Sexual selection by female mating preference for male nuptial coloration has been suggested as a driving force in the rapid speciation of Lake Victoria cichlid fish. This process could have been facilitated or acceler...Sexual selection by female mating preference for male nuptial coloration has been suggested as a driving force in the rapid speciation of Lake Victoria cichlid fish. This process could have been facilitated or accelerated by genetic associations between female preference loci and male coloration loci. Preferences, as well as coloration, are heritable traits and are probably determined by more than one gene. However, little is known about potential genetic associations between these traits. In turbid water, we found a population that is variable in male nuptial coloration from blue to yellow to red. Males at the extreme ends of the phenotype distribution resemble a reproductively isolated species pair in clear water that has diverged into one species with blue-grey males and one species with bright red males. Females of the turbid water population vary in mating preference coinciding with the male phenotype distribution. For the current study, these females were mated to blue males. We measured the coloration of the sires and male offspring. Parents-offspring regression showed that the sires did not affect male offspring coloration, which confirms earlier findings that the blue species breeds true. In contrast, male offspring coloration was determined by the identity of the dams, which suggests that there is heritable variation in male color genes between females. However, we found that mating preferences of the dams were not correlated with male offspring coloration. Thus, there is no evidence for strong genetic linkage between mating preference and the preferred trait in this population [Current Zoology 56 （1）： 57-64 2010].展开更多
The theory of ecological speciation suggests that assortative mating evolves most easily when mating preferences aredirectly linked to ecological traits that are subject to divergent selection. Sensory adaptation can ...The theory of ecological speciation suggests that assortative mating evolves most easily when mating preferences aredirectly linked to ecological traits that are subject to divergent selection. Sensory adaptation can play a major role in this process,because selective mating is often mediated by sexual signals: bright colours, complex song, pheromone blends and so on. Whendivergent sensory adaptation affects the perception of such signals, mating patterns may change as an immediate consequence.Alternatively, mating preferences can diverge as a result of indirect effects: assortative mating may be promoted by selectionagainst intermediate phenotypes that are maladapted to their (sensory) environment. For Lake Victoria cichlids, the visual environmentconstitutes an important selective force that is heterogeneous across geographical and water depth gradients. We investigatethe direct and indirect effects of this heterogeneity on the evolution of female preferences for alternative male nuptial colours(red and blue) in the genus Pundamilia. Here, we review the current evidence for divergent sensory drive in this system, extractgeneral principles, and discuss future perspectives [Current Zoology 56 (3): 285-299, 2010].展开更多
This study was to examine the influence of reactions of char–O2and char–steam on the char reactivity evolution.A newly-designed fixed-bed reactor was used to conduct gasification experiments using Victorian brown co...This study was to examine the influence of reactions of char–O2and char–steam on the char reactivity evolution.A newly-designed fixed-bed reactor was used to conduct gasification experiments using Victorian brown coal at800 °C. The chars prepared from the gasification experiments were then collected and subjected to reactivity characterisation(ex-situ reactivity) using TGA(thermogravimetric analyser) in air. The results indicate that the char reactivity from TGA was generally high when the char experienced intensive gasification reactions in 0.3%O2in the fixed-bed reactor. The addition of steam into the gasification not only enhanced the char conversion significantly but also reduced the char reactivity dramatically. The curve shapes of the char reactivity with involvement of steam were very different from that with O2 gasification, implying the importance of gasifying agents to char properties.展开更多
The skill of most ENSO prediction models has declined significantly since 2000.This decline may be due to a weakening of the correlation between tropical predictors and ENSO.Moreover,the effects of extratropical ocean...The skill of most ENSO prediction models has declined significantly since 2000.This decline may be due to a weakening of the correlation between tropical predictors and ENSO.Moreover,the effects of extratropical ocean variability on ENSO have increased during this period.To improve ENSO predictability,the authors investigate the influence of the extratropical Atlantic and Pacific oceans on ENSO during the pre-2000 and post-2000 periods,and find that the influence of the northern tropical Atlantic sea surface temperature(NTA SST)on ENSO has significantly increased since 2000.Furthermore,there is a much earlier and stronger correlation between NTA SST and ENSO over the central-eastern Pacific during June-July-August in the post-2000 period compared with the pre-2000 period.The extratropical Pacific SST predictors for ENSO retain an approximate 10-month lead time after 2000.The authors use SST signals in the extratropical Atlantic and Pacific to predict ENSO using a statistical prediction model.This results in a significant improvement in ENSO prediction skill and an obvious decrease in the spring predictability barrier phenomenon of ENSO.These results indicate that extratropical Atlantic and Pacific SSTs can make substantial contributions to ENSO prediction,and can be used to enhance ENSO predictability after 2000.展开更多
George Bernard Shaw is one of the prominent playwrights in the world. His masterpiece Mrs. Warren＇ s Profession has an important effect on the world. This play is so influential that it injects a new thing into the b...George Bernard Shaw is one of the prominent playwrights in the world. His masterpiece Mrs. Warren＇ s Profession has an important effect on the world. This play is so influential that it injects a new thing into the black society. This play also inspires women to stand up to fight against the old power. Only by describing the suffering of Warren and Vivie can the writer expose the social root forming the brothel in the capital society. It also shows Shaw is critical and sympathetic towards women in the society. This work has been studied in different aspects by scholars. Based on women in Victorian Society, this paper mainly discusses the main characters Warren and Vivie Warren to form a distinctive contrast between submissive woman and new woman. Warren and Vivie serve an example to illustrate the features of Victorian women. War Warren, a symbol of the submissive woman who runs brothel, submits to the reality and makes a living by doing exploiting, while as a new woman and a positive figure, Vivie is brave enough to break away from all the traditional bondage and pursues a new life after knowing that her mother has been doing this kind of work. All the differences in the character lead to the break-up between the two.展开更多
African indigenous vegetables have many nutritional and health benefits that have not been well researched and fully exploited. The objective of this study was to determine iron and protein contents of seven priority ...African indigenous vegetables have many nutritional and health benefits that have not been well researched and fully exploited. The objective of this study was to determine iron and protein contents of seven priority African indigenous vegetables found in Eastern Africa. The vegetables were planted at two sites, Maseno University, Maseno in western Kenya and Jomo Kenyatta University of Agriculture and Technology （JKUAT）, Juja in Central Kenya between 2006 and 2008. These vegetables were organically grown and edible parts of each of the vegetable harvested during vegetative growth stages just before onset of flowering and analysed for iron and protein contents. Nightshade and cowpea had high levels of both iron and protein. Pumpkin leaves and amaranths had high iron content while spiderplant and slenderleaf had high protein levels. Both iron and protein levels differed significantly between the seven vegetables at both sites. Nightshade and cowpea contained iron and protein levels that would provide 100% of the recommended daily allowance （RDA） iron and 50% of recommended daily allowance protein for optimal human growth and health. These results help to demonstrate the nutritional value of African indigenous vegetables and their potential use in nutrition intervention programs.展开更多
This paper investigates the interdecadal variability in the lagged relationship between the spring Victoria mode(VM)and the following-winter El Ni?o–Southern Oscillation(ENSO).It is found that the relationship is str...This paper investigates the interdecadal variability in the lagged relationship between the spring Victoria mode(VM)and the following-winter El Ni?o–Southern Oscillation(ENSO).It is found that the relationship is strong during high correlation(HC)periods,e.g.1957–1964 and 1981–2004,but weak during low correlation(LC)periods,e.g.1907–1924,1926–1956,1965–1980,and2005–2008.The surface air–sea coupling and the evolution of subsurface ocean temperature anomaliesh along the equatorial Paci?c associated with the VM are found to be strong during HC periods and weak during LC periods,which results in a stronger impact of the VM on the following-winter ENSO during HC periods.The interdecadal change in the relationship between the VM and ENSO is mainly due to the interdecadal change in the intensity of the VM,which is found to be in?uenced by the North Paci?c Oscillation.Our?ndings may improve the prediction skill for the onset of ENSO events.展开更多
The sea surface temperature anomalies （SSTAs） associated with the Victoria mode （VM） can persist into the following season and then influence climate variability in the tropical Pacific. This paper demonstrates th...The sea surface temperature anomalies （SSTAs） associated with the Victoria mode （VM） can persist into the following season and then influence climate variability in the tropical Pacific. This paper demonstrates the connection between the preceding boreal winter VM and precipitation in the following spring over the southeastern United States （SE USA） and the Gulf of Mexico （GM）. The results indicate that a positive （negative） preceding winter VM is usually followed by increased （reduced） precipitation over the SE USA and GM during the following spring. The corresponding mechanism is similar, but slightly different to, the seasonal footprinting mechanism. For positive VM cases, the preceding-winter VM-related SSTAs appear to persist into the following spring via air- sea interactions, which then induce low-level convergence and vigorous ascending motion, leading to an adjustment of the zonal and meridional circulation. This adjustment can then influence the local Hadley cell by weakening the downward branch. These anomalous patterns of vertical airflow enhance spring precipitation over the SE USA and GM under suitable moisture conditions. Hence, this work demonstrates that the preceding-winter VM has the potential to regulate precipitation over the SE USA and GM in the following spring.展开更多
In order to minimise the bushfires negative impacts on society, an efficient andreliable bushfire detection system was proposed to assess the devastated effects of the2009 Victorian bushfires.It is possible to utilise...In order to minimise the bushfires negative impacts on society, an efficient andreliable bushfire detection system was proposed to assess the devastated effects of the2009 Victorian bushfires.It is possible to utilise the repetitive capability of satellite remotesensing imagery to identify the location of change to the Earth's surface and integrate thedifferent remotely sensed indices.The results confirm that the procedure can offer essentialspatial information for bushfire assessment.展开更多
This paper examines the livelihood challenges experienced in Rwanjaba Lakeshore Community during the period of low water level in Lake Victoria between 2004 and 2007 and identifies the livelihood coping strategies tha...This paper examines the livelihood challenges experienced in Rwanjaba Lakeshore Community during the period of low water level in Lake Victoria between 2004 and 2007 and identifies the livelihood coping strategies that were adopted to address them.A total of 55 households were randomly sampled and the data collection methods included household questionnaires and participant observations.The data were analyzed using the Statistical Package for Social Science(SPSS) and the results presented with the help of descriptive statistics.The livelihood challenges experienced during the low lake water level included fish shortage(34.5%),household food scarcity(23.6%),sex for fish(18.2%),family breakdown(12.7%),increased theft(7.2%) and accidents due to the exposed rocks in the lake(3.6%).The livelihood coping strategies adopted to redress the challenges included causal labour(32.7%),maize roasting(23.6%),sand mining(18.2%),selling of snacks(12.7%),selling household property(9.1%) and resorting shop and market credits(3.6%).The paper proposes a number of recommendations for improving the livelihood of the community ranging from policy reforms to the diversification of activities.展开更多
基金supported by the Netherlands Science Fotmdation (NWO-ALW 810.64.011)research grants from Leiden University Fundthe Schure-Beijerinck-Popping Foundation
文摘Sexual selection by female mating preference for male nuptial coloration has been suggested as a driving force in the rapid speciation of Lake Victoria cichlid fish. This process could have been facilitated or accelerated by genetic associations between female preference loci and male coloration loci. Preferences, as well as coloration, are heritable traits and are probably determined by more than one gene. However, little is known about potential genetic associations between these traits. In turbid water, we found a population that is variable in male nuptial coloration from blue to yellow to red. Males at the extreme ends of the phenotype distribution resemble a reproductively isolated species pair in clear water that has diverged into one species with blue-grey males and one species with bright red males. Females of the turbid water population vary in mating preference coinciding with the male phenotype distribution. For the current study, these females were mated to blue males. We measured the coloration of the sires and male offspring. Parents-offspring regression showed that the sires did not affect male offspring coloration, which confirms earlier findings that the blue species breeds true. In contrast, male offspring coloration was determined by the identity of the dams, which suggests that there is heritable variation in male color genes between females. However, we found that mating preferences of the dams were not correlated with male offspring coloration. Thus, there is no evidence for strong genetic linkage between mating preference and the preferred trait in this population [Current Zoology 56 （1）： 57-64 2010].
基金funded by the Swiss National Science Foundation (SNSF)the Netherlands Foundation for Scientific Research (NWO-ALW and NWO-WOTRO)
文摘The theory of ecological speciation suggests that assortative mating evolves most easily when mating preferences aredirectly linked to ecological traits that are subject to divergent selection. Sensory adaptation can play a major role in this process,because selective mating is often mediated by sexual signals: bright colours, complex song, pheromone blends and so on. Whendivergent sensory adaptation affects the perception of such signals, mating patterns may change as an immediate consequence.Alternatively, mating preferences can diverge as a result of indirect effects: assortative mating may be promoted by selectionagainst intermediate phenotypes that are maladapted to their (sensory) environment. For Lake Victoria cichlids, the visual environmentconstitutes an important selective force that is heterogeneous across geographical and water depth gradients. We investigatethe direct and indirect effects of this heterogeneity on the evolution of female preferences for alternative male nuptial colours(red and blue) in the genus Pundamilia. Here, we review the current evidence for divergent sensory drive in this system, extractgeneral principles, and discuss future perspectives [Current Zoology 56 (3): 285-299, 2010].
基金Support by the Victorian State Government under its Energy Technology Innovation Strategy programme and the 12th Five-Year Plan of National Science and Technology of China(2012BAA04B02)
文摘This study was to examine the influence of reactions of char–O2and char–steam on the char reactivity evolution.A newly-designed fixed-bed reactor was used to conduct gasification experiments using Victorian brown coal at800 °C. The chars prepared from the gasification experiments were then collected and subjected to reactivity characterisation(ex-situ reactivity) using TGA(thermogravimetric analyser) in air. The results indicate that the char reactivity from TGA was generally high when the char experienced intensive gasification reactions in 0.3%O2in the fixed-bed reactor. The addition of steam into the gasification not only enhanced the char conversion significantly but also reduced the char reactivity dramatically. The curve shapes of the char reactivity with involvement of steam were very different from that with O2 gasification, implying the importance of gasifying agents to char properties.
基金This research was supported by the National Natural Science Foundation of China[grant number 41975070]the Identification and mechanism study of global warming‘hiatus’phenomenon of 973 project of China[grant number 2016YFA0601801].
文摘The skill of most ENSO prediction models has declined significantly since 2000.This decline may be due to a weakening of the correlation between tropical predictors and ENSO.Moreover,the effects of extratropical ocean variability on ENSO have increased during this period.To improve ENSO predictability,the authors investigate the influence of the extratropical Atlantic and Pacific oceans on ENSO during the pre-2000 and post-2000 periods,and find that the influence of the northern tropical Atlantic sea surface temperature(NTA SST)on ENSO has significantly increased since 2000.Furthermore,there is a much earlier and stronger correlation between NTA SST and ENSO over the central-eastern Pacific during June-July-August in the post-2000 period compared with the pre-2000 period.The extratropical Pacific SST predictors for ENSO retain an approximate 10-month lead time after 2000.The authors use SST signals in the extratropical Atlantic and Pacific to predict ENSO using a statistical prediction model.This results in a significant improvement in ENSO prediction skill and an obvious decrease in the spring predictability barrier phenomenon of ENSO.These results indicate that extratropical Atlantic and Pacific SSTs can make substantial contributions to ENSO prediction,and can be used to enhance ENSO predictability after 2000.
文摘George Bernard Shaw is one of the prominent playwrights in the world. His masterpiece Mrs. Warren＇ s Profession has an important effect on the world. This play is so influential that it injects a new thing into the black society. This play also inspires women to stand up to fight against the old power. Only by describing the suffering of Warren and Vivie can the writer expose the social root forming the brothel in the capital society. It also shows Shaw is critical and sympathetic towards women in the society. This work has been studied in different aspects by scholars. Based on women in Victorian Society, this paper mainly discusses the main characters Warren and Vivie Warren to form a distinctive contrast between submissive woman and new woman. Warren and Vivie serve an example to illustrate the features of Victorian women. War Warren, a symbol of the submissive woman who runs brothel, submits to the reality and makes a living by doing exploiting, while as a new woman and a positive figure, Vivie is brave enough to break away from all the traditional bondage and pursues a new life after knowing that her mother has been doing this kind of work. All the differences in the character lead to the break-up between the two.
文摘African indigenous vegetables have many nutritional and health benefits that have not been well researched and fully exploited. The objective of this study was to determine iron and protein contents of seven priority African indigenous vegetables found in Eastern Africa. The vegetables were planted at two sites, Maseno University, Maseno in western Kenya and Jomo Kenyatta University of Agriculture and Technology （JKUAT）, Juja in Central Kenya between 2006 and 2008. These vegetables were organically grown and edible parts of each of the vegetable harvested during vegetative growth stages just before onset of flowering and analysed for iron and protein contents. Nightshade and cowpea had high levels of both iron and protein. Pumpkin leaves and amaranths had high iron content while spiderplant and slenderleaf had high protein levels. Both iron and protein levels differed significantly between the seven vegetables at both sites. Nightshade and cowpea contained iron and protein levels that would provide 100% of the recommended daily allowance （RDA） iron and 50% of recommended daily allowance protein for optimal human growth and health. These results help to demonstrate the nutritional value of African indigenous vegetables and their potential use in nutrition intervention programs.
基金supported by the National Natural Science Foundation of China [grant number 41790474]the National Program on Global Change and Air–Sea Interaction[grant numbers GASI-IPOVAI-06 and GASI-IPOVAI-03]the National Key Technology Research and Development Program of the Ministry of Science and Technology of China [grant number 2015BAC03B07]
文摘This paper investigates the interdecadal variability in the lagged relationship between the spring Victoria mode(VM)and the following-winter El Ni?o–Southern Oscillation(ENSO).It is found that the relationship is strong during high correlation(HC)periods,e.g.1957–1964 and 1981–2004,but weak during low correlation(LC)periods,e.g.1907–1924,1926–1956,1965–1980,and2005–2008.The surface air–sea coupling and the evolution of subsurface ocean temperature anomaliesh along the equatorial Paci?c associated with the VM are found to be strong during HC periods and weak during LC periods,which results in a stronger impact of the VM on the following-winter ENSO during HC periods.The interdecadal change in the relationship between the VM and ENSO is mainly due to the interdecadal change in the intensity of the VM,which is found to be in?uenced by the North Paci?c Oscillation.Our?ndings may improve the prediction skill for the onset of ENSO events.
基金the China Special Fund for Meteorological Research in the Public Interest[grant number GYHY201506013]the National Basic Research Program of China[973 Program,grant number 2012CB955200]+2 种基金the National Natural Science Foundation of China for Excellent Young Scholars[grant number 41522502]the National Natural Science Foundation of China[grant number 41475037]the Strategic Priority Research Program of the Chinese Academy of Sciences[grant number XDA11010303]
文摘The sea surface temperature anomalies （SSTAs） associated with the Victoria mode （VM） can persist into the following season and then influence climate variability in the tropical Pacific. This paper demonstrates the connection between the preceding boreal winter VM and precipitation in the following spring over the southeastern United States （SE USA） and the Gulf of Mexico （GM）. The results indicate that a positive （negative） preceding winter VM is usually followed by increased （reduced） precipitation over the SE USA and GM during the following spring. The corresponding mechanism is similar, but slightly different to, the seasonal footprinting mechanism. For positive VM cases, the preceding-winter VM-related SSTAs appear to persist into the following spring via air- sea interactions, which then induce low-level convergence and vigorous ascending motion, leading to an adjustment of the zonal and meridional circulation. This adjustment can then influence the local Hadley cell by weakening the downward branch. These anomalous patterns of vertical airflow enhance spring precipitation over the SE USA and GM under suitable moisture conditions. Hence, this work demonstrates that the preceding-winter VM has the potential to regulate precipitation over the SE USA and GM in the following spring.
文摘In order to minimise the bushfires negative impacts on society, an efficient andreliable bushfire detection system was proposed to assess the devastated effects of the2009 Victorian bushfires.It is possible to utilise the repetitive capability of satellite remotesensing imagery to identify the location of change to the Earth's surface and integrate thedifferent remotely sensed indices.The results confirm that the procedure can offer essentialspatial information for bushfire assessment.
文摘This paper examines the livelihood challenges experienced in Rwanjaba Lakeshore Community during the period of low water level in Lake Victoria between 2004 and 2007 and identifies the livelihood coping strategies that were adopted to address them.A total of 55 households were randomly sampled and the data collection methods included household questionnaires and participant observations.The data were analyzed using the Statistical Package for Social Science(SPSS) and the results presented with the help of descriptive statistics.The livelihood challenges experienced during the low lake water level included fish shortage(34.5%),household food scarcity(23.6%),sex for fish(18.2%),family breakdown(12.7%),increased theft(7.2%) and accidents due to the exposed rocks in the lake(3.6%).The livelihood coping strategies adopted to redress the challenges included causal labour(32.7%),maize roasting(23.6%),sand mining(18.2%),selling of snacks(12.7%),selling household property(9.1%) and resorting shop and market credits(3.6%).The paper proposes a number of recommendations for improving the livelihood of the community ranging from policy reforms to the diversification of activities.
