A heavily T2-weighted gradient-echo sequence was used for magnetic resonance (MR) imaging of the biliary system in five healthy volunteers and 13 patients with obstructive jaundice. Images were obtained in the sagittal and coronal planes during sequential breath-hold intervals and were post-processed by using a maximum-intensity projection algorithm. The extrahepatic and intrahepatic bile ducts were well visualized in 11 patients. The level of obstruction and the grade of dilatation were depicted with MR cholangiography. However, the cause of obstruction could be determined with MR cholangiography in only eight cases. The part of the biliary system below the obstruction could not be visualized with MR cholangiography. In the volunteers, MR cholangiography could demonstrate the anatomy of the biliary tract in only two subjects. Possible causes for this phenomenon are the limited spatial resolution of MR imaging, partial volume effects, or flow within the bile ducts. MR cholangiography may be a useful adjunctive tool for noninvasive evaluation of patients with obstructive jaundice. However, further technical advances are necessary to improve image quality.

Most existing soil loss data are spatially‐averaged, though various tracing techniques have been used for obtaining spatially‐distributed data. Spatially‐distributed soil erosion data are needed for validating physically‐based erosion prediction models and for better understanding soil erosion dynamics. The objectives of this study were to evaluate the feasibility of using rare earth element (REE) oxides directly as tracers for soil erosion studies by examining their binding ability with soil materials, and also to test a quick acid‐extraction procedure. Five REE oxide powders were directly mixed with a Miami silt loam soil (fine‐loamy, mixed, mesic Typic Hapludalfs) and then leached with deionized water in a soil box to evaluate the mobility of REEs. Following leaching, soil samples were sectioned in 25‐mm increments and analyzed for REEs. The REE‐tagged soil was wet sieved to obtain REE concentrations in each aggregate size group. A simple acid‐leaching method was used to extract REEs from all soil samples. The extracts were analyzed by Inductively Coupled Plasma‐Mass Spectrometry (ICP‐MS) techniques. The data indicated that the maximum coefficient of variation of the proposed procedure was <10% for all REEs. The REE oxides were uniformly incorporated into soil aggregates of different sizes (>53 μm) and were bound with silt‐size particles. This finding shows that the direct use of REE oxides is feasible, which should be superior to other REE‐tagged particulate tracers because it eliminates the need of tagging exotic particles with REEs. Also, direct mixing of a trace amount of REEs does not substantially alter physicochemical properties of soil particles and aggregates. This work has shown that REE oxides have a great potential for tracing soil erosion and aggregation.

To cite this version:V. Krömker, J. Friedrich. Teat canal closure in non-lactating heifers and its association with udder health in the consecutive lactation. Veterinary Microbiology, Elsevier, 2009, 134 (1-2) This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.Page 1 duration of open teat canals before calving and the udder health post partum was found. 18However, the incidence of clinical mastitis during first lactation was influenced largely by the 19 duration of infection ante partum and the mastitis pathogen involved. This study shows that a 20 high proportion of teat canals already opens several months before calving and that opening 21 of the teat canal before calving is an important factor in the aetiology of heifer mastitis. 22 23

ABSTRACTthese advantages will not be fully recognized unless the spatial and temporal predictability of process-basedSpatially averaged soil erosion data provide little information on models are validated. Thus, spatially distributed erosion soil erosion dynamics. Dynamically varied, spatially distributed erosion data are needed to better understand erosion processes and data are of great importance in advancing process-based thoroughly evaluate process-based erosion prediction models. The erosion prediction models.objectives of this study are to examine the feasibility of direct mixingVarious types of tracers have been developed and rare-earth element (REE) oxides with soil materials to trace soil used to obtain spatially distributed data. Commonly used erosion at a plot scale and to explore further the potential of using tracers include atomic bomb fallout radionuclide 137 Cs this technique to study soil erosion dynamics. Five REE oxide powders (Ritchie and McHenry, 1990; Walling and He, 1999 Pb provide little information on sediment origin. better understand soil erosion dynamics, but also for Unlike bomb-produced and cosmogenic radionuthorough validation of process-based erosion models.clides, radioactive elements can be manipulated and Spatially distributed soil erosion data are also useful deliberately introduced to study soil erosion. A major for evaluating on-site impacts such as effects of soil concern with this type of tracer is the radiological risk redistribution on crop yields and off-site impacts includto researchers and the environment. Exotic particles ing sediment origin and destination. Many processsuch as fluorescent glass or magnetic plastic beads have based erosion prediction models have been developed been used to overcome this concern, but suffer other in the past several decades to predict soil erosion at serious shortcomings. Major criticisms for exotic partivarious temporal and spatial scales (Nearing et al., 1989; cles are that (i) these particles may not bind with soil Hairsine and Rose, 1992; Borah, 1989). Since erosion particles or soil aggregates and therefore are transprocesses constantly change in time and space, processported separately; (ii) exotic particles differ in size distribased models have advantages over spatially and tempobution, particle density, shape, surface morphology, and rally lumped empirical prediction models. Element Applicationwith silt fractions. They also developed and tested a A wooden box (4 by 4 m) with adjustable slope was quick acid-leaching method for extracting REEs from used in the study. The box was arbitrarily set to a 10% soil and sediment samples for analysis by ICPMS. The slope, partially because it is close to the standard 9% quick extraction method makes it possible to take full slope used for developing the Universal Soil Loss Equaadvantage of this new technology. The advantages of tion. The sieved soil was packed into the soil box to a ICPMS as identified by Jarvis (1989) include exceptional depth of 0.2 m over a 0.5-m sand layer, wh...

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