Traveling waves in a fluid layer submitted to a horizontal temperature gradient

We report experimental observations of traveling waves in a pure fluid with a free surface situated in a long container submitted to a horizontal temperature gradient perpendicular to its large extension. Above a critical value of the gradient and depending on the height of liquid $h,$ a source of waves is created in the container for small value of $h,$ while the system exhibits stationary patterns for larger values of $h.$ The spatio-temporal properties of the waves are studied and compared to theoretical predictions. Email contact: [email protected]: Saclay-S93/017 Email: [email protected]

Picaso: a computer language for art & design

PICASO is a computer language specifically designed to enable the artist/designer to use the digital computer as a graphic tool. It is a unique development in that it provides the artist for the first time, an integrated range of sophisticated graphic software in a format meaningful to the non-numerate user. This thesis examines the problem area of art and design, and reviews relevant computer software that is currently available. It continues to define the software requirements of the artist and designer, and illustrates how these are met by PICASO

Should we be treating animal schistosomiasis in Africa? The need for a One Health economic evaluation of schistosomiasis control in people and their livestock

A One Health economic perspective allows informed decisions to be made regarding control priorities and/or implementation strategies for infectious diseases. Schistosomiasis is a major and highly resilient disease of both humans and livestock. The zoonotic component of transmission in sub-Saharan Africa appears to be more significant than previously assumed, and may thereby affect the recently revised WHO vision to eliminate schistosomiasis as a public health problem by 2025. Moreover, animal schistosomiasis is likely to be a significant cost to affected communities due to its direct and indirect impact on livelihoods. We argue here for a comprehensive evaluation of the economic burden of livestock and zoonotic schistosomiasis in sub-Saharan Africa in order to determine if extending treatment to include animal hosts in a One Health approach is economically, as well as epidemiologically, desirable

Realistic forecasting of groundwater level, based on the eigenstructure of aquifer dynamics

Conference paper presented at the MODSIM03, International Congress on Modelling and Simulation, held July 2003, Jupiters Hotel and Casino, Townsville, Queensland.Short-term management of groundwater resources, especially during droughts, can be assisted by forecasts of groundwater levels. Such forecasts need to account for the natural dynamic behaviour of the aquifer, likely recharge scenarios, and recent but unknown abstractions. These requirements mean that forecasts, at say monthly intervals, need to be updated with current observations on a real-time basis. One established procedure for this kind of problem is to fit autoregressive, moving-average, exogenous-variable (ARMAX) time-series models to the history of groundwater levels in response to estimates of land surface recharge. The ARMAX difference equations are then converted into forecast equations that allow real-time updating to include recent forecast errors as an additional source of information. Some disadvantages of this pure time-series analysis approach are the apparent lack of physical concepts in the model formulation and statistical aspects of model identification and calibration that are related to the inherent structure of ARMAX equations. This paper addresses these issues by describing a method for formulating ARMAX forecast equations from a linear system description based on the eigenvalues and eigenvectors (eigenstructure) of the dynamic behaviour of an aquifer. For the piezometric response of a heterogeneous aquifer to a fixed spatial distribution of land surface recharge, with time-varying magnitude, only a few eigenvalues are significant for describing the dynamics. The resulting model has a simple robust parameter structure, and is easily calibrated and implemented in spreadsheet form. The eigenstructure approach enables transfer of some parameter information from locations with good data records to those with sparse data. This modelling approach is demonstrated with monthly values of land surface recharge, estimated from a daily water balance model, and groundwater level data from an observation well in a 2000 km² alluvial aquifer in Canterbury, New Zealand

A novel method for the detection and the quantification of RT-PCR products

Includes bibliographical references.Until recently, the measurement of mRNA levels was very time consuming and required specific parameters. With the advent of RT-PCR, mRNA fragments could be amplified and easily detected and measured. The amount of mRNA loaded into the reaction is proportional to the amount of product DNA. Here, we propose a new method for mRNA detection and quantification. The product of the amplification reaction is resolved electrophoretically on a polyacrylamide gel and then transferred to a positively charged nylon membrane. This membrane is then stained for DNA with a non-mutagenic dye. The membrane is converted to a visual image via a scanner. This image is then analyzed with the NIH Image program. The results show that this method is indeed of adequate sensitivity for comparisons of mRNA levels. Using this protocol, a linear relationship was shown between the amount of starting RNA and the amount of product DNA. This method is safer, less time consuming and at least as efficient as previously described methods.B.S. (Bachelor of Science