Miracle-dz/UniFAR-FTUs huggingface dataset:
Análise microestrutural e das propriedades mecânicas e de durabilidade de argamassas e concretos com isoladores elétricos de porcelana

Pesquisas para utilizacao de materiais reciclados e/ou inserviveis da construcao civil em seus insumos, concretos e argamassas, e pratica recorrente ha seis decadas no mundo. No Brasil este uso vem ganhando destaque a cerca de vinte anos principalmente com os entulhos de construcao e da cerâmica vermelha. Ha uma lacuna a ser preenchida pela cerâmica branca, em especial pelos isoladores eletricos de porcelana, pois seu passivo nacional anual e de 25.000 toneladas proveniente sobretudo da substituicao de pecas obsoletas. O objetivo deste trabalho foi comprovar a utilizacao desta porcelana em concretos e argamassas atraves de sua incorporacao com diferentes graus de moagem, variando de granulometria similar ao cimento ate aos agregados, miudo e graudo, alem do estudo referente a influencia da camada de esmalte externa aos isoladores atraves de ensaios mecânicos, de durabilidade e de imagens por MEV e EDS. Para a adicao da cerâmica ao cimento nos teores em massa de 5%, 10%, 25%, 50% e 70%, nas argamassas a melhora nos resultados dos ensaios realizados comprovam sua atividade pozolânica e sua potencialidade de uso. Nos ensaios dos concretos com isoladores de porcelana substituindo o agregado miudo comum ou ambos os agregados, nos teores de 25%, 50%, 75% e 100%, os aumentos de resistencias a compressao simples e a tracao por compressao diametral obtidos foram superiores a 50% quando comparados aos valores do concreto de referencia. A influencia da camada de esmalte superficial dos isoladores nao foi constada nos ensaios realizados, sendo este mais um fator pro-utilizacao desta porcelana. As melhoras conferidas as argamassas e aos concretos, quando moldados com agregados ou aglomerantes cerâmicos em suas propriedades mecânicas e de durabilidade acompanhadas dos ensaios de imagens comprovam a utilizacao dos isoladores eletricos de porcelana nos insumos da construcao civil oferecendo com isso as industrias cerâmicas uma alternativa de uso a esta porcelana e diminuindo a producao de cimento e a extracao dos agregados Abstract
Kinetic Monte Carlo Simulations of the Grain-surface Back-diffusion Effect

Rate-equation models are a widely used and inexpensive tool for the simulation of interstellar chemistry under a range of physical conditions. However, their application to grain-surface chemical systems necessitates a number of simplifying assumptions, due to the requirement to treat only the total population of each species, using averaged rates, rather than treating each surface particle as an independent entity. While the outputs from rate-equation models are strictly limited to such population information, the inputs—in the form of the averaged rates that control the time-evolution of chemical populations—can be guided by the results from more exact simulation methods. Here, we examine the effects of back-diffusion, wherein particles diffusing on a surface revisit binding sites on the lattice, slowing the total reaction rate. While this effect has been studied for two-particle systems, its influence at greater surface coverage of reactants has not been explored. Results from two Monte Carlo kinetics models (one a 2D periodic lattice, the other the surface of a three-dimensionally realized grain) were used to develop a means to incorporate the grain-surface back-diffusion effect into rate-equation methods. The effects of grain size, grain morphology, and surface coverage on the magnitude of the back-diffusion effect were studied for the simple H+H reaction system. The results were fit with expressions that can be easily incorporated into astrochemical rate-equation models to accurately reproduce the effects of back-diffusion on grain-surface reaction rates. Back-diffusion reduces reaction rates by a maximum factor of around 5 for the canonical grain of ∼106 surface sites, but this falls to unity at close to full surface coverage.
Monitoring long-term ground movements and Deep Seated Gravitational Slope Deformations by InSAR time series: cases studies in Italy

We propose a multidisciplinary approach to study surface soil movements. They can be the expression of gravitative or tectonic events. The proposed method is based on the use of aerial photo analysis and SAR Interferometry (InSAR) techniques. The agreement of InSAR results and aerial photo interpretation allowed to detect and quantify the deformation patterns imputable to tectonics or gravitative causes. The study areas have been selected in some sectors of the Apennine chain.
Evidence for the submarine weathering of silicate minerals in Black Sea sediments: Possible implications for the marine Li and B cycles

The role of sediment diagenesis in the marine cycles of Li and B is poorly understood. Because Li and B are easily mobilized during burial and are consumed in authigenic clay mineral formation, their abundance in marine pore waters varies considerably. Exchange with the overlying ocean through diffusive fluxes should thus be common. Nevertheless, only a minor Li sink associated with the low‐temperature alteration of volcanic ash has been observed. We describe a low‐temperature diagenetic environment in the Black Sea dominated by the alteration of detrital plagioclase feldspars. Fluids expelled from the Odessa mud volcano in the Sorokin Trough originate from shallow (≈100–400 m deep) sediments which are poor in volcanic materials but rich in anorthite. These fluids are depleted in Na+, K+, Li+, B, and 18O and enriched in Ca2+ and Sr2+, indicating that anorthite is dissolving and authigenic clays are forming. Using a simple chemical model, we calculate the pH and the partial pressure of CO2 (PCO2) in fluids associated with this alteration process. Our results show that the pH of these fluids is up to 1.5 pH units lower than in most deep marine sediments and that PCO2 levels are up to several hundred times higher than in the atmosphere. These conditions are similar to those which favor the weathering of silicate minerals in subaerial soil environments. We propose that in Black Sea sediments enhanced organic matter preservation favors CO2 production through methanogenesis and results in a low pore water pH, compared to most deep sea sediments. As a result, silicate mineral weathering, which is a sluggish process in most marine diagenetic environments, proceeds rapidly in Black Sea sediments. There is a potential for organic matter‐rich continental shelf environments to host this type of diagenesis. Should such environments be widespread, this new Li and B sink could help balance the marine Li and Li isotope budgets but would imply an apparent imbalance in the B cycle.
Prevalence and Predictors of Geophagy among Adolescent Girls in Likuyani District of Kakamega County

Prevalence and Predictors of Geophagy among Adolescent Girls in Likuyani District of Kakamega County Geophagy is the regular and deliberate eating of soil by humans. Geophagy is a widespread practice in western Kenya. Geophagy significantly increases the risk of infestation with Ascaris, impair the absorption of micronutrients and cause micronutrient deficiency, particularly iron. It is estimated that approximately half of adolescent girls living in sub-Saharan Africa are anemic. Adverse effects of anemia range from severe morbidity to decreased physical work capacity to deficits in cognitive development and potentially school performance. The relationship between geophagy with iron status and anaemia is still obscure, it has not been clearly elucidated whether it is geophagy that causes iron deficiency, or it is iron deficiency that causes geophagy. The objective of this study was to determine the prevalence and predictors of geophagy among adolescent girls.
Agricultural management systems affect on physical, chemical and microbial soil properties

The purpose of this research was to assess the effects of replacement of native “Cerrado” vegetation (NV) into croplands on soil chemical, physical and microbial properties. This research was carried out on a farm under Rhodic Hapludox soil with different types of agricultural managements systems, and it was used a NV to compare the systems. The experimental design was set up in completely randomized with five treatments and five repetitions. The treatments adopted were several agricultural management systems as follow; NV; CS_Crop system; LS_Livestock system; ICLS-4_Integrated crop-livestock system with four years of implementation; ICLS-8_Integrated crop-livestock system with eight years of implementation. It was assessed some chemical, physical, and microbial parameters in the soil, as soil pH, P content, exchangeable cations, cation exchange capacity, base saturation, cations saturation, soil organic carbon (SOC), soil bulk density (SBD), aggregate stability, microbial biomass carbon (MBC), basal breathing, and microbial quotient. The replacement of NV to ICLS decreased SOC, MBC, soil aggregate stability and increase of SBD. The ICLS improved “Cerrado” soil fertility over time adoption. This integrated system increased the quantity of exchangeable K + and P content in “Cerrado” soil. The ICLS-8 showed soil environment nearby the NV. Even the difficulty in obtaining the same physical and microbial condition of NV, the results of this research point out quite important observations, because just no-till system is not enough to obtain improvement of soil quality and the ICLS can return the soil properties close to native “Cerrado” vegetation.
Predicting Time to Achieving Viral Load Less Than 50 Copies/ml in HIV Infected Patients on Antiretroviral Therapy: a Cohort Study

Effective HAART reduces blood viral load. This study aims to determine factors which could predict the time to achieve viral load (VL) less than 50 copies/ml in HIV-infected patients on antiretroviral therapy (ART). A bidirectional cohort study was conducted in 2007, with records of patients investigated retrospectively from 1997, and followed prospectively until 2009. The time from starting HAART to achieve VL less than 50 copies/ml date and its associated factors were determined. There were 63.5% (533/840) of HIV patients on ART. Mean age was 36.3 years (SD10.4), 77.9% were males, Chinese (73.0%), sexual route (88.4%) and 79.7% were at clinical stage 3-4 according to WHO staging. Mean CD4 and mean VL were 139.1cell/μl (SD 146.8) and 2.50 x 105 copies/ml (SD 7.82 x 105), respectively. The mean time to achieve VL less than 50 copies/ml was 12.5 months (SD 18). There were 82.7% (441) patients on triple drugs. There was a significant difference in time to achieve VL less than 50 copies/ml by status at start of ART, had opportunistic infection, CD4 at start ART less than 200 cell/ul took longer time to achieve VL less than 50 copies/ml. Significant predictors of the time to achieve VL less than 50 copies/ml was CD4 at start ART. The CD4 at start ART was significant predictors to achieve VL less
Is There a Rationale for Rebating Environmental Levies

Political pressure often exists for rebating environmental levies, particularly when incomplete regulatory coverage allegedly creates an “unlevel playing field” with other, unregulated firms or industries. This paper assesses the conditions under which rebating environmental levies is justified for the regulated sector. It combines a theoretical approach based on second-best modeling with numerical simulations aimed at determining the most sensitive parameters. We find that if an adequate tax on production can be levied in the unregulated sector, no rebate is justified for the regulated sector. Moreover, even in the case of constrained taxation in the unregulated sector, a tax rebate or a subsidy in the regulated sector is not necessarily a welfare-increasing policy. The exception occurs when the goods of the competing sectors are close substitutes. We find that these kinds of policy contraints can be quite costly in terms of welfare.
The Purposes of Students' Use of Web 2.0 Tools for Learning at the University

Continuous learning and knowledge updating are becoming an inseparable part of every society member‘s life, and a fast development of web 2.0 tools, suggests new teaching and learnin g possibilities. Web 2.0 tools can enhance student learning, enabling him/her to take a more active role. However, sometimes the possibilities, introduced by web 2.0, are not fully utilized. Research has shown that more often, students still use more traditional internet tools, such as email for communication and learning, rather than web 2.0 tools. Students tend to relate target learning to specialized learning and knowledge management environments, and not to specific web 2.0 tools. On the one hand, it has also been found out that web 2.0 tools are used by students as means of getting knowledge and information; on the other hand, the learners are not inclined to publicize or share the knowledge that they have created themselves.
Linear and nonlinear exponential stability of traveling waves for hyperbolic systems with relaxation

This paper is concerned with the linear and nonlinear exponential stability of traveling wave solutions for a system of quasi-linear hyperbolic equations with relaxation. By applying C0-semigroup theory and detailed spectral analysis, we prove the linear exponential stability of the traveling waves for the quasilinear systems and nonlinear exponential stability of the waves for semilinear systems, i.e., the Jin-Xin relaxation models, in some exponentially weighted spaces without assuming that the wave strengths are small.
Living landscapes: Muddy and vegetated floodplain effects on fluvial pattern in an incised river

Cohesive floodplain sediment and vegetation are both thought to cause meandering river patterns. Our aims are to compare the isolated and combined effects of mud and vegetation on river planform and morphodynamics in the setting of intermediate‐sized valley rivers. We use a numerical model for century‐scale simulation of flow, sediment transport and morphology coupled with riparian vegetation settlement, growth and mortality as functions of species traits on which flow resistance depends. Mud fluxes were predicted by excess shear stress relations in combination with the active layer formulation. We found that valley‐flooding water levels increase with vegetation density, causing a higher braiding intensity rather than meandering tendency. The shear stress during floods carves channels through the muddy floodplain surface. Higher mud concentration, on the other hand, increases floodplain aggradation, reduces the overbank flow frequency and ultimately causes formation of a single‐thread channel. Vegetation causes mud to deposit closer to the river channel as a levee, showing that mud sedimentation and vegetation settling mutually enhance floodplain formation. However, mud and vegetation counteract in two ways. First, vegetation enhances floodplain accretion, which ultimately increases plant desiccation for high mud concentrations. Second, vegetation increases the tendency of periodic chute cutoffs in valleys. The chute cutoffs locally reset the landscape and create new windows of opportunity for the vegetation. Surprisingly, in systems with a high mud concentration this causes hysteretic loops of vegetation cover and delayed mud deposition. Ramifications for the interpretation of Palaeozoic fluvial facies are that even rootless vegetation, capturing cohesive mud closer to the river channel to form thicker floodplain on the point bar, can enhance the tendency to meander and, under high mud supply, form stable channels. However, meandering is more unlikely in narrower valley rivers with higher vegetation density. © 2018 John Wiley & Sons, Ltd.
RESONANT SOURCE FOR THE SUPPLY OF ELECTRIC FIELD PROBE CALIBRATION SYSTEM AT FREQUENCIES BETWEEN 50 Hz AND 50 KHz

Electromagnetic environmental conditions checking and provision regarding long and short time human personal and occupational exposure is regulated by international standards. Generally, the human being is exposed mainly to the field generated by the 50 Hz low, medium and high voltage equipments or transmission lines of the electric power system but in industrial applications also higher frequencies are used in certain technological processes. This low and medium frequency electric fields have values in the range 0.5V/m 100kV/m for frequencies within 5Hz and 400kHz. Modern electric field measuring devices works on one or three axes, with software for measured data acquisition & storage and sometimes with the possibility of GPS source localization. In Romania, there are no installations for the periodical calibration of the instruments for low and medium frequency electric field measurement. The calibration in accredited foreign laboratories is expensive and the said instruments are used almost exclusively based on the certificates issued by supplier at purchasing. The paper presents an innovative calibration solution based on a double resonant source which enables field strengths up to 100 kV/m to be achieved in a wide frequency range within 50Hz and 50kHz.
Intra/inter-particle energy transfer of luminescence nanocrystals for biomedical applications

Elaborate design of energy transfer systems in luminescent nanocrystals revealed tremendous advantages in nanotechnology, especially in biosensing and drug delivery systems. Recently, upconversion nanoparticles have been discussed as promising probes as labels in biological assays and imaging. This article reviews the works performed in the recent years using quantum dot- and rare-earth doped nanoparticle-based energy transfer systems for biomedical applications.
PLACENTAL STEREOLOGY: SPANNING THE LEVELS FROM MOLECULE TO WHOLE ORGAN

Stereology can provide hard (functionally-relevant) quantitative information at different levels of 3D structural organization. My researches have applied established methods to study organ function and developed novel methods to study subcellular localization of marker probes. We have studied whole-organ function (passive diffusion) in the human placenta and quantified various processes at tissue and subcellular levels and in normal and complicated pregnancies. Fetoplacental angiogenesis and villous growth and maturation involve phased changes particularly around mid-gestation. Growth is associated with increased numbers of cells or nuclei and counts have shown that villous trophoblast continuously renews itself via cytotrophoblast (CT) proliferation and recruitment and syncytiotrophoblast (ST) differentiation and extrusion. Integration of these processes results in changes in total oxygen (O2) diffusive conductance which match the growing fetal mass. Similar processes occur during development of the mouse placenta and at least some are compromised in human pregnancies. For example: [a] in pure pre-eclampsia (PE), villous and fetoplacental vascular volumes and surfaces are similar to those seen in uncomplicated pregnancies but reduced in pure intrauterine growth restriction (IUGR) and in PE+IUGR; [b] trophoblast extrusion is accelerated in PE and IUGR but the latter exhibits reduced CT proliferation and this perturbed steady state leads to smaller trophoblast volumes and surfaces; [c] O2 diffusive conductances alter in various pregnancy complications, including IUGR and PE+IUGR; [d] fetal weight is diminished, but diffusive transport increases, in placentas from mice exposed to urban air pollution. Finally, innovations in quantitative immunoelectron microscopy (immunoEM) have produced a portfolio of methods for revealing non-random distributions of marker gold particles in different cellular compartments and for testing whether patterns shift following experimental manipulation. Recently, the methods have been extended to study tissue and cellular distributions of nanoparticles.
Earnings Structures, Informal Employment, and Self-Employment: New Evidence from Brazil, Mexico, and South Africa

We estimate the conditional earnings gap between formal and informal sectors, distinguishing between salary and self-employed workers. Rich panel datasets for Brazil, Mexico, and South Africa are assembled to define informality in a comparable way and to control for (time-invariant) unobserved heterogeneity. Estimations are conducted at different points of the conditional earnings distributions. Interesting results emerge. First, informal salary workers are systematically underpaid compared to their formal sector counterparts, in all countries and at almost all conditional quantiles. Yet penalties are very moderate in Brazil and Mexico while more substantial in South Africa, a country where legal advantages in formal employment are effective. Second, informal self-employment contributes to a more dispersed earnings distribution in all three countries. International comparisons reveal a continuum of situations reflecting historical and legal differences across countries, from very large self-employment penalties in South Africa to significant conditional earnings premia in Mexico.
Contemporary groups in the genetic evaluation of Nellore cattle using Bayesian inference

The objective of this work was to evaluate the criteria for the formation of contemporary groups (CGs) in the genetic evaluation of body weight at weaning in Nellore cattle. A total of 713,474 records from 3,066 herds located in Midwestern and Northern Brazil were used. Data were obtained from the genealogical registry of zebu breeds of the Brazilian association of zebu breeders. Data structures were defined based on the number of standard deviations (SDs) for outlier removal (±2.0, ±2.5, ±3.0, and ±3.5) and on the minimal number of animals per CG (3, 7, and 15). Genetic evaluation was performed with an animal model using Bayesian inference. Data structures with ±3.5 SDs and CG with at least 15 animals presented the highest additive genetic variance (82.65±2.93), and those with ±2.0 SDs and CG with at least 3 animals showed the lowest one (60.23±1.96). The proper formation of CGs results in better-quality data archives, allowing to obtain more trustable estimates for the genetic parameters. Better selection responses are obtained when the following criteria are adopted for the removal of outliers: 2.5, 3.0, and 3.5 standard deviations and a minimum of 15 animals per contemporary group.