|
| ||
|
|
||
Acclimation Period (acclimation + period)
Selected AbstractsCold hardiness of diapausing and non-diapausing pupae of the European grapevine moth, Lobesia botranaENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 2 2005Stefanos S. Andreadis Abstract Lobesia botrana (Denis & Schiffermüller) (Lepidoptera: Tortricidae) is a key pest of grapes in Europe. It overwinters as a pupa in the bark crevices of the plant. Supercooling point (SCP) and low temperature survival was investigated in the laboratory and was determined using a cool bath and a 1 °C min,1 cooling rate. Freezing was fatal both to diapausing and non-diapausing pupae. SCP was significantly lower in diapausing male (,24.8 °C) and female (,24.5 °C) pupae than in non-diapausing ones (,22.7 and ,22.5 °C, respectively). Sex had no influence on SCP both for diapausing and non-diapausing pupae. Supercooling was also not affected by acclimation. However, acclimation did improve survival of diapausing pupae at temperatures above the SCP. Survival increased as acclimation period increased and the influence was more profound at the lower temperatures examined. Diapausing pupae could withstand lower temperatures than non-diapausing ones and lethal temperature was significantly lower than for non-diapausing pupae. Freezing injury above the SCP has been well documented for both physiological stages of L. botrana pupae. Our findings suggest a diapause-related cold hardiness for L. botrana and given its cold hardiness ability, winter mortality due to low temperatures is not expected to occur, especially in southern Europe. [source] Nutrient limitations during the biofiltration of methyl isoamyl ketoneENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 1 2005Hyun-Keun Son With biofiltration, both organic and inorganic compounds that are toxic to humans and volatile organic compounds from a variety of industrial and public sector sources have been effectively removed. During the initial stage of the acclimation period, the removal capacity of the biofilter is primarily attributed to the adsorption capacity of the media. The adsorption capacity of different types of biofilter media was studied. MIAK (methyl isoamyl ketone), which is one of the major air pollutants in painting operations, was used as the target air pollutant for the biofiltration experiments. All the materials tested exhibited very poor adsorption capacity for MIAK. The effect of nutrient limitation was also evaluated. A gradual decrease of removal capacity was observed under the nutrient-limited environment. When nutrient was provided to the biofilter, the removal capacity increased from 55 to 93% in 3 days. A nutrient ratio of chemical oxygen demand (COD):N:P = 200:4:1 was sufficient for the removal of volatile organic compounds from the polluted air stream. © 2004 American Institute of Chemical Engineers Environ Prog, 2004 [source] Experimental and neural model analysis of styrene removal from polluted air in a biofilterJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 7 2009Eldon R. Rene Abstract BACKGROUND: Biofilters are efficient systems for treating malodorous emissions. The mechanism involved during pollutant transfer and subsequent biotransformation within a biofilm is a complex process. The use of artificial neural networks to model the performance of biofilters using easily measurable state variables appears to be an effective alternative to conventional phenomenological modelling. RESULTS: An artificial neural network model was used to predict the extent of styrene removal in a perlite-biofilter inoculated with a mixed microbial culture. After a 43 day biofilter acclimation period, styrene removal experiments were carried out by subjecting the bioreactor to different flow rates (0.15,0.9 m3 h,1) and concentrations (0.5,17.2 g m,3), that correspond to inlet loading rates up to 1390 g m,3 h,1. During the different phases of continuous biofilter operation, greater than 92% styrene removal was achievable for loading rates up to 250 g m,3 h,1. A back propagation neural network algorithm was applied to model and predict the removal efficiency (%) of this process using inlet concentration (g m,3) and unit flow (h,1) as input variables. The data points were divided into training (115 × 3) and testing set (42 × 3). The most reliable condition for the network was selected by a trial and error approach and by estimating the determination coefficient (R2) value (0.98) achieved during prediction of the testing set. CONCLUSION: The results showed that a simple neural network based model with a topology of 2,4,1 was able to efficiently predict the styrene removal performance in the biofilter. Through sensitivity analysis, the most influential input parameter affecting styrene removal was ascertained to be the flow rate. Copyright © 2009 Society of Chemical Industry [source] Anaerobic co-digestion of potato processing wastewater with pig slurry and abattoir wastewaterJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 12 2008Maria Monou Abstract BACKGROUND: Small-scale experimental investigations were carried out on the anaerobic digestion of potato processing wastewater and its co-digestion with pig slurry and/or abattoir wastewater. A simple and rapid procedure was used to determine the suitability of these wastes for digestion. RESULTS: During the initial 5-day acclimation phase, the seed (digested brewery waste) was replaced by the test waste before allowing the tests to incubate without further addition, where methanogenesis was measured. Although potato processing wastewater has low pH, with high fat content treatment via anaerobic digestion was still feasible in spite of low methane production. Co-digestion with pig slurry and abattoir wastewater was therefore investigated to enhance the process. Pig slurry improved the process, which, when co-digested with potato processing wastewater in equal ratio achieved 72% volatile solids removal, 35 mL average daily biogas production and 32% maximum methane content in 22 days (following the acclimation period). Co-digestion with abattoir wastewater did not improve the digestion process due to poor buffering and low pH value. CONCLUSION: Anaerobic co-digestion may be a feasible treatment option for industrial bio-wastes and livestock wastes produced in Cyprus and indeed in similar other countries of comparable market size and activities. Copyright © 2008 Society of Chemical Industry [source] Antarctic fish can survive prolonged exposure to elevated temperaturesJOURNAL OF FISH BIOLOGY, Issue 7 2008E. Robinson The Antarctic notothenioid Pagothenia borchgrevinki was collected from the stenothermal waters of McMurdo Sound in the summers of 2004, 2005 and 2006. Acclimation ability at 4° C was tested in healthy P. borchgrevinki and in individuals infected with x-cell gill disease. All healthy fish successfully acclimated to 4° C, establishing compensatory changes in resting oxygen consumption rate (Rrest) and critical swimming speed (Ucrit) during a 1 month acclimation period, which were maintained during a longer, 6 month acclimation period. In contrast, individuals infected with x-cell disease were unable to acclimate to 4° C, demonstrating significantly reduced survival rates compared with healthy individuals at 4° C. Measurements of Rrest suggest that limitations in the ability of x-cell fish to uptake oxygen from the external milieu may have a negative effect on their survival at 4° C. [source] Acoustic Startle Reactivity During Acute Alcohol Withdrawal in Rats That Differ in Genetic Predisposition Toward Alcohol Drinking: Effect of Stimulus CharacteristicsALCOHOLISM, Issue 5 2004Julia A. Chester Abstract: Background: We have previously reported an association between greater alcohol withdrawal magnitude after a single alcohol exposure and a genetic predisposition toward low alcohol drinking in rats selectively bred for differences in alcohol intake when acoustic startle reactivity to a tone stimulus was used to index acute alcohol withdrawal. The purpose of this study was to examine whether the quality of the acoustic startle stimulus (noise versus tone) is important for detecting a genetic relationship between alcohol withdrawal magnitude and alcohol drinking behavior. Methods: Alcohol-naive male rats selectively bred for high alcohol intake [alcohol-preferring (P), high-alcohol-drinking (HAD)1, and HAD2] or low alcohol intake [alcohol-nonpreferring (NP), low-alcohol-drinking (LAD)1, and LAD2] received a single intragastric infusion of water or alcohol (4.0 g/20.3 ml/kg; 25% v/v), and acoustic startle test sessions were given at 14, 16, 18, 20, and 24 hr after infusion. Each test session consisted of a 5-min acclimation period followed by random presentation of various white noise stimuli (90, 100, 110, and 120 dB.) Results: Line differences in acoustic startle magnitude under control conditions were present in all three pairs of selectively bred lines; P rats showed a greater startle magnitude relative to NP rats, whereas both LAD lines showed a greater startle magnitude relative to both HAD lines. During alcohol withdrawal, the P, HAD1, and HAD2 lines showed enhanced startle magnitude compared with their water-treated controls. No change in startle magnitude during alcohol withdrawal was found in the NP, LAD1, or LAD2 lines. Conclusions: In contrast to our prior findings, these results showed a genetic association between high alcohol drinking and a greater startle response magnitude to a noise stimulus during alcohol withdrawal. It seems that the genetic association between alcohol drinking and alcohol withdrawal, as assessed by the acoustic startle response, depends on the quality of the acoustic startle stimulus. [source] Effects of radio-collars on European badgers (Meles meles)JOURNAL OF ZOOLOGY, Issue 1 2002F. A. M. Tuyttens Abstract The relationships between radio-collaring/tracking and 12 biometric parameters in a population of badgers (Meles meles) that were live-trapped in south-west England were investigated. The length of time for which a badger had worn a radio-collar was selected as an explanatory variable in generalized linear models of three biometric parameters (body condition, body weight and testes volume) irrespective of whether or not age class was included as a variable in the analyses. There was evidence that badgers that had been carrying a radio-collar for 1,100 days had lower body condition scores both when compared to badgers that had not been collared and with those that had been collared for longer than 100 days, suggesting a post-collaring acclimation period. In addition, the time period between first and last capture was longer for radio-collared than non-collared badgers. It is unlikely that this was due to an effect of collaring on trappability or to non-random selection of badgers for collaring. Although testes size differed between non-collared badgers and badgers that had been tagged for > 100 days, the relationship between radio-collaring and reproductive output remained unproven. These results highlight not only the need to assess the welfare aspects of radio-collaring but also the potential intricacy of corollaries of collaring. Explorations such as that reported here are important to the validity of studies that make use of radio-telemetry. [source] Effects of extrusion processing of feed ingredients on apparent digestibility coefficients of nutrients for rainbow trout (Oncorhynchus mykiss)AQUACULTURE NUTRITION, Issue 2 2003Zongjia J. Cheng Abstract An experiment was conducted to evaluate the effects of extrusion processing on apparent digestibility coefficients (ADCs) of dry matter, crude protein, crude fat, energy and minerals in soya bean meal (SBM), barley, corn gluten meal and whole wheat, using rainbow trout Oncorhynchus mykiss as the test species. In addition, availabilities of amino acids were also determined in SBM. Feed ingredients were preconditioned at 89,93 °C and then extruded using a Wenger X-85 extruder. Nonextruded ingredients were used as is, meaning that they were not preconditioned. The extruded and nonextruded ingredients were mixed with a casein,gelatin reference diet at 3 : 7 ratio prior to determination of ADC values. A total of 135 trout (initial mean body weight 223.4 ± 12.7 g) were stocked into nine 140-L fibreglass digestibility tanks with 15 fish per tank. Individual tanks were assigned randomly to each of eight diets made from the four ingredients (extruded and nonextruded) plus the reference diet. After faeces were collected in the first week, the diets were switched among tanks, and faeces were collected again after 5-day acclimation period in the second week. Yttrium oxide was used as the inert marker. Results showed that extrusion processing significantly improved ADCs of dry matter, crude fat and gross energy, and reduced ADCs of crude protein, phosphorus, copper, iron and zinc. Results also showed that the effects of extrusion processing on chemical composition and ADCs of nutrients depended on the ingredients. It is recommended that trace minerals such as copper, iron and zinc be supplemented by an additional 10,20% when rainbow trout diets are extruded because of their reduced bioavailability in plant meal-based feed ingredients. [source] Short-term physiological response of the Pacific oyster, Crassostrea gigas, on exposure to varying levels of polycyclic aromatic hydrocarbonAQUACULTURE RESEARCH, Issue 15 2007Mu-Chan Kim Abstract In the present study, we investigate the short-term adaptive physiological strategies to polycyclic aromatic hydrocarbon (PAH) of Pacific oysters, Crassostrea gigas, by exposing the oysters to varying levels of PAH (0, 50, 100 and 200 ,g L,1) for 7 days with a 3-day acclimation period under laboratory conditions. The filtration rate (FR) and respiration rate (R) increased significantly at 50 ,g L,1 PAH and decreased at 100 and 200 ,g L,1 compared with the control. The absorption efficiency (Abs. eff.) was significantly impaired at 200 ,g L,1 PAH. Ammonia excretion (E) increased with increasing PAH levels, with a significant elevation at 200 ,g L,1. Although a significantly elevated FR was observed, oysters exposed to 50 ,g L,1 PAH showed scope for growth (SFG) similar to the control. This indicates that even at nominal levels, PAH contamination is a possible cause of reduced oyster production because of increased food demand. The oysters exposed to 200 ,g L,1 PAH showed negative SFG values, which could be a possible cause of growth stagnation or even mortality when the exposure is chronic. [source] Cold tolerance of the banana prawn Penaeus merguiensis de Man and its growth at different temperaturesAQUACULTURE RESEARCH, Issue 1 2002Tung Hoang Abstract Critical thermal minima (CTMin) were determined for subadults of Penaeus merguiensis acclimated at 15, 18, 21 and 24 °C for 3 weeks. The effect of cooling rate on CTMin was also investigated. The CTMin of prawns from these respective acclimation groups were 5.3, 6.0, 7.4, 9.0 and 4.7, 5.4, 6.0, 7.3 °C at the cooling rate of 1 °C h,1 and 3 °C h,1 respectively. Both acclimation temperature and cooling rate had a significant effect (P < 0.01) on the CTMin. Observation during the acclimation period showed that the growth rate of prawns acclimated at 24 °C was much higher than those acclimated at 21, 18 and 15 °C. The results indicate that P. merguiensis can overwinter in aquaculture ponds in south-east Queensland, Australia, or other subtropical areas and attain good growth if simple overwintering facilities are available. [source] Growth and performance of the whiteleg shrimp Penaeus vannamei (Boone) cultured in low-salinity water with different stocking densities and acclimation timesAQUACULTURE RESEARCH, Issue 6 2010Héctor M Esparza-Leal Abstract We evaluated the performance of whiteleg shrimp Penaeus vannamei (Boone, 1931) in response to different stocking densities and acclimation periods. Shrimp postlarvae were acclimated from seawater (30 g L,1) to low-salinity well water (<1.0 g L,1) at a constant hourly reduction rate of 40, 60, 80 and 100 h. After acclimation to low-salinity well water, postlarvae from each acclimation time treatment were stocked in three replicate tanks at densities of 50, 100, 150 or 200 shrimps m,2 for 12 weeks of growth. Salinity averaged <1.0 g L,1 for each growth study. The different treatments resulted in significant differences in both the final body weight and the survival rate (SR). Shrimp acclimated for 100 h showed substantially improved survival (83%) relative to shrimp acclimated for shorter periods. Shrimp yields for all cultured periods ranged from 0.32 kg m,2 in tanks stocked at 50 m,2 to 1.14 kg m,2 in tanks stocked at 200 m,2. We conclude that whiteleg shrimp can be successfully grown in low-salinity well water, and that the growth, production output and SRs are significantly higher when shrimp are acclimated for longer periods. [source] | |||||||||||||