2,755 research outputs found
A framework for analyzing financial performance of the transport sector
This report presents a methodological framework for reviewing the financial performance of government agencies responsible for transport. The framework is applied in a detailed case study in Tanzania (the transport infrastructure of which is seriously run down) and on desk studies in 14 other countries. The report presents the following findings: (a) a weak revenue administration in Tanzania with only half of the airport user fees and road user charges collected; (b) an unduly complicated structure of user charges; (c) poorly controlled expenses; (d) out of line fuel prices compared with adjoining countries; (e) transport enterprises operating without clear financial objectives; and (f) financial affairs of enterprises being supervised by a ministry that lacked the expertise and authority to do so effectively. This paper outlines the steps recommended to strengthen financial performance and describes how their methodology can be used to prepare multiyear forward programs that can be linked to the net cash flow to/from the government.Banks&Banking Reform,Public Sector Economics&Finance,National Governance,Municipal Financial Management,Roads&Highways
Phase fluctuations and Non-Fermi Liquid Properties of 2D Fermi-system with attraction
The effect of static fluctuations in the phase of the order parameter on the
normal and superconducting properties of a 2D system with attractive
four-fermion interaction has been studied. Analytic expressions for the fermion
Green function, its spectral density and the density of states are derived. The
resultant single-particle Green function clearly demonstrates non-Fermi liquid
behavior. The results show that as the temperature increases through the 2D
critical temperature the width of the quasiparticle peaks broadens
significantly. At the same time one retains the gap in quasiparticle spectrum.
The spectral density for the dynamical fluctuations can also be obtained.
Clearly the dynamical fluctuations fill the gap giving the observed pseudogap
behaviour.Comment: 4 pages, LaTeX; invited paper presented at New^3SC-2, Las Vegas, USA,
199
Pseudogap phase formation in the crossover from Bose-Einstein condensation to BCS superconductivity in low dimensional systems
A phase diagram for a 2D metal with variable carrier density has been studied
using the modulus-phase representation for the order parameter in a fully
microscopic treatment. This amounts to splitting the degrees of freedom into
neutral fermion and charged boson degrees of freedom. Although true long range
order is forbidden in two dimensions, long range order for the neutral fermions
is possible since this does not violate any continuous symmetry. The phase
fluctuations associated with the charged degrees of freedom destroy long range
order in the full system as expected. The presence of the neutral order
parameter gives rise to new features in the superconducting condensate
formation in low dimensional systems. The resulting phase diagram contains a
new phase which lies above the superconducting (here
Berezinskii-Kosterlitz-Thouless) phase and below the normal (Fermi-liquid)
phase. We identify this phase with the pseudogap phase observed in underdoped
high- superconducting compounds above their critical temperature. We
also find that the phase diagram persists even in the presence of weak
3-dimensionalisation.Comment: 4 pages, LaTeX; invited paper presented at New^3SC-1, Baton Rouge,
USA, 1998. To be published in Int.J.Mod.Phys.
Photorespiration: metabolic pathways and their role in stress protection
Photorespiration results from the oxygenase reaction catalysed by ribulose-1,5-bisphosphate carboxylase/
oxygenase. In this reaction glycollate-2-phosphate is produced and subsequently metabolized in the
photorespiratory pathway to form the Calvin cycle intermediate glycerate-3-phosphate. During this metabolic
process, CO2 and NH3 are produced and ATP and reducing equivalents are consumed, thus
making photorespiration a wasteful process. However, precisely because of this ine¤ciency, photorespiration
could serve as an energy sink preventing the overreduction of the photosynthetic electron transport
chain and photoinhibition, especially under stress conditions that lead to reduced rates of photosynthetic
CO2 assimilation. Furthermore, photorespiration provides metabolites for other metabolic processes, e.g.
glycine for the synthesis of glutathione, which is also involved in stress protection. In this review, we
describe the use of photorespiratory mutants to study the control and regulation of photorespiratory pathways.
In addition, we discuss the possible role of photorespiration under stress conditions, such as
drought, high salt concentrations and high light intensities encountered by alpine plants
Persistence of pseudogap formation in quasi-2D systems with arbitrary carrier density
The existence of a pseudogap above the critical temperature has been widely
used to explain the anomalous behaviour of the normal state of high-temperature
superconductors. In two dimensions the existence of a pseudogap phase has
already been demonstrated in a simple model. It can now be shown that the
pseudogap phase persists even for the more realistic case where coherent
interlayer tunneling is taken into account. The effective anisotropy is
surprisingly large and even increases with increasing carrier density.Comment: 17 pages, LaTeX, 1 EMTeX figure; extended versio
Analysis of an Interplanetary Coronal Mass Ejection by a spacecraft radio signal: A case study
Tracking radio communication signals from planetary spacecraft with ground-based telescopes offers the possibility to study the electron density and the interplanetary scintillation of the solar wind. Observations of the telemetry link of planetary spacecraft have been conducted regularly with ground antennae from the European Very Long Baseline Interferometry Network, aiming to study the propagation of radio signals in the solar wind at different solar elongations and distances from the Sun. We have analyzed the Mars Express spacecraft radio signal phase fluctuations while, based on a 3-D heliosphere plasma simulation, an interplanetary coronal mass ejection (ICME) crossed the radio path during one of our observations on 6 April 2015. Our measurements showed that the phase scintillation indices increased by a factor of 4 during the passage of the ICME. The method presented here confirms that the phase scintillation technique based on spacecraft signals provides information of the properties and propagation of the ICMEs in the heliosphere
The Use of Maleic Hydrazide for Effective Hybridization of Setaria viridis
An efficient method for crossing green foxtail (Setaria viridis) is currently lacking. S. viridis is considered to be the new model plant for the study of C4 system in monocots and so an effective crossing protocol is urgently needed. S. viridis is a small grass with C4-NADP (ME) type of photosynthesis and has the advantage of having small genome of about 515 Mb, small plant stature, short life cycle, multiple tillers, and profuse seed set, and hence is an ideal model species for research. The objectives of this project were to develop efficient methods of emasculation and pollination, and to speed up generation advancement. We assessed the response of S. viridis flowers to hot water treatment (48°C) and to different concentrations of gibberellic acid, abscisic acid, maleic hydrazide (MH), and kinetin. We found that 500 μM of MH was effective in the emasculation of S. viridis, whilst still retaining the receptivity of the stigma to pollination. We also report effective ways to accelerate the breeding cycle of S. viridis for research through the germination of mature as well as immature seeds in optimized culture media. We believe these findings will be of great interest to researchers using Setaria
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