441 research outputs found
Schooling Quality in a Cross Section of Countries: a replication exercise and additional results
In this note we begin by replicate the results in “Schooling Quality in a Cross-Section of Countries†[Barro and Lee 2001, Economica 68]. Then, we go further and show that results can be different when more meaningful variables are considered. In particular, school inputs lessen their effects in some specifications, approximating the macroeconomic result from the microeconomic ones.
Анализ на поведението при решения на топ треньори от висша лига преди и след спортното състезание
Submitted article is thorough study of top coaches behavioral responses during the competition. A detailed analysis of the literature /from the last 15 years / is made, focusing on various determinants of sporting success which determine the role of the coach to shine and not be underestimated. It stressed the need to examine current trends, that elucidate the process complexity / behavioral and cognitive / in coaching job.Представената статия е задълбочено проучване на поведенчески реакции на топ треньори по време на състезание. Подробен анализ на литературата / от последните 15 години / е направен, фокусиран върху различните детерминанти на спортния успех, който да подчертае ролята на треньора. Обръща се внимание на необходимостта, да се разгледат съвременните тенденции, които осветляват сложността на процеса /поведенческа и когнитивна/ в треньорската работа.info:eu-repo/semantics/publishedVersio
Transition from endemic behavior to eradication of malaria due to combined drug therapies: an agent-model approach
We introduce an agent-based model describing a
susceptible-infectious-susceptible (SIS) system of humans and mosquitoes to
predict malaria epidemiological scenarios in realistic biological conditions.
Emphasis is given to the transition from endemic behavior to eradication of
malaria transmission induced by combined drug therapies acting on both the
gametocytemia reduction and on the selective mosquito mortality during parasite
development in the mosquito. Our mathematical framework enables to uncover the
critical values of the parameters characterizing the effect of each drug
therapy. Moreover, our results provide quantitative evidence of what is
empirically known: interventions combining gametocytemia reduction through the
use of gametocidal drugs, with the selective action of ivermectin during
parasite development in the mosquito, may actively promote disease eradication
in the long run. In the agent model, the main properties of human-mosquito
interactions are implemented as parameters and the model is validated by
comparing simulations with real data of malaria incidence collected in the
endemic malaria region of Chimoio in Mozambique. Finally, we discuss our
findings in light of current drug administration strategies for malaria
prevention, that may interfere with human-to-mosquito transmission process.Comment: 12 pages, 6 figure
IxDRL: A Novel Explainable Deep Reinforcement Learning Toolkit based on Analyses of Interestingness
In recent years, advances in deep learning have resulted in a plethora of
successes in the use of reinforcement learning (RL) to solve complex sequential
decision tasks with high-dimensional inputs. However, existing systems lack the
necessary mechanisms to provide humans with a holistic view of their
competence, presenting an impediment to their adoption, particularly in
critical applications where the decisions an agent makes can have significant
consequences. Yet, existing RL-based systems are essentially competency-unaware
in that they lack the necessary interpretation mechanisms to allow human
operators to have an insightful, holistic view of their competency. Towards
more explainable Deep RL (xDRL), we propose a new framework based on analyses
of interestingness. Our tool provides various measures of RL agent competence
stemming from interestingness analysis and is applicable to a wide range of RL
algorithms, natively supporting the popular RLLib toolkit. We showcase the use
of our framework by applying the proposed pipeline in a set of scenarios of
varying complexity. We empirically assess the capability of the approach in
identifying agent behavior patterns and competency-controlling conditions, and
the task elements mostly responsible for an agent's competence, based on global
and local analyses of interestingness. Overall, we show that our framework can
provide agent designers with insights about RL agent competence, both their
capabilities and limitations, enabling more informed decisions about
interventions, additional training, and other interactions in collaborative
human-machine settings.Comment: To be published in the Proceedings of the 1st World Conference on
eXplainable Artificial Intelligence (xAI 2023). arXiv admin note: substantial
text overlap with arXiv:2211.0637
Production and characterization of thermoresponsive magnetic membranes
In the last years, the electrospinning technique has proven to be very advantageous to produce polymeric membranes since it originates nanometric fibres with a high surface area/volume ratio. As a result, electrospun nanofibers have been used for different biomedical applications, particularly in the development of multifunctional devices. To increase membrane functionality additional materials such as magnetic nanoparticles (MNPs) that respond to external stimuli can be combined with electrospun fibres. The incorporation of these nanoparticles into electrospun fibres produces a multifunctional system that can be used for cancer theranostic applications.
The main objective of this work was to process a thermoresponsive polymer, polyacrylamide (PAAm), using electrospinning and to incorporate MNPs by their addition to the precursor solution. These membranes will have the ability to respond to two different external stimuli, magnetic field and temperature, being suitable for magnetic hyperthermia application.
In the first phase, an optimization study of the electrospinning parameters was made to obtain monodisperse fibres of PAAm. MNPs were synthesized by chemical precipitation technique and then stabilized with oleic acid or dimercaptosuccinic acid to avoid their aggregation. Later the MNPs were added to the precursor polymeric solution and composite membranes were produced, which were characterized in terms of its mechanical properties, and swelling ability. They were also analysed in terms of morphology, chemical properties and structurally by SEM, FTIR and XRD, respectively.
PAAm fibres with an average diameter of around 200 nm containing iron oxide nanoparticles were produced. This was confirmed by TEM and EDS analysis showing the presence of NPs and iron in the fibres, respectively. The incorporation of MNPs provided fibre reinforcement by increasing the Young’s modulus. Through magnetic hyperthermia measurements, it was possible to obtain a temperature variation of 1.1ºC, demonstrating the potential of this dual-stimuli responsive membranes for magnetic hyperthermia applications
Biological predictors of survival in limphoma and mechanisms underlying follicular lymphoma transformaion into diffuse large B cell lymphoma (vol I e II)
RESUMO: Os biomarcadores tumorais permitem identificar os doentes com maior risco de
recorrência da doença, predizer a resposta tumoral à terapêutica e, finalmente,
definir candidatos a novos alvos terapêuticos. Novos biomarcadores são
especialmente necessários na abordagem clínica dos linfomas. Actualmente,
esses tumores são diagnosticados através de uma combinação de características morfológicas, fenotípicas e moleculares, mas o prognóstico e o planeamento terapêutico estão quase exclusivamente dependentes de
características clínicas. Estes factores clínicos são, na maioria dos linfomas,
insuficientes numa proporção significativa dos doentes, em particular, aqueles
com pior prognóstico. O linfoma folicular (LF) é, globalmente, o segundo subtipo mais comum de linfoma. É tipicamente uma doença indolente com uma sobrevida média entre os 8 e 12 anos, mas é geralmente fatal quando se
transforma num linfoma agressivo de alto grau, habitualmente o linfoma difuso
de grandes células B (LDGCB). Morfologicamente e funcionalmente, as células
do LF recapitulam as células normais do centro germinativo na sua dependência de sobrevivência do microambiente não-tumoral, especialmente das células do sistema imunológico. Biomarcadores preditivos de
transformação não existem pelo que um melhor conhecimento da biologia intrínseca de progressão do LF poderá revelar novos candidatos. Nesta tese descrevo duas abordagens distintas para a descoberta de novos biomarcadores. A primeira, o estudo da expressão global de genes ('genomics')
obtidos por técnicas de alto rendimento que analisam todo o genoma humano sequenciado, permitindo identificar novas anomalias genéticas que possam representar mecanismos biológicos importantes de transformação. São
descritos novos genes e alterações genómicas associados à transformação do LF, sendo especialmente relevantes as relacionadas com os eventos iniciais de transformação em LDGCB. A segunda, baseou-se em várias hipóteses centradas no microambiente do LF, rico em vários tipos de células nãomalignas.
Os estudos imunoarquitectural de macrófagos, células T regulatórias e densidade de microvasos efectuado em biopsias de diagnóstico de doentes com LF tratados uniformemente correlacionaram-se significativamente, e independentemente dos critérios clínicos, com a evolução clínica e, mais importante, com o risco de transformação em LDGCB. Nesta tese, foram
preferencialmente utilizadas (e optimizadas) técnicas que permitam o uso de amostras fixadas em parafina e formalina (FFPET). Estas são facilmente acessíveis a partir das biopsias de diagnóstico de rotina presentes nos arquivos de todos os departamentos de patologia, facilitando uma transição rápida dos novos marcadores para a prática clínica. Embora o FL fosse o tema principal da tese, os novos achados permitiram estender facilmente hipóteses semelhantes a outros subtipos de linfoma. Assim, são propostos e validados vários biomarcadores promissores e relacionados com o microambiente não tumoral,
sobretudo dependentes das células do sistema imunológico, como contribuintes importantes para a biologia dos linfomas. Estes sugerem novas opções para a abordagem clínica destas doenças e, eventualmente, novos alvos terapêuticos.------------- ABSTRACT: Cancer biomarkers provide an opportunity to identify those patients most at risk
for disease recurrence, predict which tumours will respond to different
therapeutic approaches and ultimately define candidate biomarkers that may serve as targets for personalized therapy. New biomarkers are especially needed in the management of lymphoid cancers. At present, these tumours are diagnosed using a combination of morphologic, phenotypic and molecular features but prognosis and overall survival are mostly dependent on clinical
characteristics. In most lymphoma types, these imprecisely assess a significant
proportion of patients, in particular, those with very poor outcomes. Follicular lymphoma (FL) is the second most common lymphoma subtype worldwide. It is typically an indolent disease with current median survivals in the range of 8-12 years, but is usually fatal when it transforms into an aggressive high-grade lymphoma, characteristically Diffuse Large B Cell Lymphoma (DLBCL).
Morphologically and functionally it recapitulates the normal cells of the germinal center with its survival dependency on non-malignant immune and immunerelated
cells. Informative markers of transformation related to the intrinsic biology of FL progression are needed. Within this thesis two separate approaches to biomarker discovery were employed. The first was to study the global expression of genes (‘genomics’) obtained using high-throughput, wholegenome-wide approaches that offered the possibility for discovery of new genetic abnormalities that might represent the important biological mechanisms of transformation. Gene signatures associated with early events of transformation were found. Another approach relied on hypothesis-driven concepts focusing upon the microenvironment, rich in several non-malignant cell types. The immunoarchitectural studies of macrophages, regulatory T cells and microvessel density on diagnostic biopsies of uniformly treated FL patients significantly predicted clinical outcome and, importantly, also informed on the risk of transformation. Techniques that enabled the use of routine formalin fixed
paraffin embedded diagnostic specimens from the pathology department archives were preferentially used in this thesis with the goal of fulfilling a rapid bench-to-beside” translation for these new findings. Although FL was the main subject of the thesis the new findings and hypotheses allowed easy transition into other lymphoma types. Several promising biomarkers were proposed and validated including the implication of several non-neoplastic immune cells as
important contributors to lymphoma biology, opening new options for better treatment planning and eventually new therapeutic targets and candidate therapeutics
Strategic planning in small and medium-sized companies in the architecture sector in Portugal
Architecture today presents a highly competitive and turbulent market. This scenario of
instability and competition has reinforced the importance of strategy and, consequently,
strategic planning. The existing literature indicates that strategic planning allows
companies to achieve a better strategic positioning, performance and profitability. This
exploratory study aims to investigate in the architecture sector the importance given to
strategy, the way strategic planning is used and, finally, what are the main obstacles that
discourage its adoption. Through a set of 12 semi-structured interviews with different
micro, small and medium-sized architecture studios, this research points to a limited use
of strategic planning. This result is explained, on the one hand, by the lack of knowledge
of strategic planning methodologies and by the fact that often financial success and
market share are seen by owner-managers as secondary to other objectives, such as their
intellectual satisfaction and artistic recognition of their work. The volatility of the
construction sector and the small size of most architectural firms also seem to contribute
to their low usage. The results of this dissertation may be of interest to owners/managers
of Architecture firms and also to Architecture universities.Nos dias de hoje, o mercado da arquitetura é caracterizado por ser altamente competitivo
e turbulento. Este cenário de instabilidade e concorrência reforça a importância da
estratégia e, consequentemente, do planeamento estratégico. A literatura existente indica
que o planeamento estratégico permite às empresas conseguir um melhor posicionamento
de mercado, um melhor desempenho e rentabilidade. Este estudo exploratório tem como
objetivo investigar no setor da arquitetura, a importância atribuída ao planeamento
estratégico, a extensão e o modo com que é utilizado e, finalmente, quais os principais
obstáculos que limitam a sua utilização. Através de um conjunto de 12 entrevistas
semiestruturadas a diferentes micro, pequenas e médias empresas de arquitetura, esta
investigação sugere uma utilização limitada do planeamento estratégico. Este resultado é
explicado, por um lado, pela falta de conhecimento no sector das mais valias e
metodologias do planeamento estratégico e pelo facto de muitas vezes o sucesso
financeiro ser visto pelos donos-gestores como secundário em relação a outros objetivos,
tais como a sua satisfação intelectual e o reconhecimento artístico do seu trabalho. A
volatilidade do sector da construção e a pequena dimensão da maioria das empresas de
arquitetura também parecem contribuir para a sua baixa utilização. Os resultados desta
dissertação podem ser do interesse dos gerentes de empresas de arquitetura e também das
universidades do sector
- …