138 research outputs found

    Emerging energy sources' social acceptability: Evidence from marine-based energy projects

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    Any decrease in global warming and its effects can only occur with a substantial reduction in anthropogenic CO2 emissions. In this context, renewable energy sources, particularly emerging sources, may play a central role in accelerating the transition from fossil fuels to cleaner energy sources. Emerging energy sources are renewable and have the potential to reduce global warming emissions; however, they are in the early development stages. These technologies include enhanced geothermal processes, artificial photosynthesis, and marine energy. In this study, we assess the main attributes that determine the social acceptance of renewable marine energy projects, highlighting individual preferences and heterogeneity for these projects. The results show that energy generation, ecological impact, job creation, co-ownership, and distributional justice are statistically significant attributes that support projects. However, individual preferences are highly heterogeneous. The existence of distinct classes (two in this case) with different preferences for marine energy attributes indicates that the one-size-fits-all approach may be inappropriate. Instead, policymakers and energy producers should tailor their proposals to meet the needs of both groups, considering their preferences and concerns

    Evaluation of Moringa oleifera and corn starch as feed for seed production of the pearl oyster Pteria sterna (Gould,1851)

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    In the search for complementary diets to improve performance in bivalve farming, the use of terrestrial plants with nutritional and nutraceutical properties has been proposed as an alternative. The effectiveness of moringa leaf meal Moringa oleifera (Mo) was evaluated under controlled laboratory conditions (30 days), as a dietary supplement during the pre-growth stage of Pteria sterna seeds (7.2 ± 0.59 mm), as well as its combinations with microalgae and corn starch (Co), on growth and survival in the laboratory and its subsequent initial suspended culture in the sea. Diets were formulated with a mixture of the microalgae Tetraselmis suecica and Chaetoceros gracilis (M), diet M; M and 5% Mo (M + Mo); diet M and 5% corn starch (M + Co); 100% moringa leaf meal (Mo); 100% corn starch (Co), and diet M with 2.5% Mo and 2,5% Co (M + Mo + Co). The Mo diet did not provide preseed sustainability, resulting in 100% mortality at 30 days. From the rest of the diets, M obtained the lowest oyster survival, while M + Mo and M + Mo + Co showed the highest growth rates. At the end of the laboratory bioassay, the seeds were sown in a culture system in the open sea (50 days), where the highest growth occurred in the juveniles previously fed with M + Mo + Co. The results suggest that, in the nursery, P. sterna pre-seeds can be maintained with a diet of 100% corn starch, but not with 100% moringa flour, probably due to its poor digestibility. However, moringa used as an additive to the microalgae diet provided a higher yield in the oyster, which is reflected in a higher yield in the initial culture outdoors.Universidade de Vigo/CISUGCYTEDUniversidad Técnica de Manabí, Ecuador | Ref. PYTBEC408-2018-FCV001

    Spatial and temporal shift in the factors affecting the population dynamics of Calanus copepods in the North Sea.

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    The swap in abundance between two Calanus species in the North Sea during the 1980s constitutes a quintessential example of regime shift, with important ecosystemic and economic repercussions because these copepods constitute a major component of the diet of larval and juvenile cods. It is hypothesized that this transition was driven by gradual changes in primary productivity, the North Atlantic Oscillation (NAO) and sea surface temperatures (SST), and yet how these factors contribute to the population dynamics of these two species and the overall regime shift remains unclear. Here, we combine a highly resolved and spatially structured longitudinal dataset with population dynamics theory-based models to obtain a thorough and more detailed description of populations’ responses to the regime shift observed in the North Sea. Our analyses highlight that this transition exhibits a clear spatial structure and involved a decoupling between the dynamics of Calanus finmarchicus and the NAO in western regions and between Calanus helgolandicus and SST in the eastern regions of the North Sea. Consequently, the observed switch in abundance between these species reflects the interaction between species-specific attributes, a well-defined spatial structure with a marked east–west axis and a decoupling between the ecological drivers and Calanus population dynamics following the shift. Succinctly, we suspect that higher water temperatures have favored C. helgolandicus and resulted in restrictive conditions for C. finmarchicus, eventually overshadowing the effects of NAO detected in historical records. Overall, our study illustrates how population dynamics theory can be successfully employed to disentangle the complex and multifactorial nature of a regime shift in response to gradually changing environmental conditions

    GRB 091127: The cooling break race on magnetic fuel

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    Using high-quality, broad-band afterglow data for GRB 091127, we investigate the validity of the synchrotron fireball model for gamma-ray bursts, and infer physical parameters of the ultra-relativistic outflow. We used multi-wavelength follow-up observations obtained with GROND and the XRT onboard the Swift satellite. The resulting afterglow light curve is of excellent accuracy, and the spectral energy distribution is well-sampled over 5 decades in energy. These data present one of the most comprehensive observing campaigns for a single GRB afterglow and allow us to test several proposed emission models and outflow characteristics in unprecedented detail. Both the multi-color light curve and the broad-band SED of the afterglow of GRB 091127 show evidence of a cooling break moving from high to lower energies. The early light curve is well described by a broken power-law, where the initial decay in the optical/NIR wavelength range is considerably flatter than at X-rays. Detailed fitting of the time-resolved SED shows that the break is very smooth with a sharpness index of 2.2 +- 0.2, and evolves towards lower frequencies as a power-law with index -1.23 +- 0.06. These are the first accurate and contemporaneous measurements of both the sharpness of the spectral break and its time evolution. The measured evolution of the cooling break (nu_c propto t^-1.2) is not consistent with the predictions of the standard model, wherein nu_c propto t^-0.5 is expected. A possible explanation for the observed behavior is a time dependence of the microphysical parameters, in particular the fraction of the total energy in the magnetic field epsilon_B. This conclusion provides further evidence that the standard fireball model is too simplistic, and time-dependent micro-physical parameters may be required to model the growing number of well-sampled afterglow light curves.Comment: accepted to A&A, 13 pages, 5 figure

    Prótesis 3D para corregir eje corporal y equilibro en lechuza de campanario y cernícalo americano

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    The amputation of a pelvic limb in raptor, must be carefully evaluated and taken as the last possibility to save the life of the bird, because after the amputation, several degenerative factors can occur, such as alteration of the body axis, an incorrect distribution of weight and bumblefoot. A good alternative to counteract these problems is the use of prostheses that seek to help recover the body axis and maintain good posture. The use of 3D printers for this type of project offers a more accessible and easier to work alternative due to its versatility in both design and materials. The present project tests the design of a 3D prosthesis and documents the correction of the body axis and the modification of its use in the daily activities of an american kestrel and a barn owl with a tibiotarsal amputation in its distal third. Although the use of prostheses does not allow the reintroduction of the birds, it gives the opportunity to integrate them into conservation programs such as captivity reproduction or environmental education.La amputación de miembros pélvicos en aves rapaces, debe ser evaluada con detenimiento y considerada como el último recurso para salvar la vida del ave, debido a que posterior a la amputación, pueden derivarse una serie de factores degenerativos, como la alteración de eje corporal, distribución inadecuada del peso corporal y pododermatitis. Una buena alternativa para contrarrestar estos problemas, es el uso de prótesis, que busquen recuperar el eje corporal y mantener una buena postura en el ave. El uso de impresoras 3D para este tipo de proyectos, ofrece una alternativa más accesible y sencilla debido a su versatilidad tanto en diseño como en materiales. El presente proyecto pone a prueba el diseño de una prótesis 3D y documenta la corrección de eje corporal e incorporación de la prótesis en las actividades diarias de un cernícalo americano (Falco sparverius) y una lechuza de campanario (Tyto alba), ambas con una amputación tibiotarsal en su tercio distal. A pesar de que la utilización de prótesis no permite la reintroducción de las aves al medio ambiente, ofrece una oportunidad para integrar dichas aves en programas de conservación, tales como reproducción en cautiverio o educación ambiental

    Visual Encoding of Social Cues Contributes to Moral Reasoning in Autism Spectrum Disorder: An Eye-Tracking Study

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    Eye-tracking studies suggest that visual encoding is important for social processes such as socio-moral reasoning. Alterations to the visual encoding of faces, for example, have been linked to the social phenotype of autism spectrum disorders (ASDs) and are associated with social and communication impairments. Yet, people with ASD often perform similarly to neurotypical participants on measures of moral reasoning, supporting the hypothesis of differential mechanisms of moral reasoning in ASD. The objective of this study was to document visual encoding and moral reasoning in ASD and neurotypical individuals using a visual, ecological, sociomoral reasoning paradigm paired with eye-tracking. Two groups (ASD, Control) matched for age and IQ completed the SoMoral task, a set of picture situations describing everyday moral dilemmas, while their eye movements and pupil dilation were recorded. Moral understanding, decision-making, and justification were recorded. Participants with ASD presented a longer time to first fixation on faces. They also understood fewer dilemmas and produced fewer socially adaptive responses. Despite a similar average level of moral maturity, the justifications produced by participants with ASD were not distributed in the same way as the neurotypical participants. Visual encoding was a significant predictor of moral decision-making and moral justification for both groups. The results are discussed in the context of alternative mechanisms of moral reasoning in ASD

    Ecology of the collapse of Rapa Nui society

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    Collapses of food producer societies are recurrent events in prehistory and have triggered a growing concern for identifying the underlying causes of convergences/divergences across cultures around the world. One of the most studied and used as a paradigmatic case is the population collapse of the Rapa Nui society. Here, we test different hypotheses about it by developing explicit population dynamic models that integrate feedbacks between climatic, demographic and ecological factors that underpinned the sociocultural trajectory of these people. We evaluate our model outputs against a reconstruction of past population size based on archaeological radiocarbon dates from the island. The resulting estimated demographic declines of the Rapa Nui people are linked to the long-term effects of climate change on the island's carrying capacity and, in turn, on the 'per-capita food supply'

    Spatio-temporal assessment of beech growth in relation to climate extremes in Slovenia – An integrated approach using remote sensing and tree-ring data

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    Climate change is predicted to affect tree growth due to increased frequency and intensity of extreme events such as ice storms, droughts and heatwaves. Yet, there is still a lot of uncertainty on how trees respond to an increase in frequency of extreme events. Use of both ground-based wood increment (i.e. ring width) and remotely sensed data (i.e. vegetation indices) can be used to scale-up ground measurements, where there is a link between the two, but this has only been demonstrated in a few studies. We used tree-ring data together with crown features derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) to assess the effect of extreme climate events on the growth of beech (Fagus sylvatica L.) in Slovenia. We found evidence that years with climate extremes during the growing season (drought, high temperatures) had a lower ring width index (RWI) but we could not find such evidence for the remotely sensed EVI (Enhanced Vegetation Index). However, when assessing specific events where leaf burning or wilting has been reported (e.g. August 2011) we did see large EVI anomalies. This implies that the impact of drought or heatwave events cannot be captured by EVI anomalies until physical damage on the canopy is caused. This also means that upscaling the effect of climate extremes on RWI by using EVI anomalies is not straightforward. An exception is the 2014 ice storm that caused a large decline in both RWI and EVI. Extreme climatic parameters explained just a small part of the variation in both RWI and EVI by, which could indicate an effect of other climate variables (e.g. late frost) or biotic stressors such as insect outbreaks. Furthermore, we found that RWI was lower in the year after a climate extreme occurred in the late summer. Most likely due to the gradual increase in temperature and more frequent drought we found negative trends in RWI and EVI. EVI maps could indicate where beech is sensitive to climate changes and could be used for planning mitigation interventions. Logical next steps should focus on a tree-based understanding of the short -and long-term effects of climate extremes on tree growth and survival, taking into account differential carbon allocation to the crown (EVI) and to wood-based variables. This research highlights the value of an integrated approach for upscaling tree-based knowledge to the forest level

    ¿Las lechuzas de campanario (Tyto alba) son estrictamente nocturnas? Cuidado parental de una hembra en cautiverio.

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    Se describen las actividades diurnas y nocturnas de una hembra de lechuza de campanario en cautiverio, con énfasis en la asignación de tiempo a sus actividades diurnas y nocturnas. Las observaciones se realizaron mediante la vídeo-grabación y posterior revisión de sus actividades al interior de una caja nido. La hembra presentó un patrón de actividades diurnas. Se discute el papel de disponibilidad de alimento y el número de polluelos producidos en este patrón

    Reactivation of Fault Systems by Compartmentalized Hydrothermal Fluids in the Southern Andes Revealed by Magnetotelluric and Seismic Data

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    In active volcanic arcs such as the Andean volcanic mountain belt, magmatically‐sourced fluids are channelled through the brittle crust by faults and fracture networks. In the Andes, volcanoes, geothermal springs and major mineral deposits have a spatial and genetic relationship with NNE‐trending, margin‐parallel faults and margin‐oblique, NW‐trending Andean Transverse Faults (ATF). The Tinguiririca and Planchón‐Peteroa volcanoes in the Andean Southern Volcanic Zone (SVZ) demonstrate this relationship, as their spatially associated thermal springs show strike alignment to the NNE‐oriented El Fierro Thrust Fault System. We constrain the fault system architecture and its interaction with volcanically sourced hydrothermal fluids using a combined magnetotelluric (MT) and seismic survey that was deployed for 20 months. High conductivity zones are located along the axis of the active volcanic chain, delineating fluids and/or melt. A distinct WNW‐trending cluster of seismicity correlates with resistivity contrasts, considered to be a reactivated ATF. Seismicity occurs below 4 km, suggesting activity is limited to basement rocks, and the cessation of seismicity at 9 km delineates the local brittle‐ductile transition. As seismicity is not seen west of the El Fierro fault, we hypothesize that this structure plays a key role in compartmentalizing magmatically‐derived hydrothermal fluids to the east, where the fault zone acts as a barrier to cross‐fault fluid migration and channels fault‐parallel fluid flow to the surface from depth. Increases in fluid pressure above hydrostatic may facilitate reactivation. This site‐specific case study provides the first three‐dimensional seismic and magnetotelluric observations of the mechanics behind the reactivation of an ATF
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