247 research outputs found

    Great Lakes Restoration Initiative Activities in Illinois to Reduce Canada Goose Impacts on Lake Michigan

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    The Great Lakes Restoration Initiative (GLRI), led by the Environmental Protection Agency, was created in 2010 to address threats to the Great Lakes region. A convenient year-round water source and abundant food source of managed turf grass has resulted in an overabundance of Canada Geese (Branta canadensis) in Chicago City Parks within the watershed of Lake Michigan. The anthropogenic mediated benefit to goose populations and their associated damages qualifies Canada geese in Chicago as native invaders-where a native species is human induced to behave similar to invasive species. The objective of this project is to provide a long-term strategy to protect vegetation and reduce non-point source contamination from entering the nearshore waters of Lake Michigan, and as a byproduct improve human enjoyment of the parks. To accomplish this goal, the U.S. Department of Agriculture’s Wildlife Services (WS) program in cooperation with the Chicago Park District (CPD) continued, for the sixth year, to manage overabundant Canada goose populations in CPD parks with funding provided by GLRI. Between 2011 and 2016, we applied food grade corn oil to all Canada goose nests found within 24 sensitive lakefront parks in Chicago and successfully reduced hatching success and subsequent fledging. The number of nests found and treated during 2012 through 2016 has consistently been less than during the initial year of egg oiling in 2011. In March 2016, we treated a total of 115 nests containing 676 eggs with corn oil to prevent hatching; compared to 159 nests and 892 eggs in 2011. We applied a chemical application of the Anthraquinone-based foraging repellent, FlightControl® PLUS (FCP) to the grass every 3 weeks in 6 parks in an attempt to discourage geese from foraging and loafing in locations that directly drain into the nearshore water of Lake Michigan. To gauge the effectiveness of the FCP applications, we performed goose presence/behavior surveys in the 6 treated parks. The surveys helped to obtain a better understanding of how many geese were utilizing the untreated and treated areas and how many of those geese were consuming grass on the FCP treated areas. The surveys demonstrated that more geese used untreated areas compared to treated areas of the parks. A total of 5,511 geese were observed (3,221 in the untreated areas and 2,290 in the treated areas) during the survey period. While geese may be present in the treated areas, only 40% of all geese consumed grass in treated areas. Alternatively, 58% of all geese present in the untreated areas consumed grass. The surveys also showed that FCP treatments became less effective each week post spraying. The mean number of geese present and feeding in the treated areas showed a diminishing effectiveness from the FCP spraying on the treated areas across weeks. The statistical results confirmed this strong week-post-spray by treatment interaction. 21 The disparity in numbers of geese actually consuming grass within the treated versus untreated areas reflects that the FCP treatments were effective at deterring geese from consuming grass in FCP treated areas, but did not necessarily result in the birds dispersing away from FCP treated vegetation. Future applications of FCP are recommended where high concentrations of geese congregate on sensitive habitats or in areas of high public use along the lakefront. Continued population management through egg oiling is recommended to help prevent further environmental contamination and soil erosion in this sensitive Lake Michigan environment

    The Probability of a Gene Tree Topology within a Phylogenetic Network with Applications to Hybridization Detection

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    Gene tree topologies have proven a powerful data source for various tasks, including species tree inference and species delimitation. Consequently, methods for computing probabilities of gene trees within species trees have been developed and widely used in probabilistic inference frameworks. All these methods assume an underlying multispecies coalescent model. However, when reticulate evolutionary events such as hybridization occur, these methods are inadequate, as they do not account for such events. Methods that account for both hybridization and deep coalescence in computing the probability of a gene tree topology currently exist for very limited cases. However, no such methods exist for general cases, owing primarily to the fact that it is currently unknown how to compute the probability of a gene tree topology within the branches of a phylogenetic network. Here we present a novel method for computing the probability of gene tree topologies on phylogenetic networks and demonstrate its application to the inference of hybridization in the presence of incomplete lineage sorting. We reanalyze a Saccharomyces species data set for which multiple analyses had converged on a species tree candidate. Using our method, though, we show that an evolutionary hypothesis involving hybridization in this group has better support than one of strict divergence. A similar reanalysis on a group of three Drosophila species shows that the data is consistent with hybridization. Further, using extensive simulation studies, we demonstrate the power of gene tree topologies at obtaining accurate estimates of branch lengths and hybridization probabilities of a given phylogenetic network. Finally, we discuss identifiability issues with detecting hybridization, particularly in cases that involve extinction or incomplete sampling of taxa

    Discordant identification of pediatric severe sepsis by research and clinical definitions in the SPROUT international point prevalence study

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    Introduction: Consensus criteria for pediatric severe sepsis have standardized enrollment for research studies. However, the extent to which critically ill children identified by consensus criteria reflect physician diagnosis of severe sepsis, which underlies external validity for pediatric sepsis research, is not known. We sought to determine the agreement between physician diagnosis and consensus criteria to identify pediatric patients with severe sepsis across a network of international pediatric intensive care units (PICUs). Methods: We conducted a point prevalence study involving 128 PICUs in 26 countries across 6 continents. Over the course of 5 study days, 6925 PICU patients <18 years of age were screened, and 706 with severe sepsis defined either by physician diagnosis or on the basis of 2005 International Pediatric Sepsis Consensus Conference consensus criteria were enrolled. The primary endpoint was agreement of pediatric severe sepsis between physician diagnosis and consensus criteria as measured using Cohen's ?. Secondary endpoints included characteristics and clinical outcomes for patients identified using physician diagnosis versus consensus criteria. Results: Of the 706 patients, 301 (42.6 %) met both definitions. The inter-rater agreement (? ± SE) between physician diagnosis and consensus criteria was 0.57 ± 0.02. Of the 438 patients with a physician's diagnosis of severe sepsis, only 69 % (301 of 438) would have been eligible to participate in a clinical trial of pediatric severe sepsis that enrolled patients based on consensus criteria. Patients with physician-diagnosed severe sepsis who did not meet consensus criteria were younger and had lower severity of illness and lower PICU mortality than those meeting consensus criteria or both definitions. After controlling for age, severity of illness, number of comorbid conditions, and treatment in developed versus resource-limited regions, patients identified with severe sepsis by physician diagnosis alone or by consensus criteria alone did not have PICU mortality significantly different from that of patients identified by both physician diagnosis and consensus criteria. Conclusions: Physician diagnosis of pediatric severe sepsis achieved only moderate agreement with consensus criteria, with physicians diagnosing severe sepsis more broadly. Consequently, the results of a research study based on consensus criteria may have limited generalizability to nearly one-third of PICU patients diagnosed with severe sepsis

    Phylogeography of Sardinian Cave Salamanders (Genus Hydromantes) Is Mainly Determined by Geomorphology

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    Detecting the factors that determine the interruption of gene flow between populations is key to understanding how speciation occurs. In this context, caves are an excellent system for studying processes of colonization, differentiation and speciation, since they represent discrete geographical units often with known geological histories. Here, we asked whether discontinuous calcareous areas and cave systems represent major barriers to gene flow within and among the five species of Sardinian cave salamanders (genus Hydromantes) and whether intraspecific genetic structure parallels geographic distance within and among caves. We generated mitochondrial cytochrome b gene sequences from 184 individuals representing 48 populations, and used a Bayesian phylogeographic approach to infer possible areas of cladogenesis for these species and reconstruct historical and current dispersal routes among distinct populations. Our results show deep genetic divergence within and among all Sardinian cave salamander species, which can mostly be attributed to the effects of mountains and discontinuities in major calcareous areas and cave systems acting as barriers to gene flow. While these salamander species can also occur outside caves, our results indicate that there is a very poor dispersal of these species between separate cave systems

    Coalescent Simulations Reveal Hybridization and Incomplete Lineage Sorting in Mediterranean Linaria

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    We examined the phylogenetic history of Linaria with special emphasis on the Mediterranean sect. Supinae (44 species). We revealed extensive highly supported incongruence among two nuclear (ITS, AGT1) and two plastid regions (rpl32-trnLUAG, trnS-trnG). Coalescent simulations, a hybrid detection test and species tree inference in *BEAST revealed that incomplete lineage sorting and hybridization may both be responsible for the incongruent pattern observed. Additionally, we present a multilabelled *BEAST species tree as an alternative approach that allows the possibility of observing multiple placements in the species tree for the same taxa. That permitted the incorporation of processes such as hybridization within the tree while not violating the assumptions of the *BEAST model. This methodology is presented as a functional tool to disclose the evolutionary history of species complexes that have experienced both hybridization and incomplete lineage sorting. The drastic climatic events that have occurred in the Mediterranean since the late Miocene, including the Quaternary-type climatic oscillations, may have made both processes highly recurrent in the Mediterranean flora

    Properties of Rubble-Pile Asteroid (101955) Bennu from OSIRIS-REx Imaging and Thermal Analysis

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    Establishing the abundance and physical properties of regolith and boulders on asteroids is crucial for understanding the formation and degradation mechanisms at work on their surfaces. Using images and thermal data from NASA's Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) spacecraft, we show that asteroid (101955) Bennu's surface is globally rough, dense with boulders, and low in albedo. The number of boulders is surprising given Bennu's moderate thermal inertia, suggesting that simple models linking thermal inertia to particle size do not adequately capture the complexity relating these properties. At the same time, we find evidence for a wide range of particle sizes with distinct albedo characteristics. Our findings imply that ages of Bennu's surface particles span from the disruption of the asteroid's parent body (boulders) to recent in situ production (micrometre-scale particles)

    The dynamic geophysical environment of (101955) Bennu based on OSIRIS-REx measurements

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    The top-shaped morphology characteristic of asteroid (101955) Bennu, often found among fast-spinning asteroids and binary asteroid primaries, may have contributed substantially to binary asteroid formation. Yet a detailed geophysical analysis of this morphology for a fast-spinning asteroid has not been possible prior to the Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) mission. Combining the measured Bennu mass and shape obtained during the Preliminary Survey phase of the OSIRIS-REx mission, we find a notable transition in Bennu’s surface slopes within its rotational Roche lobe, defined as the region where material is energetically trapped to the surface. As the intersection of the rotational Roche lobe with Bennu’s surface has been most recently migrating towards its equator (given Bennu’s increasing spin rate), we infer that Bennu’s surface slopes have been changing across its surface within the last million years. We also find evidence for substantial density heterogeneity within this body, suggesting that its interior is a mixture of voids and boulders. The presence of such heterogeneity and Bennu’s top shape are consistent with spin-induced failure at some point in its past, although the manner of its failure cannot yet be determined. Future measurements by the OSIRIS-REx spacecraft will provide insight into and may resolve questions regarding the formation and evolution of Bennu’s top-shape morphology and its link to the formation of binary asteroids
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