12 research outputs found
Comparison of and Quasielastic Scattering
We formulate -nucleus quasielastic scattering in a manner which closely
parallels standard treatments of -nucleus quasielastic scattering. For
scattering, new responses involving scalar contributions appear in
addition to the Coulomb (or longitudinal) and transverse responses
which are of vector character. We compute these responses using both nuclear
matter and finite nucleus versions of the Relativistic Hartree Approximation to
Quantum Hadrodynamics including RPA correlations. Overall agreement with
measured responses and new quasielastic scattering data for
Ca at |\qs|=500 MeV/c is good. Strong RPA quenching is essential for
agreement with the Coulomb response. This quenching is notably less for the
cross section even though the new scalar contributions are even more
strongly quenched than the vector contributions. We show that this
``differential quenching'' alters sensitive cancellations in the expression for
the cross section so that it is reduced much less than the individual
responses. We emphasize the role of the purely relativistic distinction between
vector and scalar contributions in obtaining an accurate and consistent
description of the and data within the framework of our nuclear
structure model.Comment: 26 pages, 5 uuencoded figures appended to end of this fil
Investment incentives for shipping
SIGLEAvailable from British Library Document Supply Centre- DSC:DX92087 / BLDSC - British Library Document Supply CentreGBUnited Kingdo
The policy implications of market failure for the land-based jobs market for British seafarers
People with seafaring experience and skills are employed in the maritime sector of the UK economy in land-based jobs as well as in seagoing ones. This paper examines the balance of supply and demand in the land-based jobs market. It then considers the likely effects of a shortfall in the supply of British ships' officers to fill net vacancies in jobs ashore, including the policy implications of this and the consequences for the economy's maritime skills base if the Government fails to act decisively now to correct market failure.UK seafarers Supply Land-based jobs Maritime skills base
Ex-seafarers shore-based employment: the current UK situation
The decline of the British shipping industry has had a significant impact on those sectors of the UK economy which have traditionally relied on ex-seafarers as a source of skilled labour. An in-depth study of the impacts of this problem was undertaken in 2003 to consider the implications of developments which have taken place in the industry since 1996. The UK economy's requirement for people with seafaring experience to fill land-based jobs was assessed, together with the implications of any shortfall. This paper considers the demand aspects of changes which have occurred since 1996.UK seafarers Demand Land-based jobs Maritime skills base
Earth as a Tool for Astrobiology - A European Perspective
International audienceScientists use the Earth as a tool for astrobiology by analyzing planetary field analogues (i.e. terrestrial samples and field sites that resemble planetary bodies in our Solar System). In addition, they expose the selected planetary field analogues in simulation chambers to conditions that mimic the ones of planets, moons and Low Earth Orbit (LEO) space conditions, as well as the chemistry occurring in interstellar and cometary ices. This paper reviews the ways the Earth is used by astrobiologists: (i) by conducting planetary field analogue studies to investigate extant life from extreme environments, its metabolisms, adaptation strategies and modern biosignatures; (ii) by conducting planetary field analogue studies to investigate extinct life from the oldest rocks on our planet and its biosignatures; (iii) by exposing terrestrial samples to simulated space or planetary environments and producing a sample analogue to investigate changes in minerals, biosignatures and microorganisms. The European Space Agency (ESA) created a topical team in 2011 to investigate recent activities using the Earth as a tool for astrobiology and to formulate recommendations and scientific needs to improve ground-based astrobiological research. Space is an important tool for astrobiology (see Horneck et al. in Astrobiology, 16:201â243, 2016; Cottin et al., 2017), but access to space is limited. Complementing research on Earth provides fast access, more replications and higher sample throughput. The major conclusions of the topical team and suggestions for the future include more scientifically qualified calls for field campaigns with planetary analogy, and a centralized point of contact at ESA or the EU for the organization of a survey of such expeditions. An improvement of the coordinated logistics, infrastructures and funding system supporting the combination of field work with planetary simulation investigations, as well as an optimization of the scientific return and data processing, data storage and data distribution is also needed. Finally, a coordinated EU or ESA education and outreach program would improve the participation of the public in the astrobiological activities