Evaluación ambiental y económica de la utilización de materiales reciclados para la producción de hormigón estructural y no estructural en Cataluña

Los residuos de construcción y demolición (RCD) presentan un grave problema ambiental a nivel mundial, ya que en su mayoría, estos residuos terminan en vertederos o depósitos incontrolados, provocando grandes agravantes ambientales. Se conoce que Cataluña es la primera Comunidad Autónoma de España que genera mayor producción de residuos de construcción y demolición, por lo que en este estudio se plantea realizar una evaluación para conocer la diferencia en cuanto a la realización de un hormigón convencional (con áridos naturales) y dos alternativas de hormigón con distintos porcentajes de áridos reciclados (25% y 50% respectivamente), tanto ambiental como económico, para conocer las alternativas de mejora a este problema. La evaluación ambiental se realiza a través de una metodología de análisis de ciclo de vida, mientras que el análisis económico se realiza por medio de una economía lineal y el desarrollo de un indicador que representa el rendimiento de una economía circular. La unidad funcional empleada para la metodología de análisis de ciclo de vida es 1m3 de hormigón, tanto de árido natural como las otras dos alternativas que se agregan los áridos reciclados descritos anteriormente, tanto para hormigón estructural como no estructural. Para los áridos reciclados, se le da importancia al tipo de residuo utilizado en la planta de reciclaje, que proviene exclusivamente de residuos de hormigón; se asume que el proceso de reciclaje se realiza por medio de la planta fija de Les Franqueses del Vallés. Los resultados indican que al comparar el hormigón convencional con hormigón estructural con 25% de áridos reciclados, este último presenta la mayor cantidad de impactos ambientales debido a que los áridos naturales (que son un 75%), generan la extracción de minerales pero también por los áridos reciclados ya que se emplean grandes energías y transporte para su movilización. En cuanto al aspecto económico, el de menor coste es el hormigón estructural con 25% de áridos naturales, esto es debido a la gran diferencia de coste entre el árido natural y el árido reciclado, aunque al producir 1m3 de hormigón, en ambos casos el cemento es el material que mayor coste implica, generando aproximadamente el 50% del coste total de la producción del hormigón. Al comparar el hormigón convencional con hormigón no estructural con 50% de áridos reciclados, este último presenta la mayor cantidad de impactos ambientales debido a que los áridos naturales (que son un 50%), generan la extracción de minerales y presentan grandes impactos en cuanto a la salud humana, pero también por los áridos reciclados ya que se emplean grandes energías y transporte para su movilización. En cuanto al aspecto económico, el de menor coste es el hormigón estructural con 50% de áridos naturales, esto es debido a la gran diferencia de coste entre el árido natural y el árido reciclado, que en esta comparación se puede apreciar mejor ya que el árido reciclado llega a un 50%. Los índices de rendimiento de la economía circular indican que actualmente, el rendimiento de las dos alternativas de áridos reciclados tienen aproximadamente un 68%-69% de reutilización de los residuos, esto implica que parte de los residuos, no se reutilizan y en una economía circular todos los residuos deben de reutilizarse de ser posible en un 100%. Los resultados indican que en cuanto a la metodología de análisis de ciclo de vida, específicamente para este estudio y tomando en cuenta las especificaciones del estudio, el hormigón estructural con 25% de árido reciclado y el hormigón no estructural con 50% de árido reciclado no son viables en comparación con un hormigón convencional, debido a los grandes impactos medioambientales que presentan. Mientras que en cuanto al análisis económico los hormigones que presentan áridos reciclados son más viables en comparación con el hormigón convencional. Esto es debido al precio de los áridos reciclados en comparación con los áridos naturales.Construction and demolition waste (CDW) present serious environmental problems worldwide, and most of these wastes end up in landfills or uncontrolled deposits, causing great environmental aggravation. It is known that Catalonia is the first Autonomous Community of Spain that generates an important production of construction and demolition waste, this is why in this study it is proposed the analysis of an environmental evaluation, to know the difference in the realization of a conventional concrete (with natural aggregates ) and two alternatives of concrete with different percentages of recycled aggregates (25% and 50%, respectively), and an economic evaluation, to determine the alternatives to improve this problem. The environmental assessment is carried out through a life cycle analysis methodology, while the economic analysis is performed through a linear economy and the development of an indicator that represents the performance of a circular economy. The functional unit used for the methodology of life cycle analysis is 1m3 of concrete, for natural arid and also for other two alternatives that have recycled aggregates for structural and non-structural concrete. For recycled aggregates, importance is given to the type of waste used in the recycling plant, which comes exclusively from concrete waste; it is assumed that the recycling process is carried out through the fixed plant of Les Franqueses del Vallés. The results indicate that when comparing conventional concrete with structural concrete with 25% of recycled aggregates, the greatest amount of environmental impacts is produced by the structural concrete with 25% of recycled aggregates due to the fact that natural aggregates (75%) generate mineral extraction, but also the recycled aggregates, since they use energies and transport for their mobilization. As for the economic aspect, the lowest cost is the structural concrete with 25% of natural aggregates, this is due to the great cost difference between the natural aggregate and the recycled aggregate, although producing 1m3 of concrete, in both cases cement is the material that carries the highest cost, generating approximately 50% of the total cost of production of the concrete. When comparing conventional concrete with non-structural concrete with 50% of recycled aggregates, the non-structural concrete presents the greatest amount of environmental impacts due to the fact that natural aggregates (which are 50%), generate mineral extraction and have large impacts as to human health, but also for the recycled aggregates, since they use energies and transport for their mobilization. As for the economic aspect, the lowest cost is the structural concrete with 50% of natural aggregates, this is due to the great cost difference between the natural aggregate and the recycled aggregate, which in this comparison can be better appreciated since the recycled aggregate reaches 50%. The rating performance of the circular economy indicate that the yields of the two recycled aggregate alternatives are currently between 68% and 69% of waste reuse, which means that some of the waste is not reused and in the circular economy, all waste must be reused if possible by 100%. The results indicate that in terms of the life cycle analysis methodology, specifically for this study and taking into account the specifications, structural concrete with 25% recycled aggregate and non-structural concrete with 50% recycled aggregate are not viable compared to conventional concrete, due to the large environmental impacts they present. Whereas in the economic analysis the concrete that present recycled aggregates are more viable in comparison with the conventional concrete. This is due to the price of recycled aggregates compared to natural aggregates

Application of the techniques of gravity center and AHP for the location of a distribution center for industrial products in Colombia

Este artículo presenta un estudio de aplicación de las metodologías de Centro de gravedad y Modelo AHP, con el fin de proponer la mejor ubicación para un centro de distribución, en vez de tener múltiples almacenes independientes, para una empresa comercializadora de productos industriales en Colombia. Como caso práctico de estudio, se utilizan los datos de una empresa comercializadora de productos industriales, con ocho sucursales a nivel nacional, donde no hay políticas claras en el manejo de la mercancía y mucho menos, en el movimiento de esta entre las diferentes sucursales.This paper presents an implementation study of the methodologies: Center of Gravity and AHP Model, with the aim of suggesting the best location for a distribution center, instead of having multiple independent stores, for a marketing company of industrial products in Colombia. As a practical case study, data from a marketing company of industrial products are used. This company has eight branches nationwide and it has no clear policies about the handling of goods and even less clear about the transportation of them among the different branches

Practical context of enzymatic treatment for wound healing: A secreted protease approach (Review)

Skin wounds have been extensively studied as their healing represents a critical step towards achieving homeostasis following a traumatic event. Dependent on the severity of the damage, wounds are categorized as either acute or chronic. To date, chronic wounds have the highest economic impact as long term increases wound care costs. Chronic wounds affect 6.5 million patients in the United States with an annual estimated expense of $25 billion for the health care system. Among wound treatment categories, active wound care represents the fastest‑growing category due to its specific actions and lower costs. Within this category, proteases from various sources have been used as successful agents in debridement wound care. The wound healing process is predominantly mediated by matrix metalloproteinases (MMPs) that, when dysregulated, result in defective wound healing. Therapeutic activity has been described for animal secretions including fish epithelial mucus, maggot secretory products and snake venom, which contain secreted proteases (SPs). No further alternatives for use, sources or types of proteases used for wound healing have been found in the literature to date. Through the present review, the context of enzymatic wound care alternatives will be discussed. In addition, substrate homology of SPs and human MMPs will be compared and contrasted. The purpose of these discussions is to identify and propose the stages of wound healing in which SPs may be used as therapeutic agents to improve the wound healing process.Fil: Avila Rodríguez, María Isabela. Instituto Tecnologico de Monterrey. Escuela de Ingenieria y Ciencias.; MéxicoFil: Meléndez Martínez, David. Instituto Tecnologico de Monterrey. Escuela de Ingenieria y Ciencias.; MéxicoFil: Licona Cassani, Cuauhtemoc. Instituto Tecnologico de Monterrey. Escuela de Ingenieria y Ciencias.; MéxicoFil: Aguilar Yañez, José Manuel. Instituto Tecnologico de Monterrey. Escuela de Ingenieria y Ciencias.; México. Scicore Medical SAPI de CV; MéxicoFil: Benavides, Jorge. Instituto Tecnologico de Monterrey. Escuela de Ingenieria y Ciencias.; MéxicoFil: Sanchez, Mirna Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Multidisciplinario de Biología Celular. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Multidisciplinario de Biología Celular. Universidad Nacional de La Plata. Instituto Multidisciplinario de Biología Celular; Argentin

Parameter estimation for Boolean models of biological networks

Boolean networks have long been used as models of molecular networks and play an increasingly important role in systems biology. This paper describes a software package, Polynome, offered as a web service, that helps users construct Boolean network models based on experimental data and biological input. The key feature is a discrete analog of parameter estimation for continuous models. With only experimental data as input, the software can be used as a tool for reverse-engineering of Boolean network models from experimental time course data.Comment: Web interface of the software is available at http://polymath.vbi.vt.edu/polynome

A fatal case series of Rocky Mountain spotted fever in Sonora, México

Introduction: Rocky Mountain spotted fever is a highly lethal infectious disease, particularly if specific treatment with doxycycline is given belatedly. Objective: To describe the clinical profile of fatal Rocky Mountain spotted fever cases in hospitalized patients in the state of Sonora, México. Materials and methods: We conducted a cross-sectional study on a series of 47 deaths caused by Rickettsia rickettsii from 2013 to 2016. The diagnosis of Rocky Mountain spotted fever was confirmed in a single blood sample by polymerase chain reaction (PCR) or by a four-fold increase in immunoglobulin G measured in paired samples analyzed by indirect immunofluorescence. Clinical and laboratory characteristics were compared stratifying subjects into two groups: pediatric and adult. Results: There were no differences in clinical characteristics between groups; petechial rash was the most frequent sign (96%), followed by headache (70%) and myalgia (67%). Although that doxycycline was administered before the fifth day from the onset of symptoms, death occurred in 55% of patients. In clinical laboratory, thrombocytopenia, and biomarkers of liver acute failure and acute kidney failure were the most frequent. Conclusion: Rocky Mountain spotted fever remains as one of the most lethal infectious diseases, which may be related not only to the lack of diagnostic suspicion and delayed administration of doxycycline, but to genotypic characteristics of Rickettsia rickettsii that may play a role in the variability of the fatality rate that has been reported in other geographical regions where the disease is endemic

Silencing Nociceptor Neurons Reduces Allergic Airway Inflammation

Lung nociceptors initiate cough and bronchoconstriction. To elucidate if these fibers also contribute to allergic airway inflammation, we stimulated lung nociceptors with capsaicin and observed increased neuropeptide release and immune cell infiltration. In contrast, ablating Nav1.8(+) sensory neurons or silencing them with QX-314, a charged sodium channel inhibitor that enters via large-pore ion channels to specifically block nociceptors, substantially reduced ovalbumin- or house-dust-mite-induced airway inflammation and bronchial hyperresponsiveness. We also discovered that IL-5, a cytokine produced by activated immune cells, acts directly on nociceptors to induce the release of vasoactive intestinal peptide (VIP). VIP then stimulates CD4(+) and resident innate lymphoid type 2 cells, creating an inflammatory signaling loop that promotes allergic inflammation. Our results indicate that nociceptors amplify pathological adaptive immune responses and that silencing these neurons with QX-314 interrupts this neuro-immune interplay, revealing a potential new therapeutic strategy for asthma

Variation in stem mortality rates determines patterns of above-ground biomass in Amazonian forests: implications for dynamic global vegetation models

Understanding the processes that determine above-ground biomass (AGB) in Amazonian forests is important for predicting the sensitivity of these ecosystems to environmental change and for designing and evaluating dynamic global vegetation models (DGVMs). AGB is determined by inputs from woody productivity [woody net primary productivity (NPP)] and the rate at which carbon is lost through tree mortality. Here, we test whether two direct metrics of tree mortality (the absolute rate of woody biomass loss and the rate of stem mortality) and/or woody NPP, control variation in AGB among 167 plots in intact forest across Amazonia. We then compare these relationships and the observed variation in AGB and woody NPP with the predictions of four DGVMs. The observations show that stem mortality rates, rather than absolute rates of woody biomass loss, are the most important predictor of AGB, which is consistent with the importance of stand size structure for determining spatial variation in AGB. The relationship between stem mortality rates and AGB varies among different regions of Amazonia, indicating that variation in wood density and height/diameter relationships also influences AGB. In contrast to previous findings, we find that woody NPP is not correlated with stem mortality rates and is weakly positively correlated with AGB. Across the four models, basin-wide average AGB is similar to the mean of the observations. However, the models consistently overestimate woody NPP and poorly represent the spatial patterns of both AGB and woody NPP estimated using plot data. In marked contrast to the observations, DGVMs typically show strong positive relationships between woody NPP and AGB. Resolving these differences will require incorporating forest size structure, mechanistic models of stem mortality and variation in functional composition in DGVMs

Variation in stem mortality rates determines patterns of above-ground biomass in Amazonian forests: implications for dynamic global vegetation models

This is the final version of the article. Available from Wiley via the DOI in this record.Understanding the processes that determine above-ground biomass (AGB) in Amazonian forests is important for predicting the sensitivity of these ecosystems to environmental change and for designing and evaluating dynamic global vegetation models (DGVMs). AGB is determined by inputs from woody productivity [woody net primary productivity (NPP)] and the rate at which carbon is lost through tree mortality. Here, we test whether two direct metrics of tree mortality (the absolute rate of woody biomass loss and the rate of stem mortality) and/or woody NPP, control variation in AGB among 167 plots in intact forest across Amazonia. We then compare these relationships and the observed variation in AGB and woody NPP with the predictions of four DGVMs. The observations show that stem mortality rates, rather than absolute rates of woody biomass loss, are the most important predictor of AGB, which is consistent with the importance of stand size structure for determining spatial variation in AGB. The relationship between stem mortality rates and AGB varies among different regions of Amazonia, indicating that variation in wood density and height/diameter relationships also influences AGB. In contrast to previous findings, we find that woody NPP is not correlated with stem mortality rates and is weakly positively correlated with AGB. Across the four models, basin-wide average AGB is similar to the mean of the observations. However, the models consistently overestimate woody NPP and poorly represent the spatial patterns of both AGB and woody NPP estimated using plot data. In marked contrast to the observations, DGVMs typically show strong positive relationships between woody NPP and AGB. Resolving these differences will require incorporating forest size structure, mechanistic models of stem mortality and variation in functional composition in DGVMs.This paper is a product of the European Union's Seventh Framework Programme AMAZALERT project (282664). The field data used in this study have been generated by the RAINFOR network, which has been supported by a Gordon and Betty Moore Foundation grant, the European Union's Seventh Framework Programme projects 283080, ‘GEOCARBON’; and 282664, ‘AMAZALERT’; ERC grant ‘Tropical Forests in the Changing Earth System’), and Natural Environment Research Council (NERC) Urgency, Consortium and Standard Grants ‘AMAZONICA’ (NE/F005806/1), ‘TROBIT’ (NE/D005590/1) and ‘Niche Evolution of South American Trees’ (NE/I028122/1). Additional data were included from the Tropical Ecology Assessment and Monitoring (TEAM) Network – a collaboration between Conservation International, the Missouri Botanical Garden, the Smithsonian Institution and the Wildlife Conservation Society, and partly funded by these institutions, the Gordon and Betty Moore Foundation, and other donors. Fieldwork was also partially supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico of Brazil (CNPq), project Programa de Pesquisas Ecológicas de Longa Duração (PELD-403725/2012-7). A.R. acknowledges funding from the Helmholtz Alliance ‘Remote Sensing and Earth System Dynamics’; L.P., M.P.C. E.A. and M.T. are partially funded by the EU FP7 project ‘ROBIN’ (283093), with co-funding for E.A. from the Dutch Ministry of Economic Affairs (KB-14-003-030); B.C. [was supported in part by the US DOE (BER) NGEE-Tropics project (subcontract to LANL). O.L.P. is supported by an ERC Advanced Grant and is a Royal Society-Wolfson Research Merit Award holder. P.M. acknowledges support from ARC grant FT110100457 and NERC grants NE/J011002/1, and T.R.B. acknowledges support from a Leverhulme Trust Research Fellowship

Hyperdominance in Amazonian Forest Carbon Cycling

While Amazonian forests are extraordinarily diverse, the abundance of trees is skewed strongly towards relatively few ‘hyperdominant’ species. In addition to their diversity, Amazonian trees are a key component of the global carbon cycle, assimilating and storing more carbon than any other ecosystem on Earth. Here we ask, using a unique data set of 530 forest plots, if the functions of storing and producing woody carbon are concentrated in a small number of tree species, whether the most abundant species also dominate carbon cycling, and whether dominant species are characterized by specific functional traits. We find that dominance of forest function is even more concentrated in a few species than is dominance of tree abundance, with only ≈1% of Amazon tree species responsible for 50% of carbon storage and productivity. Although those species that contribute most to biomass and productivity are often abundant, species maximum size is also influential, while the identity and ranking of dominant species varies by function and by region

Local hydrological conditions influence tree diversity and composition across the Amazon basin

Tree diversity and composition in Amazonia are known to be strongly determined by the water supplied by precipitation. Nevertheless, within the same climatic regime, water availability is modulated by local topography and soil characteristics (hereafter referred to as local hydrological conditions), varying from saturated and poorly drained to well-drained and potentially dry areas. While these conditions may be expected to influence species distribution, the impacts of local hydrological conditions on tree diversity and composition remain poorly understood at the whole Amazon basin scale. Using a dataset of 443 1-ha non-flooded forest plots distributed across the basin, we investigate how local hydrological conditions influence 1) tree alpha diversity, 2) the community-weighted wood density mean (CWM-wd) – a proxy for hydraulic resistance and 3) tree species composition. We find that the effect of local hydrological conditions on tree diversity depends on climate, being more evident in wetter forests, where diversity increases towards locations with well-drained soils. CWM-wd increased towards better drained soils in Southern and Western Amazonia. Tree species composition changed along local soil hydrological gradients in Central-Eastern, Western and Southern Amazonia, and those changes were correlated with changes in the mean wood density of plots. Our results suggest that local hydrological gradients filter species, influencing the diversity and composition of Amazonian forests. Overall, this study shows that the effect of local hydrological conditions is pervasive, extending over wide Amazonian regions, and reinforces the importance of accounting for local topography and hydrology to better understand the likely response and resilience of forests to increased frequency of extreme climate events and rising temperatures