Role of surface roughness in hard x-ray emission from femtosecond laser produced copper plasmas

The hard x-ray emission in the energy range of 30-300 keV from copper plasmas produced by 100 fs, 806 nm laser pulses at intensities in the range of 10$^{15}-10^{16}$ W cm$^{-2}$ is investigated. We demonstrate that surface roughness of the targets overrides the role of polarization state in the coupling of light to the plasma. We further show that surface roughness has a significant role in enhancing the x-ray emission in the above mentioned energy range.Comment: 5 pages, 4 figures, to appear in Phys. Rev.

Spatial distribution of air-sea CO fluxes and the interhemispheric transport of carbon by the oceans

The dominant processes controlling the magnitude and spatial distribution of the preindustrial air-sea flux of CO are atmosphere-ocean heat exchange and the biological pump, coupled with the direct influence of ocean circulation resulting from the slow time-scale of air-sea CO gas exchange equilibration. The influence of the biological pump is greatest in surface outcrops of deep water, where the excess deep ocean carbon resulting from net remineralization can escape to the atmosphere. In a steady state other regions compensate for this loss by taking up CO to give a global net air-sea CO flux of zero. The predominant outcrop region is the Southern Ocean, where the loss to the atmosphere of biological pump CO is large enough to cancel the gain of CO due to cooling. The influence of the biological pump on uptake of anthropogenic CO is small: a model including biology takes up 4.9% less than a model without it. Our model does not predict the large southward interhemispheric transport of CO that has been suggested by atmospheric carbon transport constraints

Individual employee voice: renegotiation and performance management in public services

Periodically, the ‘zone of acceptance’ within which management may use its authority to direct employees’ work needs to be adapted to the changing needs of organisations. This article focuses especially on the non-codified elements of employees’ work, such as those commonly the subject of ‘psychological contracts’, and considers the role of individual employee voice in the process of adaptation, and how it relates to more familiar forms of collective employee voice. It is argued that the process can be analysed as a form of integrative bargaining, and applies the framework from Walton and McKersie. Employee voice enters into this process by virtue of consideration of the respective goals and preferences of both parties. The element of employee voice may be very weak when new work goals and priorities are imposed unilaterally by management, and they may be strong when full consideration is given to the changing needs of both parties. Two examples from work on performance management in the public services are used to illustrate these processes. The article concludes with a discussion of the ways in which collective employee voice may help to reinforce individual level integrative negotiation. The article seeks to contribute to the recent work on why employers choose employee voice mechanisms by broadening the range of policies that should be taken into account, and in particular looking at the potential of performance management as one such form

Pay for performance where output is hard to measure: the case of performance pay for school teachers

The introduction of performance-related pay with Performance Management in the state school sector of England and Wales represents a considerable change in the school management system. After 2000, all teachers were subject to annual goal setting performance reviews. Experienced teachers were offered an extended pay scale based on performance instead of seniority, and to gain access to the new upper pay scale, teachers had to go through a ‘threshold assessment’ based on their professional skills and performance. This paper reports the results of a panel survey of classroom and head teachers which started in 2000 just before implementation of the new system, and then after one and after four years of operation. We find that both classroom and head teacher views have changed considerably over time, from initial general skepticism and opposition towards a more positive view, especially among head teachers by 2004. We argue that the adoption of an integrative bargaining approach to performance reviews explains why a growing minority of schools have achieved improved goal setting, and improved pupil attainments as they have implemented performance management. Pay for performance has been one of the measures of organizational support that head teachers could bring to induce changes in teachers’ classroom priorities. We argue that the teachers’ case shows that a wider range of performance incentives than previously thought can be offered to employees in such occupations, provided that goal setting and performance measurement are approached as a form of negotiation instead of top-down

Increasing Finance, Improving Schools

Academic performance, Education finance,