC 261-CCF. All the available creep methodologies were analysed in terms of procedure, equipment and results. A comprehensive Round-Robin Test (RRT) on the creep behaviour of cracked sections of FRC was proposed and undertaken by a total of 19 participant laboratories from 14 countries all over the world. The analysis and conclusions of the RRT results and the different methodologies provided the basis for this recommendation. This recommendation focuses on the test method to evaluate the flexural creep of FRC specimens in the cracked state. Guidelines on specimen production, detailed test equipment, experimental setup and test procedure as well as the definitions of the most relevant parameters are provided.Llano-Torre, A.; Serna Ros, P. (2021). Recommendation of RILEM TC 261-CCF: test method to determine the flexural creep of fibre reinforced concrete in the cracked state. Materials and Structures. 54(3):1-20. https://doi.org/10.1617/s11527-021-01675-0S120543Theodorakopoulos D (1995) Creep characteristics of glass reinforced cement under flexural loading. Cement Concr Compos 17:267–279Chanvillard G, Roque O (1999) Behaviour of fibre reinforced concrete cracked section under sustained load. High Performance Fiber Reinforced Cement Composites (HPFRCC 3) Mainz, Germany, pp 239–250, RILEM PRO 06Kurt S, Balaguru P (2000) Post crack creep of polymeric fibre-reinforced concrete in flexure. Cem Concr Res 30(2):183–190Mackay J, Trottier JF (2004) Post-crack behavior of steel and synthetic FRC under flexural creep. In: Shotcrete, Proc. 2nd Intnl. Conf. on Engineering, Cairns, Australia (2004), pp 183–192Kusterle W (2009) Viscous material behaviour of solids- creep of polymer fibre reinforced concrete. In: Proc. 5th Central European Congress on Concrete Engineering. obv, Baden, pp 95–100Arango S, Serna P, Martí-Vargas JR, García-Taengua E (2012) A test method to characterize flexural creep behaviour of pre-cracked FRC specimens. Exp Mech 52(8):1067–1078Zerbino RL, Barragan BE (2012) Long-term behaviour of cracked steel fibre-reinforced concrete beams under sustained loading. ACI Mater J 109(2):215–224Abrishambaf A, Barros JAO, Cunha VMCF (2015) Time-dependent flexural behaviour of cracked steel fibre reinforced self-compacting concrete panels. Cem Concr Res 72:21–36Buratti N, Mazzotti C (2016) Experimental tests on the long-term behaviour of SFRC and MSFRC in bending and direct tension. In: Proceedings of the BEFIB 2016, 9th RILEM international symposium on fiber reinforced concrete, pp. 163–174, Vancouver, Canada, 19–21 Sept 2016Babafemi AJ, Boshoff WP (2015) Tensile creep of macro-synthetic fibre reinforced concrete (MSFRC) under uni-axial tensile loading. Cement Concr Compos 55:62–69Vrijdaghs R, di Prisco M, Vandewalle L (2018) Uniaxial tensile creep of a cracked polypropylene fiber reinforced concrete. Mater Struct 51:5. https://doi.org/10.1617/s11527-017-1132-5Vasanelli E, Micelli F, Aiello MA, Plizzari G (2013) Long term behaviour of FRC flexural beams under sustained load. Eng Struct 56:1858–1867Bernard ES (2010) Influence of fibre type on creep deformation of cracked fibre-reinforced shotcrete panels. ACI Mater J 107(5):474–480EFNARC (2012) Testing sprayed concrete—Creep test on square panelLarive C, Rogat D, Chamoley D, Regnard A, Pannetier T, Thuaud C (2016) Influence of fibres on the creep behaviour of reinforced sprayed concrete. In: Proceedings of ITA World Tunnel Congress WTC 2016, April 22‐28, San Francisco, United StatesMonetti DH, Llano-Torre A, Torrijos MC, Giaccio G, Zerbino R, Martí-Vargas JR, Serna P (2019) Long-term behavior of cracked fiber reinforced concrete under service conditions. Construct Build Mater; 196:649–658. https://doi.org/10.1016/j.conbuildmat.2018.10.230Llano-Torre A., Martí-Vargas JR, Serna P (2020) Flexural and compressive creep behavior of UHPFRC specimens. Construct Build Mater; 244:118254. https://doi.org/10.1016/j.conbuildmat.2020.118254Serna P, Llano-Torre A and Cavalaro S H P (ed) (2017) Creep behaviour in cracked sections of fibre reinforced concrete: proceedings of the international RILEM Workshop FRC-CREEP 2016. RILEM bookseries 14 (Dordrecht: Springer)Llano-Torre A, Serna P, Cavalaro SHP (2016) International round robin test on creep behavior of FRC supported by the RILEM TC 261-CCF. In: Proceedings of the BEFIB 2016, 9th RILEM international symposium on fiber reinforced concrete, pp 127–140, Vancouver, Canada, 19–21 Sept 2016Serna P, Llano-Torre A, García-Taengua E, Martí-Vargas JR (2015) Database on the long-term behaviour of FRC: a useful tool to achieve overall conclusions. In: Proceedings of the 10th international conference on mechanics and physics of Creep, Shrinkage, and Durability of Concrete and Concrete Structures, Vienna, September 2015, pp 1544–1553Llano-Torre A., Serna P. (eds) Round-Robin test on creep behaviour in cracked sections of FRC: experimental program, results and database analysis. RILEM State-of-the-Art Reports. Springer. https://doi.org/10.1007/978-3-030-72736-9ASTM International (2015) C1812/C1812M-15e1 Standard Practice for Design of Journal Bearing Supports to be Used in Fiber Reinforced Concrete Beam Tests. West Conshohocken, PA; ASTM International. https://doi.org/10.1520/C1812_C1812M-15E0

Desarrollo e implementación de un hormigón reforzado con fibras sintéticas para la repavimentación de la Ruta 24 de Uruguay

Los pavimentos de hormigón son estructuras propensas a la fisuración. El uso de fibras aparece como una de las mejores alternativas técnico-económicas para mejorar el comportamiento del hormigón. Una de las aplicaciones del Hormigón Reforzado con Fibras (HRF) es la reparación o refuerzo (“overlays”) de antiguos pavimentos. En la actualidad se dispone de macrofi bras sintéticas que pueden utilizarse en este tipo de aplicaciones en lugar de las tradicionales fi bras de acero. Este trabajo transmite la experiencia adquirida durante la ejecución de la rehabilitación de la Ruta 24 en Uruguay empleando un “whitetopping” delgado (adherido) de HRF. Se describen los resultados obtenidos durante el control de calidad en obra y se discuten los principales desafíos durante la ejecución como el uso de un aditivo reductor de agua de alto rango, el empleo de tecnología de alto rendimiento y el logro de una adecuada adherencia HRF – sustrato asfáltico.Facultad de IngenieríaLaboratorio de Entrenamiento Multidisciplinario para la Investigación Tecnológic

Orientando el aprendizaje al desarrollo de destrezas y habilidades tecnológicas

Se discuten los lineamientos de una experiencia de laboratorio propuesta y desarrollada por alumnos de Física de la UTN (FRLP), cuyo eje es la motivación y autodeterminación para su realización y que culmina en la adquisición y profundización de conocimientos, competencias y repaso de contenidos sobre un tema tratado previamente. Por iniciativa propia los alumnos realizaron la experiencia y la cátedra actuó como tutora. En este proceso abarcativo la participación activa del alumno para explicar lo observado utilizando conceptos adquiridos, permite evaluar el aprendizaje significativo. El fenómeno físico fundamental es “Reflexión Interna Total”. La metodología utilizada estimuló la curiosidad sobre detalles de diseño que no están presentes cuando se realiza un trabajo de laboratorio tradicional y contribuyó a desarrollar habilidades para resolver problemas y necesidades tecnológicas que trascienden las fronteras del aula. Se describen los aspectos más importantes de la evolución del grupo respecto a la interpretación de las observaciones, y cómo la guía del docente, planteando enigmas, confrontando resultados e ideas y sinopsis, permite, además, desarrollar el sentido crítico y las destrezas experimentales, en una experiencia considerada a priori “muy sencilla” por los alumnos. Se pone en evidencia la importancia de la experimentación real y concreta como complemento insustituible en la enseñanza de las ciencias naturales.The tendencies of a laboratory experience suggested and developed by students of a Physics Professorship of the UTN (FRLP) are discussed. Its vehicle is the motivation and self-determination for its development which ends up in the acquisition and the deepening of knowledge, abilities and skills as well as a revision of content based on previous topics. In the experience, it was the students themselves, as a result of their own initiative, who carried out the experience while the professors acted as tutors. This comprehensive process requires active student participation to explain what has been observed in the laboratory, using the concepts, to acquire significant learning. The procedure, lined at the beginning, then enables the spontaneous evolution of the students. The main physical phenomenon is that of the ‘Total Internal Reflection´. The spontaneous suggestion aroused the students’ curiosity on aspects concerned in the carrying out of the experience, which are not evidenced in a traditiomal laboratory work. This factor helps us develop abilities and skills in research to solve problems and technological needs which go beyond the class. The main aspects of the party’s progress, as regards the interpretation of observations and the instructions of the professor, built on bases of setting out enigma, resulting confrontations and ideas and summaries are described. At the same time, enable us to assess meaningful learning and to develop a critical sense and abilities and skills from an experience considered a priori as ‘very simple’ by students. This case is a clear evidence of the importance of real and concrete experimentation as an unavoidable complement in the learning of the natural sciences.Facultad de Ingenierí

Healthcare-associated outbreak of meticillin-resistant Staphylococcus aureus bacteraemia: role of a cryptic variant of an epidemic clone

BACKGROUND New strains of meticillin-resistant Staphylococcus aureus (MRSA) may be associated with changes in rates of disease or clinical presentation. Conventional typing techniques may not detect new clonal variants that underlie changes in epidemiology or clinical phenotype. AIM To investigate the role of clonal variants of MRSA in an outbreak of MRSA bacteraemia at a hospital in England. METHODS Bacteraemia isolates of the major UK lineages (EMRSA-15 and -16) from before and after the outbreak were analysed by whole-genome sequencing in the context of epidemiological and clinical data. For comparison, EMRSA-15 and -16 isolates from another hospital in England were sequenced. A clonal variant of EMRSA-16 was identified at the outbreak hospital and a molecular signature test designed to distinguish variant isolates among further EMRSA-16 strains. FINDINGS By whole-genome sequencing, EMRSA-16 isolates during the outbreak showed strikingly low genetic diversity (P < 1 × 10(-6), Monte Carlo test), compared with EMRSA-15 and EMRSA-16 isolates from before the outbreak or the comparator hospital, demonstrating the emergence of a clonal variant. The variant was indistinguishable from the ancestral strain by conventional typing. This clonal variant accounted for 64/72 (89%) of EMRSA-16 bacteraemia isolates at the outbreak hospital from 2006. CONCLUSIONS Evolutionary changes in epidemic MRSA strains not detected by conventional typing may be associated with changes in disease epidemiology. Rapid and affordable technologies for whole-genome sequencing are becoming available with the potential to identify and track the emergence of variants of highly clonal organisms

A robust SNP barcode for typing Mycobacterium tuberculosis complex strains

Strain-specific genomic diversity in the Mycobacterium tuberculosis complex (MTBC) is an important factor in pathogenesis that may affect virulence, transmissibility, host response and emergence of drug resistance. Several systems have been proposed to classify MTBC strains into distinct lineages and families. Here, we investigate single-nucleotide polymorphisms (SNPs) as robust (stable) markers of genetic variation for phylogenetic analysis. We identify ~92k SNP across a global collection of 1,601 genomes. The SNP-based phylogeny is consistent with the gold-standard regions of difference (RD) classification system. Of the ~7k strain-specific SNPs identified, 62 markers are proposed to discriminate known circulating strains. This SNP-based barcode is the first to cover all main lineages, and classifies a greater number of sublineages than current alternatives. It may be used to classify clinical isolates to evaluate tools to control the disease, including therapeutics and vaccines whose effectiveness may vary by strain type