108 research outputs found

    Comparative analysis of the alien vascular flora of Sardinia and Corsica

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    This article provides a comparison of the vascular alien flora of Sardinia (Italy) and that of Corsica (France), both territories belonging to the Western Mediterranean biogeographic subregion. The study has recorded 598 (90 doubtful) alien taxa in Sardinia (18% of the total flora) while 553 (87 doubtful) in Corsica (17%); six are new report to Sardinia and 27 to Corsica. A total of 234 taxa are common to both islands. Neophytes are 344 taxa (68% of the total) in Sardinia and 399 taxa (73%) in Corsica. The invasive component includes 64 taxa in Sardinia (13% of the alien flora) and 99 taxa (21%) in Corsica, 33 of them common to both territories. The total 740 alien taxa of Sardinia and Corsica are included in 93 families; being Fabaceae the richest. The comparison of the biological spectrum reveals that phanerophytes (202 taxa, 40%) are the most represented in Sardinia and therophytes (149 taxa, 32%) in Corsica. A study of the geographical origin shows supremacy of the American element in Sardinia (170 taxa, 34%) and in Corsica (136 taxa, 29%). The majority of taxa arrived as a result of intentional human introductions, mainly for ornamental use (247 taxa, 49% in Sardinia; 208 taxa, 45% in Corsica). Seminatural, agricultural and synanthropic are the most occupied habitats. These data show the need for joint action to stem the increasingly worrying phenomenon of the alien flora in order to reduce the negative effects on natural habitats and native flora

    Seed Germination Ecophysiology of Acacia dealbata Link and Acacia mearnsii De Wild.: Two Invasive Species in the Mediterranean Basin

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    Acacia dealbata and A. mearnsii are two invasive species found in coastal, mountain, and riparian Mediterranean habitats. Seed biology and germination traits are important drivers of the competitive performance of plants and may significantly contribute to biological invasions. The seeds of Acacia s.l. have physical dormancy due to an impermeable epidermal layer. The aim of this study was to assess the germination capacity of scarified and non-scarified seeds of A. dealbata and A. mearnsii from different areas of the Mediterranean Basin. To test the seed imbibition capacity, the increase in mass was evaluated. Non-scarified seeds were tested at 15, 20, and 25 °C in light conditions. Scarified seeds were tested at 5, 10, 15, 20, and 25 °C and 25/10 °C in light and dark conditions. Scarified seeds increased in mass more than non-scarified seeds. Both species showed a higher germination capacity at 25 °C in non-scarified seeds; A. dealbata reached a germination maximum of 55%, while A. mearnsii reached 40%, showing a difference among these populations. Scarified seeds of both species reached germination percentages >95% at all temperatures except at 5 °C in dark conditions. Scarification was necessary to break dormancy and promote germination. The present study provides new knowledge about the seed ecology and germinative behaviour of the two Acacia species under different pre-treatment, temperature, and photoperiod regimes, contributing to the understanding of their invasive behaviour

    La flore vasculaire de l’île de Cavallo (archipel des Lavezzi, Corse) : diversité, intérêt biogéographique et conservation

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    This study provides the first detailed assessment of the vascular flora of the Cavallo Island and its three satellite islands or islets (Corsica, Bouchesde-Bonifacio). It is the Corsican island which has the highest floristic richness with 440 taxa (species and subspecies), all inventories combined. The current flora (i. e. occurring after 1990) includes 426 taxa, of which 371 indigenous and 55 exotic plants, introduced voluntarily or not by man. Of this total, 155 taxa (109 indigenous and 46 exotics) were never been reported on the Lavezzi archipelago. This high floristic richness, compared to other west-Mediterranean islands of similar size, is explained by the area of Cavallo island, the largest of the peri-corsican islands, and to the diversity of environments, including the presence of a permanent lake, the Greco lake. Cavallo Island and its islets contain 70 plant species of importance (i. e. endemic, rare, protected or threatened), eight of which were not currently inventoried. These surveys performed in 2013–2015 highlight the presence of some very rare plants in Corsica (Anacamptis morio subsp. longicornu, Callitriche brutia, Limonium bonifaciense, Limonium strictissimum) and infrequent endemics (Acis rosea, Bryonia marmorata, Crocus minimus, Serapias nurrica, Silene velutina) that were not known to the island. The strong human impact explains the presence of 55 introduced taxa and at least subspontaneous in the «natural environment», of which 50 had not yet been reported on the island. The results of this study are discussed in terms of (1) specific richness compared to other western Mediterranean islands of similar surface, (2) functional diversity (analysis of demographic strategies of Grime), (3) biogeographic originality and conservation issues in order to better preserve in the future this exceptional floristic heritage but for too long unrecognized.Cette étude dresse le premier bilan détaillé de la flore vasculaire de l’île Cavallo et de ses trois îles ou îlots annexes (Corse, Bouches-de-Bonifacio). Il s’agit de l’île satellite corse qui comporte la plus forte richesse floristique avec 440 taxons (espèces et sous-espèces) signalés, tous inventaires confondus. La flore actuelle (présence postérieure à 1990) s’élève à 426 taxons, dont 371 indigènes et 55 exotiques introduits volontairement ou non par l’homme. Parmi ce total, 155 taxons (109 indigènes et 46 exotiques) n’avaient jamais encore été signalés sur l’archipel des Lavezzi. Cette forte richesse floristique, comparée à celle d’autres îles ouest-méditerranéennes de taille voisine, est liée à la superficie de Cavallo, la plus vaste des îles péri-corses, et à la diversité des milieux dont la présence d’un plan d’eau permanent, l’étang du Greco. L’île Cavallo et ses îlots comportent 70 végétaux «patrimoniaux» (endémiques, rares, protégés ou menacés) dont 8 non revus actuellement. Les inventaires de 2013-2015 mettent notamment en évidence la présence de certains végétaux très rares en Corse (Anacamptis morio subsp., longicornu, Callitriche brutia, Limonium bonifaciense, Limonium strictissimum) et d’endémiques peu fréquents (Acis rosea, Bryonia marmorata, Crocus minimus, Serapias nurrica, Silene velutina) qui n’étaient pas connus de l’île. Les impacts anthropiques forts expliquent la présence de 55 taxons introduits et au moins subspontanés dans le «milieu naturel», dont 50 n’avaient pas été encore signalés sur l’île. Les résultats de cette étude sont discutés en terme (1) de richesse spécifique par rapport à des îles ouest-méditerranéennes de surfaces voisines, (2) de diversité fonctionnelle (analyse des stratégies démographiques de Grime), (3) d’originalité biogéographique et d’enjeux de conservation afin de mieux préserver à l’avenir ce patrimoine floristique exceptionnel mais resté trop longtemps méconnu.Médail Frédéric, Petit Yohan, Delage Alain, Paradis Guilhan, Hugot Laetitia. La flore vasculaire de l’île de Cavallo (archipel des Lavezzi, Corse) : diversité, intérêt biogéographique et conservation. In: Ecologia mediterranea, tome 43 n°2, 2017. Le patrimoine naturel de l'île de Cavallo (archipel des Lavezzi, Corse) : écologie, biogéographie et conservation. pp. 103-158

    Establishment and new hosts of the non-native seed beetle Stator limbatus (Coleoptera, Chrysomelidae, Bruchinae) on acacias in Europe

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    Stator limbatus is a phytophagous beetle native to warm regions of North and Central America, feeding on Fabaceae seeds and one of the most polyphagous species within the subfamily Bruchinae, here reported for the first time in Europe and on new hosts. Adult beetles emerged from Acacia spp. seeds collected in the islands of Corsica (France), and Sardinia (Italy). The wide presence in Sardinia and Corsica supports the hypothesis that this alien species was introduced several years ago. In both islands, S. limbatus emerged from Acacia mearnsii seeds, with infestation rates of up to 74.2 and 90.8% in 2019 and 2020, respectively. This seed beetle also emerged from two previously unreported host species, Acacia saligna and A. pycnantha, showing highest infestation rates of 4.0 and 95.1%, respectively. Both Acacia species are reported as new host associations with S. limbatus. Overall, seed infestation rates recorded in 2019 and 2020 indicate that S. limbatus is well established and that Mediterranean bioclimatic conditions are suitable for its population ncrease in size. This study lays the foundations for further research on known and potential host species and the spread and distribution of S. limbatus in Europe

    Observability analysis of power distribution systems with distributed energy resources using correlational measurements

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    Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019Cataloged from PDF version of thesis.Includes bibliographical references (pages 57-59).In this thesis, an observability analysis framework is proposed for power distribution systems. The framework analyzes the sufficiency of the available measurements for monitoring the system. In the areas of the network where sufficient sensors have been deployed, the complex voltage at the nodes may be estimated. The framework also provides a metric that quantifies the accuracy of these voltage estimates. Due to the cost of sensors and the size of distribution systems, it is frequently the case that the available measurements are insufficient for complete observability of the system. In this thesis, the author proposes the use of Correlational Measurements (CMs) for improving distribution system observability by leveraging correlation between loads and between Distributed Energy Resources (DERs). Load correlation due to class-residential, commercial, industrial, etc.- is captured via correlational load measurements, the first type of CM. Injection correlation of DERs-such as wind turbines located in proximity-is captured via correlational DER measurements, the second type of CM. This thesis presents the CM formulation and derives modified node voltage and branch current based state estimators (NVSE and BCSE) accommodating CMs. Additionally, this thesis contains an on-line parameter estimation scheme for CMs that improves the accuracy of state estimates over time. The observability analysis framework with CMs is demonstrated through simulations on the IEEE 123 Node Distribution Test Feeder. It is shown that the introduction of CMs leads to improved observability of the system with only a 0.7% decrease in state estimation accuracy for NVSE and a 0.5% increase in state estimation accuracy for BCSE.by Yohan M. John.S.M.S.M. Massachusetts Institute of Technology, Department of Mechanical Engineerin

    IMP simulated mock community data set

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    <p>This file contains the simulated mock (SM) metagenomic and metatranscriptomic dataset along with the original genomes used for simulation used within the article:</p> <p><strong>IMP: a reproducible pipeline for reference-independent integrated metagenomic and metatranscriptomic analyses</strong></p> <p>Shaman Narayanasamy<sup>†</sup>, Yohan Jarosz<sup>†</sup>, Emilie E.L. Muller, Cédric C. Laczny, Malte Herold, Anne Kaysen, Anna Heintz-Buschart, Nicolás Pinel, Patrick May, and Paul Wilmes<sup>*</sup></p> <p>Preprint: http://biorxiv.org/content/early/2016/02/10/039263</p> <p>The folder contains two subfolders (MG and MT), each containing the simulated metagenomic (MG) data and simulated metatranscriptomic (MT) data respectively. The files within these folders are in FASTQ format. The methods for generating these simulated data sets are described in the article.<br>  </p> <p>The genomes and the resulting simulated metatranscriptomic data was generated and analysed within the article:</p> <p><strong>Comparison of assembly algorithms for improving rate of metatranscriptomic functional annotation</strong></p> <p>Albi Celaj, Janet Markle, Jayne Danska and John Parkinson; 2014; doi:10.1186/2049-2618-2-39</p> <p> </p> <p>It was provided upon request by the first author Albi Celaj, with permission to share the data. Please cite the aforementioned publication if this simulated metatranscriptomic data is used data is used.</p&gt
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