310 research outputs found

    Tuning of fiber optic surface reflectivity through graphene oxide-based Layer-by-Layer film coatings

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    SFRH/BD/135820/2018 UID/EEA/50014/2019 UID/FIS/00068/2019 M-ERA-NET2/0002/2016The use of graphene oxide-based coatings on optical fibers are investigated, aiming to tune the reflectivity of optical fiber surfaces for use in precision sensing devices. Graphene oxide (GO) layers are successfully deposited onto optical fiber ends, either in cleaved or hollow microspheres, by mounting combined bilayers of polyethylenimine (PEI) and GO layers using the Layer-by-Layer (LbL) technique. The reflectivity of optical fibers coated with graphene oxide layers is investigated for the telecom region allowing to both monitor layer growth kinetics and cavity characterization. Tunable reflective surfaces are successfully attained in both cleaved optical fibers and hollow microsphere fiber-based sensors by simply coating them with PEI/GO layers through the LbL film technique.publishersversionpublishe

    Acoustic optical fiber sensor based on graphene oxide membrane

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    A Fabry–Pérot acoustic sensor based on a graphene oxide membrane was developed with the aim to achieve a faster and simpler fabrication procedure when compared to similar graphene-based acoustic sensors. In addition, the proposed sensor was fabricated using methods that reduce chemical hazards and environmental impacts. The developed sensor, with an optical cavity of around 246 µm, showed a constant reflected signal amplitude of 6.8 ± 0.1 dB for 100 nm wavelength range. The sensor attained a wideband operation range between 20 and 100 kHz, with a maximum signal-to-noise ratio (SNR) of 32.7 dB at 25 kHz. The stability and sensitivity to temperatures up to 90◦C was also studied. Moreover, the proposed sensor offers the possibility to be applied as a wideband microphone or to be applied in more complex systems for structural analysis or imaging.publishersversionpublishe

    Fiber Fabry-Perot interferometer for curvature sensing

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    A curvature sensor based on an Fabry-Perot (FP) interferometer was proposed. A capillary silica tube was fusion spliced between two single mode fibers, producing an FP cavity. Two FP sensors with different cavity lengths were developed and subjected to curvature and temperature. The FP sensor with longer cavity showed three distinct operating regions for the curvature measurement. Namely, a linear response was shown for an intermediate curvature radius range, presenting a maximum sensitivity of 68.52 pm/m-1. When subjected to temperature, the sensing head produced a similar response for different curvature radii, with a sensitivity varying from 0.84 pm/°C to 0.89 pm/°C, which resulted in a small cross-sensitivity to temperature when the FP sensor was subjected to curvature. The FP cavity with shorter length presented low sensitivity to curvature

    Dual crop coefficient approach in vitis vinifera L. cv. Loureiro

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    Vineyard irrigation management in temperate zones requires knowledge of the crop water requirements, especially in the context of climate change. The main objective of this work was to estimate the crop evapotranspiration (ETc) of Vitis vinifera cv. Loureiro for local conditions, applying the dual crop coefficient approach. The study was carried out in a vineyard during two growing seasons (2019?2020). Three irrigation treatments, full irrigation (FI), deficit irrigation (DI), and rainfed (R), were considered. The ETc was estimated using the SIMDualKc model, which performs the soil water balance with the dual Kc approach. This balance was performed by calculating the basal coefficients for the grapevine (Kcb crop) and the active soil ground cover (Kcb gcover), which represent the transpiration component of ETc and the soil evaporation coefficient (Ke). The model was calibrated and validated by comparing the simulated soil water content (SWC) with the soil water content data measured with frequency domain reflectometry (FDR). A suitable adjustment between the simulated and observed SWC was obtained for the 2019 R strategy when the model was calibrated. As for the vine crop, the best fit was obtained for Kcb full ini = 0.33, Kcb full mid = 0.684, and Kcb full end = 0.54. In this sense, the irrigation schedule must adjust these coefficients to local conditions to achieve economically and environmentally sustainable production.E518-D54F-9490 | Susana Miguel Afonso Mendes MouraN/

    Hypertension induces additional cardiometabolic impairments and attenuates aerobic exercise training adaptations in fructose-fed ovariectomized rats

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    We tested whether hypertension favors the development of additional cardiometabolic changes in fructose-fed ovariectomized rats and how it affects aerobic exercise training (ET) effects. All rats received fructose in drinking water (10%) beginning at weaning, were ovariectomized at 10 weeks of age and divided into the normotensive sedentary (NFOS) and trained (NFOT) and hypertensive sedentary (HFOS) and trained (HFOT) groups. ET was performed on a treadmill. Arterial pressure (AP) was directly recorded; heart rate and AP variabilities were analyzed. Lipoperoxidation (LPO) and antioxidant enzyme levels were measured in the left ventricle. In addition to increased AP levels, when compared with the NFOS group, the hypertensive groups had resting tachycardia, a reduction of 29% in the pulse interval variance (VAR-PI), 19% in RMSSD (root mean square of successive differences, a cardiac parasympathetic index) and 53% in the α-index (spontaneous baroreflex), while the systolic AP variance (VAR-SAP) and its low-frequency band (LF-SAP) were sharply increased. ET did not alter AP levels. Even in the presence of hypertension, ET induced resting bradycardia, decreases of 33% in VAR-SAP and 49% in LF-SAP, and an increase of more than 60% in VAR-PI and the α-index. However, some of these parameters were still impaired relative to those of normotensive rats. LPO was reduced and catalase was increased in both trained groups, with no difference between the normotensive and hypertensive groups. Negative correlations were obtained between LPO and RMSSD (r=-0.60, P<0.05) and α-index (r=-0.63, P<0.05). In conclusion, hypertension augmented the dysfunctions in fructose-fed ovariectomized rats and attenuated metabolic aerobic ET benefits. These changes may be related to cardiovascular autonomic and oxidative stress alterations.Fil: De Brito Monzani, Janaina O.. Universidade Federal do Maranhao; BrasilFil: Sanches, Iris Callado. Universidade São Judas Tadeu ; BrasilFil: Bernardes, Nathalia. Universidade Nove de Julho; BrasilFil: Ponciano, Kátia. Universidade São Judas Tadeu ; BrasilFil: Moraes Silva, Ivana C.. Universidade de Sao Paulo; BrasilFil: Irigoyen, Maria Cláudia. Universidade de Sao Paulo; BrasilFil: Llesuy, Susana Francisca. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Química Analítica y Fisicoquímica. Cátedra de Química General e Inorgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; ArgentinaFil: De Angelis, Kátia. Universidade Nove de Julho; Brasi

    Outdoor tourism in the North of Portugal from the perspective of tourist entertainment companies (TEC)

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    Based on the perception of those responsible for Tourist Entertainment Companies (TEC), the objective of the research is to contribute to the characterization of Outdoor Tourism (OT). Exploratory qualitative research was carried out through 38 in-depth individual interviews. The territory geography, the experiences, and the internal market were considered relevant aspects. In addition, seasonality and climate were identified as significant factors in defining the offer, which can favour the preservation of the environment. Moreover, the risk of the activities was considered low. The interviewees suggested integrating everyone involved in a network to explore the region's potential, as well as to support activities and promote the region. The radical experience, adventure, and getting out of the routine were identified as motivations for the search, as well as contact with nature and the landscape. The research is limited to the North Region of Portugal, and it brings together the most different needs, desires, and expectations for tourism demand. Strengthening OT can favour employability and, consequently, economic and social balance while promotion of the activity can be explored through the customers' previous experience. The evaluations, testimonials, and word of mouth (WOM) being added value that can be optimized through social networks and digital marketing.This project is being carried out within the scope of the TURNOUT Project-Development of Outdoor Tourism of Northern Portugal, POCI-01-0145-ERDF-032289, financed by the European Investment Fund Regional Development (ERDF) through the Operational Program of Competitiveness and Innovation (POCI) and the Foundation for Science and Technology, IP (OE). UNIAG, R&D unit funded by the FCT-Portuguese Foundation for the Development of Science and Technology, Ministry of Science, Technology and Higher Education. “Project Code Reference: UIDB/04752/2020”. This project also thanks to the reviewers of the ICTR21 conference for their improvement inputs to the paper.info:eu-repo/semantics/publishedVersio

    Monitoring of outdoor tourism demand. North of Portugal

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    The Herfindahl-Hirschman Index (HHI) was used in order to understand the tourism competitiveness of the different sub-regions that make up the North Region of Portugal. This index is a measure which helps to analyse market concentration and at the same time determines the competitiveness of the market.Uniag, IPB, IPP, IPVC, Porto e Norte, FCT, Compete 2020, Portugal 2020, União Europeiainfo:eu-repo/semantics/publishedVersio

    Supply-side perspectives on outdoor tourism in the North of Portugal

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    Nowadays, the tourism sector presents many opportunities and challenges. Outdoor Tourism (OT), due to the unusual situation experienced by the pandemic caused by COVID-19, maybe one of the main opportunities to promote the local development of tourist destinations. Most of the literature developed in this context has focused the demand side. Therefore, the investigation intended to fill this gap, considering the perspective of the supply side, taking into account a vision of sustainable development. To meet this gap, the main objective is to contribute to the characterization of Outdoor Tourism (OT) in the North of Portugal, and understand the potential of OT in the perspective of supply., thirty-eight tourist entertainment companies (TEC) were interviewed to assess supply and perceived customers’ motivations. Of the seven Nomenclature of Territorial Units for Statistical Purposes (NUTS), the Northern region was considered to be an area with enormous potential for Nature-related tourist). For the supply side, seasonality and climate were identified as important factors supporting environment preservation. Radical experiences, adventure and getting out of the routine were identified as motivating demand factors, as well as the contact with Nature and the landscape. We have also observed that if we consider the stimulation of the local economy by OT, there is still a lot to do. The evidence pointed to some social imbalance, namely related to employability. Employees were hired according to the evolution of demand, which favours unemployment and social instability. Also, the tourists/costumers are the main channels of communication of the activities; the word-ofmouth (WOM) of costumers’ experiences, personally or through online social media, takes on a prominent role. In this sense, tourists’ online reviews, testimonies, and word-of-mouth can be optimized through social networks and digital marketing. Finally, to evaluate the region's potential for the OT, the interviewees suggested integrating the players involved with the OT into a single network, supporting the activities and promoting the region.The authors would like to thanks the Project “TURNOUT: Desenvolvimento do Turismo Outdoor da Região Norte de Portugal”, with the reference POCI-01-0145-FEDER-032289, and funded by the European Regional Development Fund (FEDER) (through the Operational Programme ‘Innovation and competitiveness’) and by the Portuguese Foundation for the Development of Science (FCT), of the Ministry of Science, Technology and Higher Education. This work is, also, funded by National Funds through the Foundation for Science and Technology under the project UIDB/04752/2020info:eu-repo/semantics/publishedVersio
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