3,910 research outputs found
Community impacts of anthropogenic disturbance: natural enemies exploit multiple routes in pursuit of invading herbivore hosts
No full textBackground: Biological invasions provide a window on the process of community assembly. In particular, tracking natural enemy recruitment to invading hosts can reveal the relative roles of coevolution (including local adaptation) and ecological sorting. We use molecular data to examine
colonisation of northern Europe by the parasitoid Megastigmus stigmatizans following invasions of its herbivorous oak gallwasp hosts from the Balkans. Local host adaptation predicts that invading gallwasp populations will have been tracked primarily by sympatric Balkan populations of M. stigmatizans (Host Pursuit Hypothesis). Alternatively, ecological sorting allows parasitoid
recruitment from geographically distinct populations with no recent experience of the invading hosts (Host Shift Hypothesis). Finally, we test for long-term persistence of parasitoids introduced via human trade of their hosts’ galls (Introduction Hypothesis).
Results: Polymorphism diagnostic of different southern refugial regions was present in both mitochondrial and nuclear microsatellite markers, allowing us to identify the origins of northern European invaded range M. stigmatizans populations. As with their hosts, some invaded range
populations showed genetic variation diagnostic of Balkan sources, supporting the Host Pursuit Hypothesis. In contrast, other invading populations had an Iberian origin, unlike their hosts innorthern Europe, supporting the Host Shift Hypothesis. Finally, both British and Italian M.
stigmatizans populations show signatures compatible with the Introduction Hypothesis from eastern Mediterranean sources.
Conclusions: These data reveal the continental scale of multi-trophic impacts of anthropogenic disturbance and highlight the fact that herbivores and their natural enemies may face very different constraints on range expansion. The ability of natural enemies to exploit ecologically-similar hosts with which they have had no historical association supports a major role for ecological sorting processes in the recent assembly of these communities. The multitude of origins of invading
natural enemy populations in this study emphasises the diversity of mechanisms requiring consideration when predicting consequences of other biological invasions or biological control introductions
Analytical treatment of the transient motion of inertial beams attached to coupling inertial resonators
No full textThis paper presents, for the first time, an analytical formulation to determine the transient response of an elastic beam possessing distributed inertia and connected to a coupling inertial resonator, represented by a gyroscopic spinner. The latter couples the transverse displacement components of the beam in the two perpendicular directions, thus producing roto-flexural vibrations. A detailed parametric study is presented that illustrates the effects of the beam’s distributed inertia and of the resonator’s characteristics. The limit case of massless beam is examined and it is shown that in some situations the distributed inertia in the beam should not be neglected. Analytical results are also validated by finite element computations. An illustration is also presented that demonstrates the effectiveness of using the considered inertial devices to mitigate hazardous vibrations in structural systems. It is envisaged that this paper may be useful in the analysis of flexural waveguides and metamaterials consisting of inertial elastic beam elements
Central nervous system tumors in pediatric population from 0 to 14 years
No full textIntroducción: Los tumores pediátricos primarios del sistema nervioso central (SNC), ocupan el segundo lugar en frecuencia, superados solamente por las neoplasias hematológicas. Objetivo: Realizar una revisión y análisis de la literatura médica existente sobre tumores del SNC en población entre los 0 y 14 años centrado en la epidemiologia, factores etiológicos, manifestaciones clÍnicas y diagnóstico. MetodologÍa: Se realizó una búsqueda en las bases de datos PubMed, MedlinePlus, BIREME y red interna de trabajos de grados y tesis de la Universidad Industrial de Santander. Además, se realizó revisión de las páginas de los entes gubernamentales encargados del registro epidemiológico sobre cáncer nacional e internacional. Resultados: Los tumores de SNC en la población pediátrica son la segunda causa de muerte infantil solo superado por la leucemia; tienen una clÍnica y factores etiológicos bien establecidos. La epidemiologÍa no difiere en el mundo. Los sÍntomas más frecuentes son vómito, cefalea, ataxia, sÍntomas visuales y alteraciones motoras. Los factores etiológicos más representativos son virus, sÍndromes genéticos, infecciones maternas y perinatales, exposición a radiación electromagnética e ionizante; algunos son muy discutidos como la presencia de trauma al momento del nacimiento. Además, existen documentados factores protectores tales como consumo de antioxidantes, frutas y verduras, e historia reportada de alergias. Conclusiones: El adecuado entrenamiento a los médicos de atención primaria en la identificación de los signos y sÍntomas para la sospecha y diagnóstico de los estadios iniciales de estos tumores pueden disminuir los Índices de mortalidad. [Nieves-Cuervo GM, Manrique-Hernández EF, Ojeda-Rincón SA, Galvis-Pabón S. Tumores del sistema nervioso central en población pediátrica entre 0 y 14 años. MedUNAB 2016; 19 (2): 124-133]Introduction: The primary pediatric tumors of the central nervous system (CNS) rank second in frequency, only surpassed by hematological malignancies. Objective. Conduct a review and analysis of existing literature on CNS tumors in population between 0 and 14 focused on the epidemiology, etiological factors, clinical manifestations, and diagnosis. Methodology: The search for articles was conducted using the databases PubMed, MedLinePlus, BIREME and intranet degrees and thesis work of the Universidad Industrial de Santander. Further review of the pages from government agencies in charge of epidemiological registry of cancer was made. Results: CNS tumors in pediatric population are the second leading cause of infant death second only to leukemia, have a clinic and etiological factors well established. The epidemiology don´t differs in the world. The most common symptoms are vomiting, headache, ataxia, visual symptoms and motor disturbances. The most representative etiologic factors are viruses, genetic syndromes, maternal and perinatal infections, exposure to electromagnetic and ionizing radiation, some others are discussed as the presence of trauma at birth. There are also documented protective factors such as consumption of antioxidant, fruits and vegetables, and reported history of allergies. Conclusions: The adequate training of primary care physicians in the identification of signs and symptoms for suspicion and diagnosis of the initial stages of these tumors can reduce mortality rates. [Nieves-Cuervo GM, Manrique-Hernández EF, Ojeda-Rincón SA, Galvis-Pabón S. Central nervous system tumors in pediatric population from 0 to 14 years. MedUNAB 2016; 19 (2): 124-133]
Self-compression of 4.9 µm pulses to sub-40 fs with 2 mJ energy in Zinc Sulfide
No full textNonlinear self-compression of few-cycle multi-mJ pulses at 4.9 µm in ZnS is presented. 80 fs input pulses are compressed to 37 fs with 2.1 mJ energy at a 1 kHz repetition rate. © 2024 The Author(s
Correction to: Chamoun et al., Bacterial pathogenesis and interleukin-17: interconnecting mechanisms of immune regulation, host genetics, and microbial virulence that influence severity of infection
No full textChamoun MN, Blumenthal A, Sullivan MJ, Schembri MA, Ulett GC. 2018. Bacterial pathogenesis and interleukin-17: interconnecting mechanisms of immune regulation, host genetics, and microbial virulence that influence severity of infection. Critical Reviews in Microbiology. https://doi.org/10.1080/1040841X.2018.1426556.
When the above article was first published online, the below three corrections were missed.
The author ‘Antje Blumenthal’ was wrongly affiliated to the affiliation “cSchool of Chemistry and Molecular Biosciences, and Australian Infectious Disease Research Centre, The University of Queensland, Brisbane, Australia”. Now this affiliation has been removed for this author.
The affiliation ‘bTranslational Research Institute, The University of Queensland Diamantina Institute, Woolloongabba, Australia’ of the author ‘Antje Blumenthal’ should read ‘bThe University of Queensland Diamantina Institute, Translational Research Institute, Brisbane, Australia’.
In Table 3, the sentence ‘Benefit of manipulating IL-17 levels to improve immunization strategies M. tuberculosis’ should read “Benefit of manipulating IL-17 levels to improve immunization strategies against M. tuberculosis”.No Full Tex
Generation of 22-mJ, 2.0-ps Pulses from a 1-kHz Ho:YLF Regenerative Chirped Pulse Amplifier
No full textWe report a CW-pumped Ho:YLF regenerative amplifier (RA) delivering pulses with 22.5-mJ energy and 2.0-ps duration at 1 kHz. The RA emitting at 2051 nm is broadband-seeded and implemented in a chirped pulse amplification system. © 2024 The Author(s
Transient response of a gyro-elastic structured medium: unidirectional waveforms and cloaking
No full textThe transient analysis of gyro-elastic structured media, composed of periodically placed masses interconnected by elastic rods and attached to gyroscopic spinners, is presented. The analysis is based on an asymptotic transient model, developed in this paper, that describes the interaction between a gyroscopic spinner and a mass embedded in a truss system. Several examples are given that illustrate the transient features of special dynamic phenomena, including unidirectional interfacial waves and highly localised waveforms. Two important applications of the model are also proposed, which demonstrate that gyro-elastic systems can be utilised to design an efficient structured topological insulator and a cloaking device for a discrete medium
A Bayesian framework to estimate diversification rates and their variation through time and space
No full textBackground: Patterns of species diversity are the result of speciation and extinction processes, and molecular phylogenetic data can provide valuable information to derive their variability through time and across clades. Bayesian Markov chain Monte Carlo methods offer a promising framework to incorporate phylogenetic uncertainty when estimating rates of diversification.
Results: We introduce a new approach to estimate diversification rates in a Bayesian framework over a distribution of trees under various constant and variable rate birth-death and pure-birth models, and test it on simulated phylogenies. Furthermore, speciation and extinction rates and their posterior credibility intervals can be estimated while accounting for non-random taxon sampling. The framework is particularly suitable for hypothesis testing using Bayes factors, as we demonstrate analyzing dated phylogenies of Chondrostoma (Cyprinids) and Lupinus (Fabaceae). In addition, we develop a model that extends the rate estimation to a meta-analysis framework in which different data sets are combined in a single analysis to detect general temporal and spatial trends in diversification.
Conclusions: Our approach provides a flexible framework for the estimation of diversification parameters and hypothesis testing while simultaneously accounting for uncertainties in the divergence times and incomplete taxon sampling
Pure-rotational 1D-CARS spatiotemporal thermometry with a single regenerative amplifier system
No full textWe report spatiotemporal pure-rotational coherent anti-Stokes Raman spectroscopy (CARS) in a one-dimensional imaging arrangement obtained with a single ultrafast regenerative amplifier system. The femtosecond pump/Stokes photon pairs, used for impulsive excitation, are delivered by an external compressor operating on a ∼35% beam split of the uncompressed amplifier output (2.5 mJ/pulse). The picosecond 1.2 mJ probe pulse is produced via the second-harmonic bandwidth compression (SHBC) of the ∼65% remainder of the amplifier output (4.5 mJ/pulse), which originates from the internal compressor. The two pump/Stokes and probe pulses are spatially, temporally, and repetition-wise correlated at the measurement, and the signal generation plane is relayed by a wide-field coherent imaging spectrometer onto the detector plane, which is refreshed at the same repetition rate as the ultrafast regenerative amplifier system. We demonstrate 1 kHz cinematographic 1D-CARS gas-phase thermometry across an unstable premixed methane/air flame-front, achieved with a single-shot precision <1% and accuracy <3%, 1.4 mm field of view, and an excellent <20 µm line-spread function.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Flight Performance and Propulsio
Factors associated with the contemplative stage of readiness to initiate osteoporosis treatment
No full textWe investigated the factors associated with readiness for initiating osteoporosis treatment in women at high risk of fracture. We found that women in the contemplative stage were more likely to report previously being told having osteoporosis or osteopenia, acknowledge concern about osteoporosis, and disclose prior osteoporosis treatment
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