Clinical profiles of post-load glucose subgroups and their association with glycaemic traits over time: an IMI-DIRECT study

Aim To examine the hypothesis that, based on their glucose curves during a seven-point oral glucose tolerance test, people at elevated type 2 diabetes risk can be divided into subgroups with different clinical profiles at baseline and different degrees of subsequent glycaemic deterioration.Methods We included 2126 participants at elevated type 2 diabetes risk from the Diabetes Research on Patient Stratification (IMI-DIRECT) study. Latent class trajectory analysis was used to identify subgroups from a seven-point oral glucose tolerance test at baseline and follow-up. Linear models quantified the associations between the subgroups with glycaemic traits at baseline and 18 months.Results At baseline, we identified four glucose curve subgroups, labelled in order of increasing peak levels as 1-4. Participants in Subgroups 2-4, were more likely to have higher insulin resistance (homeostatic model assessment) and a lower Matsuda index, than those in Subgroup 1. Overall, participants in Subgroups 3 and 4, had higher glycaemic trait values, with the exception of the Matsuda and insulinogenic indices. At 18 months, change in homeostatic model assessment of insulin resistance was higher in Subgroup 4 (beta = 0.36, 95% CI 0.13-0.58), Subgroup 3 (beta = 0.30; 95% CI 0.10-0.50) and Subgroup 2 (beta = 0.18; 95% CI 0.04-0.32), compared to Subgroup 1. The same was observed for C-peptide and insulin. Five subgroups were identified at follow-up, and the majority of participants remained in the same subgroup or progressed to higher peak subgroups after 18 months.Conclusions Using data from a frequently sampled oral glucose tolerance test, glucose curve patterns associated with different clinical characteristics and different rates of subsequent glycaemic deterioration can be identified.Molecular Epidemiolog

Radar observations of magnetospheric activity during extremely quiet solar wind conditions

During a period of extremely quiet solar wind conditions from 8 to 10 March 1997, strong activity was observed by the Southern Hemisphere Auroral Radar Experiment Super Dual Auroral Radar Network radars in the Antarctic premidnight ionosphere. This activity took the form of quasiperiodic flow bursts with ionospheric drift velocities exceeding 2 km s−1. Data from the Satellite Experiments Simultaneous with Antarctic Measurements (SESAME) automated geophysical observatories in Antarctica and Defense Meteorological Satellite Program and Polar satellites are used with the radar data to study the convection flow in the southern polar ionosphere at the time of these flow bursts. The study shows that the bursts occurred with an approximate period of 12 min. Their direction was westward, and they were superimposed on a background westward flow. In the premidnight sector this is interpreted as a flow associated with dipolarization of the magnetotail tail field. There is a band of strong particle precipitation associated with the flow bursts. The location suggests that they occur deep in the magnetotail and cannot be associated with any lobe reconnection. They are at a latitude near the region where a viscously driven convection cell is expected to exist, and their sense is that of the return convection flow in such a cell. The results suggest that there is an internal magnetospheric mechanism for sporadic energy release in the magnetotail that need not be associated with changes in solar wind reconnection on the magnetopause

A magnetospheric substorm observed at Sanae, Antarctica

A magnetospheric substorm that occurred at Sanae, Antarctica, on July 27, 1979, was observed by a variety of techniques. A synthesis of the observations is presented, and an attempt made to deduce details of the behavior of the magnetosphere‐ionosphere system during the event. While there was some evidence of a growth phase, it was inconclusive. At the onset there was a rapid change in the tail field, which assumed a more dipolar form, accompanied by Pi 2 oscillations and the precipitation of 6‐keV electrons, with brightening of the auroral arc, auroral‐type sporadic E ionization, and riometer absorption. A positive spike was observed in the D magnetic component, instead of the expected negative one. There was no evidence of the usual westward traveling surge at the beginning of the expansion phase during which the precipitation region, auroral arc, and electrojet moved rapidly poleward, though it may have occurred outside the field of view from Sanae. The Hβ emission increased by a factor of less than 2, whereas the oxygen and nitrogen emissions monitored increased by 3–4. During the recovery phase, phenomena were consistent with a return of the tail field to an elongated form; a very high ratio of 557.7‐nm/630‐nm emissions, exceeding 10, was observed; and the electrojet lagged noticeably behind the photon emission regions

Quest Volume 4 Number 1

Contents: International Polar Year - The South African National Antarctic Programme - Addressing the global issues: The 730-day International Polar Year - The history behind IPY: Southern Ocean hotspots - Underwater disturbances and ocean currents: Predicting South African rainfall - It's not easy!: Polar convergence of art and science - A common mission in Antarctica: STIAS - a centre for African solutions- How to build a creative space for the mind: Historical memory and healing? - Looking to the future: Grappling with complexity - Facing diversity - Seeking a common language of life: Biology examines its interactions - The Mostertsdrift experimental vineyard Pinotage gets better all the time: Viewpoint - Bridging the digital divide - In search of cheap, reliable bandwidth: Science news- Meditation go-ahead; Fine-tune those precision instruments - Communication for Africa - Telephone access; EASSy does it; A wireless option - Carbon emissions worse than expected; Computer users be warned; Red List alert; The good news B Careers interview Work in electrical engineering and in space physics - talks with Pierre Cilliers: Biotechnology and Health: The S& T tourist Travelling companions - Getting around with books: Your questions answered - Understanding planets & beating addictions: The quest for high-temperature superconductivityThe Department of Science and Innovation: Academy of Science of South Afric