Landscape,Soil, and Plant Analysis of Japanese Stiltgrass (Microstegium vimineum) Invasion in the Piedmont Region,SC

Japanese stiltgrass (Microstegium vimineum), an exotic invasive plant, is native to Southeast Asia. This study was conducted to determine the chemical composition of Japanese stiltgrass as well as soil and landscape characteristics that correlate with invasion of Japanese stiltgrass around Lake Issaqueena in the upper Piedmont of South Carolina. Geographic Information Systems (GISs) and Light Detection and Ranging (LiDAR) were used to determine the spatial pattern of invasion with respect to the aspect, slope, canopy cover, soils, and distance to roads and trails. Japanese stiltgrass was distributed on both sides of Lake Issaqueena in Pacolet and Madison soil map units (Fine, kaolinitic, thermic Typic Kanhapludults) on the average slopes of 21%, but it was particularly common on the eastern shore of the lake in low-lying wet and shaded areas (mean canopy cover 51%). In addition, invasion by Japanese stiltgrass was correlated with the proximity to roads and trails. Plant tissue analysis revealed many differences in the distribution of macronutrients, macrominerals, and micronutrients in the leaves, stems, and roots of Japanese stiltgrass, although those differences were not always statistically significant. Concentrations of nitrogen (N), phosphorus (P), and calcium (Ca) were the highest in leaves while zinc (Zn) concentrations were the highest in stems and concentrations of magnesium (Mg), copper (Cu), manganese (Mn), iron (Fe), and sodium (Na) tended to be higher in roots. Carbon (C), sulfur (S), and potassium (K) concentrations were generally higher in above-ground tissues versus roots. Soil chemical analysis revealed no statistical differences between control and invaded plots. Our findings suggest that watershed areas surrounding lakes may be particularly susceptible to the invasion of Japanese stiltgrass due to their microclimates, low-lying wet pathways for seed distribution and recreational uses.     

Properties of low-moisture viscoplastic materials consisting of oil droplets dispersed in a protein-carbohydrate-glycerol matrix: effect of oil concentration

The influence of oil concentration and baking on the properties of low-moisture composites consisting of oil droplets dispersed in a protein-carbohydrate-glycerol matrix was investigated. These composites were produced by blending canola oil, whey protein concentrate (WPC), corn syrup, and glycerol together using a high-speed mixer. The resulting system consisted of oil droplets dispersed in a polar matrix. Some composites were analyzed directly after preparation, while others were analyzed after being heated at 176 degrees C for 10 min to simulate baking. The "lightness" of the composites was greater before baking (higher L value), but the color was more intense after baking (higher a and b values). The lightness and color intensity of the composites decreased as the oil concentration increased, with the effects being more pronounced in the baked samples. The zeta potential of the oil droplets (measured after dilution at pH 6) was highly negative (approximately -40 mV), indicating that whey protein was adsorbed to the droplet surfaces. The mean particle diameter (measured after dilution at pH 6) increased appreciably after baking, which was attributed to droplet flocculation. The rheological properties of the unbaked and baked materials were characterized by squeezing flow viscometry, which showed that the measurements associated with consistency and yield stress increased with increasing oil concentration and with baking.     

Genetic analysis of resistance to spot blotch disease in wheat (Triticum aestivum L.) in Zambia

Understanding the genetics of resistance to spot blotch disease, caused by Bipolaris sorokiniana (Sacc.) Shoem, is important to design an appropriate breeding strategy to improve the trait. The objective of this study was to determine the gene action and mode of inheritance of resistance to spot blotch in wheat. Eight genotypes with varying resistance to the disease were crossed in a full diallel mating design. Parents and their progenies were evaluated for spot blotch resistance. Data were analyzed using Hayman’s diallel analysis. The results suggested the importance of additive gene effects in controlling the resistance to spot blotch in the materials under study. No epistasis, maternal, or reciprocal effects were detected. Resistance to spot blotch exhibited partial dominance. Therefore, exercising selection for resistance in the early segregating generation should be an effective approach because of the predominance of additive gene effects. The Wr/Vr graph showed that the parents 30SAWSN5 (P3) and Coucal (P4) possessed more dominant genes, which makes them particularly suitable for inclusion in breeding for resistance to spot blotch.     

Spatial variability of organic matter degradability in tidal Elbe sediments

Purpose

The microbial turnover of sediment organic matter (OM) in ports and waterways impacts water quality, sonic depth finding and presumably also rheological properties as well as greenhouse gas emissions, especially if organic carbon is released as methane. As a consequence, sediment management practices as a whole are affected. This study aimed to discern spatial OM degradability patterns in the Port of Hamburg and investigated correlations with standard analytical properties as a basis for future predictive modelling.

Materials and methods

Sediments in the Port of Hamburg were repeatedly sampled at nine locations along an east-west transect using a 1-m corer. In a stratified sampling approach, layers of suspended particulate matter (SPM), fluid mud (FM), pre-consolidated sediment (PS) and consolidated sediment (CS) were identified and individually analysed for long-term aerobic and anaerobic degradation of organic matter, DNA concentration, stable carbon isotope signature, density fractions and standard solids and pore water properties.

Results and discussion

The investigation area was characterised by a distinct gradient with a 10-fold higher OM degradability in upstream areas and lower degradability in downstream areas. Concomitantly, upstream locations showed higher DNA concentrations and more negative δ¹³C values. The share of bulk sediment in the heavy density fraction as well as the proportion and absolute amount of organic carbon were significantly larger at downstream locations. A depth and hence age-related gradient was found at individual locations, showing higher degradability of the upper, younger material, concomitant with higher DNA concentration, and lower OM turnover in the deeper, older and more consolidated material. Deeper layers were also characterised by higher concentrations of pore water ammonium, indicative of anaerobic nitrogen mineralisation.

Conclusions

Organic matter lability is inversely linked to its stabilisation in organo-mineral complexes. The observed degradability gradient is likely due to the different OM quality in relation to its origin. Downstream OM enters the system with the tidal flood current from the direction of the North Sea whereas upstream locations receive OM originating from the catchment, containing more autochthonous, plankton-derived and more easily degradable components. At individual sampling points, depth-related degradability gradients reflect an age gradient, with easily degradable material in top layers and increasing stabilisation of OM in organo-mineral compounds with depth.

     

Dwarf shrub litter as a food source for macro-decomposers in alpine pastureland

Dwarf shrub litter is thought to be of poor quality and palatability for macro-decomposers. In laboratory feeding experiments, however, it was found that this litter type represents a potential food source for earthworms and millipedes. Here we tested whether this is true under natural conditions by conducting a 1 year field experiment on an abandoned alpine pasture in Tyrol (Austria). As the natural isotopic signatures of plant litter do not allow discriminating between different plant species, dwarf shrub litter, artificially enriched in ¹⁵N, was offered in experimental plots to the macro-decomposer community. Both the earthworm Lumbricus rubellus and the millipede Cylindrojulus fulviceps fed on dwarf shrub litter as indicated by their increased δ¹⁵N signatures, but IsoError analysis indicated a clear preference for grass litter for all macro-decomposer species investigated.Soil δ¹⁵N signatures were only marginally affected by the experimental provision of ¹⁵N-enriched dwarf shrub litter, whereas litter from other, unlabelled, plants became enriched by the isotopic tracer to some extent. Except for one grass species, plants harvested at the end of the experiment were not enriched in ¹⁵N, suggesting that the N-uptake from decomposing litter material by plants on abandoned alpine pastureland is slow.     

Trade-offs among establishment success,stem morphology and productivity of underplanted Toona ciliata: Effects of nurse-species and thinning density

Toona ciliata (Australian red cedar), a valuable hardwood species, requires a nurse-tree overstorey to prevent damage from frost and drought in some regions of north-eastern Argentina. Different nurse-species offer different degrees of protection, resource competition, and thinning revenues. In addition, choice of nurse-species will influence trade-offs between T. ciliata establishment success, stem quality and productivity as well as revenue from intermediate and final harvests. We tested the effects of overstorey species and planting density on underplanted T. ciliata survival, stem morphology and growth. Initial stand densities of nurse-species Pinus taeda (625 stems/ha), P. elliottii × P. caribaea (625 stems/ha), and Grevillea robusta (833 stems/ha) were thinned by 0%, 25%, 50%, and 75% in three experiments, each using a randomized block design. Initial mortality, light availability and growth of T. ciliata, as well as growth of its nurse-trees, were measured before and two years after thinning. In the third year, we characterized T. ciliata stem morphology (straightness and height-to-diameter-ratio) and destructively harvested a subsample of T. ciliata in order to investigate T. ciliata biomass production and allocation patterns in response to overstorey species, thinning density and light availability. T. ciliata mortality was lower when planted under G. robusta than the pines, and increased in plots with greater exposure to solar radiation. T. ciliata productivity was also greater under G. robusta than under the pines, and was generally greatest where any of the nurse-species were thinned by 75%. Stem form was best when growing under P. taeda and in stands thinned by 50%, regardless of nurse-species. With the exception of early mortality, light levels appeared to have limited effects on T. ciliata growth dynamics. Neither growth rate nor stem morphology was strongly correlated with light availability. Total overstorey basal-area was highest in P. taeda stands and individual overstorey tree growth generally increased with decreasing stand densities, except for slower height growth of G. robusta in more open stands. Thinning operations resulted in sawn-wood revenue for the pine species only. Because stand productivity and stem quality were optimized under different nurse-species and thinning treatments, we conclude that the choice of nurse-species and thinning intensity will depend on management objectives and will change with market preferences and conditions.     

Treatment of methicillin-resistant Staphylococcus epidermidis infection following repair of an ulnar fracture and humeroradial joint luxation in a horse

A 27-month-old Rocky Mountain Horse was examined because of a fracture of the proximal portion of the ulna and luxation of the humeroradial joint (Monteggia fracture). Open reduction was performed, using a mechanical distractor, and the ulnar fracture was stabilized by application of a bone plate and screws. After surgery, the horse developed an infection of the surgical site, and bacterial culture of fluid from the surgical site yielded a pure growth of methicillin-resistant Staphylococcus epidermidis susceptible to oxytetracycline, erythromycin, rifampin, and vancomycin. Treatment with oxytetracycline did not result in a favorable clinical response. Therefore, the horse was treated systemically with vancomycin and rifampin, and vancomycin-impregnated polymethyl methacrylate beads were implanted at the surgical site. Six months after surgery, the horse was sound at a walk or trot, and bony union was evident on radiographs of the elbow joint.     

Usefulness of aerobic microbial culture and cytologic evaluation of corneal specimens in the diagnosis of infectious ulcerative keratitis in animals

OBJECTIVE: To determine the diagnostic value of aerobic microbial culture and cytologic evaluation of corneal specimens in the diagnosis of infectious ulcerative keratitis (IUK). DESIGN: Prospective study. ANIMALS: 48 animals (26 dogs, 13 horses, 7 cats, 1 bird, and 1 llama) with corneal ulcers. PROCEDURE: Scrapings from corneal ulcers were examined cytologically. Corneal swab specimens were submitted for microbial culture. Animals were grouped according to whether they had been receiving antimicrobials at the time of admission. RESULTS: Of the 38 animals receiving antimicrobials, 19 had positive results for IUK on cytologic evaluation, 20 on microbial culture, and 26 on cytologic evaluation, microbial culture, or both. Of the 10 animals not receiving antimicrobials at the time of admission, 7 had positive results for IUK on cytologic evaluation, and 9 had positive results on microbial culture. In this group of 10 animals, additional animals with IUK were not identified on the basis of cytologic evaluation alone. When all 48 animals were considered irrespective of antimicrobial treatment, 26 and 29 had positive results for IUK on cytologic evaluation and microbial culture, respectively, whereas IUK was confirmed in 35 animals on the basis of cytologic evaluation, microbial culture results, or both. CONCLUSIONS AND CLINICAL RELEVANCE: Microbial culture and cytologic evaluation of corneal specimens maximizes identification of IUK, especially in animals receiving antimicrobial treatment. Because of serious consequences of untreated IUK, we recommend that both diagnostic tests be used to tailor treatment and reduce risk of vision impairment in animals.     

Studies of Coxiella burnetii infections in dairy herds with special regard to infections in men

Investigations of 1167 dairy cows out of 105 herds with fertility disorders on secretion of Coxiella burnetii (C. burnetii) by the genitals as well as serological studies of these animals using ELISA demonstrated that C. burnetii infections are significantly associated with abortions but not with repeated inseminations without success or vaginal excretions. The demonstration of an increased risk of infections for persons caring for those dairy herds could be shown by a total of 253 serological studies. A comparison of these studies of farmers caring for dairy herds suffering from abortions a seroprevalence of > or = 20% showed that these persons revealed significantly more frequent antibodies against C. burnetii than farmers of the group compared with. Further studies showed that in herds suffering from abortions a seroprevalence of > or = 20% means an additional risk of infections of farmers. Vice versa abortions of the cows in herds with a seroprevalence of > or = 20% imply an additional infectious risk.