1,151 research outputs found

    Validation of 3-day rainfall forecast at the regional scale

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    Nearly half of the natural disasters in the world are due to hydro-geomorphological hazards. Therefore, rainfall forecast is a key parameter for the implementation of landslides and flash-floods early warning systems. In this work we developed a routine in R software that enables the validation of a 3-day rainfall forecast by comparison with the daily rainfall data recorded in 101 automatic meteorological stations available in mainland Portugal. The routine integrates the pre-processing of base data, the matching between the 3-day rainfall forecast and the daily rainfall registered in the automatic meteorological stations based on sequence of days, the estimation of the difference between the forecasted and the real rainfall values and the computation of error measures, such as the bias, the mean absolute error, the mean absolute percentage error and the root mean square error. The results from the error measures, estimated for the 101 automatic meteorological stations, are then exported to an excel file. The routine is implemented for mainland Portugal and tested using data from February 2015, however, the spatial and temporal data can be easily updated for other regions

    Validation of 3-day rainfall forecast at the regional scale

    Get PDF
    Nearly half of the natural disasters in the world are due to hydro-geomorphological hazards. Therefore, rainfall forecast is a key parameter for the implementation of landslides and flash-floods early warning systems. In this work we developed a routine in R software that enables the validation of a 3-day rainfall forecast by comparison with the daily rainfall data recorded in 101 automatic meteorological stations available in mainland Portugal. The routine integrates the pre-processing of base data, the matching between the 3-day rainfall forecast and the daily rainfall registered in the automatic meteorological stations based on sequence of days, the estimation of the difference between the forecasted and the real rainfall values and the computation of error measures, such as the bias, the mean absolute error, the mean absolute percentage error and the root mean square error. The results from the error measures, estimated for the 101 automatic meteorological stations, are then exported to an excel file. The routine is implemented for mainland Portugal and tested using data from February 2015, however, the spatial and temporal data can be easily updated for other regions. • A routine to validate the rainfall forecast at the regional scale using R programming language is implemented. • The automated routine can be easily updated and adapted with different spatial and temporal scales

    Phosphorous nanofertilizers for Precise application in rice cultivation as an adaptation to climate change

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    Rice is the staple food of more than half of the world’s population, which is still growing. The great dependence that agriculture, and rice specially, has on fertilizers alongside extreme events that result from climatic change creates an urge for adaptation. Fertilizers are expensive, finite and a potential environmental problem. Their precise application, by the use of slow-release nanofertilizers, thus avoiding losses and consequently reducing the pressure on water resources, is one step forward in this adaptation. It can reduce costs and protect the environment while ensuring food production. Phosphorous is very important for rice, since it is involved in its flowering and root development, and its low availability to the plants constitutes a serious problem. The delivery of phosphorous through the crop cycle in the form of slow-release phosphorus nanofertilizer (Pnf) instead of the conventional annual bulk application reduces the amount of nutrients applied and increases the absorption by the crop. Combining the fertilizing effect with the use of natural stimulant compounds such as chitosan can protect the crop from diseases and increase its resilience to stress. The use of Pnf reduces the pressure on water resources and avoids imbalances in soil nutrients, thus responding to climatic change challenges and abiotic stresses.info:eu-repo/semantics/publishedVersio

    Characterization of antioxidants activity in a microfluidic channel

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    Antioxidant is the common designation for substances that have a potential action in the prevention of oxidative stress. The characterization of the reactivity of these substances has attracted the attention of many researchers, with the aim to establish correlations between the intake of antioxidants and health maintenance or to detect early stages of diseases associated with oxidative stress. The measurement of antioxidant capacity of physiological fluids (blood serum, saliva or urine) or foodstuff is currently performed by means of different methods, mostly based on spectrophotometric detection. Voltammetry has gained popularity in this context.[1] Whereas peak potentials are used to characterize the reactivity of the antioxidant, the peak currents (or the area under voltammograms) are used for the antioxidant capacity evaluation. Although voltammetric methods constitute one of the most effective means to monitor the antioxidant electron-transfer reactions, quantitative information is not directly obtained from voltammograms of antioxidants mixtures. The antioxidant capacity is usually evaluated by relative parameters defined towards a reference substance. The significance of this result is limited and cannot be translated in the effective protection degree provided by the antioxidant. In a recent work, we have proposed an analytical method for the evaluation of the reducing antioxidant capacity of antioxidants evaluated by electrolysis (RACE). [2] The oxidation of antioxidants is analyzed in large scale controlled potential electrolysis and its consumption is monitored at the anode by the current decrease. The monitored charge for the complete oxidation of active antioxidants provides a quantitative measure of their ability to eliminate a given reactive oxygen species, according to the selected potential used in the electrolysis. In order to transfer the RACE methodology to a sensor design, electrochemical microfluidic devices were built and tested. Experimental variables such as device geometry and flow rate were optimised in order to achieve a thin-layer regime in mass transport [3]. The chronoamperometric response of antioxidants was analyzed to evaluate its reducing power at selected potentials, according to the nature of the reactive oxygen species whose action is simulated. These results demonstrated the validity of the concept

    In vitro blood flow and cell-free layer in hyperbolic microchannels: visualizations and measurments

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    Red blood cells (RBCs) in microchannels has tendency to undergo axial migration due to the parabolic velocity profile, which results in a high shear stress around wall that forces the RBC to move towards the centre induced by the tank treading motion of the RBC membrane. As a result there is a formation of a cell free layer (CFL) with extremely low concentration of cells. Based on this phenomenon, several works have proposed microfluidic designs to separate the suspending physiological fluid from whole in vitro blood. This study aims to characterize the CFL in hyperbolic-shaped microchannels to separate RBCs from plasma. For this purpose, we have investigated the effect of hyperbolic contractions on the CFL by using not only different Hencky strains but also varying the series of contractions. The results show that the hyperbolic contractions with a Hencky strain of 3 and higher, substantially increase the CFL downstream of the contraction region in contrast with the microchannels with a Hencky strain of 2, where the effect is insignificant. Although, the highest CFL thickness occur at microchannels with a Hencky strain of 3.6 and 4.2 the experiments have also shown that cells blockage are more likely to occur at this kind of microchannels. Hence, the most appropriate hyperbolic-shaped microchannels to separate RBCs from plasma is the one with a Hencky strain of 3.The authors acknowledge the financial support provided by PTDC/SAU-ENB/116929/2010 and EXPL/EMS-SIS/2215/2013 from FCT (Fundação para a Ciência e a Tecnologia), COMPETE, QREN and European Union (FEDER). R.O. Rodrigues, D. Pinho and P. C. Sousa acknowledge the scholarships SFRH/BD/97658/2013, SFRH/BD/89077/2012 and SFRH/BPD/75258/2010, respectively, all attributed by FCT

    Bis(tetra­phenyl­phospho­nium) bis­[N-(2,5-dichloro­phenyl­sulfon­yl)dithio­carbimato(2−)-κ2 S,S′]platinate(II)

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    In the title salt, (C24H20P)2[Pt(C7H3Cl2NO2S3)2], the PtII ion (site symmetry ) is coordinated by two S,S′-bidentate N-(2,5-dichloro­phenyl­sulfon­yl)dithio­carbimate ligands, resulting in a slightly distorted PtS4 square-planar geometry. In the crystal, a C—H⋯O inter­action is observed, as well as electrostatic attraction between the oppositely charged ions

    Calcium-dependent mitochondrial permeability transition is augmented in the kidney of Goto-Kakizaki diabetic rat

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    Renal disease associated with diabetes mellitus is a major problem among diabetic patients. The role of mitochondria in the pathogenesis of diabetes has received a large amount of attention in the last years, but many aspects of this subject are still poorly understood. In the present study, we studied the susceptibility of the mitochondrial permeability transition (MPT) on kidney mitochondria from the Goto-Kakizaki (GK) rat, an animal model featuring physiological and pathological alterations characteristic of type 2 diabetes.Kidney mitochondria were isolated by differential centrifugations; mitochondrial electric transmembrane potential and calcium loading capacity were evaluated with a TPP+-selective electrode and with a calcium-sensitive fluorescent probe. Coenzyme Q9, Q10 and vitamin E were evaluated by high-performance liquid chromatography (HPLC).Kidney mitochondria from the diabetic animals had an increased susceptibility to the induction of the MPT by calcium. We observed a loss of calcium-loading capacity and a higher calcium-induced mitochondrial depolarization. Vitamin E and coenzyme Q9 were also increased in kidney mitochondria from GK rats.The results show an enhanced MPT activation in kidney mitochondria from GK rats, which lead us to suggest that this condition may be one major alteration triggered by chronic diabetes in kidney cells, ultimately leading to cell dysfunction. Copyright © 2004 John Wiley & Sons, Ltd

    Electrochemical miRNA-34a-based biosensor for the diagnosis of Alzheimer’s disease

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    Alzheimer's disease (AD) is the most common dementia type and a leading cause of death and disability in the elderly. Diagnosis is expensive and invasive, urging the development of new, affordable, and less invasive diagnostic tools. The identification of changes in the expression of non-coding RNAs prompts the development of diagnostic tools to detect disease-specific blood biomarkers. Building on this idea, this work reports a novel electrochemical microRNA (miRNA) biosensor for the diagnosis of AD, based on carbon screen-printed electrodes (C-SPEs) modified with two gold nanostructures and a complementary anti-miR-34a oligonucleotide probe. This biosensor showed good target affinity, reflected on a 100 pM to 1 M linearity range and a limit of detection (LOD) of 39 pM in buffer and 94 aM in serum. Moreover, the biosensors response was not affected by serum compounds, indicating selectivity for miR-34a. The biosensor also detected miR-34a in the cell culture medium of a common AD model, stimulated with a neurotoxin to increase miR-34a secretion. Overall, the proposed biosensor makes a solid case for the introduction of a novel, inexpensive, and minimally invasive tool for the early diagnosis of AD, based on the detection of a circulating miRNA overexpressed in this pathology.This work was supported by 0624_2IQBIONEURO_6_E, 2IQBioneuro, Promotion of an R&I network in biological chemistry for the diagnosis and treatment of neurological diseases EP-INTERREG V Spain Portugal (POCTEP), and by Portuguese funds through FCT in the framework of the project PTDC/BTM-MAT/4156/2021. S.D.S acknowledges FCT (Fundação para a Ciência e a Tecnologia, I.P.) for her contract under the Norma Transitória – DL57/2016/CP/CP1360/CT0013.info:eu-repo/semantics/publishedVersio
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