Mineralisation of the longitudinal odontoid ligament in three horses identified on computed tomographic examination

Three horses that were presented for computed tomography (CT) examination of the head and cranial cervical spine in which marked mineralisation of the longitudinal odontoid ligament of the dens was identified on CT examination are described. There are currently no reports of mineralisation of the longitudinal odontoid ligament in horses in the literature. Although the significance of this finding to the presenting clinical problems in the cases described remains speculative, an association between mineralisation of the longitudinal odontoid ligament and compatible clinical signs merits further investigation. The purpose of this case report is to describe three cases with mineralisation of the longitudinal odontoid ligament as identified on CT examination.     

Hay strewing, brush harvesting of seed and soil disturbance as tools for the enhancement of botanical diversity in grasslands

Since the middle of the last century agricultural intensification within Europe has led to a drastic decline in the extent of botanically diverse grasslands. Whilst measures to enhance the diversity of agriculturally-improved grasslands are in place, success has often been limited. One of the primary factors limiting success is the paucity of sources of propagules of desirable species in the surrounding landscape. The restoration of two contrasting grassland types (lowland hay meadow and chalk grassland) was examined using a replicated block experiment to assess the effectiveness of two methods of seed application (hay strewing and brush harvesting) and two methods of pre-treatment disturbance (power harrowing and turf stripping). The resulting changes in botanical composition were monitored for 4 years. Seed addition by both methods resulted in significant temporal trends in plant species composition and increases in plant species richness, which were further enhanced by disturbance. Power harrowing increased the effectiveness of the seed addition treatments at the lowland hay meadow site. At the chalk grassland site a more severe disturbance created by turf stripping was used and shown to be preferable. Whilst both hay strewing and brush harvesting increased plant species richness, hay strewing was more effective at creating a sward similar to that of the donor site. Soil disturbance and seed application rate at the recipient site and timing of the hay cut at the donor site are all factors to be considered prior to the commencement of restoration management.     

The speciation of metals in sewage and activated sludge effluent

A gel filtration chromatography technique was used to separate soluble species of Cd, Cu, Co, Mn, Ni, and TI in the influent and effluent of a laboratory scale activated sludge simulation operated at a range of sludge ages from 3 to 18 days. It was found that, whilst there was no general trend for all six metals, Cd and Mn associated mainly with low molecular weight fractions; Co, Cu, and Ni with a range of predominantly high molecular weight fractions; and TI tended towards association with high molecular weight fractions which influenced metal solubility and appeared to be significant in determining metal removal. It appeared that all metals exhibited high affinity for mixed liquor suspended solids (MLSS) and that this affinity was strongest for Cu and Cd. Nickel, Co, Cu, and TI appeared to show a high affinity for polymeric microbial products produced at longer sludge ages. The gel filtration technique was found to be useful in the separation of metal species in conjunction with a sufficiently sensitive detector provided their concentrations in the original sample were relatively high.     

The use of magnetic resonance imaging for the assessment of distal limb wounds in horses: A pilot study

The utility of magnetic resonance (MR) imaging in the evaluation of equine solar foot penetrations is well established. The objective of this pilot study was to evaluate the utility of MR imaging in assessment of equine distal limb wounds excluding solar penetrations. Low-field MR images of 23 horses that had previously sustained distal limb wounds were reviewed in consensus by two ECVDI diplomats. Structures (bone; synovial structure; subcutaneous tissue and skin; and ligament/tendon) were identified as normal or abnormal on MR images, radiographs and ultrasound images and reports. All abnormalities were described. The presence of artefacts and their effect on image interpretation were also noted for each modality. Comparisons were made between imaging modalities, and it was noted if MR imaging influenced case management. Abnormalities of the bone were identified in 26% of horses on MR images and 17% of horses on radiographs; there were no osseous abnormalities identified on radiographs that were not identified on MR images, and additional features and better characterisation of lesions were noted on MR images. Tendon/ligament abnormalities were identified in 57% horses on MR and 47% of horses on ultrasound images. Magnetic susceptibility artefacts compromised MR image interpretation in 17% of horses. MR imaging of equine distal limb wounds allowed identification of both osseous and tendon/ligament abnormalities in more cases than either radiography or ultrasonography, and altered case management in 20/23 horses. Although MR imaging should not replace conventional imaging, this study highlights that MR imaging of equine distal limb wounds can yield information not detected on conventional imaging which may direct treatment and affect prognostication.     

Engineering considerations for water circulation in crawfish ponds with paddlewheel aerators

Engineering considerations for paddlewheel aeration in vegetated shallow water ponds for the production of procambarid crawfish is necessary to ensure cost-effective application. Three experimental ponds (approximately 2 ha each) were planted with rice in August as forage for the resident pond population of red swamp crawfish, Procambarus clarkii, and flooded in October. Two 2.2 kW (3 hp), single-phase electric motor (110 V_ac) paddlewheel aerators were placed in each pond. The aerator rotors were 160-cm long and 95-cm in diameter. The aerator rotor had 36 paddles with half the paddles 27.3-cm long and half 34.9-cm long. Rotor speed was set at 83 rpm and operated at three paddle submergence settings: 7.6, 12.7, and 17.8 cm below the water surface. Over a 20-week period between November and April, channel velocity, head difference, and aerator amperage was measured for both one and two aerators in operation in each pond. Results indicated that circulation of oxygenated water from the aerators can be accomplished as efficiently with a single aerator set at a lower paddle depth (7.6-cm) compared to operating two aerators set at a greater paddle depth (12.7 or 17.8-cm). However, based on the apparent efficiency of the aerators and the calculated channel roughness coefficients values obtained from the channel velocities, paddlewheel aerators are an inefficient option for circulating the pond water especially when rice foliage dominants the total vegetative biomass of the pond.     

Tracking environmental processes in the coastal zone for understanding and predicting Oregon coho (Oncorhynchus kisutch) marine survival

To better understand and predict Oregon coho (Oncorhynchus kisutch) marine survival, we developed a conceptual model of processes occurring during four sequential periods: (1) winter climate prior to smolt migration from freshwater to ocean, (2) spring transition from winter downwelling to spring/summer upwelling, (3) the spring upwelling season and (4) winter ocean conditions near the end of the maturing coho's first year at sea. We then parameterized a General Additive Model (GAM) with Oregon Production Index (OPI) coho smolt‐to‐adult survival estimates from 1970 to 2001 and environmental data representing processes occurring during each period (presmolt winter SST, spring transition date, spring sea level, and post‐smolt winter SST). The model explained a high and significant proportion of the variation in coho survival (R² = 0.75). The model forecast of 2002 adult survival rate ranged from 4 to 8%. Our forecast was higher than predictions based on the return of precocious males (‘jacks’), and it won't be known until fall 2002 which forecast is most accurate. An advantage to our environmentally based predictive model is the potential for linkages with predictive climate models, which might allow for forecasts more than 1 year in advance. Relationships between the environmental variables in the GAM and others (such as the North Pacific Index and water column stratification) provided insight into the processes driving production in the Pacific Northwest coastal ocean. Thus, coho may be a bellwether for the coastal environment and models such as ours may apply to populations of other species in this habitat.     

Early lesions of proliferative enteritis in pigs and hamsters

Gnotobiotic pigs and conventional hamsters were given suspensions of intestinal mucosa from a pig with proliferative hemorrhagic enteropathy and killed 10 or 21 days later. Affected animals had evidence of marked proliferation of immature enterocytes in the intestinal crypts. Numerous Campylobacter-like organisms were in the cytoplasm of enterocytes, and in some instances, bacteria were closely associated with enterocytes. Some intracellular bacteria lying below the microvillous border were within membrane-bound structures. Immunofluorescence and electron immunogold staining with specific antibodies indicated that these organisms were antigenically different from curved bacteria in the crypt lumen of early lesions. This study indicates that the life cycle of the intracellular organisms may involve entry into crypt enterocytes from the intestinal lumen with subsequent intracellular multiplication.     

Cassava and Maize Intercropping Systems — The Effects of Varieties and Plant Populations

Maize dominated cassava irrespective of cassava or maize growth habit and the optimum maize population giving the highest production based on relative yield total or land equivalent ratio varied with maize variety in a tropical Alfisol at Ibadan, transition humid/subhumid zone in West Africa. The sparsely vegetative, early maize supported higher intercrop maize population (up to 80,000 ha⁻¹) than the late maturing, highly vegetative TZSRW. Because there is a compensatory relationship in the yields of the two crop components, the choice of an appropriate crop type and maize population in cassava + maize intercrop system will depend on the relative economic importance of each crop component.