The behaviour of the measure of surround in relation to the diameter and spatial structure of a forest stand

Forestry inventory practices have, in the past, concentrated on obtaining information primarily required for timber management. To assess the ecological impact of exploitation, particularly under continuous cover forest management, diversity measures are required that consider the structural diversity in a forest stand. The measure of surround that was initially developed in Germany may be used to quantify the spatial interspersion of different tree size classes as a measure of spatial diversity. While the measure of surround has been applied to practical problems in the past, little is known about its actual performance in relation to stand compositions. This study investigate the behaviour of the index using a number of simulated age class distributions under various degrees of interspersion to provide a norm against which it may be compared. The measure of surround applied to diameter distributions is closely related to the diameter structure of a stand. When diameter classes are interspersed completely randomly within a stand the relative cumulative frequency of the diameter class provides an estimator of the size specific measure of surround. This provides a baseline from which the index may be interpreted.     

An Assessment of Bacterial Populations in a Static Windrow Compost Pile

ABSTRACT

Many companies, restaurants, colleges, as well as individual homeowners, have initiated green marketing campaigns, and the composting of food and yard wastes has become commonplace. Thus, it is essential to obtain a more complete understanding of the microbial populations present in such composting processes. The focus of this study was to identify bacterial populations in a static windrow compost pile initiated on a college campus containing food trim and tree debris. Given that the compost pile was initiated during the winter it was uniquely characterized by a pre-mesophilic stage in addition to the characteristic mesophilic, thermophilic, and cooling/maturation stages. Bacteria were cultured from each stage and were identified by sequencing the 16S rRNA gene. Dominating the numbers throughout the study were bacteria within the Bacillus and Bacillus-like genera. Actinobacteria were found primarily within the pre-mesophilic stage. The mesophilic and beginning thermophilic stages displayed the most diversity, characterized by several different genera within the Proteobacteria phylum. In contrast, during the late thermophilic stage, only bacteria within the Bacillus and Brevibacillus genera were cultured. Overall, 49 different species within 27 different genera, 13 families, and 4 phyla, were identified and several genera that have not been commonly associated with household compost. Thus, this study supports a role for the continuation of culture-dependent studies to more completely define the bacterial flora involved in various composting processes.     

Quantitation of the main constituents of some authentic sesame seed oils of different origin

This paper describes the composition of sesame seed oils obtained from seeds collected from five countries that are major suppliers of traded sesame seed oil. Oils were extracted from the seeds using small-scale industry pressing equipment and analyzed using standard methods for fatty acids, fatty acids in the triglyceride 2-position, tocopherols and tocotrienols, triglycerides, sterols, steradienes, and iodine value. Values for the composition of the sterols, triglycerides, fatty acids, iodine value, and tocopherol composition were generally in good agreement with the results published elsewhere. All of the oils from roasted seeds contained low levels of the sterol degradation products stigmasta-3,5-diene and campesta-3,5-diene, which were probably formed by dehydration of the parent sterols during roasting.     

Mycotoxins and other secondary metabolites produced in vitro by Penicillium paneum Frisvad and Penicillium roqueforti Thom isolated from baled grass silage in Ireland

Secondary metabolites produced by Penicillium paneum and Penicillium roqueforti from baled grass silage were analyzed. A total of 157 isolates were investigated, comprising 78 P. paneum and 79 P. roqueforti isolates randomly selected from more than 900 colonies cultured from bales. The findings mostly agreed with the literature, although some metabolites were not consistently produced by either fungus. Roquefortine C, marcfortine A, and andrastin A were consistently produced, whereas PR toxin and patulin were not. Five silage samples were screened for fungal metabolites, with two visually moldy samples containing up to 20 mg/kg of roquefortine C, mycophenolic acid, and andrastin A along with minor quantities (0.1-5 mg/kg) of roquefortines A, B, and D, festuclavine, marcfortine A, and agroclavine. Three visually nonmoldy samples contained low amounts of mycophenolic acid and andrastin A. The ability of both molds to produce a diverse range of secondary metabolites in vitro and in silage should be a concern to livestock producers.     

Effect of varying the nitrogen and sulfur supply on the flowering of poinsettia 1

Cuttings of poinsettia (Euphorbia pulchemma Willd. ex Klotzsch ‘Dark Red Annette Hegg') were grown hydroponically to flowering at three levels of nitrogen (N) [64,128 or 256 ppm] in combination with five levels of sulfur (S) [0, 8, 16, 32, or 64 ppm]. Plants were kept vegetative for three weeks and then induced to flower using short days. Plants were observed weekly for formation of red bracts and cyathia. Leaves and roots were sampled for N and S content determination every four weeks. Treatments receiving no S showed typical foliage S‐deficiency symptoms, flowered later and less completely, weighed less and were shorter than plants growing in treatments containing S. In terms of plant height and dry weight, there were no differences between treatments containing 128 or 256 ppm N. Leaf S content decreased over time, especially by the end of the experiment, at which time leaf N content had also decreased. This indicates that less fertilizer is needed once flowers approach anthesis. Root S decreased over time and showed an interaction between N and S. Overall, the N and S combinations that should be used in future investigations, since they produced plants of commercially saleable quality and had adequate levels of N and S in most plant parts, were 128 ppm N in combination with 16, 32, or 64 ppm S, and 256 ppm N in combination with 8,16,32, or 64 ppm S.     

Characterization of phytase activity from cultivated edible mushrooms and their production substrates

Phytase is used commercially to maximize phytic acid degradation and to decrease phosphorus levels in poultry and swine manure. To determine phytase content in edible mushrooms, basidiomata of Agaricus bisporus and three specialty mushrooms (Grifola frondosa, Lentinula edodes, and Pleurotus cornucopiae) and spent mushroom substrate (SMS) were surveyed. Enzyme activity ranged from 0.046 to 0.074 unit/g of tissue for four A. bisporus types (closed and open whites and closed and open browns) grown at The Pennsylvania State University's Mushroom Test Demonstration Facility (MTDF). The addition of various nutrient supplements to phase II mushroom production substrate did not alter phytase activity in A. bisporus. Portabella mushrooms (open brown) obtained from a commercial farm had significantly higher levels of phytase activity (0.211 unit/g of tissue) compared to A. bisporus grown at the MTDF. Of the specialty mushrooms surveyed, maitake (G. frondosa) had 20% higher phytase activity (0.287 unit/g of tissue) than commercial portabella mushrooms. The yellow oyster mushroom (P. cornucopiae) ranked second in level of phytase activity (0.213 unit/g of tissue). Shiitake (L. edodes) contained the least amount of phytase in basidiomata (0.107 unit/g of tissue). Post-crop steam treatment (60 degrees C, 24 h) of SMS reduced phytase activity from 0.074 to 0.018 unit/g. Phytase was partially purified from commercially grown portabella basidiomata 314-fold with an estimated molecular mass of 531 kDa by gel filtration chromatography. The optimum pH for activity was 5.5, but appreciable phytase activity was observed over the range of pH 5.0-8.0. Partially purified A. bisporus phytase was inactivated following a 10-min incubation at > or =60 degrees C.     

Effect of processing on the displacement of whey proteins: applying the orogenic model to a real system

Atomic force microscopy (AFM) has been used to investigate the displacement of a commercial whey protein system and the behavior as compared to that of beta-lactoglobulin (Mackie, A. R.; Gunning, A. P.; Wilde, P. J.; Morris, V. J. Orogenic displacement of protein from the air-water interface by competitive adsorption. J. Colloid Interface Sci. 1999, 210, 157-166). The whey protein isolate (WPI) was displaced from an air-water interface by the surfactants Tween 20 and Tween 60. Displacement data obtained were compared with data obtained for pure beta-lactoglobulin and have shown that WPI was more resistant to displacement from the air-water interface than native beta-lactoglobulin. This was related to the greater surface elasticity of WPI at higher surface stresses. In the presence of Tween 20, WPI was observed to remain on the interface at surface pressures up to 8 mN/m greater than the surface pressure at which complete displacement of beta-lactoglobulin was observed. Displacement of WPI and beta-lactoglobulin films by the surfactant Tween 60 showed similar results. However, because of the lower surface activity of Tween 60, it was not possible to reach surface tension values similar to those obtained for Tween 20. Despite the lower surface activity of Tween 60, WPI was still observed to be present at the interface at surface pressure values greater than those by which beta-lactoglobulin had been completely displaced.     

Cast production and NIR spectral signatures of Aporrectodea caliginosa fed soil with different amounts of half-decomposed Populus nigra litter

Sub-adult individuals of Aporrectodea caliginosa were incubated for 16 weeks under laboratory cultures in a soil treated with 0%, 10% or 50% of a Populus nigra half-decomposed leaves, respectively. Growth was maximum in the 50% organic matter treatment and cocoon production occurred. Average soil ingestion rates decreased from 1.56 g/g^?1 fresh weight of worm per day^?1 in control soil to 1.17 and 0.5 g, respectively, in treatments with 10% and 50% half-decomposed litter. Surface casts never comprised more than 10% of total cast production. Near-infrared spectrometry (NIRS)signatures of digested and non-ingested soil significantly differed and showed a rather constant effect of digestion, independent of the organic matter content (p?<?0.01). These results confirm the value of NIRS spectral signatures as indicators of the origin of soil aggregates and biological processes involved in soil aggregation.     

Anaerobic Bioremediation of a Soil With Mixed Contaminants: Explosives Degradation and Influence on Heavy Metal Distribution,Monitored as Changes in Concentration and Toxicity

Water, Air, & Soil Pollution - The sorption behavior of bisphenol A (BPA) on marine sediments treated using different methods was investigated in batch equilibrium experiments. Adsorption...     

Monitoring Acid Waters in the UK: 1988–1998 Trends

Since 1988, a network of lakes and streams has been monitored in areas of the UK sensitive to surface water acidification. Analysis of 10 years data has focused on the identification and quantification of time-trends in chemical parameters, to establish whether declines in emission of acidifying pollutants have resulted in recovery of acidified surface waters. A national decline in S deposition in the UK since 1988 has not generally been accompanied by a significant improvement in freshwater chemistry. At the three sites where xSO₄ concentrations have declined, NO₃ has increased and there has been no increase in pH or alkalinity. Upward trends in pH and alkalinity observed at several other sites are not associated with downward trends in acidic anions. Temporal variation in xSO₄, NO₃, acidity, DOC and other important meaures of surface water quality can all be linked to decadal-scale variation in climate, and this has important implications for the detection of recovery-related trends.