189 research outputs found

    Development of a selective and sensitive sensor for urate determination based on tris(1,10-phenantroline)copper(II) bis(tetracyanoquinodimethanide) adsorbed on carbon nanotubes

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    The present work describes the development of a selective electrochemical sensor for urate based on tris(1,10-phenantroline) copper(II) bis(tetracyanoquinodimethanide) (Cu(phen)(3)(TCNQ)(2)) adsorbed on multi-walled carbon nanotubes (CNT). The composite material was characterized by infrared spectroscopy, scanning electron microscopy, and electrochemical impedance spectroscopy. The composite material showed an excellent electrocatalytic activity toward oxidation of urate. The heterogeneous charge transfer rate constant (k') between the analyte and the sensor was determined using linear sweep voltammetry experiments. The composite material shows a linear range from 5 up to 2500 mu mol L-1 with limit of detection of 1.05 mu mol L-1 and limit of quantification of 3.50 mu mol L-1. The high sensitivity and selectivity of the sensor for urate was sufficient for its determinationThe present work describes the development of a selective electrochemical sensor for urate based on tris(1,10-phenantroline)copper(II) bis(tetracyanoquinodimethanide) (Cu(phen)3(TCNQ)2) adsorbed on multi-walled carbon nanotubes (CNT). The composite materi261020352045FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPEMA - FUNDAÇÃO DE AMPARO A PESQUISA E AO DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO DO MARANHÃOsem informaçãosem informaçãosem informaçãoThe authors are grateful to Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), INCTBio, Rede Mineira de Química, and Fundação de Amparo à Pesquisa do Estado do Maranhão (FAPEMA

    a cross-cultural comparison between Portugal and the United States

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    Background: Motor competence and health-related fitness are important components for the development and maintenance of a healthy lifestyle in children. This study examined cross-cultural performances on motor competence and health-related fitness between Portuguese and U.S. children. Methods: Portuguese (n = 508; 10.14 +/- 2.13 years , mean +/- SD) and U.S. (n = 710; 9.48 +/- 1.62 years) children performed tests of cardiorespiratory fitness (Progressive Aerobic Cardiovascular Endurance Run), upper body strength (handgrip), locomotor skill performance (standing long jump), and object projection skill performance (throwing and kicking). Portuguese and U.S. children were divided into 2 age groups (6=9 and 10=13 years) for data analysis purposes. A two=factor one=way analysis of covariance (ANOVA) was conducted with the Progressive Aerobic Cardiovascular Endur ance Run, handgrip, standing long jump scores, kicking, and throwing speed (km/h) as dependent variables. Results: Results indicated that Portuguese children, irrespective of sex, presented better performances in locomotor and cardiorespiratory performance (standing long jump and Progressive Aerobic Cardiovascular Endurance Run) than U.S. children in both age bands. U.S. children outper formed Portuguese children during throwing and handgrip tests. Kicking tests presented gender differences: Portuguese boys and U.S. girls outperformed their internationally matched counterparts. Conclusion: Cultural differences in physical education curricula and sports participation may impact differences in motor competence and fitness development in these countries.4811-99FE-2ECD | Luis Paulo RodriguesN/

    MAMMALS IN PORTUGAL : A data set of terrestrial, volant, and marine mammal occurrences in P ortugal

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    Mammals are threatened worldwide, with 26% of all species being includedin the IUCN threatened categories. This overall pattern is primarily associatedwith habitat loss or degradation, and human persecution for terrestrial mam-mals, and pollution, open net fishing, climate change, and prey depletion formarine mammals. Mammals play a key role in maintaining ecosystems func-tionality and resilience, and therefore information on their distribution is cru-cial to delineate and support conservation actions. MAMMALS INPORTUGAL is a publicly available data set compiling unpublishedgeoreferenced occurrence records of 92 terrestrial, volant, and marine mam-mals in mainland Portugal and archipelagos of the Azores and Madeira thatincludes 105,026 data entries between 1873 and 2021 (72% of the data occur-ring in 2000 and 2021). The methods used to collect the data were: live obser-vations/captures (43%), sign surveys (35%), camera trapping (16%),bioacoustics surveys (4%) and radiotracking, and inquiries that represent lessthan 1% of the records. The data set includes 13 types of records: (1) burrowsjsoil moundsjtunnel, (2) capture, (3) colony, (4) dead animaljhairjskullsjjaws, (5) genetic confirmation, (6) inquiries, (7) observation of live animal (8),observation in shelters, (9) photo trappingjvideo, (10) predators dietjpelletsjpine cones/nuts, (11) scatjtrackjditch, (12) telemetry and (13) vocalizationjecholocation. The spatial uncertainty of most records ranges between 0 and100 m (76%). Rodentia (n=31,573) has the highest number of records followedby Chiroptera (n=18,857), Carnivora (n=18,594), Lagomorpha (n=17,496),Cetartiodactyla (n=11,568) and Eulipotyphla (n=7008). The data setincludes records of species classified by the IUCN as threatened(e.g.,Oryctolagus cuniculus[n=12,159],Monachus monachus[n=1,512],andLynx pardinus[n=197]). We believe that this data set may stimulate thepublication of other European countries data sets that would certainly contrib-ute to ecology and conservation-related research, and therefore assisting onthe development of more accurate and tailored conservation managementstrategies for each species. There are no copyright restrictions; please cite thisdata paper when the data are used in publications.info:eu-repo/semantics/publishedVersio

    A search for ultra-high-energy photons at the Pierre Auger Observatory exploiting air-shower universality

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    The Pierre Auger Observatory is the most sensitive detector to primary photons with energies above ∼0.2 EeV. It measures extensive air showers using a hybrid technique that combines a fluorescence detector (FD) with a ground array of particle detectors (SD). The signatures of a photon-induced air shower are a larger atmospheric depth at the shower maximum (Xmax_{max}) and a steeper lateral distribution function, along with a lower number of muons with respect to the bulk of hadron-induced background. Using observables measured by the FD and SD, three photon searches in different energy bands are performed. In particular, between threshold energies of 1-10 EeV, a new analysis technique has been developed by combining the FD-based measurement of Xmax_{max} with the SD signal through a parameter related to its muon content, derived from the universality of the air showers. This technique has led to a better photon/hadron separation and, consequently, to a higher search sensitivity, resulting in a tighter upper limit than before. The outcome of this new analysis is presented here, along with previous results in the energy ranges below 1 EeV and above 10 EeV. From the data collected by the Pierre Auger Observatory in about 15 years of operation, the most stringent constraints on the fraction of photons in the cosmic flux are set over almost three decades in energy

    Study on multi-ELVES in the Pierre Auger Observatory

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    Since 2013, the four sites of the Fluorescence Detector (FD) of the Pierre Auger Observatory record ELVES with a dedicated trigger. These UV light emissions are correlated to distant lightning strikes. The length of recorded traces has been increased from 100 μs (2013), to 300 μs (2014-16), to 900 μs (2017-present), to progressively extend the observation of the light emission towards the vertical of the causative lightning and beyond. A large fraction of the observed events shows double ELVES within the time window, and, in some cases, even more complex structures are observed. The nature of the multi-ELVES is not completely understood but may be related to the different types of lightning in which they are originated. For example, it is known that Narrow Bipolar Events can produce double ELVES, and Energetic In-cloud Pulses, occurring between the main negative and upper positive charge layer of clouds, can induce double and even quadruple ELVES in the ionosphere. This report shows the seasonal and daily dependence of the time gap, amplitude ratio, and correlation between the pulse widths of the peaks in a sample of 1000+ multi-ELVES events recorded during the period 2014-20. The events have been compared with data from other satellite and ground-based sensing devices to study the correlation of their properties with lightning observables such as altitude and polarity

    Outreach activities at the Pierre Auger Observatory

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    The ultra-high-energy cosmic-ray sky above 32 EeV viewed from the Pierre Auger Observatory

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    First results from the AugerPrime Radio Detector

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    Update of the Offline Framework for AugerPrime

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