303 research outputs found
Robustness of the European power grids under intentional attack
The power grid defines one of the most important technological networks of
our times and sustains our complex society. It has evolved for more than a
century into an extremely huge and seemingly robust and well understood system.
But it becomes extremely fragile as well, when unexpected, usually minimal,
failures turn into unknown dynamical behaviours leading, for example, to sudden
and massive blackouts. Here we explore the fragility of the European power grid
under the effect of selective node removal. A mean field analysis of fragility
against attacks is presented together with the observed patterns. Deviations
from the theoretical conditions for network percolation (and fragmentation)
under attacks are analysed and correlated with non topological reliability
measures.Comment: 7 pages, 4 figure
Multi-Player and Multi-Choice Quantum Game
We investigate a multi-player and multi-choice quantum game. We start from
two-player and two-choice game and the result is better than its classical
version. Then we extend it to N-player and N-choice cases. In the quantum
domain, we provide a strategy with which players can always avoid the worst
outcome. Also, by changing the value of the parameter of the initial state, the
probabilities for players to obtain the best payoff will be much higher that in
its classical version.Comment: 4 pages, 1 figur
Phonon Squeezed States Generated by Second Order Raman Scattering
We study squeezed states of phonons, which allow a reduction in the quantum
fluctuations of the atomic displacements to below the zero-point quantum noise
level of coherent phonon states. We investigate the generation of squeezed
phonon states using a second order Raman scattering process. We calculate the
expectation values and fluctuations of both the atomic displacement and the
lattice amplitude operators, as well as the effects of the phonon squeezed
states on macroscopically measurable quantities, such as changes in the
dielectric constant. These results are compared with recent experiments.Comment: 4 pages, REVTE
Spectroscopic evidence for a gold-coloured metallic water solution
Insulating materials can in principle be made metallic by applying pressure. In the case of pure water, this is estimated1 to require a pressure of 48 megabar, which is beyond current experimental capabilities and may only exist in the interior of large planets or stars2–4. Indeed, recent estimates and experiments indicate that water at pressures accessible in the laboratory will at best be superionic with high protonic conductivity5, but not metallic with conductive electrons1. Here we show that a metallic water solution can be prepared by massive doping with electrons upon reacting water with alkali metals. Although analogous metallic solutions of liquid ammonia with high concentrations of solvated electrons have long been known and characterized6–9, the explosive interaction between alkali metals and water10,11 has so far only permitted the preparation of aqueous solutions with low, submetallic electron concentrations12–14. We found that the explosive behaviour of the water–alkali metal reaction can be suppressed by adsorbing water vapour at a low pressure of about 10−4 millibar onto liquid sodium–potassium alloy drops ejected into a vacuum chamber. This set-up leads to the formation of a transient gold-coloured layer of a metallic water solution covering the metal alloy drops. The metallic character of this layer, doped with around 5 × 1021 electrons per cubic centimetre, is confirmed using optical reflection and synchrotron X-ray photoelectron spectroscopies
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Climate impact research: Beyond patchwork
Despite significant progress in climate impact research, the narratives that science can presently piece together of a 2, 3, 4, or 5 °C warmer world remain fragmentary. Here we briefly review past undertakings to characterise comprehensively and quantify climate impacts based on multi-model approaches. We then report on the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP), a community-driven effort to compare impact models across sectors and scales systematically, and to quantify the uncertainties along the chain from greenhouse gas emissions and climate input data to the modelling of climate impacts themselves. We show how ISI-MIP and similar efforts can substantially advance the science relevant to impacts, adaptation and vulnerability, and we outline the steps that need to be taken in order to make the most of the available modelling tools. We discuss pertinent limitations of these methods and how they could be tackled. We argue that it is time to consolidate the current patchwork of impact knowledge through integrated cross-sectoral assessments, and that the climate impact community is now in a favourable position to do so
Recommended from our members
Climate impact research: Beyond patchwork
Despite significant progress in climate impact research, the narratives that science can presently piece together of a 2, 3, 4, or 5 degrees C warmer world remain fragmentary. Here we briefly review past undertakings to characterise comprehensively and quantify climate impacts based on multi-model approaches. We then report on the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP), a community-driven effort to compare impact models across sectors and scales systematically, and to quantify the uncertainties along the chain from greenhouse gas emissions and climate input data to the modelling of climate impacts themselves. We show how ISI-MIP and similar efforts can substantially advance the science relevant to impacts, adaptation and vulnerability, and we outline the steps that need to be taken in order to make the most of the available modelling tools. We discuss pertinent limitations of these methods and how they could be tackled. We argue that it is time to consolidate the current patchwork of impact knowledge through integrated cross-sectoral assessments, and that the climate impact community is now in a favourable position to do so
Repurposing anthelmintic agents to eradicate resistant leukemia
Despite rapid progress in genomic profiling in acute lymphoblastic leukemia (ALL), identification of actionable targets and prediction of response to drugs remains challenging. To identify specific vulnerabilities in ALL, we performed a drug screen using primary human ALL samples cultured in a model of the bone marrow microenvironment combined with high content image analysis. Among the 2487 FDA-approved compounds tested, anthelmintic agents of the class of macrocyclic lactones exhibited potent anti-leukemia activity, similar to the already known anti-leukemia agents currently used in induction chemotherapy. Ex vivo validation in 55 primary ALL samples of both precursor B cell and T-ALL including refractory relapse cases confirmed strong anti-leukemia activity with IC50 values in the low micromolar range. Anthelmintic agents increased intracellular chloride levels in primary leukemia cells, inducing mitochondrial outer membrane depolarization and cell death. Supporting the notion that simultaneously targeting cell death machineries at different angles may enhance the cell death response, combination of anthelmintic agents with the BCL-2 antagonist navitoclax or with the chemotherapeutic agent dexamethasone showed synergistic activity in primary ALL. These data reveal anti-leukemia activity of anthelmintic agents and support exploiting drug repurposing strategies to identify so far unrecognized anti-cancer agents with potential to eradicate even refractory leukemia
The Theta+ (1540) as a heptaquark with the overlap of a pion, a kaon and a nucleon
We study the very recently discovered Theta+ (1540) at SPring-8, at ITEP and
at CLAS-Thomas Jefferson Lab. We apply the same RGM techniques that already
explained with success the repulsive hard core of nucleon-nucleon, kaon-nucleon
exotic scattering, and the attractive hard core present in pion-nucleon and
pion-pion non-exotic scattering. We find that the K-N repulsion excludes the
Theta+ as a K-N s-wave pentaquark. We explore the Theta+ as a heptaquark,
equivalent to a N+pi+K borromean bound-state, with positive parity and total
isospin I=0. We find that the kaon-nucleon repulsion is cancelled by the
attraction existing both in the pion-nucleon and pion-kaon channels. Although
we are not yet able to bind the total three body system, we find that the
Theta^+ may still be a heptaquark state. We conclude with predictions that can
be tested experimentally.Comment: 5 pages, 5 figures, 2 tables, submitted to Phys. Rev. D, rapid
communicatio
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