562 research outputs found
Making regulatory mechanisms work : lessons from cases of Private Sector Participation
This paper is about the regulation of private sector participation (PSP) in public water utilities. Using case studies from Argentina, Chile and the United Kingdom, it identifies and discusses the regulatory mechanisms that have been introduced and the issues surrounding information access, price and service quality regulation. The paper also analyses what measures have been implemented in these three cases in order to achieve regulatory accountability, independence and an adequate level of financial and human resources.
The method adopted was case survey including the analysis of official regulatory documents and other relevant material and validation by an expert panel. It investigates the conditions that are necessary for regulatory mechanisms to be implemented and operated effectively in each context, and draws out some general conclusions for areas of improvement
Host Differentiation and Compartmentalization of Microbial Communities in the Azooxanthellate Cupcorals <i>Tubastrea coccinea</i> and <i>Rhizopsammia goesi</i> in the Caribbean
Synthesis and fluorescence properties of side-chain carboxylated 5,9-diaminobenzo[a]phenoxazinium salts
The efficient synthesis of a series of novel side-chain carboxylated 5,9-diaminobenzo[a]phenoxazinium salts is described. The ring system was prepared by the reaction of 5-alkylamino-2-nitrosophenol hydrochlorides with the appropriate N-alkylated-naphthylamine. Evaluation of the visible and fluorescence properties of the cationic dyes was carried out in ethanol and water at physiological pH. In both solvents they showed intense visible absorption maxima in the range 500-638 nm (ethanol) and 625-650 (water), and fluoresced strongly, with fluorescence maxima from 612 to 669 nm (ethanol) and from 654 to 685 nm (water). A wide variation in fluorescence quantum yields is observed, ranging from 0.051 to 0.50 and 0.065 to 0.32 in ethanol and water, respectively.Fundação para a Ciência e a Tecnologia (FCT)
Cell size distribution in a random tessellation of space governed by the Kolmogorov-Johnson-Mehl-Avrami model: Grain size distribution in crystallization
The space subdivision in cells resulting from a process of random nucleation
and growth is a subject of interest in many scientific fields. In this paper,
we deduce the expected value and variance of these distributions while assuming
that the space subdivision process is in accordance with the premises of the
Kolmogorov-Johnson-Mehl-Avrami model. We have not imposed restrictions on the
time dependency of nucleation and growth rates. We have also developed an
approximate analytical cell size probability density function. Finally, we have
applied our approach to the distributions resulting from solid phase
crystallization under isochronal heating conditions
Social theory and the politics of big data and method
This article is an intervention in the debate on big data. It seeks to show, firstly, that behind the wager to make sociology more relevant to the digital there lies a coherent if essentially unstated vision and a whole stance which are more a symptom of the current world than a resolute endeavour to think that world through; hence the conclusion that the perspective prevailing in the debate lacks both the theoretical grip and the practical impulse to initiate a much needed renewal of social theory and sociology. Secondly, and more importantly, the article expounds an alternative view and shows by thus doing that other possibilities of engaging the digital can be pursued. The article is thus an invitation to widen the debate on big data and the digital and a call for a more combative social theory
Monitoramento do impacto de genĂłtipos de sorgo tolerantes e sensĂveis Ă toxidez de alumĂnio sobre as comunidades microbianas da rizosfera.
Pre-training autoencoder for lung nodule malignancy assessment using CT images
Lung cancer late diagnosis has a large impact on the mortality rate numbers, leading to a very low five-year survival rate of 5%. This issue emphasises the importance of developing systems to support a diagnostic at earlier stages. Clinicians use Computed Tomography (CT) scans to assess the nodules and the likelihood of malignancy. Automatic solutions can help to make a faster and more accurate diagnosis, which is crucial for the early detection of lung cancer. Convolutional neural networks (CNN) based approaches have shown to provide a reliable feature extraction ability to detect the malignancy risk associated with pulmonary nodules. This type of approach requires a massive amount of data to model training, which usually represents a limitation in the biomedical field due to medical data privacy and security issues. Transfer learning (TL) methods have been widely explored in medical imaging applications, offering a solution to overcome problems related to the lack of training data publicly available. For the clinical annotations experts with a deep understanding of the complex physiological phenomena represented in the data are required, which represents a huge investment. In this direction, this work explored a TL method based on unsupervised learning achieved when training a Convolutional Autoencoder (CAE) using images in the same domain. For this, lung nodules from the Lung Image Database Consortium and Image Database Resource Initiative (LIDC-IDRI) were extracted and used to train a CAE. Then, the encoder part was transferred, and the malignancy risk was assessed in a binary classification—benign and malignant lung nodules, achieving an Area Under the Curve (AUC) value of 0.936. To evaluate the reliability of this TL approach, the same architecture was trained from scratch and achieved an AUC value of 0.928. The results reported in this comparison suggested that the feature learning achieved when reconstructing the input with an encoder-decoder based architecture can be considered an useful knowledge that might allow overcoming labelling constraints.This work is financed by National Funds through the Portuguese funding agency, FCT—Fundação para a Ciência e a Tecnologia within project UIDB/50014/2020
Germline genetic variants of the renin-angiotensin system, hypoxia and angiogenesis in non-small cell lung cancer progression: Discovery and validation studies
Introduction: The renin–angiotensin system (RAS) is involved in cell proliferation, immunoinflammatory response, hypoxia and angiogenesis, which are critical biological processes in lung cancer. Our aim was to study the association of putatively functional genetic polymorphisms in genes coding for proteins involved in RAS, hypoxia and angiogenesis with non-small cell lung cancer (NSCLC) prognosis. Methods: Genotyping of 52 germline variants from genes of the RAS and hypoxic/angiogenic factors/receptors was performed using MassARRAY iPLEX Gold in a retrospective cohort (n = 167) of advanced NSCLC patients. Validation of the resulting genetic markers was conducted in an independent group (n = 190), matched by clinicopathological characteristics. Results: Multivariate analysis on the discovery set revealed that MME rs701109 C carriers were protected from disease progression in comparison with homozygous T (hazard ratio (HR) = 0.5, 95% confidence interval (CI) = 0.2–0.8, p = 0.010). Homozygous A and T genotypes for KDR rs1870377 were at increased risk for disease progression and death compared to heterozygous (HR = 1.7, 95% CI = 1.2–2.5, p = 0.005 and HR = 2.1, 95% CI = 1.2–3.4, p = 0.006, respectively). Carriers of homozygous genotypes for ACE2 rs908004 presented increased risk for disease progression, only in the subgroup of patients without tumour actionable driver mutations (HR = 2.9, 95% CI = 1.3–6.3, p = 0.010). Importantly, the association of homozygous genotypes in MME rs701109 with risk for disease progression was confirmed after multivariate analysis in the validation set. Conclusion: This study provides evidence that MME polymorphism, which encodes neprilysin, may modulate progression-free survival in advanced NSCLC. Present genetic variation findings will foster basic, translational, and clinical research on their role in NSCLC.M.J.C. was supported by the Associação de Estudos Respiratórios and the Portuguese Pulmonology Society
The mesolimbic dopaminergic dysfunction in psychosis: a review of the literature
Introdução: Desde há algumas décadas que
se pensa que uma hiperactividade dopaminérgica
da via mesolĂmbica esteja implicada na
génese dos sintomas positivos da esquizofrenia.
Objectivos: Nesta revisão da literatura procurámos
interligar as várias áreas do conhecimento
actual, procurando fazer a ponte com
a prática clĂnica.
Métodos: Foi efectuada uma pesquisa sistemática
da literatura em inglês, até Abril de
2014 através da PUBMED utilizando como
termos MeSH (medical subject headings)
“mesolimbic” e “psychosis”, tendo-se incluĂdo
revisões da literatura.
Resultados e Conclusões: Foram encontrados
111 artigos, tendo-se excluĂdo 56 por,
apĂłs leitura do resumo, se concluir que nĂŁo
estavam relacionados com o tema. Dos restantes
55 foram seleccionados 14 artigos tendo
sido mantidas as abreviaturas em inglĂŞs
para facilitar a sua consulta posterior. SĂŁo
apresentadas evidĂŞncias sobre o papel desempenhado
por vários sistemas reguladores
no desenvolvimento dos sintomas positivos
associados não apenas a esta doença mas à s
várias perturbações em que ocorrem, assim
como a possĂvel relação entre esses vários
factores. Entre os vários sistemas discutidos
conta-se a influĂŞncia do neurodesenvolvimento,
da regulação pelos receptores nicotĂ-
nicos da acetilcolina, a influĂŞncia dos canais
de potássio KCNQ, a regulação por péptidos
neurotransmissores, pela adenosina e pela
fosfodiesterase 10A, assim como avanços na
compreensĂŁo da etiologia da esquizofrenia.
Trata-se, portanto, de um enunciado do substrato
neurobiolĂłgico dos sintomas positivos.Background: For several decades now it is
thought that dopamine hyperactivity on the
mesolimbic pathway is implied on the genesis
of schizophrenic psychotic symptoms.
Aims: In this review we sought to interconnect
the various areas of current knowledge,
seeking to relate them to clinical practice.
Methods: A systematic English language PUBMED
search was done, using MeSH (medical
subject headings) terms “mesolimbic”
and “psychosis”, until April 2014, including
reviews.
Results and Conclusions: We found 111
papers, and excluded 56 after an abstract
review. We selected 14 papers of the remaining
55. We present evidence on the
part played by the neurodevelopment, acetylcholine
nicotinic receptor regulation,
influence of KCNQ potassium channels,
neurotransmitter peptides, adenosine and
phosphodiesterase 10A, as well as advances
on understanding the etiology of schizophrenia
on the development of psychotic
symptoms associated not only with this disease
but also with several disturbances on
which they can occur, as well as a possible
relation between these various influences,
where it has been possible to do so. It
is, therefore, an enunciation of the neurobiological
substrate underlying psychotic
symptoms
- …