Photon mixing in universes with large extra-dimensions

In presence of a magnetic field, photons can mix with any particle having a two-photon vertex. In theories with large compact extra-dimensions, there exists a hierachy of massive Kaluza-Klein gravitons that couple to any photon entering a magnetic field. We study this mixing and show that, in comparison with the four dimensional situation where the photon couples only to the massless graviton, the oscillation effect may be enhanced due to the existence of a large number of Kaluza-Klein modes. We give the conditions for such an enhancement and then investigate the cosmological and astrophysical consequences of this phenomenon; we also discuss some laboratory experiments. Axions also couple to photons in the same way; we discuss the effect of the existence of bulk axions in universes with large extra-dimensions. The results can also be applied to neutrino physics with extra-dimensions.Comment: 41 pages, LaTex, 6 figure

Corrigendum to Temperature and Precipitation Affect Steer Weight Gains Differentially by Stocking Rate in Northern Mixed-Grass Prairie (Rangeland Ecology & Management (2013) 66 (438-444))

The Rangeland Ecology & Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information

Improving Cattle Nutrition on the Great Plains with Shrubs and Fecal Seeding of Fourwing Saltbush

Two in vitro trials were conducted for estimates of dietary percentage of fourwing saltbush (Atriplex canescens; FS) or winterfat (Krascheninnikovia lanata; WF) for improved dietary digestibility when cattle graze mature cool-season grass. Three in vitro trials were conducted to estimate percentage of FS and WF seeds that could survive passage through the bovine gastro-intestinal tract (GIT) with potential for fecal seeding. Mixtures of FS and mature smooth bromegrass (Bromus inermis; SB) or WF and SB had greater apparent digestibility than SB alone (P < 0.0001). There were positive linear relationships (r2 ≥ 0.93) between the amount of each shrub in digested mixtures and digestibility. Similar relationships were observed with mixtures of FS and mature Altai wildrye (Leymus angustus). Germination of Dakota FS seeds in the first trial, incubated for 24 or 48 h, was 55% and 47%, respectively, with no difference in germination of seeds for the 24- and 48-h incubations (P = 0.26), but more seeds germinated if incubated versus not (P ≤ 0.002). Germination of Utah FS seeds, which were incubated for 24 or 48 h with high-, medium-, or low-quality forage, averaged 9% and 8%, respectively. Length of incubation, forage quality, and their interaction did not influence germination (P ≥ 0.45). Germination of nonincubated Utah FS seeds was 21% and greater than for incubated seeds (P = 0.004). Average germination of WF seeds was 0.6% and 0.1% for 24- and 48-h incubations, respectively, with incubation length, forage quality, and their interaction not significant (P ≥ 0.31). Nonincubated WF seeds had greater germination (42%) than incubated seeds (P < 0.0001). Results from the third trial were confirmatory for Dakota FS seed. FS and WF can improve diet quality of grazing cattle in late summer through winter, and some FS seeds have potential for fecal seeding. © 2015, Elsevier Inc. All rights reserved.The Rangeland Ecology & Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information