Search

The epode of Archilochus (s. vii B. C.) composed by the ff. 172-181 S. offers a reading of the poem where the αἶνος of the eagle and the fox is presented as an exemplum of events narrated within the biographical tradition of the poet. This paper aims, on the one hand, to research how elements such as friendship, betrayal and revenge links both narratives; and, on the other hand, it intends to examine the interaction between the fable and the iambus. The analysis concludes that, in this epode, the violation of the codes of "commensality" plays a very important role in the interrelation between iambus, fable and biographical tradition. [ABSTRACT FROM AUTHOR]

This paper presents a fault detection system for photovoltaic standalone applications based on Gaussian Process Regression (GPR). The installation is a communication repeater from the Confederación Hidrográfica del Ebro (CHE), public institution which manages the hydrographic system of Aragón, Spain. Therefore, fault-tolerance is a mandatory requirement, complex to fulfill since it depends on the meteorology, the state of the batteries and the power demand. To solve it, we propose an online voltage prediction solution where GPR is applied in a real and large dataset of two years to predict the behavior of the installation up to 48 hour. The dataset captures electrical and thermal measures of the lead-acid batteries which sustain the installation. In particular, the crucial aspect to avoid failures is to determine the voltage at the end of the night, so different GPR methods are studied. Firstly, the photovoltaic standalone installation is described, along with the dataset. Then, there is an overview of GPR, emphasizing in the key aspects to deal with real and large datasets. Besides, three online recursive multistep GPR model alternatives are tailored, justifying the selection of the hyperparameters: Regular GPR, Sparse GPR and Multiple Experts (ME) GPR. An exhaustive assessment is performed, validating the results with those obtained by Long Short-Term Memory (LSTM) and Nonlinear Autoregressive Exogenous Model (NARX) networks. A maximum error of 127 mV and 308 mV at the end of the night with Sparse and ME, respectively, corroborates GPR as a promising tool. [ABSTRACT FROM AUTHOR]

This article describes a comprehensive testing method for the thermal calibration of the Thermal InfraRed Sensor (TIRS) onboard NASA's Perseverance rover. Ground-based IR detectors operating at the surface of Mars are subjected to inaccuracies caused by the inclusion of thermal gradients in their packages. To reduce such uncertainties, it is necessary to compensate for their effects. Here, details of the TIRS thermo-mechanical design and a simplified thermal mathematical model (TMM) that accounts for the presence of thermal gradients in the detector's package are provided. Then, a set of equations for the estimation and compensation of thermal gradients are proposed based on the results of the TMM. Thermal calibration tests to identify the mathematical estimators are analyzed, providing details of the test setups and highlighting their limitations and restrictions. Finally, experimental results of the calibration tests are presented, along with the uncertainty sources and potential systematic errors associated with the estimation of the gradients. The results presented here show a significant improvement in the accuracy of TIRS versus previous work, thus fulfilling of the radiometer scientific requirements set by the Mars 2020 science team. • A new thermal calibration plan for a ground-based Martian IR radiometer. • Detectors package thermal gradients estimation based on thermal modeling and tests. • Simplified test setups and differences with the Martian environment. • Performance analysis accounting for test setup uncertainties and thermal modeling. • Uncertainties meet the scientific requirements stated by the Mars 2020 science team. [ABSTRACT FROM AUTHOR]

The Mars Environmental Dynamics Analyzer (MEDA) is a suite of environmental sensors onboard NASA’s Mars 2020 mission. The Thermal InfraRed Sensor (TIRS), developed at Centro de Astrobiología of Spain, is one of the six sensors comprising MEDA, and it will measure the net thermal infrared radiation and reflected solar radiation at the surface, as well as the atmospheric and surface skin temperatures using five different channels. In combination with MEDA's other sensors, TIRS will allow the quantification of the surface energy budget and the determination of key geophysical properties of the terrain such as the albedo and thermal inertia. Here we present a general description of the TIRS, its channels scientific requirements, and the mechanical and thermal design. Then, a detailed sensor mathematical model and a sensitivity analysis to model uncertainties are described. Some characterization test results to model parameters identification are included. Finally, accuracy and resolution calculus for each channel versus operational temperature is presented. The calculus is performed based on sensitivity equations, the practical tests results and the estimated values for different uncertainty sources. [ABSTRACT FROM AUTHOR]

Abstract: Limestones used as building material are especially prone to weathering in coastal environments due to interactions between sea mist and the carbonate stone. Subtle variations of the commercial surface finishing may lead to differences in decay patterns and aesthetic properties due to salt crystallization. To explore this potentially contrasting behavior, tablets of rough and polished low-porous limestone were aged in a sea-salt spray corrosion chamber to simulate their exposure in a coastal environment. Different crystallization morphologies and relative proportions of soluble (halite) and less soluble (gypsum) salts were observed in the aged rough and polished surface samples. These morphologies are ascribed to the microtextural characteristics and the surface pore systems of the diverse (rough and polished) substrates that in turn influence fluid (saline solution) transport toward their interior, as well as the different salt solubilities interacting with the substrates. Polished surfaces exhibit little evidence of damage after the ageing test in contrast to the rough samples but do have conspicuous gypsum on the surface together with halite. The scarcity of gypsum on the rough surfaces, in addition to a more severe change in the porosity system, suggests that salts penetrate deeper when the stone surface is not polished. Potential decay induced by salt crystallization pressure is therefore minimized when the stone surface is polished. However, polished surfaces show more significant changes in luminosity and chroma after the ageing test, and so are less attractive from an aesthetic point of view. Surface finishing is thus an important feature that needs to be characterized for a better understanding of the weathering behavior of building stones used in coastal environments. [Copyright &y& Elsevier]

Emotional Expressivity, defined as the ability to express emotional states in observable behaviors, is essential for individuals healthy functioning, and was positively associated with well-being, self-esteem, life satisfaction and negatively related with diseases such as schizophrenia, depression, personality disorders and post traumatic stress disorder. To answer the need for an instrument which can evaluate this construct in a valid and reliable manner, this study explored the psychometric properties of the Emotional Expressivity Scale adapted into Spanish. For this reason, an exploratory factor analysis replicating the one-dimension solution was performed, a coefficient alpha of. 94 was obtained, gender differences with higher scores in women, and test-retest coefficients for a 4-week interval with values of .88 in women and .86 in men. Additionally, confirmatory factor analyzes were performed separately for each gender obtaining appropriate values for all fit indices, but not in men. Finally the results, scope and limitations of this paper are discussed. [ABSTRACT FROM AUTHOR]

Introduction. Pisciculture is an important activity to satisfy the alimentary necessities of a growing population. Therefore, it is necessary to develop environmentally responsible techniques. Cultivation based on periphyton is attractive, because it can feed the fish and improve the quality of the water, allowing a more efficient and cleaner system. Objective. To evaluate the effect of periphyton on some of the quality parameters of the water used for the cultivation of Nile-bocachico tilapia fish. Methodology. An experiment was performed during eight months in eighteen 90 m2 ponds with 2.7 tilapia fish per square meter and 0.7 bocachicos per square meter, with no fertilization. As a periphyton substract, vertical plastic pipes were installed (3.3 pipes/m2) and their presence or absence was an evaluated factor. Additionally, three feeding strategies were evaluated: 0 (no food), feeding with 20% of raw protein (RP) and feeding with 25% of RP. A 2x3 factorial design was used. The six treatments of the resulting factorial experiment were assigned to the experimental units based on a random design with three repetitions. Every day the dissolved oxygen, the pH, the transparency and the temperature were measured. Same thing was made every two weeks for the total ammonium, the nitrite and the phosphate. Every month, alkalinity and total thickness were measured, as well. Results. No effects of the use of substrata were found (p>0.05) for the development of periphyton on dissolved oxygen, phosphates and thickness. Effects of this factor (B) were found (p<0.05) on temperature, transparency, pH, ammonium and nitrite. Conclusion. Given the ecologic complexity of these polycultivation systems based on periphyton, the results obtained suggest the necessity of continuing the research work. [ABSTRACT FROM AUTHOR]

In the present study was evaluated the psychometric properties of the Spanish version of the German Test Anxiety Inventory in argentinean university students. Was conducted an exploratory and a confirmatory factor analysis using items parcels. The fit of three possible models was evaluated according to the theoretical background, one that supports the unidimensionality of the test anxiety, other that distinguishes the cognitive and affective components, and one that comprising four dimensions, Worry, Interference, Lack of Confidence and Emotionality as primary factors and total Test Anxiety as secondary factor. Fit indices for the last model were all adequate. Are discussed the results, the use of items parcels and the importance of multidimensional instruments of test anxiety in Spanish language. [ABSTRACT FROM AUTHOR]

Abstract: This paper analyses the spatial and temporal temperature stabilisation requirements of unchopped thermopile IR pyrometers under different temperature conditions and measurement wavelengths. Each thermopile output signal is affected differently and independently by the appearance of undesired spatial and temporal gradients in a thermopile case structure. Expressions for the ratios of thermopile sensitivity to spatial and temporal gradients versus a change in scene temperature are derived from a simplified static and dynamic thermopile thermal model that takes into account the internal structure and operation of the sensor. The ratios depend on the thermopile and the target absolute temperature, as well as the physical and optical properties of the thermopile. This knowledge may help in selecting the appropriate detector, optimising the design of pyrometer thermal control systems, or in establishing strategies to compensate for the associated uncertainty. [Copyright &y& Elsevier]

We describe the parameters that drive the design and modeling of the Rover Environmental Monitoring Station (REMS) Ground Temperature Sensor (GTS), an instrument aboard NASA's Mars Science Laboratory, and report preliminary test results. REMS GTS is a lightweight, low-power, and low cost pyrometer for measuring the Martian surface kinematic temperature. The sensor's main feature is its innovative design, based on a simple mechanical structure with no moving parts. It includes an in-flight calibration system that permits sensor recalibration when sensor sensitivity has been degraded by deposition of dust over the optics. This paper provides the first results of a GTS engineering model working in a Martian-like, extreme environment. [ABSTRACT FROM AUTHOR]

Abstract: The technical quality of two compositionally different groups of solid bricks fired between 800 and 1000°C was evaluated. Five weight percentage of fly ash was added to both groups and they were compared with similar bricks with no added fly ash. The textures of the bricks with fly ash were very similar to the textures of those without it, except that the samples with the additive contained spherical fly ash particles with diameters ranging from 0.1 to 10μm. These particles led to a reduction in the density of the bricks and a substantial improvement in their durability, with less decay being caused by salt crystallization in the pores. This is because fly ash causes a reduction in the number of micropores, the pores that make porous materials most vulnerable to salt-induced decay. Use of this additive could have practical implications as a means of recycling and for achieving cost savings in brick production. [Copyright &y& Elsevier]

Abstract: This study shows that the sandstone used in the construction of the Church of San Mateo in Tarifa (Cádiz, Spain) is highly sensitive to processes of decay because of a combination of factors that are intrinsic and extrinsic to the material. The mineralogy, texture and porous system of the sandstone and the proximity of the church to the sea all play a part in these processes. X-ray diffraction reveals that there are interstratified chlorite/smectite clays among the minerals that make up the rock. These mixed layer clays have been shown to undergo hydric expansion. This phenomenon may be accompanied and augmented by the presence of NaCl which acts as an electrolyte in osmotic swelling processes. Two varieties of sandstone were used in the construction of the church, namely grey sandstone and brown sandstone. The latter is more porous and undergoes greater hydric expansion, showing a higher degree of deterioration. Ultrasound analysis has demonstrated that both varieties are anisotropic because they contain bedding planes and are affected by the preferred orientation of the phyllosilicates in the rock. The anisotropic nature of these stones was confirmed by capillary suction tests. The capillary front reaches a relatively low height which means that when water is absorbed, the anisotropic textural properties combined with the presence of chlorite–smectite mixed layers in the sandstone result in mechanical (shear) stress between the first few centimetres of the wet stone and the dry area behind. The latter effect favours the development of flakes, so causing the decay of the ornamental stone and the church façade. [Copyright &y& Elsevier]

The changes in brick porosity upon firing (700 up to 1100 °C) and its relation to the mineralogical composition are examined. Two types of raw clay with a composition representative of that used in brick-making industry were selected to manufacture the bricks: one contains notable amounts of carbonates, with a grain size of under 1 mm, and the other is predominantly quartzitic and lacking in carbonates. We demonstrate that the presence or absence of carbonates strongly influences the porosity development and, therefore, the brick texture and physical-mechanical properties. The carbonates in the raw clay promote the formation of fissures and of pores under 1 μm in size when the bricks are fired between 800 and 1000 °C. The absence of carbonates results in a continuous reduction in porosity and a significant increase in the pore fraction with a radius (r)>1 μm as the firing temperature rises and smaller pores coalesce. Porosity and pore size distribution results obtained from the combined use of hydric tests (HT), mercury intrusion porosimetry (MIP) and digital image analysis (DIA) of scanning electron microscopy photomicrographs are compared. A clear correlation between the water absorption and drying behaviour of the bricks and the porosity plus pore size distribution is observed. DIA discloses the evolution of size, shape and connectivity of macropores (r> 1 μm) and evidences that MIP results underestimate the macropore content. Conversely, MIP gives a good estimate of the open porosity and of the distribution of pores with r<1 μm. It is concluded that the combined use of these complementary techniques helps to fully characterise the pore system of bricks. These results as well as the study of the evolution of the speed of ultrasound waves vs. time yield useful information to evaluate the bricks physical–mechanical behaviour and durability. The relevance of these findings in the conservation of historic buildings is discussed. [Copyright &y& Elsevier]

• A new radiometric and angular calibration plan for a Martian IR radiometer. • Simplified test setups and differences with Martian environmental are described. • Spectral response analysis vs. radiation incidence angle and operational temperature. • Performance analysis accounting for calibration uncertainties and set-up limitations. • Uncertainties meet the scientific requirements stated by the Mars 2020 science team. This article describes a comprehensive testing method for the radiometric and angular calibration of the Thermal InfraRed Sensor (TIRS) onboard NASA's Mars 2020 mission. First, details of the TIRS opto-mechanical design, construction aspects of the IR detectors, and an update of the mathematical model used for the calculation of sensor internal IR fluxes are provided. Then, a set of sequential calibration tests to identify the radiometer model parameters are defined. The test setups are described, highlighting their limitations and restrictions based on differences between simulated and actual Martian environmental conditions. Finally, the uncertainty sources and potential systematic errors associated with the calibration tests are quantified and compared with the radiometer scientific requirements established by the Mars 2020 science team. [ABSTRACT FROM AUTHOR]

Corbicula fluminea is an aggressive invasive species that has successfully colonized aquatic habitats worldwide, producing changes in natural environments and impacting endemic populations. As disturbed environments may favor the adaptive success of exotic species over native ones, we studied the fitness response of two freshwater bivalves, invasive C. fluminea and native Diplodon delodontus, to the presence of metals in the Parana de la Palmas River. To assess the health status of both species, we analyzed morphological and histological alterations in the digestive gland and their relation to metal concentrations in this organ and in the water. Water and specimens sampling took place in the first section of the delta of the Parana River in June and September. Most metal concentrations increased in the river, although in the digestive gland only iron in D. delodontus and nickel and zinc in C. fluminea increased seasonally. Digestive gland factor and hepatosomatic index indicated higher values in C. fluminea in both periods. Despite histological analysis showing a decrease in atrophic tubules frequency in both species, which was followed by histomorphometric parameters of the epithelium and lumen of the digestive tubules, C. fluminea exhibited a greater physiological capacity for metal metabolism and recovery. These results suggest that the physiological characteristics of the Asian clam C. fluminea, combined with its reproductive efficiency and broad dispersal capacities, could explain its invasive dispersal competence over the D. delodontus in the disturbed environmental conditions observed in the Parana de las Palmas River. [ABSTRACT FROM AUTHOR]

This research examines fired clay bricks made with waste pomace from the wine industry as an additive in brick production. To this end, we analyse and discuss the chemical, mineralogical, textural and physical-mechanical behaviour of fired bricks made with three concentrations of wine pomace (2.5, 5 and 10 wt%) and at three different firing temperatures (800, 950 and 1100 °C) and evaluate their durability to salt crystallization. Variations in colour were also examined. The firing process resulted in the decomposition of phyllosilicates and carbonates, the crystallization of Fe oxides and the appearance of high-temperature Ca- (and Mg-) silicates phases such as gehlenite, wollastonite, anorthite and diopside. The bricks made with added wine pomace had very similar mineralogy to the control samples made without it. The bricks made with added wine pomace were lighter than the control samples and underwent less linear shrinkage during the drying process. Particles in the wine pomace were consumed during firing, leading to the appearance of voids. The bricks made with this additive had higher levels of water absorption and poorer mechanical strength. The greatest colour differences were detected after increasing the amount of waste, which generally resulted in yellower bricks. The increase in firing temperature resulted in an improvement in mechanical resistance regardless of the composition of the bricks. However, bricks fired at 1100 °C made without additive are more resistant to damage caused by salts than those made with wine pomace. [Display omitted] • The reuse of wine pomace reduces the quantity of clayey material in the production of bricks. • The addition of wine pomace augments the size and number of pores in the bricks. • Bricks with wine pomace are suitable for use as lightweight materials in the construction industry. • The addition of wine pomace modifies the lightness and chromatism of bricks, not the mineralogy. [ABSTRACT FROM AUTHOR]

Axial spondyloarthritis (axSpA) comprises a spectrum of chronic inflammatory manifestations affecting the axial skeleton and represents a challenge for diagnosis and treatment. Our objective was to generate a set of evidence-based recommendations for the management of axSpA for physicians, health professionals, rheumatologists and policy decision makers in Pan American League of Associations for Rheumatology (PANLAR) countries. Grading of Recommendations, Assessment, Development and Evaluation-ADOLOPMENT methodology was used to adapt existing recommendations after performing an independent systematic search and synthesis of the literature to update the evidence. A working group consisting of rheumatologists, epidemiologists and patient representatives from countries within the Americas prioritized 13 topics relevant to the context of these countries for the management of axSpA. This Evidence-Based Guideline article reports 13 recommendations addressing therapeutic targets, the use of NSAIDs and glucocorticoids, treatment with DMARDs (including conventional synthetic, biologic and targeted synthetic DMARDs), therapeutic failure, optimization of the use of biologic DMARDs, the use of drugs for extra-musculoskeletal manifestations of axSpA, non-pharmacological interventions and the follow-up of patients with axSpA. This Evidence-Based Guideline presents the first Pan American League of Associations for Rheumatology recommendations for the management of axial spondyloarthritis, addressing therapeutic targets, the use of pharmacological and non-pharmacological interventions and monitoring of patients. [ABSTRACT FROM AUTHOR]

The article discusses that Despite the importance of sand and dust to Mars geomorphology, weather, and exploration, the processes that move sand and that raise dust to maintain Mars' ubiquitous dust haze and to produce dust storms have not been quantified as the missions lack either the necessary sensors or a sufficiently active aeolian environment.

Abstract: Bricks proceeding from one of the bastions of the Riga medieval defence wall were studied. Two main type of bricks were identified: one rich in quartz and red coloured and the other with a calcium silicate phase and yellow coloured. The survey of the bastion reveals a partial deterioration of the bricks. It was observed that differences in mineralogy and texture of calcareous and non-calcareous bricks were correlated with their behaviour in hydric and weathering tests. Data from powder X-ray diffraction (presence of high-temperature mineral phase in yellow bricks), optical microscopy (vitrification in yellow bricks), Field Emission Scanning Electron Microscope (development of secondary bubbles due to extensive melting in yellow bricks) and ultrasounds measurements (lower velocity in red bricks) allow to deduce that yellow bricks were fired at a higher temperature than the red ones. The study of the pore system revealed a bad interconnection among pores in yellow bricks (hydric data) since melt isolated the pores and filled the smallest, whereas large pores increased in size (porosimetric data). As a consequence, considering the climatic conditions of the region, yellow bricks are the materials most subjected to environmental alteration. It is in agreement with the freeze–thaw test results. Finally, low contamination of the bricks with water-soluble salts in situ leads to exclude salt-caused decay process. The relevance of these results in the conservation of Cultural Heritage is discussed. [Copyright &y& Elsevier]