Developmental toxicity of bisphenol A diglycidyl ether (epoxide resin badge) during the early life cycle of a native amphibian species

Bisphenol A diglycidyl ether (BADGE) is used in packaging materials, in epoxy adhesives, and as an additive for plastics, but it is also a potential industrial wastewater contaminant. The aim of the present study was to evaluate the adverse effects of BADGE on Rhinella arenarum by means of standardized bioassays at embryo–larval development. The results showed that BADGE was more toxic to embryos than to larvae at all exposure times. At acute exposure, lethality rates of embryos exposed to concentrations of 0.0005 mg/L BADGE and greater were significantly higher than rates in the vehicle control, whereas lethality rates of larvae were significantly higher in concentrations of 10 mg/L BADGE and greater. The toxicity then increased significantly, with 96‐h median lethal concentrations (LC50s) of 0.13 mg/L and 6.9 mg/L BADGE for embryos and larvae, respectively. By the end of the chronic period, the 336‐h LC50s were 0.04 mg/L and 2.2 mg/L BADGE for embryos and larvae, respectively. This differential sensitivity was also ascertained by the 24‐h pulse exposure experiments, in which embryos showed a stage‐dependent toxicity, with blastula being the most sensitive stage and S.23 the most resistant. The most important sublethal effects in embryos were cell dissociation and delayed development, whereas the main abnormalities observed in larvae related to neurotoxicity, as scare response to stimuli and narcotic effect.Fil: Hutler Wolkowicz, Ianina Ruth. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Svartz, Gabriela Veronica. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Aronzon, Carolina Mariel. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Perez Coll, Cristina Silvia. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Bolivian Quinoa in the context of globalization

The Bolivian quinoa has transformed from being a domestic food supply to being introduced to the global market. This transformation of the market has contributed to several social changes in the local society in the Altiplano, Bolivia, where quinoa has an ancient history of cultivation and consumption. By examining what determinant actors and underlying incitements that have contributed to the introduction of Bolivian quinoa to the global market, as well as to what extent it has led to social change, the concept of globalization is scrutinized. The study is conducted through a qualitative literature review of both academic articles and news from daily media of Bolivian and international origin. Material from the actors operating at the Bolivian quinoa arena are also included. The interpretation of theories considering globalization and the perception of local agency in comparison to global forces are conducted in the aim of understand the phenomenon. The findings of the study shows how globalization affects the local population and society in different directions dependent on the amount of connectedness to other places that is obtained. In the initial phase when a local commodity is introduced to the global market it is shown that the local agency is determinant on global forces and the local inherits dependency and vulnerability towards the global. When the connectedness to other places increases and stabilizes, it is possible to see how the local agency strengthens in the context of globalization

Generalized QR factorization and its applications

AbstractThe purpose of this paper is to reintroduce the generalized QR factorization with or without pivoting of two matrices A and B having the same number of rows. When B is square and nonsingular, the factorization implicity gives the orthogonal factorization of B−1A. Continuing the work of Paige and Hammarling, we discuss the different forms of the factorization from the point of view of general-purpose software development. In addition, we demonstrate the applications of the GQR factorization in solving the linear equality-constrained least-squares problem and the generalized linear regression problem, and in estimating the conditioning of these problems

Interest Rate Sensitivity of Real Estate Companies Income Statements

Title: Interest Rate Sensitivity of Real Estate Companies’ Income Statements - A Study on the Swedish Market in a Low Rate Environment Seminar date: 11th of January 2018 Course: FEKH89, Bachelor Degree Project in Financial Management, Undergraduate Level Authors: Karl Ågren, Samuel Hammarling and Sebastian Lindeborg Advisor: Anamaria Cociorva Key words: Real estate companies, repo rate, income statement sensitivity, pricing of debt, mixed methods research Purpose: The purpose of this study is to empirically investigate the sensitivity of Swedish real estate companies’ income statements towards a 100 basis point increase in the Riksbank’s repo rate. Methodology: A mixed methods research approach is employed. Qualitative research and theory constitute the framework for this study, to later be validated against the findings from three multiple regressions. Theoretical perspectives: Robert C. Merton’s theory of pricing corporate debt is, together with the findings of this study’s qualitative research, used as framework for this study. Empirical foundation: The qualitative research of this study consists of semi-structured interviews with six market experts. The quantitative research is constituted by company data and macro data: The company data includes a sample of ten companies over a ten year period, amounting to 100 firm-years. The macro data constitutes 521 observations over a ten year period. Conclusions: The study can confirm the sensitivity of Swedish real estate companies’ income statement towards changes in the Riksbank’s repo rate. The findings imply that two items are affected, interest expenses and revaluation of properties. A hypothetical 100 basis point increase in repo rate implies, according to the results, a 212 basis point decrease in revaluation of properties and a 40 basis point increase in interest expenses. This study’s focus on income statements complements previous literature that largely focuses on real estate companies’ returns and probability of default. Furthermore, the study investigates the effects of interest rates in the current unique low rate environment in Sweden, strengthening the research on the effects of low central bank rates

Stochastic effects in autoimmune dynamics

Among various possible causes of autoimmune disease, an important role is played by infections that can result in a breakdown of immune tolerance, primarily through the mechanism of ``molecular mimicry". In this paper we propose and analyse a stochastic model of immune response to a viral infection and subsequent autoimmunity, with account for the populations of T cells with different activation thresholds, regulatory T cells, and cytokines. We show analytically and numerically how stochasticity can result in sustained oscillations around deterministically stable steady states, and we also investigate stochastic dynamics in the regime of bi-stability. These results provide a possible explanation for experimentally observed variations in the progression of autoimmune disease. Computations of the variance of stochastic fluctuations provide practically important insights into how the size of these fluctuations depends on various biological parameters, and this also gives a headway for comparison with experimental data on variation in the observed numbers of T cells and organ cells affected by infection

A bootstrap method for sum-of-poles approximations

A bootstrap method is presented for finding efficient sum-of-poles approximations of causal functions. The method is based on a recursive application of the nonlinear least squares optimization scheme developed in (Alpert et al. in SIAM J. Numer. Anal. 37:1138–1164, 2000), followed by the balanced truncation method for model reduction in computational control theory as a final optimization step. The method is expected to be useful for a fairly large class of causal functions encountered in engineering and applied physics. The performance of the method and its application to computational physics are illustrated via several numerical examples

Exploring diffrent design spaces - VR as a tool during building design

During the design process of a building different medias are often used to depict the design. Traditional media, especially 2D requires high spatial skill and cognitive demand on the designers. For inexperienced designers, this process can be demanding, be difficult and can cause potential biased designperceptions that are significantly different from the reality. However, studies have also shown that different media and representation facilitates different cognitive reasoning processes about the design. Immersive Virtual Reality (VR) is assumed to give another level of understanding and perception of design space from an egocentric perception than 2D plan drawings or bird-eye views, which have been argued to provide opportunities for better pattern and object recognition that is suitable when studying spatial organization in an allocentric reasoning process. This paper investigates, the different design medias and spatial space explorations further, by studying how students used the different representations and medias (e.g. sketches, 3d-models and VR) during their design process. By combining and using both of these two design space representations, (e.g. egocentric and allocentric) in the design process, it gives a possibility to achieve a more developed design outcome. The methods used in this study were observations and un-structured interviews during the design process and a follow up questionnaire at the end of the design project. The result show, by combining and using both VR and traditional design sketching tools that it is possible to support the two design space representations together and give the designer the possibilities to explore, understand, discuss and work with the design in a more elaborate way from both an egocentric and allocentric perspective. The paper also presents in what way VR can contribute to the Evidence Based Design (EBD) criteria and how the students used different design spaces representations for design and spatial reasoning about the healthcare design of the psychiatric facility they were designing