Clipping herbaceous vegetation improves early performance of planted seedlings of the Mediterranean shrub Quercus coccifera

We tested how the conditions resulting from alternative management strategies addressed to mitigate abiotic and biotic limitations to plant establishment affect the performance of planted Quercus coccifera seedlings. This species is a xerophytic and heliophillous Mediterranean shrub, of interest for the restoration of abandoned farmland. We hypothesised that release from herb competition by clipping would allow Q. coccifera seedlings to cope more efficiently with water shortage by adjusting their mass allocation pattern. We established three environments of herb competition: absence of competition (AC), reduced competition by clipping (RC), and total competition (TC); and applied two irrigation treatments: low and high irrigation. We measured soil moisture at different depths, above- and below-ground herb biomass, and evaluated seedling responses, such as mortality, growth, biomass allocation, and morphological and physiological features. The TC treatment reduced water availability more than the RC treatment, in agreement with the highest water stress of seedlings under TC conditions. Irrigation increased above- and below-ground herb biomass, whereas clipping reduced herb production. Release of herb competition by clipping increased seedling survivorship by one order of magnitude and resulted in a growth rate comparable to the absence of competition. This growth was mostly related to carbon gain allocated to roots. The competition intensity imposed by treatments was related to a parallel reduction in total plant leaf area, biomass allocated to leaves and shoot:root ratio, and an increase in biomass allocated to roots and leaf mass area. The negative effects of herbs on Q. coccifera seedlings seem the result of competition for both water and light, in contrast with previous research with more mesic Quercus species, for which competition is primarily for water. Clipping of herbs is a feasible technique that greatly improved seedling performance, and thus a valuable alternative to herbicide application, common in native plantations aimed at restoring Mediterranean farmland

High repetition rate UV ultrafast laser inscription of buried channel waveguides in Sapphire: Fabrication and fluorescence imaging via ruby R lines

We report on the fabrication of buried cannel waveguides in Sapphire crystals by 250-kHz high repetition rate ultrafast laser inscription with 385 nm pulses. The propagation properties of the waveguides were studied as a function of the writing conditions. The micro-fluorescence analysis of the R lines generated by trace Cr3+ dopant in Sapphire is used to elucidate the micro-structural modifications induced in the crystal network. It is revealed that waveguide has been formed due to local dilatation of the Sapphire network generated in the surroundings of the focal volume. The refractive index increment due to the dilatation induced electronic polarizability enhancement has been estimated to be of the order of Δn ≈10-4. © 2009 Optical Society of America

Thermal stability of microstructural and optical modifications induced in sapphire by ultrafast laser filamentation

We report on the thermal stability of both structural and optical micromodifications created by ultrafast laser written filaments in sapphire crystals. By using the Cr3+ traces as optical probes, we have concluded that the filaments are constituted by both reversible and nonreversible defects with very different spatial locations. The strain field measured from the analysis of R lines has been found to be erased at the same time when the reversible centers are recombined (∼1100 °C). This fact seems to indicate that these defects act as pinning centers for the induced stress. Furthermore, we have found that the waveguide generated in the proximity of the filament disappear for annealing temperatures above 1100 °C. This clearly supports the assumption that waveguiding is produced by the strain stress induced refractive index increment based on the dominant electronic polarizability enhancement. © 2010 American Institute of Physics

Identifying past social-ecological thresholds to understand long-term temporal dynamics in Spain

A thorough understanding of long-term temporal social-ecological dynamics at the national scale helps to explain the current condition of a country’s ecosystems and to support environmental policies to tackle future sustainability challenges. We aimed to develop a methodological approach to understand past long-term (1960-2010) social-ecological dynamics in Spain. First, we developed a methodical framework that allowed us to explore complex social-ecological dynamics among biodiversity, ecosystem services, human well-being, drivers of change, and institutional responses. Second, we compiled 21 long-term, national-scale indicators and analyzed their temporal relationships through a redundancy analysis. Third, we used a Bayesian change point analysis to detect evidence of past social-ecological thresholds and historical time periods. Our results revealed that Spain has passed through four socialecological thresholds that define five different time periods of nature and society relationships. Finally, we discussed how the proposed methodological approach helps to reinterpret national-level ecosystem indicators through a new conceptual lens to develop a more systems-based way of understanding long-term social-ecological patterns and dynamicsThis work was supported by the Biodiversity Foundation (http://www.fundacion-biodiversidad.es/) of the Spanish Ministry of Agriculture, Food and Environment. Partial financial support was also provided by the Ministry of Economy and Competitiveness of Spain (project CGL2014-53782-P: ECOGRADIENTES). The Spanish National Institute for Agriculture and Food Research and Technology (INIA) funded Marina García-Llorente as part of the European Social Fund. Blanca González García-Mon participated in this article as a “la Caixa” Banking Foundation scholar. The funders had no role in the study design, data collection and analysis, preparation of the report, or the decision to submit the study for publicatio

Venezuela: el ocaso de una democracia

Este artículo plantea la tesis de que, para su estudio, la actual política exterior venezolana debe relacionarse con dos importantes cambios observados en lo doméstico y en lo internacional, entendidos como driving forces. En primer lugar, la creciente erosión de la democracia y el fortalecimiento de regímenes iliberales en el mundo y, en segundo lugar, la transformación geopolítica del orden internacional. Basándonos en los principios del neorrealismo, la jerarquía y el balance de poder en un sistema internacional donde la concepción clásica de la soberanía y de la discrecionalidad diplomática están cambiando, se concluye que Venezuela se ha convertido en un interesante caso para conocer más sobre esos procesos.This article puts forward a central thesis, namely, that for its study, Venezuela’s current foreign policy must be related to two important changes at the domestic and international levels and defined as driving forces. First, the increasing erosion of democracy and the strengthening of illiberal regimes in the world; secondly, the significant geopolitical transformation of the international order. Based on neorealism tenets, the hierarchy and balance of power in an international system where the classical conception of sovereignty and diplomatic discretion are changing, the authors deem that Venezuela has become an important case to have a better understanding of those processes

Upconverting nanoparticles as primary thermometers and power sensors

Luminescence thermometry is a spectroscopic technique for remote temperature detection based on the thermal dependence of the luminescence of phosphors, presenting numerous applications ranging from biosciences to engineering. In this work, we use the Er3+ emission of the NaGdF4/NaGdF4:Yb3+,Er3+/NaGdF4 upconverting nanoparticles upon 980 nm laser excitation to determine simultaneously the absolute temperature and the excitation power density. The Er3+ 2H11/2→4 I15/2 and 4 S3/2→4 I15/2 emission bands, which are commonly used for thermometric purposes, overlap with the 2 H9/2 →4 I13/2 emission band, which can lead to erroneous temperature readout. Applying the concept of luminescent primary thermometry to resolve the overlapping Er3+ transitions, a dual nanosensor synchronously measuring the temperature and the delivered laser pump power is successfully realized holding promising applications in laser-supported thermal therapies.publishe

Infrared-Emitting QDs for Thermal Therapy with Real-Time Subcutaneous Temperature Feedback

Nowadays, one of the most exciting applications of nanotechnology in biomedicine is the development of localized, noninvasive therapies for diverse diseases, such as cancer. Among them, nanoparticle-based photothermal therapy (PTT), which destroys malignant cells by delivering heat upon optical excitation of nanoprobes injected into a living specimen, is emerging with great potential. Two main milestones that must be reached for PTT to become a viable clinical treatment are deep penetration of the triggering optical excitation and real-time accurate temperature monitoring of the ongoing therapy, which constitutes a critical factor to minimize collateral damage. In this work, a yet unexplored capability of near-infrared emitting semiconductor nanocrystals (quantum dots, QDs) is demonstrated. Temperature self-monitored ­QD-based PTT is presented for the first time using PbS/CdS/ZnS QDs emitting in the second biological window. These QDs are capable of acting, simultaneously, as photothermal agents (heaters) and high-resolution fluorescent thermal sensors, making it possible to achieve full control over the intratumoral temperature increment during PTT. The differences observed between intratumoral and surface temperatures in this comprehensive investigation, through different irradiation conditions, highlight the need for real-time control of the intratumoral temperature that allows for a dynamic adjustment of the treatment conditions in order to maximize the efficacy of the therapyThis project has been supported by the Spanish Ministerio de Economía y Competitividad under project and MAT2013-47395-C4-1-R. B. del Rosal thanks Universidad Autónoma de Madrid for an FPI grant. F. Ren acknowledges scholarship support from the Fonds de recherche du Québec – Nature et technologies (FRQNT) under the Programme de Bourses d’Excellence (Merit Scholarship Program for Foreign Students

What level of native beetle diversity can be supported by forestry plantations? A global synthesis

Forestry plantations have been established globally to meet timber demands, often leading to the conversion of natural to artificial forests. Forestry plantations may support natural elements of forest biodiversity, but understanding their role in the maintenance of biodiversity is a crucial question. We performed a meta-analysis of 48 studies to determine how forestry plantations relative to natural forests influence the species richness and abundance of three important coleopteran groups (i.e., ground beetles, rove beetles, and dung beetles), given their essential role in ecosystem functioning. We assessed whether beetle responses depended on taxonomic group, geographical location, native or exotic character of the planted tree species, and associated management characteristics (i.e., composition, size, age, and connectivity of the plantations). We found that forestry plantations negatively affected coleopteran species richness and abundance compared to natural forests. The negative impact was most severe in plantations with exotic tree species and located in tropical biomes. Species richness and abundance of beetles significantly increased with plantation age in native plantations but decreased in exotic ones. Also, small plantations close to native forest had higher beetle species richness and abundance than ones located far away from native forest. Stopping the conversion of natural forests to plantations, promoting the use of native tree species, and lengthening rotations are critical for allowing biodiversity recovery in forestry plantations, combined with a robust conservation strategy to protect threatened biodiversity and ecosystem functioning.Hungarian Basic Research FundRemedinalNatural Environment Research CouncilMinisterio de Ciencia e Innovació

Gravel pits support waterbird diversity in an urban landscape

We assessed the benefit of 11 gravel pits for the settlement of waterbird communities in an urbanized area lacking natural wetlands. Gravel pits captured 57% of the regional species pool of aquatic birds. We identified 39 species, among which five were regionally rare. We used the Self Organizing Map algorithm to calculate the probabilities of presence of species, and to bring out habitat conditions that predict assemblage patterns. The age of the pits did not correlate with assemblage composition and species richness. There was a positive influence of macrophyte cover on waterbird species richness. Larger pits did not support more species, but species richness increased with connectivity. As alternative wetland habitats, gravel pits are attractive to waterbirds, when they act as stepping stones that ensure connectivity between larger natural and/or artificial wetlands separated in space