Magnetic-field Induced Screening Effect and Collective Excitations

We explicitly construct the fermion propagator in a magnetic field background B to take the lowest Landau-level approximation. We analyze the energy and momentum dependence in the polarization tensor and discuss the collective excitations. We find there appear two branches of collective modes in one of two transverse gauge particles; one represents a massive and attenuated gauge particle and the other behaves similar to the zero sound at finite density.Comment: 5 pages, 3 figures; references on the zero sound added and typos correcte

Rethinking the Governance and Delivery of the Cohesion Policy Funds:Is the Recovery and Resilience Facility (RRF) a Model?

The Cohesion Policy Funds (CPF) have faced continuous debate about their effectiveness in reaching specified performance objectives, while at the same time advancing broader EU policy goals. The Recovery and Resilience Facility (RRF)’s “performance-based financing” model, where payment is based on the fulfilment of milestones and targets, rather than reimbursement of eligible costs, is sometimes presented as a superior alternative and possible inspiration for the future of the CPF. The RRF model centralises authority in the hands of national governments and promises tighter integration of investment and reforms, with monitoring focusing on results instead of receipts. In this context, it is crucial to understand more precisely how the RRF model differs from that of CPF and how the RRF model has been working out in practice, in order to draw lessons for the future of the CPF, which is the goal of this paper

Update on Radiation Dose From Galactic and Solar Protons at the Moon Using the LRO/CRaTER Microdosimeter

The NASA Lunar Reconnaissance Orbiter (LRO) has been exploring the lunar surface and radiation environment since June 2009. In Mazur et al. [2011] we discussed the first 6 months of mission data from a microdosimeter that is housed within the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) instrument onboard LRO. The CRaTER microdosimeter is an early version of what is now a commercially available hybrid that accurately measures total ionizing radiation dose in a silicon target (http://www.teledynemicro.com/product/radiation-dosimeter). This brief report updates the transition from a deep solar minimum radiation environment to the current weak solar maximum as witnessed with the microdosimeter

Reforming EU Pesticides Regulation, Rebuilding Public Support: Evidence from Survey Experiments in Six Member States:an ACES policy report

The authorization and use of pesticides in the European Union (EU) have become increasingly controversial and politically salient over the past decade. In particular the European Commission’s decision to re-authorize the use of glyphosate, the active substance in Bayer/Monsanto’s Roundup, after it had been classified a ‘probable human carcinogen’ by the International Agency for Research on Cancer (IARC), was highly controversial and triggered a lively debate on how to reform EU pesticide regulation. In this policy report, we assess whether and how specific reforms to decision-making procedures could impact public support for EU pesticides regulation, including acceptance of authorization decisions on controversial substances such as glyphosate. To do so, we first identified the main challenges of European pesticides regulation exposed by recent developments, including (but not limited to) the glyphosate controversy, as well as the actual and potential reforms proposed by the EU institutions, civil society organizations, academic commentators, and other stakeholders. We grouped these challenges and related reform proposals into four dimensions, namely: 1) the organization of the decision-making process; 2) the factors considered when authorizing pesticides; 3) sources of evidence and potential conflicts of interest; and 4) post-market monitoring and review of authorized pesticides. We then conducted a pair of linked online survey experiments on public attitudes toward reform of EU pesticides regulation in June 2020 among a representative sample of the adult population in six Member States (France, Germany, Italy, the Netherlands, Poland, and Sweden, n=9022). Our results show that the introduction of systematic post-authorization monitoring and review, and consideration of all relevant scientific studies in the authorization decision are the two most promising reforms to increase public support for pesticides regulation. Moreover, if a hypothetical glyphosate authorization decision is taken under a decision-making procedure that citizens (strongly) support, they are more likely to accept it even if they previously opposed this outcome. Our findings are particularly relevant given that glyphosate is currently again undergoing a renewal procedure in the EU

The first cosmic ray albedo proton map of the Moon

[1] Neutrons emitted from the Moon are produced by the impact of galactic cosmic rays (GCRs) within the regolith. GCRs are high-energy particles capable of smashing atomic nuclei in the lunar regolith and producing a shower of energetic protons, neutrons and other subatomic particles. Secondary particles that are ejected out of the regolith become “albedo” particles. The neutron albedo has been used to study the hydrogen content of the lunar regolith, which motivates our study of albedo protons. In principle, the albedo protons should vary as a function of the input GCR source and possibly as a result of surface composition and properties. During the LRO mission, the total detection rate of albedo protons between 60 MeV and 150 MeV has been declining since 2009 in parallel with the decline in the galactic cosmic ray flux, which validates the concept of an albedo proton source. On the other hand, the average yield of albedo protons has been increasing as the galactic cosmic ray spectrum has been hardening, consistent with a disproportionately stronger modulation of lower energy GCRs as solar activity increases. We construct the first map of the normalized albedo proton emission rate from the lunar surface to look for any albedo variation that correlates with surface features. The map is consistent with a spatially uniform albedo proton yield to within statistical uncertainties

The matrix realization of affine Jacobi varieties and the extended Lotka-Volterra lattice

We study completely integrable Hamiltonian systems whose monodromy matrices are related to the representatives for the set of gauge equivalence classes $\boldsymbol{\mathcal{M}}_F$ of polynomial matrices. Let $X$ be the algebraic curve given by the common characteristic equation for $\boldsymbol{\mathcal{M}}_F$. We construct the isomorphism from the set of representatives to an affine part of the Jacobi variety of $X$. This variety corresponds to the invariant manifold of the system, where the Hamiltonian flow is linearized. As the application, we discuss the algebraic completely integrability of the extended Lotka-Volterra lattice with a periodic boundary condition.Comment: Revised version, 26 page

Explicit Lie-Poisson integration and the Euler equations

We give a wide class of Lie-Poisson systems for which explicit, Lie-Poisson integrators, preserving all Casimirs, can be constructed. The integrators are extremely simple. Examples are the rigid body, a moment truncation, and a new, fast algorithm for the sine-bracket truncation of the 2D Euler equations.Comment: 7 pages, compile with AMSTEX; 2 figures available from autho