Spatial variability of switchgrass (Panicum virgatum L.) yield as related to soil parameters in a small field

The harvested biomass of switchgrass (Panicum virgatum L.) is generally much lower than its potential; this may be due to several factors including not recovering all the biomass at harvest, weed competition, pests, disease and spatial variation of soil features. The objective of this research was to quantify the yield spatial variation of switchgrass and relate it to soil parameters, in a field of about 5 ha, in 2004 and 2005. Several thematic maps of soil parameters and biomass yield were produced using GIS and geostatistical methods. Soil parameters changed consistently within very short distances and biomass yield varied from 3 to more than 20 Mg ha⁻¹. This remarkable variation indicates that the potential for increasing switchgrass productivity is a real prospect. Furthermore, spatial variation of yield showed similar patterns in the 2 years (r = 0.38^**), and therefore a major influence of site characteristics on switchgrass yield can be assumed to occur. Significant correlations were found between biomass yield and soil N, P, moisture and pH as well as between soil parameters. Some soil parameters such as sand content showed patchy spatial distribution. Conversely, a reliable spatial dependence could not be identified for other parameters such as P. Further research is needed.     

Attraction and antennal response of the common wasp,Vespula vulgaris (L.), to selected synthetic chemicals in New Zealand beech forests

BACKGROUND: The common wasp, Vespula vulgaris (L.), and the German wasp, Vespula germanica (F.), are significant problems in New Zealand beech forests (Nothofagus spp.), adversely affecting native birds and invertebrate biodiversity. This work was undertaken to develop synthetic attractants for these species to enable more efficient monitoring and management. RESULTS: Seven known wasp attractants (acetic acid, butyl butyrate, isobutanol, heptyl butyrate, octyl butyrate and 2,4‐hexadienyl butyrate) were field tested, and only heptyl butyrate and octyl butyrate attracted significantly higher numbers of wasps than a non‐baited trap. Accordingly, a series of straight‐chain esters from methyl to decyl butyrate were prepared and field tested for attraction of social wasps. Peak biological activity occurred with hexyl butyrate, heptyl butyrate, octyl butyrate and nonyl butyrate. Polyethylene bags emitting approximately 18.4–22.6 mg day^?1 of heptyl butyrate were more attractive than polyethylene bags emitting approximately 14.7–16.8 mg day^?1 of heptyl butyrate in the field. Electroantennogram (EAG) studies indicated that queens and workers of V. vulgaris had olfactory receptor neurons responding to various aliphatic butyrates. CONCLUSION: These results are the first to be reported on the EAG response and the attraction of social wasps to synthetic chemicals in New Zealand beech forests and will enable monitoring of social wasp activity in beech forests. Copyright © 2009 Society of Chemical Industry     

DUPLEX-ULTRASONOGRAPHIC EVALUATION OF THE COMMON CAROTID ARTERY IN THE RESTING, SEDATED AND ANESTHETIZED HORSE

The aim of this study was to determine the blood flow in the carotid artery during halothane anaesthesia by means of duplex-sonography. Seventeen warm blood horses were evaluated in dorsal and lateral recumbency and the results were compared with the values of the same horses resting and under sedation. The cross sectional area of the vessels, the time-averaged maximal blood velocity, time-averaged maximal blood flow and the resistance index were determined and the flow profile was evaluated. During halothane anesthesia the total blood flow shows a significant increase which is not dependent on the positioning of the horse. Mean blood velocity is decreased by sedation and significantly increased during anesthesia. Reduced peripheral resistance is expressed by a decline of the resistance index. After sedation and during recumbency there is an increase in diameter of the carotid artery.     

Characterisation of thirteen cowpea landraces from Umbria (Italy). Strategy for their conservation and promotion

Thirteen landraces of cowpea (Vigna unguiculata (L.) Walp. subsp. unguiculata cv. gr. Unguiculata) have been morphologically and agronomically characterised as part of a plan for safeguarding and protecting plant biodiversity typical of Lake Trasimeno (Umbria, central Italy). Sixty plants per accession were scored for plant vigour, growth habit, flower colour, days to flowering, days to first mature pod, pod length, total number of pods produced, seed colour pattern, 100 seed weight, total seed yield and virus susceptibility. With the exception of vigour and growth habit, all landraces appeared to be well differentiated from one another for all the characters considered. Strategies and problems related to their in situ conservation are discussed.     

A neoplasm of globule leukocytes in a cat

A neoplasm involving the ileo-cecal-colic junction, thymus, and tracheobronchial lymph nodes of a 7-year-old domestic cat was composed of dense sheets of round to oval mononuclear cells with oval to indented nuclei, moderate amounts of cytoplasm, and variable numbers of round eosinophilic granules. These granules are brown to black in phosphotungstic acid hematoxylin-stained sections and stain variably with the periodic acid-Schiff stain. They are 0.8 to 1.5 micron in diameter, limited by a single unit membrane, and have variable electron density. Light microscopic cellular morphology and staining characteristics as well as ultrastructural features of these cells are consistent with feline globule leukocytes. Morphologic features of the neoplastic cells in the present case are similar to those of the only other reported neoplasm of globule leukocytes which also involved the intestine of a cat.     

Spectroscopic investigation of electron donor-acceptor processes involving organic free radicals in the adsorption of substituted urea herbicides by humic acidsa

Products of the interaction between soil humic acids and substituted-urea herbicides were prepared in the laboratory and subjected to elemental, functional group, differential thermal, infrared spectroscopic and electron-spin resonance analysis, in order to examine the various chemical mechanisms that may take place upon adsorption. The results indicate that, besides the involvement of hydrogen bonding, a prominent role is played by electron donor-acceptor processes involving organic free radicals, which leads to the possible formation of charge-transfer complexes. The phytotoxicity of the urea herbicides, expressed as the inhibition potency towards the Hill reaction (pl₅₀ values), appeared to be correlated with their capacity to interact with soil humic components, and it is suggested that these two processes depend upon the same molecular parameters.