Electron dynamics in the normal state of cuprates: spectral function, Fermi surface and ARPES data

An influence of the electron-phonon interaction on excitation spectrum and damping in a narrow band electron subsystem of cuprates has been investigated. Within the framework of the t-J model an approach to solving a problem of account of both strong electron correlations and local electron-phonon binding with characteristic Einstein mode $\omega _0$ in the normal state has been presented. In approximation Hubbard-I it was found an exact solution to the polaron bands. We established that in the low-dimensional system with a pure kinematic part of Hamiltonian a complicated excitation spectrum is realized. It is determined mainly by peculiarities of the lattice Green's function. In the definite area of the electron concentration and hopping integrals a correlation gap may be possible on the Fermi level. Also, in specific cases it is observed a doping evolution of the Fermi surface. We found that the strong electron-phonon binding enforces a degree of coherence of electron-polaron excitations near the Fermi level and spectrum along the nodal direction depends on wave vector module weakly. It corresponds to ARPES data. A possible origin of the experimentally observed kink in the nodal direction of cuprates is explained by fine structure of the polaron band to be formed near the mode -$\omega _0$

Hormone-treated beef: Should Britain accept it after Brexit?

This Briefing explains why the use of synthetic, industrially-manufactured hormones in beef production, and the threat of importing hormone-produced beef after Brexit, matter for UK consumers. There is robust scientific evidence showing that meat produced using one key hormone (17β-oestradiol) increases the cancer risk to consumers, while for the rest the available evidence is insufficient to show that their use is acceptably safe. The Briefing outlines the basis of the scientific and policy disputes over the use of supplementary hormones in beef cattle production. It shows that, although the USA is most associated with hormone-reared beef, other countries that want to export their beef to the UK, post Brexit, either allow hormones to be used, or are suspected of doing so. The EU has been reasonably vigilant on consumers’ behalf on this issue, and it has robust scientific grounds for its ban on their use. The risk from beef hormones is one of many issues on which UK consumers have benefited from the EU’s measures to protect public and environmental health. Chlorine-washed chicken is another example

Weakening UK food law enforcement: a risky tactic in Brexit

The UK Food Standards Agency (FSA) is beginning to roll out a far-reaching programme of regulatory change called Regulating Our Future (ROF). This Briefing Paper argues that ROF risks: - Making the UK’s food supply less safe by further weakening systems that are already too weak; - Undermining the ability of UK food producers to export to the EU after Brexit; - Creating irreconcilable conflicts of interests, because rather than having public officials inspect food businesses, the food businesses will be able to choose who ‘marks their homework’. Professors Erik Millstone (University of Sussex) and Tim Lang (City, University of London) provide a detailed and powerful critique of the Food Standards Agency’s proposals. They conclude that ROF represents a fundamental and detrimental shift in the role, approach and public responsibilities of the FSA and the local authority officers who are the bedrock of food safety in the UK. They also show why these unwelcome proposals are especially unwise in the context of negotiations over Brexit, when the public needs a strong, vigilant and effective FSA. The authors call for ROF to be halted pending further review by a special Parliamentary Joint Select Committee of the Health and Environment, Food & Rural Affairs Committees

Summary of the functions and capabilities of the structural analysis and matrix interpretive system computer program

Functions and capabilities of large capacity structural analysis and matrix interpretive system digital computer program to analyze frame and shell structure

Tool provides constant purge during tube welding

Tool provides a constant purge of inert gas during in-place welding of tubular components to prevent contamination and oxidation. It also permits self-jiggings of the tube and sleeve to be welded

Intracavity Dye-Laser Absorption Spectroscopy (IDLAS) for application to planetary molecules

Time-resolved, quasi-continuous wave, intracavity dye-laser absorption spectroscopy is applied to the investigation of absolute absorption coefficients for vibrational-rotational overtone bands of water at visible wavelengths. Emphasis is placed on critical factors affecting detection sensitivity and data analysis. Typical generation-time dependent absorption spectra are given