6,264 research outputs found

    Canonical non-symmetrical correspondence analysis: an alternative in constrained ordination

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    Canonical non-symmetrical correspondence analysis is developed as an alternative method for constrained ordination, relating external information (e.g., environmental variables) with ecological data, considering species abundance as dependant on sites. Ordination axes are restricted to be linear combinations of the environmental variables, based on the information of the most abundant species. This extension and its associated unconstrained ordination method are terms of a global model that permits an empirical evaluation of the impact that the environmental variables have on the community composition. Scores, contributions, qualities of representation, interpretation of dispersion graphs and an application to real vegetation data are presented.Peer Reviewe

    Saprolegnia diclina IIIA and S. parasitica employ different infection strategies when colonizing eggs of Atlantic salmon, Salmo salar L.

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    Acknowledgements The work has been funded by the European Commission through the EU Marie Curie ITN project SAPRO (238550) (MMS, AW). We would also like to acknowledge support from the BBSRC and the University of Aberdeen (PvW) and Landcatch and AquaGen for providing salmon eggs. Elin Rolen's assistance with sequencing of the strains is highly appreciated.Peer reviewedPublisher PD

    Фактори, які кондиціонують поліваріантність ефектів бальнеотерапевтичного комплексу курорту Трускавець на інтракардіальну та центральну гемодинаміку

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    Показано что, разнообразие эффектов курса бальнеотерапии на курорте Трускавець на гемодинамику может быть сведено методом кластерного анализа к четырем вариантам. Методом дискриминантного анализа выявлены 15 исходных параметров гемодинамики, вегетативной регуляции и обмена электролитов и липидов, закономерно обуславливающих тот или иной вариант бальнеоэффекта.The method of an echocardiography studies reactings intracardial and central hemodynamics of the man on a course balneotherapy on a spa Truskavets'. Outgoing from shifts of main parameters: an index of contractility (IC), frequency of a rhythm (FR), middledynamic pressure (Pm), general peripheral resistance of vessels (GPRV), expulsion time (ET), enddyastolic (EDV), shock (SV) volumes of heart and cardiac output (CО) - is selected 4 types of reacting. Hypotensive bradycardiо-antikinetic reacting registered for 34,8% of persons, is characterized reduce of Pm, rhythm, ET and CО associated with absence of changes SV, EDV, GPRV and IC. For antiresistive tachycardiо-prokinetic type (30,3% of cases) is characteristic combination of increase of a FR, ET and CО with a considerable decrease GPRV. At proresistive antiinotropic tachycardiо-antikinetic type (19,7% of faces) is essentially increased GPRV and FR, reduced IC, ET, EDV, SV and CО. For 15,2% of faces is established antiresistive proinotropic prokinetic type described by a increase of IC, EDV, SV, FR and CО and decrease of GPRV. The type of effects are conditionized by constellation of 15 initial parameters of haemodynamic, vegetative regulation and exchange of lipides and electrolytes and are prognozed by method of disccriminant analysis (correctly 83,3%)

    Canonical non-symmetrical correspondence analysis: an alternative in constrained ordination

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    Canonical non-symmetrical correspondence analysis is developed as an alternative method for constrained ordination, relating external information (e.g., environmental variables) with ecological data, considering species abundance as dependant on sites. Ordination axes are restricted to be linear combinations of the environmental variables, based on the information of the most abundant species. This extension and its associated unconstrained ordination method are terms of a global model that permits an empirical evaluation of the impact that the environmental variables have on the community composition. Scores, contributions, qualities of representation, interpretation of dispersion graphs and an application to real vegetation data are presented.Peer Reviewe

    Assessment of climate change impact on hydrological extremes in two source regions of the Nile River Basin

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    The potential impact of climate change was investigated on the hydrological extremes of Nyando River and Lake Tana catchments, which are located in two source regions of the Nile River basin. Climate change scenarios were developed for rainfall and potential evapotranspiration (ETo), considering 17 General Circulation Model (GCM) simulations to better understand the range of possible future change. They were constructed by transferring the extracted climate change signals to the observed series using a frequency perturbation downscaling approach, which accounts for the changes in rainfall extremes. Projected changes under two future SRES emission scenarios A1B and B1 for the 2050s were considered. Two conceptual hydrological models were calibrated and used for the impact assessment. Their difference in simulating the flows under future climate scenarios was also investigated. <br><br> The results reveal increasing mean runoff and extreme peak flows for Nyando catchment for the 2050s while unclear trend is observed for Lake Tana catchment for mean volumes and high/low flows. The hydrological models for Lake Tana catchment, however, performed better in simulating the hydrological regimes than for Nyando, which obviously also induces a difference in the reliability of the extreme future projections for both catchments. The unclear impact result for Lake Tana catchment implies that the GCM uncertainty is more important for explaining the unclear trend than the hydrological models uncertainty. Nevertheless, to have a better understanding of future impact, hydrological models need to be verified for their credibility of simulating extreme flows

    On the reactivity of sleep monitoring with diaries

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    The declining costs of wearable sensors have made self-monitoring of sleep related behavior easier for personal use but also for sleep studies. Several monitor devices come with apps that make use of diary entries to provide people with an overview of their sleeping habits and give remotely advice. However, it could be that filling in a sleep diary impacts people's perception of their sleep or the very behavior that is being measured. A small-scale field study about the effects of sleep monitoring (keeping a sleep diary) on a cognitive and a behavioral level is discussed. The method was designed to be as open as possible in order to focus on the effects of sleep monitoring where participants are not given a goal, motivation or feedback. Some behavioral modifications were observed, for example, differences in total sleep time and bedtimes were found (compared to a non-monitoring week and a monitoring week). Nevertheless, what the causes are of these changes remains unclear, as it turned out that the two actigraph devices used in this study differed greatly. In addition, some participants became more aware of their sleeping routine, but changing a sleeping habit was found challenging because of other priorities. It is important to know what the effects may be of sleep monitoring as the outcomes may already have an effect on the participant behavior which could cause researchers to work with data that do not represent a real life situation. In addition, the self-monitoring may serve as an intervention for facilitating healthier sleeping habits.</p

    Real-time detection of single electron tunneling using a quantum point contact

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    We observe individual tunnel events of a single electron between a quantum dot and a reservoir, using a nearby quantum point contact (QPC) as a charge meter. The QPC is capacitively coupled to the dot, and the QPC conductance changes by about 1% if the number of electrons on the dot changes by one. The QPC is voltage biased and the current is monitored with an IV-convertor at room temperature. We can resolve tunnel events separated by only 8 μ\mus, limited by noise from the IV-convertor. Shot noise in the QPC sets a 25 ns lower bound on the accessible timescales.Comment: 3 pages, 3 figures, submitte
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