Reference evapotranspiration estimate with limited weather data across a range of Mediterranean climates

The standard FAO Penman–Monteith (PM-ETo) method for computing the reference evapotranspiration (ETo), in addition to air temperature, needs data on solar radiation or sunshine duration, relative humidity and wind speed which are often lacking and/or do not respect appropriate quality requirements. Hence, in many cases, ETo has to be estimated with limited weather data using maximum and minimum temperature only. Essentially, two procedures are used when no more than temperature data are available: (i) the well-known Hargreaves–Samani equation (HS), or (ii) the PM-ETo method with weather parameters estimated from the limited available data, called PM temperature (PMT) method. The application of these temperature-based approaches often led to contradictory results for various climates and world regions. The data used in the analysis refer to 577 weather stations available through the CLIMWAT database. The results, confirmed by various statistical indicators, emphasized that: (a) in hyper-arid and arid zones, the performance of HS and PMT methods are similar, with root mean square errors (RMSEs) around 0.60–0.65 mm d 1; (b) in semi-arid to humid climates, the PMT method produced better results than HS, with RMSE smaller than 0.52 mm d 1; (c) the performance of PMT method could be improved when adopting the corrections for aridity/humidity in the estimation of the dew point temperature from minimum temperature data. The spatial elaboration of results indicated high variability of ETo estimates by different methods. Thus, a site-specific analysis using daily datasets of sufficient quality is needed for the validation and calibration of temperature methods for ETo estimate. Maps presenting indicative results on under/over estimation of ETo by both temperature methods may be useful for their more accurate application over different Mediterranean climate

Concentration of heavy metals and stand state of sesille oak (quercus petraea (matt.) Liebl.) On avala mountain (Serbia)

The research of heavy metals contents in soil and leaves of Sessile oak (Quercus petraea (Matt.) Liebl.). Moreover, the paper presents the analysis of the stand state on the Avala Mountain. The Avala area is high-grade protected natural resource located on the territory of Belgrade (Serbia) and its regime of exploitation and protection is clearly defined. It is assumed that the human factor is the primary cause of degradation of the protected areas of Avala. Therefore, the current inadequate stand composition and the impact of traffic pollution can be considered the decisive causes of degradation on mountain, as a natural area under special protection. Determining the degree of loading of soil and plants with heavy metals and the analysis of stand conditions of such valuable protected areas such as the area of Avala, are of great importance, based on the results obtained, to take appropriate timely precautionary measures, in order to preserve, improve nature conservation, the environment in general, and especially health conditions. The research of the contents of heavy metals (Pb, Ni, Fe, Zn i Mn) in soil showed the load of soil especially with Pb and Ni. In third locaction the concentration of Ni (amounting to 7.0 mu g/g) in the plants leaves is significantly higher which indicates the existance of chemical contamination of soil, before all, with this pollutant. The measured concentrations of all examined heavy metals (Pb, Ni, Zn, Mn and Fe) in the leaves of Sessile oak on Avala fall within the maximum allowed values in accordance with the legal regulations in Serbia

On the tungsten carbide synthesis for PEM fuel cell application - Problems, challenges and advantages

Fuel cell application of tungsten carbide is revisited starting with four different tungsten carbide precursors used for high temperature synthesis. It was shown that the final products greatly depend on the nature of the precursor. Using tungsten peroxide/2-propanol derived precursor almost pure WC was obtained which was subjected to further electrochemical investigation. It was shown that it is necessary to decorate WC with Pt nanoparticles in order to obtain satisfactory fuel cell performance, but catalytic activity of Pt/WC anode catalyst is not expected to overcome the activity of Pt/C. It is argued that new synthetic routes for the preparation of WC should be directed towards obtaining highly dispersed WC, that is, WC with high external surface area available for Pt deposition, rather than high specific surface area WC with large contribution of micropores having no importance when it comes to the use of WC as a catalyst support. The true benefit of the use of WC as catalyst support is found in increased CO tolerance/CO oxidation activity of WC-supported Pt catalysts. Qualitative mechanistic view on increased CO oxidation activity of Pt/WC is offered. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved

Epidemiology and outcomes of hospital-acquired bloodstream infections in intensive care unit patients: the EUROBACT-2 international cohort study

Purpose In the critically ill, hospital-acquired bloodstream infections (HA-BSI) are associated with significant mortality. Granular data are required for optimizing management, and developing guidelines and clinical trials. Methods We carried out a prospective international cohort study of adult patients (≥ 18 years of age) with HA-BSI treated in intensive care units (ICUs) between June 2019 and February 2021. Results 2600 patients from 333 ICUs in 52 countries were included. 78% HA-BSI were ICU-acquired. Median Sequential Organ Failure Assessment (SOFA) score was 8 [IQR 5; 11] at HA-BSI diagnosis. Most frequent sources of infection included pneumonia (26.7%) and intravascular catheters (26.4%). Most frequent pathogens were Gram-negative bacteria (59.0%), predominantly Klebsiella spp. (27.9%), Acinetobacter spp. (20.3%), Escherichia coli (15.8%), and Pseudomonas spp. (14.3%). Carbapenem resistance was present in 37.8%, 84.6%, 7.4%, and 33.2%, respectively. Difficult-to-treat resistance (DTR) was present in 23.5% and pan-drug resistance in 1.5%. Antimicrobial therapy was deemed adequate within 24 h for 51.5%. Antimicrobial resistance was associated with longer delays to adequate antimicrobial therapy. Source control was needed in 52.5% but not achieved in 18.2%. Mortality was 37.1%, and only 16.1% had been discharged alive from hospital by day-28. Conclusions HA-BSI was frequently caused by Gram-negative, carbapenem-resistant and DTR pathogens. Antimicrobial resistance led to delays in adequate antimicrobial therapy. Mortality was high, and at day-28 only a minority of the patients were discharged alive from the hospital. Prevention of antimicrobial resistance and focusing on adequate antimicrobial therapy and source control are important to optimize patient management and outcomes