1,805 research outputs found
Rotational Corrections to in the NJL Model and Charge Conjugation
We show that the rotational corrections to , derived using the
semiclassical quantization scheme in the NJL model, possess correct properties
under charge conjugation.Comment: 4 pages, revtex, no figures, final version published in
Phys.Rev.C52(1995)42
The Bioeconomics of Controlling an African Rodent Pest Species
The paper treats the economy of controlling an African pest rodent, the multimammate rat, causing major damage in maize production. An ecological population model is presented and used as a basis for the economic analyses carried out at the village level using data from Tanzania. This model incorporates both density-dependent and density-independent (stochastic) factors. Rodents are controlled by applying poison, and the economic benefits depend on the income from maize production minus the costs for maize production, fertiliser and poison. We analyse how the net present value of maize production is affected by various rodent control strategies, by varying the duration and timing of rodenticide application. Our numerical results suggest that, in association with fertiliser, it is economically beneficial to control the rodent population. In general the most rewarding duration of controlling the rodent population is 3-4 months every year, and especially at the end of the dry season/beginning of rainy season. The paper demonstrates that changing from todays practice of symptomatic treatment when heavy rodent damage is noticed to a practice where the calendar is emphasised, may substantially improve the economic conditions for the maize producing farmers. This main conclusion is quite robust and not much affected by changing prices and costs of the maize production.bio-economics; pest control; multimammate rat; crop production
A Kohn-Sham system at zero temperature
An one-dimensional Kohn-Sham system for spin particles is considered which
effectively describes semiconductor {nano}structures and which is investigated
at zero temperature. We prove the existence of solutions and derive a priori
estimates. For this purpose we find estimates for eigenvalues of the
Schr\"odinger operator with effective Kohn-Sham potential and obtain
-bounds of the associated particle density operator. Afterwards,
compactness and continuity results allow to apply Schauder's fixed point
theorem. In case of vanishing exchange-correlation potential uniqueness is
shown by monotonicity arguments. Finally, we investigate the behavior of the
system if the temperature approaches zero.Comment: 27 page
Extreme precipitation related to circulation types for four case studies over the Eastern Mediterranean
International audienceThe analysis of the links between the extreme precipitation and the associated atmospheric conditions through an aloft circulation type approach at the 500-hPa geopotential level, for the time period of 1958?2000, is the main motivation for the present study. Four stations in the eastern Mediterranean (17.5° E to 37.5° E and 30° N to 40° N) were selected as separate case studies. The extreme precipitation conditions were defined by the two most widely used indices: the 90th and 95th percentiles. It was found that two cyclonic types (C ? with its centre over the station and Cwsw ? with its centre at the WSW of the station) were mainly associated with extreme rainfall conditions for all the selected stations. Generally, these circulation types are deepening during days with extreme precipitation in comparison to the general mean field of the type
Cyclones in the Mediterranean region: present and future climate scenarios derived from a general circulation model (HadAM3P)
International audienceIn this paper, an attempt is made to assess and evaluate the skill of the Hadley Center atmospheric General Circulation Model (HadAM3P) in generating successfully the frequency and intensity of severe cyclones (<1000 hPa) in the Mediterranean region. The cyclonic occurrence is studied in three regions of enhanced cyclonic activity: Gulf of Genoa, Southern Italy and Cyprus. It was found that the HadAM3P predicts a future decrease of the frequency of the severe cyclones at the SLP level, but the future cyclones will be more intense (deeper), especially at the 500 hPa level
Qualification Procedures of the CMS Pixel Barrel Modules
The CMS pixel barrel system will consist of three layers built of about 800
modules. One module contains 66560 readout channels and the full pixel barrel
system about 48 million channels. It is mandatory to test each channel for
functionality, noise level, trimming mechanism, and bump bonding quality.
Different methods to determine the bump bonding yield with electrical
measurements have been developed. Measurements of several operational
parameters are also included in the qualification procedure. Among them are
pixel noise, gains and pedestals. Test and qualification procedures of the
pixel barrel modules are described and some results are presented.Comment: 7 Pages, 7 Figures. Contribution to Pixel 2005, September 5-8, 2005,
Bonn, Germna
Error-resistant Single Qubit Gates with Trapped Ions
Coherent operations constitutive for the implementation of single and
multi-qubit quantum gates with trapped ions are demonstrated that are robust
against variations in experimental parameters and intrinsically indeterministic
system parameters. In particular, pulses developed using optimal control theory
are demonstrated for the first time with trapped ions. Their performance as a
function of error parameters is systematically investigated and compared to
composite pulses.Comment: 5 pages 5 figure
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