Columnar joints in the Patino Formation sandstones, Eastern Paraguay: a dynamic interaction between dyke intrusion, quartz dissolution and cooling-induced fractures

The Patino Formation sandstones, which crop out in Aregua neighborhood in Eastern Paraguay and show columnar joints near the contact zone with a nephelinite dyke, have as their main characteristics the high proportion of syntaxial quartz overgrowth and a porosity originated from different processes, initially by dissolution and later by partial filling and fracturing. Features like the presence of floating grains in the syntaxial cement, the transitional interpenetrative contact between the silica-rich cement and grains as well as the intense fracture porosity are strong indications that the cement has been formed by dissolution and reprecipitation of quartz from the framework under the effect of thermal expansion followed by rapid contraction. The increase of the silica-rich cement towards the dyke in association with the orthogonal disposition of the columns relative to dyke walls are indicative that the igneous body may represent the main heat source for the interstitial aqueous solutions previously existing in the sediments. At macroscopic scale, the increasing of internal tensions in the sandstones is responsible for the nucleation of polygons, leading to the individualization of prisms, which are interconnected by a system of joints, formed firstly on isotherm surfaces of low temperature and later on successive adjacent planes towards the dyke heat source.

U-curve: A branch-and-bound optimization algorithm for U-shaped cost functions on Boolean lattices applied to the feature selection problem

This paper presents the formulation of a combinatorial optimization problem with the following characteristics: (i) the search space is the power set of a finite set structured as a Boolean lattice; (ii) the cost function forms a U-shaped curve when applied to any lattice chain. This formulation applies for feature selection in the context of pattern recognition. The known approaches for this problem are branch-and-bound algorithms and heuristics that explore partially the search space. Branch-and-bound algorithms are equivalent to the full search, while heuristics are not. This paper presents a branch-and-bound algorithm that differs from the others known by exploring the lattice structure and the U-shaped chain curves of the search space. The main contribution of this paper is the architecture of this algorithm that is based on the representation and exploration of the search space by new lattice properties proven here. Several experiments, with well known public data, indicate the superiority of the proposed method to the sequential floating forward selection (SFFS), which is a popular heuristic that gives good results in very short computational time. In all experiments, the proposed method got better or equal results in similar or even smaller computational time. (C) 2009 Elsevier Ltd. All rights reserved.

Generating segmented meshes from textured color images

This paper presents a new framework for generating triangular meshes from textured color images. The proposed framework combines a texture classification technique, called W-operator, with Imesh, a method originally conceived to generate simplicial meshes from gray scale images. An extension of W-operators to handle textured color images is proposed, which employs a combination of RGB and HSV channels and Sequential Floating Forward Search guided by mean conditional entropy criterion to extract features from the training data. The W-operator is built into the local error estimation used by Imesh to choose the mesh vertices. Furthermore, the W-operator also enables to assign a label to the triangles during the mesh construction, thus allowing to obtain a segmented mesh at the end of the process. The presented results show that the combination of W-operators with Imesh gives rise to a texture classification-based triangle mesh generation framework that outperforms pixel based methods. Crown Copyright (C) 2009 Published by Elsevier Inc. All rights reserved.

Flow injection amperometric determination of hydrogen peroxide in household commercial products with a ruthenium oxide hexacyanoferrate modified electrode

Hydrogen peroxide was determined in oral antiseptic and bleach samples using a flow-injection system with amperometric detection. A glassy carbon electrode modified by electrochemical deposition of ruthenium oxide hexacyanoferrate was used as working electrode and a homemade Ag/AgCl (saturated KCl) electrode and a platinum wire were used as reference and counter electrodes, respectively. The electrocatalytic reduction process allowed the determination of hydrogen peroxide at 0.0 V. A linear relationship between the cathodic peak current and concentration of hydrogen peroxide was obtained in the range 10-5000 mu mol L(-1) with detection and quantification limits of 1.7 (S/N = 3) and 5.9 (S/N = 10) mu mol L(-1), respectively. The repeatability of the method was evaluated using a 500 mu mol L(-1) hydrogen peroxide solution, the value obtained being 1.6% (n = 14). A sampling rate of 112 samples h(-1) was achieved at optimised conditions. The method was employed for the quantification of hydrogen peroxide in two commercial samples and the results were in agreement with those obtained by using a recommended procedure.

Cellulose swelling by protic solvents: which properties of the biopolymer and the solvent matter?

The question posed in the title has been addressed by studying the swelling of celluloses at 20 C by twenty protic solvents, including water; linear- and branched-chain aliphatic alcohols; unsaturated aliphatic alcohols, and alkoxyalcohols. The biopolymers investigated included microcrystalline cellulose, MC, native and never-dried mercerized cotton cellulose, cotton and M-cotton, and native and never-dried mercerized eucalyptus cellulose, eucalyptus and M-eucalyptus, respectively. In most cases, better correlations with the physico-chemical properties of the solvents were obtained when the swelling was expressed as number of moles of solvent/anhydroglucose unit, nSw, rather than as % increase in sample weight. The descriptors employed in these correlations included, where available, Hildebrand`s solubility parameters, Gutmann`s acceptor and donor numbers, solvent molar volume, V(S), as well as solvatochromic parameters. The latter, employed for the first time for correlating the swelling of biopolymers, included empirical solvent polarity, E(T)(30), solvent ""acidity"", alpha(S), ""basicity"", beta(S), and dipolarity/polarizability, pi(S)*, respectively. Small regression coefficients and large sums of the squares of the residues were obtained when values of nSw were correlated with two solvent parameters. Much better correlations were obtained with three solvent parameters. The most statistically significant descriptor in the correlation equation depends on the cellulose, being pi(S)* for MC, cotton, and eucalyptus, and V(S) for M-cotton and M-eucalyptus. The best correlations were obtained with the same set of four parameters for all celluloses, namely, solvent pKa (or alpha(S)) beta(S), pi(S)*, and V(S), respectively. These results indicate that the supra-molecular structure of the biopolymer, in particular the average sizes of crystallites and micro-pores, and the presence of its chains in parallel (cellulose I) or anti-parallel (cellulose II) arrangements control its swelling. At least for the present biopolymer/solvent systems, use of solvatochromic parameters is a superior alternative to Hildebrand`s solubility parameters and/or Gutmann`s acceptor and donor numbers. The relevance of these results to the accessibility of the hydroxyl groups of cellulose, hence to its reactivity, is briefly discussed.

Print quality study of newsprint : Further development of the laboratoryoffset press at PAPRO

A laboratory offset press has been developed over the last five years at PAPRO for testing print qualityon newsprint, as at present, there is no good way for the mills to test this issue. In this project a comparisonhas been made between a laboratory offset press and a commercial press to see if the laboratoryoffset press can be used as a reliable test method or if a further development is needed.To evaluate the method, similar papers have been printed in both presses and compared using imageanalysis techniques. All together eighteen samples were tested which is enough to give comparableresults. The print quality showed a high variation, the values from the laboratory offset press and thecommercial press were not following the same trends. At present time the laboratory offset press needsome further development before it can be used as a reliable test method for halftone prints. Even sosome conclusions were made.The newsprint that has been used came from Norske Skog Tasman Mill (Kawerau), since the otheraim of this project was to do a repeatability study of their three existing paper machines to distinguishpossible differences in the production. The paper samples were taken from each paper machine on sixdifferent dates to give a representative result. This also gave the opportunity to compare the machinesbetween themselves. Comparison between the machines shows that the wire side gives a better andmore even result than the topside on the prints from the laboratory offset press. According to the resultfrom the commercial press the wire side shows a higher degree of variability. Samples from papermachine 2 and 3 were less variable and had the lowest standard deviation of grey level for solid areas.This suggests that newsprints from PM 2 and PM 3 give a more even print quality with a better inkcoverage.

Induktiv provning av ferritiskt rostfritt stå

The report examines the factors which may be a contributing cause to the problems that are present when ferritic stainless steel are eddy current tested in a warm condition. The work is carried out at Fagersta Stainless AB in Fagersta which manufactures stainless steel wire. In the rolling mill there is an eddy current equipment for detection of surface defects on the wire. The ferritic stainless steels cause a noise when testing and this noise complicates the detection of defects.Because of this, a study was made of how the noise related to factors such as steel grade, temperature, size and velocity. By observing the signal and with the possibilities to change the equipment settings the capability to let a signal filter reduce the noise level were evaluated. Theories about the material's physical properties have also been included, mainly the magnetic properties, electrical conductivity and the material's tendency to oxidize.Results from the tests show that a number of factors do not affect the inductive test significantly and to use a filter to reduce the noise level does not seem to be a viable option. The level of noise does not relate to the presence of superficial particles in form of oxides.The ferritic stainless steels showed some difference in noise level. Which noise level there was did match well with the steels probability for a precipitation of a second phase, and precipitation of austenite may in this case contribute to noise when using an eddy current instrument.The noise is probably due to some physical material property that varies within the thread.

Evolution of artificial defects during shape rolling

Very often defects are present in rolled products. For wire rods, defects are very deleterious since the wire rods are generally used directly in various applications. For this reason, the market nowadays requires wire rods to be completely defect-free. Any wire with defects must be rejected as scrap which is very costly for the production mill. Thus, it is very important to study the formation and evolution of defects during wire rod rolling in order to better understand and minimize the problem, at the same time improving quality of the wire rods and reducing production costs. The present work is focused on the evolution of artificial defects during rolling. Longitudinal surface defects are studied during shape rolling of an AISI M2 high speed steel and a longitudinal central inner defect is studied in an AISI 304L austenitic stainless steel during ultra-high-speed wire rod rolling. Experimental studies are carried out by rolling short rods prepared with arteficial defects. The evolution of the defects is characterised and compared to numerical analyses. The comparison shows that surface defects generally reduce quicker in the experiments than predicted by the simulations whereas a good agreement is generally obtained for the central defect.

Tribology in Metal Working

This thesis focuses on the tribological performance of tool surfaces in two steel working operations, namely wire drawing and hot rolling. In all forming operations dimensions and surface finish of the products are of utmost importance. Forming basically includes three parts – forming conditions excluded – that may be changed; work material, tool and (possibly) lubricant. In the interface between work material and tool, the conditions are very aggressive with – generally or locally – high temperatures and pressures. The surfaces will be worn in various ways and this will change the conditions in the process. Consequently, the surface finish as well as the dimensions of the formed product may change and in the end, the product will not fulfil the requirements of the customer. Therefore, research and development in regard to wear, and consequently tribology, of the forming tools is of great interest. The investigations of wire drawing dies focus on coating adhesion/cohesion, surface characteristics and material transfer onto the coated steel both in laboratory scale as well as in the wire drawing process. Results show that it in wire drawing is possible to enhance the tribological performance of drawing dies by using a lubricant together with a steel substrate coated by a polished, dual-layer coating containing both hard and friction-lowering layers. The investigations of hot rolling work rolls focus on microstructure and hardness as well as cracking- and surface characteristics in both laboratory scale and in the hot strip mill. Results show that an ideal hot work roll material should be made up of a matrix with high hardness and a large amount of complex, hard carbides evenly distributed in the microstructure. The surface failure mechanisms of work rolls are very complex involving plastic deformation, abrasive wear, adhesive wear, mechanical and thermal induced cracking, material transfer and oxidation. This knowledge may be used to develop new tools with higher wear resistance giving better performance, lower costs and lower environmental impact.

Att bli, att vara och att ha varit - om ingångar i och utgångar ur Jehovas vittnen i Sverige

Summary To become, to be and to have been: about the  Jehovah’s Witnesses The Watchtower Bible and Tract Society, in the following text referred to as the Jehovah’s Witnesses or “the organisation”, is a worldwide Christian organisation with about 6.7 million members. The organisation has many times, without any success so far, proclaimed Armageddon when they expect Jehovah to return to Earth. They interpret the Bible in their own, often very literal way, and require their members to live according to these interpretations. Among the consequences of this, members are forbidden to vote, to do military service or to receive blood transfusions. Apart from attending the three weekly meetings, members are expected to be active in missionary work, known as “publishing”. If a member fails to do a certain number of hours’ publishing, he or she risks being deprived of active membership status Sweden in general is considered to be a society where the population is not very religious. The formerly state-governed Lutheran church has lost its influence and the vast majority of ordinary Swedes do not visit church on other occasions than weddings, funerals or christenings. Expressing one’s own religious values has become somewhat of a private matter where publicity is seldom appreciated, which is contrary to the practice of the Jehovah’s Witnesses. This is one of the reasons why the Jehovah’s Witnesses are commonly perceived by average Swedes as a “suspicious” religious organisation. The aim and methods of the study This dissertation seeks to describe and investigate the entering and leaving of a highly structured and hierarchical religious community, exemplified in this case by the Jehovah’s Witnesses. What are the thoughts and aspirations of someone who is considering becoming a Jehovah’s Witness? What are the priorities and what experiences seem important when a person is going through such a process? And when this person has finally reached his or her goal of becoming a member, is it the same motivation that makes him or her stay in the organisation for longer periods of time, possibly for the rest of their lives, or does it change during the process of entering, or does this motivation change its character during the transition from entering to being a regular member? Why do some of the members change their attitude to the Jehovah’s Witnesses from rejoicing to bitterness? And how does this process of exit manifest itself? In what way is it different from the process of entry? The respondents in this study were chosen from both active members of the Jehovah’s Witnesses in Sweden and those who have left the organisation for personal reasons. Repeated interviews with ten active members of the organisation have been conducted in the course of the study and compared to equal numbers of former members. The interviews have been semi-structured to deal with questions of how a person has come into contact with the organisation; how they retrospectively experienced the process of entry; the reasons for becoming a member. Questions have also been asked about life in the organisation. The group of “exiters” have also been asked about the experience of leaving, why they wanted to leave, and how this process was started and carried out. In addition to this I have analysed a four-year diary describing the time inside and the process of leaving the organisation. This has given me an extra psychological insight into the inner experience of someone who has gone through the whole process. The analysis has been done by categorising the content of the transcribed interviews. An attempt to outline a model of an entry and exit process has been made, based on ideas and interpretations presented in the interviews. The analysis of the diary has involved thorough reading, resulting in a division of it into four different parts, where each part has been given a certain key-word, signifying the author’s emotional state when writing it. A great deal of the information about the Jehovah’s Witnesses has been collected through discussion boards on the Internet, informal talks with members and ex-members, interviews with representatives of the organisations during visits to its different offices (Bethels), such as St. Petersburg, Russia, and Brooklyn, New York, USA. The context Each organisation evolves in its own context with its own norms, roles and stories that would not survive outside it. With this as a starting point, there is a chapter dedicated to the description of the organisation’s history, structure and activities. It has been stated that the organisation’s treatment of its critical members and the strategies for recruiting new members have evolved over the years of its history. At the beginning there was an openness allowing members to be critical. As the structure of the organisation has become more rigid and formalised, the treatment of internal critics has become much less tolerated and exclusion has become a frequent option. As a rule many new members have been attracted to the organisation when (1) the day of Armageddon has been pronounced to be approaching; (2) the members of the organisation have been persecuted or threatened with persecution; and (3) the organisation has discovered a “new market”. The processes for entering and exiting How the entering processes manifest themselves depends on whether the person has been brought up in the organisation or not. A person converting as an adult has to pass six phases before being considered a Jehovah’s Witness by the organisation. These are:  Contact with the Jehovah’s Witnesses, Studying the bible with members of the organisation, Questioning, Accepting, Being active as publisher (spreading the belief), Being baptised.  For a person brought up in the organisation, the process to full membership is much shorter:   Upbringing in the organisation, Taking a stand on the belief, Being baptised. The exit process contains of seven phases:   Different levels of doubts, Testing of doubts, Turning points, Different kinds of decisions, Different steps in executing the decisions, Floating, a period of emotional and cognitive consideration of membership and its experiences, Realtive neutrality.   The process in and the process out are both slow and are accompanied with anguish and doubts. When a person is going through the process in or out of the organisation he or she experiences criticism. This is when people around the adept question the decision to continue in the process. The result of the criticism depends on where in the process the person is. If he or she is at the beginning of the process, the criticism will probably make the person insecure and the process will slow down or stop. If the criticism is pronounced in a later phase, the process will probably speed up. The norms of the organisation affect the behaviour of the members. There are techniques for inclusion that both bind members to the organisation and shield them off from the surrounding society. Examples of techniques for inclusion are the “work situation” and “closed doors”. The work situation signifies that members who do as the organisation recommends – doing simple work – often end up in the same branch of industry as many other Jehovah’s Witnesses. This often means that the person has other witnesses as workmates. If the person is unemployed or moves to another town it is easy to find a new job through connections in the organisation. Doubts and exclusions can lead to problems since they entail a risk of losing one’s job. This can also result in problems getting a new job. Jehovah’s Witnesses are not supposed to talk to excluded members, which of course mean difficulties working together. “Closed doors” means that members who do as the organisation recommends – not pursuing higher education, not engaging in civil society, working with a manual or in other way simple job, putting much time into the organisation – will, after a long life in the organisation, have problems starting a new life outside the Jehovah’s Witnesses. The language used in the organisation shows the community among the members, thus the language is one of the most important symbols. A special way of thinking is created through the language. It binds members to the organisation and sometimes it can work as a way to get back into the normative world of the organisation. Randall Collins’s (1990, 2004) thoughts about “emotional energy” have enabled an understanding of the solidarity and unity in the organisation. This also gives an understanding of the way the members treat doubting and critical members. The members who want to exit have to open up the binding/screening off. A possible way to do that is through language, to become aware of the effect the language might have. Another way is to search for emotional energy in another situation. During the exit process, shame might be of some importance. When members become aware of the shame they feel, because they perceive they are “acting a belief”, the exit process might accelerate.

Att lämna en värld : Om utgångsprocesser ur Jehovas vittnen

It is an everyday experience to realize that things do not turn out the as expected. But what if you realize that everything you have so far experienced as reality is illusion? This article is about former members of the Jehovah’s Witnesses who have had doubts about what they previously believed to be the Truth. The article also treats the exit process, from being a Jehovah’s Witness to becoming an ex-Jehovah’s Witness. The data consists of twenty qualitative interviews with ten Jehovah’s Witnesses and twenty qualitative interviews with ten former Jehovah’s Witnesses. The data also include a diary written during four years preceding an exit from the organization. The analysis was made through thematic concentration. Ontologically the analysis and the article are based on a constructionist view though it is mainly empirical with no further theoretical assessment. However, to be able to understand the results a contextual frame is sketched with two factors affecting members who make an exit. First there are tying factors that bind the person closer to the organization; these are closeness and friendship and confirmation. A secluding factor is something that secludes the member from the outside society; these factors are the work situation and »closed doors«. With high values on these factors the exit process will be more arduous. The results are presented through a process model in which different phases or steps in the exit process are described. The following steps in the process are: (1) different levels of doubts; (2) trying out doubts; (3) turning points; (4) different decisions; (5) different steps in execution; (6) floating; (7) relative neutrality. The process is defined as an altogether ambivalent and emotionally tough experience, but other parts of life may be affected as well, such as employment, social life, family life and career.

A Spatial Comparison of Short and Long Term Migration Trends in China

China’s floating population, those individuals who have migrated between counties or provinces for a period of longer than 6 months, account for 79 million individuals. If intracounty migration is also included, the number jumps to 145 million individuals or over 11% of the total population. This study examines the geographical differences in short and long term migration using ArcGIS to manipulate the spatial GIS data. The study shows that both short and long term migration (in absolute numbers) occurs more frequently near cities and in coastal regions. However, by normalizing the data by population size, the study eliminates the problems of population size on the size of the migrants. Using this normalized data, the study finds that western and northern counties have a large number of migrants present relative to the size of the population. Determining where this floating population migrates helps explain regional inequalities in employment opportunities.

Contribuição da Endotelina-1 para o tônus coronariano de seres humanos: experimentos com o antagonista dos receptores ET-A

Introdução. A endotelina-1, o mais potente vasoconstritor endógeno, atua através de dois receptores de afinidades distintas, conhecidos como ETA e ETB. Os receptores ETA estão localizados predominantemente na musculatura lisa vascular e são os principais mediadores do efeito vasoconstritor da endotelina-1. Diversos estudos demonstraram que a endotelina-1 exerce um papel importante na manutenção do tônus arterial basal. Entretanto, a contribuição da endotelina-1 para o tônus coronariano basal em seres humanos, especialmente em coronárias com lesões ateroscleróticas, permanece alvo de interesse. Objetivos. Os objetivos deste estudo foram avaliar a contribuição da endotelina-1 no tônus coronariano epicárdico e na microcirculação em coronárias livres de lesões obstrutivas e em coronárias com lesões ateroscleróticas e comparar o método da contagem TIMI com o Doppler intracoronário na detecção de alterações do fluxo sangüíneo em resposta à adenosina. Métodos. Um total de 16 pacientes, sendo oito destes no grupo com coronárias livres de lesões obstrutivas e oito pacientes com lesões coronarianas obstrutivas, foram incluídos neste estudo. Todos pacientes receberam a infusão seletiva intracoronária de BQ-123, um inibidor específico dos receptores ETA da endotelina-1, durante 60 minutos. Adenosina e nitroglicerina foram administradas em bolus no tronco da coronária esquerda. O efeito do BQ-123 no diâmetro coronário epicárdico foi avaliado por angiografia quantitativa realizada a cada 15 minutos ao longo da infusão da droga. O efeito na microcirculação coronária foi avaliado por variações no fluxo sangüíneo medido por guia-Doppler e pelo método da contagem TIMI. Resultados. A infusão de BQ-123 resultou em aumento de 7% do diâmetro coronário e de 19% no fluxo sangüíneo volumétrico em pacientes com artérias livres de lesões obstrutivas (P < 0,001 para comparação com basal). O aumento do calibre do vaso ocorreu de forma progressiva e uniforme ao longo do vaso. Os pacientes com lesão aterosclerótica apresentaram um aumento de 16% (P < 0,001 para comparação com artérias livres de lesões obstrutivas) no diâmetro coronário e 28% no local da estenose. A velocidade do fluxo sangüíneo em coronárias livres de lesões obstrutivas não se alterou significativamente tanto na medida por Doppler como pelo método de contagem TIMI. Houve uma correlação de 0,67 (P < 0,05) entre o método da contagem TIMI e o Doppler para detecção de alterações na velocidade do fluxo sangüíneo em resposta à adenosina. Conclusões. A infusão seletiva intracoronária do inibidor específico dos receptores ETA da endotelina-1 em seres humanos pode ser feita de maneira segura. A endotelina-1 exerce um papel importante na manutenção do tônus coronariano basal em artérias livres de lesões obstrutivas, sendo responsável pela quase totalidade do tônus constritor aumentado presente em coronárias com lesões ateroscleróticas. O método da contagem TIMI apresenta uma boa correlação com o Doppler para medida do fluxo sangüíneo em condições de hiperêmia.

Vitrificação de embriões Mus domesticus domesticus contidos em volumes diferentes de 9,0 m de etileno glicol.

Os experimentos tiveram como objetivo determinar a taxa de eclosão dos embriões vitrificados em volumes diferentes de 9,0 M de etileno glicol. Simultaneamente, testou-se dois procedimentos de estocagem dos fios de teflon, denominados caixa de aço inoxidável e globete/raque. No experimento I, os 881 embriões coletados foram distribuídos em 4 tratamentos: tratamento 1 (T1= controle): 307 embriões foram cultivados in vitro em meio PBSm, acrescido de 0,4% de BSA; tratamento 2 (T2): 292 embriões foram expostos à solução de glicerol 10% acrescida de 0,4% de BSA, envasados em palhetas de 0,25 mL e submetidos ao congelamento pelo método rápido em Biocool; tratamento 3 (T3): 138 embriões foram expostos durante 2 minutos à solução de desidratação (10% de EG + 6% BSA em PBSm) e então transferidos para a solução de vitrificação (50% de EG + 6% de BSA em PBSm), onde permaneceram por 30 segundos e foram colocados em volume de 1 μL no interior de um fio de teflon, medindo 0,4 mm de diâmetro, 2,0 cm de comprimento e 0,05 mm de espessura. Os fios foram acondicionados em uma caixa de aço inoxidável para serem armazenados em nitrogênio líquido; tratamento 4 (T4): 144 embriões foram expostos à solução de desidratação (10% de EG + 6% BSA em PBSm) e após 2 minutos, foram transferidos para a solução de vitrificação (50% de EG + 6% BSA em PBSm), onde permaneceram por 30 segundos, sendo após transferidos para um volume de 1 μL no interior do fio de teflon. Os fios de teflon foram estocados em globetes unidos às raques e mantidos em nitrogênio líquido. Após o aquecimento, os embriões foram cultivados em PBSm suplementado com 0,4% de BSA. As taxas de eclosão embrionária observadas foram: T1=76,29% (245/307); T2=41,05% (117/292); T3=37,98% (54/138) e T4=26,78% (37/144). No segundo experimento, 747 embriões foram distribuídos em 3 tratamentos: tratamento 1 (T1= controle): 80 embriões foram cultivados in vitro em meio KSOM acrescido de 0,4% de BSA; tratamento 2 (T2): 334 embriões expostos em solução de glicerol 10% acrescida de 0,4% de BSA, foram envasados em palhetas de 0,25 mL e submetidos ao congelamento pelo método rápido em Biocool; tratamento 3 (T3): 333 blastocistos foram expostos durante 2 minutos à solução de desidratação (10% de EG + 0,4% BSA em PBSm) e então transferidos para tubos eppendorf de 2,0 mL em contato com a solução de vitrificação (50% de EG + 0,4% BSA em PBSm). Após o cultivo in vitro, as taxas de eclosão embrionária observadas nos 3 tratamentos foram respectivamente: 88,75% (71/80), 40,44% (141/334) e 19,70% (66/333). Baseado nesses resultados conclui-se que embriões Mus domesticus domesticus submetidos à técnica de vitrificação após exposição à solução de 9,0 M de etileno glicol e envase em fios de teflon assegurou índices satisfatórios de sobrevivência embrionária. As taxas de sobrevivência dos embriões Mus domesticus domesticus foi independente do procedimento de estocagem em botijão de nitrogênio líquido. A vitrificação em solução de 9,0 M de etileno glicol com envase em tubos eppendorf não foi eficiente para promover altas taxas de sobrevivência embrionária, mas proporcionou segurança biológica aos embriões, durante o armazenamento.

Avaliação de risco de crédito para uma instituição financeira : um estudo exploratório envolvendo o setor industrial da região sul do Brasil

O mercado financeiro nacional vem experimentando mudanças significativas a partir da implantação do novo padrão monetário em 1994. Como conseqüência, os ganhos do sistema bancário, decorrentes do floating foram reduzidos, obrigando os bancos a expandirem suas carteiras de empréstimos que demandam esforços em medir e administrar o risco de crédito. Valendo-se de indicadores econômicofinanceiros e variáveis, o presente estudo visa avaliar a eficácia desses indicadores e variáveis utilizados por uma instituição financeira nacional no processo de concessão de crédito a empresas do setor industrial da região sul do Brasil. A metodologia do estudo propõe inicialmente uma análise estatística dos dados através da Análise da Regressão Logística, procedimentos – enter e stepwise. Concluído o teste de um modelo de previsão de insolvência empresarial, verifica-se quais são os indicadores e variáveis mais significativos e que proporcionam informações valiosas sobre a saúde financeira das empresas, revelando uma possível tendência ao desequilíbrio e a probabilidade à insolvência, levando-se em conta também como informação no gerenciamento do risco de crédito. O estudo mostrou que as variáveis que relacionam a liquidez seca e o saldo de tesouraria / necessidade de capital de giro apresentaram-se como os mais significativos dos sintomas de insolvência.