19,188 research outputs found
Harmonic generation of noble-gas atoms in the Near-IR regime using ab-initio time-dependent R-matrix theory
We demonstrate the capability of ab-initio time-dependent R-matrix theory to
obtain accurate harmonic generation spectra of noble-gas atoms at Near-IR
wavelengths between 1200 and 1800 nm and peak intensities up to 1.8 X 10(14)
W/cm(2) . To accommodate the excursion length of the ejected electron, we use
an angular-momentum expansion up to Lmax = 279. The harmonic spectra show
evidence of atomic structure through the presence of a Cooper minimum in
harmonic generation for Kr, and of multielectron interaction through the giant
resonance for Xe. The theoretical spectra agree well with those obtained
experimentally.Comment: 6 pages, 5 figure
Dissipation in Mesoscopic Superconductors with Ac Magnetic Fields
The response of mesoscopic superconductors to an ac magnetic field is
investigated both experimentally and with numerical simulations. We study small
square samples with dimensions of the order of the penetration depth. We obtain
the ac susceptibitity at microwave frequencies as a
function of the dc magnetic field . We find that the dissipation, given
by , has a non monotonous behavior in mesoscopic samples. In the
numerical simulations we obtain that the dissipation increases before the
penetration of vortices and then it decreases abruptly after vortices have
entered the sample. This is verified experimentally, where we find that
has strong oscillations as a function of in small squares of
Pb.Comment: 4 pages, 2 figure
Reducing pitfalls in agricultural development projects: a case for the participatory project management cycle (PPMC)
The management of agricultural development projects is a factor that can contribute to their success or failure. In worst-case scenarios poorly managed projects seem to continue with a life of their own and without clear direction. In the cycle of agricultural development projects, including programmed extension, major pitfalls can occur if the necessary phases are ignored or incorrectly implemented. The argument is that these can be avoided if the Participatory Project Management Cycle (PPMC) is followed. While there are a number of methods available for trained agricultural extensionists these are not readily available for agricultural researchers who do not undergo such training but are often expected to carry out technology transfer. This is often done without the collaboration of trained extensionists. Subsequently, a method had to be developed using the basic project management knowledge that some agricultural researchers had obtained through experience and short courses. Two case studies are used to highlight what happens when the PPMC is followed or not. Case Study One is a project that was implemented to completion without following the Participatory Project Management Cycle. For the purpose of this study the PPMC was used during the ex-post evaluation to identify where and why major pitfalls occurred. Case Study Two concerns a project that was initiated using the PPMC but was temporarily suspended at the beginning of phase four of the cycle. This decision was based on the information obtained while following the PPMC and avoided the unnecessary use of scarce resources. Keywords: participatory project management cycle, agricultural development, case studies, Southern and Eastern Cape South African Journal of Agricultural Extension Vol. 34(1) 2005: 104-12
Transportation noise pollution - Control and abatement
Control and abatement of transportation noise pollutio
Effective Use of Secondary Data Analysis in Gifted Education Research: Opportunities and Challenges
Career Planning and Development: The Realities in Nigerian Organizations
Abstract: Employees are veritable sources of competitive advantage and planning and developing their careers is beneficial to both the organization and the employees. This study focuses on whether organizations in Nigeria give premium to career planning and development activities; the programmes engaged in and the perceived effectiveness of programmes generally. The investigation, which adopted a cross sectional survey and utilized structured questionnaire and interviews, centred on 10 firms in Rivers State, Nigeria. Data generated were analysed using descriptive statistics, specifically percentages and means, and simple regression. The results indicate that organizations recognize the need to invest in people and do embark on career planning and development programmes but employees do not perceive programmes as overly effective. Also, although firms recognize employees as important assets for organization success, they do not give as much attention to personal needs of employees as they do corporate needs. This is potentially counterproductive. Thus, we recommend the full incorporation of employees needs in career development activities so as to address the issues of employability of employees and long term competitiveness of organizations. Key words: Career planning resources; Career development programmes; Investing in people; Personal needs of employees; Employability; Perceived effectiveness; Nigeria organizatio
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