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Unravelling the specific growth dynamics of key tissues and organs is fundamental to understand how multicellular organisms orchestrate their different growth programmes. In plants, the secondary growth (thickening) of stems and roots provides the mechanical support that plants need to achieve their developmental potential. We used conventional anatomical and microscopy techniques, image-processing software, and quantitative analysis to understand and mathematically describe the growth dynamics of the early developmental stages of secondary xylem (the main tissue developed during secondary growth). Results show that such early developmental stages are characterized by exponential expansion of secondary xylem in 3D in the form of an inverted cone, with a power law that describes the relationship between the area of the base and the longitudinal progression (height) of the growing secondary xylem cone over time with a scaling exponent of 2/5: the signature of allometric growth. Our work constitutes a starting point for future modelling of secondary xylem in particular and secondary growth in general.

Unravelling the specific growth dynamics of key tissues and organs is fundamental to understand how multicellular organisms orchestrate their different growth programmes. In plants, the secondary growth (thickening) of stems and roots provides the mechanical support that plants need to achieve their developmental potential. We used conventional anatomical and microscopy techniques, image-processing software, and quantitative analysis to understand and mathematically describe the growth dynamics of the early developmental stages of secondary xylem (the main tissue developed during secondary growth). Results show that such early developmental stages are characterized by exponential expansion of secondary xylem in 3D in the form of an inverted cone, with a power law that describes the relationship between the area of the base and the longitudinal progression (height) of the growing secondary xylem cone over time with a scaling exponent of 2/5: the signature of allometric growth. Our work constitutes a starting point for future modelling of secondary xylem in particular and secondary growth in general.

Dissertation presented to obtain the Ph.D degree in Biology Wood is one of the most important natural renewable resources. The developmental processes that underlie wood formation follow a well defined sequence of events that start at the core of the vascular cambium - the stem cell niche - that perpetually nourishes cells to the inside of the stem that ultimately become xylem/wood cells. The processes of specification and differentiation of cells into the xylem cell-types are far from being fully understood. It is a known fact that cells fated to become xylem have to commit suicide in order to serve this purpose.(...)

Dissertação de Mestrado em Contabilidade e Administração, Com as economias mundiais cada vez mais globalizadas, torna-se cada vez mais necessária a harmonização da informação que é produzida pelas empresas ao nível do seu Relato Contabilístico. Neste contexto, muitos têm sido os estudos encetados por diversos organismos a nível mundial, no sentido de encontrar um Modelo de Relato ajustado às necessidades de informação dos utilizadores. O Relatório Jenkins (AICPA, 1994), coloca a ênfase no Relato do Negócio, dando corpo a ideias das propostas mais recentes. A este seguiram-se outras propostas tais como o MD&A, OFR, BSC entre outros, e recentemente, encontra-se em estudo uma proposta do IASB para a adopção de um Modelo de Relato Harmonizado, intitulado Management Commentary (MC). Neste sentido, o propósito do nosso estudo será avaliar o nível de conhecimento e a importância atribuída pelas empresas da Região Centro de Portugal à informação contida nestes Modelos de Relato, bem como avaliar a informação actualmente produzida de acordo com esses Modelos. Assim, elaborámos um questionário com base em 40 itens de informação, inerentes ao Relatório Jenkins, MC, OFR e Balanced Scorecard, com o propósito atrás referido. Concluímos que as empresas já produzem muita da informação dos Modelos, embora não tenham grande conhecimento acerca dos mesmos. A informação dos Modelos OFR e Relatório Jenkins revelou-se como a mais produzida e a mais importante para uso interno. Já relativamente à produção e importância da informação para divulgação ao exterior, a informação dos Modelos BSC e MC revelou-se como a mais produzida e importante. A informação prospectiva apresentou-se como aquela em que as empresas sentem maiores necessidades de informação, para uso interno. Por último, do estudo da associação dos Modelos com quatro variáveis de caracterização das empresas analisadas, os testes permitiram concluir não ser de rejeitar a hipótese de existência de associação entre essas variáveis e os Modelos., With the increasingly globalization, there is a great need for accounting harmonization. This include, the information disclosed by companies through their annual reports. On that context, many are the studies developed by accounting bodies, worldwide, in order to find a Reporting Model suitable with user needs. The Jenkins Report (AICPA, 1994), make the case towards business reporting and draw the main ideas of the subsequent proposals. After that, MD&A, OFR, BSC among other proposals, and more recently, the IASB Management Commentary, may be seen as designs of business reporting models. On that sense, the purpose of this study is to evaluate the level of knowledge of the models and the importance of their information, to the companies of the Centre Region of Portugal, and also to evaluate the information that is now being produced, according to those models. So, we have organized a questionnaire based on 40 items of information concerned with the Models Jenkins Report, MC, OFR e Balanced Scorecard. We concluded that companies produce many of the models information, although they don’t have too much knowledge about them. The OFR and Jenkins Report Model information is the most produced and the most important for internal purposes. However, for external purposes, the BSC and MC models information are the more produced and the more important. The prospective information is the more important for internal purposes, and also the one where there is a lack of information. Lastly, from the study of the relation of the models and four firm’s characterizing variables, we concluded that we should not reject the hypotheses that there is a relation among the characterizing variables and the models.