This paper deals with the validation and theoretical analyses of a simple method for calculating the intrinsic rate of increase, rm, of aphids and mites. This method does not require a detailed fecundity table data. T...This paper deals with the validation and theoretical analyses of a simple method for calculating the intrinsic rate of increase, rm, of aphids and mites. This method does not require a detailed fecundity table data. The value of rm can be estimated by the simple equation: rm=0.74ln (Md)/d, where d is the time from birth to first reproduction; Md is the number of female offspring produced per original female in 2d. This method was developed by Wyatt and White. We reached the following conclusions from our study: When the parameter, Md is less than 1, this equation is not appropriate for estimating rm of populations; When the parameter, Md is larger than 1 and about 70% or more of the reproductive contribution to the rm is achieved in 2d, the equation is appropriate for calculatng the rm of aphids and mites.As Md decreases, the required reproductive contribution to the rm in 2d corresponding to the constant 0.74 will increase. However, whether 70% or more of reproductive contribution to rm is achieved in 2d still is a problem for whole taxa of aphids and mites. Therefore, further siudy on reproductive distribution will be required for practical application of this method.展开更多
The method developed by Wyatt and White (1977) was applied to calculate the intrinsic rates of increase for parasitoids based on 23 fecundity data sets from the literature. The studies showed that there existed the li...The method developed by Wyatt and White (1977) was applied to calculate the intrinsic rates of increase for parasitoids based on 23 fecundity data sets from the literature. The studies showed that there existed the linear relationship between the accurate values of rm and In f (Md) / d or In (A/d/2) / d, that is, 1) rm= 0.845 In (Md) / d or 2) rm= 0.880 In (Md/ 2) / d. Where d is the prereproductive time, Md is the number of female offspring produced per original female from the first to the dthday of reproduction, and Md/2 is the number of female offspring produced per original female from the first to the (d/ 2) th day of reproduction. These equations can provide the accurate estimates of rm for parasitoids in this study. The approach is advantageous because it does not require the construction of detailed fecundity tables for estimating parasitoid rates of increase. Of course, whether these equations are appropriate for the other taxa will need to be further studied.展开更多
We evaluated the effects of lithium on the survival, growth, and reproduction ofD. tibetana in the laboratory. The safe concentration value was 69.3 mg/L. The time to first brood was significant lower for individuals ...We evaluated the effects of lithium on the survival, growth, and reproduction ofD. tibetana in the laboratory. The safe concentration value was 69.3 mg/L. The time to first brood was significant lower for individuals reared in 5 and 10 mg/L （24.4 and 24.0 d, respectively） compared with individuals reared in 20, 40, or 60 mg/L. Females reared in 5 mg/L lithium produced a mean of 16.5 neonates/brood and had the highest number of broods （3.0±1.95）. The rate of egg production （a）, the intrinsic rate of increase （rm）, net reproduction rate （R0）, and finite rate of increase （2） were highest for D. tibetana reared at 5 and 10 mg/L lithium, and the duration of development was shorter than for the remaining groups. The results indicated that rearing in 5 10 mg/L lithium can accelerate the growth and reproduction ofD. tibetana.展开更多
Following a period of significant development at the end of the 1990s, with economic growth rates greater than those of the European Union, the Portuguese economy stagnated in 2002 and even declined in 2003. The curre...Following a period of significant development at the end of the 1990s, with economic growth rates greater than those of the European Union, the Portuguese economy stagnated in 2002 and even declined in 2003. The current context of international crisis has just interrupted the fragile growth trend initiated in 2004： In fact, real GDP, which increased by 1.9 percent in 2007, had a growth rate of zero in 2008 and declined by 2.9 percent in 2009. The crisis has abruptly increased the closure of companies and unemployment jumped from 7.3% in the second haft of 2008 to 10.1% in the forth quarter of 2009. Notwithstanding, social dialog was resilient to this situation of economic crisis, as shown by the number of collective agreements negotiated by the social partners, the number of workers covered by collective agreements and the observed increase in real wages. Additionally, social partners have agreed on a reform of the Labour Code. Are this data enough evidence of social concentration on crisis management？ This paper will analyze this issue, giving particular attention to collective bargaining in Portugal and the crisis impact on the industrial relations system and their actors展开更多
In this paper, we first examine various causes of China＇s unexpected low economic growth rate since the beginning of 2012. Particularly, we propose the possibility of one tendency masking the other tendency. That is,...In this paper, we first examine various causes of China＇s unexpected low economic growth rate since the beginning of 2012. Particularly, we propose the possibility of one tendency masking the other tendency. That is, there is a tendency of neglecting and downplaying GDP while making fewer efforts to develop economy in some regions that oppose GDP worship and irrational pursuit of and competition for GDP,, which deserves our full attention. We further propose in this paper that the decline of China＇s potential economic growth rate should keep a gradual process and the government should favor consumption while not overlooking investment, given that a certain amount of moderate investment will remain the key impetus to China＇s economic growth over a certain period in the future.展开更多
文摘This paper deals with the validation and theoretical analyses of a simple method for calculating the intrinsic rate of increase, rm, of aphids and mites. This method does not require a detailed fecundity table data. The value of rm can be estimated by the simple equation: rm=0.74ln (Md)/d, where d is the time from birth to first reproduction; Md is the number of female offspring produced per original female in 2d. This method was developed by Wyatt and White. We reached the following conclusions from our study: When the parameter, Md is less than 1, this equation is not appropriate for estimating rm of populations; When the parameter, Md is larger than 1 and about 70% or more of the reproductive contribution to the rm is achieved in 2d, the equation is appropriate for calculatng the rm of aphids and mites.As Md decreases, the required reproductive contribution to the rm in 2d corresponding to the constant 0.74 will increase. However, whether 70% or more of reproductive contribution to rm is achieved in 2d still is a problem for whole taxa of aphids and mites. Therefore, further siudy on reproductive distribution will be required for practical application of this method.
文摘The method developed by Wyatt and White (1977) was applied to calculate the intrinsic rates of increase for parasitoids based on 23 fecundity data sets from the literature. The studies showed that there existed the linear relationship between the accurate values of rm and In f (Md) / d or In (A/d/2) / d, that is, 1) rm= 0.845 In (Md) / d or 2) rm= 0.880 In (Md/ 2) / d. Where d is the prereproductive time, Md is the number of female offspring produced per original female from the first to the dthday of reproduction, and Md/2 is the number of female offspring produced per original female from the first to the (d/ 2) th day of reproduction. These equations can provide the accurate estimates of rm for parasitoids in this study. The approach is advantageous because it does not require the construction of detailed fecundity tables for estimating parasitoid rates of increase. Of course, whether these equations are appropriate for the other taxa will need to be further studied.
基金Supported by the National Natural Science Foundation of China(Nos.30371112,30671625,40776065)
文摘We evaluated the effects of lithium on the survival, growth, and reproduction ofD. tibetana in the laboratory. The safe concentration value was 69.3 mg/L. The time to first brood was significant lower for individuals reared in 5 and 10 mg/L （24.4 and 24.0 d, respectively） compared with individuals reared in 20, 40, or 60 mg/L. Females reared in 5 mg/L lithium produced a mean of 16.5 neonates/brood and had the highest number of broods （3.0±1.95）. The rate of egg production （a）, the intrinsic rate of increase （rm）, net reproduction rate （R0）, and finite rate of increase （2） were highest for D. tibetana reared at 5 and 10 mg/L lithium, and the duration of development was shorter than for the remaining groups. The results indicated that rearing in 5 10 mg/L lithium can accelerate the growth and reproduction ofD. tibetana.
文摘Following a period of significant development at the end of the 1990s, with economic growth rates greater than those of the European Union, the Portuguese economy stagnated in 2002 and even declined in 2003. The current context of international crisis has just interrupted the fragile growth trend initiated in 2004： In fact, real GDP, which increased by 1.9 percent in 2007, had a growth rate of zero in 2008 and declined by 2.9 percent in 2009. The crisis has abruptly increased the closure of companies and unemployment jumped from 7.3% in the second haft of 2008 to 10.1% in the forth quarter of 2009. Notwithstanding, social dialog was resilient to this situation of economic crisis, as shown by the number of collective agreements negotiated by the social partners, the number of workers covered by collective agreements and the observed increase in real wages. Additionally, social partners have agreed on a reform of the Labour Code. Are this data enough evidence of social concentration on crisis management？ This paper will analyze this issue, giving particular attention to collective bargaining in Portugal and the crisis impact on the industrial relations system and their actors
文摘In this paper, we first examine various causes of China＇s unexpected low economic growth rate since the beginning of 2012. Particularly, we propose the possibility of one tendency masking the other tendency. That is, there is a tendency of neglecting and downplaying GDP while making fewer efforts to develop economy in some regions that oppose GDP worship and irrational pursuit of and competition for GDP,, which deserves our full attention. We further propose in this paper that the decline of China＇s potential economic growth rate should keep a gradual process and the government should favor consumption while not overlooking investment, given that a certain amount of moderate investment will remain the key impetus to China＇s economic growth over a certain period in the future.
