Characterizing and Enforcing Consistency of Online Services

While several proposals for the specification and implementation of various consistency models exist, little is known about what is the consistency currently offered by online services with millions of users. Such knowledge is important, not only because it allows for setting the right expectations and justifying the behavior observed by users, but also because it can be used for improving the process of developing applications that use APIs offered by such services and for creating tools that facilitate this process. To fill this gap, in the first part of this thesis, we present a measurement study of the consistency of the APIs exported by four widely used Internet services, the Facebook Feed, Facebook Groups, Blogger, and Google+. To conduct this study, our work develops a simple, yet generic methodology comprising a small number of tests, which probe these services from a user perspective, and try to uncover consistency anomalies, and reports on the analysis of the data obtained from running these tests for a period of several weeks. Our measurement study shows that some of these services do exhibit consistency anomalies, including some behaviors that may appear counter-intuitive for users, such as the lack of session guarantees for write monotonicity. The results show that developers have to deal with consistency anomalies, to provide consistency guarantees they need. To address the challenge of enforcing consistency guarantees on top of existing systems, in the second part of this thesis, we show that it is possible to deploy a middleware between the application and the service, which enables a fine-grained control over the session guarantees that comprise the consistency semantics provided by these APIs, without having to gain access to the implementation of the underlying services. Our solution intercepts all interactions of the client with the online service and uses four different algorithms to enforce each of the session guarantees and also their combination. We evaluated our middleware using the Facebook public API and the Redis data store, and our results show that we are able to provide fine-grained control of the consistency semantics, while incurring in a small local storage and modest latency overhead

Análise comparativa entre ecofuncional por pediatra e ecocardiografia compreensiva por cardiologista em unidade de terapia intensiva pediátrica e neonatal

Introduction: Bedside ultrasound performed by a non-imaging specialist has proven to be a useful tool in the diagnostic evaluation and performance of invasive procedures. Several clinical situations favor manifestations of hemodynamic instability, especially in intensive care units. Nowadays, several pediatric units have used functional echocardiography (fECHO) and, often, before the examination by echocardiography performed by a cardiologista (cECHO). Objective: Compare the accuracy of echocardiography performed by a pediatrician (fECHO) and a cardiologist (cECHO) on neonatal and pediatric patients in an intensive care unit. Material and Methods: Retrospective analysis of the medical records of pediatric patients from zero days to 14 years, admitted to the intensive care unit, with a clinical indication for evaluation by comprehensive echocardiography of anatomical cardiac alterations were also evaluated through ecofunctional by a pediatrician. Results: Eight nine patients were admitted from zero days to 14 years, 55 of whom were male, and 34 were female. The respective sensitivity and specificity of fECHO and cECHO were 80% and 96.2% for the persistence of the ductus arteriosus; 88.4% and 98.4% for congenital acyanotic heart disease; 77.7% and 98.7% for congenital cyanotic heart disease; 83.3% and 98.8% for ventricular hypertrophy; 100% and 100% for pericardial effusion; 76.2% and 96.2% for persistent neonatal pulmonary hypertension. Conclusions: The results demonstrate a good accuracy of the pediatrician performing fECHO compared with a examination performed by the cardiologist, which does not reduce the importance and obligation of expert assessment. The incorporation of fECHO in the routine pediatric evaluation allows for the expansion and improvement of the pediatrician's physical examination.Introdução: A ultrassonografia à beira do leito realizada por não especialista em imagem tem mostrado ser uma ferramenta útil na avaliação diagnóstica e realização de procedimentos invasivos. Diversas situações clínicas favorecem manifestações de instabilidade hemodinâmica, principalmente, nas unidades de terapia intensiva. Neste sentido, unidades pediátricas têm utilizado ecocardiografia funcional, muitas vezes, antes do exame realizado por um ecocardiografista. Objetivo: Avaliar a acurácia da ecocardiografia realizada por pediatra comparativamente à realizada por ecocardiografista em pacientes de uma unidade neonatal e pediátrica de tratamento intensivo. Material e Métodos: Análise retrospectiva dos prontuários de pacientes pediátricos de zero dia a 14 anos, internados na unidade de terapia intensiva, com indicação clínica para avaliação da existência de alterações anatômicas por ecocardiografia compreensiva e que também foram avaliados através da ecocardiografia funcional por pediatra. Resultados: Um total de 89 casos foram analisados com admissão variando de zero dia a 14 anos, sendo 55 do sexo masculino e 34 do sexo feminino. A sensibilidade e especificidade, respectivamente, da ecocardiografia funcional pelo pediatra comparado à ecocardiografia compreensiva feita pelo cardiologista relativamente às alterações encontradas foram: 80% e 96,2% para persistência do canal arterial; 88,4% e 98,4% para cardiopatia congênita acianótica; 77,7% e 98,7% para cardiopatia congênita cianótica e/ou críticas; 83,3% e 98,8% para miocardiopatia hipertrófica; 100% e 100% para derrame pericárdico; e 76,2% e 96,2% para hipertensão pulmonar persistente neonatal. Conclusões: Os resultados demonstram boa acurácia do pediatra realizando a ecocardiografia funcional quando comparado com exame realizado pelo cardiologista (ecocardiografia compreensiva), o que não reduz a importância e obrigatoriedade da análise do especialista. A incorporação da ecocardiografia funcional na avaliação rotineira pediátrica permite expandir e melhorar o exame físico pelo pediatra

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio