815 research outputs found
Overwash hazard assessment
Overwash is a natural storm-related process that occurs when wave runup overcomes the dune crest. Because coastlines are globally occupied, overwash is a hazardous process and there is a need to identify vulnerable areas. This study proposes a method to detect overwash-prone areas in the AncĂŁo peninsula, Portugal, and eventually outlines a vulnerability map. Dune base (DLOW) and crest (DHIGH) topography were surveyed. Three different storm scenarios (5-, 10- and 25- year return period storms) and associated waves and sea level were determined. According to these data, extreme wave runup (RHIGH) was calculated by a parameterisation set for intermediate-reflective beaches. The maps for collision and overwash regimes were designed by comparing RHIGH values with DLOW and DHIGH. Almost the entire dune base along the peninsula is vulnerable to collision regime. The overwash process was identified mainly along the tidal inlet hazard area and within the human-occupied portion of the beach, where overwash is expected to occur within 5 years of return period. The developed method considers the main overwash driving forces and proved to identify hazardous areas previously observed in the area. Occasional differences between modelled and observed overwash areas can be attributable to equipment errors, morphology interpretation subjectivity and maladjustments in runup parameterisation. Nevertheless, the method proved to be effective in reproducing the overall AncĂŁo peninsula vulnerability and can be widely applied. Therefore, it is a simple and potentially important tool for coastal management that enables mitigation strategies for occupied coasts and assessment of geological and ecological consequences in natural areas
Linear and non-linear perturbations in dark energy models
I review the linear and second-order perturbation theory in dark energy
models with explicit interaction to matter in view of applications to N-body
simulations and non-linear phenomena. Several new or generalized results are
obtained: the general equations for the linear perturbation growth; an
analytical expression for the bias induced by a species-dependent interaction;
the Yukawa correction to the gravitational potential due to dark energy
interaction; the second-order perturbation equations in coupled dark energy and
their Newtonian limit. I also show that a density-dependent effective dark
energy mass arises if the dark energy coupling is varying.Comment: 12 pages, submitted to Phys. Rev; v2: added a ref. and corrected a
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A FABP4-PPARÎł signaling axis regulates human monocyte responses to electrophilic fatty acid nitroalkenes
Nitro-fatty acids (NO2-FA) are electrophilic lipid mediators derived from unsaturated fatty acid nitration. These species are produced endogenously by metabolic and inflammatory reactions and mediate anti-oxidative and anti-inflammatory responses. NO2-FA have been postulated as partial agonists of the Peroxisome Proliferator-Activated Receptor gamma (PPARÎł), which is predominantly expressed in adipocytes and myeloid cells. Herein, we explored molecular and cellular events associated with PPARÎł activation by NO2-FA in monocytes and macrophages. NO2-FA induced the expression of two PPARÎł reporter genes, Fatty Acid Binding Protein 4 (FABP4) and the scavenger receptor CD36, at early stages of monocyte differentiation into macrophages. These responses were inhibited by the specific PPARÎł inhibitor GW9662. Attenuated NO2-FA effects on PPARÎł signaling were observed once cells were differentiated into macrophages, with a significant but lower FABP4 upregulation, and no induction of CD36. Using in vitro and in silico approaches, we demonstrated that NO2-FA bind to FABP4. Furthermore, the inhibition of monocyte FA binding by FABP4 diminished NO2-FA-induced upregulation of reporter genes that are transcriptionally regulated by PPARÎł, Keap1/Nrf2 and HSF1, indicating that FABP4 inhibition mitigates NO2-FA signaling actions. Overall, our results affirm that NO2-FA activate PPARÎł in monocytes and upregulate FABP4 expression, thus promoting a positive amplification loop for the downstream signaling actions of this mediator.Fil: Lamas Bervejillo, M.. Universidad de la RepĂșblica; UruguayFil: Bonanata, Julieta. Universidad de la RepĂșblica; UruguayFil: Franchini, Gisela Raquel. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de Investigaciones BioquĂmicas de La Plata "Prof. Dr. Rodolfo R. Brenner". Universidad Nacional de la Plata. Facultad de Ciencias MĂ©dicas. Instituto de Investigaciones BioquĂmicas de La Plata "Prof. Dr. Rodolfo R. Brenner"; ArgentinaFil: Richeri, A.. Instituto de Investigaciones BiolĂłgicas "Clemente Estable"; UruguayFil: MarquĂ©s, J.M.. Universidad de la RepĂșblica; UruguayFil: Freeman, B.A.. University of Pittsburgh; Estados UnidosFil: Schopfer, Francisco Jose. University of Pittsburgh; Estados UnidosFil: Coitiño, E.L.. Universidad de la RepĂșblica; UruguayFil: CĂłrsico, Betina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de Investigaciones BioquĂmicas de La Plata "Prof. Dr. Rodolfo R. Brenner". Universidad Nacional de la Plata. Facultad de Ciencias MĂ©dicas. Instituto de Investigaciones BioquĂmicas de La Plata "Prof. Dr. Rodolfo R. Brenner"; ArgentinaFil: Rubbo, H.. Universidad de la RepĂșblica; UruguayFil: Ferreira, A.M.. Universidad de la RepĂșblica; Urugua
Learning from the public: citizens describe the need to improve end-of-life care access, provision and recognition across Europe
Optimization of tetrazolium tests to assess the quality of Platymiscium floribundum , Lonchocarpus muehlbergianus and Acacia polyphylla DC. Seeds
A VP3/VP1 gene polymerase chain reaction assay for detection of chicken anemia virus in broiler samples
Softening the Supersymmetric Flavor Problem in Orbifold GUTs
The infra-red attractive force of the bulk gauge interactions is applied to
soften the supersymmetric flavor problem in the orbifold SU(5) GUT of Kawamura.
Then this force aligns in the infra-red regime the soft supersymmetry breaking
terms out of their anarchical disorder at a fundamental scale, in such a way
that flavor-changing neutral currents as well as dangerous CP-violating phases
are suppressed at low energies. It is found that this dynamical alignment is
sufficiently good compared with the current experimental bounds, as long as the
diagonalization matrices of the Yukawa couplings are CKM-like.Comment: 15 pages,4 figure
Perturbations in cosmologies with a scalar field and a perfect fluid
We study the properties of cosmological density perturbations in a
multi-component system consisting of a scalar field and a perfect fluid. We
discuss the number of degrees of freedom completely describing the system,
introduce a full set of dynamical gauge-invariant equations in terms of the
curvature and entropy perturbations, and display an efficient formulation of
these equations as a first-order system linked by a fairly sparse matrix. Our
formalism includes spatial gradients, extending previous formulations
restricted to the large-scale limit, and fully accounts for the evolution of an
isocurvature mode intrinsic to the scalar field. We then address the issue of
the adiabatic condition, in particular demonstrating its preservation on large
scales. Finally, we apply our formalism to the quintessence scenario and
clearly underline the importance of initial conditions when considering
late-time perturbations. In particular, we show that entropy perturbations can
still be present when the quintessence field energy density becomes
non-negligible.Comment: RevTex4, 9 pages, 3 figures. Significant additions on the
quintessence scenario (new appendix and additional numerical example).
Conclusions unchanged, but more robus
Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in âs = 7 TeV pp collisions with the ATLAS detector
A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fbâ1 of protonâproton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results
Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC
Measurements of inclusive jet suppression in heavy ion collisions at the LHC
provide direct sensitivity to the physics of jet quenching. In a sample of
lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated
luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with
a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the
transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the
anti-kt algorithm with values for the distance parameter that determines the
nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of
the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp.
Jet production is found to be suppressed by approximately a factor of two in
the 10% most central collisions relative to peripheral collisions. Rcp varies
smoothly with centrality as characterized by the number of participating
nucleons. The observed suppression is only weakly dependent on jet radius and
transverse momentum. These results provide the first direct measurement of
inclusive jet suppression in heavy ion collisions and complement previous
measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables,
submitted to Physics Letters B. All figures including auxiliary figures are
available at
http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02
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