Gridded precipitation datasets have been developed for data assimilation and evaluation tasks of weather and climate models and for climate analyses. Gridded data uncertainty evaluation is crucial to ...understand the limitations and feasibility. The development of high‐resolution daily gridded precipitation datasets is desirable, but several factors need to be considered, namely rain gauge station availability, their spatial distribution, and orographic and climate characteristics of a study area. Quality assessment of gridded datasets can present difficulties when the influence of these factors is not thoroughly analysed. The main objective of this study was a detailed validation of precipitation grids based on four factors, that is, station density used for grid construction, grid spatial resolution, station altitude, and climate type. To this end, 18 grids were built using six spatial resolutions (0.01°, 0.025°, 0.05°, 0.1°, 0.2° and 0.4°) and three station densities (25, 50 and 75% of all available stations). Results indicate larger differences among the grids as a function of analysed factors. Station density was found to be the main factor, whereas grid spatial resolution had minor importance. However, the latter factor becomes more relevant in areas with strong altitude gradients and when a high station density is available. In addition, weak and moderate precipitation is overestimated on daily grids, whereas heavy precipitation cells are less frequent, reducing data variability. On the contrary, monthly and annual aggregates present less deviation from the observed distribution than daily comparisons. These findings question the applicability of the daily grid datasets for validation studies and climate analysis on a grid cell level.
Gridded data uncertainty evaluation is crucial to understand the limitations and feasibility. The findings question the applicability of the daily grid datasets for validation studies and climate analysis on a grid cell level. On the contrary, temporal aggregates present better results and less deviation from the observed variance than daily comparisons.
Climate classifications are useful to synthesize the physical state of the climate with a proxy that can be directly related to biota. However, they present a potential drawback, namely a strong ...sensitivity because of the use of hard thresholds (step functions). Thus, minor discrepancies in the base data produce large differences in the type of climate. However, such an a priori limitation is also a strength because such sensitivity can be used to better gauge model performance. Although previous attempts of classifying climates of the world using global climate model outputs were encouraging, the applicability of their classifications to impact studies has been limited by past model issues. Notwithstanding the persistence of certain imperfections and limitations in current models, the high‐quality physical simulations from phase six of the Coupled Intercomparison Project (CMIP6) has opened new possibilities in the field, thanks to their improved representation of atmospheric and oceanic physics. The purpose of this paper is twofold: to show that climate classifications from CMIP6 are sufficiently robust for use in impact studies, and to use those classifications for identifying error sources and potential issues that deserve further attention in models. Thus, 52 CMIP6 climate models were evaluated by using three climate classifications schemes, classical Köppen, extended‐Köppen, and modified Thornthwaite. We first assessed model ability to reproduce present climate types by comparing their outputs with observational data. Models performed best for the Köppen and extended‐Köppen classification methods (Cohen's kappa κ = 0.7), and had moderate scores for the Thornthwaite climate classification (κ = 0.4). By tracing back the observed biases, we were able to pinpoint the misrepresentation of dry climates as a major source of error. Another finding was that most models still had some difficulties in representing the seasonal variability of precipitation over several monsoonal regions, thereby yielding the wrong climate type there. Models were also evaluated for future climate. Substantial changes in climate types are projected in the SSP5‐8.5 scenario. These changes include a shrinkage of polar/frigid climates (22%) and an increase of dry climates (7%).
Simulations arising from global climate models can be directly used to understand the global climate. They are however in the form of multidimensional matrices, which makes the outputs difficult to compare and validate. Conversely, climate classifications simplify the complex interactions of the climate system and serve as a single, aggregated parameter for environmental applications. The purpose of this work is to show that climate classifications from GCMs are robust enough to be used in impact studies, and use those classifications to identify potential issues deserving further attention in models.
This paper evaluates Integrated Multi-Satellite Retrievals from GPM (IMERG-F) over Europe for the period 2014–2018 in order to evaluate application of the retrievals to hydrology. IMERG-F is compared ...with a large pan-European precipitation dataset built on rain gauge stations, i.e., the ENSEMBLES OBServation (E-OBS) gridded dataset. Although there is overall agreement in the spatial distribution of mean precipitation (R2 = 0.8), important discrepancies are revealed in mountainous regions, specifically the Alps, Pyrenees, west coast of the British Isles, Scandinavia, the Iberian and Italian peninsulas, and the Adriatic coastline. The results show that the strongest contributors to poor performance are pixels where IMERG-F has no gauges available for adjustment. If rain gauges are available, IMERG-F yields results similar to those of the surface observations, although the performance varies by region. However, even accounting for gauge adjustment, IMERG-F systematically underestimates precipitation in the Alps and Scandinavian mountains. Conversely, IMERG-F overestimates precipitation in the British Isles, Italian Peninsula, Adriatic coastline, and eastern European plains. Additionally, the research shows that gauge adjustment worsens the spatial gradient of precipitation because of the coarse resolution of Global Precipitation Climatology Centre data.
Phosphorylation Catalyzed by Dihydroxyacetone Kinase Gauss, Dominik; Sánchez‐Moreno, Israel; Oroz‐Guinea, Isabel ...
European journal of organic chemistry,
June 22, 2018, Letnik:
2018, Številka:
23
Journal Article
Recenzirano
Odprti dostop
Site‐ and enantioselective kinases have been very useful catalysts for biocatalytic phosphorylations in straightforward syntheses of phosphorylated metabolites. Biocatalytic phosphorylations ...catalyzed by recombinant dihydroxyacetone kinase beyond the dihydroxyacetone substrate have been investigated with quantitative 31P NMR spectroscopy using pyruvate‐kinase‐catalyzed ATP regeneration. A nearly 100 % conversion of d‐glyceraldehyde to d‐glyceraldehyde 3‐phosphate has been found. Interestingly, with pure l‐glyceraldehyde as substrate, practically no formation of l‐glyceraldehyde 3‐phosphate was observed.
Biocatalytic phosphorylations catalyzed by recombinant dihydroxyacetone kinase have been investigated with quantitative 31P NMR spectroscopy and pyruvate‐kinase‐catalyzed ATP regeneration starting with dihydroxyacetone as substrate. A nearly 100 % conversion of d‐glyceraldehyde to d‐glyceraldehyde 3‐phosphate has been found.
FFrancesco Petrarca (1304-1374) contribuyó de manera decisiva a la creación del concepto historiográfico de Edad Media, y a la consideración despectiva de estos siglos de la historia, en gran parte ...debido a su identificación con autores clásicos como Ennio, Cicerón y Tito Livio. El presente artículo centra la atención en las concepciones historiográficas que Petrarca revela en el poema en hexámetros titulado Africa, una obra insuficientemente estudiada pero que se revela fundamental a la hora de comprender tanto las tesis historiográficas del poeta toscano como la creación conceptual de la Edad Media oscura.
Sensitivity Analysis of the WRF Model Fernández-GonzáLez, Sergio; Martín, María Luisa; García-Ortega, Eduardo ...
Journal of applied meteorology and climatology,
03/2018, Letnik:
57, Številka:
3
Journal Article
Recenzirano
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Wind energy requires accurate forecasts for adequate integration into the electric grid system. In addition, global atmospheric models are not able to simulate local winds in complex terrain, where ...wind farms are sometimes placed. For this reason, the use of mesoscale models is vital for estimating wind speed at wind turbine hub height. In this regard, the Weather Research and Forecasting (WRF) Model allows a user to apply different initial and boundary conditions as well as physical parameterizations. In this research, a sensitivity analysis of several physical schemes and initial and boundary conditions was performed for the Alaiz mountain range in the northern Iberian Peninsula, where several wind farms are located. Model performance was evaluated under various atmospheric stabilities and wind speeds. For validation purposes, a mast with anemometers installed at 40, 78, 90, and 118m above ground level was used. The results indicate that performance of the Global Forecast System analysis and European Centre for Medium-Range Weather Forecasts interim reanalysis (ERA-Interim) as initial and boundary conditions was similar, although each performed better under certain meteorological conditions. With regard to physical schemes, there is no single combination of parameterizations that performs best during all weather conditions. Nevertheless, some combinations have been identified as inefficient, and therefore their use is discouraged. As a result, the validation of an ensemble prediction system composed of the best 12 deterministic simulations shows the most accurate results, obtaining relative errors in wind speed forecasts that are <15%.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Background
Iodinated contrast media produce non‐immediate hypersensitivity reactions (NIHR). The goal of this prospective study was to determine the utility of skin tests and the subsequent tolerance ...to negative skin‐tested iodinated contrasts in patients with NIHR caused by iomeprol.
Methods
Prick and intradermal tests with iomeprol, iopamidol, iopromide, and iobitridol were performed in all patients. IV challenge with the causative contrast (iomeprol in 90%) was made if skin tests were negative. In case of a positive skin test with the causal contrast, or a positive challenge test with it, IV challenge test with an alternative, negative skin‐tested contrast was performed in all patients.
Results
Skin tests were positive in 47.6% (20/42) of patients with NIHR induced by iomeprol. Of the 66 challenge tests performed with negative skin‐tested iodinated contrasts, tolerance was confirmed in 35 (53%): 32 iomeron, 2 iobitridol, 1 iopamidol. Cross‐reactivity between iomeprol and iopamidol was 22% (4/20 in patients with positive skin tests and 5/21 in patients with negative skin tests).
Conclusions
Sensitivity of the skin tests was less than 50% NIHRs due to iomeprol, while the negative predictive value of skin tests in patients who tolerated challenges with alternative contrasts (mainly iopamidol) was 53% (35 tolerated out of 66 performed). The cross‐reactivity between iomeprol and iopamidol is high.
This study determines the utility of skin tests and the subsequent tolerance to negative skin‐tested ICM in patients with NIHR caused by iomeprol. In iomeprol‐induced NIHR, skin tests sensitivity is less than 50%, though the negative predictive value of skin tests in patients who tolerated alternative contrasts (mainly iopamidol) is 53%. There is a high cross‐reactivity between iomeprol and iopamidol. Abbreviations: ICM, iodinated contrast media; NIHR, non‐immediate hypersensitivity reactions
The postprandial state seems to have a direct influence on oxidative status and insulin resistance. We determined the effect of an increase in plasma triglycerides after a high‐fat meal on oxidative ...stress in severely obese patients with differing degrees of insulin resistance. The study was undertaken in 60 severely obese persons who received a 60‐g fat overload with a commercial preparation. Measurements were made of insulin resistance, the plasma activity of various antioxidant enzymes, the total antioxidant capacity (TAC) and the plasma concentration of thiobarbituric acid reactive substances (TBARS). The patients with greater insulin resistance had a lower plasma superoxide dismutase (SOD) activity (P < 0.05) and a greater glutathione peroxidase (GSH‐Px) activity (P < 0.05). The high‐fat meal caused a significant reduction in SOD activity and an increase in the plasma concentration of TBARS in all the patients. Only the patients with lower insulin resistance experienced a significant increase in plasma catalase activity (2.22 ± 1.02 vs. 2.93 ± 1.22 nmol/min/ml, P < 0.01), remaining stable in the patients with greater insulin resistance. These latter patients had a reduction in plasma TAC (6.92 ± 1.93 vs. 6.29 ± 1.80 mmol/l, P < 0.01). In conclusion, our results show a close association between the degree of insulin resistance and markers of oxidative stress, both before and after a high‐fat meal. The postprandial state causes an important increase in oxidative stress, especially in severely obese persons with greater insulin resistance. However, we are unable to determine from this study whether there is first an increase in oxidative stress or in insulin resistance.
In the present work, we have analyzed the molecular interactions existing in a 4-n-pentyl-4-cyano-biphenyl (5CB) monomer and its dimer, in the head-tail configuration. The optimized geometrical ...structures of the monomer and dimer were obtained using the theoretical level wB97-XD/6-311G++(d,p). The intermolecular interactions were analyzed through the non-covalent interaction index (NCI) and the localized molecular orbital energy decomposition analysis method (LMO-EDA). Our results suggest that the antiparallel alignment of the 5CB liquid crystal is caused by attractive contributions arising from the intermolecular interactions between the aromatic rings. Furthermore, these interactions were found to cause deformations in the geometries of the monomers forming the dimer. Keywords: 5CB, dimer, DFT, intermolecular.
The usefulness of traditional plants in Mexico to treat human ailments has been known since ancient times. This work evaluated the antimicrobial, anticoagulant, antioxidant, cytotoxic, and ...anti-inflammatory potential of ethanolic extracts of Aloe vera, Equisetum arvense, Mimosa tenuiflora, Lippia graveolens, and Syzygium aromaticum. The antimicrobial activity of the extracts was evaluated against Streptococcus mutans and Streptococcus sorbinus; a significant inhibitory effect of the L. graveolens extract on both bacteria was observed at concentration levels of 250 µg/mL and greater. The anticoagulant activity was evaluated in terms of prothrombin time (PT) and activated partial thromboplastin time (APTT), A. vera and M. tenuiflora extracts showed no significant difference (p ˂ 0.05) in PT compared with the control, and for APTT the extracts of A. vera, L. graveolens, and S. aromaticum decreased the APTT significantly (p ˂ 0.05) compared with the control. The antioxidant potential by DPPH assay indicated that the E. arvense extract behaved statistically the same as the control. The cytotoxic activity was evaluated in HGF-1 cells using the fluorometric microculture cytotoxicity assay technique, and none of the extracts was toxic at 125 and 250 µg/mL concentrations. Finally, the anti-inflammatory activity was evaluated using ELISA, where the A. vera extract showed the best anti-inflammatory capacity. Further research on the search for bioactive metabolites and elucidation of action mechanisms of the most promising extracts will be carried out.
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