On the Ancestral Compatibility of Two Phylogenetic Trees with Nested Taxa

Compatibility of phylogenetic trees is the most important concept underlying widely-used methods for assessing the agreement of different phylogenetic trees with overlapping taxa and combining them into common supertrees to reveal the tree of life. The notion of ancestral compatibility of phylogenetic trees with nested taxa was introduced by Semple et al in 2004. In this paper we analyze in detail the meaning of this compatibility from the points of view of the local structure of the trees, of the existence of embeddings into a common supertree, and of the joint properties of their cluster representations. Our analysis leads to a very simple polynomial-time algorithm for testing this compatibility, which we have implemented and is freely available for download from the BioPerl collection of Perl modules for computational biology.Comment: Submitte

Studying the effect of diabetes and hyperglycaemia on brain vascular cells

Type II Diabetes Mellitus (T2DM) is a metabolic disease characterised by insulin resistance and hyperglycaemia. Despite extensive research on the pathology of diabetes in various organs, the effect on the brain’s neurovascular unit remains understudied. This neurovascular unit is arguably the fundamental functional unit of the brain and mediates the communication between the systemic circulation and the brain and establishing the blood-brain-barrier (BBB). It is crucial for adjusting the BBB microenvironment by regulating nutrient uptake and toxin removal from the brain. The work in this thesis utilises in vitro models and transcriptomic analysis of human post-mortem of diabetic frontal cortex to explore how hyperglycaemia and hyperglycaemia affects brain microvascular endothelial cells (BMECs). Validating mechanistic hypotheses requires relevant BBB models. Existing models range from immortalized cell lines, primary cultures, or human induced pluripotent stem cell (iPSC) models each with several limitations. In this study, forced expression of the transcription factor genes LEF1, ETS1, and MRTFB was investigated as means to improve iPSC-BMEC differentiation. This approach resulted in improved cultures of BMECs with clear endothelial cell identity based on high expression of VE-CADHERIN, PECAM1, as well as expression of CLDN5. Expression of the three transcription genes was investigated using lentiviral over-expression as well as CRISPR-based gene activation, with the later proving insufficient to robustly induce BMEC identity. Mouse primary BMECs cultures were used to investigate the effects of hyperglycaemia whilst single nuclei RNA sequencing was applied to characterise the molecular state of brain endothelial cells in diabetes. Surprisingly, both approaches found litle or no effect on BMECs biology. In contrast hypertension was associated with 1008 differentially expressed genes, indicating increased BBB vulnerability to hypertension. Altered pathways include hypoxia, synaptic health, and axon guidance. This research challenges existing paradigms, suggesting BBB protection from diabetic insults and vulnerability to hypertension. The proposed BMEC differentiation protocol, particularly through forced lentiviral expression, advances the models available for future disease-mechanism research

Managing customer relationships through price and service quality

This paper examines the ways in which a service provider's policies on pricing and service level affect the size of its customer base and profitability. The analysis begins with the development of a customer behavior model that uses customer satisfaction and depth of relationship as mediators of the impact of price and service level on profitability. Based on this model of customer behavior, the system is analyzed as a queuing network from which the properties of the aggregate population's behavior are derived. The analysis reveals the counterintuitive result that a policy that involves a decrease in prices or an increase in service level may lead to a smaller customer base. However, this policy may also lead to higher profits. The novelty of this result lies in the explanation of the phenomenon: that when the customer base decreases due to a change in prices or service quality, companies may experience gains in profit that result not from a decrease in costs associated with serving fewer customers but from an increase in revenues resulting from the indirect effects of the lower prices or higher level of service on customer behavior. The application of optimization techniques to the model developed in this paper yields optimality conditions through which managers can assess the long-term profitability of their pricing and service-level policies.Customer relationship management; operations/marketing interface; two-part tariffs; service operations management; service quality;

Curiosity, Frontal EEG Asymmetry, and Learning

Curiosity plays a critical role in our daily behaviors and interactions. Yet, very little is known about its psychological and neural underpinnings. By reframing curiosity as the motivation to obtain reward – where the reward is information –, and using frequency-based metrics of frontal brain lateralization, we aimed to investigate the neural correlates of curiosity in the frontal cortex and its effects on subsequent learning. Twenty-one undergraduate students participated in this two-day study by answering 35 general interest trivia questions, while EEG data was being recorded, also indicating their curiosity towards the question. One week later, participants were asked to write down the correct answers to each one of the questions. The results of this study suggested that frontal brain asymmetry (FBA) predicts memory recall, but is not directly correlated with self-reported curiosity. Study limitations and future directions are discussed

Algoritmos de análise de alinhamento de ofertas do mercado de trabalho

A adoção de tecnologias digitais tem prometido a aceleração e agilidade das atividades laborais, processos e modelos de negócio. No entanto, as promessas de ganho estão associados a uma forte necessidade de profissionais qualificados que possuam a capacidade de aplicar o potencial da tecnologia de forma eficiente. Os contextos de trabalhos estão a ser remodelados à medida que novos modelos de interação e integração humana e tecnológica evoluem. Para ser possível aumentar a prontidão do mercado de trabalho em contextos de rápida mudança, é importante que os intervenientes nas empresas, profissionais e responsáveis por políticas públicas estejam cientes da dinâmica e das necessidades do mercado de trabalho. Isto pode ser observado pela lista de anúncios de emprego, contudo, o seu elevado número, requer ferramentas eficientes com o objetivo de os analisar e simplificá-los para que, consequentemente, seja possível retirar conclusões atempadamente e corretamente. Como as propostas de emprego possuem formulações distintas para postos semelhantes, dependendo das empresas que estão a contratar, surge o desafio de estabelecer um equilíbrio para a comparação de propostas de emprego. Neste trabalho, foi feita uma tentativa de mapeamento das propostas de emprego nas ocupações da ESCO (European Skills/Competences, qualifications and Occupations). ESCO é uma ontologia publicada pela União Europeia e as suas ocupações traduzem-se em cargos num determinado emprego e têm associadas as competências essenciais e facultativas ao exercício da ocupação. A ELK (Elasticsearch, Logstash, Kibana) stack foi usada para lidar com o grande volume de propostas de emprego. ELK é uma ferramenta estável que gere avultadas quantidades de dados e, a camada do Kibana, possibilita a rápida exploração dos dados e a criação de painéis de visualização. Os resultados mostram que a ELK stack é uma ferramenta adequada para providenciar uma interpretação visual das dinâmicas do mercado de trabalho. Foram testadas várias formas de alinhamento entre ofertas reais de emprego e as ocupações ESCO. Os melhores resultados revelaram um f1-score de mais de 0.8 no mapeamento de ofertas de emprego de ocupação de nível 1 da ESCO e uma exatidão de 63.75% quando houve a tentativa de prever a ocupação de nível 5. Estes resultados estão alinhados com o estado da arte presente na literatura e são bastante promissores, especialmente quando comparado ao patamar inicial de 40%, e mostra que a ESCO é um bom candidato para estabelecer esse equilíbrio em que permite a comparação das dinâmicas no mercado de trabalho para ambientes distintos.The adoption of digital technologies promises to accelerate the transformation and the agility of processes, work activities and revenue models. Yet, the promised gains come together with dramatic needs for qualified professionals who can effectively leverage the technology potential. Job contexts are being reshaped as new models for the interaction and integration of humans and technologies take shape. To increase the readiness of the job market in fast-changing contexts all stakeholders {companies, professionals, policymakers must be aware of the job market dynamics and needs. These dynamics can be observed from the collection of job announcements, but its high volume requires effective tools for analyzing and simplifying it to draw timely and correct conclusions. As job announcements have distinct formulations for similar roles, depending on the hiring company, this raises the necessity of establishing a common ground for comparing the job offers. In this work, an attempt at mapping job offers to ESCO (European Skills/Competences, qualifications and Occupations) occupations is made. ESCO is an ontology published by the European Union and its occupations are job positions with the mandatory and optional skills associated. ELK (Elasticsearch, Logstash, Kibana) stack was used for dealing with the high volume of job announcements. ELK is a stable tool that can manage large quantities of data and has an effective text search algorithm, the Kibana layer enables the rapid exploration of data and creation of visualization dashboards. Results show that the ELK stack is a suitable tool for providing a visual interpretation of the job market dynamics. Several strategies were tested to align real job offerings with ESCO occupations and the best one revealed an f1 score of over 0.8 in mapping job offers to level 1 ESCO occupations and an accuracy of 63.75% when trying to predict the level 5 Occupation. These results are comparable to the state-of- the-art and are very promising, especially when compared to the baseline of 40%, and shows that ESCO is a good candidate as common ground to enable the comparison of job market dynamics for distinct environments.Mestrado em Engenharia Informátic

Does quantitative easing impacts firms' capital structure?

Esta tese tem como principal objectivo verificar a ocorrência e quantificar o impacto da política monetária Quantitative Easing (ou usando uma tradução livre, flexibilização quantitativa) na estrutura de capitais das empresas. Vai ser apresentadas teorias de política monetária convencionais e não convencionais. De seguida, vai-se analisar a implementação de Quantitative Easing por varios bancos centrais, entre eles a Reserva Federal, o Banco Central Europeu e o Banco de Inglaterra. Por fim, irá ser apresentado uma descrição das principais teorias da estrutura de capitais (teoria trade-off e pecking-order). Os nossos resultados vão contra a literatura existente. De acordo, com os nossos resultados o impacto da política de Quantiative Easing não tem impacto estatistico significativo na politica de financiamento da empresa.The main goal of this thesis is to verify and quantify the impact of monetary policy Quantitative Easing on firms´ capital structure. It will be presented theories about conventional and unconventional monetary theory. Following, it will be analyze the implementation of Quantitative Easing by a few central banks, like the Federal Reserve, the European Central Bank and the Bank of England. Finally, it will be presented a description of the prominent theories of capital structure (trade-off theory and pecking-order). Our results go against existing literature. According to our results the Quantitative Easing impact does not have statistically significance impact on the financing decision policy