Query optimizers based on machine learning techniques

Dissertação de mestrado integrado em Engenharia InformáticaQuery optimizers are considered one of the most relevant and sophisticated components in a database management system. However, despite currently producing nearly optimal results, optimizers rely on statistical estimates and heuristics to reduce the search space of alternative execution plans for a single query. As a result, for more complex queries, errors may grow exponentially, often translating into sub-optimal plans resulting in less than ideal performance. Recent advances in machine learning techniques have opened new opportunities for many of the existing problems related to system optimization. This document proposes a solution built on top of PostgreSQL that learns to select the most efficient set of optimizer strategy settings for a particular query. Instead of depending entirely on the optimizer’s estimates to compare different plans under different configurations, it relies on a greedy selection algorithm that supports several types of predictive modeling techniques, from more traditional modeling techniques to a deep learning approach. The system is evaluated experimentally with the standard TPC-H and Join Order ing Benchmark workloads to measure the cost and benefits of adding machine learning capabilities to traditional query optimizers.Os otimizadores de queries são considerados um dos componentes de maior relevância e complexidade num sistema de gestão de bases de dados. No entanto, apesar de atualmente produzirem resultados quase ótimos, os otimizadores dependem do uso de estimativas estatísticas e de heurísticas para reduzir o espaço de procura de planos de execução alternativos para uma determinada query. Como resultado, para queries mais complexas, os erros podem crescer exponencialmente, o que geralmente se traduz em planos sub-ótimos, resultando num desempenho inferior ao ideal. Os recentes avanços nas técnicas de aprendizagem automática abriram novas oportunidades para muitos dos problemas existentes relacionados com otimização de sistemas. Este documento propõe uma solução construída sobre o PostgreSQL que aprende a selecionar o conjunto mais eficiente de configurações do otimizador para uma determinada query. Em vez de depender inteiramente de estimativas do otimizador para comparar planos de configurações diferentes, a solução baseia-se num algoritmo de seleção greedy que suporta vários tipos de técnicas de modelagem preditiva, desde técnicas mais tradicionais a uma abordagem de deep learning. O sistema é avaliado experimentalmente com os workloads TPC-H e Join Ordering Benchmark para medir o custo e os benefícios de adicionar aprendizagem automática a otimizadores de queries tradicionais.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

Functional status following pulmonary rehabilitation in patients with interstitial lung disease

Pulmonary rehabilitation (PR) is effective in improving symptoms, exercise capacity and quality of life in patientswith interstitial lung disease (ILD). However, little is known about its effects on other meaningful outcomes, suchas functional status. Thus, we aimed to explore whether PR can improve functional status in patients with ILD.Participants enrolled in a 12-week multidisciplinary community-based PR programme, which included exercisetraining, education and psychosocial support. Performance-based functional tests (6-Min Walk Test (6MWT),1-Min Sit-to-Stand Test (1-STS), Chester Step Test (CST), Glittre ADL-Test (TGlittre), Timed Up and Go (TUG),Physical Performance Test (PPT) and Grocery Shelving Task (GST)) were used to assess functional statusbefore and after PR. Based on normality of data distribution, a Paired t-Test or Wilcoxon Signed-Rank Test (w/listwise deletion) were computed in IBM SPSS® 27.0. Data are presented as mean ±SD or median [IQR]. 53patients with ILD (62.3% female; 64.5±1.7years; FVC%pred 80.9±18.2; DLCO%pred 54.8±18.1) participated.6MWT (n=45; 422.8±133.5 vs. 465.6±130.3, p <0.001), 1-STS (n=45; 23.5±7 vs. 29±11, p <0.001), CST (n=43;70 [39-96] vs. 72 [50-153], p=0.001) and TGlittre (n=27; 3.27 [3.03-4.16] vs. 2.58 [2.31-3.31], p=0.005) improvedsignificantly following PR. No significant within-group differences were observed for TUG (n=40 p=0.128), PPT(n=37 p=0.853) and GST (n=40 p=0.909). PR shows to be beneficial in improving functional status in patients with ILD. Additional studies are needed to determine the psychometric properties for some of the reported measures.publishe

A speleothem record from Portugal reveals phases of increased winter precipitation in western Iberia during the Holocene

The European climate during the Holocene period is characterised by frequent changes of temperature and precipitation. The North Atlantic plays a major role as a driver for European climate and is a dominant precipitation source, particularly for the western European and north African realm. Atmospheric pressure gradients over the Atlantic (North Atlantic Oscillation, NAO), Atlantic circulation patterns (Atlantic Multidecadal Oscillation, AMO) or positioning of the Atlantic jet stream have been suggested to be responsible for precipitation patterns across western Europe. However, proxy data provide an inconsistent picture on how precipitation responds to changes in the Atlantic realm such as changes of Atlantic temperature(IRD), atmospheric pressure (NAO), water circulation (AMO) or the jet stream. Here we present a record of speleothem-based winter precipitation amount from Portugal. The record covers most of the Holocene and demonstrates that wetter conditions were synchronous in western and southern Iberia during early and mid Holocene. The record also shows a correlation between increased winter precipitation amount in western Iberia and Atlantic cooling, evidenced by Bond events, between 10 and 4 ka

Quantitative Risk Assessment of Oocyst Versus Bradyzoite Foodborne Transmission of \u3ci\u3eToxoplasma gondii\u3c/i\u3e in Brazil

Toxoplasma gondii is a globally distributed zoonotic protozoan parasite. Infection with T. gondii can cause congenital toxoplasmosis in developing fetuses and acute outbreaks in the general population, and the disease burden is especially high in South America. Prior studies found that the environmental stage of T. gondii, oocysts, is an important source of infection in Brazil; however, no studies have quantified this risk relative to other parasite stages. We developed a Bayesian quantitative risk assessment (QRA) to estimate the relative attribution of the two primary parasite stages (bradyzoite and oocyst) that can be transmitted in foods to people in Brazil. Oocyst contamination in fruits and greens contributed significantly more to overall estimated T. gondii infections than bradyzoite-contaminated foods (beef, pork, poultry). In sensitivity analysis, treatment, i.e., cooking temperature for meat and washing efficiency for produce, most strongly affected the estimated toxoplasmosis incidence rate. Due to the lack of regional food contamination prevalence data and the high level of uncertainty in many model parameters, this analysis provides an initial estimate of the relative importance of food products. Important knowledge gaps for oocyst-borne infections were identified and can drive future studies to improve risk assessments and effective policy actions to reduce human toxoplasmosis in Brazil

Early evidence of fire in south-western Europe: the Acheulean site of Gruta da Aroeira (Torres Novas, Portugal)

The site of Gruta da Aroeira (Torres Novas, Portugal), with evidence of human occupancy dating to ca. 400 ka (Marine Isotope Stage 11), is one of the very few Middle Pleistocene localities to have provided a fossil hominin cranium associated with Acheulean bifaces in a cave context. The multi-analytic study reported here of the by-products of burning recorded in layer X suggests the presence of anthropogenic fires at the site, among the oldest such evidence in south-western Europe. The burnt material consists of bone, charcoal and, possibly, quartzite cobbles. These finds were made in a small area of the cave and in two separate occupation horizons. Our results add to our still-limited knowledge about the controlled use of fire in the Lower Palaeolithic and contribute to ongoing debates on the behavioural complexity of the Acheulean of Europe.Financial support for the archaeological fieldwork undertaken at the Almonda karst sites was provided by the Municipality of Torres Novas and by projects PTDC/HIS-ARQ/098164/2008 and PTDC/HAR-ARQ/30413/2017, funded by FCT (Fundação para a Ciência e a Tecnologia, Portugal). This study was supported by the Governments of Spain—projects HAR2017-86509 and PGC2018-093925-B-C33 (MCI/AEI/FEDER, UE), Catalonia—project 2017SGR-00011- and France—the International Research Network (IRN 0871 CNRS-INEE): Taphonomy European Network (TaphEN). M. Sanz and J. Daura were supported by Juan de la Cierva (IJCI-2017–33908) and Ramon y Cajal (RYC-2015–17667) postdoctoral grants, respectively. Á. Carrancho gratefully acknowledges financial support from the Junta de Castilla y León (project BU235P18) as well as FEDER funding and project AEI/10.13039/501100011033

Importância do registro em prontuário para implantação de um sistema de informações

Os autores abordam a falta de registro em prontuário e salientam os problemas decorrentes deste procedimento, acarretando prejuízo, em especial no planejamento e na implantação de um sistema de informações, através do qual se obtém uma série de vantagens, tais como: avaliação do trabalho profissional realizado e a possibilidade de determinação dos principais indicadores de saúde de uma população

Sobre a presença de artéria facial em caprino

The AA. reported the occurrence of the right facial artery a half-face of caprine. According to literature, the facial artery is absent in the small ruminants. The traject, distribution and pattern of the facial artery has been related by the AA.Os autores observaram na hemiface direit a de um caprino SRD a presença da artéria facial que, nessa espécie animal, usualmente está ausente. O comportamento e a distribuição da citada artéria, bem como as alterações por ela determinadas no esquema vascular da região são descritas pelos autores

Acute Ischemic Stroke in a Child Successfully Treated with Thrombolytic Therapy and Mechanical Thrombectomy

Acute ischemic stroke in the pediatric population is rare but carries lasting and often lifelong morbidity. Thrombolysis and mechanical thrombectomy are mainstays of care in adults, yet there is very little evidence for these treatments in children. We present the case of a 4-year-old boy with complex congenital heart disease, admitted 30 min after sudden onset of an aphasia and right hemiplegia, scoring 14 on the Pediatric National Institutes of Health Stroke Scale (PedNIHSS). Non-contrast brain computed tomography (CT) showed no evidence of acute ischemia. CT angiogram demonstrated a thrombus in the M1 segment of the left middle cerebral artery. Intravenous recombinant tissue plasminogen activator (rTPA) was infused 3.5 h after onset of symptoms. An improvement was observed in the hour after rTPA, with a PedNIHSS score of 7. Digital subtraction angiography was performed approximately 9 h from the onset of symptoms, showing a complete left M1 occlusion. The patient underwent successful mechanical thrombectomy and was discharged with a PedNIHSS score of 2. This case emphasizes the importance of early recognition to direct children towards rapid diagnosis and hyperacute treatment

Contribution to the study of the internal thoracic veins in dogs

Estudou-se o comportamento da desembocadura das veias torácicas internas em 168 cães S.R.Q., sendo 102 machos e 66 fêmeas, tendo-se verificado cinco modalidades de desembocadura, não relacionadas na literatura.It was studied the patterns of the termination of the internal thoracic veins in 168 dogs, 102 males and 66 females, it was observed five different kinds of terminations no described in the literature