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

Combined EISCAT radar and optical multispectral and tomographic observations of black aurora

Black auroras are recognized as spatially well-defined regions within a uniform diffuse auroral background where the optical emission is significantly reduced. Black auroras typically appear post-magnetic midnight and during the substorm recovery phase, but not exclusively so. We report on the first combined multimonochromatic optical imaging, bistatic white-light TV recordings and incoherent scatter radar observations of black aurora by EISCAT of the phenomenon. From the relatively larger reduction in luminosity at 4278 Å than at 8446 Å we show that nonsheared black auroras are most probably not caused by downward directed electrical fields at low altitude. From the observations, we determine this by relating the height and intensity of the black aurora to precipitating particle energy within the surrounding background diffuse aurora. The observations are more consistent with an energy selective loss cone. Hence the mechanism causing black aurora is most probably active in the magnetosphere rather than close to Earth

Case study of the development of polar stratospheric clouds using bistatic imaging

International audienceThe formation of polar stratospheric clouds (PSCs) is closely related to wave activity on different scales since waves propagating into the stratosphere perturb the temperature profile. We present here a case study of the development of visible PSCs (mother-of-pearl clouds), appearing at the polar vortex edge on 9 January 1997, under-taken by means of ground-based cameras. It is shown that the presence of stratospheric clouds may be detected semi-automatically and that short-term dynamics such as altitude variations can be tracked in three dimensions. The PSC field showed distinct features separated by approximately 20 km, which implies wave-induced temperature variations on that scale. The wave-induced characteristics were further emphasised by the fact that the PSCs moved within a sloping spatial surface. The appearance of visible mother-of-pearl clouds seems to be related to leewave-induced cooling of air masses, where the synoptic temperature has been close to (but not necessarily below) the threshold temperatures for PSC condensation

Energy and flux variations across thin auroral arcs

Two discrete auroral arc filaments, with widths of less than 1 km, have been analysed using multi-station, multi-monochromatic optical observations from small and medium field-of-view imagers and the EISCAT radar. The energy and flux of the precipitating electrons, volume emission rates and local electric fields in the ionosphere have been determined at high temporal (up to 30 Hz) and spatial (down to tens of metres) resolution. A new time-dependent inversion model is used to derive energy spectra from EISCAT electron density profiles. The energy and flux are also derived independently from optical emissions combined with ion-chemistry modelling, and a good agreement is found. A robust method to obtain detailed 2-D maps of the average energy and number flux of small scale aurora is presented. The arcs are stretched in the north-south direction, and the lowest energies are found on the western, leading edges of the arcs. The large ionospheric electric fields (250 mV m?1) found from tristatic radar measurements are evidence of strong currents associated with the region close to the optical arcs. The different data sets indicate that the arcs appear on the boundaries between regions with different average energy of diffuse precipitation, caused by pitch-angle scattering. The two thin arcs on these boundaries are found to be related to an increase in number flux (and thus increased energy flux) without an increase in energ

Results from the intercalibration of optical low light calibration sources 2011

Following the 38th Annual European Meeting on Atmospheric Studies by Optical Methods in Siuntio in Finland, an intercalibration workshop for optical low light calibration sources was held in Sodankylä, Finland. The main purpose of this workshop was to provide a comparable scale for absolute measurements of aurora and airglow. All sources brought to the intercalibration workshop were compared to the Fritz Peak reference source using the Lindau Calibration Photometer built by Wilhelm Barke and Hans Lauche in 1984. The results were compared to several earlier intercalibration workshops. It was found that most sources were fairly stable over time, with errors in the range of 5–25%. To further validate the results, two sources were also intercalibrated at UNIS, Longyearbyen, Svalbard. Preliminary analysis indicates agreement with the intercalibration in Sodankylä within about 15–25%.publishedVersio