190 research outputs found
Widespread horizontal transfer of the cerato-ulmin gene between Ophiostoma novo-ulmi and Geosmithia species
Socio-Ecological Interactions Promote Outbreaks of a Harmful Invasive Plant in an Urban Landscape
Urban landscapes often harbour organisms that harm people and threaten native biodiversity. These landscapes are characterized by differences in socioeconomic context, habitat suitability and patch connectedness. Identifying which spatial differences enable outbreaks of pests, pathogens and invasive species will improve targeted control efforts.
We tested hypotheses to explain the distribution and demography of puncturevine Tribulus terrestris, a human-dispersed invasive plant in Boise, a city in the western United States. We hypothesized an increase in puncturevine infestations near low-valued properties with a high proportion of bare ground, the species\u27 preferred microhabitat, that are well connected on the urban road network. To test these hypotheses, we collected data on the abundance, emergence and persistence of reproductive plants in transects spanning \u3e100 km of our study city. We then used hierarchical Bayesian models to evaluate the impacts of spatial covariates on puncturevine distribution and demography.
Bare ground cover consistently increased abundance, emergence and persistence of puncturevine, indicating the overarching importance of suitable establishment sites for this invasive species.
Property value had the strongest impact on puncturevine abundance and was the most important main effect in the model for puncturevine emergence. In both models, lower-valued properties had a higher risk of puncturevine occurrence.
The effects of road network connectivity depended on bare ground cover, with the highest predicted abundance and emergence of puncturevine in patches with low connectivity on the road network and high bare ground cover. Understanding these relationships will require data that can disentangle seed dispersal from establishment limitations
A low-cost 2-D video system can accurately and reliably assess adaptive gait kinematics in healthy and low vision subjects
3-D gait analysis is the gold standard but many healthcare clinics and research institutes would benefit from a system that is inexpensive and simple but just as accurate. The present study examines whether a low-cost 2-D motion capture system can accurately and reliably assess adaptive gait kinematics in subjects with central vision loss, older controls, and younger controls. Subjects were requested to walk up and step over a 10 cm high obstacle that was positioned in the middle of a 4.5 m walkway. Four trials were simultaneously recorded with the Vicon motion capture system (3-D system) and a video camera that was positioned perpendicular to the obstacle (2-D system). The kinematic parameters (crossing height, crossing velocity, foot placement, single support time) were calculated offline. Strong Pearson's correlations were found between the two systems for all parameters (average r = 0.944, all p < 0.001). Bland-Altman analysis showed that the agreement between the two systems was good in all three groups after correcting for systematic biases related to the 2-D marker positions. The test-retest reliability for both systems was high (average ICC = 0.959). These results show that a low-cost 2-D video system can reliably and accurately assess adaptive gait kinematics in healthy and low vision subjects
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Highly efficient separation of actinides from lanthanides by a phenanthroline-derived bis-triazine ligand
The synthesis, lanthanide complexation, and solvent ex- traction of actinide(III) and lanthanide(III) radiotracers from nitric acid solutions by a phenanthroline-derived quadridentate bis-triazine ligand are described. The ligand separates Am(III) and Cm(III) from the lanthanides with remarkably high efficiency, high selectivity, and fast extraction kinetics compared to its 2,2'-bipyridine counterpart. Structures of the 1:2 bis-complexes of the ligand with Eu(III) and Yb(III) were elucidated by X-ray crystallography and force field calculations, respec-tively. The Eu(III) bis-complex is the first 1:2 bis-complex of a quadridentate bis-triazine ligand to be characterized by crystallography. The faster rates of extraction were verified by kinetics measurements using the rotating membrane cell technique in several diluents. The improved kinetics of metal ion extraction are related to the higher surface activity of the ligand at the phase interface. The improvement in the ligand's properties on replacing the bipyridine unit with a phenanthroline unit far exceeds what was anticipated based on ligand design alone
A monograph of Aspergillus section Candidi
Aspergillus section Candidi encompasses white- or yellow-sporulating species mostly isolated from indoor and cave environments, food, feed,
clinical material, soil and dung. Their identification is non-trivial due to largely uniform morphology. This study aims to re-evaluate the species boundaries
in the section Candidi and present an overview of all existing species along with information on their ecology. For the analyses, we assembled a set of 113
strains with diverse origin. For the molecular analyses, we used DNA sequences of three house-keeping genes (benA, CaM and RPB2) and employed
species delimitation methods based on a multispecies coalescent model. Classical phylogenetic methods and genealogical concordance phylogenetic
species recognition (GCPSR) approaches were used for comparison. Phenotypic studies involved comparisons of macromorphology on four cultivation
media, seven micromorphological characters and growth at temperatures ranging from 10 to 45 °C. Based on the integrative approach comprising four
criteria (phylogenetic and phenotypic), all currently accepted species gained support, while two new species are proposed (A. magnus and A. tenebricus).
In addition, we proposed the new name A. neotritici to replace an invalidly described A. tritici. The revised section Candidi now encompasses nine species,
some of which manifest a high level of intraspecific genetic and/or phenotypic variability (e.g., A. subalbidus and A. campestris) while others are more uniform
(e.g., A. candidus or A. pragensis). The growth rates on different media and at different temperatures, colony colours, production of soluble pigments, stipe
dimensions and vesicle diameters contributed the most to the phenotypic species differentiation.Czech Ministry of Health, the Charles University Research Centre program no. 204069, Czech Academy of Sciences Long-term Research Development Project, the project of Charles University Grant Agency, the Japan Society for the Promotion of Science Postdoctoral Fellowships for Research in Japan, the Grant-in-aid for JSPS research fellow and the Future Leaders - African Independent Research fellowship programme.https://www.journals.elsevier.com/studies-in-mycologyam2023BiochemistryGeneticsMicrobiology and Plant Patholog
Unravelling species boundaries in the <i>Aspergillus viridinutans</i> complex (section <i>Fumigati</i>) opportunistic human and animal pathogens capable of interspecific hybridization
Evaluating assumptions of scales for subjective assessment of thermal environments – Do laypersons perceive them the way, we researchers believe?
International audienc
Phenylglyoxal dihydrazones as unexpected products in the synthesis of 1,2,4-triazines by interaction of α-bromoacetophenones and arylhydrazides
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