Fluoride Release from Two High-Viscosity Glass Ionomers after Exposure to Fluoride Slurry and Varnish

The effect of brushing with different fluoride slurries on the fluoride release (FR) of different high-viscosity glass ionomer cements (GICs) was investigated. Fifty-eight discs were fabricated from two high-viscosity GICs (GC Fuji IX (F9) and 3M ESPE Ketac-fil (KF)). Five specimens from each brand were used to measure Vickers microhardness and the remaining were randomly assigned to one of four groups (n = 6) based on two-factor combinations: (1) fluoride concentration in the abrasive slurry (275 or 1250 ppm fluoride as NaF) and (2) immersion in a 22,500 ppm fluoride-containing solution. Specimens were brushed for a total of 20,000 strokes over 4 days with daily FR measurement. Data were analyzed using analysis of variance and Bonferroni tests (α = 0.05). Baseline FR and microhardness values were different between the two tested material brands. Exposure to a 22,500 ppm solution was associated with higher FR but not the exposure to 1250 ppm slurries. Brushing and immersion of glass ionomer cements in a 22,500 ppm F solution led to higher FR that was more sustained for KF. Type of the glass ionomer, progressive brushing, and fluoride varnish affected FR but not the fluoride content in the abrasive slurry

Brazil: Shadow WTO agricultural domestic support notifications

"This paper is devoted to better understanding of the Brazilian agricultural national policies towards domestic support and implications related to WTO rules. Domestic support has taken central stage in the last years and in light of a global economic crisis will play an even greater role in international trade politics. The paper focuses on Brazil and lays out the different domestic support policies used by the government. It is divided into five distinct parts for better comprehension. These parts are as follow: a synopsis of policies and recent studies; replication of official WTO support notifications; construction of consistent shadow notification; comparison and discussion of shadow notifications in relation to the WTO rules; and projected notifications through 2018. Also ethanol policies and the WTO rules were carefully analysed in order to better understand the Brazilian domestic support. Through this paper the reader will be able to have a better understanding of Brazilian agricultural domestic support policies with respect to WTO rules—a topic not well evaluated in the academic arena up to this time. A lot of scientific work has been done in the field of domestic support, but little has been done to better understand domestic support policies of specific countries in light of the WTO legal system." from authors' abstractAgricultural support, WTO Doha round, Notifications of domestic support, WTO compliance, Globalization,

Estimation of High-Resolution Evapotranspiration in Heterogeneous Environments Using Drone-Based Remote Sensing

Evapotranspiration (ET) is a key element of hydrological cycle analysis, irrigation demand, and for better allocation of water resources in the ecosystem. For successful water resources management activities, precise estimate of ET is necessary. Although several attempts have been made to achieve that, variation in temporal and spatial scales constitutes a major challenge, particularly in heterogeneous canopy environments such as vineyards, orchards, and natural areas. The advent of remote sensing information from different platforms, particularly the small unmanned aerial systems (sUAS) technology with lightweight sensors allows users to capture high-resolution data faster than traditional methods, described as “flexible in timing”. In this study, the Two Source Energy Balance Model (TSEB) along with high-resolution data from sUAS were used to bridge the gap in ET issues related to spatial and temporal scales. Over homogeneous vegetation surfaces, relatively low spatial resolution information derived from Landsat (e.g., 30 m) might be appropriate for ET estimate, which can capture differences between fields. However, in agricultural landscapes with presence of vegetation rows and interrows, the homogeneity is less likely to be met and the ideal conditions may be difficult to identify. For most agricultural settings, row spacing can vary within a field (vineyards and orchards), making the agricultural landscape less homogenous. This leads to a key question related to how the contextual spatial domain/model grid size could influence the estimation of surface fluxes in canopy environments such as vineyards. Furthermore, temporal upscaling of instantaneous ET at daily or longer time scales is of great practical importance in managing water resources. While remote sensing-based ET models are promising tools to estimate instantaneous ET, additional models are needed to scale up the estimated or modeled instantaneous ET to daily values. Reliable and precise daily ET (ETd) estimation is essential for growers and water resources managers to understand the diurnal and seasonal variation in ET. In response to this issue, different existing extrapolation/upscaling daily ET (ETd) models were assessed using eddy covariance (EC) and sUAS measurements. On the other hand, ET estimation over semi-arid naturally vegetated regions becomes an issue due to high heterogeneity in such environments where vegetation tends to be randomly distributed over the land surface. This reflects the conditions of natural vegetation in river corridors. While significant efforts were made to estimate ET at agricultural landscapes, accurate spatial information of ET over riparian ecosystems is still challenging due to various species associated with variable amounts of bare soil and surface water. To achieve this, the TSEB model with high-resolution remote sensing data from sUAS were used to characterize the spatial heterogeneity and calculate the ET over a natural environment that features arid climate and various vegetation types at the San Rafael River corridor

Kinetic Studies on Thermal Degradation of Nonwood Plants

Thermal analysis of nonwood plants (bagasse, rice straw, and rice hulls) was carried by using differential thermal (DT) and thermogravimetric (TG) analysis under oxidizing and inert atmospheres. Degradation patterns were different, depending on the kind of material and on the pyrolytic atmosphere. Thermal curves of rice straw and hulls were very similar, but bagasse showed a different curve. Degradation of bagasse is similar to hardwood. The rate of thermal degradation of nonwood plants is faster than wood because of their porous structure. Kinetic studies were based on weight loss obtained from TG analysis. A dual mechanism concept, similar to wood, was found for nonwood plants. Two values of activation energy were obtained with a transition temperature at 335 C. Rice straw and hulls have low values of activation energy due to their porous structure and presence of high percentage of silica, while activation energies of bagasse are close to that of hardwood. The presence of inorganic impurities in the cellulosic material has an effect on the kinetics of thermal decomposition

Automated dental identification: A micro-macro decision-making approach

Identification of deceased individuals based on dental characteristics is receiving increased attention, especially with the large volume of victims encountered in mass disasters. In this work we consider three important problems in automated dental identification beyond the basic approach of tooth-to-tooth matching.;The first problem is on automatic classification of teeth into incisors, canines, premolars and molars as part of creating a data structure that guides tooth-to-tooth matching, thus avoiding illogical comparisons that inefficiently consume the limited computational resources and may also mislead the decision-making. We tackle this problem using principal component analysis and string matching techniques. We reconstruct the segmented teeth using the eigenvectors of the image subspaces of the four teeth classes, and then call the teeth classes that achieve least energy-discrepancy between the novel teeth and their approximations. We exploit teeth neighborhood rules in validating teeth-classes and hence assign each tooth a number corresponding to its location in a dental chart. Our approach achieves 82% teeth labeling accuracy based on a large test dataset of bitewing films.;Because dental radiographic films capture projections of distinct teeth; and often multiple views for each of the distinct teeth, in the second problem we look for a scheme that exploits teeth multiplicity to achieve more reliable match decisions when we compare the dental records of a subject and a candidate match. Hence, we propose a hierarchical fusion scheme that utilizes both aspects of teeth multiplicity for improving teeth-level (micro) and case-level (macro) decision-making. We achieve a genuine accept rate in excess of 85%.;In the third problem we study the performance limits of dental identification due to features capabilities. We consider two types of features used in dental identification, namely teeth contours and appearance features. We propose a methodology for determining the number of degrees of freedom possessed by a feature set, as a figure of merit, based on modeling joint distributions using copulas under less stringent assumptions on the dependence between feature dimensions. We also offer workable approximations of this approach

Two essays on financial sector performance in Latin America

This dissertation consists of two essays on financial sector performance in Latin America. These two essays complement each other so that, when placed together, they are expected to provide policymakers with guidelines on how to design appropriate financial sector reform strategies in an attempt to promote long-term economic development, and thus to attract more foreign direct investment (FDI) inflows not only for Latin American countries, but also for developing countries in general. Chapter one investigates the extent to which the short and the long-run relationship between financial development and economic growth exists in Latin America. It focuses on two major aspects of financial development that can enhance growth: stock market and banking sector. Specifically, what role does the financial sector play in the economic growth process? What effect, positive, negative or zero, has financial development exerted on economic growth? Have the stock market and banking sector development indicators jointly entered the growth regression significantly? What type of causality, uni-directional or bi-directional, exists in the finance-growth nexus? Utilizing panel data methods and applying Granger causality tests within a framework of panel cointegration and error correction model, we attempt to answer the above questions empirically and shed some light on the roles of financial development as well as other conditional variables in determination of economic growth. Chapter one recommends that the real sector of Latin American economies should be developed further in order to sustain the development of the banking sector. On the other hand, the empirical results suggest that there is considerable evidence of bi-directional causality between stock market development and economic growth when stock market development indicators are used as proxies for financial development. Based on these results, government policies designed to enhance the efficiency of the stock markets and economic growth will be mutually beneficial in Latin America and other regions at the same stage of financial development such as East Asia, Africa, and Eastern Europe. Chapter two examines the domestic and international determinants of FDI in Latin America. In particular, what factors led to the upsurge in FDI into the region? Why are some countries more successful than others in attracting FDI? Whether factors that affect FDI in developing countries affect countries in Latin America differently. Whether countries with well-developed financial markets attract more FDI inflows. Whether FDI flows to developing countries are determined by domestic and/or international factors. This chapter attempts to answer the above questions based on the experience of 14 Latin American countries from 1978 to 2007. The empirical findings in this chapter show that both domestic and international factors have been important determinants of FDI inflows to Latin America. Therefore, chapter two recommends that emphasis in the short and medium term should be focus on reforming investment regulatory framework to remove or reduce FDI restrictions, implementing policies that promote macroeconomic economic stability, and improving the educational and physical infrastructure. While, in the long-run, more FDI can be attained by persisting support for FDI liberalization through bilateral or multilateral means, continuing of the privatization process, and implementing appropriate monetary and fiscal policies for economic reforms and international integration with the world economy, thereby improving the attractiveness of a nation as a destination for FDI. Further analyzing the relationship between FDI and financial development, the empirical findings provide supporting evidence that a well-developed financial sector can represent a source of absorptive capacity in the host country which may enable these countries to absorb the positive impact of FDI. Therefore, the evidence suggests that Latin American countries should continue to stimulate and improve financial sector development in the economy to make it more attractive for foreign investors. The Granger causality results show that the causal link between FDI and banking sector development is uni-directional, suggesting that the development of banking sector in Latin American countries can attract more FDI. We also provide evidence that the link between FDI and stock market development indicators is bi-directional. Therefore, the evidence suggests that Latin American countries should continue to stimulate and improve financial sector development in the economy to make it more attractive for foreign investors