168 research outputs found
Ecological Diversity within Rear-Edge: A Case Study from Mediterranean Quercus pyrenaica Willd
Understanding the ecology of populations located in the rear edge of their distribution is
key to assessing the response of the species to changing environmental conditions. Here, we focus on
rear-edge populations of Quercus pyrenaica in Sierra Nevada (southern Iberian Peninsula) to analyze
their ecological and floristic diversity. We perform multivariate analyses using high-resolution
environmental information and forest inventories to determine how environmental variables differ
among oak populations, and to identify population groups based on environmental and floristic
composition. We find that water availability is a key variable in explaining the distribution of
Q. pyrenaica and the floristic diversity of their accompanying communities within its rear edge.
Three cluster of oak populations were identified based on environmental variables. We found
differences among these clusters regarding plant diversity, but not for forest attributes. A remarkable
match between the populations clustering derived from analysis of environmental variables and
the ordination of the populations according to species composition was found. The diversity of
ecological behaviors for Q. pyrenaica populations in this rear edge are consistent with the high genetic
diversity shown by populations of this oak in the Sierra Nevada. The identification of differences
between oak populations within the rear-edge with respect to environmental variables can aid with
planning the forest management and restoration actions, particularly considering the importance of
some environmental factors in key ecological aspects.LIFE-ADAPTAMED: Protection of key ecosystem services by adaptive management of Climate Change endangered Mediterranean socioecosystems
LIFE14 CCA/ES/000612H2020 project European Long-Term Ecosystem and socio-ecological Research Infrastructure (eLTER)European Research Council (ERC)
64703
Modeling Major Rural Land-Use Changes Using the GIS-Based Cellular Automata Metronamica Model: The Case of Andalusia (Southern Spain)
The effective and efficient planning of rural land-use changes and their impact on the environment is critical for land-use managers. Many land-use growth models have been proposed for forecasting growth patterns in the last few years. In this work; a cellular automata (CA)-based land-use model (Metronamica) was tested to simulate (1999–2007) and predict (2007–2035) land-use dynamics and land-use changes in Andalucía (Spain). The model was calibrated using temporal changes in land-use covers and was evaluated by the Kappa index. GIS-based maps were generated to study major rural land-use changes (agriculture and forests). The change matrix for 1999–2007 showed an overall area change of 674971 ha. The dominant land uses in 2007 were shrubs (30.7%), woody crops on dry land (17.3%), and herbaceous crops on dry land (12.7%). The comparison between the reference and the simulated land-use maps of 2007 showed a Kappa index of 0.91. The land-cover map for the projected PRELUDE scenarios provided the land-cover characteristics of 2035 in Andalusia; developed within the Metronamica model scenarios (Great Escape; Evolved Society; Clustered Network; Lettuce Surprise U; and Big Crisis). The greatest differences were found between Great Escape and Clustered Network and Lettuce Surprise U. The observed trend (1999–2007–2035) showed the greatest similarity with the Big Crisis scenario. Land-use projections facilitate the understanding of the future dynamics of land-use change in rural areas; and hence the development of more appropriate plans and policies
Documenting models and workflows: the next challenge in the field of ecological data management
Los modelos ecológicos se han convertido en una pieza clave de esta ciencia. La generación de conocimiento se consigue en buena medida mediante procesos analíticos más o menos complejos aplicados sobre conjuntos de datos diversos. Pero buena parte del conocimiento necesario para diseñar e implementar esos modelos no está accesible a la comunidad científica. Proponemos la creación de herramientas informáticas para documentar, almacenar y ejecutar modelos ecológicos y flujos de trabajo. Estas herramientas (repositorios de modelos) están siendo desarrolladas por otras disciplinas como la biología molecular o las ciencias de la Tierra. Presentamos un repositorio de modelos (ModeleR) desarrollado en el contexto del Observatorio de seguimiento del cambio global de Sierra Nevada (Granada-Almería). Creemos que los repositorios de modelos fomentarán la cooperación entre científicos, mejorando la creación de conocimiento relevante que podría ser transferido a los tomadores de decisiones.Ecological models have become a key part of this scientific discipline. Most of the knowledge created by ecologists is obtained by applying analytical processes to primary data. But most of the information underlying how to create models or use analytic techniques already published in the scientific literature is not readily available to scientists. We are proposing the creation of computer tools that help to document, store and execute ecological models and scientific workflows. These tools (called model repositories) are being developed by other disciplines such as molecular biology and earth science. We are presenting a model repository (called ModeleR) that has been developed in the context of the Sierra Nevada Global Change Observatory (Granada-Almería. Spain). We believe that model repositories will foster cooperation among scientists, enhancing the creation of relevant knowledge that could be transferred to environmental managers.El desarrollo de ModeleR ha sido financiado por la Consejería de Medio Ambiente y Ordenación del Territorio de la Junta de Andalucía a través de la Red de Información Ambiental (REDIAM), gracias a un convenio llamado “Diseño y creación de un repositorio de modelos para la red de información ambiental de Andalucía”. A.J. Pérez-Luque agradece al MICINN por el contrato PTA 2011-6322-I
Massive Loss of Proprioceptive Ia Synapses in Rat Spinal Motoneurons after Nerve Crush Injuries in the Postnatal Period
Altres ajuts: NIH-NINDS R01 NS11196Peripheral nerve injuries (PNIs) induce the retraction from the ventral horn of the synaptic collaterals of Ia afferents injured in the nerve, effectively removing Ia synapses from α-motoneurons. The loss of Ia input impairs functional recovery and could explain, in part, better recovery after PNIs with better Ia synaptic preservation. Synaptic losses correlate with injury severity, speed, and efficiency of muscle reinnervation and requires ventral microglia activation. It is unknown whether this plasticity is age dependent. In neonates, axotomized motoneurons and sensory neurons undergo apoptosis, but after postnatal day 10 most survive. The goal of this study was to analyze vesicular glutamate transporter 1 (VGluT1)-labeled Ia synapses (which also include II afferents) after nerve crush in 10 day old rats, a PNI causing little Ia/II synapse loss in adult rats. We confirmed fast and efficient reinnervation of leg muscles; however, a massive number of VGluT1/Ia/II synapses were permanently lost. This synapse loss was similar to that after more severe nerve injuries involving full transection in adults. In adults, disappearance of ventrally directed Ia/II collaterals targeting α-motoneurons was associated with a prolonged microglia reaction and a CCR2 mechanism that included infiltration of CCR2 blood immune cells. By contrast, microgliosis after P10 injuries was fast, resolved in about a week, and there was no evidence of peripheral immune cell infiltration. We conclude that VGluT1/Ia/II synapse loss in young animals differs in mechanism, perhaps associated with higher microglia synaptic pruning activity at this age and results in larger losses after milder nerve injuries
Time to better integrate paleoecological research infrastructures with neoecology to improve understanding of biodiversity long-term dynamics and to inform future conservation
Anthropogenic pressures are causing a global decline in biodiversity. Successful attempts at biodiversity conservation requires an understanding of biodiversity patterns as well as the drivers and processes that determine those patterns. To deepen this knowledge, neoecologists have focused on studying present-day or recent historical data, while paleoecologists usually study long-term data through the composition of various biological proxies and environmental indicators. By establishing standard protocols or gathering databases, research infrastructures (RIs) have been instrumental to foster exchange and collaboration among scientists within neoecology (e.g. Global Information Biodiversity Facility or National Ecological Observatory Network) and paleoecology (e.g. Paleobiology Database, Neotoma Paleoecology Database or European Pollen Database). However, these two subdisciplines (and their RIs) have traditionally remained segregated although both provide valuable information that combined can improve our understanding of biodiversity drivers and underlying processes, as well as our predictions of biodiversity responses in the future. For instance, integrative studies between paleo- and neoecology have addressed the global challenge of biodiversity loss by validating climate and ecological models, estimating species fundamental niches, understanding ecological changes and trajectories, or establishing baseline conditions for restoration. Supporting and contributing to research infrastructures from both paleo- and neoecology, as well as their further integration, could boost the amount and improve the quality of such integrative studies. We argue this will enable improved capabilities to anticipate the impacts of global change and biodiversity losses. To boost such integration and illustrate our arguments, we (1) review studies integrating paleo- and neoecology to advance in the light of global changes challenge, (2) describe RIs developed in paleoecology, and (3) discuss opportunities for further integration of RIs from both disciplines (i.e. paleo- and neoecology).publishedVersio
Integration of a Landsat Time-Series of NBR and Hydrological Modeling to Assess Pinus Pinaster Aiton. Forest Defoliation in South-Eastern Spain
Epidemiological study of tricuspid regurgitation after cardiac transplantation: does it influence survival?
Observational study[Abstract] Background: Tricuspid valve disease is the most frequent valvulopathy after heart transplantation (HTx). Evidence for the negative effect of post-transplant tricuspid regurgitation (TR) on survival is contradictory. The aim of this study was to analyze the causes of post-transplant TR and its effect on overall mortality. Methods: This is a retrospective observational study of all transplants performed in two Spanish centers (1009 patients) between 2000 and 2019. Of the total number of patients, 809 had no TR or mild TR and 200 had moderate or severe TR. The etiology of TR was analyzed in all cases. Results: The prevalence of moderate and severe TR was 19.8%. The risk of mortality was greater when TR was caused by early primary graft failure (PGF) or rejection (p < 0.05). TR incidence was related to etiology: incidence of PGF-induced TR was higher in the first period, while TR due to rejection and undefined causes occurred more frequently in three periods: in the first year, in the 10-14-year period following HTx, and in the long term (16-18 years). In the multivariable analysis, TR was significantly associated with mortality/retransplantation (HR:1.04, 95% CI:1.01-1.07, p:0.02). Conclusion: The development of TR after HTx is relatively frequent. The annual incidence depends on TR severity and etiology. The risk of mortality is greater in severe TR due to PGF or rejection
Preferential enhancement of sensory and motor axon regeneration by combining extracellular matrix components with neurotrophic factors
After peripheral nerve injury, motor and sensory axons are able to regenerate but inaccuracy of target reinnervation leads to poor functional recovery. Extracellular matrix (ECM) components and neurotrophic factors (NTFs) exert their effect on different neuronal populations creating a suitable environment to promote axonal growth. Here, we assessed in vitro and in vivo the selective effects of combining different ECM components with NTFs on motor and sensory axons regeneration and target reinnervation. Organotypic cultures with collagen, laminin and nerve growth factor (NGF)/neurotrophin-3 (NT3) or collagen, fibronectin and brain-derived neurotrophic factor (BDNF) selectively enhanced sensory neurite outgrowth of DRG neurons and motor neurite outgrowth from spinal cord slices respectively. For in vivo studies, the rat sciatic nerve was transected and repaired with a silicone tube filled with a collagen and laminin matrix with NGF/NT3 encapsulated in poly(lactic-co-glycolic acid) (PLGA) microspheres (MP) (LM + MP.NGF/NT3), or a collagen and fibronectin matrix with BDNF in PLGA MPs (FN + MP.BDNF). Retrograde labeling and functional tests showed that LM + MP.NGF/NT3 increased the number of regenerated sensory neurons and improved sensory functional recovery, whereas FN + MP.BDNF preferentially increased regenerated motoneurons and enhanced motor functional recovery. Therefore, combination of ECM molecules with NTFs may be a good approach to selectively enhance motor and sensory axons regeneration and promote appropriate target reinnervatio
Influence of Regulated Deficit Irrigation on Arbequina’s Crop Yield and EVOOs Quality and Sensory Profile
Regulated deficit irrigation in super-high-density (SHD) olive orchards is a well-known strategy to save water and control plant vigor, without decreasing fruit or oil yield. As there is controversial information about its influence on virgin olive oil quality, a trial was conducted in five SHD olive orchards of Arbequina cultivar in different locations of central, east, north and northeast Spain under full irrigation (FI) and regulated deficit irrigation (RDI) treatments. RDI applied during phase II of fruit growing (40% of total needs) saves more than 20% of water on average, without reductions in olive fruit or extra virgin olive oil (EVOO) yield. No threshold of 3.5 MPa of stem water potential was crossed in any case. RDI modified sterols and the fatty acid profile of EVOOs but not phenols, quality parameters, or the sensory profile. Latitude, altitude, and yearly rainfall have a big impact on some compounds such as campesterol, oleuropein, or margaroleic or linolenic acids.info:eu-repo/semantics/publishedVersio
Heuristic optimization of RC bridge piers with rectangular hollow sections
This paper deals with the economic optimization of reinforced concrete (RC) bridge piers with hollow
rectangular sections and describes the efficiency of three heuristic algorithms: two new variants of the
ant colony optimization (ACO) algorithm, the genetic algorithm (GA) and the threshold acceptance
(TA) algorithm. The GA and TA are used for comparison with the new ACO algorithms. The total number
of variables is 95. All variables are discrete in this analysis. The calibration of the new ACO algorithm recommended
a 250-member ant population and 100 stages. The best solution costs 69,467 euros, which
means savings of about 33% as compared to experience-based design. Finally, results indicate that the
new ACO algorithms are potentially useful for optimizing the costs of real RC structures.This study was funded by the Spanish Ministry of Education (Research Project BIA2006-01444). The authors are grateful for the thorough revision of the manuscript by Dr. Debra Westall.Martínez Martín, FJ.; González Vidosa, F.; Hospitaler Pérez, A.; Yepes Piqueras, V. (2010). Heuristic optimization of RC bridge piers with rectangular hollow sections. Computers and Structures. 88:375-386. https://doi.org/10.1016/j.compstruc.2009.11.009S3753868
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