1,702 research outputs found

    A ubiquitous learning approach on robotics

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    Ubiquitous learning refers to the integration of learning processes with everyday environments and activities using technology. By leveraging ubiquitous learning principles in the field of robotics, we can foster an immersive and interactive learning environment that promotes continuous learning and knowledge acquisition. This paper presents an in-depth exploration of a ubiquitous learning approach for robotics with the aim to enhance the educational experiences and capabilities of robotic systems. Furthermore, it explores the potential benefits and challenges of ubiquitous learning in the field of robotics, such as increased adaptability, personalized learning experiences, and the development of lifelong learning skills. The results indicate that a ubiquitous learning approach can significantly enhance the learning capabilities of students.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) for financial support through national funds FCT/MCTES (PIDDAC) to CeDRI (UIDB/05757/2020 and UIDP/05757/2020) and SusTEC (LA/P/0007/2021).info:eu-repo/semantics/publishedVersio

    On the width of the last scattering surface

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    We discuss the physical effects of some accelerated world models on the width of the last scattering surface (LSS) of the cosmic microwave background radiation (CMBR). The models considered in our analysis are X-matter (XCDM) and a Chaplygin type gas. The redshift of the LSS does not depend on the kind of dark energy (if XCDM of Chaplygin). Further, for a Chaplygin gas, the width of the LSS is also only weakly dependent on the kind of scenario (if we have dark energy plus cold dark matter or the unified picture).Comment: 10 pages, 1 figure, 2 tables, accepted to IJMP

    Legume and Nitrogen Fertilization Affect Animal Performance and Enteric Methane Emission of Nellore Heifers

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    Methane emission from livestock operation is an important source of greenhouse gas and contributes to global warming. Forage legume secondary compounds may mitigate methane emissions by reducing methanogenic population in the rumen. This study evaluated animal performance and methane emission from beef cattle grazing either a mixed pasture [Brachiaria brizantha cv. Marandu (palisadegrass) and Arachis pintoi (forage peanut) cv. BRS Mandobi] or a palisadegrass monoculture with or without nitrogen (N) fertilisation. A 2.5-yr continuous stocking experiment was carried out in southeast Brazil, on a randomized complete block design with three treatments and four replicates. Two Nellore heifers were used as tester animals and additional put-and-takes were used to keep canopy height at 20-25 cm. The treatments comprised three pasture types: 1) palisadegrass-forage peanut mixed pasture (GRASS+LEGUME); 2) palisadegrass + 150 kg N/ha/year (GRASS+N); 3) palisadegrass without N fertilization (GRASS). Response variables included average daily gain (ADG), forage intake, and methane emission. Methane emission was estimated by the sulphur hexafluoride (SF6) tracer technique. There was no difference between grazing systems for the ADG (P = 0.439) and DMI (P = 0.394; averages of 0.433 kg/d and 2.10 %BW/d, respectively). In the GRASS+LEGUME, there was a decrease of 11.7% in methane emission per animal (148 vs. 170 and 165 g/day for GRASS+N and GRASS, respectively; P = 0.001). Grazing systems including legume reduced methane emission per unit of ADG (365 vs. 428 and 398 g/kg for GRASS and GRASS+N, respectively; P = 0.061) and per carcass gain (656 vs. 800 g of methane/kg carcass for GRASS; P = 0.022). Intake of condensed tannins was greater for GRASS+LEGUME (0.61 vs. 0.17 %BW/d, P \u3c 0.001). Forage peanut decreased enteric methane emission intensity, reducing carbon footprint of livestock systems in Southeast Brazil

    How Does N Fertilization or Forage Legumes Affect Forage and Animal Production?

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    Livestock grazing in tropical climates is characterized by low productivity. Forage and animal production can be improved by applying nitrogen (N) fertiliser or using forage legumes. This 2.5-yr study assessed the canopy structure and productivity of beef cattle grazing either a mixed pasture of Brachiaria brizantha cv. Marandu (palisadegrass) and Arachis pintoi (forage peanut) cv. BRS Mandobi or a Marandu palisade grass monoculture with or without N fertilisation. The experiment was carried out in Southeast Brazil, where the canopy structure (herbage mass) and animal productivity (stocking rate and liveweight gain per ha) were compared for three types of pastures: 1) mixed pasture of Marandu palisade grass and forage peanut (GRASS+LEGUME); 2) a monoculture of Marandu palisadegrass fertilised with 150 kg N/ha/year (GRASS+N); and 3) monoculture of Marandu palisadegrass without N application (GRASS), under continuous stocking. A minimum of two Nellore heifers and additional put-and-takes were used to keep canopy height at 20-25 cm. A randomized complete block design was used with four replicates; seasons were considered repeated measurements over time. Herbage mass was greater in the GRASS+N pasture (P \u3c 0.001); however, in the last three seasons (Spring II, Summer III, and Fall III), there was no difference to GRASS+LEGUME pasture. In the GRASS+LEGUME pasture, there was an increase of legume mass (1.260 to 2.565 kg/ha) and botanical composition (23.6 to 39.1% of legume in forage mass) throughout the study. The stocking rate (P \u3c 0.001) and liveweight gain per ha (P \u3c 0.001) were greater in GRASS+N, without difference among GRASS+LEGUME and GRASS pastures in the first seven seasons. In the last three seasons, with an increase of legume proportion, stocking rate and liveweight were intermediate for GRASS+LEGUME pasture. Legume increased herbage mass and animal productivity in the long term. Immediate responses were achieved with N fertilization

    Mobile laboratories as an alternative to conventional remote laboratories

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    Remote laboratories have been playing an important role on the improvement of flexibility and the extent of practical activities in teaching and learning activities in engineering and technology. However, the current remote laboratories model does not consider dynamic scenarios including collaboration, peer-to-peer labs and mobile labs. This paper presents a set of tools for creating collaborative online mobile laboratories that allow students to develop their own labs and share them with classmates and teachers. The approach used is compatible with the machine and network configurations that the target user has in schools and at home, and provides the retrieval of information for learning evaluation.info:eu-repo/semantics/publishedVersio

    Smart systems for monitoring buildings - an IoT application

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    Life in society has initiated a search for comfort and security in social centers. This search generated revolutions within the knowledge about the technologies involved, making the environments automated and integrated. Along with this increase, ecological concerns have also arisen, which have been involved since the design of intelligent buildings, remaining through the years of their use. Based on these two pillars, the present study aims to monitor three central systems inside the apartments of the Apolo Building (Bragan¸cacity, Portugal). The electrical energy consumption, water flow, and waste disposal systems are integrated through a single database. The data is sent remotely via WiFi through the microcontroller. For better visualization and analytics of the data, a web application is also developed, which allows for real-time monitoring. The obtained results demonstrate to the consumer his behavior regarding household expenses. The idea of showing the consumer their expenditure is to create an ecological awareness. Through the data collected and the environmental alternatives found, it is possible to observe whether there was a behavior change when receiving this data, either in the short or long term.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) for financial support through national funds FCT/MCTES (PIDDAC) to CeDRI (UIDB/05757/2020 and UIDP/05757/2020) and SusTEC (LA/P/0007/2021). Thadeu Brito was supported by FCT PhD grant SFRH/BD/08598 /2020 and João Braun received the support of a fellowship from ”la Caixa” Foundation (ID 100010434) with code LCF/BQ/DI20/11780028.info:eu-repo/semantics/acceptedVersio

    Life table analysis of Diaphorina citri (Hemiptera: Psyllidae) infesting sweet orange (Citrus sinensis) in São Paulo

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    An ecological life table for eggs and nymphs of Diaphorina citri Kuwayama (Hemiptera: Psyllidae) was constructed with data obtained from orange orchards (Citrus sinensis Osbeck) in 2 regions of the State of São Paulo, over 4 generations in the period from XI-2006 to V-2007, comprising spring, summer, and fall seasons. Young growing shoots with D. citri eggs present were identifed, and live individuals were counted until adult emergence. No predatory arthropods were observed in association with D. citri eggs and nymphs during the study. The mean parasitism of fourth- and ffth-instar nymphs by Tamarixia radiata Waterston (Hymenoptera: Eulophidae) was 2.3%. The durations of the egg–adult period were similar among the 4 generations, ranging from 18.0 to 24.7 d (at mean temperatures ranging from 21.6 to 26.0 °C) and followed the temperature requirement models obtained in the laboratory for D. citri. However, survival from the egg to the adult stage for the same period varied considerably from 1.7 to 21.4%; the highest mortalities were observed in the egg and small nymphal (frst- to thirdinstar) stages, which were considered to be key phases for population growth of the pest.Uma tabela de vida ecológica foi construída para ovos e ninfas de Diaphorina citri Kuwayama (Hemiptera: Psyllidae) com dados obtidos em pomares de laranja (Citrus sinensis Osbeck) em 2 regiões do estado de São Paulo, com 4 gerações, no período de novembro de 2006 a maio de 2007, compreendendo as estações de primavera, verão e outono. Ramos jovens em crescimento com a presença de ovos de D. citri foram identificados e os indivíduos vivos foram contados até a emergência dos adultos. Nenhum predador foi observado associado a ovos e ninfas de D. citri durante o estudo. A taxa média de parasitismo de ninfas de quarto e quinto ínstares por Tamarixia radiata Waterson (Hymenoptera: Eulophidae) foi de 2.3%. A duração do período de ovo a adulto foi semelhante entre as quatro gerações, variando de 18.0 a 24.7 dias (com temperaturas médias de 21.6 a 26.0 °C) e seguiram os modelos de exigencias térmicas obtidas em laboratório para D. citri. Todavia, a sobrevivencia de ovo até o estágio adulto variou consideravelmente para o mesmo período, de 1.7 a 21.4%, sendo que as maiores mortalidades foram observadas nos estágios de ovos e ninfas pequenas (de primeiro a terceiro ínstares), as quais foram consideradas fases chaves para o crescimento populacional desta praga.info:eu-repo/semantics/publishedVersio

    Effects of insemination and blood-feeding on locomotor activity of Aedes albopictus and Aedes aegypti (Diptera: Culicidae) females under laboratory conditions

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    Background\ud Dengue is an arbovirus disease transmitted by two Aedes mosquitoes: Ae. aegypti and Ae. albopictus. Virgin females of these two species generally show a bimodal and diurnal pattern of activity, with early morning and late afternoon peaks. Although some studies on the flight activity of virgin, inseminated and blood-fed Ae. aegypti females have been carried out under laboratory conditions, little is known about the effects of such physiological states on the locomotor activity of Ae. albopictus and Ae. aegypti females. The aim of this study was to analyze, under laboratory conditions, the effects of insemination and blood-feeding on the locomotor activity of Ae. albopictus and Ae. aegypti females under LD 12:12, at 25°C.\ud \ud \ud Methods\ud Both Ae. albopictus and Ae. aegypti females were obtained from established laboratory colonies. Control groups were represented by virgin/unfed Ae. albopictus and Ae. aegypti females. Experiments were conducted under laboratory conditions, using an activity monitor that registers individual activity every thirty minutes.\ud \ud \ud Results\ud Virgin/unfed Ae. albopictus and Ae. aegypti females showed a diurnal and bimodal pattern of locomotor activity, with peaks at early morning and late afternoon. Insemination and blood-feeding significantly decreased the locomotor activity of Ae. aegypti females, but inseminated/blood-fed Ae. aegypti and Ae. albopictus females showed a similar significant decrease on the locomotor activity compared to virgin/unfed females.\ud \ud \ud Conclusions\ud This study is the first demonstration of the effects of insemination and blood-feeding on the locomotor activity of Ae. albopictus and Ae. aegypti females under artificial conditions. Data suggest that Ae. albopictus and Ae. aegypti females respond in different ways to physiological status changes and such divergence between these two dengue vectors, associated with several ecological differences, could be related to the greater dengue vectorial capacity of Ae. aegypti in Americas in comparison to Ae. albopictus.HHMIFiocruzFaperjCNP

    Impact of organizational factors on accident prediction in the retail sector

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    Although different actions to prevent accidents at work have been implemented in companies, the number of accidents at work continues to be a problem for companies and society. In this way, companies have explored alternative solutions that have improved other business factors, such as predictive analysis, an approach that is relatively new when applied to occupational safety. Nevertheless, most reviewed studies focus on the accident dataset, i.e., the casualty’s characteristics, the accidents’ details, and the resulting consequences. This study aims to predict the occurrence of accidents in the following month through different classification algorithms of Machine Learning, namely, Decision Tree, Random Forest, Gradient Boost Model, K-nearest Neighbor, and Naive Bayes, using only organizational information, such as demographic data, absenteeism rates, action plans, and preventive safety actions. Several forecasting models were developed to achieve the best performance and accuracy of the models, based on algorithms with and without the original datasets, balanced for the minority class and balanced considering the majority class. It was concluded that only with some organizational information about the company can it predict the occurrence of accidents in the month ahead.USDA - U.S. Department of Agriculture(PCIF/GRF/0141/2019)The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) for financial support through national funds FCT/MCTES (PIDDAC) to CeDRI (UIDB/05757/2020 and UIDP/05757/2020), ALGORITMI UIDB/00319/2020 and SusTEC (LA/P/0007/2021). This work has been supported by NORTE-01-0247-FEDER-072598 iSafety: Intelligent system for occupational safety and well-being in the retail sector. Inˆes Sena was supported by FCT PhD grant UI/BD/153348/2022
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