447 research outputs found

    Seismo-electromagnetic phenomena in the western part of the Eurasia-Nubia plate boundary

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    This paper presents a future research plan that aims to monitor Seismo-electromagnetic (SEM) phenomena in the western part of the Eurasia-Nubia plate boundary (WENP). This region has a significant tectonic activity [1] combined with relatively low electromagnetic noise levels and for that reason presents the possibility to perform high quality SEM measurements. Further, it is known that low-frequency [ultra (ULF), very (VLF), and low-frequencies (LF)] electromag- netic (EM) waves produce more convincing earthquake precursors (compared to higher frequencies) because of less contamination, large skin depth, and low attenuation [2]. Thus, two SEM effects will be considered: ULF electromagnetic field emissions [3], and VLF/LF radio broadcastings [4]. With respect to the ULF measurements, as a start, three ULF sensors are planned to be installed in the South of Iberian Peninsula supported by the existing networks of seismic research stations. Subsequent devel- opment of this initial plan could result in the implementation of a lager ULF monitoring network not only in the Iberian Peninsula, but also in the rest of Europe. Possible integration in the SEGMA array is now under consideration. Another perspective is to use a portable station to track seismic events. Regarding the VLF/LF radio broadcastings, a receiver is planned to be mounted in University of Évora. Radio signals from up to 10 transmitters (in these bands) of interest to study the seismic activity in the WENP region will be monitored. Actually, the radio path from the transmitter to the receiver should cross the epicentral area, therefore two possible transmitters are the ones installed in Monaco (France) and Sicily (Italy). Furthermore, the system will integrate the INFREP network and in this context it will not be restricted to WENP region. With the development of these research plans we aim to collect novel SEM data emerging from the seis- mic activity in the WENP region. We expect to address the time variations of EM properties of the crust/plate in relation with the strain field, and in space in relation with composition and temperature and stress fields. Further, the interplay between atmospheric (and solar) perturbations with crust perturbations will be monitored, to observe geomagnetic perturbations at different locations. Our study will be focused in the analyses of low magnitude earthquakes with M =< 4, these events are frequent in the WENP region, but have been almost completely disregarded in literature [5,6]. [1] J. Borges, A. J. S. Fitas, M. Bezzeghoud, and P. Teves-Costa, Tectonophysics 337, 373 (2001). [2] V. Chauhan, O.P. Singh, V. Kushwah, V. Singh, B. Singh, Journal of Geodynamics 48, 68 (2009). [3] L. Telesca, V. Lapenna, M. Macchiato, and K. Hattori, Earth and Planet. Science Lett. 268, 219 (2008)

    Seismo-electromagnetic phenomena in the western part of the Eurasia-Nubia plate boundary

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    This paper presents a future research plan that aims to monitor Seismo-electromagnetic (SEM) phenomena in the western part of the Eurasia-Nubia plate boundary (WENP). This region has a significant tectonic activity [1] combined with relatively low electromagnetic noise levels and for that reason presents the possibility to perform high quality SEM measurements. Further, it is known that low-frequency [ultra (ULF), very (VLF), and low-frequencies (LF)] electromag- netic (EM) waves produce more convincing earthquake precursors (compared to higher frequencies) because of less contamination, large skin depth, and low attenuation [2]. Thus, two SEM effects will be considered: ULF electromagnetic field emissions [3], and VLF/LF radio broadcastings [4]. With respect to the ULF measurements, as a start, three ULF sensors are planned to be installed in the South of Iberian Peninsula supported by the existing networks of seismic research stations. Subsequent devel- opment of this initial plan could result in the implementation of a lager ULF monitoring network not only in the Iberian Peninsula, but also in the rest of Europe. Possible integration in the SEGMA array is now under consideration. Another perspective is to use a portable station to track seismic events. Regarding the VLF/LF radio broadcastings, a receiver is planned to be mounted in University of Évora. Radio signals from up to 10 transmitters (in these bands) of interest to study the seismic activity in the WENP region will be monitored. Actually, the radio path from the transmitter to the receiver should cross the epicentral area, therefore two possible transmitters are the ones installed in Monaco (France) and Sicily (Italy). Furthermore, the system will integrate the INFREP network and in this context it will not be restricted to WENP region. With the development of these research plans we aim to collect novel SEM data emerging from the seis- mic activity in the WENP region. We expect to address the time variations of EM properties of the crust/plate in relation with the strain field, and in space in relation with composition and temperature and stress fields. Further, the interplay between atmospheric (and solar) perturbations with crust perturbations will be monitored, to observe geomagnetic perturbations at different locations. Our study will be focused in the analyses of low magnitude earthquakes with M =< 4, these events are frequent in the WENP region, but have been almost completely disregarded in literature [5,6]. [1] J. Borges, A. J. S. Fitas, M. Bezzeghoud, and P. Teves-Costa, Tectonophysics 337, 373 (2001). [2] V. Chauhan, O.P. Singh, V. Kushwah, V. Singh, B. Singh, Journal of Geodynamics 48, 68 (2009). [3] L. Telesca, V. Lapenna, M. Macchiato, and K. Hattori, Earth and Planet. Science Lett. 268, 219 (2008)

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    Bryophyte diversity and climate change in the Azores: looking to the future to redesign the present

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    Jornadas "Ciência nos Açores – que futuro? Tema Ciências Naturais e Ambiente", Ponta Delgada, 7-8 de Junho de 2013.As alterações que o clima do planeta tem vindo a sofrer nas últimas décadas têm efeitos variados sobre a biodiversidade, alterando a distribuição das espécies e as interacções entre estas, afectando a jusante os serviços de ecossistemas e, consequentemente, o ser humano. Nos Açores, vários desses serviços são garantidos pelos briófitos. Para além das suas funções ecossistémicas, estes organismos respondem rapidamente a variações ambientais, sendo por isso indicados para detectar os efeitos biológicos das alterações climáticas. Este estudo procura determinar que impactos terão as alterações climáticas previstas pelo Intergovernmental Panel on Climate Change sobre a distribuição e composição específica e funcional da brioflora dos Açores e que novos dados podemos integrar no sistema de gestão de áreas protegidas do arquipélago. Para tal, pretende-se inventariar a diversidade específica e funcional de briófitos ao longo de gradientes altitudinais em várias ilhas dos Açores, relacionar os padrões de distribuição encontrados com uma série de factores ambientais e desenvolver, através de modelação bioclimática, previsões da distribuição futura destas espécies em resposta a diferentes cenários de alterações climáticas. Utilizando a brioflora açoriana, pretende-se assim ilustrar de que forma o estudo dos futuros efeitos das alterações climáticas sobre a biodiversidade pode servir como base para o desenvolvimento de estratégias de gestão e conservação da natureza a curto, médio e longo prazos. Ao fazê-lo, estaremos a contribuir para garantir a sustentabilidade do arquipélago, preservando a sua biodiversidade, os serviços dos ecossistemas e os benefícios e lucros por eles gerados em sectores como o do turismo, fortemente ligado à qualidade ambiental das ilhas.ABSTRACT: The changes the planet's climate has undergone in recent decades have numerous effects on biodiversity, altering the distribution of species and the interactions between them, affecting the ecosystem services they provide and, consequently, human beings. In the Azores, many of these services are guaranteed by bryophytes. Besides, these organisms respond quickly to environmental changes, being thus very suitable for exploring the biological effects of climate change. This project aims to determine what will the impacts of climate change, as predicted by the Intergovernmental Panel on Climate Change, on the distribution, taxonomic and functional composition of native forest bryophytes be and which new data can we integrate in the archipelago’s protected areas management system. In order to do that, we will sample the taxonomic and functional diversity of bryophytes along altitudinal gradients in several islands of the Azores in a stratified way, and relate the emerging distribution patterns with a number of environmental factors. Then, using bioclimatic modeling, we will predict the future distribution of these species in response to different climate change scenarios. By means of the Azorean bryophytes, we aim to illustrate how the study of future climate change effects on biodiversity can serve as a foundation for the development of short to long-term nature management and conservation strategies. In doing so, we will help to ensure the sustainability of the archipelago, preserving its biodiversity, ecosystem services and the benefits and profits generated by them in sectors such as tourism, strongly linked to the environmental quality of the islands.Governo dos Açores; Fundo Regional para a Ciência

    Long-term monitoring across elevational gradients to assess ecological hypothesis : a description of standardized sampling methods in oceanic islands and first results

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    We are launching a long-term study to characterize the biodiversity at different elevations in several Azorean Islands. Our aim is to use the Azores as a model archipelago to answer the fundamental question of what generates and maintains the global spatial heterogeneity of diversity in islands and to be able to understand the dynamics of change across time. An extensive, standardized sampling protocol was applied in most of the remnant forest fragments of five Azorean Islands. Fieldwork followed BRYOLAT methodology for the collection of bryophytes, ferns and other vascular plant species. A modified version of the BALA protocol was used for arthropods. A total of 70 plots (10 m x 10 m) are already established in five islands (Flores, Pico, São Jorge, Terceira and São Miguel), all respecting an elevation step of 200 m, resulting in 24 stations examined in Pico, 12 in Terceira, 10 in Flores, 12 in São Miguel and 12 in São Jorge. The first results regarding the vascular plants inventory include 138 vascular species including taxa from Lycopodiophyta (N=2), Pteridophyta (N=27), Pinophyta (N=2) and Magnoliophyta (N=107). In this contribution we also present the main research question for the next six years within the 2020 Horizon

    The MOVECLIM – AZORES project: Bryophytes from Pico Island (2012)

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    ABSTRACT: In September 2012, Pico Island was surveyed along an elevational transept starting on Manhenha, at 10 m a.s.l., and ending on the Pico Mountain caldera, at 2200 m a.s.l. to obtain a systematic inventory of the bryophytes living in natural environments. A total of twelve sites were examined, separated by 200 m elevation steps. At each site, two 10 m x 10 m plots were established within 10-15 m from each other, and within each plot, three 2 m x 2 m quadrats were randomly selected and thoroughly sampled for bryophytes using microplots of 10 cm x 5 cm, collected to paper bags. Six substrates were explored within each quadrat: rock, soil, humus, organic matter, tree bark and leaves/fronds; three replicates were made for each substrate, whenever available and colonized by bryophytes, totalling a maximum of 18 microplots per quadrat, 54 microplots per plot, 108 microplots per site and 1296 microplots on the 12 sites of Pico Island. It was possible to collect two thirds of the maximum expected number of microplots (N=878; 67,75%), resulting in 4896 specimens, the great majority of which (n=4869) were identified to the species/subspecies level. Overall, it was possible to identify 70 moss’ and 71 liverwort’ species and subspecies. The elevation levels both with a greater number of microplots and higher richness of species were those between 600-1000 m a.s.l., coinciding with the native forest plots. The study contributed to improve the knowledge of Azorean bryophyte diversity and distribution at both local and regional scales, including the recording of new taxa for Pico Island and the Azores.info:eu-repo/semantics/publishedVersio

    Interleukin 6 Is a Stronger Predictor of Clinical Events Than High-Sensitivity C-Reactive Protein or D-Dimer During HIV Infection

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    BACKGROUND: Interleukin 6 (IL-6), high-sensitivity C-reactive protein (hsCRP), and D-dimer levels are linked to adverse outcomes in human immunodeficiency virus (HIV) infection, but the strength of their associations with different clinical end points warrants investigation. METHODS: Participants receiving standard of care in 2 HIV trials with measured biomarker levels were followed to ascertain all-cause death, non–AIDS-related death, AIDS, cardiovascular disease (CVD), and non–AIDS-defining malignancies. Hazard ratios (HRs) and 95% confidence intervals (CIs) of each end point for quartiles and log2-transformed IL-6, hsCRP, and D-dimer levels were calculated using Cox models. Marginal models modelling multiple events tested for equal effects of biomarker levels on different end points. RESULTS: Among 4304 participants, there were 157 all-cause deaths, 117 non–AIDS-related deaths, 101 AIDS cases, 121 CVD cases, and 99 non–AIDS-defining malignancies. IL-6 was more strongly associated with most end points, compared with hsCRP. IL-6 appeared to be a stronger predictor than D-dimer for CVD and non–AIDS-defining malignancies, but 95% CIs overlapped. Independent associations of IL-6 were stronger for non–AIDS-related death (HR, 1.71; 95% CI, 1.43–2.04) and all-cause death (HR, 1.56; 95% CI, 1.33–1.84) and similar for CVD (HR, 1.35; 95% CI, 1.12–1.62) and non–AIDS-defining malignancies (HR, 1.30; 95% CI, 1.06–1.61). There was heterogeneity of IL-6 (P < .001) but not hsCRP (P = .15) or D-dimer (P = .20) as a predictor for different end points. CONCLUSIONS: IL-6 is a stronger predictor of fatal events than of CVD and non–AIDS-defining malignancies. Adjuvant antiinflammatory and antithrombotic therapies should be tested in HIV-infected individuals

    Antiproliferative effects of Tubi-bee propolis in glioblastoma cell lines

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    Propolis is a resin formed by a complex chemical composition of substances that bees collect from plants. Since ancient times, propolis has been used in folk medicine, due to its biological properties, that include antimicrobial, anti-inflammatory, antitumoral and immunomodulatory activities. Glioblastoma is the most common human brain tumor. Despite the improvements in GBM standard treatment, patients’ prognosis is still very poor. The aim of this work was to evaluate in vitro the Tubi-bee propolis effects on human glioblastoma (U251 and U343) and fibroblast (MRC-5) cell lines. Proliferation, clonogenic capacity and apoptosis were analyzed after treatment with 1 mg/mL and 2 mg/mL propolis concentrations for different time periods. Additionally, glioblastoma cell lines were submitted to treatment with propolis combined with temozolomide (TMZ). Data showed an antiproliferative effect of tubi-bee propolis against glioblastoma and fibroblast cell lines. Combination of propolis with TMZ had a synergic anti-proliferative effect. Moreover, propolis caused decrease in colony formation in glioblastoma cell lines. Propolis treatment had no effects on apoptosis, demonstrating a cytostatic action. Further investigations are needed to elucidate the molecular mechanism of the antitumor effect of propolis, and the study of its individual components may reveal specific molecules with antiproliferative capacity
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