Ground measurements for the validation of land surface temperatures derived from AATSR and MODIS data

An experimental site was set up in a large, flat and homogeneous area of rice crops for the validation of satellite derived land surface temperature (LST). Experimental campaigns were held in the summers of 2002-2004, when rice crops show full vegetation cover. LSTs were measured radiometrically along transects covering an area of 1 km². A total number of four thermal radiometers were used, which were calibrated and inter-compared through the campaigns. Radiometric temperatures were corrected for emissivity effects using field emissivity and downwelling sky radiance measurements. A database of ground-based LSTs corresponding to morning, cloud-free overpasses of Envisat/Advanced Along-Track Scanning Radiometer (AATSR) and Terra/Moderate Resolution Imaging Spectroradiometer (MODIS) is presented. Ground LSTs ranged from 25 to 32 °C, with uncertainties between ± 0.5 and ± 0.9 °C. The largest part of these uncertainties was due to the spatial variability of surface temperature. The database was used for the validation of LSTs derived from the operational AATSR and MODIS split-window algorithms, which are currently used to generate the LST product in the L2 level data. A quadratic, emissivity dependent split-window equation applicable to both AATSR and MODIS data was checked as well. Although the number of cases analyzed is limited (five concurrences for AATSR and eleven for MODIS), it can be concluded that the split-window algorithms work well, provided that the characteristics of the area are adequately prescribed, either through the classification of the land cover type and the vegetation cover, or with the surface emissivity. In this case, the AATSR LSTs yielded an average error or bias of − 0.9 °C (ground minus algorithm), with a standard deviation of 0.9 °C. The MODIS LST product agreed well with the ground LSTs, with differences comparable or smaller than the uncertainties of the ground measurements for most of the days (bias of + 0.1 °C and standard deviation of 0.6 °C, for cloud-free cases and viewing angles smaller than 60°). The quadratic split-window algorithm resulted in small average errors (+ 0.3 °C for AATSR and 0.0 °C for MODIS), with differences not exceeding ± 1.0 °C for most of the days (standard deviation of 0.9 °C for AATSR and 0.5 °C for MODIS).     

Raw data extraction from electrocardiograms with Portable Document Format

During the last two decades there has been a thorough research and development of standards and protocols in order to cope with different electrocardiogram formats from heterogeneous acquisition systems. Despite the efforts of public and private consortiums on creating a standardized electrocardiogram (ECG) storage format, there is still not a single one. Indeed, there is also the necessity of access to raw data of the ECGs previously acquired. Most of these documents have been saved as Adobe PDF files, since for medical staff it is an easy format for later visualization. However, this format presents difficulties when trying to access original raw data for subsequent studies and signal analysis. In this manner, this paper presents an application that obtains plain numerical data from ECG files stored with PDF format. Data can also be exported to one of the most common file formats in existence, to be easily accessed thereafter.     

Polycyclic aromatic hydrocarbon content in commercial Spanish fatty foods

The levels of polycyclic aromatic hydrocarbons (PAHs) were determined by reversed-phase high-performance liquid chromatography with fluorescence detection in different fatty foods from a Spanish market. The average concentration of the sum of total PAHs in edible vegetable oils was below 25 ng/g, whereas the sum of heavy PAHs did not surpass 5 ng/g. Olive pomace oils obtained before the summer of 2001 were an exception because they were highly contaminated. The effects of different technological processes, such as bleaching, deodorization, and hydrogenation, on PAH concentration in edible oils have been studied. The PAH profiles, as well as the influence of cooking procedures, of other fatty foods (margarine, mayonnaise, and oils from canned fishes) have been examined.     

Metformin Reduces Lipogenesis Markers in Obese Mice Fed a Low-Carbohydrate and High-Fat Diet

Lipogenesis is the process by which fatty acids are synthesized. In metabolic syndrome, an insulin resistant state along with high plasma levels of free fatty acids (FFA) and hyperglycemia may contribute to the lipogenic process. The aim of the present study was to investigate the effects of oral administration of metformin on the expression of lipogenic genes and glycemic profile in mice fed with low‐carbohydrate high‐fat diet by evaluating their metabolic profile. SWISS male mice were divided into 4 groups (N = 7) that were fed with standard (ST), standard plus metformin (ST + MET), low‐carbohydrate high‐fat diet (LCHFD) and low‐carbohydrate high‐fat diet plus metformin (LCHFD + MET) (100 mg kg^?1 diet) diets respectively. Food intake, body weight and blood parameters, such as glucose tolerance, insulin sensitivity, glucose, HDL‐c, total cholesterol, triglycerides, ASL and ALT levels were assessed. Histological analyses were performed on hematoxylin and eosin‐stained epididymal adipose tissue histological specimens. The expression levels of peroxisome proliferator‐activated receptor (PPARγ), sterol regulatory element‐binding protein 1 (SREBP1), fatty acid synthase (FAS) and acetyl‐CoA carboxylase (ACC), were assessed by RT‐PCR. This study showed that metformin decreased adipocyte area, body weight and food consumption in obese animals when compared to the standard group. Furthermore, the expression of lipogenic markers in adipose tissue were diminished in obese animals treated with metformin. This data showed that oral administration of metformin improved glucose and lipid metabolic parameters in white adipose tissue by reducing the expression of lipogenesis markers, suggesting an important clinical application of MET in treating obesity‐related diseases in metabolic syndrome.     

A Multiplex Assay to Assess the Transaminase Activity toward Chemically Diverse Amine Donors

The development of methods to engineer and immobilize amine transaminases (ATAs) to improve their functionality and operational stability is gaining momentum. The quest for robust, fast, and easy-to-use methods to screen the activity of large collections of transaminases, is essential. This work presents a novel and multiplex fluorescence-based kinetic assay to assess ATA activity using 4-dimethylamino-1-naphthaldehyde as an amine acceptor. The developed assay allowed us to screen a battery of amine donors using free and immobilized ATAs from different microbial sources as biocatalysts. As a result, using chromatographic methods, 4-hydroxybenzylamine was identified as the best amine donor for the amination of 5-(hydroxymethyl)furfural. Finally, we adapted this method to determine the apparent Michaelis-Menten parameters of a model immobilized ATA at the microscopic (single-particle) level. Our studies promote the use of this multiplex, multidimensional assay to screen ATAs for further improvement.     

Sociotechnical systems, risk management, and public health: comparing the North Battleford and Walkerton outbreaks

Accidents in different complex sociotechnical systems are rarely compared using the same theoretical framework for risk management. We conducted a comparative analysis of two Canadian public health disasters involving drinking water distribution systems, the North Battleford Cryptosporidium parvum outbreak in April 2001 and the Walkerton E. coli outbreak in May 2000. Both accidents resulted from a complex interaction between all levels of a complex sociotechnical system. However, the low-level physical and individual factors differed in the two cases, whereas, the high-level governmental and regulatory factors tended to be the same. These findings may have implications for the design of public policies to minimize risk in complex sociotechnical systems.     

Practical formula for the evaluation of high-order multiphoton absorption in thin nonlinear media

We present an analytical formula for the fast and accurate evaluation of nonlinear absorption in materials exhibiting an admixture of different multiphoton processes. This approach is specifically addressed for its use in thin films when the slowly varying envelope approximation applies. The contribution of absorptions of distinct order is conveniently averaged in order to use well-known expressions for a single multiphoton process. In the latter case, therefore, our simple expression is reduced toward the exact solution.     

Evaluation of a hydrothermal process for pretreatment of wheat straw—effect of particle size and process conditions

BACKGROUND: Hydrothermal processes are an eco‐friendly processes that provide an interesting alternative for chemical utilization of lignocellulosic materials, in which water and crop residues are the only reagents. In this work the effect of process conditions (size distribution of the wheat straw, temperature and time) was evaluated against production of fermentable products. RESULTS: The use of milled wheat straw fractions as a raw material containing blends of different particle size distribution showed that the latter had an influence on the final sugars in the hydrolysate. Improved values of glucose (21.1%) and xylose yields (49.32%) present in the hydrolysate were obtained with treatment severity factors of 2.77 and 3.36, respectively. Mathematical models were developed aimed at establishing the effect of process conditions on monosaccharide concentration and its degradation in the liquor. CONCLUSION: This work shows that the use of wheat straw blends with various particle sizes has a significant effect on the extraction of fermentable products. The effect of treatment severity, which takes into account both processing time and temperature was also evaluated. These results are of importance for process design. Copyright © 2010 Society of Chemical Industry     

Assessment performance of high-temperature filtering elements

An extensive experimental campaign has been carried out in a hot gas filtration test facility so as to test several filtering elements and configurations, particularly, three different types of bag filters and one ceramic candle. The facility was designed to operate under a wide range of conditions, thus providing an excellent tool for the investigation of hot gas filtration applications for the advanced electrical power generation industry such as IGCC, PFBC or fuel cell technologies.Relevant parameters for the characterisation and optimization of the performance of the filters have been studied for a variety of operating conditions such as filtration velocity, particle concentration, pressure and temperature among others. Pressure drop across the filter, cleaning pulse interval, baseline pressure drop, filtration efficiency and durability of the filter have been investigated for each type considered and dependences on parameters have been established. On top of that, optimal operating conditions and cleaning strategies were determined.The tests results show that bag filters are a suitable alternative for the hot gas filtration due to the better performance and the high efficiency observed, which makes them suitable for industrial applications operating under high temperature high pressure conditions considered within the study (200-370 °C and 4-7.5 barg, respectively).     

Oxygenated compounds derived from glycerol for biodiesel formulation: Influence on EN 14214 quality parameters

The methyl esters of fatty acids (biodiesel) obtained via transesterification of vegetable oils or animal fats are an alternative to current fossil fuels. A large amount of glycerol as a by-product is generated in this process and new applications for this surplus need to be found. Thus, the transformation of glycerol into branched oxygen-containing compounds could be an interesting solution to provide an outlet for increasing glycerol stocks. In this work, several oxygenated compounds, obtained by transformation of glycerol via etherification, esterification and acetalisation, have been assessed as components for biodiesel formulation. Different quality parameters have been evaluated following the procedures listed in the EN 14214 European Standard for biodiesel specifications. These parameters have been correlated with the amount and chemical nature of oxygenated derivate present in the biodiesel. The best performance as component for biodiesel formulation has been achieved by the mixture of ethers produced via etherification of glycerol with isobutylene. The addition of these compounds has not only improved the low-temperature properties of biodiesel (i.e. pour point and cold filter plugging point) and viscosity, but also did not impair other important biodiesel quality parameters analyzed. Although most of the studied oxygenated derivates do not significantly improve any biodiesel property, they do not exert a significant negative effect either. Furthermore, all of them allow an enhancement of overall yield in the biodiesel production. Nevertheless, further improvement could be addressed with a better purification to reduce the presence of non-desired impurities such as di-isobutylenes and unreacted acetic acid, which have a negative influence especially in acid number and oxidation stability.