2,085 research outputs found

    Planothidum audax sp. nov. (Bacillariophyta, Achnanthidiaceae), a new diatom from temporary streams in southern Portugal

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    emporary streams represent ca. half of the river network at the worldwide level, and in regions such as southern Europe their dominance of the landscape is evident (Larned et al. 2010, McDonough et al. 2011, Barbosa et al. 2020). Currently, these streams are receiving increased attention due to their importance as high diversity spots for algae, arthropods, plants, etc., and due to the ecosystem services they provide (Acuña et al. 2014, Datry et al. 2018b). Because of their geographical position and the land use changes in their watersheds (increased urbanization, agriculture, etc.), climate change, contamination and habitat fragmentation constitute forces threatening their integrity and ecological characteristics (Datry et al. 2018a, Bonada et al. 2020)

    Rotating Black Branes in the presence of nonlinear electromagnetic field

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    In this paper, we consider a class of gravity whose action represents itself as a sum of the usual Einstein-Hilbert action with cosmological constant and an U(1)U(1) gauge field for which the action is given by a power of the Maxwell invariant. We present a class of the rotating black branes with Ricci flat horizon and show that the presented solutions may be interpreted as black brane solutions with two event horizons, extreme black hole and naked singularity provided the parameters of the solutions are chosen suitably. We investigate the properties of the solutions and find that for the special values of the nonlinear parameter, the solutions are not asymptotically anti-deSitter. At last, we obtain the conserved quantities of the rotating black branes and find that the nonlinear source effects on the electric field, the behavior of spacetime, type of singularity and other quantities.Comment: 7 pages, 5 figures, to appear in EPJ

    The SARS-CoV-2 Pandemic Impacts the Management of Swiss Pediatric Intensive Care Units.

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    The impact of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) pandemic on pediatric intensive care units (PICUs) is difficult to quantify. We conducted an observational study in all eight Swiss PICUs between 02/24/2020 and 06/15/2020 to characterize the logistical and medical aspects of the pandemic and their impact on the management of the Swiss PICUs. The nine patients admitted to Swiss PICUs during the study period suffering from pediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 (PIMS-TS) and constituting 14% (9/63) of all SARS-CoV-2 positive hospitalized patients in Swiss children's hospitals caused a higher workload [total Nine Equivalents of nursing Manpower use Score (NEMS) points, p = 0.0008] and were classified to higher workload categories (p < 0.0001) than regular PICU patients (n = 4,881) admitted in 2019. The comparison of the characteristics of the eight Swiss PICUs shows that they were confronted by different organizational issues arising from temporary regulations put in place by the federal council. These general regulations had different consequences for the eight individual PICUs due to the differences between the PICUs. In addition, the temporal relationship of these different regulations influenced the available PICU resources, dependent on the characteristics of the individual PICUs. As pandemic continues, reflecting and learning from experience is essential to reduce workload, optimize bed occupancy and manage resources in each individual PICU. In a small country as Switzerland, with a relatively decentralized health care local differences between PICUs are considerable and should be taken into account when making policy decisions

    Specifying and Analysing SOC Applications with COWS

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    COWS is a recently defined process calculus for specifying and combining service-oriented applications, while modelling their dynamic behaviour. Since its introduction, a number of methods and tools have been devised to analyse COWS specifications, like e.g. a type system to check confidentiality properties, a logic and a model checker to express and check functional properties of services. In this paper, by means of a case study in the area of automotive systems, we demonstrate that COWS, with some mild linguistic additions, can model all the phases of the life cycle of service-oriented applications, such as publication, discovery, negotiation, orchestration, deployment, reconfiguration and execution. We also provide a flavour of the properties that can be analysed by using the tools mentioned above

    Three-Neutrino Mixing after the First Results from K2K and KamLAND

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    We analyze the impact of the data on long baseline \nu_\mu disappearance from the K2K experiment and reactor \bar\nu_e disappearance from the KamLAND experiment on the determination of the leptonic three-generation mixing parameters. Performing an up-to-date global analysis of solar, atmospheric, reactor and long baseline neutrino data in the context of three-neutrino oscillations, we determine the presently allowed ranges of masses and mixing and we consistently derive the allowed magnitude of the elements of the leptonic mixing matrix. We also quantify the maximum allowed contribution of \Delta m^2_{21} oscillations to CP-odd and CP-even observables at future long baseline experiments.Comment: Some typos correcte

    Growth, competition and cooperation in spatial population genetics

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    We study an individual based model describing competition in space between two different alleles. Although the model is similar in spirit to classic models of spatial population genetics such as the stepping stone model, here however space is continuous and the total density of competing individuals fluctuates due to demographic stochasticity. By means of analytics and numerical simulations, we study the behavior of fixation probabilities, fixation times, and heterozygosity, in a neutral setting and in cases where the two species can compete or cooperate. By concluding with examples in which individuals are transported by fluid flows, we argue that this model is a natural choice to describe competition in marine environments.Comment: 29 pages, 14 figures; revised version including a section with results in the presence of fluid flow

    Atmospheric Neutrino Oscillations and New Physics

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    We study the robustness of the determination of the neutrino masses and mixing from the analysis of atmospheric and K2K data under the presence of different forms of phenomenologically allowed new physics in the nu_mu--nu_tau sector. We focus on vector and tensor-like new physics interactions which allow us to treat, in a model independent way, effects due to the violation of the equivalence principle, violations of the Lorentz invariance both CPT conserving and CPT violating, non-universal couplings to a torsion field and non-standard neutrino interactions with matter. We perform a global analysis of the full atmospheric data from SKI together with long baseline K2K data in the presence of nu_mu -> nu_tau transitions driven by neutrino masses and mixing together with sub-dominant effects due to these forms of new physics. We show that within the present degree of experimental precision, the extracted values of masses and mixing are robust under those effects and we derive the upper bounds on the possible strength of these new interactions in the nu_mu--nu_tau sector.Comment: 22 pages, LaTeX file using RevTEX4, 5 figures and 4 tables include

    Monolayer-functionalized microfluidics devices for optical sensing of acidity

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    This paper describes the integration of opto-chemosensors in microfluidics networks. Our technique exploits the internal surface of the network as a platform to build a sensing system by coating the surface with a self-assembled monolayer and subsequently binding a fluorescent sensing molecule to the monolayer. Fluorescent molecules were used that can switch between a fluorescent and a non-fluorescent state, depending on the acidity of the surrounding solution. Two systems were investigated. The first employs surface confinement of a Rhodamine B dye in a glass micro channel that serves as a molecular switch in organic solutions. Upon rinsing the micro channels with acidic or basic solutions it was possible to switch between the fluorescent and non- fluorescent forms reversibly. Moreover, this system could be used to monitor the mixing of two solutions of different acidity along the micro channel. To widen the scope of optical sensing in micro channels an Oregon Green dye derivative was immobilized, which functions as a sensing molecule for pH differences in aqueous solutions. In this case, a hybrid system was used consisting of a glass slide and PDMS channels. The fluorescence intensity was found to be directly correlated to the pH of the solution in contact, indicating the possibility of using such a system as a pH sensor. These systems allow real-time measurements and can be easily implemented in micro- and nanofluidics systems thus enabling analysis of extremely small sample volumes in a fast and reproducible manner

    Dynamics of a classical gas including dissipative and mean field effects

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    By means of a scaling ansatz, we investigate an approximated solution of the Boltzmann-Vlasov equation for a classical gas. Within this framework, we derive the frequencies and the damping of the collective oscillations of a harmonically trapped gas and we investigate its expansion after release of the trap. The method is well suited to studying the collisional effects taking place in the system and in particular to discussing the crossover between the hydrodynamic and the collisionless regimes. An explicit link between the relaxation times relevant for the damping of the collective oscillations and for the expansion is established.Comment: 4 pages, 1 figur

    Vortex phase diagram in trapped Bose-Einstein condensation

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    The vortex phase diagram in the external rotation frequency versus temperature is calculated for dilute Bose-Einstein condensed gases. It is determined within the Bogoliubov-Popov theory for a finite temperature where the condensate and non-condensate fractions are treated in an equal footing. The temperature dependences of various thermodynamic instability lines for the vortex nucleation are computed to construct the phase diagram. Experiments are proposed to resolve a recent controversy on the vortex creation problem associated with the quantized vortex observation in 87^{87}Rb atom gases.Comment: 11 pages, 8 figure
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