117 research outputs found
Network design: Taxi Planning
The effect of managing aircraft movements on the airportâs ground is an important tool that can alleviate the delays of flights, specially in peak hours or congested situations. Although some strategic design decisions regarding aeronautical and safety aspects have a main impact on the airportâs topology, there exists a number of other additional factors that must be evaluated according to the on ground operations, i.e. previous to the taking-off or after landing. Among these factors one can consider capacities at waiting points and directions of some corridors. These factors are related to the demand situation of a given period and influence the aircraftâs routing on the ground or short term Taxi Planning problem (or TP-S). While the TP-S problem studies the aircraft routing and scheduling on the airportâs ground under a dynamic point of view, this paper presents a Taxi Planning network design model (or TPND), attending to these additional factors of the airportâs topology and the conflicting movements of the aircraft on them with the same modelling approach used in the TP-S problem. The TPND model is formulated as a binary multicommodity network flow problem with additional side constraints under a multiobjective approach. The side constraints included are the classical limitations due to capacity and also as a distinctive approach, constraints that restrict the interference of aircraft in order to decrease the intervention of human controllers during the operations or increase their safety margins. The multiobjective approach adopted for the TPND model balances conflicting objectives: airportâs throughput, travel times, safety of operations and costs. In the paper computational results are included on two test airports solving the TPND model by âBranch and Boundâ showing the effect of the conflicting objectives in the design decisions
Taxi Planner Optimization: A Management Tool
This work introduces taxi planning optimization (TPO) as a methodology to guide airport surface management operations. The optimization model represents competing aircraft using limited ground resources. TPO improves aircraft taxiing routes and their schedule in situations of congestion, minimizing overall taxiing time (TT), and helping taxi planners to meet prespecified goals such as compliance with take-off windows, TT limits, and trajectory conflicts. By considering all simultaneous trajectories during a given planning horizon, TPO's estimation of TT from the stand to the runways improves over current planning methods. The operational optimization model is a large-scale space-time multi-commodity network with capacity constraints. In addition to its natural use as a real-time taxi planning tool, a number of TPO variants can be used for design purposes, such as expansion of new infrastructure. TPO is demonstrated using Madrid-Barajas as test airport
The clinical effectiveness and cost effectiveness of clozapine for inpatients with severe borderline personality disorder (CALMED study): A randomised placebo-controlled trial.
Background: Data from case series suggest that clozapine may benefit inpatients with borderline personality disorder (BPD), but randomised trials have not been conducted. Methods: Multicentre, double-blind, placebo-controlled trial. We aimed to recruit 222 inpatients with severe BPD aged 18 or over, who had failed to respond to other antipsychotic medications. We randomly allocated participants on a 1:1 ratio to receive up to 400mg of clozapine per day or an inert placebo using a remote web-based randomisation service. The primary outcome was total score on the Zanarini Rating scale for Borderline Personality Disorder (ZAN-BPD) at six months. Secondary outcomes included self-harm, aggression, resource use and costs, side effects and adverse events. We used a modified intention to treat analysis (mITT) restricted to those who took one or more dose of trial medication, using a general linear model fitted at six months adjusted for baseline score, allocation group and site. Results: The study closed early due to poor recruitment and the impact of the COVID-19 pandemic. Of 29 study participants, 24 (83%) were followed up at six months, of whom 21 (72%) were included in the mITT analysis. At six months, 11 (73%) participants assigned to clozapine and 6 (43%) of those assigned to placebo were still taking trial medication. Adjusted difference in mean total ZAN-BPD score at six months was -3.86 (95% Confidence Intervals = -10.04 to 2.32, p=0.22). There were 14 serious adverse events; six in the clozapine arm and eight in the placebo arm of the trial. There was little difference in the cost of care between groups. Interpretation: We recruited insufficient participants to test the primary hypothesis. The study findings highlight problems in conducting placebo-controlled trials of clozapine and in using clozapine for people with BPD, outside specialist inpatient mental health units. Trial registration ISRCTN18352058. https://doi.org/10.1186/ISRCTN1835205
PHYSICAL, MORPHOLOGICAL PROPERTIES AND RAMAN SPECTROSCOPY OF CHESTNUT BLIGHT DISEASED CASTANEA SATIVA MILL. WOOD
A New Species of Saphonecrus (Hymenoptera, Cynipoidea) Associated With Plant Galls on Castanopsis (Fagaceae) in China
A new cynipid species, Saphonecrus hupingshanensis Liu, Yang, et Zhu, sp. nov. (Hymenoptera: Cynipidae: Synergini), is described from China. This is the first species of the inquilinous tribe Synergini ever known to have an association with chinquapins (Fagaceae: Castanopsis). The biology and implication to species diversity of Cynipidae in eastern and southeast Asia are discussed
On the Origin and Spread of the Scab Disease of Apple: Out of Central Asia
Background Venturia inaequalis is an ascomycete fungus responsible for apple scab, a disease that has invaded almost all apple growing regions worldwide, with the corresponding adverse effects on apple production. Monitoring and predicting the effectiveness of intervention strategies require knowledge of the origin, introduction pathways, and population biology of pathogen populations. Analysis of the variation of genetic markers using the inferential framework of population genetics offers the potential to retrieve this information. Methodology/Principal Findings Here, we present a population genetic analysis of microsatellite variation in 1,273 strains of V. inaequalis representing 28 orchard samples from seven regions in five continents. Analysis of molecular variance revealed that most of the variation (88%) was distributed within localities, which is consistent with extensive historical migrations of the fungus among and within regions. Despite this shallow population structure, clustering analyses partitioned the data set into separate groups corresponding roughly to geography, indicating that each region hosts a distinct population of the fungus. Comparison of the levels of variability among populations, along with coalescent analyses of migration models and estimates of genetic distances, was consistent with a scenario in which the fungus emerged in Central Asia, where apple was domesticated, before its introduction into Europe and, more recently, into other continents with the expansion of apple growing. Across the novel range, levels of variability pointed to multiple introductions and all populations displayed signatures of significant post-introduction increases in population size. Most populations exhibited high genotypic diversity and random association of alleles across loci, indicating recombination both in native and introduced areas. Conclusions/Significance Venturia inaequalis is a model of invasive phytopathogenic fungus that has now reached the ultimate stage of the invasion process with a broad geographic distribution and well-established populations displaying high genetic variability, regular sexual reproduction, and demographic expansion.Contexte Venturia inaequalis est un champignon ascomycete responsable de la tavelure du pommier, une maladie qui a envahi presque toutes les rĂ©gions du monde oĂč le pommier est cultivĂ© posant ainsi de graves problĂšmes en production. PrĂ©venir et enrayer efficacement la rĂ©ussite dâun tel succĂšs invasif nĂ©cessite des connaissances approfondies sur lâorigine, les voies dâintroduction, la biologie et la gĂ©nĂ©tique de ces populations invasives. En utilisant le potentiel dâinfĂ©rence de la gĂ©nĂ©tique des populations, lâanalyse de la variation de marqueurs gĂ©nĂ©tiques offre la possibilitĂ© dâaccĂ©der Ă ces informations. MĂ©thodologie et Principaux rĂ©sultats Ici nous prĂ©sentons lâanalyse de donnĂ©es microsatellites obtenues pour 1273 souches de V. inaequalis provenant de 28 vergers prĂ©levĂ©es dans 7 rĂ©gions sur les 5 continents. Lâanalyse de la variance molĂ©culaire rĂ©vĂšle que 88% de la variation se retrouve dans les vergers Ă©chantillonnĂ©s, ce qui est compatible avec dâimportantes migrations historiques du champignon entre et Ă lâintĂ©rieur mĂȘme des rĂ©gions. MalgrĂ© cette trĂšs faible structuration des populations, les diffĂ©rentes analyses de clustering mettent en Ă©vidence un partage des populations en groupes sĂ©parĂ©s correspondant Ă leur origine gĂ©ographique, montrant ainsi que chaque rĂ©gion hĂ©berge une population distincte du champignon. Ensemble, les rĂ©sultats obtenus sur la comparaison du niveau de variabilitĂ© entre populations, les analyses de coalescence et les modĂšles de migration testĂ©s plaident en faveur dâun scĂ©nario dans lequel le champignon aurait Ă©mergĂ© dâAsie Centrale, oĂč le pommier a Ă©tĂ© domestiquĂ©, avant dâĂȘtre introduit en Europe puis plus rĂ©cemment dans les autres continents suite Ă lâexpansion de la culture du pommier. Les niveaux de variabilitĂ© indiquent que ces territoires ont subi des introductions multiples et que les populations portent toutes des signatures rĂ©vĂ©lant de fortes expansions dĂ©mographiques aprĂšs leur introduction. Enfin, la forte diversitĂ© gĂ©notypique des populations et lâassociation alĂ©atoire des allĂšles entre loci suggĂšrent que le champignon prĂ©sente une reproduction sexuĂ©e rĂ©guliĂšre Ă la fois dans les rĂ©gions oĂč il a Ă©tĂ© introduit et dans sa rĂ©gion native. Conclusion et PortĂ©e. Venturia inaequalis est un modĂšle de champignons phytopathogĂšne invasif qui a maintenant atteint le stade ultime du processus invasif, câest Ă dire une trĂšs large distribution gĂ©ographique par des populations bien Ă©tablies montrant une grande diversitĂ© gĂ©nĂ©tique, une reproduction sexuĂ©e rĂ©guliĂšre et une histoire dâexpansion dĂ©mographique
Mycorrhization of fagaceae forests within mediterranean ecosystems
Mediterranean Fagaceae forests are valuable due to their ecological and socioeconomic aspects. Some profitable plant species, such as Castanea (timber and chestnut), Quercus (timber and cork), and Fagus (timber), encounter in this habitat the excellent edaphoclimatic conditions to develop. All Fagaceae plants are commonly associated to ECM fungal species, which are found in these forests in quite stable communities, mainly enriched in Russulaceae and Telephoraceae species. Currently, the Mediterranean Basin is considered as one of the global biodiversity hotspots, since many of their endemic plant species are not found elsewhere and are now under threat. Due to climate changing and introduction of disease agents, Fagaceae forests are facing an adaptation challenge to both biotic and abiotic threats. Although ECM communities are highly disturbed by climate factors and tree disease incidence, they could play an important role in increasing water availability to the plant and also improving plant tree defense against pathogens. Recent advances, namely, on genomics and transcriptomics, are providing tools for increasing the understanding of Fagaceae mycorrhization process and stress responses to biotic and abiotic stresses. Such studies can provide new information for the implementation of the most adequate management policies for protecting threaten Mediterranean forests.info:eu-repo/semantics/publishedVersio
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