2,634 research outputs found

    A datação pelo radiocarbono de elementos de rodas romanas de Madeira para elevação de ågua nas Minas de Rio Tinto

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    Fragmentos de madeira dos raios das rodas utilizadas no sistema de drenagem das minas romanas de Rio Tinto e que se encontram depositados no Museu Mineiro de Rio Tinto foram datados pelo radiocarbono. Todos os fragmentos datados foram identificados como de madeira de sobreiro (Quercus suber) e as datas obtidas foram consideradas como terminii post quem para o fabrico e utilização das referidas rodas. Assim, estas serão atribuíveis aos Sécs. I a III d. C.Wood remains from spokes of Roman water wheels discovered in the Rio Tinto mines (Southern Spain) and currently deposited at the Mines Museum of Rio Tinto were radiocarbon dated. Five samples identified as wood from corkoak (Quercus suber) were processed providing post quem dates for the manufacture and use of the wheels. In this way, these Roman wheels must be ascribed to a period between the first and the third century A.D

    Coronary artery bypass surgery and longitudinal evaluation of the autonomic cardiovascular function

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    INTRODUCTION: Imbalance in autonomic cardiovascular function increases the risk for sudden death in patients with coronary artery disease (CAD), but the time course of the impact of coronary artery bypass grafting (CABG) on autonomic function has been little studied. Thus, the purpose of the present study was to determine the effects of the CABG on the cardiovascular autonomic function. METHODS: Patients undergoing CABG (n = 13) and two matched control groups (patients with CAD who refused surgical treatment [n = 9], and healthy volunteers [n = 9]) underwent a prospective longitudinal study consisting of autonomic evaluation before and after (3, 6, 15, 30, 60, and 90 days) surgery, including measurement of heart rate variability (HRV), respiratory sinus arrhythmia (RSA), and Valsalva maneuver. RESULTS: After CABG there was a decrease in, and a later recovery of, (1) the HRV in the time domain and in the frequency domain, (2) RSA, and (3) Valsalva maneuver. CONCLUSIONS: CABG caused an impairment, reversible after 60 days, of cardiovascular autonomic function, with a maximal decrease on about the sixth day after surgery

    Organic matter sources for tidal marsh sediment over the past two millennia in the Minho River estuary (NW Iberian Peninsula)

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    Environmental changes during the last 2 millennia in the Minho River tidal marsh (NW Portugal-Spain border) were reconstructed. Changes in the sources of organic matter (OM) delivered to the marsh were evaluated from elemental, isotopic and molecular composition using a 1 m sediment core. Carbon isotopic composition (delta13C) and organic carbon to total nitrogen ratio (Corg/N) provided valuable information concerning the origin of the OM. These parameters indicated a major input from land plants, reaching a maximum at 1100–1200 and 1750–1850 AD. These periods match with major flood events in the NW of the Iberian Peninsula, as reported by several authors. A significant reduction in the terrestrial signature occurred at 6–4 cm (ca. 1960–1985 AD), which is contemporaneous with the construction of several major dams on the Minho River. The distribution of selected lipid biomarkers, including n-alkanes, n-fatty acids and n-alkan-2-ones and specific parameters derived from the molecular distributions, were useful for refining bulk geochemical results. Long chain n- alkanes with an odd number of carbons are indicators of soil-and vascular plant derived terrestrial OM and were dominant throughout the core. In addition, a greater contribution of plankton-derived lipids was observed in the sections corresponding to ca. 1960–1985 AD (6–4 cm) and ca. 100–200 AD (96–94 cm). Although different degradation rates for individual compounds might have partly affected biomarker assemblages, the variations could be attributed to a sharp decrease in the freshwater contribution to the Minho River Estuary (dam construction) and a possible marine highstand, respectively. In addition, several parameters suggested changes in land use (including deforestation and farming) and probably the effects of mining exploitation during the Roman occupation of the area.We acknowledge the funding by the Foundation for Science and Technology (FCT) of Portugal for J.M. M’s PhD. Grant (SFRH/BD/45528/2008) and for the WestLog Project (PTDC/CTE-GIX/105370/2008). E.L. was awarded a Ralph E. Powe Junior Faculty Enhancement Award. This is a contribution to the IGCP Project 588 and to the Geo-Q Research Unit (Aranzadi).Peer reviewe

    Thermoelectric properties of n-type poly (ether ether ketone)/carbon nanofiber melt-processed composites

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    The thermoelectric properties, at temperatures from 30 °C to 100 °C, of melt-processed poly(ether ether ketone) (PEEK) composites prepared with 10 wt.% of carbon nanofibers (CNFs) are discussed in this work. At 30 °C, the PEEK/CNF composites show an electrical conductivity (σ) of ~27 S m−1 and a Seebeck coefficient (S) of −3.4 ÎŒV K−1, which means that their majority charge carriers are electrons. The origin of this negative Seebeck is deduced because of the impurities present in the as-received CNFs, which may cause sharply varying and localized states at approximately 0.086 eV above the Fermi energy level (EF) of CNFs. Moreover, the lower S, in absolute value, found in PEEK/CNF composites, when compared with the S of as-received CNFs (−5.3 ÎŒV K−1), is attributed to a slight electron withdrawing from the external layers of CNFs by the PEEK matrix. At temperatures from 30 °C to 100 °C, the σ (T) of PEEK/CNF composites, in contrast to the σ (T) of as-received CNFs, shows a negative temperature effect, understood through the 3D variable-range hopping (VRH) model, as a thermally activated hopping mechanism across a random network of potential wells. Moreover, their nonlinear S (T) follows the same behavior reported before for polypropylene composites melt-processed with similar CNFs at the same interval of temperatures.A. J. Paleo gratefully acknowledges support from FCT-Foundation for Science and Technology by the project UID/CTM/00264/2021 of 2C2T under the COMPETE and FCT/MCTES (PIDDAC) cofinanced by FEDER through the PT2020 program and “plurianual” 2020–2023 Project UIDB/00264/2020. E. Muñoz acknowledges financial support from ANID Anillo ACT/192023 and Fondecyt No 1190361. M. Melle-Franco acknowledges support from the project IF/00894/2015 and within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020, UIDP/50011/2020 & LA/P/0006/2020, financed by national funds through the FCT/MEC (PIDDAC)

    Current control loop design and analysis based on resonant regulators for microgrid applications

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    Voltage and current control loops play an important role in the performance of microgrids employing power electronics voltage source inverters. Correct design of feedback loops is essential for the proper operation of these systems. This paper analyzes the influence of state feedback cross-coupling in the design of resonant regulators for inner current loops in power converters operating in standalone microgrids. It is also demonstrated that the effect of state feedback cross-coupling degrades the performance of the control loops by increasing the steady-state error. Different resonant regulators structures are analyzed and compared, performing experimental tests to validate the results of the theoretical analysis

    Fire behaviour in different periods and configurations of a landscape in Northeastern Portugal

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    Neste trabalho aborda-se a importĂąncia do planejamento do uso e ocupação do solo, e do manejo dos sistemas florestais na redução do perigo de incĂȘndio, analisando-se o comportamento do fogo em relação Ă s alteraçÔes na paisagem da DeilĂŁo, nordeste de Portugal. Foram utilizadas cadeias de Markov e modelos de autĂŽmatos celulares como metodologia para projetar a paisagem no futuro. FlamMap foi utilizado para simular o comportamento do fogo. De acordo com as mĂ©tricas da paisagem obtidas no Fragstats, observou- se que os cenĂĄrios e projeçÔes em DeilĂŁo tĂȘm uma tendĂȘncia Ă  simplificação da paisagem, o que pode facilitar a ocorrĂȘncia de incĂȘndios maiores e mais graves. A anĂĄlise dos resultados indicou uma tendĂȘncia ao aumento do perigo de incĂȘndios na regiĂŁo, em grande parte, ocasionado pela expansĂŁo de plantaçÔes contĂ­nuas de florestas. Para evitar tais impactos, o manejo florestal e ordenamento da paisagem devem ser modificados a fim de se reduzir o acĂșmulo de materiais combustĂ­veis.In this study, we discuss the importance of land use, land cover planning and forest stand management in fire hazard reduction, through the analysis of fire behavior in relation to landscape changes in DeilĂŁo, northeastern Portugal. Markov chains and cellular automata model were used to project future landscapes whose structures were quantified by landscape metrics. The FlamMap model was used to simulate fire behavior. According to landscape metrics from Fragstats, we observed that scenarios and projections in DeilĂŁo have a trend towards landscape simplification, which may facilitate the occurrence of larger, more severe fires. The analyses indicate an increased fire hazard trend in the region, largely caused by the continuity of forest cover. To avoid such impacts, forest management and landscape plannig should be modified in order to reduce the accumulation of combustible materials.info:eu-repo/semantics/publishedVersio

    Use of the Hospital Anxiety and Depression Scale (HADS) in a Cardiac Emergency Room – Chest Pain Unit

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    OBJECTIVE: To determine the prevalence of anxiety and depression in patients complaining of chest pain who seek a chest pain unit attendance. INTRODUCTION: Patients arriving at a Chest Pain Unit may present psychiatric disorders not identified, isolated or co-morbid to the main illness, which may interfere in the patient prognosis. METHODOLOGY: Patients were assessed by the "Hospital Anxiety and Depression Scale" as a screening instrument wile following a systematized protocol to rule out the diagnosis of acute coronary syndrome and other potentially fatal diseases. Patients with 8 or more points in the scale were considered "probable case" of anxiety or depression. RESULTS: According to the protocol, 59 (45.4%) of 130 patients studied presented Chest Pain of Determined Cause, and 71 (54.6%) presented Chest Pain of Indefinite Cause. In the former group, in which 43 (33.1%) had acute coronary syndrome, 33.9% were probable anxiety cases and 30.5% depression cases. In the second group, formed by patients without acute coronary syndrome or any clinical conditions involving greater morbidity and mortality risk, 53.5% were probable anxiety cases and 25.4% depression. CONCLUSION: The high anxiety and depression prevalence observed may indicate the need for early and specialized approach to these disorders. When coronary arterial disease is present, this may decrease complications and shorten hospital stay. When psychiatric disorder appears isolated, is possible to reduce unnecessary repeated visits to emergency room and increase patient's quality of life

    incidence Rate of Psychiatric Disorders in 2020: the Pivotal Role Played By Sars-Cov-2 infection

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    IMPORTANCE: The Coronavirus Disease (COVID-19) pandemic has significantly impacted mental health outcomes. While the frequency of anxiety and depressive symptoms has increased in the whole population, the relationship between COVID-19 and new psychiatric diagnoses remains unclear. OBJECTIVE: to compare the population incidence rate of emergence of de novo psychiatric disorders in 2020 compared to the previous years, and to compare the incidence rate of new psychiatric disorder diagnoses between people with vs without COVID-19. DESIGN, SETTING, AND PARTICIPANTS: This study utilized administrative claims data from the ClinformaticsÂź Data Mart database, licensed from OptumÂź. The study is a cross-sectional analysis that compared the incidence rate of new psychiatric disorders in 2020 vs. 2018 and 2019 in the entire insured population database. Subsequently, the incidence of new psychiatric disorders in people with vs. without COVID-19 during 2020 was analyzed. EXPOSURE: The exposures included diagnosis and severity of COVID-19 infection. MAIN OUTCOMES MEASURES: The dependent variables of interest were the incidence rates of new psychiatric disorders, specifically schizophrenia spectrum disorders, mood disorders, anxiety disorders, and obsessive-compulsive disorder. RESULTS: The population studied included 10,463,672 US adults (mean age 52.83, 52% female) who were unique people for the year of 2020. Incidence of newly diagnosed psychiatric disorders per 1,000 individuals in the 2020 whole population were 28.81 (CI: 28.71, 28.92) for anxiety disorders, 1.04 (CI: 1.02, 1.06) for schizophrenia disorders, 0.42 (CI: 0.41, 0.43) for OCD and 28.85 (CI: 28.75, 28.95) for mood disorders. These rates were not significantly higher than 2018 or 2019. When comparing incidence rates between COVID-19 vs. non-COVID-19 populations in 2020, the rates were significantly higher in the COVID-19 population: 46.89 (CI: 46.24, 47.53) for anxiety, 49.31 (CI: 48.66, 49.97) for mood disorders, 0.57 (CI: 0.50, 0.65) for OCD, and 3.52 (CI: 3.34, 3.70) for schizophrenia. COVID-19 severity was significantly associated with new diagnoses of schizophrenia, anxiety and mood disorders in multivariate analyses. CONCLUSIONS: Compared to 2018 and 2019, in 2020 there was no increased incidence of new psychiatric disorders in the general population based on insurance claims data. Importantly, people with COVID-19 were more likely to be diagnosed with a new psychiatric disorder, most notably disorders with psychosis, indicating a potential association between COVID-19 and mental/brain health

    Green synthesis of polypyrrole-supported metal catalysts: application to nitrate removal in water

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    Pt and Pt/Sn catalysts supported on polypyrrole (PPy) have been prepared using Ar plasma to reduce the metal precursors dispersed on the polymer. The PPy support was synthesized by chemical polymerization of pyrrole with FeCl3·6H2O, this leading to the conducting form of the polymer (conductimetric measurements). The Ar plasma treatment produced a partial reduction of platinum ions, anchored as platinum chloro-complexes to the PPy chain, into metallic platinum. A homogeneous distribution of Pt and Sn nanoparticles was observed by TEM. Activity of the PPy-supported catalysts was evaluated in the reduction of aqueous nitrate with H2 at room temperature. Nitrate concentration in water below the maximum acceptable level of 50 mg L−1 was achieved with all catalysts. However, considering not only efficiency in nitrate reduction, but also minimized concentrations of undesired nitrite and ammonium, the monometallic Pt catalyst seems to be the most promising one.Financial support from Generalitat Valenciana, Spain (PROMETEO/2009/002 – FEDER and PROMETEOII/2014/004) is gratefully acknowledged. Support by PEst-C/EQB/LA0020/2013, financed by FEDER through COMPETE – Programa Operacional Factores de Competitividade, and by FCT – Fundação para a CiĂȘncia e a Tecnologia; NORTE-07-0162-FEDER-000050, financed by QREN, ON2 and FEDER is acknowledged by LCM group. O. S. G. P. Soares acknowledges the grant received from FCT (SFRH/BPD/97689/2013)

    FĂłsseis pleistocĂȘnicos de Scelidodon (Mylodontidae) e Tapirus (Tapiridae) em cavernas paranaenses (PR, sul do Brasil)

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    Notifica-se a primeira ocorrĂȘncia de Scelidodon e Tapirus para a mastofauna pleistocĂȘnica paranaense. O material Ă© procedente de cavernas calcĂĄrias da localidade de Gramados, MunicĂ­pio de Cerro Azul, Estado do ParanĂĄ, Brasil. O gĂȘnero Scelidodon foi reconhecido por um fragmento do dentĂĄrio esquerdo onde estĂĄ inserida a sĂ©rie molariforme completa. O gĂȘnero Tapirus estĂĄ representado por um fragmento do dentĂĄrio direito, no qual estĂĄ implantado o M3. Estas ocorrĂȘncias ampliam a lista de fauna para o Estado do ParanĂĄ, alĂ©m de expandir a distribuição geogrĂĄfica destes gĂȘneros no Brasil. ABSTRACT Two Pleistocene mammals, Scelidodon and Tapirus, are reported at ParanĂĄ State, Southern Brazil for the first time. The specimens were obtained from calcareous caves located at Gramados, Cerro Azul City. The Scelidodon sp. is represented by a fragment of the middle portion of the left dentary with a complete molariform teeth series, and Tapirus sp. is represented by a fragment of the right dentary in which M3 is found inserted. These occurrences enlarge the ParanĂĄ paleomastofauna list and the brazilian geographical distribution of these genera. RÉSUMÉ Ce travail rapport la premiĂšre occurrence, pour letat du ParanĂĄ, sud du BrĂ©sil, de deux mammifĂšres du plĂ©istocĂšne, Scelidodon et Tapirus. Les exemplaires provienent des cavernes calcaires de Gramados, Ă  la ville de Cerro Azul. Le genre Scelidodon est reprĂ©sentĂ© par un fragment du dentaire gauche oĂș est implantĂ© la serie complĂšte des molaires. Le genre Tapirus est reprĂ©sentĂ© par un fragment du dentaire droite oĂș est implantĂ© le M3. Ces occurrences amplifient la liste de la faune de letat du ParanĂĄ, au-delĂ  dĂ©tendre la distribution geographique de ces genres
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