Sublimation crystallisation and polymorph stability

International audienc

Vaginal yeasts in the era of "over the counter" antifungals

OBJECTIVE: To establish whether there has been any rise in the prevalence of non-albicans Candida species isolated from vaginal swabs since the introduction of “over the counter” antifungal treatments. METHOD: A retrospective review looking at all positive vaginal yeast isolates collected from women attending one genitourinary medicine clinic during the 6 year period from 1993 to 1998 inclusive. All positive vaginal yeast isolates were included, regardless of whether or not the patients were symptomatic. Isolates from HIV positive women were excluded from the analysis. RESULT: No increase in non-albicans vaginal yeast isolates was shown during the period studied. The proportion of non-albicans yeasts remained constant at approximately 5% of the total yeasts isolated. The most common non-albicans yeast isolated was C glabrata. CONCLUSION: There is no evidence from this study to suggest that the increasing use of “over the counter” antifungal treatment has selected for atypical, possibly inherently azole resistant, strains of vaginal yeasts in HIV seronegative women

A constant travel time budget? In search for explanations for an increase in average travel time

Recent research suggests that during the past decades the average travel time of the Dutch population has probably increased. However, different datasources show different levels of increase. Possible causes of the increase in average travel time are presented here. Increased incomes have probablyresulted in an increase in both costs and benefits of travel. The increase in travel time may also be due to benefits having increased more rapidly than costs. Costs may even have decreased due to the increased comfort level of cars and increased opportunities offered to make double use of one's time(e.g. working in a train)

Topological Pressure-Temperature State Diagram of the Crystalline Dimorphism of 2,4,6-trinitrotoluene

International audienc

Disappearing Conglomerates

International audienc

A stochastic model of congestion caused by speed differences

The authors study interaction on a two-lane road between the trips of two types of drivers who differ by their desired speeds. The difference in desired speeds causes congestion, because slow vehicles force fast vehicles to reduce their speed. Results for this type of congestion with respect to tolling are very different from those of the classic Pigou--Knight model, where the marginal external costs are an increasing function of the number of road users. In our model we find the opposite result: the marginal external costs of slow vehicles are a decreasing function of the number of slow vehicles. This leads to rather different policy recommendations

Cavitating Langmuir Turbulence in the Terrestrial Aurora

Langmuir cavitons have been artificially produced in the earth's ionosphere, but evidence of naturally-occurring cavitation has been elusive. By measuring and modeling the spectra of electrostatic plasma modes, we show that natural cavitating, or strong, Langmuir turbulence does occur in the ionosphere, via a process in which a beam of auroral electrons drives Langmuir waves, which in turn produce cascading Langmuir and ion-acoustic excitations and cavitating Langmuir turbulence. The data presented here are the first direct evidence of cavitating Langmuir turbulence occurring naturally in any space or astrophysical plasma.Comment: 4 pages, 4 figures, published in PRL on 9 March 2012 http://link.aps.org/doi/10.1103/PhysRevLett.108.10500

On the relationship between travel time and travel distance of commuters. Reported versus network travel data in the Netherlands

This paper gives a detailed empirical analysis of the relationships between different indicators of costs of commuting trips by car: difference as the crow flies, shortest travel time according to route planner, corresponding travel distance, and reported travel time. Reported travel times are usually rounded in multiples of five minutes. This calls for special statistical techniques. Ignoring the phenomenon of rounding leads to biased estimation results for shorter distances. Rather surprisingly, the distance as the crow flies and the network distance appear to be slightly better proxies of the reported travel time compared with the shortest network travel time as indicated by the route planner. We conclude that where actual driving times are missing in commuting research the other three indicators mentioned may be used as proxies, but that the following problems may emerge: actual travel times may be considerably higher than network times generated by route planners, and the average speed of trips increases considerably with distance, implying an overestimate of travel time for long distance commuters. The only personal feature that contributes significantly to variations in reported travel times is gender: women appear to drive at lower average speeds according to our data. As indicated in the paper this may be explained by the differences in the car types of male and female drivers (females drive older and smaller cars) as well as higher numbers of stops/trip chaining among women. A concise analysis is carried out for carpoolers. Car-pooling leads to an increase in travel time of some 17% compared with solo drivers covering the same distance. In the case of car poolers, the above mentioned measures appear to be very poor proxies for the actual commuting times