Is the relative abundance of nonnative species an integrated measure of anthropogenic disturbance?

The hypothesis that the percentage of nonnative plant species inhabiting a landscape might be used as an integrated measure of anthropogenic disturbance was explored in 26 diverse landscape parcels in Rhode Island. Nine correlates of anthropogenic disturbance within, and immediately adjacent to the refuges were compared to two refuge-specific indices of relative nonnative vascular plant species abundance. The percentage of the total vascular flora of each refuge that was nonnative was the Nonnative Index for each refuge. The percentage of all nonnative species in the 26 refuges combined that occurred in a given refuge was the Regional Nonnative Index for each refuge (nonnative species in each refuge divided by the nonnative species in all 26 refuges, times 100). The latter index measured how successful species from the finite pool of nonnative species present in the region were at invading and colonizing a refuge. Of the 869 vascular plant species in all 26 refuges, 28% were nonnative. The percentage of the vascular flora that was nonnative in each refuge varied from 2 to 50%. Few comparisons between correlates of anthropogenic disturbance and Nonnative Indices were statistically significant, yet two of the nine correlates of anthropogenic disturbance were highly related to Regional Nonnative Indices. Collectively, the correlates of anthropogenic disturbance accounted for 39% of the variance in the Regional Nonnative Index for all species combined, and 56% of the variance in the Regional Nonnative Index for tree species alone. The Regional Nonnative Index was also highly related to the richness of native plant species. The hypothesis that the nonnative vascular plant diversity of a landscape can be used as a surrogate for the integrated effects of anthropogenic disturbance was generally rejected by the analysis of our Nonnative Index, and supported by the analysis of our Regional Nonnative Index.     

Feline infectious peritonitis. An immune-mediated coronaviral vasculitis

Mainly through studies inducing experimental infection of susceptible cats, significant advances have recently been made in our understanding of the pathogenesis of FIP. Much of this knowledge should not presently be directly extrapolated to field cases of FIP, because the route of infection and challenge dose and strain of virus may be significantly different. Advances in the prevention and treatment of FIP will depend greatly on clarification of the exact nature of the several coronaviruses affecting cats and the role of cell-mediated immunity in resistance to FIPV.     

Some investigations of suspoemulsions

‘Suspoemulsions’ (SE) is the term used to describe combined formulations of solid and liquid active ingredients as dispersed systems. The parameters influencing an SE were investigated with reference to four examples (one solid and three liquid products) in various mixing ratios. Apart from the type and amount of the partners and the energy dissipation density used, the recipe and viscosity particularly had effects on the formation and properties of an SE. The solid particles in the suspension promoted the comminution of the liquid phase. However, they had practically no influence on the flow behaviour in the three degrees of comminution fineness investigated. The causes of the phenomena discovered are discussed. The storage stability of the SE was equal to that of suspension concentrate (SC) formulations. The advantageous effect of the addition of a thickener on storage stability was similar to that in the case of an SC.     

Influence of femoral head and neck conformation on hip dysplasia in the German Shepherd dog.

We investigated the prevalence of an anatomic variant of the proximal femur, termed the broomstick-like femoral head and neck formation, and its influence on the Féderation Cynologique Internationale (FCI) hip dysplasia score in 294 German Shepherd dogs. One-hundred and eighty (61%) of the 294 dogs in our study had this anatomic variant. The calculated area of the femoral heads in dogs with a broomstick-like conformation was 4.5 +/- 0.6 cm2 on the hip-extended view. In dogs with a normal femoral head, the calculated area of the femoral head was significantly larger at 4.8 +/- 0.6 cm2 (P < 0.05). In the frog-leg view, there was no significant difference in femoral head area between dogs with the broomstick-like conformation and normal dogs. There was no difference in the antetorsion angle between dogs with broomstick-like conformation and normal dogs. There was also no difference in the distraction ratio between the two phenotypes. The official FCI hip score was similar in dogs with and without the broomstick-like conformation. The average heritability of the broomstick-like conformation was 0.3 +/- 0.1, suggesting heritable influence. We conclude that the broomstick-like conformation is a common finding in the German shepherd dog and has genetic base. The broomstick-like conformation does not appear to be associated with the presence of canine hip dysplasia and it can therefore be assumed to be a normal anatomic variant.     

Nitrous oxide emissions from arable soils in Germany — An evaluation of six long‐term field experiments

In this study emissions of N₂O from arable soils are summarized using data from long‐term N₂O monitoring experiments. The field experiments were conducted at six sites in Germany between 1992 and 1997. The annual N‐application rate ranged from 0 to 350 kg N ha^—1. Mineral and organic N‐fertilizer applications were temporarily split adapted to the growth stage of each crop. N‐fertilizer input and N‐yield by the crops were used to calculate the In/Out‐balance. The closed chamber technique was applied to monitor the N₂O fluxes from soil into the atmosphere. If possible, plants were included in the covers. Annual N₂O emission values were based on flux rate measurements of an entire year. The annual N₂O losses ranged from 0.53 to 16.78 kg N₂O‐N ha^—1 with higher N₂O emissions from organically fertilized plots as compared to minerally fertilized plots. Approximately 50% of the total annual emissions occurred during winter. No significant relationship between annual N₂O emissions and the respective N‐fertilization rate was found. This was attributed to site‐ and crop‐specific effects on N₂O emission. The calculation of the N₂O emission per unit N‐yield from winter cereal plots indicates that the site effect on N₂O emission is more important than the effect of N‐fertilization. From unfertilized soils at the sites Braunschweig and Timmerlah a N‐yield of 60.0 kg N ha^—1 a^—1 and N₂O emissions of 2 kg N ha^—1 a^—1 were measured. This high background emission was assigned to the amount and turnover of soil organic matter. For a crop rotation at the sites Braunschweig and Timmerlah the N In/Out‐balance over a period of four years was identified as a suitable predictor of N₂O emissions. This parameter characterizes the efficiency of N‐fertilization for crop production and allows for N‐mineralization from the soil.     

Extending Shelf Life of Chilled Pork by Combination of Chitosan Coating With Spice Extracts

The effects of spices（cinnamon,rosemary,clove）extracts and chitosan on microbiological growth,drip loss,color,and lipid oxidation of fresh chilled meat stored for 28 days at 4℃were investigated.There were four treatments：control,coated with spices（cinnamon 1.5 g·L^-1＋rosemary 1.5 g·L^-1＋clove 1.0 g·L^-1）,coated with 0.5%chitosan,coated with spices and chitosan.Chitosan coating resulted in significant inhibition of microbial growth（P〈0.05）,while the lowest microbial counts were obtained in the samples containing both chitosan and spices,indicating a possible synergistic effect.Chitosan and its combinations with spices also showed the most intense antioxidative effect when compared to the controls（P〈0.05）.Meanwhile,chitosan coating could decrease water loss and keep better color of chilled meat.The combined spice extracts and chitosan coating could effectively extend the shelf life of chilled meat.     

MR-imaging of lumbosacral intervertebral disc degeneration in clinically sound German shepherd dogs compared to other breeds

German shepherd dogs are overrepresented in the group of dogs with cauda equina compression syndrome due to degenerative lumbosacral stenosis. A congenital predisposition for early degeneration of the lumbosacral intervertebral disc has been suspected. Our aims were to assess the morphologic appearance of the lumbosacral intervertebral disc and the lumbosacral junction in healthy German shepherd dogs compared to other breeds and to evaluate for an early onset of degenerative changes. The lumbosacral spine of 110 clinically sound German shepherd dogs and 47 healthy dogs of other large breeds was examined using magnetic resonance (MR) imaging. The degeneration of every intervertebral disc was graded using an established classification system. Signal intensity of the entire lumbosacral disc and the nucleus pulposus was determined independently. Lumbosacral malalignment was assessed according to a previously described method. The findings for the German shepherd dogs were compared to those of the other breeds. Although most dogs were younger than 18 months at the date of examination, significantly higher grades of degeneration were detected for the lumbosacral intervertebral disc of German shepherd dogs (P < 0.003). Degeneration of the lumbosacral intervertebral disc was independent from findings in the other lumbar discs. We conclude that the German shepherd dog has a predisposition for degenerative changes in the lumbosacral intervertebral disc.     

残膜积累对土壤理化性状与后茬作物产量影响的研究

本文主要阐述通过小区与中间试验,研究了现推广的覆膜栽培技术。由于残膜积累,土壤理化性状低劣,使后茬作物产量下降。为减少地膜污染,建议采用膜外侧栽培。     

The microbial formation of the 23-keto derivative from avermectin B2a in soil

The nematicide avermectin B_2a, as the [5-³H]-labelled compound, formulated on attapulgite clay and mixed into pots of moist soil, had a half-life of between 2.5 and 3 days in sandy loam soil under greenhouse conditions. A major metabolite, the 23-keto derivative, was identified and shown to be much more persistent than the parent compound. This metabolite is responsible for the prolonged nematicidal activity of avermectin B_2a applied to soil.