منابع مشابه
Anomalies & Tadpoles
We show that massless RR tadpoles in vacuum configurations with open and unoriented strings are always related to anomalies. RR tadpoles arising from sectors of the internal SCFT with non-vanishing Witten index are in one-to-one correspondence with conventional irreducible anomalies. The anomalous content of the remaining RR tadpoles can be disclosed by considering anomalous amplitudes with hig...
متن کاملDecapitating Tadpoles
We argue that perturbative quantum field theory and string theory can be consistently modified in the infrared to eliminate, in a radiatively stable manner, tadpole instabilities that arise after supersymmetry breaking. This is achieved by deforming the propagators of classically massless scalar fields and the graviton so as to cancel the contribution of their zero modes. In string theory, this...
متن کاملUsing Tadpoles to Reduce
A parallel variant of breadth-rst search for distributed computing is presented. The variant allows exhaustive enumeration of elements of a search space (implicitly deened graph) in which the representation of all graph nodes would otherwise require more than the total available memory. This algorithm requires the use of a tadpole data structure to partition the search space into connected subg...
متن کاملNitrogen Excretion in Xenopus Tadpoles
fact that Munro's experiments were carried out under less satisfactory conditions; he himself states that more than half the tadpoles died during the first week, and that from the original 250 eggs only 10 survived to metamorphosis. Our own animals were well fed on a high-protein diet and had a high survival rate. Munro, on the other hand, does not state that his animals were fed but only that ...
متن کاملCharacter displacement in polyphenic tadpoles.
Biologists have long known that closely related species are often phenotypically different where they occur together, but are indistinguishable where they occur alone. The causes of such character displacement are controversial, however. We used polyphenic spadefoot toad tadpoles (Spea bombifrons and S. multiplicata) to test the hypothesis that character displacement evolves to minimize competi...
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ژورنال
عنوان ژورنال: Nature
سال: 1910
ISSN: 0028-0836,1476-4687
DOI: 10.1038/082489b0