668 research outputs found

    UEFI BIOS Accessibility for the Visually Impaired

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    People with some kind of disability face a high level of difficulty for everyday tasks because, in many cases, accessibility was not considered necessary when the task or process was designed. An example of this scenario is a computer's BIOS configuration screens, which do not consider the specific needs, such as screen readers, of visually impaired people. This paper proposes the idea that it is possible to make the pre-operating system environment accessible to visually impaired people. We report our work-in-progress in creating a screen reader prototype, accessing audio cards compatible with the High Definition Audio specification in systems running UEFI compliant firmware.Comment: 6 page

    Eye evolution simulation with a genetic algorithm based on the hypothesis of Nilsson and Pelger

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    The present work addresses for the first time the simulation of the evolution of an elemental eye by means of a simple genetic algorithm. The problem of the gradual evolution of a structure as complex as the eye was raised by Darwin, being still at the beginning of the 21st century a source of controversy between creationists and evolutionists. Taking as a starting point the paper of Nilsson and Pelger and their hypothesis that the evolution of the eye can be studied if we limit ourselves to its optical geometry, we show how eye evolution could take place gradually applying the principle of natural selection. Our model is limited to studying how an array of photosensitive epithelial cells is bent gradually to achieve a camera obscura

    Fast non-negative deconvolution for spike train inference from population calcium imaging

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    Calcium imaging for observing spiking activity from large populations of neurons are quickly gaining popularity. While the raw data are fluorescence movies, the underlying spike trains are of interest. This work presents a fast non-negative deconvolution filter to infer the approximately most likely spike train for each neuron, given the fluorescence observations. This algorithm outperforms optimal linear deconvolution (Wiener filtering) on both simulated and biological data. The performance gains come from restricting the inferred spike trains to be positive (using an interior-point method), unlike the Wiener filter. The algorithm is fast enough that even when imaging over 100 neurons, inference can be performed on the set of all observed traces faster than real-time. Performing optimal spatial filtering on the images further refines the estimates. Importantly, all the parameters required to perform the inference can be estimated using only the fluorescence data, obviating the need to perform joint electrophysiological and imaging calibration experiments.Comment: 22 pages, 10 figure

    A kinetic model of the central carbon metabolism for acrylic acid production in Escherichia coli

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    Acrylic acid is an economically important chemical compound due to its high market value. Nevertheless, the majority of acrylic acid consumed worldwide its produced from petroleum derivatives by a purely chemical process, which is not only expensive, but it also contributes towards environment deterioration. Hence, justifying the current need for sustainable novel production methods that allow higher profit margins. Ideally, to minimise production cost, the pathway should consist in the direct bio-based production from microbial feedstocks, such as Escherichia coli, but the current yields achieved are still too low to compete with conventional method. In this work, even though the glycerol pathway presented higher yields, we identified the malonyl-CoA route, when using glucose as carbon source, as having the most potential for industrial-scale production, since it is cheaper to implement. Furthermore, we also identified potential optimisation targets for all the tested pathways, that can help the bio-based method to compete with the conventional process.This study was supported by the Portuguese Foundation for Science and Technology(FCT) under the scope of the strategic funding of UIDB/04469/2020 unit. This article is also a result of the project 22231/01/SAICT/2016: “Biodata.pt – Infraestrutura Portuguesa de Dados Biolo´gicos”, by Lisboa Portugal Regional Operational Programme (Lisboa2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). Alexandre Oliveira holds a doctoral fellowship (2020.10205.BD) provided by the FCT. Oscar Dias acknowledge FCT for the Assistant Research contract obtained under CEEC Individual 2018. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.info:eu-repo/semantics/publishedVersio

    The first 62 AGN observed with SDSS-IV MaNGA -- III: stellar and gas kinematics

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    We investigate the effects of Active Galactic Nuclei (AGN) on the gas kinematics of their host galaxies, using MaNGA data for a sample of 62 AGN hosts and 109 control galaxies (inactive galaxies). We compare orientation of the line of nodes (kinematic Position Angle - PA) measured from the gas and stellar velocity fields for the two samples. We found that AGN hosts and control galaxies display similar kinematic PA offsets between gas and stars. However, we note that AGN have larger fractional velocity dispersion σ\sigma differences between gas and stars [σfrac=(σgasσstars)/σstars\sigma_{frac}=(\sigma_{\rm gas}-\sigma_{stars})/\sigma_{\rm stars}] when compared to their controls, as obtained from the velocity dispersion values of the central (nuclear) pixel (2.5" diameter). The AGN have a median value of σfrac\sigma_{\rm frac} of AGN=0.04_{\rm AGN}=0.04, while the the median value for the control galaxies is CTR=0.23_{\rm CTR}=-0.23. 75% of the AGN show σfrac>0.13\sigma_{frac}>-0.13, while 75% of the normal galaxies show σfrac<0.04\sigma_{\rm frac}<-0.04, thus we suggest that the parameter σfrac\sigma_{\rm frac} can be used as an indicative of AGN activity. We find a correlation between the [OIII]λ\lambda5007 luminosity and σfrac\sigma_{frac} for our sample. Our main conclusion is that the AGN already observed with MaNGA are not powerful enough to produce important outflows at galactic scales, but at 1-2 kpc scales, AGN feedback signatures are always present on their host galaxies.Comment: 19 pages, 8 figures, published in MNRA

    A method for the evaluation of the response of torque transducers to dynamic load profiles

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    The traceability of the torque quantity finds a gap when there is a regime with torque variation rates. The traditional calibration methods define the references to be on the static regime, with null torque rates. This paper presents a method for providing torque traceability to rotating sensors under high torque variation rates. The principle of applying acceleration pulses to rotating shafts, with mounted reference discs with known mass moments of inertia thereon, is presented herein, followed by a description of sequential proceedings for obtaining an analysis in the time domain. The development of the uncertainty budget is also discussed. Demonstrative experimental data is used in order to ratify the principle and to maintain a qualitative approach to the theoretical description of these methods. The research gives a very good idea of the necessary different future approaches to guarantee traceability for mechanical quantities

    A method for the evaluation of the response of torque transducers to dynamic load profiles

    Get PDF
    The traceability of the torque quantity finds a gap when there is a regime with torque variation rates. The traditional calibration methods define the references to be on the static regime, with null torque rates. This paper presents a method for providing torque traceability to rotating sensors under high torque variation rates. The principle of applying acceleration pulses to rotating shafts, with mounted reference discs with known mass moments of inertia thereon, is presented herein, followed by a description of sequential proceedings for obtaining an analysis in the time domain. The development of the uncertainty budget is also discussed. Demonstrative experimental data is used in order to ratify the principle and to maintain a qualitative approach to the theoretical description of these methods. The research gives a very good idea of the necessary different future approaches to guarantee traceability for mechanical quantities

    Sows’ parity and coconut oil postnatal supplement on piglets performance

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    ABSTRACTObjectives. The study aimed to evaluate the effect of sows’ of different parities and the supplement of coconut oil for piglets, on the development of litter. Materials and methods. A total of 51 sows of different parities and their 642 piglets were used in the trial. Each piglet was weighed and identified at birth in a sequential order. They were randomly distributed in two treatments (CG=control group and TG=test group). TG piglets had the first access to a dosage of 3.0 ml of coconut oil 12 hours after birth, and the second at 36 h after the first. Piglets were weighed at 21 days. In order to analyze the effect of the coconut oil supplement as a function of the weight at birth, piglets were grouped according to their weight (0.600 to 0.900 kg; 1.000 to 1.499kg; 1.500 to 1.999 kg; and 2.000 to 2.499 kg). Results. Sows parity affected the number and weight of born piglets. Sows in 4th, 5th and 7th parity had a larger litter than those from the 2nd parity. Sows from 2nd and 3rd parity had a lower number of piglets but heavier litter. No effect of the coconut oil supplement on neonatal piglets’ performance was found. Conclusions. The coconut meal was neither beneficial to neonatal piglets nor to those with low weight at birth, which usually present low body energy.RESUMENObjetivo. El objetivo del estudio fue evaluar el efecto del número de partos y el suplemento de aceite de coco en lechones recien nacidos. Materiales y métodos. Se utilizaron 51 cerdas de diferentes partos y sus 642 lechones. Cada lechón se pesó y se identificó al nacer en orden secuencial. Fueron distribuidos aleatoriamente en dos grupos (CG = control y TG=tratamiento). Lechones TG tenían el primer acceso a una dosis de 3.0 ml de aceite de coco 12 horas después del nacimiento, y el segunda a las 36 h después de la primera. Los lechones fueron pesados a los 21 días. Con el fin de analizar el efecto de los suplementos de aceite de coco con relación al peso al nacer. Los lechones fueron agrupados de acuerdo con su peso (0.600 a 0.900 kg; 1.000 a 1.499 kg; 1.500 a 1.999 kg y 2.000 a 2.499 kg). Resultados. El número de partos afectó el peso y el número de lechones nacidos. Cerdas en cuarto, quinto y séptimo parto, tuvieron una camada mayor que las de segundo parto. Las cerdasde segundo y tercer parto tuvieron menor número de lechones y con peso mayor. No se encontró efectodel suplemento de aceite de coco en el desarrollo de los lechones recién nacidos. Conclusiones. Loaceite de coco no es favorable para los lechones recién nacidos, tampoco para aquellos con el bajopeso al nacer, que normalmente presentan la energía corporal baja

    Metallochlorophylls of magnesium, copper and zinc: evaluation of the influence of the first coordination sphere on their solvatochromism and aggregation properties

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    In this study the role of different metal centers (magnesium, zinc and copper) on the enhancement of the hydrophilic character of metallochlorophylls, was evaluated. The solvatochromism as well as the aggregation process for these compounds in water/ethanol mixtures at different volume ratios were evaluated using Fluorescence, and Resonant Light Scattering (RLS) measurements, aiming to characterize the behavior of these compounds. Independently on the studied metallochlorophyll, the presence of at least 60% of water results in a considerable increase in the fluorescence emission, probably a direct consequence of a lower aggregation of these compounds, which is confirmed by the results from RLS measurements. Additionally, the results suggest that magnesium and zinc chlorophyll should be promising phototherapeutic agents for Photodynamic Therapy.No presente estudo, o papel de diferentes centros metálicos (magnésio, zinco e cobre) sobre o caráter hidrofílico de metaloclorofilas foi avaliado. O solvatocromismo, assim como o processo de agregação para esses compostos, em misturas água/etanol foram avaliados usando medidas de fluorescência e de espalhamento de luz ressonante (ELR), visando caracterizar o comportamento desses compostos. Independente da metaloclorofila estudada, a presença de ao menos 60% de água resulta em incremento considerável na emissão de fluorescência apresentada por esses compostos. Isso, provavelmente, é uma conseqüência direta de uma menor agregação, o que é confirmado pelos resultados de ELR. Adicionalmente, os resultados sugerem que as clorofilas de magnésio e de zinco devem ser promissores agentes fototerapêuticos para emprego em Terapia Fotodinâmica.FAPESPFundação AraucáriaFAPEMIGCNPqNanobra
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