Evaluation of a process-based ecosystem model for long-term biomass and stand development of <Emphasis Type="Italic">Eucalyptus globulus</Emphasis> plantations

Versatile process-oriented ecosystem models are discussed as promising tools for the analyses of ecosystem services beyond wood yield, such as catchment water yield, sequestration of carbon and greenhouse gas balances. However, long-term yield simulation is often regarded as a weakness of such versatile models. In this context, we present a multiple response evaluation of the modular, process-based forest growth model MoBiLE-PDT based on mensurational data from 38 permanent sample plots in commercial Eucalyptus globulus plantations in Australia followed from establishment to 8 years of stand age. MoBiLE-PDT is based on the PnET-N-DNDC model and considers nitrogen availability and drought stress dynamically in dependence on tree and stand properties as well as on climate and deposition. New tree dimensions are calculated directly from carbon allocated to sapwood and mortality is derived from stand density. Towards the end of the rotation, model efficiency E was 0.58 for stand volume (m³ ha⁻¹) and 0.54 for aboveground biomass (t C ha⁻¹). In a comparison with similar forest growth models evaluated against the same data only one had a better model efficiency, whereas MoBiLE-PDT was the most versatile model for the analyses of ecosystem services. Due to its modular structure, further model extensions for more ecological applications are easily possible.     

Regionalizing soil properties in a catchment of the Bavarian Alps

Regionalizing information on soil hydraulic properties is a fundamental task for solving many soil related ecological problems at the landscape scale. The objective of this study was to derive this information from readily available topographical and geological data for the watershed of the Halbammer (42 km²) in the Bavarian Alps. The database consisted of 297 profiles taken during a 1 month field survey in summer 2001 and the topographical and geological maps (1:25,000) of the area. Soil profiles were grouped into six pedogenetic units taking into account the water regime of the profile and its texture. Another classification was done that relied only on texture and bedrock material as to describe the soil hydrological properties independently from their position in the landscape. In order to regionalize these classes, the tree based CART-Algorithm was used. This algorithm creates optimal classification trees based on a classified training sample and available parameters. The decision rules of these trees then served as basis for the derivation of soil maps that were created using the geographical information system ArcGIS 9.2. The accuracy of the regionalization was estimated using mathematical criteria as well as human expertise. Six to ten units proved to be a good number concerning the available data, but even then not all of them could be separated by CART. The performance of the CART algorithm is measured by the decrease of the misclassification error of an optimally pruned classification tree. In our study, the decrease of the misclassification reached 32 resp. 26% compared to a uniform classification of all data into the most frequent soil unit. The distributions of soil classes in the terminal nodes of the classification trees were useful for the interpretation of the soil units in the maps’ legends and also helped to identify typical soil patterns in the study area. According to these results, CART seems to be a suitable tool for regionalizing soil-related data, but human expertise is still needed to create plausible soil maps out of the information the CART algorithm provides.     

Orthotropic hygric and mechanical material properties of oak wood

The present study examines the three-dimensional hygric and mechanical behavior of oak wood. The moisture equilibrium state, characterized by the sorption isotherms, was obtained from measurements taken during adsorption and desorption cycles. Sorption behavior was analyzed with the Dent theory and compared considering the sorption direction (adsorption/desorption cycle). Sorption parameters were provided for possible numerical applications in hygric material models. The corresponding swelling and shrinkage behavior was examined and characterized by the moisture expansion parameters for all anatomical directions. Orthotropic mechanical material behavior was characterized by determining the elastic engineering (Young's moduli, shear moduli, and Poisson's ratios) and the bending, compressive and compressive shear strength material parameters. Influence of moisture content (MC) on the mechanical material properties was studied using Young's moduli, Poisson's ratios, and the investigated strength parameters. A significant difference between the sorption behavior in adsorption and desorption, known as the hysteresis effect, could be proved. Furthermore, swelling and shrinkage behavior did not show any dependency on the adsorption/desorption cycle. The results confirm the significant influence of MC on the Young's moduli and the strength properties, however, did not validate an influence on the Poisson's ratios.     

Concentrations of clindamycin in the mandibular bone of companion animals

Concentrations of clindamycin in the mandible were determined in 17 dogs and 13 cats with severe plaque, gingivitis/periodontitis, and calculus that were treated orally with clindamycin (11 mg/kg) once daily for 5 days prior to professional teeth cleaning and extractions. The animals were patients at the Dental Department of the Clinic for Surgery and Ophthalmology of the University of Veterinary Medicine in Vienna, Austria. Clindamycin levels were determined during postextractional alveoloplasty. Approximately 1 to 3 mm3 of mandible was removed from the intraradicular septum in multirooted teeth and from the protruding labial/buccal alveolar rim with a small rongeur. The mean concentration of clindamycin was 8.18 microg/g in dogs (range=3.16 to 24.08 microg/g) and 17.43 microg/g in cats (range=2.45 to 51.60 microg/g). The concentration of clindamycin in the mandibles of dogs and cats may be useful to combat infections after periodontal procedures, tooth extractions, or injuries to the mandible.     

Evaluation of Erysiphe graminis f sp tritici field isolates for resistance to strobilurin fungicides with different SNP detection systems

A single nucleotide polymorphism (snp) in the cytochrome b gene confers resistance to strobilurin fungicides in Erysiphe graminis DC fsp tritici Marchal. On the basis of this point mutation three different types of molecular markers have been developed. Cleaved amplified polymorphic sequences and allele-specific PCR were used to score resistant and sensitive isolates from specifically selected regional populations across Europe. The results of molecular tests were in total agreement with the resistance phenotypes revealed by in vivo tests. Serial dilutions of mixed samples (resistant/sensitive) delimited the detection for strobilurin-resistant alleles to a range of 10-50% for both marker classes. Due to these detection limits no mixture of mitochondria within individual isolates was found. Denaturing high performance chromatography was used to increase the detection sensitivity for the mutant allele. Although the detection limit was lowered to 5-10%, there was no evidence for the existence of mixed mitochondrial genotypes.     

Histologic and histochemical study of placentomes in cows after induced labor

The placentomes were extirpated from 16 cows after parturition induced with 750 micrograms cloprostenol or 20 mg dexamethasone on the 277th day of gravidity, on an average, from 9 cows after spontaneous parturition, and from 7 cows after hysterectomy in the eighth month of gravidity. In the cows with induced calving the foetal placenta was not expelled within 12 hours after calving in 68.7% of the cases whereas in the spontaneous parturitions this proportion was only 22.2% of cases. The placentomes obtained immediately after calf expulsion, and then after four and eight hours, were subjected to histological and histochemical examination. In the terminal crypts of the placentome in cross sections obtained from cows which expelled the placenta in time after natural and induced parturitions, the number of binuclear cells of the fetal syncytium and of cells of the dam epithelium (P less than 0.001) was found to be significantly lower than in the cases of afterbirth retention (1.2 and 3.9; 6.4 and 18.5). The cells of the cow's epithelium of the expelled placentae had a higher activity of acid phosphatase and lipids and the foetal syncytium had a higher activity of non-specific esterase. Increased alkaline phosphatase activity was characteristic of the cow's epithelium in the cases of subsequent retention of afterbirth. These findings should be taken into account in efforts for developing new methods of the induction of parturition if the undesired occurrence of afterbirth retention is to be reduced.     

Laparoscopic ovariectomy in mares using a polyamide tie-rap

OBJECTIVE: To describe use of a polyamide tie-rap to ligate the mesovarium during standing laparoscopic ovariectomy in mares. STUDY DESIGN: Prospective study. ANIMALS: Ten mares. METHODS: Bilateral ovariectomy was performed in 10 mares. Standing laparoscopic ovariectomy was performed using 3 portals in the paralumbar fossa. A commercial polyamide tie-rap was prepared as a loop and marked with 4 colored lines close to the buckle, to enable us to check whether the loop was tightened securely. The ovary was grasped with forceps and after the mesovarium was minimally transected cranially and caudally, the loop of the tie-rap was inserted in the abdomen and placed around the mesovarium. It was firmly tightened, until at least 3 of the 4 marks were visible, then the end of the tie-rap was cut. The ovary was transected and removed through an enlarged 3rd portal. The contralateral ovary was removed similarly through the opposite paralumbar fossa. Repeat laparoscopy was performed in 8 mares, 2, 3, 4, and 12 weeks later. RESULTS: None of the mares had postoperative discomfort. On repeat laparoscopy, there was complete encapsulation of the stump and tie-rap after 3-4 weeks. In 2 mares, an adhesion between the left stump and the mesentery of the descending colon was observed. CONCLUSION: Ligation of the mesovarium can be easily and safely performed using a polyamide tie-rap during standing laparoscopic ovariectomy in mares. CLINICAL RELEVANCE: Standing laparoscopic ovariectomy using a polyamide tie-rap is a safe, technically easy and reliable surgical procedure in the mare.     

Surgical correction of ear curling caused by scar tissue formation in a horse

An 18-month-old Belgian Warmblood mare was evaluated because it had injured the outer convex aspect of the left auricle. Second intention healing of the wound area caused tissue contracture, which resulted in the tip of the ear curling backward. By use of a technique involving undermining of the skin and a flap of granulation tissue on the medial aspect of the wound area and multiple incisions of the auricular cartilage, the curling was relieved and the ear regained a more normal shape. A skin graft was applied to cover the existing wound defect in an attempt to accelerate wound healing; thermoplastic material was contoured to fit the inner concave surface of the ear for immobilization and fixation of the ear in its final shape after surgery. Thirty days after surgery, the graft had healed completely and the ear had a normal conformation. The successful outcome of this treatment suggests that correction of an ear deformity secondary to scar tissue formation by use of an adapted surgical technique and appropriate materials can be achieved with good cosmetic results in horses.     

Effect of storage on bovine erythrocyte cholinesterase activity.

Bovine whole blood and washed erythrocyte samples with either sodium heparin or EDTA as the anticoagulant were stored at -24, 2 to 3, 21, or 37 C for up to 8 weeks to determine the stability of erythrocyte cholinesterase (ChE) activity. An automated colorimetric method was used to measure ChE activity. Regression analysis was used to estimate the rate of decline of ChE activity of samples to 95% of normal. Samples stored at -24 and 2 to 3 C were very stable, and ChE activity was maintained for several weeks or longer. Samples stored at 21 C maintained an activity level not less than 95% of normal for at least 9 days and those stored at 37 C for at least 2 days. The type of anticoagulant used did not appear to affect significantly the stability of activity.     

The effect of intramuscular administration of colistin on the development and course of experimentally induced oedema disease in weaned piglets

Shiga-toxigenic E. coli (STEC) strains that produce Shiga toxin Stx2e cause oedema disease in weaned piglets. The purpose of the present study was to investigate the impact of Stx2e released in mesenteric lymph nodes on disease pathogenesis. Colistin and ampicillin were intramuscularly administered to piglets of the experimental group simultaneously challenged with STEC strain, type O139:F18ab, Stx2e+. Piglets of the control group were challenged with STEC only. The strain was naturally resistant to ampicillin and susceptible to colistin. After the challenge, colonisation of the intestines was observed in both antibiotic-treated piglets and control piglets without antibiotic treatment. Histochemistry and scanning electron microscopy revealed sporadic colonisation of the small intestine in the piglets. STEC was detected in the mesenteric lymph nodes of untreated piglets. The clinical manifestations of oedema disease were observed in both groups. In the antibiotic-treated group (11 piglets), oedema disease developed in 10 piglets, eight of which died or were euthanized ante finem. In the untreated group (11 piglets), oedema disease developed in five piglets, four of which died or were euthanized ante finem. We therefore propose that the STEC lysed by colistin suddenly released the toxin from bacterial cells immediately after their passage through the intestinal wall. That could explain a more severe course of oedema disease in the treated piglets. Even though high amounts of STEC were present in the lymph nodes of untreated piglets, the toxin was not released abruptly because the bacterial cells were not damaged.