Statistical Mechanics Characterization of Neuronal Mosaics

The spatial distribution of neuronal cells is an important requirement for achieving proper neuronal function in several parts of the nervous system of most animals. For instance, specific distribution of photoreceptors and related neuronal cells, particularly the ganglion cells, in mammal's retina is required in order to properly sample the projected scene. This work presents how two concepts from the areas of statistical mechanics and complex systems, namely the \emph{lacunarity} and the \emph{multiscale entropy} (i.e. the entropy calculated over progressively diffused representations of the cell mosaic), have allowed effective characterization of the spatial distribution of retinal cells.Comment: 3 pages, 1 figure, The following article has been submitted to Applied Physics Letters. If it is published, it will be found online at http://apl.aip.org

Cursos superiores de tecnologia do IFRN – uma análise epistemológica do currículo

Atas do XI Colóquio sobre Questões Curriculares, VII Colóquio Luso-Brasileiro & I Colóquio Luso-Afro-Brasileiro de Questões CurricularesO presente trabalho enquadra-se numa pesquisa em curso no âmbito do doutoramento em Ciências da Educação, na especialidade de Desenvolvimento Curricular. Um dos objetivos da pesquisa é sistematizar e ampliar conhecimentos sobre as bases curriculares dos cursos de tecnologia e problematizar o currículo do ensino superior, considerando o atual contexto social demarcado por complexidades, incertezas e permanentes mudanças. Trata-se de um estudo de natureza qualitativa em que a pesquisa documental é uma das fontes para a recolha de dados. Nesta comunicação incide-se nalguns resultados de uma investigação bibliográfica acerca do currículo dos cursos de tecnologia do IFRN, enfocando o estudo das bases epistemológicas do desenho curricular dos cursos de graduação tecnológica reformulados a partir de 2009 e implementados, na Instituição, em 2012. A primeira parte trata da caracterização e contextualização dos cursos tecnológicos no IFRN, situando-os historicamente e acerca das bases conceituais e metodológicas orientadoras das revisões curriculares do atual contexto institucional. A segunda parte apresenta uma descrição e análise dos princípios organizadores da proposta curricular desses cursos no IFRN, as implicações didáticas e suas articulações com as necessidades formativas dos docentes do ensino superior. Desse modo, espera-se refletir a respeito da proposta curricular dos cursos de graduação tecnológica, a partir da compreensão de uma formação superior integral e produtora de sentidos no âmbito da formação humana, pessoal e profissional, tanto na perspectiva de docentes, quanto de discentes. Visa ainda, ampliar o conhecimento a respeito da concepção e do desenvolvimento curricular nos cursos de graduação tecnológica e contribuir com sistematizações teórico metodológicas que venham a fortalecer o ensino superior e a atuação docente nesse campo de formação. Em síntese, ao se estabelecer relações entre a epistemologia dos conhecimentos teóricos e a epistemologia dos saberes da prática, o estudo busca sistematizar contributos para a construção de uma nova pedagogia universitária.Fundação para a Ciência e a Tecnologia (FCT

A Calibrate Auction-conjoint Experiment to Elicit Consumer Valuation of Sustainable Farming: Is Agro-systems Preservation Relevant?

This paper analyses the role of agro-systems preservation on making food choices. It employs the “Calibrate Auction-Conjoint Valuation method” (CACM), which relates hypothetical conjoint valuation of product attributes with real market behavior using real economic incentives. The paper also allows comparing the hypothetical and nonhypothetical valuations in order to value the difference between the theoretic and the incentive-compatible WTP for a same respondent and within a single experiment. Thus the paper aims at testing for: 1) the internal consistency on people’s behavior towards sustainable agriculture, and 2) the relevance of the price attribute versus agro-ecosystems preservation for a fresh product. Results suggest that Spanish respondents’ valuation of an agricultural product highly depends on the type of system used for its production. Nevertheless, respondents mainly differ between sustainable and non sustainable production, and do not discriminate between organic and integrated systems. In addition, both the price and the protection of the environment are the most important elements taken into account when purchasing. Moreover, consumers tend to overestimate their WTP in hypothetical settings (60% of the sample). Finally, factors such as gender, respondents’ knowledge towards organic production and practices, health concerns, trust on organic marketing agents and risk perception are significant on explaining differences between individual’s hypothetical and non-hypothetical experiments.Consumer/Household Economics, Environmental Economics and Policy,

Distribuição Espacial da Susceptibilidade à Erosão Hídrica nas Bacias das Ribeiras de Picos e Seca (Santiago, Cabo Verde)

Os processos de erosão hídrica em Cabo Verde são os mais marcantes da dinâmica actual das vertentes, pois são os mais comuns e que afectam áreas extensasdurante a curta estação húmida de três meses. A ocorrência de episódios chuvosos concentrados no tempo e com uma evidente irregularidade espacial permitem umaacentuada erosividade das precipitações, marcada por uma forte irregularidade regional. A forte variabilidade das formas de relevo, a diversidade da natureza das unidadesgeológicas e a multiplicidade de ocupação do solo favorecem condições deerodibilidade muito contrastadas no espaço. O objectivo deste trabalho é estabelecer um modelo desusceptibilidade à erosão hídricaem função de factores geomorfológicos (declive, perfil e traçado das vertentes eerodibilidade das unidades litológicas e dos materiais de cobertura), climáticos(intensidade pluviométrica) e de ocupação do solo para as bacias das ribeiras dos Picose Seca. Os resultados foram obtidos com recurso ao ambiente de Sistemas deInformação Geográfica (SIG). Este trabalho surge na sequência de outros já realizadospelos autores, onde se apresentaram as condições de erodibilidade e erosividade paraáreas mais restritas da Ilha de Santiago. O modelo de susceptibilidade à erosão hídrica resultou do cruzamento dos mapas dedeclives, de perfil e do traçado das vertentes, obtidos a partir do modelo digital deterreno (DTM), do mapa geológico, da distribuição espacial da intensidadepluviométrica e da densidade de ocupação do solo, tendo em conta que são estas asprincipais condicionantes de erosão hídrica, referidas pelos autores que estudaram estaregião. Cada um destes mapas foi reclassificado com base numa análise qualitativa dograu de erodibilidade, sendo atribuído um número de ordem a cada classe, em função da sua susceptibilidade à erosão hídrica, conforme foi localmente reconhecido. Verifica-se que as áreas de maior susceptibilidade à erosão hídrica são as do sectorsudeste da bacia da Ribeira Seca e as vertentes dos principais vales da bacia da Ribeira dos Picos, onde se encontram as unidades geológicas mais friáveis, os declives mais acentuados e onde predominam sectores das vertentes de traçado côncavo, a que seassocia pontualmente a mais elevada intensidade pluviométrica.In Cape Verde the hydric erosion is common during the short wet station of three months and is the most dynamic slope process and the most widespread in spatial terms. The rainy events are short and intense, with a great regional irregularity, which allows an high regional variability of the erosivity conditions. The erodibility conditions register also a strong spatial variability due to the landforms contrasts, the diversity lithology and structure of the geological units, and the regional multiplicity of land cover density conditions. The main objective of the study is to develop a geographical model of susceptibility to hydric erosion in Ribeira Seca and Picos basins, based on geomorphological factors (slope angle, profile and tangential curvatures, lithological units and sedimentary cover materials erodibility), climatic one (pluviometric intensity) and land cover density. This study is carried out in the sequence of other ones developed by the authors on more limited areas of Santiago Island or using a more restricted number of factors. The model results from the sum in rank of the maps of spatial distribution of the main factors of hydric erosion, referred by several authors to Santiago: the landform maps obtained from the digital elevation model (DEM); the geological map; the pluviometric intensity spatial distribution; and the land cover density. A hierarchic number of susceptibility to hydric erosion was attributed to each class of these maps, based on qualitative analysis and field work measures evaluation of the relative degree of erodibility or erosivity. The south-east sector of the Ribeira Seca basin and the slopes of the main valleys of the Picos one are the more susceptible to hydric erosion, due to the local friability of the geological unities, the steepness of the slopes, and the frequent sectors of concave curvature, and locally the highest pluviometric intensity

Microbial-based evaluation of foaming events in full-scale wastewater treatment plants by microscopy survey and quantitative image analysis

Activated sludge systems are prone to be affected by foaming occurrences causing the sludge to rise in the reactor and affecting the wastewater treatment plant (WWTP) performance. Nonetheless, there is currently a knowledge gap hindering the development of foaming events prediction tools that may be fulfilled by the quantitative monitoring of AS systems biota and sludge characteristics. As such, the present study focuses on the assessment of foaming events in full-scale WWTPs, by quantitative protozoa, metazoa, filamentous bacteria, and sludge characteristics analysis, further used to enlighten the inner relationships between these parameters. In the current study, a conventional activated sludge system (CAS) and an oxidation ditch (OD) were surveyed throughout a period of 2 and 3 months, respectively, regarding their biota and sludge characteristics. The biota community was monitored by microscopic observation, and a new filamentous bacteria index was developed to quantify their occurrence. Sludge characteristics (aggregated and filamentous biomass contents and aggregate size) were determined by quantitative image analysis (QIA). The obtained data was then processed by principal components analysis (PCA), cross-correlation analysis, and decision trees to assess the foaming occurrences, and enlighten the inner relationships. It was found that such events were best assessed by the combined use of the relative abundance of testate amoeba and nocardioform filamentous index, presenting a 92.9 % success rate for overall foaming events, and 87.5 and 100 %, respectively, for persistent and mild events

Multivariate analysis of walker-assisted ambulation

In an aging society it is extremely important to develop devices which can support and aid the elderly in their daily life. Walkers play an important role, due to the large number of potential users, its simplicity and their ambulatory potential. However, there are no clinical evidences that prove the efficacy of such devices, mainly rollators that present forearm supports. In this context, the authors aim to propose a protocol for an innovative gait analysis that addresses some benefits and limitations of these devices on the rehabilitation process, by addressing a multivariate analysis of spatiotemporal and kinematic gait parameters assessed during normal and assisted ambulation with a walker with forearm supports. For the 3Dreconstruction of the body segments it was used a movement analysis system. Results showed that the effects of assisted gait can be explained through support, energy consumption, posture and balance characteristics. These results are very satisfactory since aspects regarding these characteristics enhance the rehabilitation potential of the use of walkers with forearm supports. These results will be used to advance towards an active robotic walker that will provide for safety and natural manoeuvrability and offer a certain degree of intelligence in assistance and decision-making

CTQ 839: Candidate for the Smallest Projected Separation Binary Quasar

We report the discovery of the new double quasar CTQ 839. This B = 18.3, radio quiet quasar pair is separated by 2.1" in BRIH filters with magnitude differences of delta m_B = 2.5, delta m_R = delta m_I = 1.9, and delta m_H = 2.3. Spectral observations reveal both components to be z = 2.24 quasars, with relative redshifts that agree at the 100 km/s level, but exhibit pronounced differences in the equivalent widths of related emission features, as well as an enhancement of blue continuum flux in the brighter component longward of the Ly alpha emission feature. In general, similar redshift double quasars can be the result of a physical binary pair, or a single quasar multiply imaged by gravitational lensing. Empirical PSF subtraction of R and H band images of CTQ 839 reveal no indication of a lensing galaxy, and place a detection limit of R = 22.5 and H = 17.4 for a third component in the system. For an Einstein-de Sitter cosmology and SIS model, the R band detection limit constrains the characteristics of any lensing galaxy to z_lens >= 1 with a corresponding luminosity of L >~ 5 L_*, while an analysis based on the redshift probability distribution for the lensing galaxy argues against the existence of a z_lens >~ 1 lens at the 2 sigma level. A similar analysis for a Lambda dominated cosmology, however, does not significantly constrain the existence of any lensing galaxy. The broadband flux differences, spectral dissimilarities, and failure to detect a lensing galaxy make the lensing hypothesis for CTQ 839 unlikely. The similar redshifts of the two components would then argue for a physical quasar binary. At a projected separation of 8.3/h kpc (Omega_matter = 1), CTQ 839 would be the smallest projected separation binary quasar currently known.Comment: Latex, 23 pages including 5 ps figures; accepted for publication in A

Honey as a strategy to fight Candida tropicalis in mixed-biofilms with Pseudomonas aeruginosa

Fungal contaminations with Candida species are commonly responsible for several infections, especially when associated to bacteria. The therapeutic approach commonly used is being compromised due to microbial resistances of these microorganisms to antimicrobial agents, especially in biofilm. The use of honey as an antimicrobial agent has been emerging as a valuable solution and proving its potential in planktonic and in biofilm cells. This work aims to assess the effect of different honeys on biofilms of Candida tropicalis and Pseudomonas aeruginosa. The effect of Portuguese heather (PH) and manuka honeys on planktonic growth of Candida was initially evaluated by determination of the minimum inhibitory concentrations (MIC). Then, the same effect was evaluated in mixed biofilms, by colony-forming units numeration and fluorescence microscopy. The combinations of honey plus fluconazole and gentamicin were also tested. The results showed that the honeys tested enabled a great reduction of C. tropicalis, both in planktonic (12.5% and 25% of MIC for PH and manuka) and in biofilm. In polymicrobial biofilms, the use of PH and manuka honeys was revealed to be a promising choice and an alternative treatment, since they were able to reduce cells from both species. No synergistic effect was observed in antimicrobial combinations assays against polymicrobial biofilms.This work was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2019 unit and BioTecNorte operation (NORTE-01-0145-FEDER-000004), funded by the European Regional Development Fund under the scope ofNorte2020—Programa Operacional Regional do Norte and by PTDC/CVT-EPI/4008/2014 project.info:eu-repo/semantics/publishedVersio

Saline stress and cell toxicity evaluation using suspended plant cell cultures of horticultural crops grown in a bioreactor

Crop salt damage consists, usually, of leaf burn and defoliation, and it is associated with accumulation of toxic levels of sodium and/or chloride in leaf cells (Storey and Walker, 1999). The cell and tissue culture are simple biological systems that offer a direct approach to the metabolic changes. The plant cell growth in a controlled environment, as a bioreactor, is a unique tool for cell ion transport studies. Cell suspension culture of citrus cell line was exposed to a medium containing different sodium chloride concentrations (0mM, 42.7mM and 85.5mM). The growth profile of control cells (absence of NaCl) and 85.5mM cells were similar. The lack of inhibition of biomass accumulation, of all tested saline conditions clearly showed that the level of NaCl concentration used was not toxic for the cell metabolism. Also its ability to resist to 85.5mM NaCl can be on evidence that this suspension cel culture might have salt tolerance characteristics