Influence of tree species on gross and net N transformations in forest soils

We compared N fluxes in a 150-year-old Fagus sylvatica coppice and five adjacent 25-year-old plantations of Fagus sylvatica, Picea abies, Quercus petraea, Pinus laricio and Pseudotsuga menziesii. We measured net N mineralization fluxes in the upper mineral horizon (A1, 0–5 cm) for 4 weeks and gross N mineralization fluxes for two days. Gross rates were measured during the 48-h period after addition of ¹⁵NH₄ and ¹⁵NO₃. Mineralization was measured by the ¹⁵NH₄ dilution technique and gross nitrification by ¹⁵NO₃ production from the addition of ¹⁵NH₄, and by ¹⁵NO₃ dilution. Net and gross N mineralization was lower in the soil of the old coppice, than in the plantations, both on a soil weight and organic nitrogen basis. Gross nitrification was also very low. Gross nitrification measured by NO₃ dilution was slightly higher than measured by ¹⁵NO₃ production from the addition of ¹⁵NH₄. In the plantations, gross and net mineralization and nitrification from pool dilution were lowest in the spruce stand and highest in the beech and Corsican pine stands. We concluded that: (1) the low net mineralization in the soil of the old coppice was related to low gross rate of mineralization rather than to the concurrent effect of microbial immobilisation of mineral N; (2) the absence of nitrate in the old coppice was not related to the low rate of mineralization nor to the absence of nitrifyers, but most probably to the inhibition of nitrifyers in the moder humus; (3) substituting the old coppice by young stands favours nitrifyer communities; and (4) heterotrophic nitrifyers may bypass the ammonification step in these acid soils, but further research is needed to check this process and to characterize the microbial communities.     

Polyethylene glycol-6000 as a clearing agent for lipemic serum samples from dogs and the effects on 13 serum assays

Polyethylene glycol-6000 (PEG) was evaluated as a clearing agent for lipemic serum from dogs. Effects of PEG-treatment in lipemic and non-lipemic samples were determined for 13 chemical and enzymatic assays (glucose, BUN, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, amylase, total protein, albumin, sodium, potassium, chloride, phosphorus, and calcium). Control samples for lipemic sera were prepared by ultracentrifugation. Treatment with PEG cleared all lipemic samples. Regression lines for all lipemic samples were highly significant (P less than 0.0001) and the SD of the control values around the regression lines were small compared with the mean value for an assay. The technique was simple, quick, and inexpensive. With proper validation, reliable predictions of true serum values could be calculated for lipemic serum samples for all assays studied.     

Dualisms shaping human-nature relations: discovering the multiple meanings of social-ecological change in Wayanad

This paper reflects on the impacts of agrarian change and social reorganisation on gender-nature relations through the lens of an indigenous group named the Kuruma in South India. Building upon recent work of feminist political ecology, I uncover a number of dualisms attached to the gender-nature nexus and put forward that gender roles are constituted by social relations which need to be analysed with regard to the transformative potential of gender-nature relations. Three main themes are at the centre of the empirical inquiry: gender subjectivities, rural off-farm employment and the human-nature nexus. I seek to show that, first, the production of gendered subjectivities cannot be simplified through essentialist assumptions that romanticise women’s relationships with nature; second, off-farm employment strategies both reinforce the social hierarchy in gender and contradict the Kuruma’s moral economies; and, finally, environmental and agrarian change redefine the use of agrobiodiversity and are related to ideas on progressive versus nonprogressive cultivation practices. The research is informed by qualitative research methods and offers a conceptual approach to the deconstruction of gender-nature relations from a poststructuralist feminist perspective.     

Balloon valvuloplasty for palliative treatment of tricuspid stenosis with right-to-left atrial-level shunting in a dog

A 3.75-year-old castrated male Chesapeake Bay Retriever was referred for evaluation of tachypnea, exercise intolerance, and cyanosis. Echocardiographically, there was severe tricuspid stenosis and right-to-left atrial-level shunting of blood. Marked compensatory polycythemia had developed; the PCV was 75%. Balloon dilation of the tricuspid stenosis was performed. Subsequent echocardiographic examinations demonstrated a reduction in the pressure gradient across the tricuspid valve. The PCV returned to the reference range, and the dog's clinical status improved during the 12 months after the procedure. Tricuspid stenosis is an uncommon lesion in dogs and, in the dog of this report, was assumed to have resulted from tricuspid dysplasia. Cyanosis was a result of right-to-left shunting of blood. Limited treatment is available for dogs with cyanotic heart disease. In this dog, balloon dilation of the stenotic tricuspid valve was palliative.     

Malignant melanoma of the coronary band in a horse

A malignant melanoma developed in the digit of a horse. Metastasis was extensive.     

Differenzierte quantitative Erfassung der Nettoammonifikation durch Pilze und Bakterien in Böden unter verschiedenen Pflanzengesellschaften

Determination of ammonification rate by fungi and bacteria in soils with different plant societies. In soil samples of three sites in decidous forests with different plant-ecological and plant-sociological characteristics an attempt was made to determine the contributions of the saprophytic ammonifying fungi and bacteria by selective inhibition and by the use of a special incubation technique. The stimulation of the soil microflora was carried out by the addition of a universal-pepton as an easily degradable organic nitrogen. For the selective inhibition of fungi and bacteria the broad-spectrum antibiotics cycloheximide and streptomycinsulfate were used, which had been tested and found suitable by Anderson and Domsch (1973). The determinations of the produced fractions of inorganic nitrogen were conducted by the use of ion-specific eletrodes. During the short period of incubation lasting for a maximum of 8 hours, feasible for calculation, only the NH,-N-contents of the soil material increased while the contents of NO,-N and NO,-N did not change during this period. The average contributions of the ammonifying soil microflora was calculated as follows: site I 80 %by fungi/20 %by bacteria site II 80 % by fungi/20 % by bacteria site III 65 %by fungi/35 % by bacteria. A relationship between the contributions of ammonifying fungi and bacteria and ecological characteristics of the sites could not be found.