Color ordering in QCD

We derive color decompositions of arbitrary tree and one-loop QCD amplitudes into color ordered objects called primitive amplitudes. Furthermore, we derive general fermion flip and reversion identities spanning the null space among the primitive amplitudes and use them to prove that all color ordered tree amplitudes of massless QCD can be written as linear combinations of color ordered tree amplitudes of $\mathcal{N}=4$ super Yang-Mills theory.Comment: 45 pages, 11 figure

The Common European Asylum System: Inconsistent, incoherent and lacking credibility

There are two distinct but related issues here: the diverse probabilities of receiving protection in the EU depending on the country in which one makes a claim, and the credibility of decisions that are made. There is currently no European institution implementing these directives or ensuring that criteria are uniformly applied – instead considerable discretion remains at national level, with the result that where one makes one’s claim matters enormously, a fact ignored by the Dublin regulation

Antenna beam-shaping apparatus Patent

Device for improving efficiency of parabolic horn antenna system for linearly polarized signal

Origins of neotropical leafy Hepaticae

The neotropical hepatic flora, predominantly constituted by members of the Jungermanniales and Metzgeriales, includes a disproportionate number of genera which are endemic (over 38) and a number which evidently originated here but have shown slight and in a geological sense, modern dispersal by solitary species. Endemism is confined almost to the Jungermanniales; it is to a large degree of a unique sort: confined to highly apomorphic derivatives, often extremely reduced, sometimes confervoid or thalloid (aside from 'normal' sexual branches). These endemics are derivatives of basically cool-Gondwanalandic suborders, chiefly Lepidoziineae and Cephaloziineae which, in the Antipodes today include a wide range of plesiomorphic taxa. The highest proportion of endemic genera, often stenotypic (1-3 species each) occurs in the upper montane zone: from upper Andean forest to páramo, to the edge of permanent snow and ice; a smaller number occurs at upper elevations of the Guyana Shield, but more occur in the riverine systems that dissect this shield. The taxa found there (i.a., Zoopsidella, Pteropsiella, Schusterolejeunea, Cephalantholejeunea) are among the most apomorphic of all hepatics. The amount of endemism is shown to be higher than in any comparable region of the globe. It is assumed that this is owing to: (a) isolation, exceeding 40 m.y. and probably exceeding 60 m.y.; (b) continuous tectonic activity, preserving the 'raw' and 'pioneer' habitats which are necessary for the survival of 'fugitive', 'shuttle' and other types of pioneer taxa; (c) the antiquity of the Guyana Shield and its riverine system; (d) creation of striking ecological gradients, many biotic islands; (e) fluctuation in extent and degree of isolation of these 'islands', leading to (f) rapid evolution due to genetic drift and perhaps enhanced selection pressures. It is concluded that part of the complexity of the flora is due to preservation of some elements on the old Guyana Shield but most is due to relatively rapid evolution during Tertiary times. A final contributing element has been the fact that movement of the South American plate has been primarily from east to west, so that the relevant land area has not been rafted into regions with very different climatic parameters: the degree of extinction seen in, e.g., India and Australia is not evident here. It is concluded that the amount of endemism seen, and its extreme kinds, 'need' in excess of the 40-60 m.y. time span which seems available. In particular, the large number of high elevation endemics, some (such as Ruizanthus) very isolated, cannot be satisfactorily explained by assuming their evolution in the few million years available since alpine regions were created by the rise of the Andes. It is almost necessary to conclude that limited 'pre-Andes' must have existed and that the ancestors of the isolated taxa seen today in alpine loci in Colombia and Venezuela originated elsewhere. The other side of the outlined scenario is that with the near-total isolation of tropical America until the Andes were elevated, and until the Pliocene connection to North America arose, one would expect to see few and scattered intruders from cool-Gondwanalandic areas and from Laurasia. The modern flora reflects exactly this

Patrologia Latina

The Patrologia Latina Database offers 221 volumes of works written by the Latin Fathers. It is the extraordinary achievement of the nineteenth-century scholar and priest, Jacques-Paul Migne. It covers the works of the Latin Fathers from Tertullian around 200 a.d. to the death of Pope Innocent III in 1216 and contains the most influential works of late ancient and early medieval theology, philosophy, history, and literature. This review looks at the user interface and content details in this unique database offered by ProQuest