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21.
Spatial Variability of Turbulent Mixing in the Abyssal Ocean 总被引:3,自引:0,他引:3
Ocean microstructure data show that turbulent mixing in the deep Brazil Basin of the South Atlantic Ocean is weak at all depths above smooth abyssal plains and the South American Continental Rise. The diapycnal diffusivity there was estimated to be less than or approximately equal to 0.1 x 10(-4) meters squared per second. In contrast, mixing rates are large throughout the water column above the rough Mid-Atlantic Ridge, and the diffusivity deduced for the bottom-most 150 meters exceeds 5 x 10(-4) meters squared per second. Such patterns in vertical mixing imply that abyssal circulations have complex spatial structures that are linked to the underlying bathymetry. 相似文献
22.
Effects of three forage harvesting regimes-total removal of foliage and branches once (T-12) or twice a year (T-6) and 50% removal every 2 months (P-2)-on growth and biological dinitrogen fixation of Gliricidia sepium (Jacq.) Walp were studied under subhumid tropical conditions in Guadeloupe, French Antilles. Gliricidia sepium was grown in association with the perennial C(4) grass Dichantium aristatum (Poir) C.E. Hubbard in a two-storied fodder production system. The medium-term effects of pruning on N(2) fixation were assessed by the (15)N natural abundance method. Gmelina arborea Roxb. was used as the non-fixing reference. The trees in the T-12 regime followed the natural phenological cycle, and flowering and podfilling at the beginning of the dry season reduced both foliage and nodule biomass. The T-6 regime impeded flowering, and only a few flowers, on older branches, were produced in the P-2 regime. In trees in the T-12, T-6, and P-2 regimes, fixed N comprised 54-87, 54-92, and 60-87%, respectively, of the total N in aboveground biomass, depending on sampling date. Total annual accumulation of N in harvestable aboveground biomass was highest in trees in the T-6 regime at 313 kg ha(-1), of which 204 kg ha(-1) of N was fixed from the atmosphere. In all treatments, about 70% of the N exported per year from the plot in the fodder harvest came from N(2) fixation. Thus, N(2) fixation makes an important contribution to the N economy of the G. sepium-D. aristatum forage production system, and greatly reduces the need for fertilizer application. 相似文献
23.
Effect of increasing docosahexaenoic acid content in weaning diets on survival,growth and skeletal anomalies of longfin yellowtail (Seriola rivoliana,Valenciennes 1833) 下载免费PDF全文
Antonio Mesa‐Rodriguez Carmen Maria Hernández‐Cruz Mónica Beatriz Betancor Hipólito Fernández‐Palacios Marisol S Izquierdo Javier Roo 《Aquaculture Research》2018,49(3):1200-1209
Five isoproteic (54.8%) and isolipidic (24.1%) microdiets, which varied in their docosahexaenoic acid (DHA) content (0.25%, 0.75%, 1.64%, 1.99% and 3.17%; dw), were manufactured to determine its effects on longfin yellowtail Seriola rivoliana larvae in terms of fish biological performance, whole body fatty acid profile and incidence of skeletal anomalies from 30 dah (11.31 ± 1.79 Total Length, TL) to 50 dah (19.80 ± 0.58 mm TL). The inclusion of dietary DHA up to 3.17% (dw) improved larval resistance to air exposure, although DHA did not significantly affect fish final growth or final survival. Indeed, high levels of dietary DHA (1.99% and 3.17%, dw) tended to increase the incidence of skeletal anomalies in S. rivoliana larvae, albeit no significant differences were observed. Furthermore, the occurrence of severe anomalies such as kyphosis and lordosis, was mainly associated to the larvae fed the highest levels of dietary DHA. In terms of survival, increasing dietary DHA levels did not significantly affect longfin yellowtail survival rate, despite a tendency for enhanced survival. The results of the present study proved that the inclusion of dietary DHA in inert diets up to a 3.17% (dw) and a DHA/EPA ratio above 3.1 increased the final survival and stress resistance in S. rivoliana larvae. 相似文献
24.
Castro Liliane Araújo Andrade-Porto Sanny Maria Oliveira Rebeca Guimarães Batista Yasmin Luzeiro Silva Felipe Moura Araújo Oliveira Christiane Patrícia Feitosa Affonso Elizabeth Gusmão Cruz Claudinei Tavares-Dias Marcos 《Aquaculture International》2021,29(6):2477-2488
Aquaculture International - This study investigated the efficacy of trichlorfon against Neoechinorhynchus buttnerae, as well as its palatability, residue analysis, and the blood parameters of... 相似文献
25.
Abrahamsen B Zhao J Asante CO Cendan CM Marsh S Martinez-Barbera JP Nassar MA Dickenson AH Wood JN 《Science (New York, N.Y.)》2008,321(5889):702-705
Peripheral pain pathways are activated by a range of stimuli. We used diphtheria toxin to kill all mouse postmitotic sensory neurons expressing the sodium channel Nav1.8. Mice showed normal motor activity and low-threshold mechanical and acute noxious heat responses but did not respond to noxious mechanical pressure or cold. They also showed a loss of enhanced pain responses and spontaneous pain behavior upon treatment with inflammatory insults. In contrast, nerve injury led to heightened pain sensitivity to thermal and mechanical stimuli indistinguishable from that seen with normal littermates. Pain behavior correlates well with central input from sensory neurons measured electrophysiologically in vivo. These data demonstrate that Na(v)1.8-expressing neurons are essential for mechanical, cold, and inflammatory pain but not for neuropathic pain or heat sensing. 相似文献
26.
Winemaking waste solids (WS, resulting from red grapes after fermentation and distillation to recover spirits) were subjected to various processing schemes for isolating fractions with antioxidant activity. The liquors entrapped in WS as received were separated by pressing and freeze-dried to yield a fraction with antioxidant activity (measured as DPPH radical scavenging capacity) comparable to those of synthetic antioxidants. A second approach based on the direct processing of raw WS in sulfuric acid medium under fixed operational conditions and further extraction of hydrolysis liquors with ethyl acetate enabled the isolation of a fraction with higher antioxidant ability at an improved yield. The most favorable approach started with a washing stage leading to liquors (which were directly freeze-dried to yield 1.20 g of extract/100 g of oven-dry WS and presented an EC50 of 0.41 g of extract/L) and washed solids, which were dried and subjected to hydrolytic processing (i) with water as a reactive in an autocatalyzed reaction (autohydrolysis) or (ii) with sulfuric acid solutions to give an ethyl acetate-soluble fraction with improved antioxidant properties (EC50 in the range of 0.18-0.40 g/L). Samples from washing liquors and processing of washed solids in aqueous medium were subjected to chromatographic fractionation and analysis to give isolates with remarkable antioxidant activity (with EC50 as low as 0.07 g/L) and to identify their major components. 相似文献
27.
Ana C. Puello‐Cruz Sofía Mezo‐Villalobos Domenico Voltolina 《Journal of the World Aquaculture Society》2013,44(3):447-454
The objective of this research was to culture the calanoid copepod Pseudodiaptomus euryhalinus, Johnson 1939, and the harpacticoid Tisbe monozota, Bowman, 1962, in monospecific and combined cultures (P. euryhalinus : T. monozota at 1:1, 2:1, and 1:2 starting ratios), and to compare the nauplii, copepodite, and adult production. Mean total production ranged from 740.3 ± 137.5 organisms/L (P. euryhalinus) to 884.3 ± 489.7 organisms/L (T. monozota) for monospecific cultures. The 1:1 ratio mixed cultures gave 780.4 ± 155.8 organisms/L, those with the 2:1 and 1:2 P. euryhalinus and T. monozota starting ratios produced 710.1 ± 195.2 and 799.7 ± 232.5 organisms/L, respectively, and there were no significant difference among treatments. All mixed cultures gave significantly lower copepodite productions than the monocultures of each species. In addition, the tendency to a decreased progeny production of the initial females of T. monozota indicates that the outcome of long‐term mixed cultures would production either a high dominance of P. euryhalinus, or monocultures of this species . 相似文献
28.
López-Sanromán FJ Cruz JM Santos M Mazzini RA Tabanera A Tendillo FJ 《American journal of veterinary research》2003,64(4):475-478
OBJECTIVE: To evaluate the local analgesic effect of ketamine in a palmar digital nerve block at the base of the proximal sesamoid (abaxial sesamoid block) in horses. ANIMALS: 36 mature healthy Andalusian horses. PROCEDURE: Horses were randomly assigned to 4 groups of 9 horses each and received an abaxial sesamoid block in a randomly chosen forelimb with 1 of the following: saline (0.9% NaCl) solution, 1% ketamine solution, 2% ketamine solution, or 3% ketamine solution. To determine analgesia, the radiant heat lamp-hoof withdrawal model was used as a noxious thermal stimulus. Before each nerve block, baseline hoof withdrawal reflex latency (HWRL, time between lamp illumination and withdrawal of the hoof) was determined; after the nerve block, local analgesic effects were determined by measuring HWRL at 2 and 5 minutes after injection and then every 5 minutes for a total period of 1 hour. RESULTS: Significant differences in HWRL were found between baseline values and values at 2 to 15 minutes following a nerve block with ketamine. Significant differences were found between HWRL values at every time point from 2 to 10 minutes following a nerve block with saline solution, compared with 1 or 2% ketamine solution. Similarly, significant differences were found between HWRL values at every time point from 2 to 15 minutes following a nerve block with saline solution, compared with 3% ketamine solution. CONCLUSIONS AND CLINICAL RELEVANCE: Abaxial sesamoid block with ketamine ensures adequate analgesia in horses with an onset of action of 2 minutes and a maximal duration of action of 15 minutes. 相似文献
29.
Dittmar de la Cruz K Ribbeck R Daugschies A 《Berliner und Münchener tier?rztliche Wochenschrift》2003,116(1-2):45-49
During several excavations of archeological sites in the Moquegua Valley, Southern Peru, various guinea pig mummies (Cavia aperea f. porcellus) have been discovered. They belong to the Chiribaya Culture (900-1100 AD). The outstanding preservation of the mummified animals gave rise to the idea of a paleoparasitological analysis. In the fur, numerous well preserved ectoparasites (lice, fleas, mites) could be recovered. Generally, ectoparasite remains are rarely found among archeological material. This is the first account of an extensive ectoparasitological analysis of animal mummies in Peru. A modified technique for recovery and preservation of the ectoparasites has been developed. 相似文献
30.