49,412 research outputs found
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 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
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Recommended from our members
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
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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
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
Member Commitment and the Market and Financial Performance of the Saskatchewan Wheat Pool
Since 2001 several of the largest agricultural co-operatives in Western Canada and the United States have battled impending bankruptcy or ceased operations. In February 2001 Dairyworld Foods was bought out by Montreal dairy processor and cheese producer Saputo Inc. (Saputo; Toronto Stock Exchange). In November 2001, Agricore, formed through a 1998 merger of Alberta Wheat Pool Ltd. and Manitoba Pool Elevators, merged with United Grain Growers to form Agricore United (Agricore United). In the United States, AgWay and Farmland Industries filed for Chapter 11 bankruptcy protection in 2002 (Reuters, 2000), while the Saskatchewan Wheat Pool (hereinafter referred to as SWP or the Pool) underwent a massive debt restructuring in 2003 after four years of consecutive multi-million dollar net losses (SWP Annual Report, 2003). This decline in the market and financial performance of agricultural co-operatives has been associated with a decline in the commitment of the members to their co-operatives (Fulton, 1999; Fulton and Giannakas, 2001; Richards, Klein and Walburger, 1998; Burt and Wirth, 1990). The purpose of this article is to examine the market and financial performance of one of a number of co-operatives that have faced recent financial and market hardships, and to link this performance to member commitment. Specifically, the article examines whether the Pool’s declining market and financial performance is consistent with the predictions that emerge from a model that examines the impact of falling member commitment in a co-operative.Marketing,
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
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