The friendship paradox in scale-free networks

Our friends have more friends than we do. That is the basis of the friendship paradox. In mathematical terms, the mean number of friends of friends is higher than the mean number of friends. In the present study, we analyzed the relationship between the mean degree of vertices (individuals), , and the mean number of friends of friends, , in scale-free networks with degrees ranging from a minimum degree (k_min) to a maximum degree (k_max). We deduced an expression for - for scale-free networks following a power-law distribution with a given scaling parameter (alpha). Based on this expression, we can quantify how the degree distribution of a scale-free network affects the mean number of friends of friends.Comment: 9 pages, 2 figure

Cana-de-açúcar cultivada num latossolo que recebeu lodo de esgoto e vinhaça: teores de nitrogênio no solo e na planta

O lodo de esgoto é um resíduo obtido em Estações de Tratamento de Esgoto. A vinhaça constitui-se no principal efluente das destilarias de álcool. A principal diferença entre ambos está nos conteúdos de nitrogênio (N) e potássio (K), sendo o lodo de esgoto pobre em K e a vinhaça pobre em N. O objetivo deste trabalho foi avaliar o efeito do lodo de esgoto e da vinhaça sobre o nitrogênio no sistema solo-planta e os reflexos na produtividade da cana-de-açúcar por dois anos consecutivos. O experimento foi conduzido em um Latossolo Vermelho Amarelo Distrófico plintico, localizado no Município de Pontal, SP. A cultivar de cana-de-açúcar testada foi a SP81-3250. Os fatores de estudo foram três resíduos (lodo de esgoto, vinhaça e lodo de esgoto+vinhaça), dois modos de aplicação (linha de plantio e área total), duas doses (100 e 200% do N e K necessários à cultura) e um tratamento testemunha (adubação mineral). O lodo de esgoto proporcionou maior acúmulo de N na planta e maior teor residual de N no solo. A aplicação de lodo de esgoto e vinhaça na cultura da cana-de-açúcar pode substituir a adubação mineral, tanto para cana-planta quanto para cana-soca.Sewage sludge is a residue from waste water treatment plants and vinasse is a main effluent from alcohol distilleries. The main differences between them are observed in the nitrogen (N) and potassium (K) contents. Sewage sludge is poor in K, and the vinasse in N. This research was carried out to evaluate sewage sludge and vinasse effects on the nitrogen contents of the plant-soil system and the effects of their application on planted-cane and 1st. ratoon-cane under field conditions, on a Typic Haplustox, in Pontal, State of São Paulo, Brazil, using the sugarcane cultivar SP81-3250. A randomized blocks experimental design was used with 13 treatments and three replications. The results were organized in a 3 × 2 × 2 factorial scheme (three residue forms, two application modes and two rates of N or K) and a control treatment (mineral fertilization). Sewage sludge provided the highest N plant contents and the highest residual N soil contents. Sewage sludge and vinasse can replace mineral fertilization for both planted-cane and 1st. ratoon-cane

Chloride Ingress Resistance, Microstructure and Mechanical Properties of Lightweight Mortars with Natural Cork and Expanded Clay Prepared Using Sustainable Blended Cements

The use of lightweight aggregates in construction materials is a good solution for increasing the contribution to sustainability of civil engineering works, such as maritime ones. In this regard, the possibility of using cork granulates and expanded clay is a current research topic. The combination of eco-friendly cements with lightweight aggregates could provide solutions for developing new building materials. In this work, it has been studied mortars prepared with sustainable cements and the lightweight aggregates of natural cork and expanded clay. These cements incorporated slag, limestone and fly ash. Reference mortars with only sand as aggregate were also made. The total porosity and pore size distributions were obtained. The non-steady-state chloride migration coefficient and compressive and flexural strengths were also determined. The tests were performed at 28 days and 1 year. The differences in the total porosity between the natural cork and expanded clay series were not high, depending on the binder. Natural cork mortars showed similar or slightly higher migration coefficients than the reference and expanded clay mortars at 1 year. This adequate chloride resistance and the low mechanical strengths observed for the natural cork mortars recommend the possible use of this new aggregate in non-structural cement-based materials for civil engineering works exposed to maritime environments.This work was partly funded by FCT/MCTES through national funds (PIDDAC) under the R&D Unit Institute for Sustainability and Innovation in Structural Engineering (ISISE), under reference UIDB/04029/2020, and by the FEDER through the COMPETE2020 program, Portugal 2020, within the scope of project CENTRO-01-0247-FEDER-047067 (LIFE4STONE). José Marcos Ortega is indebted to the Conselleria de Innovación, Universidades, Ciencia y Sociedad Digital de la Generalitat Valenciana (Spain), for a fellowship of the BEST/2020 program (reference BEST/2020/079)

Ant Assemblage Structure in a Secondary Tropical Dry Forest: The Role of Ecological Succession and Seasonality

This study identified the main biological mechanisms governing the diversity of ants on different ecological time scales. Ants were sampled in 15 plots distributed in early, intermediate and late stages of succession (five plots per stage) at the Parque Estadual da Mata Seca, Brazil. At each sample point, unbaited pitfall traps were installed in hypogaeic, epigaeic and arboreal strata. We collected 95 ant species from 26 genera and nine subfamilies. Our results indicated that there was an increase in species richness in advanced stages of succession. We also observed that ant assemblages were different among successional stages. For the arboreal and epigaeic strata, species richness did not change with succession progression, but species composition of these two strata differed among successional stages. Unlike to arboreal and epigaeic ants, hypogaiec ant species richness was higher in the intermediate and late stages of succession and the composition of hypogaeic ants differed among successional stages. Similarity between ant species foraging in arboreal and epigaeic strata decreases with succession progression and β-diversity was higher in advanced successional stages. Additionally, species richness was higher in the dry season, whereas the composition of ant assemblages did not change between seasons. A considerable fraction of the ant assemblage was found only in advanced stages of succession, demonstrating the importance of secondary habitats in maintaining biodiversity in dry forests

hybridModels: An R Package for the Stochastic Simulation of Disease Spreading in Dynamic Networks

Disease spreading simulations are traditionally performed using coupled differential equations. However, in the setting of metapopulations, most of the solutions provided by this method do not account for the dynamic topography of subpopulations. Conversely, the alternative approach of individual-based modeling (IBM) may add computational cost and complexity. Hybrid models allow for the study of disease spreading because they combine both aforementioned approaches by separating them across different scales: a local scale that addresses subpopulation dynamics using coupled differential equations and a global scale that addresses the contact between these subpopulations using IBM. We present a simple way of simulating the spread of disease in dynamic networks using the high-level statistical computational language R and the hybridModels package. We built four examples using disease spread models at the local scale in several different networks: an animal movement network; a three-node network, whose model solution using a stochastic simulation algorithm is compared with the ordinary differential equations approach; the commuting of individuals between patches, which we compare with the permanent migration of individuals; and the commuting of individuals within the metropolitan area of São Paulo

Caracterização e comparação do comportamento espectral de atributos do solo obtidos por sensores orbitais (ASTER e TM) e terrestre (IRIS) Characterization and comparison of soil spectral response obtained from orbital

A utilização, cada vez maior, de informações obtidas por sensoriamento remoto para o estudo de solos torna necessária a avaliação do seu comportamento espectral e de seus atributos. Dessa forma, o presente trabalho objetiva caracterizar o comportamento espectral de atributos do solo a partir de dados obtidos pelo sensor ASTER e compará-lo com o sensor orbital TM-Landsat e terrestre IRIS. Para tanto, foram utilizados dados analíticos de solos da região de Rafard, (SP) e informações obtidas por sensores de satélite e terrestre. As informações foram alocadas sobre a imagem ASTER para a obtenção dos dados de reflectância. Posteriormente, as amostras foram agrupadas em classes para os atributos matéria orgânica, saturação por bases, ferro total e textura para os três sensores utilizados e, as respostas espectrais foram comparadas e caracterizadas. Concluiu-se que o sensor terrestre IRIS é o que melhor discrimina os atributos do solo por ter maior resolução espectral e as bandas dos sensores orbitais ASTER e TM apresentaram correlação negativa para os atributos matéria orgânica, ferro total e argila.AbstractThe increasing use of information obtained from remote sensing for soil science make it necessary the evaluation of soil spectral response and their attributes. The objective of this work was to characterize soil attributes spectral response from data obtained of ASTER sensor and compare with TM – Landsat orbital sensor and IRIS terrestrial sensor. For this, were used analytical data of soil from Rafard, (SP) and information obtained through satellite and terrestrial sensors. After that, the samples points were allocated over ASTER images to obtain de orbital reflectance data. Later, the samples were grouped in classes for organic matter, basis saturation, total iron and texture for all three sensors and the spectral response were compared and characterized. The conclusions are that IRIS terrestrial sensor is the best one for soil attributes discrimination due to its higher spectral resolution and the ASTER and TM orbital sensors bands presented a negative correlation for organic matter, total iron and texture

Geoprocessamento na avaliação espacial de variáveis do solo da região de Rafard-SP

A classificação de um solo é dependente de uma série de fatores químicos, físicos, morfológicos, mineralógicos e topográficos. O entendimento da relação entre estas características auxilia no conhecimento da paisagem e no mapeamento. Desta forma, o objetivo deste trabalho foi verificar a correlação entre classes de solos com informações de geologia, topografia e atributos do solo. Para tanto, foi montado em banco de dados com as informações de análises de solo, curvas de nível e geologia. Estas informações foram cruzadas para verificar a contribuição de cada uma no mapa de solos. Os dados de relevo foram obtidos a partir de um modelo digital do terreno e os de geologia e solo de mapas já existente da área. Concluiu-se que existe alta correlação entre atributos e classes de solo com a geologia da área. Isto sugere que é possível utilizar dados geológicos para delimitação inicial de classes de solos quando a geologia for o fator de formação com maior importância na diferenciação dos solos numa dada região.Soil classification depends on the union of a series of chemical, physical, morphological and topographic factors. The understanding of the relationship among these characteristics aids in the knowledge of the landscape and, consequently, in the mapping. This way, the objective of this work was to verify the spatial correlation among soil classes and information about geology, topography and soils attributes. For this, it was generated a data bank with information about soil analysis, contour lines and geology. This information was crossed to verify the contribution of each one on soil map. The relief data were obtained from digital elevation model and the geology from an existing map of the area. It was concluded that there is high correlation among soil attributes and among them with geology and soil map showing that is possible to use these information to delineate soil classes.Key words:

Vaginal lipidomics of women with vulvovaginal candidiasis and cytolytic vaginosis: a non-targeted LC-MS pilot study

sem informaçãoTo characterize the lipid profile in vaginal discharge of women with vulvovaginal candidiasis, cytolytic vaginosis, or no vaginal infection or dysbiosis. Design. Cross-sectional study. Setting. Genital Infections Ambulatory, Department of Tocogynecology,138sem informaçãosem informaçãosem informaçãoThe supervision of the laboratory studies by Gustavo Henrique Bueno Duarte at Thomson Mass Spectrometry Laboratory–Campinas State Universit

Relação entre pigmentos fotossintéticos e produção de milho sob fontes de nitrogênio

Nitrogen (N) is a dynamic element in the soil, so new nitrogen fertilization alternatives are required as a way of maximizing its efficiency. Besides, vegetation sensors are a way to assess and manage the nutritional demands of plants. This study aimed to evaluate the effect of nitrogen sources on photosynthetic pigments and their correlation with corn grain yield and dry biomass. The experiment was carried out in a randomized block design with nitrogen sources (mineral, organic and biological). Contents of chlorophyll a, b and total, as well as carotenoids, were evaluated. The chlorophyll indices evaluated by both methods were positively correlated with each other and with the grain yield per plant. Nitrogen fertilization 100 % mineral was superior, when compared to the other treatments, with increments of up to 44 %. There was a positive relationship between the methods of determining and estimating the chlorophyll contents. The grain yield per plant showed the highest values when using the 100 % mineral fertilizer source, with increments above 10 %, in relation to the other sources, spending US$89.77 on fertilizer and earning over US$ 538.60 on grain yield. There was a positive correlation between the photosynthetic pigments obtained by both methods and grain yield per plant. Both methods are recommended for the evaluation of chlorophyll concentrations.O nitrogênio (N) é um elemento dinâmico no solo. Dessa forma, novas alternativas de fertilização nitrogenada são demandadas, como forma de maximizar a sua eficiência. Aliado a isso, os sensores de vegetação surgem como forma de avaliar e manejar as demandas nutricionais das plantas. Objetivou-se avaliar o efeito de fontes de nitrogênio nos pigmentos fotossintéticos e sua correlação com o rendimento de grãos e biomassa seca em milho. O experimento foi conduzido em blocos casualizados com fontes de nitrogênio (mineral, orgânica e biológica). Avaliaram-se os teores de clorofila a, b e total, bem como de carotenoides. Os índices de clorofila avaliados por ambos os métodos se correlacionaram positivamente entre si e com o rendimento de grãos por planta. A adubação nitrogenada 100 % mineral foi superior, quando comparada com os demais tratamentos, com incrementos de até 44 %. Verificou-se relação positiva entre os métodos de determinação e a estimativa dos teores de clorofila. O rendimento de grãos por planta apresentou os maiores valores quando se utilizou a fonte de adubação 100 % mineral, apresentando incrementos acima de 10 %, em relação às demais fontes, com gasto de US$89.77 com o fertilizante e ganho acima de US$ 538.60 para o rendimento de grãos. Verificou-se correlação positiva entre os pigmentos fotossintetizantes avaliados por ambos os métodos e o rendimento de grãos por planta. Recomendam-se ambos os métodos para a avaliação das concentrações de clorofila

Reatividade de anticorpos de soros humanos a antígenos de Paracoccidioides brasiliensis tratados com metaperiodato sódico

In this study, we evaluated the profile of anti-Paracoccidioides brasiliensis immunoglobulin isotypes in serum from patients with the acute and chronic forms of paracoccidioidomycosis, using the whole Paracoccidioides brasiliensis antigen and the antigen treated with sodium metaperiodate. All the immunoglobulin isotypes present in the serum from patients with the acute and chronic forms of paracoccidioidomycosis presented higher reactivity towards the whole antigen than to the antigen treated with metaperiodate (P < 0.05). The reactivity of IgG and IgM to the antigen treated with metaperiodate was greater in serum from patients with the acute form of the disease (P < 0.05), while IgA was more reactive in serum from patients with the chronic form (P < 0.05). There was greater reactivity of IgG1 and IgG2 to the whole antigen and the antigen treated with metaperiodate in the serum from patients with paracoccidioidomycosis than there was in serum from patients with other parasitic infections (P < 0.05). Furthermore, IgG1 from patients with the acute form recognized the 19kDa, 27kDa and 31kDa antigens in the western blot test. Thus, the results suggest that modifications to the epitopes of Paracoccidioides brasiliensis antigens may help to improve the immunodiagnosis of paracoccidioidomycosis.Neste trabalho, foi avaliado o perfil de isotipos de imunoglobulinas anti-Paracoccidioides brasiliensis em soros de pacientes com formas crônica e aguda de paracoccidiodomicoses usando antígeno total e tratado com meta-periodato. Todos os tipos de imunoglobulinas presentes nos soros de pacientes com formas aguda e crônica apresentaram alta reatividade ao antígeno total quando comparado ao tratado com meta-periodato (P < 0,05). Houve maior reatividade de IgG e IgM anti-antígeno tratado com meta-periodato em soros de pacientes com forma aguda da doença (P < 0,05), enquanto IgA foi mais reativa em soros da forma crônica (P < 0,05). Houve maior reatividade de IgG1 e IgG2 com antígeno total e tratado com meta-periodato em soros de pacientes comparados aos com outras parasitoses (P < 0,05). Além disso, IgG1 de pacientes com a forma aguda reconhecem antígenos de 19kDa, 27kDa e 31kDa por western blot. Assim, os resultados sugerem que alterações nos epitopos de antígenos de Paracoccidioides brasiliensis podem auxiliar no aprimoramento do imunodiagnóstico da paracoccidioidomicose