Essential Biodiversity Variables Pereira, H. M.; Ferrier, S.; Walters, M. ...
Science (American Association for the Advancement of Science),
01/2013, Volume:
339, Issue:
6117
Journal Article
Peer reviewed
Reducing the rate of biodiversity loss and averting dangerous biodiversity change are international goals, reasserted by the Aichi Targets for 2020 by Parties to the United Nations (UN) Convention on ...Biological Diversity (CBD) after failure to meet the 2010 target (1, 2). However, there is no global, harmonized observation system for delivering regular, timely data on biodiversity change (3). With the first plenary meeting of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) soon under way, partners from the Group on Earth Observations Biodiversity Observation Network (GEO BON) (4) are developing-and seeking consensus around-Essential Biodiversity Variables (EBVs) that could form the basis of monitoring programs worldwide.
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In this article, the occurrence of stator faults in line-start permanent magnet synchronous motors is analyzed. A dynamic model of the motor was developed in MATLAB/Simulink, which considers the ...performance of the motor both in healthy conditions and under the occurrence of interturn short-circuit faults, at an early stage of development. To validate the presented approach, simulation results, covering the full range of operation, and different fault severity levels, are compared with the motor experimental performance. The output of the proposed model, namely voltages and currents, present a good agreement with experimental results, demonstrating the accuracy of the proposed model. Additionally, an online fault diagnostic technique is explored, demonstrating its potentiality.
Abstract Macrophages are frequently identified in solid tumors, playing important roles in cancer progression. Their remarkable plasticity makes them very sensitive to environmental factors, ...including the extracellular matrix (ECM). In the present work, we investigated the impact of human tumor colorectal matrices on macrophage polarization and on macrophage-mediated cancer cell invasion. Accordingly, we developed an innovative 3D-organotypic model, based on the decellularization of normal and tumor tissues derived from colorectal cancer patients' surgical resections. Extensive characterization of these scaffolds revealed that DNA and other cell constituents were efficiently removed, while native tissue characteristics, namely major ECM components, architecture and mechanical properties, were preserved. Notably, normal and tumor decellularized matrices distinctly promoted macrophage polarization, with macrophages in tumor matrices differentiating towards an anti-inflammatory M2-like phenotype (higher IL-10, TGF-β and CCL18 and lower CCR7 and TNF expression). Matrigel invasion assays revealed that tumor ECM-educated macrophages efficiently stimulated cancer cell invasion through a mechanism involving CCL18. Notably, the high expression of this chemokine at the invasive front of human colorectal tumors correlated with advanced tumor staging. Our approach evidence that normal and tumor decellularized matrices constitute excellent scaffolds when trying to recreate complex microenvironments to understand basic mechanisms of disease or therapeutic resistance.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
In many families, plants undergo floral resupination by twisting through approximately 180° during floral development so that the flower is effectively positioned upside down. In most orchids, ...resupination results in the median petal (i.e., the labellum) becoming lowermost, which plays a crucial role in pollination by serving as a landing platform or as a trapping device, or both. Incomplete resupination is predicted to lead to reduced pollination, although tests of this assumption are still lacking.
We investigated the effect of resupination using Phragmipedium vittatum, a rare lady's slipper orchid whose specialized labellum forms a trapping device. First, we surveyed the natural occurrence of incomplete resupination. Then we manipulated flowers into non‐ (≈0°), half‐ (≈90°), and fully resupinate (≈180°) positions to test the effect of orientation on pollen smear removal and deposition by pollinators (female hoverflies).
We found that ca. 10% of flowers in the natural population were not fully resupinate, being either non‐ (upward, 0–60°) or half‐resupinate (sideward, 60–120°). The change in orientation prevented the effectiveness of pollination by hoverflies since no pollen smear removal or deposition were found in flowers from non‐ and half‐resupinate treatments. Although these flowers still attracted hoverflies, they were not trapped effectively.
As this orchid is incapable of autonomous self‐pollination, flowers that do not resupinate fail to set fruits. These results highlight the importance of correct floral orientation provided by resupination to ensure pollination in orchids and other resupinate flowers.
Floral resupination, the twist of ca. 180° during development, is essential for pollen transport in a slipper orchid, highlighting the importance of reorientation to ensure pollination in orchids and other resupinate flowers.”
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
This study evaluated the median lethal concentration of silver nanoparticles and their effects in fish tambaqui Colossoma macropomum. Therefore, an acute toxicity assay was carried out in completely ...randomized design evaluating six different concentrations of silver nanoparticles on blood parameters of tambaqui. The silver nanoparticles were produced by chemical reduction with polyvinyl alcohol (AgNP-PVA). The lethal concentration 50% (LC50) was estimated using probit regression. The blood was collected, analyzed and the data were submitted to T-test (dying x surviving fish) and Tukey test (surviving fish). An increase in glucose, hematocrit, total plasma protein, hemoglobin, erythrocytes, leukocytes, monocytes, and neutrophils as well as reduced MCV (mean corpuscular volume) in dying fish compared to surviving fish were observed. Survived fish exposed to 187.5 µg/L showed an increase in hematocrit, MCV, and MCH and a reduction in erythrocytes, total numbers of leukocyte, thrombocyte, lymphocyte, and neutrophil. The fish exposed to concentrations below 125 µg/L, had returned the blood parameter to baselines compared to control. The estimated LC50 was 165.09 µg/L and was classified as highly toxic for the fish tambaqui. In higher concentrations, it causes an acute respiratory toxicity, but in concentrations below 125 µg/L, the fish can adapt to the stressing agent.
Developing novel and efficient electrocatalysts is vital to overcome most of the technical and economic issues associated with the hydrogen production via water electrolysis. Herein, Pd-based alloy ...nanoparticles, namely AuPd and FePd, assembled on reduced graphene oxide (rGO) are investigated as cathode electrocatalysts for hydrogen evolution reaction (HER) in alkaline water electrolysis. TEM, HR-TEM, XRD and ICP-MS are used to carry out the structural and morphological characterisation of the as-prepared rGO-AuPd and rGO-FePd nanocomposites and their electrocatalytic activity and stability is studied by voltammetry and chronoamperometry measurements. rGO-AuPd and rGO-FePd show HER onset overpotentials of 80 and 140 mV, respectively. A Tafel slope of 149 mV dec−1 is evaluated for rGO-AuPd at 25 °C, while rGO-FePd has worse performance. It is shown that rGO-AuPd nanocomposites are good candidates for application as novel electrocatalysts for the HER in alkaline media.
•rGO-MPd (M: Au, Fe) composite electrocatalysts were synthesised and tested for HER.•The prepared NPs and composites were characterised by TEM, HR-TEM, XRD, and ICP-MS.•Electrocatalytic activity and stability was studied by voltammetry and chronoamperometry.•rGO-Au48Pd52 nanocomposite shows higher electrocatalytic activity for HER in alkaline media.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Typical direct liquid fuel cells (DLFCs) use a liquid fuel and O2 as the oxidant. However, for applications where O2 is not available (e.g., space and underwater), the gas has been replaced by H2O2 ...as a liquid oxidant. This work presents a study of various ceramic disc electrodes with K2NiO4 structure and nominal compositions La2NiO4, La2CuO4, La1.9Pr0.1CuO4, La1.9Sr0.1CuO4, La1.8Ce0.2NiO4, La1.9Pr0.1NiO4, La1.8Pr0.2NiO4 and La1.9Sr0.1NiO4 to assess their stability and activity for the hydrogen peroxide reduction reaction (HPRR) in alkaline media. Stability tests conducted in 2 M NaOH show that Ni and Cu are readily dissolved, as occurs for substituting elements such as Sr, in agreement with calculated Pourbaix diagrams. Such degradation affects the surface of the materials, which is depleted of transition metals. This has consequences for the ORR and HPRR activity due to formation of a La-rich passivation layer on the surface. Only La2CuO4 and La1.8Ce0.2NiO4 display HPRR activity at around −0.25 V vs. RHE. An attempt is made to correlate the composition, chemical stability and electrochemical behaviour of these materials based on known molecular-orbital models proposed for the oxygen reduction reaction.
This paper addresses the diagnostics of stator faults in three-phase line-start permanent magnet synchronous motors. More traditional fault diagnostic methodologies are unable to properly diagnose ...stator inter-turn short-circuit faults in three-phase motors under unbalanced supply voltage conditions, since both conditions impact the fault indicators used for inter-turn short-circuit fault diagnostics in a similar way. In this paper, the relation between the symmetrical components of the three-phase quantities and the harmonic components of the Extended Park’s Vector Approach (EPVA) is established. It is proved that the negative component and the EPVA harmonic component at a frequency twice the supply frequency are directly related to the fault occurrence. It is also proved that the healthy motor negative impedance is constant and not load-dependent. Based on this, the negative impedance/admittance is indirectly analyzed, through the combined use of the Extended Park´s Vector Approach of both voltage and current, and is explored for the fault diagnostics. Experimental results, obtained for different load torques, unbalanced supply voltage values, and fault severity levels, show that inter-turn short-circuit fault diagnostics can be achieved even under unbalanced supply voltage conditions based on the analysis of the motor admittance, at a frequency twice the supply frequency, that is the negative sequence admittance.
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