Detection of outliers in multivariate data: a method based on clustering and robust estimators

Outlier identification is important in many applications of multivariate analysis. Either because there is some specific interest in finding anomalous observations or as a pre-processing task before the application of some multivariate method, in order to preserve the results from possible harmful effects of those observations. It is also of great interest in supervised classification (or discriminant analysis) if, when predicting group membership, one wants to have the possibility of labelling an observation as does not belong to any of the available groups. The identification of outliers in multivariate data is usually based on Mahalanobis distance. The use of robust estimates of the mean and the covariance matrix is advised in order to avoid the masking effect (Rousseeuw and Leroy, 1985; Rousseeuw and von Zomeren, 1990; Rocke and Woodruff, 1996; Becker and Gather, 1999). However, the performance of these rules is still highly dependent of multivariate normality of the bulk of the data. The aim of the method here described is to remove this dependence

Isolation and characterization of Faecalibacterium prausnitzii from calves and piglets.

The goal of our study was to isolate and characterize Faecalibacterium prausnitzii from fecal samples of healthy calves and piglets, in order to develop a novel probiotic for livestock animals. We identified 203 isolates of Faecalibacterium sp., which were clustered in 40 genetically distinct groups. One representative isolate from each cluster was selected for further characterization. The concentrations of the short chain fatty acids (SCFA) acetate, butyrate, propionate and isobutyrate in the culture media were measured by gas chromatography. We observed reduction in the concentration of acetate followed by concomitant increase in the concentration of butyrate, suggesting that the isolates were consuming acetate present in the media and producing butyrate. Butyrate production correlated positively with bacterial growth. Since butyrate has many benefits to the colonic epithelial cells, the selection of strains that produce higher amounts of butyrate is extremely important for the development of this potential probiotic. The effect of pH and concentration of bile salts on bacterial growth was also evaluated in order to mimic the conditions encountered by F. prausnitzii in vivo. The optimal pH for growth ranged between 5.5 and 6.7, while most isolates were inhibited by of the lowest concentration of bile salts tested (0.1%). Antimicrobial resistance profile showed that most isolates of Faecalibacterium sp. were resistant against ciprofloxacin and sulfamethoxazole-trimethoprim. More than 50% of the isolates were resistant to tetracycline, amikacin, cefepime and cefoxitin. A total of 19 different combinations of multidrug resistance were observed among the isolates. Our results provide new insights into the cultural and physiological characteristics of Faecalibacterium prausnitzii illustrating large variability in short chain fatty acid production, in vitro growth, sensitivity to bile salts, and antibiotic resistance and suggesting that future probiotic candidates should be carefully studied before elected for in vivo studies

Thin-layer nanofiltration membranes using engineered biopolymers for seawater desalination pre-treatment processes

Nowadays water demand already exceeds supply and water scarcity is a global problem. So it is necessary to develop novel technologies to be able to use poorer quality source waters for drinking water production. Once considered as an expensive, ultimate solution for water supply, desalination is becoming affordable. The two most commonly used seawater desalination methods are Multi-stage Flash Distillation (MSF) and Seawater Reverse Osmosis (SWRO). SWRO is less energy demanding compared to MSF, which makes it economically attractive. However there is no backpulsing of the expensive and delicate reverse osmosis (RO) membranes with air or water, so they are susceptible to fouling, causing the loss of their performance. Therefore cleaning the feed water to the highest level possible by nanofiltration, before it reaches the RO membranes would highly increase the efficiency of the process. Nanofiltration (NF) as a feed pre-treatment step is a pressure driven membrane separation process that takes place on a selective layer formed by a semipermeable membrane with properties between RO and ultrafiltration. The objective of this project is the developement of highly efficient thin-film composite (TFC) membranes for SWRO pre-treatment processes based on low-fouling cyanobacterial extracellular polymeric substances (EPS). TFC membranes combine high flux and mechanical strenght, and they are expected to be the key components of any water purification technology in the future. Cyanobacterial EPS are complex heteropolysaccharides with putative antimicrobial and antiviral properties and a particular affinity to bind metal ions [1,2].Within this work, the unicellular N2-fixing marine cyanobacterium Cyanothece sp. CCY 0110 was chosen for RPS production, since it is among the most efficient released polysaccharide (RPS) producers and the polymer has been previously extensively characterised [3]. RPS was produced by growing Cyanothece CCY 0110 in 10L bioreactors, in conditions previously defined and the polymer was isolated following the standard methodology [3]. A polyvinyl alcohol (PVA) / cyanobacterial EPS blend nanofibrous membranes were fabricated by electrospinning using polyvinylidene fluoride (PVDF) as a basal membrane, in order to obtain thin-layer composite nanofiltration membranes. The production of the nanofibers using EPS and PVA as plasticizer in different ratios was produced in a NF-103 MECC Nanon electrospinning equipment with an applied electric field between 15 and 25 kV and a flow of 0,2 mL/h. Morphological, mechanical, chemical and thermal characterization of the electrospun fibers deposited on the basal membranes, were evaluated by atomic force microscopy (AFM), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), dynamical and mechanical analysis (DMA), thermogravimetry (TGA) and differential scanning calorimetry (DSC). The AFM and SEM results show the presence of fibers with dimensions between 54 and 121 nm with low bead formation. In the EDS analysis presence of sulfur elements was observed confirming the inclusion of EPS in the nanofibers. The morphology and diameter of the nanofibers were mainly affected by the concentration of the blend solution and the weight ratio of the blend, respectively. The best PVA/EPS nanofibers were achieved in a ratio of 12 % PVA and 0.4 % EPS. The solution conductivity was ranging 1500 to 3500 μS/cm with a viscosity of about 100 to 500 cP. The DMA results confirmed the miscibility of PVA/EPS blends. The elastic modulus of the nanocomposite mats increased significantly as a consequence of the reinforcing effect of EPS. Thermal and mechanical analysis demonstrated that there were strong intermolecular hydrogen bonds between the molecules EPS-PVA in the blends. The heat-treated electrospun blended membranes showed better tensile mechanical properties when compared with PVA alone, and resisted more against disintegration. A lab-scale nanofiltration was performed in a bench stainless steel Sterlitech tangential flow stirred cell (200 mL) connected to an air pressure system that allow pressure driven filtration up to 10 BAR. Bactericidal activity and biofilm formation were tested using Escherichia coli and Sthaphylococcus aureus as pathogenic microorganisms

Mito-nuclear sequencing is paramount to correctly identify sympatric hybridizing fishes

Background. Hybridization may drive speciation and erode species, especially when intrageneric sympatric species are involved. Five sympatric Luciobarbus species—Luciobarbus sclateri (Günther, 1868), Luciobarbus comizo (Steindachner, 1864), Luciobarbus microcephalus (Almaça, 1967), Luciobarbus guiraonis (Steindachner, 1866), and Luciobarbus steindachneri (Almaça, 1967)—are commonly identified in field surveys by diagnostic morphological characters. Assuming that i) in loco identification is subjective and observer-dependent, ii) there is previous evidence of interspecific hybridization, and iii) the technical reports usually do not include molecular analyses, our main goal was to assess the concordance between in loco species identification based on phenotypic characters with identifications based on morphometric indices, mtDNA only, and a combination of mito-nuclear markers. Materials and methods. Specimens of Luciobarbus from six Guadiana River sub-basins were collected and sequenced for the cytochrome b and beta-actin genes. For comparative purposes, samples of Luciobarbus from other 12 river basins were also used. Four levels of taxonomical identification were conducted based on: identification made in the field (in loco identification), cytb gene only, beta-actin gene only, and mito-nuclear combined genomes. Results. Results showed that interspecific hybridization seems to be high (around 41%) and likely favoured by non-random mating and the loss of fluvial connectivity. About 34% of the hybrids showed mito-nuclear discordance. Misidentifications were frequent when only phenotypic characters are considered, and the use of a single mitochondrial gene is not sufficient: the use of two mito-nuclear markers showed that around 82% of the in loco identifications based on the phenotype were not correct. Conclusion. Incorrect species assignment likely generated biased results in previous studies on the biology and ecology of Guadiana barbels and in the assignment of conservation status and, consequently, on the establishment of conservation management measuresinfo:eu-repo/semantics/publishedVersio

Parent's reports of lexical and grammatical aspects of toddlers's language in European Portuguese: developmental trends, age and gender differences

The results from a large-scale study on toddlers’ language acquisition in European Portuguese are presented. Toddlers’ lexical and grammatical competencies were assessed using the MacArthur–Bates Communicative Development Inventory: Words and Sentences. The results, based on 3012 reports completed by parents, indicate an increase in the lexical size and on five measures of grammatical development (production of regular morphology, irregular morphology, over-regularizations, mean length of utterances and sentence complexity) across age groups. A main effect of gender was found for lexical size, production of regular and irregular morphology, production of over-regularizations and sentence complexity, with girls obtaining overall higher scores than boys. All lexical and grammatical development measures are positively correlated, even after controlling for age and gender effects. These findings are discussed in terms of their consistency with those obtained for other languages.CiPsi - Psychology Research Centre, Uminho (UID/PSI/ 01662/2013), PortugalCIEC – Research Centre on Child Studies, IE, UMinho (FCT R&D unit 317), Portugalinfo:eu-repo/semantics/publishedVersio

Lexical, morphological and syntactic development in toddlers between 16 and 30 months old: a comparison across European Portuguese and Galician

The main aims of this study were to investigate the relationship between the lexical size and the emergence of morphological and syntactic markers in toddlers between the ages of 16 and 30 months and to compare these results between Galician and European Portuguese. Parents of 3012 Portuguese toddlers and those of 1081 Galician toddlers completed the MacArthur–Bates Communicative Development Inventory: Words and Sentences. The results indicated that the number of words, the ability to combine words and the number of different morphemes produced increased with age. The ability to combine words was used as an indicator of syntactic development; this ability was also associated with the toddlers’ lexical size. In both samples, gender morphemes seemed to be the first to have their production generalized, followed by the plural and the past participle. The production of gender morphemes was accompanied by a small lexical size, whereas the imperfect tense and the person mark onset were associated with large lexical sizes. The implications of these results for charting the continuity between lexical, morphological and syntactical development are discussed.CiPsi - Psychology Research Centre, Uminho (UID/PSI/ 01662/2013), Portugal. National Funds through the FCT (Foundation for Science and Technology) and co-financed by European Regional Development Funds (FEDER) through the the National Strategic Reference Framework (QREN) - FCOMP- 01-0124-FEDER-029556 and through the Competitiveness and Internationalization Operational Program (POCI) with the references and POCI-01-0145-FEDER-007562CIEC – Research Centre on Child Studies, IE, UMinho (FCT R&D unit 317), Portugal. BPD/102549/2014info:eu-repo/semantics/publishedVersio

Translation, adaptation and validation of the amputation experience scales (TAPES-R-PT)

RESUMO: A Trinity Amputation and Prosthetics Experience Scale-revised (TAPES-R) permite uma avaliação multidimensional do ajustamento psicossocial à prótese. Este estudo apresenta a tradução, adaptação, validade e confiabilidade da versão portuguesa do TAPES-R-PT para pacientes amputados sem prótese. Participaram neste estudo 144 pacientes com Diabetes Mellitus Tipo 2 e amputação do membro inferior, na sua maioria do sexo masculino (70,8%) com uma média de idade de 66 anos (DP=10,7). A Análise Fatorial Confirmatória sugeriu um bom ajustamento num modelo com três fatores no Ajustamento Psicossocial (Ajustamento Geral, Ajustamento Social, Ajustamento às Limitações), e um fator unidimensional na Escala de Restrição nas Atividades. Os valores de consistência interna revelaram-se adequados e as correlações significativas com o SF-36 e o HADS demonstraram evidências de validade convergente. A versão portuguesa da TAPES-R-PT revela-se um instrumento prático, compreensível e breve para ser usado na prática clínica, durante as avaliações de rotina e em contexto de investigação no sentido de avaliar e monitorizar o processo de ajustamento à amputação.The Trinity Amputation and Prosthetics Experience Scale-revised (TAPES-R) allows a multidimensional assessment of the psychosocial adjustment to the prosthesis. This study presents the translation, adaptation, validity and reliability of the Portuguese version of TAPES-R-PT for amputees without prosthesis. Participated in this study 144 patients with Type 2 Diabetes Mellitus and lower limb amputation, mostly male gender (70.8%) with a mean age of 66 years old (SD=10.7). Confirmatory Factor Analysis suggested a good fit in a model with three factors in Psychosocial Adjustment (General Adjustment, Social Adjustment, Adjustment to Limitations), and a one-dimensional factor in Activity Restriction Scale. The internal consistency values were adequate and the significant correlations with SF-36 and HADS showed evidence of convergent validity. The Portuguese version of TAPES-R-PT proves to be a useful, understandable and brief instrument to be used in clinical practice, during routine assessments and in the context of research in order to assess and monitor the amputation adjustment process.Fundação para a Ciência e Tecnologia e pelo Ministério da Ciência, Tecnologia e Ensino Superior, através de fundos nacionais e cofinanciado pelo FEDER através do COMPETE2020 no âmbito do Acordo de Parceria PT2020 (POCI-01-0145-FEDER-007653). Este trabalho foi financiado por uma bolsa (SFRH / BD / 87704/2012) da Fundação para a Ciência e Tecnologi