منابع مشابه
Social learning in nest-building birds: a role for familiarity
It is becoming apparent that birds learn from their own experiences of nest building. What is not clear is whether birds can learn from watching conspecifics build. As social learning allows an animal to gain information without engaging in costly trial-and-error learning, first-time builders should exploit the successful habits of experienced builders. We presented first-time nest-building mal...
متن کاملGastrointestinal bacteria of certain Antarctic birds and mammals.
An investigation was carried out of the aerobic gram-negative intestinal flora of 158 penguins, 30 skuas, and 66 seals from the Antarctic and sub-Antarctic zones and Phillip Island. Among penguins and seals, 17% and 11%, respectively, were devoid of aerobic enteric organisms, but microscopic examination showed the presence of other bacteria. The coliforms outnumbered the paracolons and nonlacto...
متن کاملextensions, minimality and idempotents of certain semigroup compactifications
در فصل اول مقدمات و پیش نیازهای لازم برای فصل های بعدی فراهم گردیده است . در فصل دوم مساله توسیع مورد توجه قرار گرفته و ابتدا شرایطی که تحت آن از یک فشرده سازی نیم گروهی خاص یک زیرگروه نرمال بسته یک گروه به یک فشرده سازی متناظر با فشرده سازی اولیه برای گروه رسید مورد بررسی قرار گرفته و سپس ارتیاط بین ساختارهای مختلف روی این دو فشرده سازی از جمله ایده آل های مینیمال چپ و راست و... مورد بررسی قرا...
15 صفحه اولWood and Bark Anatomy of Empetraceae; Comments on Paedomorphosis in Woods of Certain Small Shrubs
Wood and bark of 12 collections ofEmpetraceae representing three genera containing seven species (one with two subspecies) are analyzed with respect to quantitative and qualitative features. Empetraceae have vessels somewhat angular in transection, with scalariform perforation plates and scalariform to opposite vessel-ray pitting. Imperforate tracheary elements are all tracheids. Axial parenchy...
متن کاملNeanderthal Use of Fish, Mammals, Birds, Starchy Plants and Wood 125-250,000 Years Ago
Neanderthals are most often portrayed as big game hunters who derived the vast majority of their diet from large terrestrial herbivores while birds, fish and plants are seen as relatively unimportant or beyond the capabilities of Neanderthals. Although evidence for exploitation of other resources (small mammals, birds, fish, shellfish, and plants) has been found at certain Neanderthal sites, th...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Science
سال: 1894
ISSN: 0036-8075,1095-9203
DOI: 10.1126/science.ns-23.574.58