8,681 research outputs found
The state of EU law-making now resembles a political âHarlem shakeâ
This week, the European Parliament rejected the European Councilâs proposals on the EU budget for 2014-2020. While some believe this to be a victory for the Parliament in opposing budget cuts, negotiations are still to take place until a package deal is agreed between both institutions. Raya Kardasheva argues that while package lawmaking initially served as a flexible tool for negotiation among a select group of senior legislators, the process has now evolved outside institutional rules and it increasingly resembles the frantic group dance movements of this yearâs viral YouTube meme âHarlem shakeâ
Critical chiral hypersurface of the magnetized NJL model
In pursuit of the sketching the effective magnetized QCD phase diagram, we
found conditions on the critical coupling for chiral symmetry breaking in the
Nambu-Jona-Lasinio model in a nontrivial thermo-magnetic environment. Critical
values for the plasma parameters, namely, temperature and magnetic field
strength for this to happen are hence found in the mean field limit. The
magnetized phase diagram is drawn from the criticality condition for different
models of the effective coupling describing the inverse magnetic catalysis
effect.Comment: 8 pages, 8 figure
Greening through schooling:Understanding the link between education and pro-environmental behavior in the Philippines
In recent years, changing lifestyle, consumption and mobility patterns have contributed to a global rise in greenhouse gases responsible for the warming of the planet. Despite its increasing relevance, there is a lack of understanding of factors influencing the environmental behavior of people from emerging economies. In this study, we focus on the role of formal education for pro-environmental behavior in the Philippines and study three potentially underlying mechanisms explaining the education effects: differential knowledge about climate change, risk perceptions, and awareness. Whilst there is some evidence showing that education is associated with pro-environmental behavior, little is known about the actual mechanisms through which it influences decision-making. Using propensity score methods, we find that an additional year of schooling significantly increases the probability of pro-environmental actions, e.g. planting trees, recycling, and proper waste management, by 3.3%. Further decomposing the education effects, it is found that education influences behavior mainly by increasing awareness about the anthropogenic causes of climate change, which may consequently affect the perception of self-efficacy in reducing human impacts on the environment. Knowledge and perceptions about climate risks also explain the education effect on pro-environmental behavior, but to a lesser extent
Induced Bremsstrahlung by light in graphene
We study the generation of an electromagnetic current in monolayer graphene
immersed in a weak perpendicular magnetic field and radiated with linearly
polarized monochromatic light. Such a current emits Bremsstrahlung radiation
with the same amplitude above and below the plane of the sample, in the latter
case consistent with the small amount of light absorption in the material. This
mechanism could be an important contribution for the reflexion of light
phenomenon in graphene.Comment: 3 pages, 1 figure. To appear in Revista Mexicana de Fisic
Solving the Gap Equation of the NJL Model through Iteration: Unexpected Chaos
We explore the behavior of the iterative procedure to obtain the solution to
the gap equation of the Nambu-Jona-Lasinio (NLJ) model for arbitrarily large
values of the coupling constant and in the presence of a magnetic field and a
thermal bath. We find that the iterative procedure shows a different behavior
depending on the regularization scheme used. It is stable and very accurate
when a hard cut-off is employed. Nevertheless, for the Paul-Villars and proper
time regularization schemes, there exists a value of the coupling constant
(different in each case) from where the procedure becomes chaotic and does not
converge any longer.Comment: 16 pages, 11 figure
Chemical master versus chemical langevin for first-order reaction networks
Markov jump processes are widely used to model interacting species in circumstances where discreteness and stochasticity are relevant. Such models have been particularly successful in computational cell biology, and in this case, the interactions are typically rst-order. The Chemical Langevin Equation is a stochastic dierential equation that can be regarded as an approximation to the underlying jump process. In particular, the Chemical Langevin Equation allows simulations to be performed more eectively. In this work, we obtain expressions for the rst and second moments of the Chemical Langevin Equation for a generic rst-order reaction network. Moreover, we show that these moments exactly match those of the under-lying jump process. Hence, in terms of means, variances and correlations, the Chemical Langevin Equation is an excellent proxy for the Chemical Master Equation. Our work assumes that a unique solution exists for the Chemical Langevin Equation. We also show that the moment matching re- sult extends to the case where a gene regulation model of Raser and O'Shea (Science, 2004) is replaced by a hybrid model that mixes elements of the Master and Langevin equations. We nish with numerical experiments on a dimerization model that involves second order reactions, showing that the two regimes continue to give similar results
Mathematical and computational modelling of post-transcriptional gene relation by micro-RNA
Mathematical models and computational simulations have proved valuable in many areas of cell biology, including gene regulatory networks. When properly calibrated against experimental data, kinetic models can be used to describe how the concentrations of key species evolve over time. A reliable model allows âwhat ifâ scenarios to be investigated quantitatively in silico, and also provides a means to compare competing hypotheses about the underlying biological mechanisms at work. Moreover, models at different scales of resolution can be merged into a bigger picture âsystemsâ level description. In the case where gene regulation is post-transcriptionally affected by microRNAs, biological understanding and experimental techniques have only recently matured to the extent that we can postulate and test kinetic models. In this chapter, we summarize some recent work that takes the first steps towards realistic modelling, focusing on the contributions of the authors. Using a deterministic ordinary differential equation framework, we derive models from first principles and test them for consistency with recent experimental data, including microarray and mass spectrometry measurements. We first consider typical mis-expression experiments, where the microRNA level is instantaneously boosted or depleted and thereafter remains at a fixed level. We then move on to a more general setting where the microRNA is simply treated as another species in the reaction network, with microRNA-mRNA binding forming the basis for the post-transcriptional repression. We include some speculative comments about the potential for kinetic modelling to contribute to the more widespread sequence and network based approaches in the qualitative investigation of microRNA based gene regulation. We also consider what new combinations of experimental data will be needed in order to make sense of the increased systems-level complexity introduced by microRNAs
- âŠ