Administration of certain sedative drugs is associated with variation in sonographic and radiographic splenic size in healthy cats

Ultrasonography and radiography are standard diagnostic tests for cats with suspected splenic disease, however published information on outside sources of variation are currently lacking. The purpose of this prospective, randomized, crossover group study was to evaluate effects of common sedative drugs on the sonographic and radiographic characteristics of the spleen in healthy cats. Fifteen healthy adult research cats were randomly assigned into one of three groups corresponding to different sequences of administration of five sedative drugs/drug combinations (acepromazine; butorphanol; dexmedetomidine; midazolam and butorphanol (MB); and dexmedetomidine, butorphanol, and ketamine (DBK)), administered at 1‐week intervals. At each visit, three‐view abdominal radiographic and ultrasonographic examinations were performed prior to sedation and repeated 15‐30 min and 2‐3 h post sedation. Two board‐certified radiologists (one ACVR and one ACVR/ECVDI) evaluated the anonymized and randomized images. Acepromazine resulted in significantly increased sonographic and radiographic splenic measurements from baseline, which remained significantly increased 2‐3 h post sedation. The mean magnitude of this change ranged from 0.9 mm (tail height, SD 1.4 mm) to 1.8 mm (body height, SD 1.7 mm) for ultrasound, and was 2.2 mm (ventrodorsal width, SD 2.3 mm) for radiographs. With butorphanol, there was no significant change in splenic size. For dexmedetomidine, MB, and DBK, there was a trend toward increased splenic size from baseline to the first post‐sedation timepoint, which was statistically significant for radiographic measurements, although not for ultrasound. Findings indicated that acepromazine should be avoided prior to imaging while butorphanol may be used when sedation is needed in cats presenting for potential splenic disease.     

Die Jagd im klassischen Hellas

Ohne Zusammenfassung     

Use of geophysical methods for the study of sandy soils under Campinarana at the National Park of Viruá, Roraima state,Brazilian Amazonia

Purpose

The vegetation of the Campinaranas occurs in humid areas with hydromorphic sandy soils at the Amazon region. Thus, the determination and in situ monitoring of moisture content in Campinarana soils, besides the detection of subsurface layers are key measures for studying these soil–vegetation systems. Also, the application of ground penetrating radar (GPR) in deep sandy sedimentary sequence of Amazonia is a promising tool to enhance the knowledge on depositional and soil formation features.

Materials and methods

We studied representative soils of the Campinaranas at the National Park of Viruá, state of Roraima (Brazilian Amazonia), through the use of geophysical methods (soil moisture sensors and GPR). The study was applied in four sandy soils. Besides chemical and physical analysis of soils, soil moisture sensors were installed for monitoring during an entire hydrological year (2010/2011), and performed the calibration of sensors , coupled with imaging of the soil along transects with GPR.

Results and discussion

As a result of calibration of the soil moisture sensors we obtained a general equation with an R ² greater than 0.9. There is an influence of soil moisture content and soil temperature in the distribution of vegetation types in Campinaranas. The use of GPR identified some determinants characteristics in these soils for the differentiating the Campinaranas, represented by spodic and C horizons.

Conclusions

The spodic horizons in soils under Forest Campinarana provided potential errors in the determination of soil moisture, requiring calibration data for the precise use of this device. The investigation of the soil through the GPR showed interesting results, which allowed continuous visualization of the main soil horizons along transects in the phytophysiognomies of Campinaranas.     

Water-dispersible clay after wetting and drying cycles in four Brazilian oxisols

Widespread intensive land use in the seasonal tropics can damage the physical stability of aggregates. Similar damage can be expected from wetting and drying cycles causing aggregate fragmentation and, consequently, leading to an increase in their specific area and exposure of internal electric charges. Thus, we hypothetised that the influence of wetting and drying cycles is dependent on the mineralogical composition of oxisols (latosols) and it is higher in soils with low aggregate stability. A greenhouse experiment was carried out to test this hypothesis in highly weathered soils from Brazil, all with variable-charge clays and highly stable aggregates. Wetting and drying cycles were defined from the quantity of water available between field capacity and the permanent wilting point. Soil columns were submitted to 0, 2, 6, 9, 12, 15 and 18 wetting and drying cycles. After each number of wetting and drying defined physical and chemical properties were determined. Statistical analysis, such as simple and multiple linear regression and Pearson's correlation were performed, showing significantly correlated WDC contents with wetting and drying cycles. The obtained results led to the conclusion that there was a close interdependence among mineralogical composition, aggregate stability and WDC influenced by wetting and drying cycles. Soils of reduced aggregate stability like kaolinitcs made them more susceptible to the action of wetting and drying on the WDC. Changes in the WDC with wetting and drying cycles showed correlated with eletrochemical properties.     

Long-term decline in the abundance of leafhoppers and planthoppers (Auchenorrhyncha) in Central European protected dry grasslands

Landscapes in Central Europe have changed considerably during the last five decades, while nature reserves have been less affected. However, there is growing concern that species richness and population size of animals in reserves may decrease even under protection.We performed a comparative study of the development in auchenorrhynchan communities of governmentally protected dry grasslands in Eastern Germany and tested whether reserves were effective in maintaining insect communities. The historical surveys are from 1963 to 1967. Between 2008 and 2010 we revisited 26 of the original sites and sampled leafhoppers and planthoppers by applying the same sampling technique as in the 1960s. Thus, we were able to perform a 40-year-comparison for auchenorrhynchan species richness and abundance. Comparisons capturing three successive years of each period allowed us to assess interannual variability in abundance.Species richness hardly differed between the two periods. However, some new species were found, and therefore species composition changed. Species abundance and overall numbers of individuals declined. Mainly species known to be very common dry grassland specialists exhibited strong declines in abundance. On average, only 27% of auchenorrhynchan numbers caught from 1964 to 1966 were recorded for the years 2008 to 2010.The results suggest that weather conditions and climate change are minor factors in the decline in auchenorrhynchan populations in recent years. Although the studied areas were under protection during the last 50 years, air-borne nitrogen deposition, the introduction of modern intense land use practices and alterations in plant communities, are likely to have influenced auchenorrhynchan abundance to a large extent.     

Habitat selection by the pale-headed brush-finch (Atlapetes pallidiceps) in southern Ecuador: implications for conservation

The pale-headed brush-finch (Atlapetes pallidiceps) is threatened with extinction due to habitat loss, but very little is known about its ecological requirements. We used multiple logistic regression to study habitat selection of this species at landscape, territory, and nest site scales in order to make recommendations about effective management. Habitat selection by the sympatric stripe-headed brush-finch (Buarremon torquatus) was examined with the same methods in order to analyse interspecific resource partitioning and potential competition. The pale-headed brush-finch selected semi-open habitat types with intermediate scrub heights, and avoided forests. Nest sites depended on the presence of vines or bamboo. By contrast, the stripe-headed brush-finch chose dense habitat with low ground cover under tall vegetation and avoided semi-open habitat. The two species had overlapping territories but differed significantly in microhabitat use and the use of vegetation strata. We found no convincing evidence that the stripe-headed brush-finch displaces the pale-headed brush-finch from optimal habitat. The preservation of semi-open scrubland maintained by low-intensity grazing is suggested for future conservation of the pale-headed brush-finch.     

The Landfill of TBT Contaminated Harbour Sludge on Rinsing Fields—a Hazard for the Soil Fauna? Risk Assessment with Earthworms

Despite the cutback of the use of antifouling paints containing tributyltin (TBT), harbour sediments are still “hot spots” for organotin pollution, which is one of the most toxic substances for aquatic organisms. Harbours have to be freed constantly of suspended sediments, to guarantee unhindered shipping. The deposition of these TBT contaminated sediments on rinsing fields is supposed to comprise a minimisation of the risk potential for humans and environment. To investigate if TBT contaminated sediment might present a hazard to the existing soil fauna, a risk assessment with earthworms was performed. The original TBT contaminated sediment induced 94% mortality, compared to 2% in the uncontaminated standard Lufa soil. It was assumed that the high salinity (23 dS/m) was the reason for the mortality rather than the TBT concentration of 600 μg/kg soil (dry weight). To reduce the soil salinity, the TBT substrate was first washed with deionised water and then mixed with the uncontaminated artificial OECD soil (=TBT_mix), which resulted, however, in a lower TBT concentration (132 μg/kg soil dw.). The uncontaminated OECD reference soil resulted in high earthworm mortality (34%). Despite the reduced salinity (10 dS/m) and lower TBT concentration, the TBT_mix substrate induced high mortality rates (42%), reduced reproduction (17% compared to the control) and resulted in a significant substrate avoidance of 92%. Consequently, the landfilling of the TBT contaminated harbour sludge might (i) present a hazard to the existing soil fauna at the rinsing fields due to high salinity and the TBT contamination, and (ii) a quick recolonisation of the contaminated substrate by earthworms can not be expected.     

Above- and belowground carbon inputs affect seasonal variations of soil microbial biomass in a subtropical monsoon forest of southwest China

Soil microbial activity drives carbon and nutrient cycling in terrestrial ecosystems. Soil microbial biomass is commonly limited by environmental factors and soil carbon availability. We employed plant litter removal, root trenching and stem-girdling treatments to examine the effects of environmental factors, above- and belowground carbon inputs on soil microbial C in a subtropical monsoon forest in southwest China. During the experimental period from July 2006 through April 2007, 2 years after initiation of the treatments, microbial biomass C in the humus layer did not vary with seasonal changes in soil temperature or water content. Mineral soil microbial C decreased throughout the experimental period and varied with soil temperature and water content. Litter removal reduced mineral soil microbial C by 19.0% in the ungirdled plots, but only 4.0% in girdled plots. Root trenching, stem girdling and their interactions influenced microbial C in humus layer. Neither root trenching nor girdling significantly influenced mineral soil microbial C. Mineral soil microbial C correlated with following-month plant litterfall in control plots, but these correlations were not observed in root-trenching plots or girdling plots. Our results suggest that belowground carbon retranslocated from shoots and present in soil organic matter, rather than aboveground fresh plant litter inputs, determines seasonal fluctuation of mineral soil microbial biomass.