Geo-elektrische profielen bij de geologische en hydrologische detailkartering

Geoelectric traverses have been made in several regions of the F1anders, in order to test their usefulness for mapping purposes. The three regions selected had previously been covered by a grid of resistivity soundings mostly in Wenner arrangement.In the Beernem area different arrays have been used along the same line. These multiple traverses have provided data which allowed a comparison of the different arrays as well as a detailed subdivision in geoelectrical homogeneous zones coinciding with lithological units.Along traverse 136 GP/EE axial dipole measurements have been made over a distance of 2,7 km. For every point two values were determined : one for an array 2-20-2 and another for a 5-20-5 array. The first number stands for the length in meters of the current electrode separation, the third for the length of the voltage electrode separation, and the second for the distance between the two inner electrodes of bath dipoles.On the traverse 136-212 GP / AA Wenner arrangement perpendicular to the line has been used over a distance of 9,6 km to determine at each spot Q20' Q40' and Q80. Along the same line apparent resistivities have been measured with axial dipole arrays 2-20-2, 5-20-5, 5-40-5 and 10-40-10, parallel with the line.In the Westhoek area, a part of the coastal plain with salt-water encroachment in the unconfined aquifer, 21 traverses (194 GPW to 194 GPW21) have been run in the vicinity of Veurne (Furnes). The resistivities Q10 were measured by a longitudinal Wenner array. Since the traverses had been confined to a geoelectric homogeneous zone a quantitative interpretation could be performed. A relationship between Q10 and the depth of the saltwater - fresh water interface was computed from previous soundings. This relationship has been used to convert the apparent-resistivity data along the traverses into depth to interface values.The polder area of the F1emish Valley north of Ghent also has an unconfined aquifer with brackish water at variable depths. The situation is very similar to the one in the coastal plain although the variations here may not so readily find an explanation. One single traverse 142 GPW1 of 3550 m length has been run with a Wenner array for Q10. A relationship based upon former soundings has been used to convert resistivity data into interface depths.Resistivity traversing proves to be a very accurate and speedy tool for detailed mapping. Even a qualitative interpretation of a traverse, multiple if possible, can be sufficient to outline the boundaries between lithological or hydrogeological units. Quantitative interpretation is possible when in conjunction with a sounding grid, previously established, a relationship between the fixed electrode array and the unknown factor is found.Once a relationship is established, fixed-electrode separations allow a more detailed survey than resistivity soundings. These have to be long enough to obtain a reliable curve and hence average depth or resistivity data over longer a distance than fixed-electrode measurements which tend to be as short as possible. When traversing for qualitative purpose dipole arrangements have an advantage over Wenner arrangement in being speedier

Preinfection in vitro chemotaxis, phagocytosis, oxidative burst, and expression of CD11/CD18 receptors and their predictive capacity on the outcome of mastitis induced in dairy cows with Escherichia coli.

Four to 6 wk after parturition, 12 cows in second, fourth, or fifth lactation were experimentally infected in one gland with Escherichia coli. The capacity of chemotaxis, phagocytosis, oxidative burst, and expression of CD11/CD18 receptors to predict the severity of IMI was measured. Bacterial counts in the infected quarter, expressed as area under the curve, and residual milk production in the uninfected quarters were compared to determine severity of the infection. Although these two outcome parameters were highly negatively correlated, regression models with preinfection tests for leukocyte function fitted best with bacterial counts as an outcome parameter. Of the preinfection tests for leukocyte function, chemotaxis best predicted the outcome of the IMI that had been experimentally induced by E. coli. The number of circulating peripheral leukocytes just prior to inoculation was used to predict 52 and 45% of the severity of IMI for bacterial counts and residual milk production, respectively. As a categorical variable, parity predicted 75 and 56% of the severity of IMI expressed as bacterial counts and residual milk production, respectively. Because of the strong effect of parity on the outcome of the experimentally induced mastitis, analysis was performed to discriminate between second parity cows and older cows. Significant differences were found for the number of circulating peripheral leukocytes and for the expression of CD11b/CDl8 and CD11c/CD18 receptors between younger and older cows

Acute phase response in two consecutive experimentally induced E. coli intramammary infections in dairy cows

<p>Abstract</p> <p>Background</p> <p>Acute phase proteins haptoglobin (Hp), serum amyloid A (SAA) and lipopolysaccharide binding protein (LBP) have suggested to be suitable inflammatory markers for bovine mastitis. The aim of the study was to investigate acute phase markers along with clinical parameters in two consecutive intramammary challenges with <it>Escherichia coli </it>and to evaluate the possible carry-over effect when same animals are used in an experimental model.</p> <p>Methods</p> <p>Mastitis was induced with a dose of 1500 cfu of <it>E. coli </it>in one quarter of six cows and inoculation repeated in another quarter after an interval of 14 days. Concentrations of acute phase proteins haptoglobin (Hp), serum amyloid A (SAA) and lipopolysaccharide binding protein (LBP) were determined in serum and milk.</p> <p>Results</p> <p>In both challenges all cows became infected and developed clinical mastitis within 12 hours of inoculation. Clinical disease and acute phase response was generally milder in the second challenge. Concentrations of SAA in milk started to increase 12 hours after inoculation and peaked at 60 hours after the first challenge and at 44 hours after the second challenge. Concentrations of SAA in serum increased more slowly and peaked at the same times as in milk; concentrations in serum were about one third of those in milk. Hp started to increase in milk similarly and peaked at 36–44 hours. In serum, the concentration of Hp peaked at 60–68 hours and was twice as high as in milk. LBP concentrations in milk and serum started to increase after 12 hours and peaked at 36 hours, being higher in milk. The concentrations of acute phase proteins in serum and milk in the <it>E. coli </it>infection model were much higher than those recorded in experiments using Gram-positive pathogens, indicating the severe inflammation induced by <it>E. coli</it>.</p> <p>Conclusion</p> <p>Acute phase proteins would be useful parameters as mastitis indicators and to assess the severity of mastitis. If repeated experimental intramammary induction of the same animals with <it>E. coli </it>is used in cross-over studies, the interval between challenges should be longer than 2 weeks, due to the carry-over effect from the first infection.</p