454 research outputs found

    Testing of a commercial vector network analyzer as low-cost TDR device to measure soil moisture and electrical conductivity

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    Time Domain Reflectometry (TDR) is a non-destructive technique to determine the soil apparent dielectric constant, εa, the volumetric water content, θ, and bulk electrical conductivity, σ. However, the high cost of TDR devices may limit its use. This study evaluates two different low-cost Vector Network Analyzers (VNA) commercially available (NanoVNA), with 1.5 (VNA1.5) and 3.0 (VNA3.0) GHz maximum operating frequency. NanoVNA can be used for measurements of Frequency Domain Reflectometry (FDR) or, after suitable post-processing, for θ and σ TDR measures. Although FDR and TDR are dual procedures, TDR is easier to interpret for soil experiments. The TDR waveforms and εa measured with NanoVNA connected to 10 and 20 cm length three-rod probes immersed in air, distilled water, and a soil column with different θ were compared to those measured using a TDR100 (Campbell Sci.) instrument. The capacity of VNAs to measure σ was evaluated by immersing a 10 cm length three-rod probe in different NaCl-water solutions. Measurements obtained with the VNA and TDR100 were compared in a field test using two-rod 22 cm length TDR probes inserted in soil plots with increasing water content. A robust fit was observed between TDR waveforms registered with the two VNAs and the TDR100. Although VNA3.0 doubles the frequency range of VNA1.5, both devices allowed for good estimates of εa (εaVNA1.5, 3.0 = 1.001 εaTDR100 – 0.2125; R2 = 0.999). These results indicate that the low-cost VNA devices can measure soil water content with similar accuracy and precision as the TDR100. A good agreement (σVNA1.5, 3.0 = 0.999 σCM + 0.0023; R2 = 0.999) was also observed between the σ measured using a conductivity meter (CM) and that estimated with the VNAs. Finally, a good correlation was also observed between θ measured in the field experiment with TDR100 and the VNA1.5 and VNA3.0 devices

    Plant-KBBE: Cornfed: lntegration of advanced mapping and phenotyping methods to identify key alleles for building European maize ideotypes

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    1 página, 3 figuras.-- Trabajo presentado al "Gabi Status Seminar" celebrado en Paris (Francia) en Marzo de 2010.-- et al.The project is funded in the framework of the Transnational (France, Germany, Spain) Cooperation within the PLANT-KBBE initiative, with funding from the Agence Nationale de la Recherche (ANR), the Federal Ministry of Education and Research (BMBF). and the Ministry os Science and Innovation (MICINN).Peer reviewe

    Fingerprints of Anthocyanins and Flavonols in Wild Grapes (Vitis vinifera L. ssp. sylvestris (Gmelin) Hegi)

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    Phenolic compounds are a group of natural products that play an important role in the quality of wines. Most phenolic compounds present in wine are derived from those contained in grapes and extracted from skins, seeds, and pulp during the initial steps of winemaking. Among them, anthocyanins and flavonols are involved in the color of red wines as pigments or copigments and also as precursors of polymeric pigments after reaction with other phenols. Biosynthesis of those phenolics in grapes is regulated by different genes; thus, each grape genotype presents a characteristic phenolic fingerprint, which is modulated by different environmental conditions. In this chapter, the anthocyanins and flavonols composition of different genotypes of wild grapes preserved at El Encin Germplasm Bank has been examined in detail. Wild grapevines are a remarkable genetic resource that may be used in breeding programs to improve the phenolic composition of cultivated grapes and, hence, the quality of red wines

    Effects of the administration of 25(OH) vitamin D3 in an experimental model of chronic kidney disease in animals null for 1- Alpha-hydroxylase

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    The final step in vitamin D activation is catalyzed by 1-alpha-hydroxylase (CYP27B1). Chronic kidney disease (CKD) is characterized by low levels of both 25(OH)D3 and 1,25 (OH)2D3 provoking secondary hyperparathyroidism (2HPT). Therefore, treatments with active or native vitamin D compounds are common in CKD to restore 25(OH)D3 levels and also to decrease PTH. This study evaluates the dose of 25(OH)D3 that restores parathyroid hormone (PTH) and calcium levels in a model of CKD in CYP27B1-/- mice. Furthermore, we compare the safety and efficacy of the same dose in CYP27B1+/+ animals. The dose needed to decrease PTH levels in CYP27B1-/- mice with CKD was 50 ng/g. That dose restored blood calcium levels without modifying phosphate levels, and increased the expression of genes responsible for calcium absorption (TRPV5 and calbindinD- 28K in the kidney, TRPV6 and calbindinD-9k in the intestine). The same dose of 25(OH)D3 did not modify PTH in CYP27B1+/+ animals with CKD. Blood calcium remained normal, while phosphate increased significantly. Blood levels of 25(OH)D3 in CYP27B1-/- mice were extremely high compared to those in CYP27B1+/+ animals. CYP27B1+/+ animals with CKD showed increases in TRPV5, TRPV6, calbindinD-28K and calbindinD-9K, which were not further elevated with the treatment. Furthermore, CYP27B1+/+ animals displayed an increase in vascular calcification. We conclude that the dose of 25(OH)D3 effective in decreasing PTH levels in CYP27B1-/- mice with CKD, has a potentially toxic effect in CYP27B1+/+ animals with CKD.This work was supported by the Instituto de Salud Carlos III PS12/01770, RD12/0021/0026

    Aerosol properties of mineral dust and its mixtures in a regional background of north-central Iberian Peninsula

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    Producción CientíficaTo broaden the knowledge about desert dust (DD) aerosols in western Mediterranean Basin, their fingerprints on optical and microphysical properties are analyzed during DD episodes in the north-central plateau of the Iberian Peninsula between 2003 and 2014. Aerosol columnar properties obtained from the AErosol RObotic NETwork (AERONET), such as aerosol optical depth (AOD), Ångström exponent (AE), volume particle size distribution, volume concentration (VC), sphericity, single scattering albedo, among others, are analyzed in order to provide a general characterization, being some of them compared to particle mass surface concentrations PM10, PM2.5, and their ratio, data obtained from EMEP network. The mean intensity of DD episodes exhibits: AOD440nm = 0.27±0.12, PM10 = 24±18 μg/m3, AE=0.94±0.40 and PM2.5/PM10=0.54±0.16. The AOD and PM10 annual cycles show maximum intensity in March and summer and minima in winter. A customized threshold of AE=1 distinguishes two types of dusty days, those with a prevailing desert character and those of mixed type, which is corroborated by sphericity values. Three well established intervals are obtained with the fine mode volume fraction (VCF/VCT). Coarse-mode-dominated cases (VCF/VCT ≤ 0.2) present a mineral dust character: e.g., particle maximum concentration about 2 μm, non-sphericity, stronger absorption power at shorter wavelengths, among others. The relevance of the fine mode is noticeable in mixtures with a predominance of particles about 0.2-0.3 μm radii. Conditions characterized by 0.2 < VCF/VCT < 0.45 and VCF/VCT ≥ 0.45 present a larger variability in all investigated aerosol properties. Relationships between AOD and columnar particle volume concentration give volume extinction efficiencies between 1.7 and 3.7 μm2/μm3 depending on VCF/VCT. Aerosol scale height is obtained from relationships between surface and columnar concentrations displaying very large values up to 10 km. The uncertainty associated with the transformation between AOD and PM10 can be partially reduced when the aerosol microphysical properties are known.The authors are grateful to Spanish MINECO for the financial support of the FPI grant BES-2012-051868, project CGL2012-33576, and “Juan de la Cierva - Incorporación” grant IJCI-2014-19477. The research leading to these results has received funding from the European Union under grant agreement Nr. 654109 [ACTRIS 2]

    Low-regret climate change adaptation in coastal megacities – evaluating large-scale flood protection and small-scale rainwater detention measures for Ho Chi Minh City, Vietnam

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    Urban flooding is a major challenge for many megacities in low-elevation coastal zones (LECZs), especially in Southeast Asia. In these regions, the effects of environmental stressors overlap with rapid urbanization, which significantly aggravates the hazard potential. Ho Chi Minh City (HCMC) in southern Vietnam is a prime example of this set of problems and therefore a suitable case study to apply the concept of low-regret disaster risk adaptation as defined by the Intergovernmental Panel on Climate Change (IPCC). In order to explore and evaluate potential options of hazard mitigation, a hydro-numerical model was employed to scrutinize the effectiveness of two adaptation strategies: (1) a classic flood protection scheme including a large-scale ring dike as currently constructed in HCMC and (2) the widespread installation of small-scale rainwater detention as envisioned in the framework of the Chinese Sponge City Program (SCP). A third adaptation scenario (3) assesses the combination of both approaches (1) and (2). From a hydrological point of view, the reduction in various flood intensity proxies that were computed within this study suggests that large-scale flood protection is comparable but slightly more effective than small-scale rainwater storage: for instance, the two adaptation options could reduce the normalized flood severity index (INFS), which is a measure combining flood depth and duration, by 17.9 % and 17.7 %, respectively. The number of flood-prone manufacturing firms that would be protected after adaptation, in turn, is nearly 2 times higher for the ring dike than for the Sponge City approach. However, the numerical results also reveal that both response options can be implemented in parallel, not only without reducing their individual effectiveness but also complementarily with considerable added value. Additionally, from a governance perspective, decentralized rainwater storage conforms ideally to the low-regret paradigm: while the existing large-scale ring dike depends on a binary commitment (to build or not to build), decentralized small- and micro-scale solutions can be implemented gradually (for example through targeted subsidies) and add technical redundancy to the overall system. In the end, both strategies are highly complementary in their spatial and temporal reduction in flood intensity. Local decision-makers may hence specifically seek combined strategies, adding to singular approaches, and design multi-faceted adaptation pathways in order to successfully prepare for a deeply uncertain future
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