Mortars are among the first building materials used in constructions, even from prehistoric times （8th millennium BC）. Their study reveals a great source of information regarding the evolution of their technological...Mortars are among the first building materials used in constructions, even from prehistoric times （8th millennium BC）. Their study reveals a great source of information regarding the evolution of their technological characteristics and application techniques, the availability and exploitation of raw materials, as well the wider socio-economic aspects of each era. The aim of this paper is to comparatively evaluate the analysis results from approximately 1,000 structural mortar samples taken from various monuments and historic buildings of Greece, dated from the Hellenistic period, until the beginning of the 20th century. The analysis focused in the determination of their physico-mechanical and chemical properties, such as porosity, apparent specific gravity, mechanical strength, aggregates type and granulometry and chemical composition. Through the results＇ evaluation, significant remarks can be made upon the evolution of the raw materials used （binding system, aggregates, additives）, as well as regarding the final properties of historic structural mortars. It is concluded that hydrated lime was the main binding agent used for a long-lasting period of 2.5 millenniums, while mixed type binding systems based on lime and natural pozzolan were systematically used for producing durable mortars, resistant to humidity. In any case, it seems that ancient masons were fully aware of the significant role of mortars in constructions and were capable of exploiting the available raw materials and application techniques to the maximum.展开更多
In this paper, we conduct research on the timeliness and effectiveness of university thought political lesson education practice. What person, how to cultivate people is developing the socialist education enterprise i...In this paper, we conduct research on the timeliness and effectiveness of university thought political lesson education practice. What person, how to cultivate people is developing the socialist education enterprise in our country must solve fundamental problem. College students is a national valuable human resources, are the hope of nation, the future of our motherland. To make university students grow up to be the cause of socialism with Chinese characteristics qualified builders and reliable successors, we not only need to vigorously improve their scientific and cultural quality, and actively improve their ideological and political quality. College students＇ ideological and the political education content system of the science building is refers to according to the requirements of college students＇ ideological and political education goal, to constitute elements of ideological and political education content should be reasonable configuration, make each other, permeate each other, in order to realize the content of organic integration and collaborative development.展开更多
Inclusive fitness benefits depend on recognizing the right individuals to interact with. Social insect nests protect themselves from non-kin intruders through nestmate recognition based on chemical cues. The recogniti...Inclusive fitness benefits depend on recognizing the right individuals to interact with. Social insect nests protect themselves from non-kin intruders through nestmate recognition based on chemical cues. The recognition cues on adult individu- als are from a mixture of genetic and environmental sources, but the ontogeny and use of recognition cues on eggs has not been previously assessed. We studied recognition by workers of eggs that were either nestmates or non-nestmates, and the ontogeny of recognition cues on eggs in the ant Formica fusca, a species with precise egg recognition abilities. Workers were able to dis- criminate among freshly laid eggs with no nest derived cues on them, and the egg surface chemicals varied among nests in these eggs, suggesting that queen derived cues are used in nestmate recognition. The results are discussed in the light of their implica- tions on deceptive social parasite strategies and within colony conflicts展开更多
文摘Mortars are among the first building materials used in constructions, even from prehistoric times （8th millennium BC）. Their study reveals a great source of information regarding the evolution of their technological characteristics and application techniques, the availability and exploitation of raw materials, as well the wider socio-economic aspects of each era. The aim of this paper is to comparatively evaluate the analysis results from approximately 1,000 structural mortar samples taken from various monuments and historic buildings of Greece, dated from the Hellenistic period, until the beginning of the 20th century. The analysis focused in the determination of their physico-mechanical and chemical properties, such as porosity, apparent specific gravity, mechanical strength, aggregates type and granulometry and chemical composition. Through the results＇ evaluation, significant remarks can be made upon the evolution of the raw materials used （binding system, aggregates, additives）, as well as regarding the final properties of historic structural mortars. It is concluded that hydrated lime was the main binding agent used for a long-lasting period of 2.5 millenniums, while mixed type binding systems based on lime and natural pozzolan were systematically used for producing durable mortars, resistant to humidity. In any case, it seems that ancient masons were fully aware of the significant role of mortars in constructions and were capable of exploiting the available raw materials and application techniques to the maximum.
文摘In this paper, we conduct research on the timeliness and effectiveness of university thought political lesson education practice. What person, how to cultivate people is developing the socialist education enterprise in our country must solve fundamental problem. College students is a national valuable human resources, are the hope of nation, the future of our motherland. To make university students grow up to be the cause of socialism with Chinese characteristics qualified builders and reliable successors, we not only need to vigorously improve their scientific and cultural quality, and actively improve their ideological and political quality. College students＇ ideological and the political education content system of the science building is refers to according to the requirements of college students＇ ideological and political education goal, to constitute elements of ideological and political education content should be reasonable configuration, make each other, permeate each other, in order to realize the content of organic integration and collaborative development.
文摘Inclusive fitness benefits depend on recognizing the right individuals to interact with. Social insect nests protect themselves from non-kin intruders through nestmate recognition based on chemical cues. The recognition cues on adult individu- als are from a mixture of genetic and environmental sources, but the ontogeny and use of recognition cues on eggs has not been previously assessed. We studied recognition by workers of eggs that were either nestmates or non-nestmates, and the ontogeny of recognition cues on eggs in the ant Formica fusca, a species with precise egg recognition abilities. Workers were able to dis- criminate among freshly laid eggs with no nest derived cues on them, and the egg surface chemicals varied among nests in these eggs, suggesting that queen derived cues are used in nestmate recognition. The results are discussed in the light of their implica- tions on deceptive social parasite strategies and within colony conflicts
