5,566 research outputs found

    Estudos de validade da escala de percepções positivas e negativas sobre efeitos do álcool

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    OBJECTIVE To describe the process of elaboration and validation of the Scale of Perceptions about Alcohol Consumption in Higher Education Students in a Portuguese sample, considering the relationship between alcohol use rates and students' perceptions about the effects of this consumption. METHODS The validation study included 531 Portuguese college freshmen who answered the instrument, which is composed of five items that express positive perceptions and five items that express negative perceptions about the effects of alcohol consumption. RESULTS Evidence of content validity, internal structure and external variables were obtained. The results of the factor analysis confirm the distribution of positive and negative perceptions by two different factors according to the theoretical model. Adequate internal consistency indexes were obtained for each dimension. The data obtained showed expected correlations between the perceptions and consumption behaviors of the students, indicating evidence of criterion validity of the scale. Moreover, the study showed that different consumption patterns between men and women, with higher alcohol consumption in the students' households and restaurants or cafés by male students, in addition to the similarity in the consumption pattern between the two genders in parties and bars or nightclubs. CONCLUSION The data obtained show the validity of the instrument. In the discussion, the article presents considerations about the responsibility of higher education institutions in the prevention and reduction in consumption rates among their students.OBJETIVO: Considerando a relação entre as taxas de uso de álcool e as percepções dos estudantes sobre os efeitos desse consumo, descrever o processo de elaboração e validação da Escala de Percepções sobre o Consumo de Álcool em Estudantes do Ensino Superior em uma amostra portuguesa. MÉTODOS: Participaram do estudo de validade 531 estudantes portugueses do primeiro ano do ensino superior que responderam ao instrumento, composto por cinco itens que expressam percepções positivas e cinco itens que expressam percepções negativas sobre os efeitos do consumo de álcool. RESULTADOS: Evidências de validade de conteúdo, de estrutura interna e baseadas em variáveis externas foram obtidas. Os resultados da análise fatorial confirmam a distribuição das percepções positivas e negativas por dois fatores diferenciados em acordo com o modelo teórico de partida. Índices adequados de consistência interna foram obtidos para cada dimensão. Os dados obtidos mostraram correlações esperadas entre as percepções e os comportamentos de consumo dos estudantes, indicando evidências de validade de critério da escala. Em acréscimo, o estudo indicou haver padrões de consumo diferenciados entre os sexos, registando-se maior consumo de álcool nas residências e nos restaurantes ou cafés por parte dos homens, além de similaridade entre os dois sexos no padrão de consumo em festas e bares ou discotecas. CONCLUSÃO: Os dados obtidos evidenciam a validade do instrumento. Na discussão dos dados, o artigo apresenta considerações sobre a responsabilidade das instituições de ensino superior na prevenção e redução das taxas de consumo entre a sua população estudantil. DESCRITORES: Adulto Jovem. Educação Superior. Consumo de Bebidas Alcoólicas, psicologia. Comportamentos de Risco à Saúde. Inquéritos e Questionários. Estudos de Validação.This study is funded by CIEd - Centro de Investigacao em Educacao, project UID/CED/01661/2019, Institute of Education, Universidade de Minho, through national funds of FCT/MCTES-PT. Joana R. Casanova receives funding from the Foundation for Science and Technology, through a doctoral fellowship with the reference SFRH/BD/117902/2016

    End-on PEGylation of heparin: Effect on anticoagulant activity and complexation with protamine

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    Supplementary data to this article can be found online at https://doi.org/10.1016/j.ijbiomac.2023.125957.Heparin is the most common anticoagulant used in clinical practice but shows some downsides such as short half- life (for the high molecular weight heparin) and secondary effects. On the other hand, its low molecular weight analogue cannot be neutralized with protamine, and therefore cannot be used in some treatments. To address these issues, we conjugated polyethylene glycol (PEG) to heparin reducing end (end-on) via oxime ligation and studied the interactions of the conjugate (Hep-b-PEG) with antithrombin III (AT) and protamine. Isothermal titration calorimetry showed that Hep-b-PEG maintains the affinity to AT. Dynamic light scattering demonstrated that the Hep-b-PEG formed colloidal stable nanocomplexes with protamine instead of large multi-molecular aggregates, associated with heparin side effects. The in vitro (human plasma) and in vivo experiments (Sprague Dawley rats) evidenced an extended half-life and higher anticoagulant activity of the conjugate when compared to unmodified heparin.  The authors thank INNO Laboratório Veterinário for the measurements of in vivo coagulation times, Raul Pacheco for discussions about the ITC results, Teresa Oliveira for her help in the in vivo experiments and Ramón Rail for his help in the 3D structures of Fig. 1, Fig. 4. We thank funding provided by the Portuguese Foundation for Science and Technology (PTDC/QUI-POL/28117/2017 and CEECIND/00814/2017). África González-Fernández thanks Xunta de Galicia (Grupo de Referencia competitiva, GRC-ED431C 2020/02) 2020-2023

    IFE Plant Technology Overview and contribution to HiPER proposal

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    HiPER is the European Project for Laser Fusion that has been able to join 26 institutions and signed under formal government agreement by 6 countries inside the ESFRI Program of the European Union (EU). The project is already extended by EU for two years more (until 2013) after its first preparatory phase from 2008. A large work has been developed in different areas to arrive to a design of repetitive operation of Laser Fusion Reactor, and decisions are envisioned in the next phase of Technology Development or Risk Reduction for Engineering or Power Plant facilities (or both). Chamber design has been very much completed for Engineering phase and starting of preliminary options for Reactor Power Plant have been established and review here

    Potassium fertilisation and the thermal behaviour of Cynara cardunculus L.

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    Herbaceous biomass like Cynara is commonly high in potassium, chlorine and ash, which has been reported as a source of problems for combustion applications. An appropriate management of the potassium fertilisation is suggested as a way of improving the quality of the Cynara biomass for solid fuel applications. In this work a factorial experiment was designed involving two types of fertilisers, KCl and K2SO4, and two K rates, in order to study the effect of potassium fertilisation on the composition and thermal behaviour of Cynara biomass. The results proved that the potassium content of Cynara biomass increases with the potassium fertilisation. The thermogravimetric study showed that sintering phenomena can be expected at temperatures higher than 900 °C when the crop has been highly K-fertilised, irrespective of the type of fertiliser used, KCl or K2SO4. However, the SEM images taken of samples of the four K treatments of this experiment did not reveal signs of ash melting, although some particles with crystalline appearance appeared in the samples from highly K-fertilised treatments

    Exploiting the Internet Resources for Autonomous Robots in Agriculture

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    Autonomous robots in the agri-food sector are increasing yearly, promoting the application of precision agriculture techniques. The same applies to online services and techniques implemented over the Internet, such as the Internet of Things (IoT) and cloud computing, which make big data, edge computing, and digital twins technologies possible. Developers of autonomous vehicles understand that autonomous robots for agriculture must take advantage of these techniques on the Internet to strengthen their usability. This integration can be achieved using different strategies, but existing tools can facilitate integration by providing benefits for developers and users. This study presents an architecture to integrate the different components of an autonomous robot that provides access to the cloud, taking advantage of the services provided regarding data storage, scalability, accessibility, data sharing, and data analytics. In addition, the study reveals the advantages of integrating new technologies into autonomous robots that can bring significant benefits to farmers. The architecture is based on the Robot Operating System (ROS), a collection of software applications for communication among subsystems, and FIWARE (Future Internet WARE), a framework of open-source components that accelerates the development of intelligent solutions. To validate and assess the proposed architecture, this study focuses on a specific example of an innovative weeding application with laser technology in agriculture. The robot controller is distributed into the robot hardware, which provides real-time functions, and the cloud, which provides access to online resources. Analyzing the resulting characteristics, such as transfer speed, latency, response and processing time, and response status based on requests, enabled positive assessment of the use of ROS and FIWARE for integrating autonomous robots and the Internet

    Teleseisms monitoring using chirped-pulse φOTDR

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    Monitoring of seismic activity around the word is a topic of high interest for the analysis and understanding of deep Earth dynamics. However, the deployment of a homogeneous network of seismic stations both onshore and offshore poses a strong economic challenge that makes this solution practically inviable. Using the pre-existing fiber optical network for seismic monitoring arises as an excellent solution with important advantages in terms of ubiquity and cost. In this communication, we present the detection of an M8.2 earthquake occurred in Fiji Island using distributed acoustic sensing based on chirped-pulse φOTDR. Two sensors were placed simultaneously at two different locations at >9,000 km from the earthquake epicenter: a metropolitan area and a submarine environment. The recorded data is postprocessed using a 2D linear filter to cancel out environmental noise. The resulting signals are compared with the signals acquired by nearby seismometers. The attained good matching between the recorded data and the seismometer data shows the strong potential of the use of the already-deployed communication fiber network for teleseism monitoring

    Time-expanded FOTDR based on Orthogonal Polarization Frequency Comb generation

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    Phase-sensitive Optical Time-Domain Reflectometry (ΦOTDR) has emerged as an effective and high-performance solution within the realm of Distributed Optical Fiber Sensing (DOFS) technologies, which has promoted its use in an ever-growing number of fields. The challenges arisen by new operation fields demand surpassing the historical trade-offs in this technology, specially aiming for higher resolution without jeopardizing the system simplicity and cost-effectiveness. In this context, time-expanded (TE-)ΦOTDR has been recently proposed as a DOFS solution delivering cm-range resolution with sub-MHz detection and acquisition bandwidths. It is based on the use of an interferometric scheme that employs a dual frequency comb (DFC), consisting of two mutually coherent optical frequency combs with dissimilar repetition rates. In this paper, we present a novel DFC generation scheme for TE-ΦOTDR that exploits the polarization orthogonality. In particular, our approach considerably increases the common path followed by the two frequency combs, thus reducing instability and noise as compared to the conventional generation scheme. Additionally, we employ an IQ modulation scheme with two PRBS generators that increases the scalability of the interrogator while severely reducing its cost and complexity. Results show a reduction in the noise amplitude spectral density especially at low frequency values, which corroborates the stability enhancement of this proposed architecture as compared to the conventional scheme

    Distributed acoustic sensing for seismic activity monitoring

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    Continuous, real-time monitoring of surface seismic activity around the globe is of great interest for acquiring new insight into global tomography analyses and for recognition of seismic patterns leading to potentially hazardous situations. The already-existing telecommunication fiber optic network arises as an ideal solution for this application, owing to its ubiquity and the capacity of optical fibers to perform distributed, highly sensitive monitoring of vibrations at relatively low cost (ultra-high density of point sensors available with minimal deployment of new equipment). This perspective article discusses early approaches on the application of fiber-optic distributed acoustic sensors (DASs) for seismic activity monitoring. The benefits and potential impact of DAS technology in these kinds of applications are here illustrated with new experimental results on teleseism monitoring based on a specific approach: the so-called chirped-pulse DAS. This technology offers promising prospects for the field of seismic tomography due to its appealing properties in terms of simplicity, consistent sensitivity across sensing channels, and robustness. Furthermore, we also report on several signal processing techniques readily applicable to chirped-pulse DAS recordings for extracting relevant seismic information from ambient acoustic noise. The outcome presented here may serve as a foundation for a novel conception for ubiquitous seismic monitoring with minimal investment

    Long-term X-ray changes in the emission from the anomalous X-ray pulsar 4U 0142+61

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    We present results obtained from X-ray observations of the anomalous X-ray pulsar (AXP) 4U 0142+61 taken between 2000-2007 using XMM-Newton, Chandra and Swift. In observations taken before 2006, the pulse profile is observed to become more sinusoidal and the pulsed fraction increased with time. These results confirm those derived using the Rossi X-ray Timing Explorer and expand the observed evolution to energies below 2 keV. The XMM-Newton total flux in the 0.5-10 keV band is observed to be nearly constant in observations taken before 2006, while an increase of ~10% is seen afterwards and coincides with the burst activity detected from the source in 2006-2007. After these bursts, the evolution towards more sinusoidal pulse profiles ceased while the pulsed fraction showed a further increase. No evidence for large-scale, long-term changes in the emission as a result of the bursts is seen. The data also suggest a correlation between the flux and hardness of the spectrum, with brighter observations on average having a harder spectrum. As pointed out by other authors, we find that the standard blackbody plus power-law model does not provide the best spectral fit to the emission from 4U 0142+61. We also report on observations taken with the Gemini telescope after two bursts. These observations show source magnitudes consistent with previous measurements. Our results demonstrate the wide range of X-ray variability characteristics seen in AXPs and we discuss them in light of current emission models for these sources.Comment: 10 pages, 9 figures, in emulateapj style. Submitted to Ap
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