Quality indices for (practical) clustering evaluation

WOS:000271584000004 (Nº de Acesso Web of Science)Clustering quality or validation indices allow the evaluation of the quality of clustering in order to support the selection of a specific partition or clustering structure in its natural unsupervised environment, where the real solution is unknown or not available. In this paper, we investigate the use of quality indices mostly based on the concepts of clusters' compactness and separation, for the evaluation of clustering results (partitions in particular). This work intends to offer a general perspective regarding the appropriate use of quality indices for the purpose of clustering evaluation. After presenting some commonly used indices, as well as indices recently proposed in the literature, key issues regarding the practical use of quality indices are addressed. A general methodological approach is presented which considers the identification of appropriate indices thresholds. This general approach is compared with the simple use of quality indices for evaluating a clustering solution

Culex quinquefasciatus vitellogenesis: morphological and biochemical aspects

The vitellogenic process in Culex quinquefasciatus, which is triggered by a blood meal, involves the synthesis, distribution and storage of the nutrients necessary for embryo development. The fat body of an adult female Cx. quinquefasciatus revealed two cell types: large trophocytes and small, eosinophilic, "oenocyte-like" cells, which show no morphological changes throughout the gonotrophic cycle. Trophocytes, which only begin to synthesise vitellogenin (Vg) 12 h post-blood meal (PBM), undergo a series of morphological changes following engorgement. These changes include the expansion of the rough endoplasmic reticulum (RER) and Golgi complex, which are later destroyed by autophagosomes. At 84 h PBM, trophocytes return to their pre-engorgement morphology. The ovarian follicles of non-blood-fed Cx. quinquefasciatus contain a cluster of eight undifferentiated cells surrounded by follicular epithelium. After engorgement, the oocyte membrane facing the perioocytic space increases its absorptive surface by microvilli development; large amounts of Vg and lipids are stored between 24 and 48 h PBM. Along with yolk storage in the oocyte, follicular cells exhibit the development of RER cisternae and electron-dense granules begin to fill the perioocytic space, possibly giving rise to endochorion. Later in the gonotrophic cycle, electron-dense vesicles, which are possible exochorion precursors, fuse at the apical membrane of follicular cells. This fusion is followed by follicular cell degeneration.FAPESPCoordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES

PRODUTOS DEFEITUOSOS: QUANDO AS BONECAS GANHAM INDIVIDUALIDADE

A figura do robô é frequentemente utilizada na ficção científica para abordar as relações entre subjetividade e tecnologia, e as dificuldades da humanidade frente a mudanças de paradigmas, como acontece nos contos “Dolly” (2011), de Elizabeth Bear, e “Mika Model” (2016), de Paolo Bacigalupi. Este artigo pretende analisar ambos os contos, traçando as relações humano/máquina que eles representam, passando por questões que atravessam as noções de soberania. Será investigado também até que ponto o pós-humanismo propõe uma revisão de certos conceitos e valores através das obras selecionadas

Heterotic String Compactifications on Half-flat Manifolds II

In this paper, we continue the analysis of heterotic string compactifications on half-flat mirror manifolds by including the 10-dimensional gauge fields. It is argued, that the heterotic Bianchi identity is solved by a variant of the standard embedding. Then, the resulting gauge group in four dimensions is still E6 despite the fact that the Levi-Civita connection has SO(6) holonomy. We derive the associated four-dimensional effective theories including matter field terms for such compactifications. The results are also extended to more general manifolds with SU(3) structure.Comment: 31 page

Poder Calorífico da Casca de Arroz, Caroço de Pêssego, Serragem de Eucalipto e de seus Produtos de Pirólise

The Higher Heating Value (HHV) of rice husks, peach stones andeucalyptus sawdust was determined, as well as of the resulting bio-oils andresidual chars from low temperature conversion process. Products yields forbio oils varied from 16 to 26%, and for solid residue, from 38 to 48%. HHV of3,900, 2,600 and 4,100 cal/g were measured for rice husks biomass, its residualchar and bio-oil; 4,100, 5,800 and 4,000 cal/g, for eucalyptus sawdust, its charand bio oil; 3.,400, 3,200 e 3,900 cal/g, for peach stones, its char and bio oil,respectively. These values show that biomasses and pyrolysis products canbe considered as renewable energy sources, clean and neutral to global warming.Determinou-se o poder calorífico superior (PCS) das biomassas:casca de arroz, caroço de pêssego, serragem de eucalipto, e dos bioóleos eresíduos carbonosos correspondentes, obtidos por conversão térmica a baixatemperatura. Rendimentos de bioóleo entre 16% e 26%, e, de resíduo carbonoso,entre 38% e 48%, foram obtidos na pirólise. Valores de Poder Calorífico de3.900, 2.600 e 4.100 cal/g foram medidos para a casca de arroz, seu carvão e óleode pirólise; 4.100, 5.800 e 4.000 cal/g, para serragem de eucalipto, seu carvão eóleo de pirólise; 3.400, 3.200 e 3.900 cal/g, para caroço de pêssego, seu carvãoe bioóleo, respectivamente. Estes valores demonstram que as biomassas e osseus produtos de pirólise podem ser considerados fontes renováveis de energia,limpas e neutras quanto ao fenômeno de aquecimento global.Palavras chave: biomassa, pirólise, poder calorífico superior

New insights on the impacts of e-waste towards marine bivalves: the case of the rare earth element Dysprosium

With the technological advances and economic development, the multiplicity and wide variety of applications of electrical and electronic equipment have increased, as well as the amount of end-of-life products (waste of electrical and electronic equipment, WEEE). Accompanying their increasing application, there is an increasing risk to aquatic ecosystems and inhabiting organisms. Among the most common elements present in WEEE are rare earth elements (REE) such as Dysprosium (Dy). The present study evaluated the metabolic and oxidative stress responses of mussels Mytilus galloprovincialis exposed to an increasing range of Dy concentrations, after a 28 days experimental period. The results obtained highlighted that Dy was responsible for mussel’s metabolic increase associated with glycogen expenditure, activation of antioxidant and biotransformation defences and cellular damage, with a clear loss of redox balance. Such effects may greatly impact mussel’s physiological functions, including reproduction capacity and growth, with implications for population conservation. Overall the present study pointed out the need for more research on the toxic impacts resulting from these emerging pollutants, especially towards marine and estuarine invertebrate species.publishe

Development of pH-Sensitive magnetoliposomes containing shape anisotropic nanoparticles for potential application in combined cancer therapy

Late diagnosis and systemic toxicity associated with conventional treatments make oncological therapy significantly difficult. In this context, nanomedicine emerges as a new approach in the prevention, diagnosis and treatment of cancer. In this work, pH-sensitive solid magnetoliposomes (SMLs) were developed for controlled release of the chemotherapeutic drug doxorubicin (DOX). Shape anisotropic magnetic nanoparticles of magnesium ferrite with partial substitution by calcium (Mg0.75Ca0.25Fe2O4) were synthesized, with and without calcination, and their structural, morphological and magnetic properties were investigated. Their superparamagnetic properties were evaluated and heating capabilities proven, either by exposure to an alternating magnetic field (AMF) (magnetic hyperthermia) or by irradiation with near-infrared (NIR) light (photothermia). The Mg0.75Ca0.25Fe2O4 calcined nanoparticles were selected to integrate the SMLs, surrounded by a lipid bilayer of DOPE:Ch:CHEMS (45:45:10). DOX was encapsulated in the nanosystems with an efficiency above 98%. DOX release assays showed a much more efficient release of the drug at pH = 5 compared to the release kinetics at physiological pH. By subjecting tumor cells to DOX-loaded SMLs, cell viability was significantly reduced, confirming that they can release the encapsulated drug. These results point to the development of efficient pH-sensitive nanocarriers, suitable for a synergistic action in cancer therapy with magnetic targeting, stimulus-controlled drug delivery and dual hyperthermia (magnetic and plasmonic) therapy.This work was funded by the Portuguese Foundation for Science and Technology (FCT) within the framework of the Strategic Funding of Research Units UIDB/04650/2020 (CF-UM-UP), UIDB/00319/2020 (ALGORITMI), UIDB/04077/2020 (MEtRICs), UIDB/04436/2020 (CMEMS) and UIDB/00511/2020 (LEPABE). FCT, POCI, FEDER and NORTE2020 are acknowledged for funding through research projects PTDC/QUI-QFI/28020/2017, EXPL/EMD-EMD/0650/2021, PTDC/EEI-EEE/2846/2021 and NORTE-01-0145-FEDER-000054. MINECO (Spain) is acknowledged for project MAT2016-76824-C3-2-R. B.D.C. and V.M.C. acknowledge FCT for PhD grants SFRH/BD/141936/2018 (B.D.C.) and UI/BD/151028/2021 (V.M.C.). R.O.R. thanks FCT for contract 2020.03975.CEECIND

Brain levels of nonapeptides in four labrid fish species with different levels of mutualistic behavior

a b s t r a c t There is strong evidence that brain nonapeptides are implicated as modulators of a wide array of social and reproductive behaviors in fishes. However, the question remains, as to whether there is a link between the distribution of active nonapeptides across brain regions and fishes specific behavioral phenotypes. To explore this link we compared the nonapeptides' profile across the brains of fishes representing different degrees of mutualistic behavior (here: cleaning behavior). Herein we studied the quantitative distribution of both nonapeptides, arginine vasotocin (AVT) and isotocin (IT), in the brains of four species of fish belonging to the family Labridae: two are obligatory cleaners throughout their entire life (Labroides dimidiatus and Labroides bicolor), one species is a facultative cleaner (Labropsis australis; juveniles are cleaners and adults are corallivorous), and one is a non-cleaner species, corallivorous throughout its entire life (Labrichthys unilineatus). The biologically available AVT and IT concentrations were measured simultaneously in distinct brain macro-areas: forebrain, optic tectum, cerebellum and brain stem, using liquid chromatography-tandem mass spectrometry (LC-MS/MS). We showed that the levels of both AVT and IT varied significantly across species, as measured in the whole brain or in the specific macro-areas. Significantly higher AVT concentrations in the cerebellum which were found in the obligate cleaners seemed to be related to expression of mutualistic behavior. On the other hand, the higher levels of brain IT in the non-cleaner L. unilineatus suggested that these might be linked to the development of sexual dimorphism, which occurs only in this non-cleaner species

Fixed-Dose Artesunate-Amodiaquine Combination vs Chloroquine for Treatment of Uncomplicated Blood Stage P. vivax Infection in the Brazilian Amazon: An Open-Label Randomized, Controlled Trial

BACKGROUND: Despite increasing evidence of the development of Plasmodium vivax chloroquine (CQ) resistance, there have been no trials comparing its efficacy with that of artemisinin-based combination therapies (ACTs) in Latin America. METHODS: This randomized controlled trial compared the antischizontocidal efficacy and safety of a 3-day supervised treatment of the fixed-dose combination artesunate-amodiaquine Winthrop(R) (ASAQ) versus CQ for treatment of uncomplicated P. vivax infection in Manaus, Brazil. Patients were followed for 42 days. Primary endpoints were adequate clinical and parasitological responses (ACPR) rates at day 28. Genotype-adjustment was performed. RESULTS: From 2012 to 2013, 380 patients were enrolled. In the per-protocol (PP) analysis, adjusted-ACPR was achieved in 100% (165/165) and 93.6% (161/172) of patients in the ASAQ and CQ arm (difference 6.4%, 95% CI 2.7%; 10.1%) at day 28 and in 97.4% (151/155) and 77.7% (129/166), respectively (difference 19.7%, 95% CI 12.9%; 26.5%), at day 42. Apart from ITT D28 assessment, superiority of ASAQ on ACPR was demonstrated. ASAQ presented faster clearance of parasitaemia and fever. Based on CQ blood level measurements, CQ resistance prevalence was estimated at 11.5% (95% CI: 7.5-17.3) up to day 42. At least one emergent adverse event (AE) was recorded for 79/190 (41x6%) in the ASAQ group and for 85/190 (44x7%) in the CQ group. Both treatments had similar safety profiles. CONCLUSIONS: ASAQ exhibited high efficacy against CQ resistant P. vivax and is an adequate alternative in the study area. Studies with an efficacious comparator, longer follow-up and genotype-adjustment can improve CQR characterization