Chameleon Fields: Awaiting Surprises for Tests of Gravity in Space

We present a novel scenario where a scalar field acquires a mass which depends on the local matter density: the field is massive on Earth, where the density is high, but is essentially free in the solar system, where the density is low. All existing tests of gravity are satisfied. We predict that near-future satellite experiments could measure an effective Newton's constant in space different than that on Earth, as well as violations of the equivalence principle stronger than currently allowed by laboratory experiments.Comment: 4 pages, 2 figures. v2: expanded thin-shell discussion. v3: added 2 figures showing numerical results that confirm thin-shell effec

‘I don't think I can catch it’: women, confidence and responsibility in football coach education

Whilst women’s participation in sport continues to increase, their presence remains ideologically challenging given the significance of sport for the construction of gendered identities. As a hegmonically masculine institution, leadership roles across sport remain male-dominated and the entry of women into positions of authority (such as coaching) routinely contested. But in powerful male-typed sports, like football, women’s participation remains particularly challenging. Consequently, constructions of gender inequity in coaching were explored at a regional division of the English Football Association through unstructured interviews and coaching course observation. Using critical discourse analysis we identified the consistent re/production of women as unconfident in their own skills and abilities, and the framing of women themselves as responsible for the gendered inequities in football coaching. Women were thereby strategically positioned as deservedly on the periphery of the football category,whilst the organization was positioned as progressive and liberal

Using quasars as standard clocks for measuring cosmological redshift

We report hitherto unnoticed patterns in quasar light curves. We characterize segments of quasars' light curves with the slopes of the straight lines fit through them. These slopes appear to be directly related to the quasars' redshifts. Alternatively, using only global shifts in time and flux, we are able to find significant overlaps between the light curves of different pairs of quasars by fitting the ratio of their redshifts. We are then able to reliably determine the redshift of one quasar from another. This implies that one can use quasars as standard clocks, as we explicitly demonstrate by constructing two independent methods of finding the redshift of a quasar from its light curve.Comment: References added, Published in Phys. Rev. Let

Genetic polymorphism among Cryptosporidium parvum isolates: evidence of two distinct human transmission cycles.

We report the results of molecular analysis of 39 isolates of Cryptosporidium parvum from human and bovine sources in nine human outbreaks and from bovine sources from a wide geographic distribution. All 39 isolates could be divided into either of two genotypes, on the basis of genetic polymorphism observed at the thrombospondin-related adhesion protein (TRAP-C2) locus. Genotype 1 was observed only in isolates from humans. Genotype 2, however, was seen in calf isolates and in isolates from a subset of human patients who reported direct exposure to infected cattle or consumed items thought to be contaminated with cattle faces. Furthermore, experimental infection studies showed that genotype 2 isolates were infective to mice or calves under routine laboratory conditions, whereas genotype 1 isolates were not. These results support the occurrence of two distinct transmission cycles of C. parvum in humans