Greenhouse gas emissions in building construction : a case study of One Peking in Hong Kong

Author name used in this manuscript: Geoffrey Qiping Shen2009-2010 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

Communally breeding bats use physiological and behavioural adjustments to optimise daily energy expenditure

Small endotherms must change roosting and thermoregulatory behaviour in response to changes in ambient conditions if they are to achieve positive energy balance. In social species, for example many bats, energy expenditure is influenced by environmental conditions, such as ambient temperature, and also by social thermoregulation. Direct measurements of daily fluctuations in metabolic rates in response to ambient and behavioural variables in the field have not been technologically feasible until recently. During different reproductive periods, we investigated the relationships between ambient temperature, group size and energy expenditure in wild maternity colonies of Bechstein’s bats (Myotis bechsteinii). Bats used behavioural and physiological adjustments to regulate energy expenditure. Whether bats maintained normothermia or used torpor, the number of bats in the roosts as well changed with reproductive status and ambient temperature. During pregnancy and lactation, bats remained mostly normothermic and daily group sizes were relatively large, presumably to participate in the energetic benefits of social thermoregulation. In contrast, smaller groups were formed on days when bats used torpor, which occurred mostly during the post-lactation period. Thus, we were able to demonstrate on wild animals under natural conditions the significance of behavioural and physiological flexibility for optimal thermoregulatory behaviour in small endotherms

The Present and Future Role of Insect-Resistant Genetically Modified Maize in IPM

Commercial, genetically-modified (GM) maize was first planted in the United States (USA, 1996) and Canada (1997) but now is grown in 13 countries on a total of over 35 million hectares (\u3e24% of area worldwide). The first GM maize plants produced a Cry protein derived from the soil bacteriumBacillus thuringiensis (Bt), which made them resistant to European corn borer and other lepidopteran maize pests. New GM maize hybrids not only have resistance to lepidopteran pests but some have resistance to coleopteran pests and tolerance to specific herbicides. Growers are attracted to the Btmaize hybrids for their convenience and because of yield protection, reduced need for chemical insecticides, and improved grain quality. Yet, most growers worldwide still rely on traditional integrated pest management (IPM) methods to control maize pests. They must weigh the appeal of buying insect protection “in the bag” against questions regarding economics, environmental safety, and insect resistance management (IRM). Traditional management of maize insects and the opportunities and challenges presented by GM maize are considered as they relate to current and future insect-resistant products. Four countries, two that currently have commercialize Bt maize (USA and Spain) and two that do not (China and Kenya), are highlighted. As with other insect management tactics (e.g., insecticide use or tillage), GM maize should not be considered inherently compatible or incompatible with IPM. Rather, the effect of GM insect-resistance on maize IPM likely depends on how the technology is developed and used

Protein metabolism in the pectoralis muscle and liver of hibernating bats, Eptesicus fuscus

Seasonal variations in protein metabolism of the pectoralis muscle and liver of the big brown bat, Eptesicus fuscus , are examined in relation to seasonal changes in physiological status. A technique is described for the determination of protein synthetic rates in vivo in animals too small for conventional methods. The results indicate no detectable rates of protein synthesis in hibernating bats during torpor bouts (Table 2). Rates of synthesis in hibernating bats during periods of arousal are comparable to those of active summer bats (Table 2), despite the fact that the hibernating bats had not eaten in over 2 months. Rates of protein degradation were calculated from the rate of urea formation in torpid bats (Figs. 4, 5), the overall loss of pectoralis muscle and liver protein mass during hibernation (Table 3), the proportion of the total time of hibernation spent in torpor and arousal (Table 1), and the observed rates of protein synthesis (Table 2). These estimates (Table 4) indicate negligible rates of protein degradation in torpid bats. However, protein degradation during periodic arousals is comparable to that of summer bats after an overnight fast. These findings are consistent with earlier observations suggesting that significant gluconeogenesis from tissue protein occurs during spontaneous arousals from hibernation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47129/1/360_2004_Article_BF00689738.pd

Carbohydrate and torpor duration in hibernating golden-mantled ground squirrels ( Citellus lateralis )

Plasma glucose concentrations were increased in torpid Citellus lateralis to test the hypothesis that plasma glucose depletion stimulates periodic arousals from torpor during hibernation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47127/1/360_2004_Article_BF00689301.pd

Ginseng administration protects skeletal muscle from oxidative stress induced by acute exercise in rats

Enzymatic activity was analyzed in the soleus, gastrocnemius (red and white) and plantaris muscles of acutely exercised rats after long-term administration of Panax ginseng extract in order to evaluate the protective role of ginseng against skeletal muscle oxidation. Ginseng extract (3, 10, 100, or 500 mg/kg) was administered orally for three months to male Wistar rats weighing 200 ± 50 g before exercise and to non-exercised rats (N = 8/group). The results showed a membrane stabilizing capacity of the extract since mitochondrial function measured on the basis of citrate synthase and 3-hydroxyacyl-CoA dehydrogenase activities was reduced, on average, by 20% (P < 0.05) after exercise but the activities remained unchanged in animals treated with a ginseng dose of 100 mg/kg. Glutathione status did not show significant changes after exercise or treatment. Lipid peroxidation, measured on the basis of malondialdehyde levels, was significantly higher in all muscles after exercise, and again was reduced by about 74% (P < 0.05) by the use of ginseng extract. The administration of ginseng extract was able to protect muscle from exercise-induced oxidative stress irrespective of fiber type

Optimal foraging and fitness in Columbian ground squirrels

Optimal diets were determined for each of 109 individual Columbian ground squirrels ( Spermophilus columbianus ) at two sites in northwestern Montana. Body mass, daily activity time, and vegetation consumption rates for individuals were measured in the field, along with the average water content of vegetation at each ground squirrel colony. I also measured stomach and caecal capacity and turnover rate of plant food through the digestive tract for individuals in the laboratory to construct regressions of digestive capacity as a function of individual body mass. Finally, I obtained literature estimates of average daily energy requirements as a function of body mass and digestible energy content of vegetation. These data were used to construct a linear programming diet model for each individual. The model for each individual was used to predict the proportion of two food types (monocots and dicots) that maximized daily energy intake, given time and digestive constraints on foraging. Individuals were classified as “optimal” or “deviating”, depending on whether their observed diet was significantly different from their predicted optimal diet. I determined the consequences of selecting an optimal diet for energy intake and fitness. As expected, daily energy intake calculated for deviators (based on their observed diet proportion) was less than that for optimal foragers. Deviating foragers do not appear to compensate for their lower calculated energy intake through other factors such as body size or physiological efficiency of processing food. Growth rate, yearly survivorship, and litter size increase with calculated energy intake, and optimal foragers have six times the reproductive success of deviators by age three. Optimal foraging behavior, therefore, appears to confer a considerable fitness advantage.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47783/1/442_2004_Article_BF00318534.pd

Effect of clomiphene citrate on human spermatozoal motility and fertilizing capacity in vitro

The effect of clomiphene citrate (CC) at various concentrations (0.005, 0.05, 0.5, 5, and 50 μg/ml) on the in vitro motility and fertilizing capacity of human spermatozoa was studied. Spermatozoa collected from 14 normal men were washed in modified Krebs-Ringer solution (Biggers, Whitten and Whittingham [BWW] medium) and incubated with CC for 5 hours, the period required for spermatozoal capacitation. The percent motilities of spermatozoa were recorded at 0 and 5 hours during incubation with CC. After incubation, the spermatozoa were washed with BWW medium to remove CC before insemination of the zona-free hamster ova. CC caused a significant dose-dependent decrease in the penetration of denuded hamster ova in comparison with the control (P<0.05). Significant depressive effect on spermatozoal motility was observed with CC at 0.05 μg/ml or higher concentrations (P<0.05). These results indicate that (1) CC decreases human spermatozoal fertilizing capacity in vitro and (2) the inhibitory effect on fertilizing capacity could be due to the sperm-immobilizing activity of CC.link_to_subscribed_fulltex