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We investigate how evaporation changes depending on the scales in the Altiplano region of the Atacama Desert. More specifically, the temporal evolution from the climatological to the sub-diurnal scales on a high-altitude saline lake ecosystem. We analyse the evaporation trends over 70 years (1950-2020) at a high-spatial resolution. The method is based on the downscaling of 30-km hourly resolution ERA5 reanalysis data to 0.1-km spatial resolution data, using artificial neural networks to analyze the main drivers of evaporation. To this end, we use the Penman open water evaporation equation, modified to compensate for the energy balance non-closure and the ice cover formation on the lake during the night. Our estimation of the hourly climatology of evaporation shows a consistent agreement with eddy-covariance measurements and reveals that evaporation is controlled by different drivers depending on the time scale. At the sub-diurnal scale, mechanical turbulence is the primary driver of evaporation, and at this scale, it is not radiation-limited. At the seasonal scale, more than 70% of the evaporation variability is explained by the radiative contribution term. At the same scale, and using a large-scale moisture tracking model, we identify the main sources of moisture to the Chilean Altiplano. In all cases, our regime of precipitation is controlled by large-scale weather patterns closely linked to climatological fluctuations. Moreover, seasonal evaporation influences significantly the saline lake surface spatial changes. From an interannual scale perspective, evaporation increased by 2.1 mm per year during the entire study period, according to global temperature increases. Finally, we find that yearly evaporation depends on the El Niño Southern Oscillation (ENSO), where warm and cool ENSO phases are associated with higher evaporation and precipitation rates, respectively. Our results show that warm ENSO phases increase evaporation rates by 15%, whereas cold phases decrease it by 2%. [ABSTRACT FROM AUTHOR]

This study presents a fine scale simulation approach to assess the representativity of ammonia (NH3) measurements in proximity of an emission source. Close proximity to emission sources (< 5 km) can introduce a bias in regionally representative measurements of the NH3 molar fraction and flux. Measurement sites should therefore be located a significant distance from emission sources, but such requirements are poorly defined and can be difficult to meet in densely agricultural regions. This study presents a consistent criterium to assess the regional representativity of NH3 measurements in proximity of an emission source, calculating variables that quantify the NH[sub 3] plume dispersion using a series of numerical experiments at a fine resolution (20 m). Our fine scale simulation framework with explicitly resolved turbulence enables us to distinguish between the background NH3 and the emission plume, including realistic representations of NH3 deposition and chemical gas-aerosol transformations. We introduce the concept of blending-distance, based on the calculation of turbulent fluctuations, to systematically analyze the impact of the emission plume on simulated measurements, relative to this background NH3. This sensitivity analysis includes systematic experiments varying meteorological factors, emission/deposition and NH3 dependences. Considering these sensitivities, we find that NH3 measurements should be located at a minimum distance of 0.5 - 2.5 km and 1-3.5 km from an emission source, for NH3 molar fraction and flux measurements respectively. The simulation framework presented here can easily be adapted to local conditions and paves the way for future ammonia research at high spatio-temporal resolution. [ABSTRACT FROM AUTHOR]

The water and energy transfers at the interface between the Earth’s surface and the atmosphere should be correctly simulated in numerical weather and climate models. This implies the need for a realistic and accurate representation of land cover (LC), including appropriate parameters for each vegetation type. In some cases, the lack of information and crude representation of the surface leads to errors in the simulation of soil and atmospheric variables. This work investigates the ability of the Weather Research and Forecasting (WRF) model to simulate surface heat fluxes in a heterogeneous area of southern France, using several possibilities for the surface representation. In the control experiments, we used the default LC database in WRF, which differed significantly from the actual LC. In addition, sub-grid variability was not taken into account since the model uses, by default, only the surface information from the dominant LC category in each pixel (dominant approach). To improve this surface simplification, we designed three new interconnected numerical experiments with four widely-used land-surface models (LSMs) in WRF. The first one consisted of using a more realistic and higher-resolution LC dataset over the area of analysis. The second experiment aimed at investigating the effect of using a mosaic approach, where 30-m sub-grid surface information was used to calculate the final grid fluxes, based on weighted averages from values obtained for each LC category. Finally, in the third experiment, we increased the model stomatal conductance for conifer forests, due to the large fluxes errors associated with this vegetation type in some LSMs. The simulations were evaluated with gridded area-averaged fluxes calculated from five tower measurements obtained during the Boundary Layer Late Afternoon and Sunset Turbulence (BLLAST) field campaign. The results from the experiments differed depending on the LSM and displayed a high dependency of the simulated fluxes on the specific LC definition within the grid cell, an effect that was enhanced with the dominant approach. The simulation of the fluxes improved using the more realistic LC dataset except for the LSMs that included extreme surface parameters for the coniferous forest. The mosaic approach produced fluxes more similar to reality and served to improve, especially, the latent heat flux simulation of each grid cell. Therefore, our findings stress the need to include an accurate surface representation in the model, including soil and vegetation sub-grid information with updated surface parameters for some vegetation types, as well as seasonal and man-made changes. This will improve the modelled heat fluxes and ultimately yield more realistic atmospheric processes in the model. [ABSTRACT FROM AUTHOR]

The CloudRoots field experiment was designed to obtain a comprehensive observational data set that includes soil, plant and atmospheric variables to investigate the interaction between a heterogeneous land surface and its overlying atmospheric boundary layer at the sub- hourly and sub-kilometre scale. Our findings demonstrate the need to include measurements at leaf level in order to obtain accurate parameters for the mechanistic representation of photosynthesis and stomatal aperture. Once the new parameters are implemented, the mechanistic model reproduces satisfactorily the stomatal leaf conductance and the leaf-level photosynthesis. At the canopy scale, we find a consistent diurnal pattern on the contributions of plant transpiration and soil evaporation using different measurement techniques. From the high frequency and vertical resolution state variables and CO2 measurements, we infer a profile of the plant assimilation that shows a strong non- linear behaviour. Observations taken by a laser scintillometer allow us to quantify the non-steadiness of the surface turbulent fluxes during the rapid changes driven by perturbation of the photosynthetically active radiation (PAR) by clouds, the so-called cloud flecks. More specifically, we find two-minute delays between the cloud radiation perturbation and ET. The impact of surface heterogeneity was further studied using ET estimates infer from the sun-induced fluorescence data and show small variation of ET in spite of the plant functional type differences. To study the relevance of advection and surface heterogeneity on the land-atmosphere interaction, we employ a coupled surface-atmospheric conceptual model that integrates the surface and upper-air observations taken at different scales: from the leaf-level to the landscape. At the landscape scale, we obtain the representative sensible heat flux that is consistent with the evolution of the boundary-layer depth evolution. Finally, throughout the entire growing season, the wide variations in stomatal opening and photosynthesis lead to large variations of plant transpiration at the leaf and canopy scales. The use of different instrumental techniques enables us to compare the total ET at various growing stages, from booting to senescence. There is satisfactory agreement between evapotranspiration of total ET, but the values remain sensitive to the scale at which ET is measured or modelled. [ABSTRACT FROM AUTHOR]

Abstract: Pseudohypoaldosteronism (PHA) comprises a diverse group of rare diseases characterized by sodium and potassium imbalances incorrectly attributed to a defect in aldosterone production. Two different forms of PHA have been described, type I (PHAI) and type II (PHAII). PHAI has been subclassified into renal and systemic. Given the rarity and heterogeneity of this group of disorders we report three patients who carry PHA and a brief revision of current literature focused on the comparative analysis of PHAI and PHAII. Cases 1 and 2 presented with hyponatremia, hyperkalemia, metabolic acidosis and elevated plasma aldosterone and plasma renin activity in the neonatal period. Sequence analysis of the NRC2 gene demonstrated a novel heterozygous c.403C>T mutation in case 1 and a complete deletion in case 2, confirming the diagnosis of renal PHAI. Case 3 was a 4-year-old with hypertension, hyperkalemia, metabolic acidosis, normal plasma aldosterone and decreased plasma renin activity. Sequence analysis of the CUL3 gene demonstrated a previously unreported heterozygous c.1377+2T>3 mutation, confirming the diagnosis of PHAII-E. We highlight the importance of the determination of plasma aldosterone and plasma renin activity in the context of persistent sodium and potassium imbalances in children. [ABSTRACT FROM AUTHOR]

Background: Influenza virus infections are responsible for significant morbidity and mortality in both pediatric and adult populations worldwide. Rapid and accurate diagnosis of influenza is necessary for appropriate patient management during the influenza season and for optimal utilization of anti-influenza therapy. We prospectively tested the accuracy of a simple and rapid diagnostic method. Methods: Ninety-eight samples (nasal and pharyngeal swabs) from patients with upper respiratory tract infection symptoms who presented to primary healthcare centres in Barcelona (Spain) were prospectively analyzed. The samples were collected as part of influenza surveillance program. Samples that had enough volume to make the new test after aliquoting the amount needed to perform routine tests were included. None of the samples were pre-selected as a result of their status in relation to influenza virus. Samples were analyzed by in-house real-time PCR and Alere™ i Influenza A & B (Alere™ i), which uses isothermal amplification of nucleic acids for the qualitative detection of influenza A and B in nasal swabs transported in viral transport media. The two techniques were compared by positive percent agreement (PPA) and negative percent agreement (NPA). Statistical analysis was performed with Stata. Results: Of the 98 samples analysed 90 were concordant; 46 (46.9%) were positive and 44 (44.9%) were negative. Five samples showed invalid results with the Alere™ i test and could be not re-tested due to insufficient sample volume and were not included in the final statistical analysis. In the 93 remaining samples, the Alere™ i test showed 97% of accuracy having correctly classified 90 samples. We obtained discordant results in 3 samples (3%). The PPA was 93.8% for influenza A and 94.1% for influenza B, and NPA was 100% for influenza A and influenza B virus. In addition, the Alere™ i was very rapid (15 minutes or less) and extremely easy to use. Conclusions: The Alere™ i test provided a good correlation compared to the real-time PCR test for the diagnosis of influenza. Since this method can be performed in minutes, it allows immediate, accurate clinical decisions to prescribe appropriate antiviral treatment or isolation of patients. [ABSTRACT FROM AUTHOR]

Background: Influenza virus infections are responsible for significant morbidity and mortality in both pediatric and adult populations worldwide. Rapid and accurate diagnosis of influenza is necessary for appropriate patient management during the influenza season and for optimal utilization of anti-influenza therapy. We prospectively tested the accuracy of a simple and rapid diagnostic method. Methods: Ninety-eight samples (nasal and pharyngeal swabs) from patients with upper respiratory tract infection symptoms who presented to primary healthcare centres in Barcelona (Spain) were prospectively analyzed. The samples were collected as part of influenza surveillance program. Samples that had enough volume to make the new test after aliquoting the amount needed to perform routine tests were included. None of the samples were pre-selected as a result of their status in relation to influenza virus. Samples were analyzed by in-house real-time PCR and Alere™ i Influenza A & B (Alere™ i), which uses isothermal amplification of nucleic acids for the qualitative detection of influenza A and B in nasal swabs transported in viral transport media. The two techniques were compared by positive percent agreement (PPA) and negative percent agreement (NPA). Statistical analysis was performed with Stata. Results: Of the 98 samples analysed 90 were concordant; 46 (46.9%) were positive and 44 (44.9%) were negative. Five samples showed invalid results with the Alere™ i test and could be not re-tested due to insufficient sample volume and were not included in the final statistical analysis. In the 93 remaining samples, the Alere™ i test showed 97% of accuracy having correctly classified 90 samples. We obtained discordant results in 3 samples (3%). The PPA was 93.8% for influenza A and 94.1% for influenza B, and NPA was 100% for influenza A and influenza B virus. In addition, the Alere™ i was very rapid (15 minutes or less) and extremely easy to use. Conclusions: The Alere™ i test provided a good correlation compared to the real-time PCR test for the diagnosis of influenza. Since this method can be performed in minutes, it allows immediate, accurate clinical decisions to prescribe appropriate antiviral treatment or isolation of patients. [ABSTRACT FROM AUTHOR]

A multiparametric system able to classify red and white wines according to the grape varieties and for analysing some specific parameters is presented. The system, known as hybrid electronic tongue, consists of an array of electrochemical microsensors and a colorimetric optofluidic system. The array of electrochemical sensors is composed of six ISFETs based sensors, a conductivity sensor, a redox potential sensor and two amperometric electrodes, an Au microelectrode and a microelectrode for sensing electrochemical oxygen demand. The optofluidic system is entirely fabricated in polymer technology and comprises a hollow structure, air mirrors, microlenses and self-alignment structures. The data obtained from these sensors has been treated with multivariate advanced tools; Principal Component Analysis (PCA), for the patterning recognition and classification of wine samples, and Partial-Least Squares (PLS) regression, for quantification of several chemical and optical parameters of interest in wine quality. The results have demonstrated the utility of this system for distinguishing the samples according to the grape variety and year vintage and for quantifying several sample parameters of interest in wine quality control. [ABSTRACT FROM AUTHOR]

Objectives: Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli have been increasingly recognized in the community. The aim of this study was to determine the prevalence, types of ESBLs and risk factors for community-onset ESBL-producing E. coli in urinary tract infections (UTIs).Methods: Adults with community-onset UTIs due to ESBL-producing E. coli (cases) and non-ESBL-producing E. coli (controls) were identified through records of the clinical microbiology laboratory of the hospital. Two different periods were studied: from January 2000 to January 2001 and from October to December 2003. Controls were matched in a 3:1 ratio to case patients according to age, sex, date of isolation and residence in a long-term care facility. Potential risk factors were recorded. Isoelectric focusing as well as PCR and DNA sequencing were used to characterize the blaTEM, blaSHV and blaCTX-M genes. A possible clonal relationship among the strains was determined by repetitive extragenic palindromic sequence PCR.Results: The prevalence of infection due to ESBL-producing E. coli increased from 0.47% in 2000 to 1.7% in 2003 (P < 0.001). Community-onset ESBL-producing E. coli infection shifted from 50% in the first period to 79.5% in 2003 (P < 0.001). Nineteen cases and 55 matched controls of community-onset ESBL-producing E. coli UTI were included. ESBL-producing E. coli strains were clonally unrelated. On univariate analysis, genitourinary pathology (P < 0.03), previous bacterial infection (P = 0.01), intravenous antibiotic treatment (P = 0.01), hospitalization in the previous 12 months (P = 0.04) and previous exposure to oral second-generation cephalosporins (P < 0.05) were associated with community-onset infection due to ESBL-producing E. coli. In our regression model, only previous exposure to second-generation cephalosporins was strongly associated with E. coli harbouring ESBLs (OR, 21.42; CI 95%, 5.38–85.22; P < 0.05). In the first period, only TEM- and SHV-derived ESBLs were identified. The enzymes were characterized as members of the TEM group (60%), SHV group (16%) and CTX-M group (24%).Conclusions: We detected a marked increase in infections due to ESBL-producing E. coli, especially in the community, in the periods studied. Only previous exposure to the oxyimino cephalosporin cefuroxime, and not to ciprofloxacin, aminoglycosides or third-generation cephalosporins, was predictive of an ESBL-producing E. coli community-onset infection in our area. The emergence of the CTX-M type of β-lactamase in E. coli follows closely the spread of ESBLs in community isolates. [ABSTRACT FROM AUTHOR]

Presents information on a study which investigated the combined effect of ultraviolet radiation and turbulent mixing on chemistry in a cloud-topped boundary layer. Description of the model; Explanation on the numerical simulation; Role of chemistry on the exchange flux; Conclusions.

Provides information on the use of an archetype of turbulent reactions flowed to study the reactions zones and to obtain a description of the turbulent control of convective chemical reactions. Information on the problem formulation; Detailed information on the reaction rate limited by turbulence; Conclusions reached.

: Objectives To select rifaximin-resistant mutants of Escherichia coli and to establish the frequency of mutation, cross-resistance with other antimicrobial agents and the stability of the mutants obtained. : Methods Four E. coli isolates [two enteroaggregative E. coli (EAEC) and two enterotoxigenic E. coli (ETEC)] were used to obtain rifaximin-resistant mutants. The frequency of mutation in the presence of rifaximin, rifampicin and ciprofloxacin was established by growth on plates containing serial dilutions of antibiotic above the bacterial MIC. To determine the stability of rifaximin resistance, 28 selected resistant mutants were grown for 20 consecutive cultures on antibiotic-free plates. Every 10 days, the MICs of rifaximin, chloramphenicol, nalidixic acid and ciprofloxacin were established. : Results The frequency of mutation in the presence of rifaximin ranged between 5.7 × 10−7 and 1.6 × 10−6 in the case of the ETEC isolates, and between 2.0 × 10−8 and 9.3 × 10−8 in the case of the EAEC isolates; the frequency of mutation in the presence of rifampicin was in the order of 10−8 and no mutant in the presence of ciprofloxacin was obtained. Twenty-six out of 28 selected mutants exhibited resistance levels around or higher than 256 mg/L. In all cases, the resistance was stable, and no reversion towards the original parental MIC was observed. In no case was the MIC of chloramphenicol, nalidixic acid or ciprofloxacin affected. : Conclusions Rifaximin has a low level of resistance selection, although it may select stable highly resistant mutants in a single step. Periodical surveillance of the levels of rifaximin resistance is required to detect the possible appearance of rifaximin-resistant clinical isolates. Further studies to characterize in-depth the mechanisms of stable resistance to rifaximin are necessary. [ABSTRACT FROM AUTHOR]

Acinetobacter baumannii is an opportunistic pathogen, causing infections mainly in patients in intensive care units where the extensive use of antimicrobial agents can select for the emergence of multiresistant strains. In fact, since strains resistant to all antimicrobial agents have been reported, A. baumannii is considered the paradigm of multiresistant bacteria. Both acquired and intrinsic resistance can contribute to multiresistance. The ability to acquire multidrug resistance can be due to either the acquisition of genetic elements carrying multiple resistant determinants or mutations affecting the expression of porins and/or efflux pump(s), which can affect unrelated antimicrobial agents. Meanwhile, intrinsic resistance can be generated by the interplay of decreased permeability and constitutive expression of active efflux systems and it too can affect unrelated antimicrobial agents. This review is focused on the current knowledge of porins and efflux pump(s) in this microorganism. [ABSTRACT FROM AUTHOR]