3,834 research outputs found

    The analytic structure and the transcendental weight of the BFKL ladder at NLL accuracy

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    We study some analytic properties of the BFKL ladder at next-to-leading logarithmic accuracy (NLLA). We use a procedure by Chirilli and Kovchegov to construct the NLO eigenfunctions, and we show that the BFKL ladder can be evaluated order by order in the coupling in terms of certain generalised single-valued multiple polylogarithms recently introduced by Schnetz. We develop techniques to evaluate the BFKL ladder at any loop order, and we present explicit results up to five loops. Using the freedom in defining the matter content of the NLO BFKL eigenvalue, we obtain conditions for the BFKL ladder in momentum space at NLLA to have maximal transcendental weight. We observe that, unlike in moment space, the result in momentum space in N = 4 SYM is not identical to the maximal weight part of QCD, and moreover that there is no gauge theory with this property. We classify the theories for which the BFKL ladder at NLLA has maximal weight in terms of their field content, and we find that these theories are highly constrained: there are precisely four classes of theories with this property involving only fundamental and adjoint matter, all of which have a vanishing one-loop beta function and a matter content that fits into supersymmetric multiplets. Our findings indicate that theories which have maximal weight are highly constrained and point to the possibility that there is a connection between maximal transcendental weight and superconformal symmetry.Comment: 45 pages, 1 figure, 1 table. v2: published versio

    Late pleistocene ignimbrites at Los Azufres volcanic center, Mexico : implications for the present magmatic cycle

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    Depuis le Pléistocène inférieur, le complexe volcanique de Los Azufres alterne l'émission de magmas différenciés - rhyolites et dacites - et basiques. Compte tenu de cette longue histoire, du caractère "cyclique" des phases magmatiques, et de l'âge récent (26 000 à 38 000 ans) des dernières ignimbrites, on peut penser que l'activité éruptive, liée à un (ou plusieurs) volumineux réservoir(s) de magma différencié à faible profondeur, n'est pas terminée, en particulier au sud du complexe, où se situe le champ géothermique et où vivent plus de 200 000 personnes. (Résumé d'auteur

    Inguinal Hernia In A Shorthorn Bull.

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    On Oct. 11, 1949, a 4-yearold Shorthorn Bull was referred to Stange Memorial Clinic An accompanying letter from the attending veterinarian stated that for several days the animal had shown signs of intermittent colic by kicking at his abdomen for short periods, inappetence, and general depression

    A subjective global checklist of the extant non-marine Ostracoda (Crustacea)

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    We present an updated, subjective list of the extant, non-marine ostracod genera and species of the world, with their distributions in the major zoogeographical regions, as well as a list of the genera in their present hierarchical taxonomic positions. The list includes all taxa described and taxonomic alterations made up to I July 2018. Taxonomic changes include 17 new combinations, 5 new names, I emended specific name and 11 new synonymies (1 tribe, 4 genera, 6 species). Taking into account the recognized synonymies, there are presently 2330 subjective species of non-marine ostracods in 270 genera. The most diverse family in non-marine habitats is the Cyprididae, comprising 43.2% of all species, followed by the Candonidae (29.0%), Entocytheridae (9.1%) and the Limnocytheridae (7.0%). An additional 13 families comprise the remaining 11.8% of described species. The Palaearctic zoogeographical region has the greatest number of described species (799), followed by the Afrotropical region with 453 species and the Nearctic region with 439 species. The Australasian and Neotropical regions each have 328 and 333 recorded species, respectively, while the Oriental region has 271. The vast majority of non-marine ostracods (89.8%) are endemic to one zoogeographical region, while only six species are found in six or more regions. We also present an additional list with 'uncertain species', which have neither been redescribed nor re-assessed since 1912, and which are excluded from the main list; a list of taxonomic changes presented in the present paper; a table with the number of species and % per family; and a table with numbers of new species described in the 20-year period between 1998 and 2017 per zoogeographical region. Two figures visualize the total number of species and endemic species per zoogeographical region, and the numbers of new species descriptions per decade for all families and the three largest families since 1770, respectively

    Kuwae (~ 1425 A.D.) : the forgotten caldera

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    Dans la partie centrale de Vanuatu, une légende traditionnelle raconte que jadis les îles de Tongoa et d'Epi faisaient partie d'une grande terre, Kuwae, détruite en partie durant un événement cataclysmique d'origine volcanique. Il en résulta la formation d'une caldeira sous-marine ovale, longue de 12 Km et large de 6 Km, avec deux bassins distincts d'une surface totale d'environ 60 Km2. (Résumé d'auteur

    A subjective global checklist of the extant non-marine Ostracoda (Crustacea)

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    We present an updated, subjective list of the extant, non-marine ostracod genera and species of the world, with their distributions in the major zoogeographical regions, as well as a list of the genera in their present hierarchical taxonomic positions. The list includes all taxa described and taxonomic alterations made up to I July 2018. Taxonomic changes include 17 new combinations, 5 new names, I emended specific name and 11 new synonymies (1 tribe, 4 genera, 6 species). Taking into account the recognized synonymies, there are presently 2330 subjective species of non-marine ostracods in 270 genera. The most diverse family in non-marine habitats is the Cyprididae, comprising 43.2% of all species, followed by the Candonidae (29.0%), Entocytheridae (9.1%) and the Limnocytheridae (7.0%). An additional 13 families comprise the remaining 11.8% of described species. The Palaearctic zoogeographical region has the greatest number of described species (799), followed by the Afrotropical region with 453 species and the Nearctic region with 439 species. The Australasian and Neotropical regions each have 328 and 333 recorded species, respectively, while the Oriental region has 271. The vast majority of non-marine ostracods (89.8%) are endemic to one zoogeographical region, while only six species are found in six or more regions. We also present an additional list with 'uncertain species', which have neither been redescribed nor re-assessed since 1912, and which are excluded from the main list; a list of taxonomic changes presented in the present paper; a table with the number of species and % per family; and a table with numbers of new species described in the 20-year period between 1998 and 2017 per zoogeographical region. Two figures visualize the total number of species and endemic species per zoogeographical region, and the numbers of new species descriptions per decade for all families and the three largest families since 1770, respectively
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