3,144 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

    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

    Weak gravitational lensing with the Square Kilometre Array

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    We investigate the capabilities of various stages of the SKA to perform world-leading weak gravitational lensing surveys. We outline a way forward to develop the tools needed for pursuing weak lensing in the radio band. We identify the key analysis challenges and the key pathfinder experiments that will allow us to address them in the run up to the SKA. We identify and summarize the unique and potentially very powerful aspects of radio weak lensing surveys, facilitated by the SKA, that can solve major challenges in the field of weak lensing. These include the use of polarization and rotational velocity information to control intrinsic alignments, and the new area of weak lensing using intensity mapping experiments. We show how the SKA lensing surveys will both complement and enhance corresponding efforts in the optical wavebands through cross-correlation techniques and by way of extending the reach of weak lensing to high redshift.Comment: 19 pages, 6 figures. Cosmology Chapter, Advancing Astrophysics with the SKA (AASKA14) Conference, Giardini Naxos (Italy), June 9th-13th 201

    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

    Giant-dipole Resonance and the Deformation of Hot, Rotating Nuclei

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    The development of nuclear shapes under the extreme conditions of high spin and/or temperature is examined. Scaling properties are used to demonstrate universal properties of both thermal expectation values of nuclear shapes as well as the minima of the free energy, which can be used to understand the Jacobi transition. A universal correlation between the width of the giant dipole resonance and quadrupole deformation is found, providing a novel probe to measure the nuclear deformation in hot nuclei.Comment: 6 pages including 6 figures. To appear in Phys. Rev. Lett. Revtex

    A parametrization of the growth index of matter perturbations in various Dark Energy models and observational prospects using a Euclid-like survey

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    We provide exact solutions to the cosmological matter perturbation equation in a homogeneous FLRW universe with a vacuum energy that can be parametrized by a constant equation of state parameter ww and a very accurate approximation for the Ansatz w(a)=w0+wa(1a)w(a)=w_0+w_a(1-a). We compute the growth index \gamma=\log f(a)/\log\Om_m(a), and its redshift dependence, using the exact and approximate solutions in terms of Legendre polynomials and show that it can be parametrized as γ(a)=γ0+γa(1a)\gamma(a)=\gamma_0+\gamma_a(1-a) in most cases. We then compare four different types of dark energy (DE) models: wΛw\LambdaCDM, DGP, f(R)f(R) and a LTB-large-void model, which have very different behaviors at z\gsim1. This allows us to study the possibility to differentiate between different DE alternatives using wide and deep surveys like Euclid, which will measure both photometric and spectroscopic redshifts for several hundreds of millions of galaxies up to redshift z2z\simeq 2. We do a Fisher matrix analysis for the prospects of differentiating among the different DE models in terms of the growth index, taken as a given function of redshift or with a principal component analysis, with a value for each redshift bin for a Euclid-like survey. We use as observables the complete and marginalized power spectrum of galaxies P(k)P(k) and the Weak Lensing (WL) power spectrum. We find that, using P(k)P(k), one can reach (2%, 5%) errors in (w0,wa)(w_0, w_a), and (4%, 12%) errors in (γ0,γa)(\gamma_0, \gamma_a), while using WL we get errors at least twice as large. These estimates allow us to differentiate easily between DGP, f(R)f(R) models and Λ\LambdaCDM, while it would be more difficult to distinguish the latter from a variable equation of state parameter or LTB models using only the growth index.}Comment: 29 pages, 7 figures, 6 table

    Identification and rejection of scattered neutrons in AGATA

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    Gamma rays and neutrons, emitted following spontaneous fission of 252Cf, were measured in an AGATA experiment performed at INFN Laboratori Nazionali di Legnaro in Italy. The setup consisted of four AGATA triple cluster detectors (12 36-fold segmented high-purity germanium crystals), placed at a distance of 50 cm from the source, and 16 HELENA BaF2 detectors. The aim of the experiment was to study the interaction of neutrons in the segmented high-purity germanium detectors of AGATA and to investigate the possibility to discriminate neutrons and gamma rays with the gamma-ray tracking technique. The BaF2 detectors were used for a time-of-flight measurement, which gave an independent discrimination of neutrons and gamma rays and which was used to optimise the gamma-ray tracking-based neutron rejection methods. It was found that standard gamma-ray tracking, without any additional neutron rejection features, eliminates effectively most of the interaction points due to recoiling Ge nuclei after elastic scattering of neutrons. Standard tracking rejects also a significant amount of the events due to inelastic scattering of neutrons in the germanium crystals. Further enhancements of the neutron rejection was obtained by setting conditions on the following quantities, which were evaluated for each event by the tracking algorithm: energy of the first and second interaction point, difference in the calculated incoming direction of the gamma ray, figure-of-merit value. The experimental results of tracking with neutron rejection agree rather well with Geant4 simulations

    Inoculação de Curtobacterium flaccumfaciens pv. flaccumfaciens em sementes de feijão por meio da técnica de condicionamento fisiológico.

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    Neste estudo foi testada a técnica de condicionamento fisiológico em meio agarizado para inoculação de Curtobacterium flaccumfaciens pv. flaccumfaciens (Cff) em sementes de feijão. Na primeira etapa, avaliou-se o comportamento das sementes de feijão cultivar Pérola, durante o pré-condicionamento osmótico em substrato agarizado com restrição hídrica. Os tratamentos consistiram em expor, por diferentes períodos de tempo, sementes de feijão desinfestadas a quatro níveis de restrição hídrica do meio 523 (-0,55, -0,75, -0,95 e -1,15 MPa), com o uso de quatro substratos (meio 523, meio 523+KCl, meio 523+manitol e meio 523+sacarose). Como testemunha, utilizou-se o meio 523 sem restrição hídrica (-0,55 MPa). Decorridos os respectivos tempos, avaliou-se a percentagem de sementes com protrusão radicular e, posteriormente, o teor de água, a germinação e os padrões enzimáticos das sementes. Na segunda etapa do estudo, avaliou-se o crescimento de quatro isolados de Cff (Cff DF - Feij-2936, Cff PR - 12768, Cff SC - Feij-2928 e Cff SP - Feij-2634) em substrato agarizado com restrição hídrica. Os tratamentos da terceira etapa foram definidos com base na primeira etapa, em que o melhor tratamento foi o meio 523 com manitol no potencial hídrico de -0,95 MPa e com 48 horas de exposição das sementes no meio agarizado. Na segunda etapa, verificou-se que o isolado de Cff SC (Feij-2928), proveniente do estado de Santa Catarina, apresentou o melhor crescimento no substrato e no potencial hídrico definido na primeira etapa. Portanto, foi possível a inoculação artificial de sementes de feijão com Cff por meio da técnica de condicionamento fisiológico em substrato agarizado, sem o comprometimento de sua qualidade fisiológica

    Weak lensing peak count as a probe of f(R) theories

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    Weak gravitational lensing by galaxy clusters on faint higher redshift galaxies has been traditionally used to study the cluster mass distribution and as a tool to identify clusters as peaks in the shear maps. However, it becomes soon clear that peaks statistics can also be used as a way to constrain the underlying cosmological model due to its dependence on both the cosmic expansion rate and the growth rate of structures. This feature makes peak statistics particularly interesting from the point of view of discriminating between General Relativity and modified gravity. Here we consider a general class of f(R)f(R) theories and compute the observable mass function based on the aperture mass statistics. We complement our theoretical analysis with a Fisher matrix forecast of the constraints that an Euclid\,-\,like survey can impose on the f(R)f(R) model parameters. We show that peak statistics alone can in principle discriminate between General Relativity and f(R)f(R) models and strongly constrain the f(R)f(R) parameters that are sensitive to the non-linear growth of structure. However, further analysis is needed in order to include possible selection function in the peaks redshift determination.Comment: 17 pages, 9 figures, 1 table, accepted for publication on MNRAS on Jan 14, 2013; updated to match the published versio
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