375 research outputs found

    The Relative Impact of Climate Change on the Extinction Risk of Tree Species in the Montane Tropical Andes.

    Get PDF
    There are widespread concerns that anthropogenic climate change will become a major cause of global biodiversity loss. However, the potential impact of climate change on the extinction risk of species remains poorly understood, particularly in comparison to other current threats. The objective of this research was to examine the relative impact of climate change on extinction risk of upper montane tree species in the tropical Andes, an area of high biodiversity value that is particularly vulnerable to climate change impacts. The extinction risk of 129 tree species endemic to the region was evaluated according to the IUCN Red List criteria, both with and without the potential impacts of climate change. Evaluations were supported by development of species distribution models, using three methods (generalized additive models, recursive partitioning, and support vector machines), all of which produced similarly high AUC values when averaged across all species evaluated (0.82, 0.86, and 0.88, respectively). Inclusion of climate change increased the risk of extinction of 18-20% of the tree species evaluated, depending on the climate scenario. The relative impact of climate change was further illustrated by calculating the Red List Index, an indicator that shows changes in the overall extinction risk of sets of species over time. A 15% decline in the Red List Index was obtained when climate change was included in this evaluation. While these results suggest that climate change represents a significant threat to tree species in the tropical Andes, they contradict previous suggestions that climate change will become the most important cause of biodiversity loss in coming decades. Conservation strategies should therefore focus on addressing the multiple threatening processes currently affecting biodiversity, rather than focusing primarily on potential climate change impacts

    The Orbital Histories of Magellanic Satellites Using Gaia DR2 Proper Motions

    Full text link
    With the release of Gaia DR2, it is now possible to measure the proper motions (PMs) of the lowest mass, ultra-faint satellite galaxies in the Milky Way's (MW) halo for the first time. Many of these faint satellites are posited to have been accreted as satellites of the Magellanic Clouds (MCs). Using their 6-dimensional phase space information, we calculate the orbital histories of 13 ultra-faint satellites and five classical dwarf spheroidals in a combined MW+LMC+SMC potential to determine which galaxies are dynamically associated with the MCs. These 18 galaxies are separated into four classes: i.) long-term Magellanic satellites that have been bound to the MCs for at least the last two consecutive orbits around the MCs (Carina 2, Carina 3, Horologium 1, Hydrus 1); ii.) Magellanic satellites that were recently captured by the MCs << 1 Gyr ago (Reticulum 2, Phoenix 2); iii.) MW satellites that have interacted with the MCs (Sculptor 1, Tucana 3, Segue 1); and iv.) MW satellites (Aquarius 2, Canes Venatici 2, Crater 2, Draco 1, Draco 2, Hydra 2, Carina, Fornax, Ursa Minor). Results are reported for a range of MW and LMC masses. Contrary to previous work, we find no dynamical association between Carina, Fornax, and the MCs. Finally, we determine that the addition of the SMC's gravitational potential affects the longevity of satellites as members of the Magellanic system (long-term versus recently captured), but it does not change the total number of Magellanic satellites.Comment: 32 pages, 11 figures. Accepted to Ap

    Desenvolvimento de ontologias e linguagem de domínio específico para análises de complexidade semântica em nanotecnologia agrícola.

    Get PDF
    A Nanotecnologia consiste no conjunto de técnicas utilizadas para visualização, caracterização, produção e manipulação da matéria na escala de átomos e moléculas (escala nano). As vantagens e aplicações são inúmeras, por isso estratégias de mineração e análises textuais são relevantes para a elaboração de estruturas de genealogia acadêmica para elaboração de grafos que permitam identificar os limites da fronteira do conhecimento e estabelecer métricas para definição de estratégias e políticas de incentivo à pesquisa. Nesse contexto foram empregadas ferramentas de busca acadêmica orientadas a ampliar e analisar um número maior de artigos científicos para permitir a seleção e sistematização das informações técnicas mais relevantes para a Nanotecnologia na Agricultura, para as bases de ontologias agrícolas. Na área de Nanotecnologia foram realizadas buscas em bases científicas internacionais, além de relatório institucionais. Para o desenvolvimento das ontologias foi utilizada a ferramenta Protege utilizando o plugin de OWL e algumas ontologias foram representadas utilizando (CMap). A ontologia final dos descritores da Nanotecnologia para agricultura gerou um mapa conceitual com um framework de organização para os dados de riscos mais relevantes para a liberação e uso da tecnologia. ?- Nanotechnology consists of the set of techniques used for visualization, characterization, production and manipulation of matter at the scale of atoms and molecules (nano scale). The advantages and applications are numerous, so data mining strategies and textual analysis are relevant for the proposition of academic genealogy structures and for the formulation of graphs that allow to identify the limits of the knowledge frontier and to establish metrics for the definition of strategies and policies to encourage search. In this context, academic search tools were used to expand and analyze a larger number of scientific articles to allow the selection and systematization of the most relevant technical information for Nanotechnology in Agriculture, in agricultural ontologies issue. In the area of nanotechnologies it was carried out searches on international scientific bases, as well as institutional reports. For the development of the ontology the Protege tool was used using the OWL plugin and some indicators were showed using the CMap toll. The final ontology of the descriptors of nanotechnology for agriculture generated a conceptual map with an organization framework for the most relevant risk data for the release and use of technology

    A Regional Red List of Montane Tree Species of the Tropical Andes: Trees at the top of the world

    Get PDF
    Andean montane forests are a major global conservation priority owing to their biological richness and high level of species endemism. Botanically the Andes are very rich in species but they remain relatively unstudied. In common with montane forests elsewhere in the world, Andean forests are of great value for the provision of ecosystem services relating to water supply, regulation of regional climate and the capture and storage of carbon. The forests and their component species are however under threat. This report summarises information drawn from a wide variety of sources to provide a regional Red List of trees of Andean tropical montane forests. The species evaluation process has drawn on published national red lists of threatened species, botanical literature, specimen databases, forestry information and expert knowledge. The IUCN Red List Categories and Criteria have been used for the evaluation and a component of Natalia?s PhD study has been to evaluate their use for species with limited and dispersed data. Understanding the geographical distribution of the species is very important in conservation assessment. The maps produced for this study are a valuable starting point for the Red Listing and a baseline for monitoring impacts of climate change. In this assessment 70 species are recorded as globally threatened based on the IUCN Red List of Categories and Criteria out of 127 tree species evaluated. In addition 165 national endemic trees of the region have previously been evaluated as globally threatened based on the same IUCN process. In total therefore 235 tree species are currently considered to be threatened with extinction within the Andean montane forests.Fil: Tejedor Garavito , Natalia. Bournemouth University; Reino UnidoFil: Álvarez Dávila, Esteban. Jardín Botánico de Medellín; ColombiaFil: Caro, Sandra Arango. Missouri Botanical Garden; Estados UnidosFil: Murakami, Alejandro Araujo. Museo de Historia Natural Noel Kempff Mercado; BoliviaFil: Baldeón, Severo. Universidad Nacional Mayor de San Marcos; PerúFil: Beltrán, Hamilton. Universidad Nacional Mayor de San Marcos; PerúFil: Blundo, Cecilia Mabel. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Laboratorio de Investigaciones Ecológicas de las Yungas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; ArgentinaFil: Boza Espinoza, Tatiana Erika. Missouri Botanical Garden; Estados UnidosFil: Fuentes Claros, Alfredo. Herbario Nacional de Bolivia; BoliviaFil: Gaviria, Juan. Universidad de Los Andes; VenezuelaFil: Gutiérrez, Néstor. Universidad de Los Andes; VenezuelaFil: Khela, Sonia. Botanic Gardens Conservation International; Reino UnidoFil: León, Blanca. University of Texas at Austin; Estados UnidosFil: la Torre Cuadros, Maria De Los Angeles. Universidad Nacional Agraria; PerúFil: López Camacho, René. Universidad Distrital; ColombiaFil: Malizia, Lucio Ricardo. Universidad Nacional de Jujuy. Facultad de Ciencias Agrarias. Centro de Estudios Ambientales Territoriales y Sociales; ArgentinaFil: Millán, Betty. Universidad Nacional Mayor de San Marcos; PerúFil: Moraes R., Mónica. Herbario Nacional de Bolivia; BoliviaFil: Newton, Adrian C.. Bournemouth University; Reino UnidoFil: Pacheco, Silvia. Fundación Proyungas; ArgentinaFil: Reynel, Carlos. Universidad Nacional Agraria; PerúFil: Ulloa Ulloa, Carmen. Missouri Botanical Garden; Estados UnidosFil: Vacas Cruz,Omar. Pontificia Universidad Católica del Ecuador; Ecuado

    Global estimates of pregnancies at risk of Plasmodium falciparum and Plasmodium vivax infection in 2020 and changes in risk patterns since 2000.

    Get PDF
    BACKGROUND: Women are at risk of severe adverse pregnancy outcomes attributable to Plasmodium spp. infection in malaria-endemic areas. Malaria control efforts since 2000 have aimed to reduce this burden of disease. METHODS: We used data from the Malaria Atlas Project and WorldPop to calculate global pregnancies at-risk of Plasmodium spp. infection. We categorised pregnancies as occurring in areas of stable and unstable P. falciparum and P. vivax transmission. We further stratified stable endemicity as hypo-endemic, meso-endemic, hyper-endemic, or holo-endemic, and estimated pregnancies at risk in 2000, 2005, 2010, 2015, 2017, and 2020. FINDINGS: In 2020, globally 120.4M pregnancies were at risk of P. falciparum, two-thirds (81.0M, 67.3%) were in areas of stable transmission; 85 2M pregnancies were at risk of P. vivax, 93.9% (80.0M) were in areas of stable transmission. An estimated 64.6M pregnancies were in areas with both P. falciparum and P. vivax transmission. The number of pregnancies at risk of each of P. falciparum and P. vivax worldwide decreased between 2000 and 2020, with the exception of sub-Saharan Africa, where the total number of pregnancies at risk of P. falciparum increased from 37 3M in 2000 to 52 4M in 2020. INTERPRETATION: Historic investments in malaria control have reduced the number of women at risk of malaria in pregnancy in all endemic regions except sub-Saharan Africa. Population growth in Africa has outpaced reductions in malaria prevalence. Interventions that reduce the risk of malaria in pregnancy are needed as much today as ever
    corecore