Characterizing Cardiac Electrophysiology during Radiofrequency Ablation : An Integrative Ex vivo, In silico, and In vivo Approach

Catheter ablation is a major treatment for atrial tachycardias. Hereby, the precise monitoring of the lesion formation is an important success factor. This book presents computational, wet-lab, and clinical studies with the aim of evaluating the signal characteristics of the intracardiac electrograms (IEGMs) recorded around ablation lesions from different perspectives. The detailed analysis of the IEGMs can optimize the description of durable and complex lesions during the ablation procedure

Pitaia, da propagação à colheita: uma revisão

Novas frutas vêm conquistando consumidores e despertando a atenção de agricultores e agricultoras como alternativas de renda. É o caso da pitaia, fruta originária da América tropical com grande potencial de adaptação à diversas condições edafoclimáticas e que oferece diversos benefícios à saúde de seus consumidores. O objetivo desta revisão bibliográfica é apresentar resultados de teses de doutorado e de dissertações de mestrado sobre o cultivo de base ecológica de pitaia, abordando aspectos sobre a propagação, instalação do pomar, até a colheita e pós-colheita. Além disso, considerações são traçadas sobre as potencialidades do cultivo para a agricultura familiar, como alternativa de diversificação produtiva e econômica das propriedades rurais.New fruits have been gaining consumers and attracting the attention of farmers as income alternatives. This is the case of the pitaya, fruit originating in tropical America with great potential for adaptation to diverse soil and climatic conditions with several benefits to the health of his consumers. The objective of this bibliographical review is to present results of doctoral theses and dissertations on pitaya’s ecological base crop, covering aspects of propagation, orchard installation, until harvest and post-harvest. In addition, considerations were draw up about the potential of cultivation for family farming, as an alternative of productive and economic diversification of rural properties.

Simulation of intracardiac electrograms around acute ablation lesions

Radiofrequency ablation (RFA) is a widely used clinical treatment for many types of cardiac arrhythmias. However, nontransmural lesions and gaps between linear lesions often lead to recurrence of the arrhythmia. Intracardiac electrograms (IEGMs) provide real-time information regarding the state of the cardiac tissue surrounding the catheter tip. Nevertheless, the formation and interpretation of IEGMs during the RFA procedure is complex and yet not fully understood. In this in-silico study, we propose a computational model for acute ablation lesions. Our model consists of a necrotic scar core and a border zone, describing irreversible and reversible temperature induced electrophysiological phenomena. These phenomena are modeled by varying the intra- and extracellular conductivity of the tissue as well as a regulating zone factor. The computational model is evaluated regarding its feasibility and validity. Therefore, this model was compared to an existing one and to clinical measurements of five patients undergoing RFA. The results show that the model can indeed be used to recreate IEGMs. We computed IEGMs arising from complex ablation scars, such as scars with gaps or two overlapping ellipsoid scars. For orthogonal catheter orientation, the presence of a second necrotic core in the near-field of a punctiform acute ablation lesion had minor impact on the resulting signal morphology. The presented model can serve as a base for further research on the formation and interpretation of IEGMs

Alternativas de gestão ambiental aplicadas em unidades familiares atuantes na pecuária leiteira do município de Rio Grande, Rio Grande do Sul

A pecuária leiteira familiar é uma importante atividade para as unidades produtoras no município de Rio Grande na região sul do estado, atualmente muitas famílias ainda exercem essa atividade, devido às condições favoráveis da região. Sabendo das limitações e das dificuldades que se tem para alcançar uma produção ambientalmente responsável, o presente trabalho se trata de pesquisa qualitativa de inspiração etnográfica, em que se buscou refletir sobre a adoção de práticas sustentáveis na produção leiteira da Agricultura Familiar. Desse modo, durante a pesquisa de campo (que foi realizada em três propriedades, uma administrada de forma tradicional, outra gerida por um jovem e uma de gerência feminina) foram aplicadas as seguintes técnicas: observação participante, elaboração de diários de campo e entrevistas semiestruturadas. Esse trabalho se justifica ao constatarmos que as pequenas propriedades rurais, atuantes na pecuária leiteira, têm encontrado dificuldades para se adequarem a uma produção sustentável ambientalmente. A adoção de práticas de produção ambientalmente responsáveis é frequentemente inviável para as pequenas propriedades, dado os custos decorrentes das mudanças necessárias no sistema produtivo. Assim, considerando as singularidades da produção leiteira da Agricultura Familiar, esse trabalho buscou responder ao seguinte problema de pesquisa: como os pequenos produtores de leite do município de Rio Grande/RS, percebem o desenvolvimento sustentável? Os resultados dessa pesquisa nos mostram que as práticas de produção mais limpa só são aderidas pelos produtores se resultarem em valores econômicos viáveis para as unidades, e que esses interlocutores muitas vezes não tem um olhar voltado para o desenvolvimento ambientalmente responsável por falta de apoio técnico motivador desta prática, que poderia ser passado a eles por intermédio das organizações extensionistas, que apontadas por eles são os maiores apoiadores e incentivadores da produção leiteira na Agricultura Familiar.Family dairy farming is an important activity for production units in the municipality of Rio Grande in the southern region of the state, currently many families still carry out this activity, due to the favorable conditions in the region for the development of this activity. Knowing the limitations and difficulties that one has to achieve an environmentally responsible production, the present work is a qualitative research with an ethnographic approach, in which it sought to reflect on the adoption of sustainable practices in the dairy production of Family Farming. Thus, during the field research (which was carried out in two properties, one managed in a traditional way and the other managed by a young man) the following techniques were applied: participant observation, preparation of field diaries and interviews based on a semi-structured script. This work is justified by the fact that small rural properties, active in dairy farming, have found it difficult to adapt to an environmentally sustainable production. The adoption of environmentally responsible production practices is often unfeasible for small properties, given the costs resulting from the necessary changes in the production system. Thus, considering the singularities of milk production in Family Agriculture, this work sought to answer the following research problem: how do small milk producers in the city of Rio Grande/RS perceive sustainable development. The results of this research show us that cleaner production practices are only adhered to by producers if they result in viable economic values for the units, and that these interlocutors often do not have an eye towards environmentally responsible development due to a lack of motivating technical support. of this practice, which could be passed on to them through extension organizations, which they point out to be the biggest supporters and encouragers

The effect of microwave energy on sintering of an austenitic stainless steel reinforced with boron carbide

Microwave heating has emerged as an alternative to traditional sintering methods because it consumes less energy and requires shorter processing times. The use of microwave energy in the processing of austenitic stainless steel AISI 316L reinforced with dispersed boron carbide particles was investigated in this study. Different processing parameters were used to investigate the effect of sintering time and temperature, as well as the weight percentage of the ceramic added to the steel matrix, on the final material properties. The compressibility curve, elastic relaxation, and geometric density of green compacts were used to investigate their physical properties. The Archimedes method was used to determine density, and the statistical treatment of analysis of variance was used to determine porosity. Images obtained using optical microscopy and scanning electron microscopy revealed the formation of a second phase in different volumes. The results showed that 1100 °C and a 15-minute plateau were sufficient to sinter the material. AISI 316L samples containing 3 wt.% boron carbide demonstrated greater volumetric formation of secondary phases, resulting in a significant increase in the hardness of the austenitic composite developed

Le strategie di gestione del personale nel caso "dell'espatrio" dei dirigenti

The objective of this study is to investigate the problems faced by “expatriates”. More precisely, the aim is to understand these problems from the point of view of expatriate Brazilians, as well as from that of expatriates living in Brazil. In order to achieve the aforementioned objectives, a preliminary analysis of the literature was conducted to understand if, and how, the problem is suitable for academic study. Moreover, empirical analysis was collected in order to provide a complete perception of the phenomenon, resulting in the creation of multiple case studies and semi structured interviews. Through analysis of the firms Embraco, Bosch and Odebrecht, and interviews with “expatriate” executives, their cultural and social difficulties are addressed, as well as issues related to the adaptation to the new reality is the manager, both in the case of family members being transferred with his family. Another local point os this study is the analysis of company policies with regard to the return or the manager after a period of working abroad. The survey results revealed the numerous advantages and disadvantages of expatriation, all of wich were almost always due to the attention that Human Resources teams usually reserves to this problem. In addition to very positive experiences, this study also recorded experiences that were so bad that the manager was left to resign upon his return