43 research outputs found

    Spherical Symmetric Solutions in Ho\v{r}ava-Lifshitz Gravity and their Properties

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    Non-projectable Ho\v{r}ava gravity for a spherically symmetric configuration with őĽ=1\lambda=1 exhibits an infinite set of solutions parametrized by a generic function g2(r)g^{2}(r) for the radial component of the shift vector. In the IR limit the infinite set of solutions corresponds to the invariance of General Relativity under a spacetime reparametrization. In general, not being a coordinate transformation, the symmetry in the action responsible for the infinite set of solutions does not have a clear physical interpretation. Indeed it is broken by the matter term in the action. We study the behavior of the solutions for generic values of the parameter g2(r)g^{2}(r).Comment: References adde

    Spin-density and Vorticity Contribution to the Cosmological Background

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    Relativistic non-Abelian spinning fluids can be formulated in group theory language, where the corresponding Mathisson-Papapetrou equation for spinning fluids can be obtained in terms of a specific de Sitter group contraction. This framework is very suitable for studying the effects of a spinning fluid of matter with vorticity and a spin density in a cosmological background

    General static spherically symmetric solutions in Horava gravity

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    We derive general static spherically symmetric solutions in the Horava theory of gravity with nonzero shift field. These represent "hedgehog" versions of black holes with radial "hair" arising from the shift field. For the case of the standard de Witt kinetic term (lambda =1) there is an infinity of solutions that exhibit a deformed version of reparametrization invariance away from the general relativistic limit. Special solutions also arise in the anisotropic conformal point lambda = 1/3.Comment: References adde

    HoŇôava Gravity: Symmetries and Generalized Particle Dynamics

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    In the search for a theory of Quantum Gravity a new proposal was recently made by P. HoŇôava. The main feature of this new proposed theory is that it is power-counting renormalizable by construction, and could prove to be truly renormalizable, although more work is needed in this direction. The renormalizability of the theory is a central issue. Indeed, General Relativity does not have this property, implying that to construct its quantum version we need to ‚Äúcomplete‚ÄĚ the theory in the UV. HoŇôava suggested a possible way to provide a UV completion of GR by giving up full spacetime reparametrization symmetry, which is one of the fundamental assumptions of GR, and adding appropriate higher order terms in the action. In this Thesis we review HoŇôava‚Äôs theory and analyze some of the issues related to the breaking of the spacetime structure. Specifically, we derive the general static spherically symmetric solutions for HoŇôava‚Äôs theory with a nonvanishing radial ‚Äúshift‚ÄĚ field gtr. Such ‚Äúhedgehog‚ÄĚ configurations are not considered in GR, since gtr can be mapped to zero with an appropriate reparametrization, but they are physically distinct solutions in HoŇôava gravity where the reparametrization is not allowed by the reduced symmetry. These new solutions exhibit specific properties from the particle dynamics point of view and possess an extra gauge symmetry. We also study the deformed kinematics of point particles allowed by the reduced reparametrization symmetry. The main result is that particles can have generalized dispersion relations that include higher even powers of the momentum. We analyze the implications of this and provide some examples that may be converted into possible experimental tests for the deviations of this new theory of gravity from standard GR

    Internet of Energy Training through Remote Laboratory Demonstrator

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    In this paper, a new learning tool is proposed to train professional figures, such as entrepreneurs, engineers, and technicians, who need to improve their skills in the field of Internet of Energy. The proposed tool aims to cover the lack of experimental knowledge on new energy systems and to layer proper skills, which are useful to deal with challenges required by smart energy management in the new complex distributed configuration of the electric power systems, characterized by demand response services. This tool is based on a small-scale laboratory demonstrator, representative of a smart rural house, equipped with a measurement and control system. This demonstrator can be remotely accessed, through web server applications based on a low cost single-board computer. Trainers can have direct experience on the main concepts related to smart grids, renewable energy sources, electrochemical storage systems, and electric vehicles, through the use of the proposed tool managed by the web software interface. Document type: Articl

    Expression of DAI by an oncolytic vaccinia virus boosts the immunogenicity of the virus and enhances antitumor immunity

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    In oncolytic virotherapy, the ability of the virus to activate the immune system is a key attribute with regard to long-term antitumor effects. Vaccinia viruses bear one of the strongest oncolytic activities among all oncolytic viruses. However, its capacity for stimulation of antitumor immunity is not optimal, mainly due to its immunosuppressive nature. To overcome this problem, we developed an oncolytic VV that expresses intracellular pattern recognition receptor DNA-dependent activator of IFN-regulatory factors (DAI) to boost the innate immune system and to activate adaptive immune cells in the tumor. We showed that infection with DAI-expressing VV increases expression of several genes related to important immunological pathways. Treatment with DAI-armed VV resulted in significant reduction in the size of syngeneic melanoma tumors in mice. When the mice were rechallenged with the same tumor, DAI-VV-treated mice completely rejected growth of the new tumor, which indicates immunity established against the tumor. We also showed enhanced control of growth of human melanoma tumors and elevated levels of human T-cells in DAI-VV-treated mice humanized with human peripheral blood mononuclear cells. We conclude that expression of DAI by an oncolytic VV is a promising way to amplify the vaccine potency of an oncolytic vaccinia virus to trigger the innate-and eventually the long-lasting adaptive immunity against cancer.Peer reviewe

    Reversible adhesion by type IV pili leads to formation of permanent localized clusters

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    The formation of long-lived, multicellular clusters is a fundamental step in the physiopathology of many disease-causing bacteria. Experiments on abiotic surfaces suggest that bacterial colonization, including initial cluster formation, requires (1) irreversible adhesion, (2) cell proliferation, and (3) a phenotypic transition. However, here we show that on infection of a polarized MDCK epithelium, Pseudomonas aeruginosa (PA) forms long-lived ‚Äď i.e., permanent ‚Äď bacterial clusters without requiring irreversible adhesion, cell proliferation, or a phenotypic transition. By combining experiments and a mathematical model, we reveal that the cluster formation process is mediated by type IV pili (T4P). Furthermore, we unveil how T4P quantitatively operate during adhesion, finding that it is a stochastic process that involves an activation time, requires the retraction of pili, and results in reversible attachment. We explain how such reversible attachment process leads to the formation of permanent bacterial clusters and quantify the cluster growth dynamics.Fil: Pepe, Mar√≠a Victoria. Consejo Nacional de Investigaciones Cient√≠ficas y T√©cnicas. Centro Cient√≠fico Tecnol√≥gico Conicet - La Plata. Instituto de Investigaciones Biotecnol√≥gicas. Universidad Nacional de San Mart√≠n. Instituto de Investigaciones Biotecnol√≥gicas; ArgentinaFil: Dea, Maria Celeste. Consejo Nacional de Investigaciones Cient√≠ficas y T√©cnicas. Centro Cient√≠fico Tecnol√≥gico Conicet - La Plata. Instituto de Investigaciones Biotecnol√≥gicas. Universidad Nacional de San Mart√≠n. Instituto de Investigaciones Biotecnol√≥gicas; ArgentinaFil: Genskowsky Vargas, Camila Alejandra. Consejo Nacional de Investigaciones Cient√≠ficas y T√©cnicas. Centro Cient√≠fico Tecnol√≥gico Conicet - La Plata. Instituto de Investigaciones Biotecnol√≥gicas. Universidad Nacional de San Mart√≠n. Instituto de Investigaciones Biotecnol√≥gicas; ArgentinaFil: Capasso, Dario Nicol√°s. Consejo Nacional de Investigaciones Cient√≠ficas y T√©cnicas. Centro Cient√≠fico Tecnol√≥gico Conicet - La Plata. Instituto de Investigaciones Biotecnol√≥gicas. Universidad Nacional de San Mart√≠n. Instituto de Investigaciones Biotecnol√≥gicas; ArgentinaFil: Roset, Mara Sabrina. Consejo Nacional de Investigaciones Cient√≠ficas y T√©cnicas. Centro Cient√≠fico Tecnol√≥gico Conicet - La Plata. Instituto de Investigaciones Biotecnol√≥gicas. Universidad Nacional de San Mart√≠n. Instituto de Investigaciones Biotecnol√≥gicas; ArgentinaFil: Jager, Adriana Valeria. Consejo Nacional de Investigaciones Cient√≠ficas y T√©cnicas. Centro Cient√≠fico Tecnol√≥gico Conicet - La Plata. Instituto de Investigaciones Biotecnol√≥gicas. Universidad Nacional de San Mart√≠n. Instituto de Investigaciones Biotecnol√≥gicas; ArgentinaFil: Peruani San Rom√°n, Fernando Miguel. Cergy-paris Universite (cergy-paris Universite); FranciaFil: Kierbel, Arlinet Ver√≥nica. Consejo Nacional de Investigaciones Cient√≠ficas y T√©cnicas. Centro Cient√≠fico Tecnol√≥gico Conicet - La Plata. Instituto de Investigaciones Biotecnol√≥gicas. Universidad Nacional de San Mart√≠n. Instituto de Investigaciones Biotecnol√≥gicas; Argentin

    mTOR-dependent translation amplifies microglia priming in aging mice.

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    peer reviewedMicroglia maintain homeostasis in the brain. However, with age, they become primed and respond more strongly to inflammatory stimuli. We show here that microglia from aged mice had upregulated mTOR complex 1 signaling controlling translation, as well as protein levels of inflammatory mediators. Genetic ablation of mTOR signaling showed a dual yet contrasting effect on microglia priming: it caused an NF-őļB-dependent upregulation of priming genes at the mRNA level; however, mice displayed reduced cytokine protein levels, diminished microglia activation, and milder sickness behavior. The effect on translation was dependent on reduced phosphorylation of 4EBP1, resulting in decreased binding of eIF4E to eIF4G. Similar changes were present in aged human microglia and in damage-associated microglia, indicating that upregulation of mTOR-dependent translation is an essential aspect of microglia priming in aging and neurodegeneration
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