منابع مشابه
Recent Works on Tourism In
Holiday in Mexico: Critical Refl ections on Tourism and Tourist Encounters. Edited by Dina Berger and Andrew Grant Wood. Durham, NC: Duke University Press, 2010. Pp. xv + 393. $24.95 paper. $89.95 cloth. Economies of Desire: Sex and Tourism in Cuba and the Dominican Republic. By Amalia L. Cabezas. Philadelphia: Temple University Press, 2009. Pp. xii + 218. $24.95 paper. Negotiating Paradise: U....
متن کاملEchinoderms
two fish. In the wild, kittiwakes have to learn to look for particular colours and patterns in the ocean to find the best place to fish. The researchers tried to recreate this for the captive birds by making them search for their food among a chequerboard of different coloured bowls. Chicks on the unrestricted fatty diet quickly learned which bowls contained food, but chicks on lean rations wer...
متن کاملEchinoderms Have Bilateral Tendencies
Echinoderms take many forms of symmetry. Pentameral symmetry is the major form and the other forms are derived from it. However, the ancestors of echinoderms, which originated from Cambrian period, were believed to be bilaterians. Echinoderm larvae are bilateral during their early development. During embryonic development of starfish and sea urchins, the position and the developmental sequence ...
متن کاملAntimicrobial peptides in Echinoderms
Antimicrobial peptides (AMPs) are important immune effector molecules for invertebrates, including echinoderms, which lack a vertebrate-type adaptive immune system. Here we summarize the knowledge of such peptides in echinoderms. Strongylocins are a novel family of cysteine-rich AMPs, recently identified in the sea urchins, Strongylocentrotus droebachiensis and S. purpuratus. Although these mol...
متن کاملImmune phenomena in echinoderms.
Advances in biochemistry and molecular biology have made it possible to identify a number of mechanisms active in the immune phenomena of echinoderms. It is obvious that echinoderms have the ability to distinguish between different foreign objects (pathologically changed tissues, microorganisms, parasites, grafts) and to express variable effector mechanisms which are elicited specifically and r...
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ژورنال
عنوان ژورنال: Nature
سال: 1873
ISSN: 0028-0836,1476-4687
DOI: 10.1038/008103d0