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Selected AbstractsForegut ossicles morphology and feeding of the freshwater anomuran crab Aegla uruguayana (Decapoda, Aeglidae)ACTA ZOOLOGICA, Issue 4 2010Veronica Williner Abstract Williner, V. 2009. Foregut ossicles morphology and feeding of the freshwater anomuran crab Aegla uruguayana (Decapoda, Aeglidae). ,Acta Zoologica (Stockholm) 91: 408,415. The acquisition and processing of food is critical to animal survival and reproductive success. This work describes the foregut ossicles of Aegla uruguayana, which have been proposed to impart trophic characteristics. In addition, stomach contents were analysed using Index of Relative Importance and Weighted Result Index to characterize the diet. The Pearre index was applied to analyse trophic selectivity. We found A. uruguayana has a morphological foregut typical of macrophage organisms. Stomach contents included items typical of omnivorous, generalist and opportunistic feeding modes. Vegetal remains included algae (filamentous, unicellular and colonial morphotypes), insect larvae, oligochaetes, microcrustaceans (copepods and cladocerans), mites, tardigrades, juveniles of A. uruguayana and rotifers. Morphological descriptions of the foregut can reveal feeding habits and provide data on the possible trophic profile of a species, while guiding the selection of appropriate methodology for subsequent analysis. Our stomach content data corroborated the foregut description, but the presence of small prey suggested A. uruguayana utilizes both predation and detritivory trophic strategies. [source] Estimating fog deposition at a Puerto Rican elfin cloud forest site: comparison of the water budget and eddy covariance methodsHYDROLOGICAL PROCESSES, Issue 13 2006F. Holwerda Abstract The deposition of fog to a wind-exposed 3 m tall Puerto Rican cloud forest at 1010 m elevation was studied using the water budget and eddy covariance methods. Fog deposition was calculated from the water budget as throughfall plus stemflow plus interception loss minus rainfall corrected for wind-induced loss and effect of slope. The eddy covariance method was used to calculate the turbulent liquid cloud water flux from instantaneous turbulent deviations of the surface-normal wind component and cloud liquid water content as measured at 4 m above the forest canopy. Fog deposition rates according to the water budget under rain-free conditions (0·11 ± 0·05 mm h,1) and rainy conditions (0·24 ± 0·13 mm h,1) were about three to six times the eddy-covariance-based estimate (0·04 ± 0·002 mm h,1). Under rain-free conditions, water-budget-based fog deposition rates were positively correlated with horizontal fluxes of liquid cloud water (as calculated from wind speed and liquid water content data). Under rainy conditions, the correlation became very poor, presumably because of errors in the corrected rainfall amounts and very high spatial variability in throughfall. It was demonstrated that the turbulent liquid cloud water fluxes as measured at 4 m above the forest could be only ,40% of the fluxes at the canopy level itself due to condensation of moisture in air moving upslope. Other factors, which may have contributed to the discrepancy in results obtained with the two methods, were related to effects of footprint mismatch and methodological problems with rainfall measurements under the prevailing windy conditions. Best estimates of annual fog deposition amounted to ,770 mm year,1 for the summit cloud forest just below the ridge top (according to the water budget method) and ,785 mm year,1 for the cloud forest on the lower windward slope (using the eddy-covariance-based deposition rate corrected for estimated vertical flux divergence). Copyright © 2006 John Wiley & Sons, Ltd. [source] Physicochemical properties and application of pullulan edible films and coatings in fruit preservationJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 10 2001Tony Diab Abstract The effects of water, sorbitol and a sucrose fatty acid ester (SE) on the water sorption behaviour and thermal and mechanical properties of pullulan-based edible films as well as the physiological responses of fruit coated with pullulan have been studied. Incorporation of sorbitol or SE in pullulan films resulted in lower equilibrium moisture contents at low to intermediate water activities (aw), but much higher moisture contents at aw,>,0.75; estimates of monolayer values (within 4.1,5.9,gH2O,kg,1 solids) were given by application of the Brunauer,Emmett,Teller (BET) and Guggenheim,Anderson,DeBoer (GAB) models. A single glass,rubber transition (Tg), attributed to the polysaccharide component, was detected by calorimetry and dynamic mechanical thermal analysis (DMTA) at a sorbitol level of 15,30% DM. With both tests the strong plasticising action of water and polyol was evident in the thermal curves, and the Tg vs moisture content data were successfully fitted to the Gordon,Taylor empirical model. Multifrequency DMTA measurements provided estimates for the apparent activation energy of the glass transition in the range of , 300,488,kJ,mol,1. With large-deformation mechanical testing, large decreases in Young's moduli (tensile and three-point bend tests) were observed as a result of water- and/or polyol-mediated glass-to-rubber transition of the polymeric films. In the moisture content range of 2,8%, increases in flexural modulus (E) and maximum stress (,max) with small increases in moisture content were found for films made of pullulan or pullulan mixed with 15% DM sorbitol; a strong softening effect was observed when the water content exceeded this range. Addition of sorbitol increased the water vapour transmission rate of the films, whereas addition of SE had the opposite effect. Application of a pullulan/sorbitol/SE coating on strawberries resulted in large changes in internal fruit atmosphere composition which were beneficial for extending the shelf-life of this fruit; the coated fruit showed much higher levels of CO2, a large reduction in internal O2, better firmness and colour retention and a reduced rate of weight loss. In contrast, similar studies on whole kiwifruits showed increased levels of internal ethylene, which caused acceleration of fruit ripening during storage. © 2001 Society of Chemical Industry [source] Pacific walrus (Odobenus rosmarus divergens): Differential prey digestion and dietMARINE MAMMAL SCIENCE, Issue 4 2009Gay Sheffield Abstract Stomach content data from 798 Pacific walruses (Odobenus rosmarus divergens) collected during 1952,1991 were analyzed using a method that evaluates the stage of digestion of prey remains. Non-molluscan prey taxa were not well represented in previous interpretations of walrus diet due to digestion biases. Stomach contents least affected by digestion (fresh stomachs) contained more prey taxa than stomachs of an unknown or more digested state. Bivalves, gastropods, and polychaete worms were the most frequent prey items in both the Bering and Chukchi seas, although bivalves occurred more frequently in stomachs from the Bering Sea and gastropods occurred more frequently in stomachs from the Chukchi Sea. Male and female walruses consumed essentially the same prey when in the same location. Using only fresh stomachs collected between 1975 and 1985, there was no significant difference between the proportion that contained mostly bivalves and the proportion that contained non-bivalve prey items. Earlier interpretations of a change in walrus diet in this period compared to the prior two decades may have been due to digestion as well as sampling biases. Current climatic changes may affect walrus's access to diverse, productive shallow water feeding areas. [source] Migration of Plasticizer between Bonded Propellant InterfacesPROPELLANTS, EXPLOSIVES, PYROTECHNICS, Issue 1 2003Levi Gottlieb Abstract Plasticizer migration across bonded propellant interfaces during cure has been shown to have a measurable effect on propellant properties compared to each propellant by itself. This shows that the curing period is significant to the migration phenomenon. The plasticizer migration has been shown to have a direct influence on tensile strength for short aging periods up to the point the plasticizer reaches equilibrium. The tensile data for short aging periods have been shown to follow an empirical equation connecting the physical characteristics of plasticizer migration with increasing propellant tensile strength. The diffusion coefficient has been evaluated on the basis of this relation from a plot of , versus t1/2 and was in good agreement with the diffusion coefficient from the plasticizer content data. [source] Gut content analysis and a new feeding group classification of termitesECOLOGICAL ENTOMOLOGY, Issue 4 2001S. E. Donovan Summary 1. Gut content analysis of termites was undertaken using microscopical techniques. The 46 study species covered the entire range of taxonomic and feeding forms within the Order. 2. Inter-specific gut contents data were analysed using principal components analysis, placing species along a clear humification gradient based on variations in the amount of silica and plant tissue fragments in the gut. 3. Redundancy analysis was used to find morphological correlates of the observed variation in gut contents. A total of 22 morphological characters (out of 45 candidate characters) were correlated significantly with the gut contents. 4. Three of the 22 significantly correlated characters unambiguously defined feeding groups, which were designated groups I to IV in increasing order of humification of the feeding substrate. Group I contains lower termite dead wood and grass-feeders; group II contains Termitidae with a range of feeding habits including dead wood, grass, leaf litter, and micro-epiphytes; group III contains Termitidae feeding in the organic rich upper layers of the soil; group IV contains the true soil-feeders (again all Termitidae), ingesting apparently mineral soil. These groupings were generally supported statistically in a canonical covariance analysis, although group II apparently represents termite species with a rather wide range of feeding habits. 5. Using existing hypotheses of termite phylogenetic relationships, it seems probable that group I feeders are phylogenetically basal, and that the other groupings have arisen independently on a number of occasions. Soil-feeding (i.e. group III and group IV feeding) may have evolved due to the co-option of faecal material as a fungal substrate by Macrotermitinae-like ancestral forms. As a consequence, these forms would have been constrained to build nest structures from soil and would therefore have passed at least some soil through their guts. [source] | |||||||||||||