356 research outputs found
The New Zealand Thrush: An Extinct Oriole
The New Zealand Thrush, or Piopio, is an extinct passerine that was endemic to New Zealand. It has often been placed in its own family (Turnagridae), unresolved relative to other passerines, but affinities with thrushes, Australaian magpies, manucodes, whistlers, birds-of-paradise and bowerbirds has been suggested based on morphological data. An affinity with the bowerbirds was also indicated in an early molecular study, but low statistical support make this association uncertain. In this study we use sequence data from three nuclear introns to examine the phylogenetic relationships of the piopios. All three genes independently indicate an oriole (Oriolidae) affinity of the piopios, and the monophyly of the typical orioles (Oriolus), figbirds (Sphecotheres), and the piopios is strongly supported in the Bayesian analysis of the concatenated data set (posterior probability = 1.0). The exact placement of the piopios within Oriolidae is, however, more uncertain but in the combined analysis and in two of the gene trees the piopios are placed basal to the typical orioles while the third gene suggest a sister relationship with the figbirds. This is the first time an oriole affinity has been proposed for the piopios. Divergence time estimates for the orioles suggest that the clade originated ca 20 million years ago, and based on these estimates it is evident that the piopios must have arrived on New Zealand by dispersal across the Tasman Sea and not as a result of vicariance when New Zealand separated from Gondwana in the late Cretaceous
Phylogeny of Passerida (Aves: Passeriformes) based on nuclear and mitochondrial sequence data.
Abstract Passerida is a monophyletic group of oscine passerines that includes almost 3500 species (about 36%) of all bird species in the world. . Monophyly of their Sylvioidea could not be corroborated-these taxa falls either into a clade with wrens, gnatcatchers, and nuthatches, or one with, e.g., warblers, bulbuls, babblers, and white-eyes. The tits, penduline tits, and waxwings belong to Passerida but have no close relatives among the taxa studied herein
Spruce forest afforestation leading to increased Fe mobilization from soils
Increasing exports of Fe and DOC from soils, causing browning of freshwaters, have been reported in recent decades in many regions of the northern hemisphere. Afforestation, and in particular an increase of Norway spruce forest in certain regions, is suggested as a driver behind these trends in water chemistry. In this study, we tested the hypothesis that the gradual accumulation of organic soil layers in spruce forests, and subsequent increase in organic acid concentrations and acidity enhances mobilization of Fe. First generation Norway spruce stands of different ages (35, 61, 90 years) and adjacent arable control plots were selected to represent the effects of aging forest. Soil solutions were sampled from suction lysimeters at two depths (below organic soil layer and in mineral soil) during two years, and analyzed for Fe concentration, Fe speciation (XAS analysis), DOC, metals, major anions and cations. Solution Fe concentrations were significantly higher in shallow soils under older spruce stands (by 5- and 6-fold) than in control plots and the youngest forest. Variation in Fe concentration was best explained by variation in DOC concentration and pH. Moreover, Fe in all soil solutions was present as mononuclear Fe(III)-OM complexes, showing that this phase is dominating Fe translocation. Fe speciation in the soil was also analyzed, and found to be dominated by Fe oxides with minor differences between plots. These results confirmed that Fe mobilization, by Fe(III)-OM complexes, was higher from mature spruce stands, which supports that afforestation with spruce may contribute to rising concentrations of Fe in surface waters
Highly porous flame-retardant and sustainable biofoams based on wheat gluten and in situ polymerized silica
Wheat gluten from ethanol production is presented as flame-retardant silica hybrid biofoams for insulation. The porosity of 90% and self-extinguishing nature make them an attractive alternative to petroleum-based foams.</p
Stability of flux vacua in the presence of charged black holes
In this letter we consider a charged black hole in a flux compactification of
type IIB string theory. Both the black hole and the fluxes will induce
potentials for the complex structure moduli. We choose the compact dimensions
to be described locally by a deformed conifold, creating a large hierarchy. We
demonstrate that the presence of a black hole typically will not change the
minimum of the moduli potential in a substantial way. However, we also point
out a couple of possible loop-holes, which in some cases could lead to
interesting physical consequences such as changes in the hierarchy.Comment: 14 pages. Published versio
Monitoring of dabigatran anticoagulation and its reversal in vitro by thrombelastography.
Dabigatran etexilate, a pro-drug of a direct thrombin inhibitor, was approved a few years ago for non-valvular atrial fibrillation and deep venous thrombosis. Rapid monitoring of the dabigatran level is essential in trauma and bleeding patients but the traditional plasma-based assays may not sufficiently display the effect. Furthermore, no antidote exists and reversal of the anticoagulant effect is impossible or difficult. The present study investigated the in vitro effect of dabigatran on whole blood thromboelastography (TEG) and its reversal by recombinant activated factor VII and prothrombin complex concentrate
Phylogenetic definitions for 25 higher-level clade names of birds
Knowledge of the higher-level phylogenetic relationships of birds has grown substantially during the past two decades due to the application of genomic data. However, the nomenclature of higher-level taxa has not become more stable, due to the lack of regulation of taxon names above the level of superfamily by the ICZN, and the usage of rank-based nomenclature, which is not tied to clades in a phylogeny. Lack of regulation and the instability of rank-based nomenclature impede effective communication among systematists. Here we review support for higher-level avian clades using a set of 10 phylogenomic data sets, and identify clades that are supported by congruency of at least four of these. We provide formal definitions of the names of these clades based on the rules of the recently published PhyloCode. The names of 25 clades are here defined using minimum-crown-clade (n = 23), minimum-clade (n = 1) and maximum-crown-clade (n = 1) definitions. Four new names are introduced here: Dinocrypturi, Pteroclimesites, Musophagotides and Pelecanes. We also review diagnostic apomorphies of the relevant clades, and identify known synonyms and homonyms. By establishing a formal link between higher-level taxon names and well-supported phylogenetic hypotheses, our phylogenetic definitions will provide a solid basis for the stabilization of avian higher-level nomenclature
Hybridization of Atlantic puffins in the Arctic coincides with 20th-century climate change
The Arctic is experiencingthe fastest rates of globalwarming,leadingto shiftsin the distributionof its biotaandincreasingthe potentialfor hybridization. However, genomicevidenceof recenthybridization events in theArctic remainsunexpectedlyrare. Here, we use whole-genomesequencingof contemporary and 122-year-oldhistoricalspecimensto investigate the originof an Arctic hybridpopulation of Atlanticpuffins(Fr aterculaarctica)on Bjørnøya, Norway. We show that the hybridization between the High Arctic, large-bodiedsubspeciesF. a. naumanniand the temperate, smaller-sizedsubspeciesF. a. arcticabeganas recentlyas six generationsagodue to an unexpectedsouthward rangeexpansionofF. a. naumanni.Moreover, we find a significanttemporalloss of geneticdiversityacross Arctic and temperate puffinpopulations.Our observationsprovide compellinggenomicevidenceof the impacts of recentdistributionalshiftsand loss of diversityin Arctic communitiesduringthe 20th century.publishedVersio
Deforming, revolving and resolving - New paths in the string theory landscape
In this paper we investigate the properties of series of vacua in the string
theory landscape. In particular, we study minima to the flux potential in type
IIB compactifications on the mirror quintic. Using geometric transitions, we
embed its one dimensional complex structure moduli space in that of another
Calabi-Yau with h^{1,1}=86 and h^{2,1}=2. We then show how to construct
infinite series of continuously connected minima to the mirror quintic
potential by moving into this larger moduli space, applying its monodromies,
and moving back. We provide an example of such series, and discuss their
implications for the string theory landscape.Comment: 41 pages, 5 figures; minor corrections, published versio
Extended Haplotypes in the Growth Hormone Releasing Hormone Receptor Gene (GHRHR) Are Associated with Normal Variation in Height
Mutations in the gene for growth hormone releasing hormone receptor (GHRHR) cause isolated growth hormone deficiency (IGHD) but this gene has not been found to affect normal variation in height. We performed a whole genome linkage analysis for height in a population from northern Sweden and identified a region on chromosome 7 with a lod-score of 4.7. The GHRHR gene is located in this region and typing of tagSNPs identified a haplotype that is associated with height (p = 0.00077) in the original study population. Analysis of a sample from an independent population from the most northern part of Sweden also showed an association with height (p = 0.0039) but with another haplotype in the GHRHR gene. Both haplotypes span the 3′ part of the GHRHR gene, including the region in which most of the mutations in IGHD have been located. The effect size of these haplotypes are larger than that of any gene previously associated with height, which indicates that GHRHR might be one of the most important genes so far identified affecting normal variation in human height
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