1,598 research outputs found

    Rethinking paradigms for studying mechanisms of action of plant bioactives

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    Many foods in our diets such as berries, tea, chocolate and wine contain flavonoids, which are natural components of plants. A substantial body of evidence supports the role of flavonoids in providing protection against cardio-metabolic diseases and disorders. Despite the nearly exponential growth in flavonoid research in the past 20 years, limited progress has been made in understanding how these dietary components work. Research initially focused on their antioxidant activity without taking into account their metabolism, which now appears extensive. This has provided a new research impetus to understand the biological activity of the flavonoid metabolites. Here, we outline recent research, which suggests a highly complex interplay between metabolism, intestinal microflora, the immune system and various tissues of our body

    Influence of Current Pulse Shape on Directly Modulated Systems Performance in Metro Area Optical Networks

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    Due to the fact that a metro network market is very cost sensitive, direct modulated schemes appear attractive. In this paper a CWDM (Coarse Wavelength Division Multiplexing) system is studied in detail by means of an Optical Communication System Design Software; a detailed study of the modulated current shape (exponential, sine and gaussian) for 2.5 Gb/s CWDM Metropolitan Area Networks is performed to evaluate its tolerance to linear impairments such as signal-to-noise-ratio degradation and dispersion. Point-to-point links are investigated and optimum design parameters are obtained. Through extensive sets of simulation results, it is shown that some of these shape pulses are more tolerant to dispersion when compared with conventional gaussian shape pulses. In order to achieve a low Bit Error Rate (BER), different types of optical transmitters are considered including strongly adiabatic and transient chirp dominated Directly Modulated Lasers (DMLs). We have used fibers with different dispersion characteristics, showing that the system performance depends, strongly, on the chosen DML?fiber couple

    Niños pantalla: lenguaje y comunicación

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    En la actualidad, los niños crecen en una sociedad tecnológica y conviven diariamente con las TIC’s(tecnologías de la información y la comunicación). Tanto los padres como los menores se ven envueltos en un contexto social digitalizado. El objetivo de este trabajo es analizar la influencia de las tecnologías en las habilidades comunicativas en la primera infancia. Se realiza una revisión bibliográfica con el fin de conocer las consecuencias positivas y negativas de su uso en una edad temprana. En este sentido, las tecnologías les ayudan a comunicarse y a desarrollarse en un entono digital. Por el contrario, la sobreexposición a las mismas puede provocar trastornos en el sueño y trastornos en el lenguaje y la comunicación. Los padres deben orientar a sus hijos en la gestión del tiempo de uso de las tecnologías y apoyarse en profesionales (maestros, logopedas, psicólogos…) que les ayuden a establecer pautas y horarios.At present, children grow up in a technological society and live with ICTs (information and communication technologies) on a daily basis. Both parents and minors are involved in a digitized social context. The objective of this work is to analyze the influence of technologies on communication skills in early childhood. A bibliographic review is carried out in order to know the positive and negative consequences of its use at an early age. In this sense, technologies help them to communicate and develop in a digital environment. On the contrary, overexposure to them can cause sleep disorders and language and communication disorders. Parents should guide their children in managing the time to use technology and rely on professionals (teachers, speech therapists, psychologists ...) to help them establish guidelines and schedules

    Upscaling agroforestry in the tropics through actor-networks: a comparative case study of cacao farming systems in two regions of Colombia

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    Agroforestry systems (AFS) upscaling has the potential to integrate sustainability and resilience objectives into agriculture. However, this is a daunting task requiring multi-actor collaboration across public and private sectors at multiple governance levels, coupled with innovative approaches to jointly managing AFS knowledge. Understanding such multi-actor interactions from a network perspective may help to unravel how social structures, created by relational patterns enhance or hinder AFS upscaling. Our paper aims to comparatively explore the role of regional actor-networks on AFS upscaling for a selected farming system. By conducting semi-structured interviews, we collected information about the ties of 86 actors supporting cacao agroforestry systems (CAFS) across two regions of Colombia. We use social network analysis (SNA) to comparatively visualize and understand the general structure of these networks, find relational patterns between the diverse categories of actors involved, and identify a set of key players bridging the majority of the actors within these networks. We find highly centralized networks that connect multiple actors by a low number of mostly non-reciprocal ties. Within these networks, we identify a predominance of bridging ties over bonding ties, homophily patterns among research and education institutions, and heterophily configurations among farmer-based organizations. We also find that the composition of the sets of key actors and the platforms where they converge varies substantially from region to region due to decentralized agricultural policies and differing characteristics across regions. Our approach provides key entry points for promoting multi-actor coalitions that can effectively expand the benefits of AFS in tropical agricultural systems

    Analyzing influencing factors to scale up agroforestry systems in Colombia: A comparative ex-ante assessment of cacao farming and cattle ranching in two regions

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    Agroforestry systems (AFS) are proved to enhance sustainable land management. Thus, there is increasing demand for effective ways to scale up AFS so that more people can benefit. Consequently, this study assesses the scaling-up potential of agroforestry systems (AFS) using cacao farming and cattle ranching in Caqueta and Cesar, Colombia, as examples. An ex-ante assessment using the ScalA tool is conducted through interviews with AFS experts from institutions promoting AFS. Using a comparative approach, results reveal that AFS have different scaling-up potential depending on the type of farming system and location characteristics. In our case, it is slightly higher for cacao farming than for cattle ranching in both regions and it is higher in Caqueta than in Cesar for both systems. Factors hindering the scaling-up potential for both regions are economic conditions at the local and regional levels since there is a lack of stable and differentiated markets to absorb AFS products. In contrast, the scaling-up potential in both regions is increased by the factors related to the capacity of the organizations that promote AFS and the attitudes of local communities toward them. The study generates information about factors that may hinder or foster AFS scaling-up, including not just the capacities and mechanisms to promote them but also the enabling conditions. This contributes to prioritizing AFS interventions and better allocating their resources to increase their chances of successful scaling-up

    Microglial regulation of satiety and cognition

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    Microglia have been known for decades as key immune cells that shape the central nervous system (CNS) during development and respond to brain pathogens and injury in adult life. Recent findings now suggest that these cells also play a highly complex role in several other functions of the CNS. In this review, we provide a brief overview of the established microglial functions in development and disease. We also discuss emerging research suggesting that microglia are important for both cognitive function and the regulation of food intake. With respect to cognitive function, current data suggest microglia are not indispensable for neurogenesis, synaptogenesis or cognition in the healthy young adult, although they crucially modulate and support these functions. In doing so, they are likely important in supporting the balance between apoptosis and survival of newborn neurones and in orchestrating appropriate synaptic remodelling in response to a learning stimulus. We also explore the possibility of a role for microglia in feeding and satiety. Microglia have been implicated in both appetite suppression with sickness and obesity and in promoting feeding under some conditions and we discuss these findings here, highlighting the contribution of these cells to healthy brain function

    Microwave-assisted extraction of hemicellulosic oligosaccharides and phenolics from Robinia pseudoacacia wood

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    Financiaciado para publicación en acceso aberto: Universidade de Vigo/CISUGMicrowave-assisted autohydrolysis is an environmentally friendly intensification technology that permits the selective solubilization of hemicelluloses in form of oligosaccharides in a short time and with low energy consumption. The purpose of this work was to evaluate the suitability of microwave-assisted autohydrolysis to produce oligosaccharides and phenolics with potential prebiotic and antioxidant activities from Robinia pseudoacacia wood. The influence of treatment time (0–30 min) and temperature (200–230 ◦C) on oligosaccharide production was studied and conditions of 230 ◦C and 0.25 min resulted in maximum content of xylooligosaccharides (7.69 g XO/L) and more efficient energy consumption. Furthermore, under those conditions, liquors showed high contents of phenols (80.28 mg GAE/g of RW) and flavonoids (44.51 RE/g) with significant antioxidant activities (112.07 and 102.30 mg TE/g, measured by ABTS and FRAP tests, respectively). Additionally, the solubilized hemicelluloses were structurally characterized by HPAEC-PAD, MALDI-TOF-MS, FTIR and TGA/DSC, and HPLC-ESI-MS analysis allowed the tentative identification of 17 phytochemicals.Ministerio de Economía y Competitividad | Ref. PID2019-110031RB-I00Xunta de Galicia | Ref. ED431C 2017/62-GRCMinisterio de Ciencia e Innovación | Ref. FPU21/02446Ministerio de Ciencia e Innovación | Ref. PRE 2020 093359Ministerio de Ciencia e Innovación | Ref. RYC2018-026177-IXunta de Galicia | Ref. ED481B-2022-02

    Synergetic effect of hydrothermal and deep eutectic solvents (DES) pretreatments on Robinia wood fractionation for the manufacture of bioethanol and cellulose nanocrystals

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    This study dealt with the use of environmentally friendly processes based on microwave-assisted autohydrolysis (MAA) and deep eutectic solvents (DES) for the selective fractionation of Robinia pseudoacacia wood (RW) within a biorefinery approach. MAA enabled the recovery of 76% of hemicelluloses in the form of oligomers. Afterwards, different conditions were assessed for the optimal delignification of RW with the DES choline chloride combined with lactic acid reaching delignification ratios up to 86%. Two different methods were accomplished to valorize the cellulosic-rich solid fraction after delignification: (i) bioethanol via enzymatic-fermentative pathway (attaining 53.3 g ethanol/L, about 83% of ethanol yield), and (ii) cellulose nanocrystals (length of 27–550 nm, width of 2–12 nm). Hence, this study presents a novel multiproduct biorefinery to selectively separate the main components of RW and valorize its cellulosic fraction using eco-friendly proceduresUniversidade de Vigo/CISUGMinisterio de Economía| Ref. PID2019-110031RB-I00Xunta de Galicia | Ref. ED431C 2017/62-GRCMinisterio de Ciencia, Innovación y Universidades | Ref. FPU21/02446Ministerio de Ciencia, Innovación y Universidades | Ref. PRE2020-093359Ministerio de Ciencia, Innovación y Universidades | Ref. RYC2018-026177-IXunta de Galicia | Ref. ED481B-2022-02

    The Role of Aeroallergen Sensitization Testing in Asthma Management

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    Copyright © 2020 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.Peer reviewedPublisher PD

    Numerical comparison and efficiency analysis of three vertical axis turbine of H-Darrieus type

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    Hydropower is an important source of energy in Latin America. Many countries in the region, including Brazil, Peru, Colombia, and Chile, rely heavily on hydropower plants to meet their energy needs. However, there are also challenges related to the use of hydropower in the region, such as the construction of dams that can have negative impacts on ecosystems and local communities. A new alternative is the production of energy through hydrokinetic turbines because they are a clean and renewable energy source that does not emit greenhouse gases. In addition, its production is predictable and can be generated in a variety of environments, from coasts to rivers and canals. Within the hydrokinetic turbines are the H-Darrieus turbines although they are still under development, they are seen as an important opportunity to diversify the energy matrix and reduce dependence on fossil fuels. The main purpose of this study is to determine and compare the efficiency of three Darrieus H-type vertical axis hydrokinetic turbines numerically. The turbines were configured with different solidities. The NACA 0018 profile was used for the turbine design. The study was carried out using the ANSYS® Fluent 2022R2 software, two-dimensional (2D) simulations set up constant operating conditions. Rotation speed variations have been set between 21 and 74 RPM with 10 rpm increments. Furthermore, the General Richardson extrapolation method is used for the analysis of mesh convergence, monitoring the turbine power coefficient as a convergence parameter. The numerical results show that the turbine H-Darrieus with a solidity of 1.0, a wider operating range, and lower power and torque coefficient. At low TRS, the largest solidity provided the best efficiency and the greatest self-starting capability, but it also had the smallest operating rang
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