195 research outputs found

    Assessment of the Biocompatibility of the PLLA-PLCL Scaffold Obtained by Electrospinning

    Get PDF
    AbstractElectrospun membranes of poly (L-Lactide) / poly (L-lactide-co-caprolactone) blend were produced and evaluated by physical and mechanical tests to use as a scaffold for cell growth. The membranes were seeded with endothelial cells (HUVEC) and after culturing time it was visualized by confocal laser scanning microscopy and scanning electron microscopy. The results indicate that the process parameters were capable of producing PLLA-PLCL membranes presenting fibers with diameters in the nanometer range. The scaffolds supported cell attachment and growth, indicating the feasibility of producing scaffolds by electrospinning technique, which could be used in tissue engineering applications

    Comportamiento ecológico ciudadano: un análisis crítico desde la corriente del pensamiento ambiental latinoamericano

    Get PDF
    El objetivo del artículo es realizar una valoración crítica del comportamiento ecológico del ciudadano latinoamericano a partir de la influencia de las corrientes filosóficas del pensamiento ambiental en la región, para ello, se usó como metodología el análisis hermenéutico de obras de grandes pensadores de la región, como Boff (1997, 2012, 2015), Maya (2003, 2008), Rozzi (2001, 2007, 2012), Leff (2010, 2011, 2020), entre otros. Se pudo determinar que la conducta ecológica ciudadana ha estado regida por las directrices del sistema político imperante, basado en el principio único de explotación de recursos naturales para obtener beneficios económicos, dejando de un lado el pensamiento ecocéntrico, se espera, que el reciente acuerdo de Escazú y la influencia ejercida de pensadores ecológicos modele el comportamiento social, partiendo de la democratización de la información ambiental, creación de bases jurídicas sostenibles y la participación organizada del ciudadano.Campus Lima Centr

    Using a risk assessment framework to spatially and temporally spread the fishery catch limit for Antarctic krill in the west Antarctic Peninsula: A template for krill fisheries elsewhere

    Get PDF
    The west Antarctic Peninsula is an important breeding and foraging location for marine predators that consume Antarctic Krill (Euphasia superba). It is also an important focus for the commercial fishery for Antarctic krill, managed by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR). Aiming to minimise ecosystem risks from fishing, whilst enabling a sustainable fishery, CCAMLR has recently endorsed a new management framework that incorporates information about krill biomass estimates, sustainable harvest rates and a risk assessment to spatially and temporally distribute catch limits. We have applied a risk assessment framework to the west Antarctic Peninsula region (Subarea 48.1), with the aim of identifying the most appropriate management units by which to spatially and temporally distribute the local catch limit. We use the best data currently available for implementing the approach, recognising the framework is flexible and can accommodate new data, when available, to improve future estimates of risk. We evaluated 36 catch distribution scenarios for managing the fishery and provide advice about the scale at which the krill fishery can be managed. We show that the spatial distribution with which the fishery currently operates presents some of the highest risks of all scenarios evaluated. We highlight important issues that should be resolved. We emphasize that for the risk assessment to provide robust estimates of risk, it is important that the management units are at a similar scale to ecosystem function. Managing the fishery at small scales has the lowest risk but may necessitate a high level of management interaction. Our results offer advice to CCAMLR about near-term management and could provide a template for the rest of the southwest Atlantic (Area 48), or fisheries elsewhere. As each data layer influences the outcome of the risk assessment, we recommend that updated estimates of the distribution, abundance and consumption of krill, and estimates of available krill biomass will be key as CCAMLR moves forward to develop a longer-term management strategy. Finally, we highlight that the endeavours reported here are the result of a community effort, demonstrating the value of common enterprise

    Time-dependent Stochastic Modeling of Solar Active Region Energy

    Full text link
    A time-dependent model for the energy of a flaring solar active region is presented based on a stochastic jump-transition model (Wheatland and Glukhov 1998; Wheatland 2008; Wheatland 2009). The magnetic free energy of the model active region varies in time due to a prescribed (deterministic) rate of energy input and prescribed (random) flare jumps downwards in energy. The model has been shown to reproduce observed flare statistics, for specific time-independent choices for the energy input and flare transition rates. However, many solar active regions exhibit time variation in flare productivity, as exemplified by NOAA active region AR 11029 (Wheatland 2010). In this case a time-dependent model is needed. Time variation is incorporated for two cases: 1. a step change in the rates of flare jumps; and 2. a step change in the rate of energy supply to the system. Analytic arguments are presented describing the qualitative behavior of the system in the two cases. In each case the system adjusts by shifting to a new stationary state over a relaxation time which is estimated analytically. The new model retains flare-like event statistics. In each case the frequency-energy distribution is a power law for flare energies less than a time-dependent rollover set by the largest energy the system is likely to attain at a given time. For Case 1, the model exhibits a double exponential waiting-time distribution, corresponding to flaring at a constant mean rate during two intervals (before and after the step change), if the average energy of the system is large. For Case 2 the waiting-time distribution is a simple exponential, again provided the average energy of the system is large. Monte Carlo simulations of Case~1 are presented which confirm the analytic estimates. The simulation results provide a qualitative model for observed flare statistics in active region AR 11029.Comment: 25 pages, 9 figure

    Indications for cardiovascular magnetic resonance in children with congenital and acquired heart disease: an expert consensus paper of the Imaging Working Group of the AEPC and the Cardiovascular Magnetic Resonance Section of the EACVI

    Get PDF
    This article provides expert opinion on the use of cardiovascular magnetic resonance (CMR) in young patients with congenital heart disease (CHD) and in specific clinical situations. As peculiar challenges apply to imaging children, paediatric aspects are repeatedly discussed. The first section of the paper addresses settings and techniques, including the basic sequences used in paediatric CMR, safety, and sedation. In the second section, the indication, application, and clinical relevance of CMR in the most frequent CHD are discussed in detail. In the current era of multimodality imaging, the strengths of CMR are compared with other imaging modalities. At the end of each chapter, a brief summary with expert consensus key points is provided. The recommendations provided are strongly clinically oriented. The paper addresses not only imagers performing CMR, but also clinical cardiologists who want to know which information can be obtained by CMR and how to integrate it in clinical decision-makin

    Using seabird and whale distribution models to estimate spatial consumption of krill to inform fishery management

    Get PDF
    Ecosystem dynamics at the northwest Antarctic Peninsula are driven by interactions between physical and biological processes. For example, baleen whale populations are recovering from commercial harvesting against the backdrop of rapid climate change, including reduced sea ice extent and changing ecosystem composition. Concurrently, the commercial harvesting of Antarctic krill is increasing, with the potential to increase the likelihood for competition with and between krill predators and the fishery. However, understanding the ecology, abundance, and spatial distribution of krill predators is often limited, outdated, or at spatial scales that do not match those desired for effective fisheries management. We update current knowledge of predator dependence on krill by integrating telemetry-based data, at-sea observational surveys, estimates of predator abundance, and physiological data to estimate the spatial distribution of krill consumption during the austral summer by three species of Pygoscelis penguin, 11 species of flying seabirds, one species of pinniped, and two species of baleen whale. Our models show that the majority of important areas for krill predator foraging are close to penguin breeding colonies in nearshore areas where humpback whales also regularly feed, and along the shelf-break, though we caution that not all known krill predators are included in these analyses. We show that krill consumption is highly variable across the region, and often concentrated at fine spatial scales, emphasizing the need for the management of the local krill fishery at relevant temporal and spatial scales. We also note that krill consumption by recovering populations of krill predators provides further evidence in support of the krill surplus hypothesis, and highlight that despite less than comprehensive data, cetaceans are likely to consume a significant proportion of the krill consumed by natural predators but are not currently considered directly in the management of the krill fishery. If management of the krill fishery is to be precautionary and operate in a way that minimizes the risks to krill predator populations, it will be necessary in future analyses, to include up-to-date and precise abundance and consumption estimates for pack-ice seals, finfish, squid, and other baleen whale species not currently considered

    Mediators of lifestyle behaviour changes in obese pregnant women. Secondary analyses from the DALI lifestyle randomised controlled trial

    Get PDF
    Altres ajuts: The project described has received funding from the European Community's 7th Framework Programme (FP7/2007-2013) under grant agreement no. 242187. In the Netherlands, additional funding was provided by the Netherlands Organization for Health Research and Development (ZonMw) (grant no. 200310013). In Poland, additional funding was obtained from Polish Ministry of Science (grant no. 2203/7. PR/2011/2). In Denmark, additional funding was provided by the Odense University Free Research Fund. In the United Kingdom, the DALI team acknowledge the support received from the NIHR Clinical Research Network: Eastern, especially the local diabetes clinical and research teams based in Cambridge. In Spain, additional funding was provided by CAIBER 1527-B-226. The funders had no role in any aspect of the study beyond funding.A better understanding of what drives behaviour change in obese pregnant overweight women is needed to improve the effectiveness of lifestyle interventions in this group at risk for gestational diabetes (GDM). Therefore, we assessed which factors mediated behaviour change in the Vitamin D and Lifestyle Intervention for GDM Prevention (DALI) Lifestyle Study. A total of 436 women, with pre-pregnancy body mass index ≥29 kg/m , ≤19 + 6 weeks of gestation and without GDM, were randomised for counselling based on motivational interviewing (MI) on healthy eating and physical activity, healthy eating alone, physical activity alone, or to a usual care group. Lifestyle was measured at baseline, and at 24-28 and 35-37 weeks of gestation. Outcome expectancy, risk perception, task self-efficacy and social support were measured at those same time points and considered as possible mediators of intervention effects on lifestyle. All three interventions resulted in increased positive outcome expectancy for GDM reduction, perceived risk to the baby and increased task self-efficacy. The latter mediated intervention effects on physical activity and reduced sugared drink consumption. In conclusion, our MI intervention was successful in increasing task self-efficacy, which was related to improved health behaviours

    A reduction in sedentary behaviour in obese women during pregnancy reduces neonatal adiposity : the DALI randomised controlled trial

    Get PDF
    Altres ajuts: Funding The project described has received funding from the European Community's 7th Framework Programme (FP7/2007-2013) under grant agreement no. 242187. In the Netherlands, additional funding was provided by the Netherlands Organisation for Health Research and Development (ZonMw) (grant no. 200310013). In Poland, additional funding was obtained from the Polish Ministry of Science (grant no. 2203/7, PR/2011/2). In Denmark, additional funding was provided by Odense University Free Research Fund. In the UK, the DALI team acknowledges the support received from the National Institute for Health Research Clinical Research Network Eastern, especially the local diabetes clinical and research teams based in Cambridge. In Spain, additional funding was provided by CAIBER (Consorcio de Apoyo a la Investigación Biomédica en Red; 1527-B-226). The funders had no role in any aspect of the study beyond funding.Aims/hypothesis: Offspring of obese women are at increased risk of features of the metabolic syndrome, including obesity and diabetes. Lifestyle intervention in pregnancy might reduce adverse effects of maternal obesity on neonatal adiposity. Methods: In the Vitamin D And Lifestyle Intervention for Gestational Diabetes Mellitus (GDM) Prevention (DALI) lifestyle trial, 436 women with a BMI ≥29 kg/m were randomly assigned to counselling on healthy eating (HE), physical activity (PA) or HE&PA, or to usual care (UC). In secondary analyses of the lifestyle trial, intervention effects on neonatal outcomes (head, abdominal, arm and leg circumferences and skinfold thicknesses, estimated fat mass, fat percentage, fat-free mass and cord blood leptin) were assessed using multilevel regression analyses. Mediation of intervention effects by lifestyle and gestational weight gain was assessed. Results: Outcomes were available from 334 neonates. A reduction in sum of skinfolds (−1.8 mm; 95% CI −3.5, −0.2; p = 0.03), fat mass (−63 g; 95% CI −124, −2; p = 0.04), fat percentage (−1.2%; 95% CI −2.4%, −0.04%; p = 0.04) and leptin (−3.80 μg/l; 95% CI −7.15, −0.45; p = 0.03) was found in the HE&PA group, and reduced leptin in female neonates in the PA group (−5.79 μg/l; 95% CI −11.43, −0.14; p = 0.05) compared with UC. Reduced sedentary time, but not gestational weight gain, mediated intervention effects on leptin in both the HE&PA and PA groups. Conclusions/interpretation: The HE&PA intervention resulted in reduced adiposity in neonates. Reduced sedentary time seemed to drive the intervention effect on cord blood leptin. Implications for future adiposity and diabetes risk of the offspring need to be elucidated. Trial registration: ISRCTN70595832
    corecore