منابع مشابه
The design and function of birds' nests
All birds construct nests in which to lay eggs and/or raise offspring. Traditionally, it was thought that natural selection and the requirement to minimize the risk of predation determined the design of completed nests. However, it is becoming increasingly apparent that sexual selection also influences nest design. This is an important development as while species such as bowerbirds build struc...
متن کاملLivestock grazing and trampling of birds’ nests: an experiment using artificial nests
The purpose of this study is to experimentally determine the differences between four grazing treatments on the trampling of nests. Additionally, we examine to what extent the trampling probability of nests is higher close to a source of fresh water. We compare the trampling of artificial nests in five different grazing treatments in an experimental design. We use buried clay pigeon targets as ...
متن کاملResponses of Birds to Broken Eggs in Their Nests’
We tested the responses of two bird species which nest on unmovable substrates (e.g., cavities and walls) to simulated and actual egg damage in their nest. Tree Swallows (Tachvcineta bicolor) and Barn Swallows (Hit-undo ruiticaj removed broken eggs and continued to incubate the rest of their clutch, but rcsponse times took up to 8 days, and observed rejection rates were lower than reported for ...
متن کاملOne stone, two birds
The notch signaling pathway is highly conserved and plays an important role in the regulation of cellular proliferation, differentiation and apoptosis. Constitutive activation of notch signaling results in excessive cellular proliferation and a wide range of malignan-cies. However, notch can also act as a tumor suppressor, and its inactivation has been associated with an increased risk of spont...
متن کاملSeismic Behavior of Asymmetric Two-Story X-braced Frames
Concentrically braced frames (CBFs) are one of the efficient lateral load resisting systems in high seismicity regions. One of the common problems with the use of concentrically braced frames is limitation in the architectural application and position of the openings. Two-story X braced frames have more advantages than other configurations of concentrically braced frames, since in many cases th...
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ژورنال
عنوان ژورنال: Scientific American
سال: 1882
ISSN: 0036-8733
DOI: 10.1038/scientificamerican03181882-169