2,428 research outputs found

    Oil Extraction and Indigenous Livelihoods in the Northern Ecuadorian Amazon

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    Globally, the extraction of minerals and fossil fuels is increasingly penetrating into isolated regions inhabited by indigenous peoples, potentially undermining their livelihoods and well-being. To provide new insight to this issue, we draw on a unique longitudinal dataset collected in the Ecuadorian Amazon over an 11-year period from 484 indigenous households with varying degrees of exposure to oil extraction. Fixed and random effects regression models of the consequences of oil activities for livelihood outcomes reveal mixed and multidimensional effects. These results challenge common assumptions about these processes and are only partly consistent with hypotheses drawn from the Dutch disease literature

    Portable X‐ray fluorescence spectroscopy as a tool for cyclostratigraphy

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    Cyclostratigraphic studies are used to create relative and high‐resolution timescales for sedimentary successions based on identification of regular cycles in climate proxy data. This method typically requires the construction of long high‐resolution datasets. In this study, we have demonstrated the efficacy of portable X‐ray fluorescence spectroscopy (pXRF) as a non‐destructive method of generating compositional data for cyclostratigraphy. The rapidity (100 samples per day) and low cost of pXRF measurements provide advantages over relatively time‐consuming and costly elemental and stable isotopic measurements that are commonly used for cyclostratigraphy. The non‐destructive nature of pXRF also allows other geochemical analyses on the same samples. We present an optimized protocol for pXRF elemental concentration measurement in powdered rocks. The efficacy of this protocol for cyclostratigraphy is demonstrated through analysis of 360 Toarcian mudrock samples from North Yorkshire, UK, that were previously shown to exhibit astronomical forcing of [CaCO3], [S] and δ13Corg. Our study is the first to statistically compare the cyclostratigraphic results of pXRF analysis with more established combustion analysis. There are strong linear correlations of pXRF [Ca] with dry combustion elemental analyzer [CaCO3] (r2=0.7616), and pXRF [S] and [Fe] with dry combustion elemental analyzer [S] (r2=0.9632 and r2=0.9274 respectively). Spectral and cross‐spectral analysis demonstrates that cyclicity previously recognized in [S], significant above the 99.99% confidence level, is present above the 99.92% and 99.99% confidence levels in pXRF [S] and [Fe] data respectively. Cyclicity present in [CaCO3] data above the 99.96% confidence level is also present in pXRF [Ca] above the 98.12% confidence level

    A Dust Twin of Cas A: Cool Dust and 21-micron Silicate Dust Feature in the Supernova Remnant G54.1+0.3

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    We present infrared (IR) and submillimeter observations of the Crab-like supernova remnant (SNR) G54.1+0.3 including 350 micron (SHARC-II), 870 micron (LABOCA), 70, 100, 160, 250, 350, 500 micron (Herschel) and 3-40 micron (Spitzer). We detect dust features at 9, 11 and 21 micron and a long wavelength continuum dust component. The 21 micron dust coincides with [Ar II] ejecta emission, and the feature is remarkably similar to that in Cas A. The IRAC 8 micron image including Ar ejecta is distributed in a shell-like morphology which is coincident with dust features, suggesting that dust has formed in the ejecta. We create a cold dust map that shows excess emission in the northwestern shell. We fit the spectral energy distribution of the SNR using the continuous distributions of ellipsoidal (CDE) grain model of pre-solar grain SiO2 that reproduces the 21 and 9 micron dust features and discuss grains of SiC and PAH that may be responsible for the 10-13 micron dust features. To reproduce the long-wavelength continuum, we explore models consisting of different grains including Mg2SiO4, MgSiO3, Al2O3, FeS, carbon, and Fe3O4. We tested a model with a temperature-dependent silicate absorption coefficient. We detect cold dust (27-44 K) in the remnant, making this the fourth such SNR with freshly-formed dust. The total dust mass in the SNR ranges from 0.08-0.9 Msun depending on the grain composition, which is comparable to predicted masses from theoretical models. Our estimated dust masses are consistent with the idea that SNe are a significant source of dust in the early Universe.Comment: MNRAS: accepted on June 28, 2018 and published on July 4, 201

    Predictive Monitoring for Respiratory Decompensation Leading to Urgent Unplanned Intubation in the Neonatal Intensive Care Unit

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    Background: Infants admitted to the neonatal intensive care unit (NICU), and especially those born with very low birth weight (VLBW; \u3c 1,500 g), are at risk for respiratory decompensation requiring endotracheal intubation and mechanical ventilation. I ntubation and mechanical ventilation are associated with increased morbidity, particularly in urgent unplanned cases. Methods: We tested the hypothesis that the systemic response associated with respiratory decombensation can be detected from physiological monitoring and that statistical models of bedside monitoring data can identify infants at increased risk of urgent unplanned intubation. We studied 287 VLBW infants consecutively admitted to our NICU and found 96 events in 51 patients, excluding intUbations occurring within. 12h of a previous extubation. Results: In order of importance in a multivariable statistical model, we found that the characteristics of reduced O-2 satura, tion, especially as heart rate was falling; increased heart rate correlation with respiratory rate; and the amount of apnea were aIF significant independent pr,edictors.\u27 The predictive model, validated internally by bootStrap, had a receiver-operating characteristic area of 0.84 + / - 0.04. Conclusion: We propose that predictive monitoring in the NICU for urgent unplanned intubation may improve outcomes by allowing clinicians to intervene noninvasively before intubation is required

    Asymmetric forest transition driven by the interaction of socioeconomic development and environmental heterogeneity in Central America

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    Forest transitions (FT) have been observed in many developed countries and more recently in the developing world. However, our knowledge of FT from tropical regions is mostly derived from case studies from within a particular country, making it difficult to generalize findings across larger regions. Here we overcome these difficulties by conducting a recent (2001-2010) satellite-based analysis of trends in forest cover across Central America, stratified by biomes, which we related to socioeconomic variables associated with human development. Results show a net decrease of woody vegetation resulting from 12,201 km2 of deforestation of moist forests and 6,825 km2 of regrowth of conifer and dry forests. The Human Development Index was the socioeconomic variable best associated with forest cover change. The least-developed countries, Nicaragua and Guatemala, experienced both rapid deforestation of moist forests and significant recovery of conifer and dry forests. In contrast, the most developed countries, Panama and Costa Rica, had net woody vegetation gain and amore stable forest cover configuration. These results imply a good agreement with FT predictions of forest change in relation to socioeconomic development, but strong asymmetry in rates and directions of change largely dependent upon the biomewhere change is occurring. The FT model should be refined by incorporating ecological and socioeconomic heterogeneity, particularly inmulticountry and regional studies. These asymmetric patterns of forest change should be evaluatedwhen developing strategies for conserving biodiversity and environmental services.Fil: Redo, Daniel J.. Universidad de Puerto Rico; Puerto RicoFil: Grau, Hector Ricardo. Universidad Nacional de Tucumán; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Aide, T. Mitchell. Universidad de Puerto Rico; Puerto RicoFil: Clark, Matthew L.. Sonoma State University; Estados Unido

    Land Change in the Greater Antilles between 2001 and 2010

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    Land change in the Greater Antilles differs markedly among countries because of varying socioeconomic histories and global influences. We assessed land change between 2001 and 2010 in municipalities (second administrative units) of Cuba, Dominican Republic, Haiti, Jamaica, and Puerto Rico. Our analysis used annual land-use/land-cover maps derived from MODIS satellite imagery to model linear change in woody vegetation, mixed-woody/plantations and agriculture/herbaceous vegetation. Using this approach, we focused on municipalities with significant change (p ≤ 0.05). Between 2001 and 2010, the Greater Antilles gained 801 km2 of woody vegetation. This increase was mainly due to the return of woody vegetation in Cuba, and smaller increases in Puerto Rico and the Dominican Republic. Despite relatively similar environments, the factors associated with these changes varied greatly between countries. In Puerto Rico, Dominican Republic, and Jamaica, agriculture declined while mixed-woody vegetation increased, mostly in montane regions. In contrast, Cuba experienced an extensive decline in sugarcane plantations, which resulted in the spread of an invasive woody shrub species and the increase in woody vegetation in areas of high agricultural value. In Haiti, the growing population, fuelwood consumption, and increase in agriculture contributed to woody vegetation loss; however, woody vegetation loss was accompanied with a significant increase in the mixed woody and plantations class. Most regional analyses often treated the Greater Antilles as a homogeneous unit; our results suggest that historical and socio-economic differences among countries are crucial for understanding the variation in present day land change dynamics.Fil: Alvarez Berrios, Nora L.. Universidad de Puerto Rico; Puerto RicoFil: Redo, Daniel J.. Universidad de Puerto Rico; Puerto RicoFil: Aide, T. Mitchell. Universidad de Puerto Rico; Puerto RicoFil: Clark, Matthew L.. Sonoma State University; Estados UnidosFil: Grau, Hector Ricardo. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Ecología Regional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

    Strontium and Oxygen Isotope Profiles of Sequentially Sampled Modern Bison (Bison bison bison) Teeth from Interior Alaska as Proxies of Seasonal Mobility

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    Studies addressing prehistoric mobility in animals typically use isotopic analyses of sequentially formed tissues, such as the growth layers in teeth, to infer physical movement on the landscape. Strontium isotope ratios (87Sr/86Sr values), which vary geographically, are particularly useful for this purpose, especially when paired with stable oxygen isotope ratios (δ18O), which vary seasonally. Together, these two isotope systems can provide information about past animal movement patterns on a seasonal scale. However, while many studies have used 87Sr/86Sr and δ18O values from analyses of sequentially formed tissues for this purpose, there have been limited analyses on modern animals of known movement patterns across high-latitude regions. In this pilot study, we sequentially sampled and analyzed one second molar (M2) and two third molars (M3) from two bison (Bison bison bison) from the Delta bison herd, which resides in interior Alaska and has known and documented seasonal mobility patterns. The resulting 87Sr/86Sr values from the teeth were compared to a high-resolution 87Sr/86Sr isoscape for the region and were paired with δ18O analyses to determine whether the seasonal 87Sr/86Sr values matched the predicted values for each of the seasonal bison habitat areas. The results indicate that the 87Sr/86Sr and δ18O values reliably reflected the known seasonal mobility patterns of bison and suggest that this approach could be used to investigate the mobility patterns of prehistoric bison in Alaska and surrounding high-latitude regions.En général, les études qui portent sur la mobilité des animaux préhistoriques se servent d’analyses isotopiques des tissus séquentiellement formés, y compris les couches de développement des dents, afin d’en déduire les mouvements physiques dans l’environnement. Les rapports isotopiques du strontium (87Sr/86Sr) sont particulièrement utiles à cette fin, car ils varient géographiquement, surtout lorsqu’ils sont jumelés avec les rapports isotopiques stables de l’oxygène (δ18O), dont la variabilité est saisonnière. Ensemble, ces deux isotopes peuvent fournir des informations sur les habitudes de déplacement des animaux dans un paysage en fonction des saisons. Cependant, même si plusieurs études ont utilisé les valeurs 87Sr/86Sr et δ18O découlant des analyses des tissus séquentiellement formés à cette fin, peu d’analyses ont été effectuées chez les animaux modernes dont les habitudes de déplacement sont connues dans les régions de haute latitude. Dans cette étude pilote, nous avons séquentiellement échantillonné et analysé une deuxième molaire (M2) et deux troisièmes molaires (M3) de deux bisons (Bison bison bison) du troupeau de bisons du delta, troupeau qui réside dans l’intérieur de l’Alaska et dont les modèles de mobilité saisonnière sont connus et documentés. Les valeurs 87Sr/86Sr obtenues à partir des dents ont été comparées à un paysage isotopique de haute résolution 87Sr/86Sr pour la région et ont été jumelées aux analyses δ18O pour déterminer si les valeurs 87Sr/86Sr saisonnières correspondaient aux valeurs prévues pour les zones d’habitat saisonnières du bison. Les résultats indiquent que les valeurs 87Sr/86Sr et δ18O reflètent fidèlement les modèles connus de mobilité saisonnière du bison, et suggèrent que cette méthode pourrait servir à étudier les modèles de mobilité des bisons préhistoriques en Alaska et dans les régions de haute latitude environnantes

    Virus prevalence and genetic diversity across a wild bumblebee community

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    Viruses are key population regulators, but we have limited knowledge of the diversity and ecology of viruses. This is even the case in wild host populations that provide ecosystem services, where small fitness effects may have major ecological impacts in aggregate. One such group of hosts are the bumblebees, which have a major role in the pollination of food crops and have suffered population declines and range contractions in recent decades. In this study, we investigate the diversity of four recently discovered bumblebee viruses (Mayfield virus 1, Mayfield virus 2, River Liunaeg virus and Loch Morlich virus), and two previously known viruses that infect both wild bumblebees and managed honeybees (Acute bee paralysis virus and Slow bee paralysis virus) from isolates in Scotland. We investigate the ecological and environmental factors that determine viral presence and absence. We show that the recently discovered bumblebee viruses were more genetically diverse than the viruses shared with honeybees. Coinfection is potentially important in shaping prevalence: we found a strong positive association between River Liunaeg virus and Loch Morlich virus presence after controlling for host species, location and other relevant ecological variables. We tested for a relationship between environmental variables (temperature, UV radiation, wind speed and prevalence), but as we had few sampling sites, and thus low power for site-level analyses, we could not conclude anything regarding these variables. We also describe the relationship between the bumblebee communities at our sampling sites. This study represents a first step in the description of predictors of bumblebee infection in the wild

    Analysis of Cardiac Ion Channels to Understand Arrhythmias Which Lead to Sudden Cardiac Death

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    There are 300,000-400,000 fatalities attributed to sudden cardiac death every year in the U.S. due to a lack of sufficient research on mechanisms causing arrhythmias1. Malfunctions with the ion channels in the heart may lead to lethal arrhythmias. The purpose of this work is to study ion channels and evaluate malfunctions relative to normally functioning hearts. Plasmid insertion in E. coli assayed whether functional ion channels reach the membrane, and confocal fluorescent microscopy was used to illuminate cellular functionality. In addition, genetic analysis was used to determine the extent of hereditary factors in sudden cardiac death. Genes that encode for the voltage-gated sodium, potassium, and calcium ion channels were analyzed at the genetic level using isolated DNA samples and traditional Sanger sequencing methods to identify mutations that may be responsible for sudden cardiac death syndromes. For example, Long QT syndrome, Short QT syndrome, and Brugada syndrome are caused by mutations in these ion channels. Once these mutations are identified, genetic engineering techniques can be used in the generation of new heart cells from the stem cells found in somatic tissue. Generation of such heart cells is important because it could lead to the development of personalized treatment for degenerative diseases such as heart failure in the future. Rubart, M. et al., Mechanisms of Sudden Cardiac Death, 2005. J. clin. invest. 115(9):2305-2315
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