2,028 research outputs found

    Mass - concentration relation and weak lensing peak counts

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    The statistics of peaks in weak lensing convergence maps is a promising tool to investigate both the properties of dark matter haloes and constrain the cosmological parameters. We study how the number of detectable peaks and its scaling with redshift depend upon the cluster dark matter halo profiles and use peak statistics to constrain the parameters of the mass - concentration (MC) relation. We investigate which constraints the Euclid mission can set on the MC coefficients also taking into account degeneracies with the cosmological parameters. To this end, we first estimate the number of peaks and its redshift distribution for different MC relations. We find that the steeper the mass dependence and the larger the normalisation, the higher is the number of detectable clusters, with the total number of peaks changing up to 40%40\% depending on the MC relation. We then perform a Fisher matrix forecast of the errors on the MC relation parameters as well as cosmological parameters. We find that peak number counts detected by Euclid can determine the normalization AvA_v, the mass BvB_v and redshift CvC_v slopes and intrinsic scatter σv\sigma_v of the MC relation to an unprecedented accuracy being σ(Av)/Av=1%\sigma(A_v)/A_v = 1\%, σ(Bv)/Bv=4%\sigma(B_v)/B_v = 4\%, σ(Cv)/Cv=9%\sigma(C_v)/C_v = 9\%, σ(σv)/σv=1%\sigma(\sigma_v)/\sigma_v = 1\% if all cosmological parameters are assumed to be known. Should we relax this severe assumption, constraints are degraded, but remarkably good results can be restored setting only some of the parameters or combining peak counts with Planck data. This precision can give insight on competing scenarios of structure formation and evolution and on the role of baryons in cluster assembling. Alternatively, for a fixed MC relation, future peaks counts can perform as well as current BAO and SNeIa when combined with Planck.Comment: 14 pages, 8 figures, accepted for publication on Astronomy & Astrophysic

    Network Analysis, Creative System Modelling and Decision Support: The NetSyMoD Approach

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    This paper presents the NetSyMoD approach – where NetSyMod stands for Network Analysis – Creative System Modelling – Decision Support. It represents the outcome of several years of research at FEEM in the field of natural resources management, environmental evaluation and decision-making, within the Natural Resources Management Research Programme. NetSyMoD is a flexible and comprehensive methodological framework, which uses a suite of support tools, aimed at facilitating the involvement of stakeholders or experts in decision-making processes. The main phases envisaged for the process are: (i) the identification of relevant actors, (ii) the analysis of social networks, (iii) the creative system modelling and modelling of the reality being considered (i.e. the local socio-economic and environmental system), and (iv) the analysis of alternative options available for the management of the specific case (e.g. alternative projects, plans, strategies). The strategies for participation are necessarily context-dependent, and thus not all the NetSyMod phases may be needed in every application. Furthermore, the practical solutions for their implementation may significantly differ from one case to another, depending not only on the context, but also on the available resources (human and financial). The various applications of NetSyMoD have nonetheless in common the same approach for problem analysis and communication within a group of actors, based upon the use of creative thinking techniques, the formalisation of human-environment relationships through the DPSIR framework, and the use of multi-criteria analysis through the mDSS software.Social Network, Integrated Analysis, Participatory Modelling, Decision Support

    Jack of All Trades or Master of One? Specialization, Trade and Money

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    We consider a model of decentralized exchange where individuals choose the set of goods they produce. Specialization involves producing a smaller set of goods and doing it more proÞciently. In doing so, agents reduce production costs, but also reduce the ease of trading their output. We derive the equilibrium degree of specialization and examine how it is affected by underlying fundamentals. Due to the existence of a hold-up problem, individuals specialize too little relative to the social optimum. Introducing money leads to more specialization relative to barter and increases welfare

    Jack of All Trades or Master of One? Specialization, Trade and Money

    Get PDF
    We consider a model of decentralized exchange where individuals choose the set of goods they produce. Specialization involves producing a smaller set of goods and doing it more proÞciently. In doing so, agents reduce production costs, but also reduce the ease of trading their output. We derive the equilibrium degree of specialization and examine how it is affected by underlying fundamentals. Due to the existence of a hold-up problem, individuals specialize too little relative to the social optimum. Introducing money leads to more specialization relative to barter and increases welfare

    Honing cross-correlation tools for inference on ultra-high-energy cosmic-ray composition

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    The chemical composition of the highest-energy cosmic rays, namely the atomic number ZZ of rays with energies E1 EeVE\gg1~\text{EeV}, remains to date largely unknown. Some information on the composition can be inferred from the deflections that charged ultra-high-energy cosmic rays experience while they traverse intervening magnetic fields. Indeed, such deflections distort and suppress the original anisotropy in the cosmic rays arrival directions; thus, a measure of the anisotropy is also a measurement of the deflections, which in turn informs us on the chemical composition. In this work, we show that, by quantifying ultra-high-energy cosmic ray anisotropies through the angular, harmonic cross-correlation between cosmic rays and galaxies, we are able to exclude iron fractions fFeO(10%)f_{\rm Fe}\leq{\cal O}(10\%) on a fiducial hydrogen map at 2σ2\sigma level, and even smaller fractions in the reverse case of hydrogen on an iron map, going below fH10%f_{\rm H}\lesssim10\% when we mask the Galactic Centre up to latitudes of 40deg40\,\text{deg}. This is an improvement of a factor of a few compared to our previous method, and is mostly ascribable to a new test statistics which is sensitive to each harmonic multipole individually. Our method can be applied to real data as an independent test of the recent claim that current cosmic-ray data can not be reproduced by any existing model of the Galactic magnetic field, as well as an additional handle to compare any realistic, competing, data-driven composition models.Comment: 9 pages, 3 figures + appendix. To be submitte

    Intravenous itraconazole for treating invasive pulmonary aspergillosis in neutropenic patients with acute lymphoblastic leukemia.

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    Aspergillus infection is associated with a high mortality rate in immunocompromised hosts; more effective drugs for this infection are needed. Oral itraconazole has been studied in neutropenic fungus-infected patients. Using a novel formulation (intravenous) of itraconazole, we successfully treated severe necrotizing pneumonias due to Aspergillus species occurring during a postchemotherapy prolonged aplastic phase in two patients with acute lymphoblastic leukemia

    Nonlinear diffusion & thermo-electric coupling in a two-variable model of cardiac action potential

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    This work reports the results of the theoretical investigation of nonlinear dynamics and spiral wave breakup in a generalized two-variable model of cardiac action potential accounting for thermo-electric coupling and diffusion nonlinearities. As customary in excitable media, the common Q10 and Moore factors are used to describe thermo-electric feedback in a 10-degrees range. Motivated by the porous nature of the cardiac tissue, in this study we also propose a nonlinear Fickian flux formulated by Taylor expanding the voltage dependent diffusion coefficient up to quadratic terms. A fine tuning of the diffusive parameters is performed a priori to match the conduction velocity of the equivalent cable model. The resulting combined effects are then studied by numerically simulating different stimulation protocols on a one-dimensional cable. Model features are compared in terms of action potential morphology, restitution curves, frequency spectra and spatio-temporal phase differences. Two-dimensional long-run simulations are finally performed to characterize spiral breakup during sustained fibrillation at different thermal states. Temperature and nonlinear diffusion effects are found to impact the repolarization phase of the action potential wave with non-monotone patterns and to increase the propensity of arrhythmogenesis

    Non-monotonic current-to-rate response function in a novel integrate-and-fire model neuron

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    A novel integrate-and-fire model neuron is proposed to account for a non-monotonic f-I response function, as experimentally observed. As opposed to classical forms of adaptation, the present integrate- and-fire model the spike-emission process incorporates a state - dependent inactivation that makes the probability of emitting a spike decreasing as a function of the mean depolarization level instead of the mean firing rate. \ua9 Springer-Verlag Berlin Heidelberg 2002

    Central venous catheter insertion: a bedside procedure for haematological patients.

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    The present management of onco-haematologic patients may require continuous infusion of cytotoxic drugs, use of drugs or concentrated ion solutions which are toxic for the endothelial wall of small vessels, infusion of large amounts of antibiotics or antimycotics, red blood cell and platelet transfusion, and not rarely parenteral nutrition. Such a complex therapy needs a vascular access by a central vein catheter (CVC) insertion. Many types of CVC are available at present: tunnelled Hickman or Hickmanlike catheters, subcutaneous ports, tunnelled catheters with Groshong valve, external untunnelled catheters
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