86 research outputs found

    Incongruent phylogenetic hypotheses and character conflicts in morphology : the root and early branches of the hexapodan tree

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    Before the turn of the millenium the investigation of phylogenetic relationships was revolutionized by two major inputs, the use of molecular sequence data for phylogenetic reconstruction, paralleled by the sophistication of computer aided reconstruction methods. The ever growing number of data however did not only result in clarifications of open questions, but brought forth a number of new conflicting phylogenetic hypotheses. Sometimes they are wrongly referred to as conflicts between morphological and molecular approaches, which sporadically even culminated in the rejection of the usefulness of one of the two approaches (e.g. Scotland et al 2003). These scientists overlook the great advantage of having two a priori largely independent data sets (Wägele 2001) which in a synthetic way enable the greatest progress in phylogenetic research. However, solely putting data together will not suffice to choose among conflicting hypotheses. The increasing number of conflicts necessitates approaches that go beyond mere data congruence, but searching for the possible reasons of conflicts. In the present paper, problems in the reconstruction of the phylogenetic origin of Hexapoda, as well as of the early branchings within the Hexapoda, will exemplify approaches of critical re-evaluation and testing of data used in morphological data matrices for phylogenetic analyses. The early cladogenetic events of hexapods are especially suited for such a discussion for several reasons. The hexapods, as the most species-rich group of organisms, look back at a long and multi-faceted history of taxonomic and phylogenetic studies, culminating in a number of conflicting hypotheses. Triggered by incongruences with morphological analyses the reconstruction of the hexapodan roots likewise became a hot-spot of molecular research activities during^the last two decades. Furthermore the phylogenetic positions of the oldest lineages branching off within the hexapodan clade, the Diplura, Protura and Collembola, are in particular very difficult to reconstruct. While at least the latter two are well defined by morphological autapomorphies their phylogenetic position could not be reconstructed unambiguously, since their morphology seems highly derived with respect to the hexapodan ground pattern.Angestoßen durch molekulare Untersuchungen sind die Verwandtschaftsverhältnisse der Großgruppen der Arthropoden in der letzten Dekade ein Hotspot der phylogenetischen Diskussion geworden. Ein heiß diskutiertes Thema ist die Frage nach der Monophylie der Insekten. Die in diesem Zusammenhang besonders interessanten „Ur-Insekten“ bilden eine morphologisch sehr heterogene Gruppe von primär flügellosen Insekten. Während die Annahme verwandtschaftlicher Beziehungen der Archaeognatha und Zygentoma zu den Pterygota (Ectognatha) breite Unterstützung finden, gibt es widersprüchliche Hypothesen hinsichtlich der phylogenetischen Stellung der Collembola, Protura und Diplura. Zu heftigen Diskussionen haben die Analysen mitochondrialer Gene durch Nardi et al. (2003) geführt. In den rekonstruierten Bäumen sind die Ectognatha näher verwandt mit Crustaceen als mit Collembolen, wodurch die Hexapoden eine paraphyletische Gruppierung werden. Dieser Befund hat eine Flut von neuen molekularen Untersuchungen ausgelöst und nahezu alle denkbaren Kombinationen der Verwandtschaftsbeziehungen zwischen Collembola, Protura, Diplura und Ectognatha haben Unterstützung gefunden. Kann die Morphologie zur Klärung dieser phylogenetischen Konflikte entscheidend beitragen? Sind die Hexapoden wirklich ein Monophylum oder ist die Hexapodie mehrfach unabhängig voneinander entstanden? Nach Diskussion ausgewählter Konflikte zur phylogenetischen Stellung der verschiedenen „Ur-Insekten“ werden anhand eigener Untersuchungen exemplarisch einige Probleme morphologischer Datensätze in der modernen stammesgeschichtlichen Forschung aufgezeigt und entsprechende Lösungsmöglichkeiten diskutiert

    Influence of Melt-Pool Stability in 3D Printing of NdFeB Magnets on Density and Magnetic Properties

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    The current work presents the results of an investigation focused on the influence of process parameters on the melt-track stability and its consequence to the sample density printed out of NdFeB powder. Commercially available powder of Nd7.5Pr0.7Fe75.4Co2.5B8.8Zr2.6Ti2.5 alloy was investigated at the angle of application in selective laser melting of permanent magnets. Using single track printing the stability of the melt pool was investigated under changing process parameters. The influence of changing laser power, scanning speed, and powder layer thickness on density, porosity structure, microstructure, phase composition, and magnetic properties were investigated. The results showed that energy density coupled with powder layer thickness plays a crucial role in melt-track stability. It was possible to manufacture magnets of both high relative density and high magnetic properties. Magnetization tests showed a significant correlation between the shape of the demagnetization curve and the layer height. While small layer heights are beneficial for sufficient magnetic properties, the remaining main parameters tend to affect the magnetic properties less. A quasi-linear correlation between the layer height and the magnetic properties remanence (Jr), coercivity (HcJ) and maximum energy product ((BH)max) was found

    Reliability and sensitivity to change of the bristol rheumatoid arthritis fatigue scales

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    Objective. To examine the reliability (stability) and sensitivity of the Bristol Rheumatoid Arthritis Fatigue scales (BRAFs) and patient-reported outcome measures (PROMs) developed to capture the fatigue experience. The Multi-Dimensional Questionnaire (BRAF-MDQ) has a global score and four subscales (Physical Fatigue, Living with Fatigue, Cognitive Fatigue and Emotional Fatigue), while three numerical rating scales (BRAF-NRS) measure fatigue Severity, Effect and Coping. Methods. RA patients completed the BRAFs plus comparator PROMs. Reliability (study 1): 50 patients completed questionnaires twice. A same-day test-retest interval (minimum 60 min) ensured both time points related to the same 7 days, minimizing the capture of fatigue fluctuations. Reliability (study 2): 50 patients completed the same procedure with a re-worded BRAF-NRS Coping. Sensitivity to change (study 3): 42 patients being given clinically a single high dose of i.m. glucocorticoids completed questionnaires at weeks 0 and 2.Results. The BRAF-MDQ, its subscales and the BRAF-NRS showed very strong reliability (r = 0.82-0.95). BRAF-NRS Coping had lower moderate reliability in both wording formats (r = 0.62, 0.60). The BRAF-MDQ, its subscales and the BRAF-NRS Severity and Effect were sensitive to change, with effect sizes (ESs) of 0.33-0.56. As hypothesized, the BRF-NRS Coping was not responsive to the pharmaceutical intervention (ES 0.05). Preliminary exploration suggests a minimum clinically important difference of 17.5% for improvement and 6.1% for fatigue worsening. Conclusion. The BRAF scales show good reliability and sensitivity to change. The lack of BRAF-NRS Coping responsiveness to medication supports the theory that coping with fatigue is a concept distinct from severity and effect that is worth measuring separately. © The Author 2013. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved

    The 2018 European heatwave led to stem dehydration but not to consistent growth reductions in forests

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    Publisher Copyright: © 2022, The Author(s).Heatwaves exert disproportionately strong and sometimes irreversible impacts on forest ecosystems. These impacts remain poorly understood at the tree and species level and across large spatial scales. Here, we investigate the effects of the record-breaking 2018 European heatwave on tree growth and tree water status using a collection of high-temporal resolution dendrometer data from 21 species across 53 sites. Relative to the two preceding years, annual stem growth was not consistently reduced by the 2018 heatwave but stems experienced twice the temporary shrinkage due to depletion of water reserves. Conifer species were less capable of rehydrating overnight than broadleaves across gradients of soil and atmospheric drought, suggesting less resilience toward transient stress. In particular, Norway spruce and Scots pine experienced extensive stem dehydration. Our high-resolution dendrometer network was suitable to disentangle the effects of a severe heatwave on tree growth and desiccation at large-spatial scales in situ, and provided insights on which species may be more vulnerable to climate extremes.Peer reviewe

    The 2018 European heatwave led to stem dehydration but not to consistent growth reductions in forests

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    Heatwaves exert disproportionately strong and sometimes irreversible impacts on forest ecosystems. These impacts remain poorly understood at the tree and species level and across large spatial scales. Here, we investigate the effects of the record-breaking 2018 European heatwave on tree growth and tree water status using a collection of high-temporal resolution dendrometer data from 21 species across 53 sites. Relative to the two preceding years, annual stem growth was not consistently reduced by the 2018 heatwave but stems experienced twice the temporary shrinkage due to depletion of water reserves. Conifer species were less capable of rehydrating overnight than broadleaves across gradients of soil and atmospheric drought, suggesting less resilience toward transient stress. In particular, Norway spruce and Scots pine experienced extensive stem dehydration. Our high-resolution dendrometer network was suitable to disentangle the effects of a severe heatwave on tree growth and desiccation at large-spatial scales in situ, and provided insights on which species may be more vulnerable to climate extremes

    Global transpiration data from sap flow measurements : the SAPFLUXNET database

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    Plant transpiration links physiological responses of vegetation to water supply and demand with hydrological, energy, and carbon budgets at the land-atmosphere interface. However, despite being the main land evaporative flux at the global scale, transpiration and its response to environmental drivers are currently not well constrained by observations. Here we introduce the first global compilation of whole-plant transpiration data from sap flow measurements (SAPFLUXNET, https://sapfluxnet.creaf.cat/, last access: 8 June 2021). We harmonized and quality-controlled individual datasets supplied by contributors worldwide in a semi-automatic data workflow implemented in the R programming language. Datasets include sub-daily time series of sap flow and hydrometeorological drivers for one or more growing seasons, as well as metadata on the stand characteristics, plant attributes, and technical details of the measurements. SAPFLUXNET contains 202 globally distributed datasets with sap flow time series for 2714 plants, mostly trees, of 174 species. SAPFLUXNET has a broad bioclimatic coverage, with woodland/shrubland and temperate forest biomes especially well represented (80 % of the datasets). The measurements cover a wide variety of stand structural characteristics and plant sizes. The datasets encompass the period between 1995 and 2018, with 50 % of the datasets being at least 3 years long. Accompanying radiation and vapour pressure deficit data are available for most of the datasets, while on-site soil water content is available for 56 % of the datasets. Many datasets contain data for species that make up 90 % or more of the total stand basal area, allowing the estimation of stand transpiration in diverse ecological settings. SAPFLUXNET adds to existing plant trait datasets, ecosystem flux networks, and remote sensing products to help increase our understanding of plant water use, plant responses to drought, and ecohydrological processes. SAPFLUXNET version 0.1.5 is freely available from the Zenodo repository (https://doi.org/10.5281/zenodo.3971689; Poyatos et al., 2020a). The "sapfluxnetr" R package - designed to access, visualize, and process SAPFLUXNET data - is available from CRAN.Peer reviewe

    Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

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    Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts

    Linguistic diversity and legal determinacy? : the principle of linguistic equality in European Community law

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    Award date: 20 October 1999Supervisor: Prof. Yota KravaritouPDF of thesis uploaded from the Library digitised archive of EUI PhD theses completed between 2013 and 201

    Examen Examinis Pieriani, Das ist/ Schulfürung und Abfertigung deß vermeinten Examinis, so Urbanus Pierius ... wider die Leichpredigt/ so dem entheupten D. Nicolao Krellen nachgehalte[n] ... worden ...

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    Gestellet durch Die drey Prediger/ so auff Churfürstlichen Befehlich bey dem gerechtfertigten D. Krellen auffgewartet haben [Nicolaus Blumius Pastor Dohnensis, ... M. Tobias Rudolff Dresdensis, ... Adam Mollerus Dresdensis ...]Verf. sind Unterzeichn. des Vorw

    Morphological and Genetic Analysis of the Acerentomon doderoi Group (Protura: Acerentomidae) with Description of A. christiani sp. nov.

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    Acerentomon christiani sp. nov. is described from Vienna, Austria. The new species is a member of the "doderoi" group, characterized by the presence of seta x on tergite VII. It is most similar to A. gallicum, A. brevisetosum and A. tenuisetosum, but differs from these species in the length of foretarsal sensillum c and certain other chaetotaxic measurements and indices. In addition to the morphological description, the DNA barcoding region of the mitochondrial cytochrome c oxidase subunit 1 gene (COI) and the 28S ribosomal RNA of the new species are provided. The morphological characters and the barcode of the new species are discussed in comparison to those of other Acerentomon species. An identification key to all known Acerentomon spp. of the "doderoi" group is given
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