1,060 research outputs found

    Accounting for covariate information in the scale component of spatio-temporal mixing models

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    Spatio-temporal processes in the environmental science are usually assumed to follow a Gaussian process, possibly after some transformation. Gaussian processes might not be appropriate to handle the presence of outlying observations. Our proposal is based on the idea of modelling the process as a scale mixture between a Gaussian and log-Gaussian process. And the novelty is to allow the scale process to vary as a function of covariates. The resultant model has a nonstationary covariance structure in space. Moreover, the resultant kurtosis varies with location, allowing the time series at each location to have different distributions with different tail behaviour. Inference procedure is performed under the Bayesian framework. The analysis of an artificial dataset illustrates how this proposal is able to capture heterogeneity in space caused by dependence on some spatial covariate or by a transformation of the process of interest. Furthermore, an application to maximum temperature data observed in the Spanish Basque country illustrates the effects of altitude in the variability of the process and how our proposed model identifies this dependence through parameters which can be interpreted as regression coefficients in the variance model

    A Systematic Review of Algorithms with Linear-time Behaviour to Generate Delaunay and Voronoi Tessellations

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    Triangulations and tetrahedrizations are important geometrical discretization procedures applied to several areas, such as the reconstruction of surfaces and data visualization. Delaunay and Voronoi tessellations are discretization structures of domains with desirable geometrical properties. In this work, a systematic review of algorithms with linear-time behaviour to generate 2D/3D Delaunay and/or Voronoi tessellations is presented

    Comparing Mixed & Integer Programming vs. Constraint Programming by solving Job-Shop Scheduling Problems

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    Scheduling is a key factor for operations management as well as for business success. From industrial Job-shop Scheduling problems (JSSP), many optimization challenges have emerged since de 1960s when improvements have been continuously required such as bottlenecks allocation, lead-time reductions and reducing response time to requests.  With this in perspective, this work aims to discuss 3 different optimization models for minimizing Makespan. Those 3 models were applied on 17 classical problems of examples JSSP and produced different outputs.  The first model resorts on Mixed and Integer Programming (MIP) and it resulted on optimizing 60% of the studied problems. The other models were based on Constraint Programming (CP) and approached the problem in two different ways: a) model CP1 is a standard IBM algorithm whereof restrictions have an interval structure that fail to solve 53% of the proposed instances, b) Model CP-2 approaches the problem with disjunctive constraints and optimized 88% of the instances. In this work, each model is individually analyzed and then compared considering: i) Optimization success performance, ii) Computational processing time, iii) Greatest Resource Utilization and, iv) Minimum Work-in-process Inventory. Results demonstrated that CP-2 presented best results on criteria i and ii, but MIP was superior on criteria iii and iv and those findings are discussed at the final section of this work

    Identification of Alkaloids from Hippeastrum aulicum (Ker Gawl.) Herb.(Amaryllidaceae) Using CGC-MS and Ambient Ionization Mass Spectrometry (PS-MS and LS-MS)

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    Amaryllidaceae alkaloids are well-known isoquinolines which have demonstrated a wide range of biological activities such as antiviral, anticancer, acetylcholinesterase inhibition, antimalarial, among others. Mass spectrometry (MS) studies based on capillary gas chromatography (CGC), paper spray (PS), and leaf spray (LS) ionization were carried out for alkaloid investigation of the native Brazilian species Hippeastrum aulicum, along with nuclear magnetic resonance (NMR) techniques. Thirty-one alkaloids were identified including the new compound haemanthamine N-oxide. The results from PS- and LS-MS techniques were consistent with those observed in CGC-MS analysis. To the best of our knowledge, it is the first study combining NMR, CGC-MS and the ambient ionization-mass spectrometry (PS- and LS-MS) on Amaryllidaceae plants

    Structure of an Odorant-Binding Protein from the Mosquito Aedes aegypti Suggests a Binding Pocket Covered by a pH-Sensitive “Lid”

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    Background: The yellow fever mosquito, Aedes aegypti, is the primary vector for the viruses that cause yellow fever, mostly in tropical regions of Africa and in parts of South America, and human dengue, which infects 100 million people yearly in the tropics and subtropics. A better understanding of the structural biology of olfactory proteins may pave the way for the development of environmentally-friendly mosquito attractants and repellents, which may ultimately contribute to reduction of mosquito biting and disease transmission. Methodology: Previously, we isolated and cloned a major, female-enriched odorant-binding protein (OBP) from the yellow fever mosquito, AaegOBP1, which was later inadvertently renamed AaegOBP39. We prepared recombinant samples of AaegOBP1 by using an expression system that allows proper formation of disulfide bridges and generates functional OBPs, which are indistinguishable from native OBPs. We crystallized AaegOBP1 and determined its three-dimensional structure at 1.85 angstrom resolution by molecular replacement based on the structure of the malaria mosquito OBP, AgamOBP1, the only mosquito OBP structure known to date. Conclusion: The structure of AaegOBP1 (= AaegOBP39) shares the common fold of insect OBPs with six alpha-helices knitted by three disulfide bonds. A long molecule of polyethylene glycol (PEG) was built into the electron-density maps identified in a long tunnel formed by a crystallographic dimer of AaegOBP1. Circular dichroism analysis indicated that delipidated AaegOBP1 undergoes a pH-dependent conformational change, which may lead to release of odorant at low pH (as in the environment in the vicinity of odorant receptors). A C-terminal loop covers the binding cavity and this ""lid"" may be opened by disruption of an array of acid-labile hydrogen bonds thus explaining reduced or no binding affinity at low pH.National Science Foundation (NSF) [0918177]National Institutes of Health (NIH) NIAIDBrazilian National Institutes of Science and Technology: Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) [573607/2008-7]Brazilian National Institutes of Science and Technology: FAPESP [08/57910-0

    Flora da Serra do Cipó, Minas Gerais: Amaryllidaceae

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    Neste trabalho são apresentadas as espécies de Amaryllidaceae da Serra do Cipó, Minas Gerais, Brazil. Amaryllidaceae é representada na área por 4 espécies pertencentes a 3 gêneros: Habranthus datensis Ravenna, Hippeastrum glaucescens (Mart.) Herb., H. puniceum (Lam.) Kuntze e Rhodophiala cipoana Ravenna. São apresentados chave para os gêneros e espécies, descrições, ilustrações e comentários.This work presents the species of Amaryllidaceae of the Serra do Cipó, Minas Gerais state, Brazil. Amaryllidaceae is represented in the area by 4 species of 3 genera: Habranthus datensis Ravenna, Hippeastrum glaucescens (Mart.) Herb., H. puniceum (Lam.) Kuntze and Rhodophiala cipoana Ravenna. A key to the genera and species, descriptions, illustrations and comments are provided

    Exploring Lip Segmentation Techniques in Computer Vision: A Comparative Analysis

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    Lip segmentation is crucial in computer vision, especially for lip reading. Despite extensive face segmentation research, lip segmentation has received limited attention. The aim of this study is to compare state-of-the-art lip segmentation models using a standardized setting and a publicly available dataset. Five techniques, namely EHANet, Mask2Former, BiSeNet V2, PIDNet, and STDC1, are qualitatively selected based on their reported performance, inference time, code availability, recency, and popularity. The CelebAMask-HQ dataset, comprising manually annotated face images, is used to fairly assess the lip segmentation performance of the selected models. Inference experiments are conducted on a Raspberry Pi4 to emulate limited computational resources. The results show that Mask2Former and EHANet have the best performances in terms of mIoU score. BiSeNet V2 demonstrate competitive performance, while PIDNet excels in recall but has lower precision. Most models present inference time ranging from 1000 to around 3000 milliseconds on a Raspberry Pi4, with PIDNet having the lowest mean inference time. This study provides a comprehensive evaluation of lip segmentation models, highlighting their performance and inference times. The findings contribute to the development of lightweight techniques and establish benchmarks for future advances in lip segmentation, especially in IoT and edge computing scenarios

    Cenas de uma vida ingênua: escravidão e infância em Uberaba (1871-1888)

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    Novos estudos sobre a Escravidão no Brasil estão sendo elaborados com uma nova abordagem historiográfica. Em Uberaba, a escravidão conviveu como desenvolvimento da pequena urbe, de uma região conhecida até então, como o Sertão da Farinha Podre. No intuito de levantar cenas desse cotidiano cativo em Uberaba, partimos para um levantamento bibliográfico sobre a temática escravidão e história de Uberaba. Amparados pela História Cultural, buscamos nas fontes do Arquivo Público de Uberaba, documentos que nos possibilitassem realizar esse levantamento. Uma criança nos chamou a atenção, Alexandrina, julgada e condenada aos “sete passo oito” anos de idade. E no seu processo de julgamento fica claro um mascaramento para os castigos e explorações sofridas pelas crianças negras, filhas de pais escravos, libertadas pela Lei do Ventre Livre.SCENES OF AN INGENUOUS LIFE: SLAVERY AND INFANCY INUBERABA (1871-1888)Abstract: New studies on slavery in Brazil are being developed with a new historiographical approach. Uberaba, slavery coexisted with the development of small metropolis, a region previously known as the “Sertão da Farinha Podre”. In order to raise this everyday scenes captive in Uberaba, we went to a literature on the theme of slavery and the history of Uberaba. Supported by the Cultural History, seek the sources of the “Arquivo Público de Uberaba”, documents allowing us to conduct this survey. One child drew our attention, Alexandrina, tried and sentenced to “seven step eight” years old. And in the process of trial is clearly a punishment for blinding and exploitation suffered by black children, daughters of slaves, freed by the “Lei do Ventre Livre”

    Methicillin-resistant Staphylococcus aureus (MRSA) carriage in a dermatology unit

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    OBJECTIVE: The aim of this study was to characterize Staphylococcus aureus (MRSA) carriage in a dermatology unit. METHODS: This was a prospective and descriptive study. Over the course of 26 weeks, surveillance cultures were collected weekly from the anterior nares and skin of all patients hospitalized in a 20-bed dermatology unit of a tertiary-care hospital. Samples from healthcare workers (HCWS) were cultured at the beginning and end of the study. Colonized patients were put under contact precautions, and basic infection control measures were enforced. Staphylococcus aureus colonization pressure was determined monthly. Colonized and non-colonized patients were compared, and isolates were evaluated for antimicrobial susceptibility, SCCmec type, virulence factors, and type. RESULTS: Of the 142 patients evaluated, 64 (45%) were colonized by MRSA (39% hospital acquired; 25% community acquired; 36% indeterminate). Despite isolation precautions, hospital-acquired Staphylococcus aureus occurred in addition to the continuous entry of Staphylococcus aureus from the community. Colonization pressure increased from 13% to 59%, and pemphigus and other bullous diseases were associated with MRSA colonization. Eleven out of 71 HCWs (15%) were Staphylococcus aureus carriers, although only one worker carried a persistent clone. Of the hospital-acquired MRSA cases, 14/28 (50%) were SCCmec type IV (3 PFGE types), 13 were SCCmec type III (46%), and one had an indeterminate type. These types were also present among the community-acquired Staphylococcus aureus isolates. SSCmec type IV isolates were shown to be more susceptible than type III isolates. There were two cases of bloodstream infection, and the pvl and tst virulence genes were absent from all isolates. CONCLUSIONS: Dermatology patients were colonized by community- and hospital-acquired Staphylococcus aureus. Half of the nosocomial Staphylococcus aureus isolates were SCCmec type IV. Despite the identification of colonized patients and the subsequent contact precautions and room placement, Staphylococcus aureus colonization continued to occur, and colonization pressure increased. Pemphigus and other bullous diseases were associated with Staphylococcus aureus
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