Arquitectura WDM-PON baseada em componentes sintonizáveis

Mestrado em Engenharia Electrónica e TelecomunicaçõesO tema principal abordado neste trabalho é a tecnologia WDM-PON como próxima geração de redes de acesso. Começou por ser feita uma abordagem geral a este tópico, servindo esta como ponto de partida para a parte experimental. Foi proposta e demonstrada uma arquitectura WDM-PON bidirecional directamente modulada baseada em lasers sintonizáveis e receptores sintonizáveis no terminal do utilizador, e um divisor de potência no nó de acesso. Foram também apontados possíveis melhoramentos ao hardware desta arquitectura. Dois formatos de modulação avançados – QPSK e Duobinário – foram abordados, no contexto dos sistemas WDM-PON. Assim sendo, foram testados um sistema coerente QPSK e um sistema UDWDM-QPSK e foram apresentados os resultados obtidos.The main topic of this work is WDM-PON as a technology for next generation access networks. It was first made a general approach to this topic, serving as starting point to the experimental part. It was proposed and demonstrated a bidirectional directly modulated WDM-PON architecture based on tunable lasers and tunable receivers at the users’ end, and a splitter at the Remote Node. Possible improvements to this architecture’s hardware were also pointed out. Two advanced modulation formats – QPSK and Duobinary – were addressed, in the context of WDM-PON systems. Thus, we tested a coherent QPSK and a UDWDM QPSK system and present the obtained results

Time For Chocolate: Current Understanding And New Perspectives On Cacao Witches' Broom Disease Research

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Theobroma cacao is a tropical understory tree that is one of the most important perennial crops in agriculture. Treasured by ancient civilizations in Mesoamerica for over 3,000 years, the cocoa bean now supports a multibillion-dollar industry that is involved in the production and commercialization of chocolate, a treat appreciated worldwide. The cacao tree is originally from the Amazon rainforest and is currently grown in more than 50 countries throughout the humid tropics, serving as a major source of income for over 40 million people. Each year, more than 3 million tons of cocoa beans are produced, mostly by smallholder farmers in areas of high biodiversity. Notably, the cacao tree does not require direct sunlight and naturally grows under the canopy of other, taller trees. This characteristic often encourages farmers to preserve existing forests and to plant additional trees to shelter their cacao plants [1], thereby reducing the environmental impacts of cacao cultivation. Despite its great importance, the cacao tree is affected by a number of untreatable diseases that reduce fruit production and threaten our global supply of cacao. Among them, witches' broom disease (WBD) stands out as one of the most severe problems that affect this crop, accounting for production losses of up to 90%.1110Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [09/50119-9]CNPq [475535/2013-8

Sedimentological characteristics of ice-wedge polygon terrain in Adventdalen (Svalbard): environmental and climatic implications for the late Holocene

Ice wedges are widespread periglacial features in the landscape of Adventdalen, Svalbard. The networks of ice wedges have created areas with well-developed polygonal terrains in the lowest fluvial terraces in this valley. We have examined the sedimentological characteristics of the northern and southern banks of the Advent river for palaeoenvironmental purposes. The base of two sedimentary sections reported radiocarbon dates of 3.3 and 3.9 ka BP, respectively. The northern site is constituted by three very different lithostratigraphical units, which suggests that their formation should be related to different environmental and climate conditions. By contrast, the southern section shows a rather homogeneous composition, with no significant variations in grain size and organic matter content. In both cases the uppermost sediments are constituted by a thick aeolian deposit. According to our data, warmer climate conditions may have prevailed during the mid Holocene until 3.3 ka BP with widespread peat formation in the valley bottom. Subsequently, a period with alternating soil formation and aeolian sedimentation took place from 3 to 2.5 ka BP, probably due to increasing climatic severity. During the last millennium a long-term cooling trend has favoured aeolian deposition in the lowest part of Adventdalen.info:eu-repo/semantics/publishedVersio

Estudo comparativo de controladores Software-Defined Networking (SDN)

The SDN (Software-defined Nettworking) has introduced a new control paradigm in network infrastructures, thus having a great impact not only on the operation of the network itself, but also on supporting all the development carried out around them (e.g. network and distributed services, Internet applications, etc.). In this context, and in order to assist researchers and professionals in these areas, this article presents a comparative study among several SDN controllers in the market. In a first phase, a more general analysis is made on several controllers, highlighting their general characteristics and the areas where some scientific works were developed using each of the controllers. After that, a selection of some controllers is made, and some illustrative microprojects were implemented, allowing to obtain a comparative analysis of the learning curves and some of the main APIs supported by each SDN controller.Este trabalho foi apoiado pela FCT - Fundação para a Ciência e Tecnologia no âmbito do Projeto UID/CEC/00319/2019

Processo De Fermentacao Com Uso Demicroorganismos Floculantes Condicionais

Processo de fermentação com uso de micro-organismos floculantes condicionais, o qual compreende a geração e utilização de linhagens floculantes condicionais de micro-organismos, que partem de uma linhagem selvagem não floculante, na qual é então introduzido um gene de floculação com o seu promotor modificado, sendo que essa modificação do promotor visa tornar a expressão do gene de floculação reprimida à presença de um substrato especifico.BR0001122 (B1); BR0001122 (A)C12N15/81C12P7/06C12P7/06C12N15/81BR20000001122C12N15/81C12P7/06C12P7/06C12N15/8

Reforestation and land use change as drivers for a decrease of avalanche damage in mid-latitude mountains (NW Spain)

Natural conditions that explain the triggering of snow avalanches are becoming better-known, but our understanding of how socio-environmental changes can influence the occurrence of damaging avalanches is still limited. This study analyses the evolution of snow avalanche damage in the Asturian Massif (NW Spain) between 1800 and 2015, paying special attention to changes in land-use and land-cover patterns. A damage index has been performed using historical sources, photointerpretation and fieldwork-based data, which were introduced in a GIS and processed by means of statistical analysis. Mapping allowed connecting spatiotemporal variations of damage and changes in human-environment interactions. The total number of victims was 342 (192 dead and 150 injured). Results show stability in the number of avalanches during the study period, but a progressive decrease in the damage per avalanche. Changes in land use explain the evolution of damage and its spatial/temporal behaviour. The role played by vegetation cover is at the root of this process: damage was the highest during the late 19th and early 20th centuries, when a massive deforestation process affected the protective forest. This deforestation was the result of demographic growth and intensive grazing, disentailment laws and emerging coal mining. Since the mid-20th century, the transformation of a traditional land-management system based on overexploitation into a system based on land marginalization and reforestation, together with the decline of deforestation due to industrial and legal causes, resulted in the decrease of avalanches that affected settlements (mostly those released below the potential timberline). The decrease of damage has been sharper in the western sector of the Asturian Massif, where oak deforestation was very intense in the past and where lithology allows for a more successful ecological succession at present. Taking into account that reforestation can be observed in mountain environments of developed countries worldwide, and considering present initiatives conducted to counteract its negative cultural effects by means of grazing and clearing operations, planning is imperative, and this research provides useful information for environmental management policies and risk mitigation in avalanche prone areas.info:eu-repo/semantics/publishedVersio

A porosity model for medical image segmentation of vessels

A physics-based medical image segmentation method is developed. Specifically, the image greyscale intensity is used to infer the voxel partial volumes and subsequently formulate a porous medium analogy. The method involves first translating the medical image volumetric data into a three-dimensional computational domain of a porous material. A velocity field is then obtained from numerical simulations of incompressible fluid flow in the porous material, and finally a velocity iso-surface provides the surface description of the target object. The approach is tested on CT images of eight patient-specific cases, where cerebral aneurysms, nasal cavities (NC), and an aortic arch (AA) are the objects of interest. In the aneurysm cases, the results are compared against constant greyscale thresholding and manual segmentation. The manual segmentations of the aneurysms are validated by a clinical practitioner. Only a qualitative comparison is available for the NC, and the AA geometries. The results show that the proposed method is effective and capable of extracting the target object in a noisy domain. A sensitivity study is carried out to verify the method's performance with respect to modelling or user choices. The segmentation by the proposed method is also evaluated by performing computational fluid dynamics simulation, including a near-wall flow analysis, to ensure that the segmented geometry and the resulting computed solution are representative and meaningful

Progesterone differentially affects the transcriptomic profiles of cow endometrial cell types

Background The endometrium is a heterogeneous tissue composed of luminal epithelial (LE), glandular epithelial (GE), and stromal cells (ST), experiencing progesterone regulated dynamic changes during the estrous cycle. In the cow, this regulation at the transcriptomic level was only evaluated in the whole tissue. This study describes specific gene expression in the three types of cells isolated from endometrial biopsies following laser capture microdissection and the transcriptome changes induced by progesterone in GE and ST cells. Results Endometrial LE, GE, and ST cells show specific transcriptomic profiles. Most of the differentially expressed genes (DEGs) in response to progesterone are cell type-specific (96%). Genes involved in cell cycle and nuclear division are under-expressed in the presence of progesterone in GE, highlighting the anti-proliferative action of progesterone in epithelial cells. Elevated progesterone concentrations are also associated with the under-expression of estrogen receptor 1 (ESR1) in GE and oxytocin receptor (OXTR) in GE and ST cells. In ST cells, transcription factors such as SOX17 and FOXA2, known to regulate uterine epithelial-stromal cross-talk conveying to endometrial receptivity, are over-expressed under progesterone influence. Conclusions The results from this study show that progesterone regulates endometrial function in a cell type-specific way, which is independent of the expression of its main receptor PGR. These novel insights into uterine physiology present the cell compartment as the physiological unit rather than the whole tissue

Role of Room Temperature Sputtered High Conductive and High Transparent Indium Zinc Oxide Film Contacts on the Performance of Orange, Green, and Blue Organic Light Emitting Diodes

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