Pulse dispersion for single-mode operation of multimode cladded optical fibres

Pulse dispersions as low as 0.4 ns/km have been measured in multimode cladded fibres at a normalised frequency V = 125 and for a constant bend radius of 5.5cm. Particularly when the number of launched modes is small, the pulse dispersion, as well as the polarisation and angular width of the output beam, are strong functions of the degree of mode conversion

Dispersion in low-loss liquid-core optical fibres

Measurements of pulse dispersion in liquid-core multimode fibres have been made for different fibre curvatures and core diameters. The results indicate the presence of mode-conversion effects, and a mode-filtering mechanism is demonstrated with a probing beam of narrow angular width. By measuring transmission loss as a function of angle of incidence, the loss in the cladding material is obtained

Do you want to bet? The prevalence of problem gambling amongst athletes in the UK

This presentation was given as part of the 2011 London Workshop on Problem Gambling: Theory and (Best) Practice by Dr Daniel Rhind from the Sports Sciences subject area at Brunel University. The workshop was organised by Professor Fernand Gobet and Dr Marvin Schiller and hosted by Brunel University on the 13th September 2011

Optical fibres and the Goos-Hanchen shift

It is shown, and confirmed experimentally, that, despite the existence of the Goos-Hanchen shift, the propagation delay of a ray in a multimode cladded fibre is given to a very good approximation by simple ray theory

Radiation from curved single-mode fibres

A study of propagation in curved single-mode fibres shows that the transmission loss increases sharply below a critical bend radius. However the radiation does not leak away uniformly with distance but in a series of discrete well-defined rays

Processes underlying the nutritional programming of embryonic development by iron deficiency in the rat

Peer reviewedPublisher PD

The effect of maternal iron deficiency on zinc and copper levels and on genes of zinc and copper metabolism during pregnancy in the rat

Fe deficiency is relatively common in pregnancy and has both short- and long-term consequences. However, little is known about the effect on the metabolism of other micronutrients. A total of fifty-four female rats were fed control (50 mg Fe/kg) or Fe-deficient diets (7·5 mg/kg) before and during pregnancy. Maternal liver, placenta and fetal liver were collected at day 21 of pregnancy for Cu and Zn analysis and to measure expression of the major genes of Cu and Zn metabolism. Cu levels increased in the maternal liver (P=0·002) and placenta (P=0·018) of Fe-deficient rats. Zn increased (P&lt;0·0001) and Cu decreased (P=0·006) in the fetal liver. Hepatic expression of the Cu chaperones antioxidant 1 Cu chaperone (P=0·042) and cytochrome c oxidase Cu chaperone (COX17, P=0·020) decreased in the Fe-deficient dams, while the expression of the genes of Zn metabolism was unaltered. In the placenta, Fe deficiency reduced the expression of the chaperone for superoxide dismutase 1, Cu chaperone for superoxide dismutase (P=0·030), ceruloplasmin (P=0·042) and Zn transport genes, ZRT/IRT-like protein 4 (ZIP4, P=0·047) and Zn transporter 1 (ZnT1, P=0·012). In fetal liver, Fe deficiency increased COX17 (P=0·020), ZRT/IRT-like protein 14 (P=0·036) and ZnT1 (P=0·0003) and decreased ZIP4 (P=0·004). The results demonstrate that Fe deficiency during pregnancy has opposite effects on Cu and Zn levels in the fetal liver. This may, in turn, alter metabolism of these nutrients, with consequences for development in the fetus and the neonate.</p

Factsheet No. 10 Summer 2020

The portrait presented in this fact sheet is the result of extensive and non-exhaustive research conducted between March 23 and May 17, 2020. Two independent Internet searches were conducted to gather all available information related to gambling, online gambling and the COVID-19 pandemic. Since few studies have been published to date on gambling and the specific context of the health crisis, the information collected is limited to material that is accessible and available on the web at the time of data collection

International collaboration in radiography research

This journal guest editorial makes a case for international collaboration in radiography research