Proportion Of Structural Components Research Articles

Differences in the Structural Components Influence the Pumping Capacity of Marine Sponges

Marine sponges are important sessile, benthic filter feeders with a body plan designed to pump water efficiently. The sponge body plan generally consists of mineral spicules, gelatinous mesohyl, and the pores and canals of the aquiferous system. These structural components have stark differences in compressibility, mass, and volume; therefore, their proportion and distribution are likely to affect sponge morphology, anatomy, contraction, and finally the pumping capacity. We examined seven demosponge species (from high spicule skeleton contents to no spicules) commonly found along the central west coast of India for structural components, such as total inorganic contents (spicule skeleton and foreign inclusions), body density, porosity, and mesohyl TEM for the high microbial abundance/low microbial abundance status. Additionally, we estimated the sponge pumping rate by measuring the excurrent velocity, the abundance of individual pumping units and cells, i.e., choanocyte chambers and choanocytes, and also carried out a morphometric analysis of aquiferous structures. The excurrent velocity and the oscular flow rates showed a positive relationship with the oscular crosssectional area for all the study species. The inorganic spicule contents by their weight as well as volume formed a major component of tissue density and higher proportions of spicules were associated with reduced aquiferous structures and lower pumping rate. The ash mass% and the ash free dry weight (AFDW %) in the sponge dry mass showed separate and distinct associations with aquiferous system variables. For example, the number of choanocytes per chamber showed a wide difference between the studied species ranging from 35.02 ± 2.44 (C. cf. cavernosa) to 120.35 ± 8.98 (I. fusca) and had a significant positive relationship with AFDW% and a negative relationship with ash mass%. This study indicates that the differences in the proportions of structural components are closely related to sponge gross morphology, anatomy, and probably body contractions, factors that influence the sponge pumping capacity.

BLACK OAT AND RYEGRASS INOCULATED WITH Azospirillum brasilense IN CROP-LIVESTOCK SYSTEM

ABSTRACT The success of the integrated crop-livestock system depends on the correct pasture management, particularly regarding nitrogen fertilization and grazing intensity. The objective of this study was to evaluate the total production of forage and the proportion of the botanical and structural components of black oat and annual ryegrass mixture. The experimental design was randomized blocks with three replicates and the treatments were arranged in a three-factorial scheme: seed inoculation (with and without Azospirillum brasilense inoculation), grazing management (conventional grazing, where the animals were kept in pasture with no control of pasture height; 30, 20 and 10 cm at the end of grazing, and a control without grazing), and nitrogen fertilization (0, 50 and 100 kg nitrogen ha-1). In treatments with pasture heights where grazing ended at 30, 20 and 10 cm, the height was monitored and biomass was collected when the animals entered and exited the plots. Manual separation of the components was used to determine the dry mass of green leaves, stems, senescent material and inflorescence. Total dry mass production was obtained based on the initial forage mass plus the daily accumulation rates. The proportion of structural components varied according to the different grazing managements, nitrogen doses and inoculation with Azospirillum brasilense. Biomass production of black oat and ryegrass mixture was increased by nitrogen application and Azospirillum brasilense inoculation.

Egg quality of Banat naked neck hens during storage

In less intensive production systems, native poultry breeds can be used in order to diversify the products and achieve self-sustainability of these breeds through production. Given the missing data on the sustainability of quality of eggs obtained from indigenous, native hens, during storage, the aim of the study was to determine the most important parameters of egg quality of indigenous breed of Banat Naked Neck hens during a four-week period in different storage conditions. The design of the experiment was two-factorial with 4 levels of storage time factors (fresh eggs - 0, 1, 2, 3 and 4 weeks of storage) and 2 levels of temperature storage condition factors (room temperature and refrigerator). The room temperature was on average 21.3?C and the refrigerator temperature 8?C. Quality analysis was performed on a total of 200 eggs, and it included following parameters: egg weight, egg weight loss, weight and proportion of structural components: shell, yolk and albumen, albumen height, yolk colour, Haugh Units and albumen pH. The storage time had a significant effect on all properties of egg quality, except for the yolk colour, which was under the impact of the interaction of storage time and temperature. Storage temperature influenced egg weight loss (<0.001), shell weight (<0.05), albumen height (<0.0001), Haugh Units (<0.0001) and albumen pH (<0.0001). By storing in the refrigerator, changes in internal quality were significantly slowed down. After 28 days of storage in the refrigerator, the values of albumen and Haugh Units were higher than the same parameters of eggs stored for only 7 days at room temperature.

Sheep-Grazing with Different Foraging Efficiences in a Dutch Mixed Grassland

(1) In 1972, 11 ha of woodland, heathland and previously manured pasture was fenced in for a sheep-grazing experiment. The different grazing intensities in the grassland area were quantified, since it is considered a prerequisite for the establishment of heterogeneous vegetation patterns, i.e. closely grazed areas, roughness and shrub. (2) Grazing intensity, implying associated effects of treading and dunging (occupancy), can be estimated by dunging intensity. Grazing intensity implying the defoliation by animals can be estimated using exclusion cages. Despite the fact that both methods show a degree of inaccurancy they seem appropriate for nature conservation purposes. (3) Peak standing crop (including standing dead material, but excluding litter) reached 210 g m-2 in Leontodon autumnalis, 420 g m-2 in Holcus lanatus, 510 g m-2 in Agrostis capillaris, 730 g m-2 in Agrostis stolonifera, 830 g m-2 in Juncus acutiflorus, and 1130 g m-1 in Juncus effusus communities in October 1981. (4) Grazing intensity expressed as efficiency of foraging was 0.89 in Leontodon autumnalis, 0.30 in Holcus lanatus and 0-09 in Agrostis capillaris communities over a 6 month period from June to November 1981. (5) Low species diversity was related to very low efficiency of foraging, whereas species diversity was relatively high for foraging efficiencies ranging from moderate to high. (6) Grazing at an average stocking of 3 sheep ha-' resulted in a smaller area (13%) with a short turf ( 36 cm), and a much larger area (69%) with intermediate turf. (7) Measurements of foraging efficiency can enhance the ideal situation in which authorities in charge of management, knowing the herbage accumulation, could indicate preferred proportion of structural components and then determine the appropriate stocking density.