Análise de curto-circuito em sistemas desequilibrados de distribuição com geração distribuída

No presente trabalho, realiza-se uma análise numérica de faltas em sistemas de distribuição desequilibrados com geração distribuída. Na metodologia proposta, o cálculo das correntes de curto-circuito utiliza uma versão trifásica da matriz impedância de barra em componentes de fase. Na obtenção dessa matriz, é utilizado o método de construção direta, implementado no ambiente computacional MATLAB®. Para avaliar os resultados da metodologia, o sistema teste IEEE 13 barras modificado foi modelado e simulado, sendo realizada a análise de curto-circuito considerando o aumento gradual do nível de penetração da geração distribuída, permitindo assim analisar o impacto dos geradores no nível de curto-circuito do sistema elétrico.In the present work, a numerical analysis of faults in unbalanced distribution systems with distributed generation is carried out. In the proposed methodology, the calculation of short-circuit currents uses a three-phase version of the bus-impedance matrix in phase components. In order to obtain this matrix, the direct construction method was implemented in the MATLAB® computational environment. In order to evaluate the results of the methodology, the modified IEEE 13 nodes test feeder was modeled and simulated, considering the gradual increase of distributed generation penetration, thus allowing to analyze the impact of distributed generation on the short-circuit level of the electric system

Through the Eyes of a Bee: Seeing the World as a Whole

Honeybees are an important model species for understanding animal vision as free-flying individuals can be easily trained by researchers to collect nutrition from novel visual stimuli and thus learn visual tasks. A leading question in animal vision is whether it is possible to perceive all information within a scene, or if only elemental cues are perceived driven by the visual system and supporting neural mechanisms. In human vision we often process the global content of a scene, and prefer such information to local elemental features. Here we discuss recent evidence from studies on honeybees which demonstrate a preference for global information. We explore insights from imaging studies suggesting why a global preference may be important for foraging in natural environments where a holistic representation of elemental factors is advantageous. Thus we aim to provide a brief new insight into how animal vision may perceive the complex world in which we must all operate and suggest further ways to test this

Changing How Biologists View Flowers-Color as a Perception Not a Trait

Studying flower color evolution can be challenging as it may require several different areas of expertise, ranging from botany and ecology through to understanding color sensing of insects and thus how they perceive flower signals. Whilst studies often view plant-pollinator interactions from the plant's perspective, there is growing evidence from psychophysics studies that pollinators have their own complex decision making processes depending on their perception of color, viewing conditions and individual experience. Mimicry of rewarding flowers by orchids is a fascinating system for studying the pollinator decision making process, as rewarding model flowering plants and mimics can be clearly characterized. Here, we focus on a system where the rewardless orchid Eulophia zeyheriana mimics the floral color of Wahlenbergia cuspidata (Campanulaceae) to attract its pollinator species, a halictid bee. Using recently developed psychophysics principles, we explore whether the color perception of an insect observer encountering variable model and mimic flower color signals can help explain why species with non-rewarding flowers can exist in nature. Our approach involves the use of color discrimination functions rather than relying on discrimination thresholds, and the use of statistical distributions to model intraspecific color variations. Results show that whilst an experienced insect observer can frequently make accurate discriminations between mimic and rewarding flowers, intraspecific signal variability leads to overlap in the perceived color, which will frequently confuse an inexperienced pollinator. This new perspective provides an improved way to incorporate pollinator decision making into the complex field of plant-pollinator interactions.AD was supported by the Australian Research Council Discovery Projects grant DP160100161

Molecular studies on genetic variability and plant-pathogens interactions in pearl millet downy mildew (Sclerospora graminicola) pathogen

This file contains all choices for each bee during the 50 conditioned choices of the learning phase for both Group 1 and Group 2

Fragmentary Blue: Resolving the Rarity Paradox in Flower Colors

Blue is a favored color of many humans. While blue skies and oceans are a common visual experience, this color is less frequently observed in flowers. We first review how blue has been important in human culture, and thus how our perception of blue has likely influenced the way of scientifically evaluating signals produced in nature, including approaches as disparate as Goethe’s Farbenlehre, Linneaus’ plant taxonomy, and current studies of plant-pollinator networks. We discuss the fact that most animals, however, have different vision to humans; for example, bee pollinators have trichromatic vision based on UV-, Blue-, and Green-sensitive photoreceptors with innate preferences for predominantly short-wavelength reflecting colors, including what we perceive as blue. The subsequent evolution of blue flowers may be driven by increased competition for pollinators, both because of a harsher environment (as at high altitude) or from high diversity and density of flowering plants (as in nutrient-rich meadows). The adaptive value of blue flowers should also be reinforced by nutrient richness or other factors, abiotic and biotic, that may reduce extra costs of blue-pigments synthesis. We thus provide new perspectives emphasizing that, while humans view blue as a less frequently evolved color in nature, to understand signaling, it is essential to employ models of biologically relevant observers. By doing so, we conclude that short wavelength reflecting blue flowers are indeed frequent in nature when considering the color vision and preferences of bees.publishedVersio

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

AI is a viable alternative to high throughput screening: a 318-target study

: High throughput screening (HTS) is routinely used to identify bioactive small molecules. This requires physical compounds, which limits coverage of accessible chemical space. Computational approaches combined with vast on-demand chemical libraries can access far greater chemical space, provided that the predictive accuracy is sufficient to identify useful molecules. Through the largest and most diverse virtual HTS campaign reported to date, comprising 318 individual projects, we demonstrate that our AtomNet® convolutional neural network successfully finds novel hits across every major therapeutic area and protein class. We address historical limitations of computational screening by demonstrating success for target proteins without known binders, high-quality X-ray crystal structures, or manual cherry-picking of compounds. We show that the molecules selected by the AtomNet® model are novel drug-like scaffolds rather than minor modifications to known bioactive compounds. Our empirical results suggest that computational methods can substantially replace HTS as the first step of small-molecule drug discovery

Differentiating biological colours with few and many sensors: Spectral reconstruction with RGB and hyperspectral cameras

This Dataverse holds supporting data for the paper "Differentiating biological colour with few and many sensors: Spectral reconstruction with RGB and hyperspectral cameras" by Garcia, Girard, Kasumovic, Petersen, Wilksch and Dyer 2015. The data consists on: a) non-linear RGB TIFF images; b) linearised version of images in a) stored as 3888 x 2592 x 3 matlab matrices where monochrome images corresponding to the red, green and blue colour channels are stored along the thrid dimension of the matrix, following Matlab's standard format for RGB images; c) A Matlab files directory containing a matrix (.mat) file storing linear RGB values for the calibration set and reflectance spectra readings corresponding to each sample in the set. This data is required for the spectral reconstruction of any given RGB combination. Code for performing the spectral reconstruction mentioned in the paper is also provided as a plain, txt file. Copy and paste the contents of this file into a matlab function page for creating the function in your own machine. d) An excel file containing the data in c) for reference purposes. The authors provide the code without any warranty. Please refer to the publication for more details