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Climate models are useful tools for monthly to decadal prediction of the evolution of climate. This study assesses how CMIP6 models represent soil moisture-latent heat regimes and coupling processes between the land and atmosphere. Metrics considered are terrestrial and atmospheric coupling indices to show the nature and strength of the coupling over Africa, focusing on the March to May (MAM) and June to August (JJA) seasons over East, Central, and West Africa. Characterization of the annual cycle indicates that model biases are highest during the peak of the rainfall season and least during the dry season, while soil moisture biases correspond with rainfall. Models show appreciable sensitivity to regional characteristics; there was model consensus in representing East Africa and the Sahel as regions of limited soil moisture, while major differences were noted in the wet regime over Central Africa. Most CMIP6 models tend to overestimate the strength of the terrestrial and atmospheric coupling pathways over East and Southern Africa. Inter-model differences in coupling indices could be traced to their inter-annual variability rather than the mean biases of the variables considered. These results encourage further advancement of land surface schemes in the next generation of climate models for a better representation of climate over Africa.

Objective To explore relevant literature and policy around the role of the radiographer working within osteoporosis services. Discussion will examine the value of radiographers in these services, as well as current limitations and future opportunities for advancing practice in these domains. Key findings Osteoporosis and fracture prevention are a public health issue that must be addressed to improve patient outcomes following fractures. DXA radiographers currently fulfill an important role in the diagnosis of osteoporosis and collaborative working between radiology and osteoporosis services is to be encouraged. Radiographers are able to extend their role into advanced practice within osteoporosis services such as fracture liaison and rheumatology, they have expert knowledge and experience to bring to these roles and post graduate education can further increase radiographer's expertise in this field. The inability of diagnostic radiographers to become independent prescribers is a current limitation for radiographers working within osteoporosis services. Conclusion The role of the radiographer working within DXA and osteoporosis services is evolving and is an exciting area of advanced practice. Promoting this specialty within radiography may help to improve job satisfaction as well as recruitment and retention rates. As radiographers scope of practice in osteoporosis changes and evolves, it is hoped that current legislation may change to allow independent prescribing for diagnostic radiographers, which can in turn streamline patient pathways and reduce the burden on primary and secondary care.

The Transtheoretical Model has been recently applied to men seeking services at battering intervention and prevention programs (Eckhardt, Babcock, & Homack, 2004; Murphy & Baxter, 1997). This study considers whether women arrested for intimate partner violence differ from male perpetrators in terms of stages of change and processes of change. No gender differences were found regarding stage of change. In general, all individuals presenting for treatment were in the early stages of change. The use of various processes of change was strongly related to stage of change, with individuals in the more advanced stages of change using more behavioral and experiential strategies to become nonviolent. However, except for the use of social liberation strategies, there were no gender differences in the use of the various processes. These findings suggest that the Transtheoretical Model may apply to female perpetrators equally as well as to male perpetrators. Intervention programs designed for male batterers using the Transtheoretical Model may also be helpful in the treatment of women arrested for domestic violence.

The Internet has grown exponentially from its original conception and now takes the form of a vast network of interconnected computers. It encompasses such a wide arena within science that its impact cannot be ignored. This article reviews some of the areas where the Internet is relevant to Clinical Psychology. Three main areas identified and expanded upon are (i) use of the Internet as a communication medium within this domain, (ii) teaching of the discipline, and (iii) use of the Internet as a tool for psychological research. Within these three areas, examples of the applicability of the Internet are discussed as well as its limitations. In summary, use of the Internet within the psychological domain has many advantages and as such should be embraced by the clinical psychologist.

The delivery of oxygen to the wound site is crucial in healing diabetic foot ulcers, and impairment of this process in people with diabetes leads to delayed wound repair. Hyperbaric oxygen therapy works by elevating the plasma oxygen level. Fibroblasts synthesise and modify collagen, and both these activities require relatively high partial pressures of oxygen. Hyperbaric oxygen can promote healing by stimulating fibroblast activity and collagen formation. Increasing oxygen tensions also has a direct and toxic effect on anaerobes, therefore hyperbaric oxygen therapy has a special role in treating diabetic foot infections. Studies on hyperbaric oxygen therapy in general show it to be a beneficial adjunctive therapy for diabetic foot ulcers. However much of the work is anecdotal and more controlled trials are required.

There have been many reports which suggest that in patients with tibiofemoral osteoarthritis, a reduction in joint space is demonstrated better on weight-bearing radiographs taken with the knee in semiflexion than in full extension. The reduction has been attributed to the loss of articular cartilage in the contact area in a semiflexed arthritic knee. None of these studies have, however, included normal knees. We have therefore undertaken a prospective, double-blind, randomised study in order to evaluate the difference in the joint-space of arthroscopically-proven normal tibiofemoral joints as seen on weight-bearing full-extension and 30° flexion posteroanterior radiographs. Twenty-two knees were evaluated and the results showed that there may be a difference of up to 2 mm in the two views. This difference could be attributed to the inherent differential thickness of the articular cartilage in different areas of the femoral and tibial condyles and a change in the areas of contact between them.

International audience; Simultaneous observations from HF radars and the DMSP satellite have been used to relate the ionospheric convection pattern and the nighBide precipitation at the polar cap-auroral zone boundary. The convection is eastward in the poleward part of the radars field of view and predominantly westward at lower latitudes. The DMSP-F9 particle spectrograms exhibit energetic precipitating protons at the poleward edge of an "inverted V". The downward H + flow displays spatial filtering effects with a clear energy-latitude dispersion. Single-particle trajectory simulations in appropriate field models demonstrate that these ions were ejected from the neutral sheet near 120 R E geocentric distance. Most notably, the simulations reveal significant azimuthal dispersion during transport, and the source region in the magnetotail is found to extend over several Earth radii in the dawn-dusk direction, less energetic particles originating duskward of the high-energy ones. The longitudinal spread of the tail source suggests particle precipitation in the ionosphere over at least one hour magnetic local time. Also, as the downflowing protons travel near the lobeward edge of the plasma sheet, the observations suggest that the convection reversal lies inside the boundary layer plasma sheet (PSBL).

A comprehensive, predictive model is presented that describes the flow and distribution of solids within a circulating fluidised bed (CFB). Dense particle sheets or streamers are assumed to fall at the walls, surrounding a rapid dilute suspension upflow. Mechanisms and relationships for interchange of solid particles between the streamers and dilute suspension are given. The fraction of solids reflected internally at the reactor exit and the suspension density at the solids return location constitute the model boundary conditions. Variations with reactor height in axial suspension density, fractional wall coverage by streamers, and renewal rate of solids at the wall are predicted. Although developed primarily for prediction of circulating fluidised-bed combustor operation, the model may be used for other CFB applications. Model results may be incorporated in detailed modelling of bed-to-wall heat transfer. Model relationships utilise data obtained from the University of British Columbia 115 kWth pilot-scale unit. The model's predictive capability was tested against data provided by Studsvik Energy of Sweden obtained from their 2.5 MWth combustor. Good prediction of the Studsvik density profiles was obtained.

Discrete arc structures were identified from EISCAT data on March 11, 1984 which were simultaneously recorded on All-Sky camera pictures from the Kilpisjarvi station in Finland. From the electric field measurements supplied by the tri-static UHF facility, some privileged orientation has been found through the requirement of a uniform tangential electric field across the arc structure, which corresponds to the preferential arc alignment as deduced from camera pictures. Additional fold structures, resolved by the All-Sky camera, develop along the preexisting arcs which still organize the electric field fluctuations in their vicinity.

SUMMARY The effects of oxamyl applied to the seedbed and growing partially resistant potatoes in controlling potato pale cyst-nematode, Globodera pallida, were assessed in eleven field experiments on sandy, peaty and silty loam soils in England from 1986 to 1988. Standardised procedures allowed valid comparisons to be made between data from the three experiments in 1987 and from the seven experiments in 1988. In soil moderately or heavily infested with G. pallida, oxamyl frequently increased tuber yields of susceptible cv. Desiree and of partially resistant potatoes and lessened crude nematode increase (Pf/Pi) significantly at some sites but not at others. Although 2.8 kg oxamyl ha“1 often increased tuber yields significantly, it was significantly less effective than 5.6 kg in controlling G. pallida at one site and at another site G. pallida increased more than in untreated plots. Potatoes partially resistant to G. pallida were more effective that oxamyl in controlling nematode increase at some sites but not at others. Combined use of oxamyl and partially resistant potatoes was generally more effective in controlling G. pallida than either measure alone. As measured by a ‘control coefficient’ (weight of tubers over 40mm diameter (t ha“1) 4-crude nematode increase (Pf/Pi)), the most effective integrated control of G. pallida was obtained by growing cvs Glenna, Morag or Sante in soil treated with 5.6 kg oxamyl ha-1.

The Depression Anxiety Stress Scale (DASS) was designed to efficiently measure the core symptoms of anxiety and depression and has demonstrated positive psychometric properties in adult samples of anxiety and depression patients and student samples. Despite these findings, the psychometric properties of the DASS remain untested in older adults, for whom the identification of efficient measures of these constructs is especially important. To determine the psychometric properties of the DASS 21-item version in older adults, we analyzed data from 222 medical patients seeking treatment to manage worry. Consistent with younger samples, a three-factor structure best fit the data. Results also indicated good internal consistency, excellent convergent validity, and good discriminative validity, especially for the Depression scale. Receiver operating curve analyses indicated that the DASS-21 predicted the diagnostic presence of generalized anxiety disorder and depression as well as other commonly used measures. These data suggest that the DASS may be used with older adults in lieu of multiple scales designed to measure similar constructs, thereby reducing participant burden and facilitating assessment in settings with limited assessment resources.

The MICADO instrument has been built to measure temperature and wind in the E - and F -regions. It employs a thermally stable field-compensated Michelson interferometer to allow wind measurements. During the winter of 1988–1989, the MICADO instrument was operated at Sodankyla (67°22′N, Finland). Measurements were made by observing the O 1 S (low thermosphere) and the O 1 D lines (high thermosphere) emission. Two co-ordinated campaigns were organized with the EISCAT radar, which operated in special modes. Neutral wind and temperature are derived from EISCAT data. Results of the two instruments are shown. The differences between the two sets of results are discussed and show that most of the discrepancy is due to the presence of vertical winds during the observations where the magnetic activity was high.

Objective Recent research by Wetherell et al. investigating the differential response to group-administered cognitive behavior therapy (CBT) for generalized anxiety disorder (GAD) in older adults found that GAD severity, homework adherence, and psychiatric comorbidity predicted statistically significant improvement. The current study investigated whether the presence/absence of cognitive errors on separate domains of the Mini-Mental State Exam (MMSE) predicted baseline differences in symptom severity and improvement following CBT, above and beyond already established predictors. Methods Baseline characteristics were investigated in a sample of 208 older patients diagnosed with GAD. Predictors of treatment response were examined in a subsample of 65 patients who completed CBT and were included in a prior study by Wetherell et al. of response predictors. Results Results from the baseline sample indicated that only subjects who committed an error on the MMSE Working Memory domain exhibited increased severity in anxiety and depressive symptoms. Results from the treatment sample indicated that an error on the MMSE Orientation domain was a significant predictor of outcome at 6-month follow-up, while controlling for previously established predictors. Patients who committed at least one error in this domain showed decreased response relative to patients who committed no errors. Conclusion In this sample of older adults diagnosed with GAD, poor performance on the MMSE Working Memory domain was associated with increased baseline anxiety and depression, while baseline performance differences on the MMSE Orientation domain predicted outcome six months after CBT intervention.

Telephone assessments are commonly used in mental health research and may be especially beneficial in older populations. The current study assessed the psychometric properties of the Penn State Worry Questionnaire (T. J. Meyer, M. L. Miller, R. L. Metzger, & T. D. Borkovec, 1990) and the Beck Depression Inventory--II (A. T. Beck, R. A. Steer, & G. K. Brown, 1996), when administered over the telephone in an older adult population. Results indicate no differences in mean symptom level or internal consistency across two modes of administration. Correlations between the in-person and telephone-administered measures and diagnostic categories suggest adequate validity of the telephone-administered measures. With this demonstrated evidence, the telephone assessment method can be applied in a variety of research and clinical settings.

Mercury is one of a number of pollutants (like dioxins) that persist in the environment and bioaccumulate in the food chain. Because of its toxicity and the potential for bioaccumulation, mercury emissions to the environment are the subject of environmental regulation. US EPA estimates that 87% of the man-made emissions of mercury come from point sources of combustion. There are currently emission limits on mercury from certain categories of combustion sources, including cement kilns and incinerators burning hazardous waste. Cement kilns that do not burn hazardous waste are not subject to these emission standards. However, EPA is currently reviewing the need for emission standards for mercury and other pollutants from cement kilns. In this paper, we review the chemistry of mercury in the cement-making process, methods for measuring mercury in combustion systems and the experience in other industries with controlling mercury emissions from combustion sources. Emphasis is placed on the chemical forms of mercury in the process.

Depersonalisation may be part of a symptom-complex, a primary or a secondary disorder. Optimal methods of measurement and diagnosis have not been established.We assessed 42 patients with primary or secondary depersonalisation, plus psychiatric and non-psychiatric controls using a variety of self-report questionnaire scales including the Beck depression and anxiety Inventories, and one developed by the authors (the Fewtrell Depersonalisation Scale (FDS)). The correlations between the scales and measures of anxiety and depression were calculated, as were sensitivity and specificity against an operational case definition.All the scales were highly correlated. All could distinguish depersonalisation cases from the rest but none could distinguish between primary and secondary depersonalisation disorder. Anxiety and especially depression were correlated with depersonalisation symptoms. The FDS had high sensitivity (85.7%) and specificity (92.3%) which compared favourably with other instruments. Patients with both derealisation and depersonalisation scored the highest on the FDS.Depersonalisation disorder comprises a measurable cluster of symptoms which may be quantified with the help of self-report scales. Primary and secondary forms overlap, with depressed mood a frequent feature.

The Internet has grown exponentially from its original conception and now takes the form of a vast network of interconnected computers. It encompasses such a wide arena within science that its impact cannot be ignored. This article reviews some of the areas where the Internet is relevant to Clinical Psychology. Three main areas identified and expanded upon are (i) use of the Internet as a communication medium within this domain, (ii) teaching of the discipline, and (iii) use of the Internet as a tool for psychological research. Within these three areas, examples of the applicability of the Internet are discussed as well as its limitations. In summary, use of the Internet within the psychological domain has many advantages and as such should be embraced by the clinical psychologist.

International audience; The combination of radial velocities measured by a pair of Super Dual Auroral Radar Network (SuperDARN) HF coherent radars gives, in their common field of view, the velocity vectors in a plane perpendicular to the magnetic field. The standard merging is based on a natural grid defined by the beam intersections, which provides a resolution varying between 90 and 180 km (depending upon the distance to the radars). This allows the description of structures with a typical scale size (L) of the order of 500 km. The present study is devoted to a merging method which takes advantage of individual radar grids to enhance the resolution (L • 200 km). After a brief description of the standard merging method, we define the high-resolution grid and discuss the potential problems which have to be overcome. The first problem concerns the localization of the scattering volume, whereas the second one deals with the independence of the velocity vectors. These two limitations have been addressed in previous studies [Andrd et al., 1997; Barthes et al., 1998]. In the method proposed here, several velocity vectors are determined at each grid point, from which the selection is made by using the hypothesis of minimization of the divergence magnitude. The selected map is the one which minimizes the divergence. The performances are tested and compared to the standard merging algorithm through simulated double vortices. Finally, we apply this method to real data, and show, through two examples, its ability to describe small-scale structures (L m 200 kin).

SummaryIn 12 field experiments in England (1985, 1991 and 1992), on soils infested with potato pale cystnematode (Globodera pallida), oxamyl increased yields of susceptible and partially-resistant potatoes and lessened nematode multiplication at some sites but not others. Attempts to explain these site differences were unsuccessful. In a heavily infested peaty loam, large amounts of aldicarb or oxamyl, smaller amounts of both conjointly or 6·8 kg oxamyl/ha incorporated in the top 10 cm of the soil were needed to prevent G. pallida multiplication on susceptible Wilja potatoes. In three experiments, 1,3-dichloropropene at 250 or 225 1/ha increased tuber yields more than oxamyl did but had little or no effect on G. pallida multiplication. Ethoprophos at 11 kg/ha or fosthiezate at 4 kg/ha lessened G. pallida multiplication on Désirée potatoes in a silt loam soil but not in a peaty loam soil.The multiplication of G. pallida was reliably controlled in ten experiments by partially-resistant Morag or Santé potatoes. Soil population densities of G. pallida were greatly decreased by one or two crops of Cara potatoes uprooted when the first female nematodes were visible on the roots.It is concluded that granular nematicides and 1,3-dichloropropene are best employed to lessen injury to susceptible and partially-resistant potatoes and that G. pallida increase is best controlled by partially-resistant potatoes protected by a nematicide. Soil infestation levels can be decreased rapidly by soil fumigation or trap cropping with Cara potatoes.

International audience; Coherent HF radars at Goose Bay (Labrador) and Schefferville (Quebec) are used to study plasma convection in the high-latitude ionosphere. Maps of the two-dimensional flow pattern are obtained by merging simultaneous sets of radial velocity data, each with a time resolution of a few minutes. From a time sequence of such maps we have separated the changes in flow due to magnetic local time (MLT) variations over the region of observation, from those due to UT time variations. We study in detail the convection in the early morning sector observed on October 15, 1989, when the interplanetary magnetic field (IMF) reversed from southward to northward. This IMF reversal was not associated with a clear response in the nightside convection but rather with several sudden changes, some of which anticipated the B z reversal. We suggest that these changes are associated with delayed and superposed ionospheric responses to previous IMF perturbations, or to local effects. After the IMF reversal from south to north our observations of westward and southwestward velocities in the 71ø-77 ø invariant latitude range are consistent with the earlier simulations for B z > 0 and By < 0. During the period of steady northward IMF after the reversal the convection pattern was observed to reconfigure slowly: a region of large westward velocities progressively moved poleward, while convection in the low-latitude part of the field of view faded away. The time constam of this slow reconfiguration was about 1 hour and varied with MLT, such that it was larger closer to midnight. These data, combined with particle data from successive passes of the DMSP satellites, provide information on the contraction of the polar cap after the IMF B z reversal and on the MLT dependency of the velocity at which this contraction occurs. They show that the polar cap contracts more rapidly in the daytime than in the nightime and more rapidly in the postmidnight sector than in the premidnight sector.

Recent Hospital Transfusion Committee (HTC) audit at the Royal Bournemouth Hospital (RBH) confirmed an allogeneic red cell transfusion rate of 20% for primary Total Knee Replacement (TKR). Current policy at RBH states that when blood stocks reach 67% of normal (amber alert) then surgery with a >20% likelihood of blood transfusion will be cancelled. At current transfusion rates this would include primary TKR. Recent studies have shown a reduction in allogeneic transfusion rates when autologous transfusion drains are utilized. The purpose of this study was to see whether the current rate of allogeneic transfusion could be reduced with the introduction of the CellTransTM Autologous Knee Drainage Blood Transfusion System (ABT) in TKR at RBH. Over a 3 month period all patients undergoing primary, bilateral or revision knee arthroplasty received an ABT. Demographic data was collected from the orthopaedic pre-assessment clinic. Following surgery further data was collected relating to volume of blood loss into the drain, volume of autologous blood re-transfused, units of allogeneic blood required and the transfusion trigger, postoperative haemoglobin levels, infection rates and length of stay in hospital. We then compared this data set with retrospective data. Of 170 patients undergoing knee arthroplasty 141 received the ABT. The data collected was compared retrospectively with 169 patients from the previous 3 month period. We demonstrated a reduction in transfusion rates of 13% for primary TKR, 42% for bilateral TKR and 57% for revision TKR with the use of the ABT. In addition we demonstrated a reduction in total allogeneic blood use (99 units to 26 units) and a reduction in mean length of stay in hospital (8.6 days to 7.5 days) with the ABT. Further analysis of the data collected showed a 46% reduction in the allogeneic transfusion rate and a reduction in total allogeneic blood usage (99 units to 9 units) of anaemic patients presenting for surgery. This study has demonstrated a dramatic reduction in allogeneic blood transfusion rates with the use of the CellTransTM Autologous Blood Transfusion System. We have also shown a reduction in length of stay in hospital. Prior to the study primary total knee replacement would have been cancelled during times of limited blood availability (amber alert). The use of the ABT is good for the patient in reducing the need for allogeneic blood, and in addition has demonstrated a significant cost saving due to the reduced blood usage and potential prevention of cancelled operation lists.

Data from the Kapuskasing and Saskatoon radars of the evolving Super Dual Auroral Radar Network (SuperDARN) HF radar network have been analyzed to study the two-dimensional structure and dynamics of dayside high-latitude ionospheric convection under northward interplanetary magnetic field (IMF) conditions. A period extending from 1600 to 2030 UT (∼0900-1330 MLT) on January 10, 1994, was examined. During this interval, magnetic field data were available from the IMP 8 satellite and indicated moderately stable northward IMF conditions. For the first few hours of observation the By component of the IMF was positive, reasonably steady, and approximately twice the magnitude of Bz. During this interval, the high-latitude convection images obtained with the SuperDARN radars were very similar to the distorted two-cell convection maps for positive By as presented by Heppner and Maynard (1987). At ∼1840 UT, a decrease in By in association with an increase in Bz, led to an extended period with By ≈ Bz. During this second interval the convection patterns were highly variable and even chaotic. Finally, a sharp decrease in the By component at 1914 UT, probably in association with a rotational discontinuity in the solar wind, led to an extended period with By ≪ Bz. During this third interval, the high latitude convection pattern was again stable and exhibited a single counterclockwise rotating vortex consistent with one of the polar cap merging cells proposed by Dungey (1963), Burke et al. (1979), and Reiff and Heelis (1994). The transition to the counterclockwise rotating vortex occurred over a large spatial area within two radar scans (200 s) and appeared to proceed via an equatorward incursion of the vortex into the previous convection configuration. Once this polar cap merging cell was formed, it remained stable for the remainder of the period (∼40 min) that By remained small. Sunward convection was also observed in the polar cap of the conjugate hemisphere at 1932 UT by the DMSP F11 satellite, confirming that both magnetopause and internal reconnection sites were active at that time.

An analysis of several global measures of high-latitude ionospheric electrodynamic activity is undertaken on the basis of results obtained from the Assimilative Mapping of Ionospheric Electrodynamics (AMIE) procedure applied to incoherent scatter radar and ground magnetometer observations for January 18–19, 1984. Different global measures of electric potentials, currents, resistances, and energy transfer from the magnetosphere show temporal variations that are generally well correlated. We present parameterizations of these quantities in terms of the AE index and the hemispheric power index of precipitating auroral particles. It is shown how error estimates of the mapped electric fields can be used to correct the estimation of Joule heating. Global measures of potential drop, field-aligned current, and Joule heating as obtained by the AMIE procedure are compared with similar measures presented in previous studies. Agreement is found to within the uncertainties inherent in each study. The mean potential drop through which field-aligned currents flow in closing through the ionosphere is approximately 28% of the total polar cap potential drop under all conditions during these 2 days. We note that order-of-magnitude differences can appear when comparing different global measures of total electric current flow and of effective resistances of the global circuit, so that care must be exercised in choosing characteristic values of these parameters for circuit-analogy studies of ionosphere-magnetosphere electrodynamic coupling.

The electrical coupling between the high-, middle-, and low-latitude ionospheres during January 17-19, 1984 is examined, using interplanetary and high-latitude magnetic field data together with F region plasma drift measurements from the EISCAT, Sondre Stromfjord, Millstone Hill, Saint-Santin, Arecibo, and Jicamarca incoherent scatter radars. The penetration both the zonal and meridional electric field components of high-latitude origin into the low-latitude and the equatorial ionospheres are studied. The observations in the postmidnight sector are used to compare the longitudinal variations of the zonal perturbation electric field with predictions made from global convection models. The results show that the meridional electric field perturbations are considerably more attenuated with decreasing latitude than the zonal fluctuations. It is concluded that variations in the meridional electric field at low latitudes are largely due to dynamo effects.

Recent analyses of auroral-zone spaced-receiver measurements have shown that the regions where sheetlike irregularities occur are confined to the equatorward portion of the nighttime scintillation zone where the westward and eastward electrojets flow. Poleward of this region, the irregularities are rodlike. For satellites in highly eccentric orbits, the spaced-receiver technique can be used to measure ionospheric drifts. Simultaneous incoherent-scatter radar measurements have revealed two types of F region ionization enhancements that are believed to be the source regions of persistent scintillation features on polar satellite transmissions. One type is found at the equatorward edge of the diffuse aurora and can persist for more than 10 hours. More dynamic structures often occur in pairs, which suggests an association with ‘inverted-V’ precipitation events. Radar data have also revealed large-scale east-west structure in the poleward enhancements.

Preliminary results are presented on the nature of a distinct class of sub-km high latitude irregularities which can create localized regions of near saturated VHF and fairly intense UHF scintillations in the nighttime auroral F-region. The unique feature of this class of irregularities is that it is associated not with large scale (several tens of km) organized density gradients in the F-region but with velocity shears with shear gradient scale lengths ∼10km. The presence of velocity shears was established by EISCAT ion drift measurements, continuous STARE measurements of electron drift and the in-situ ion drift measurements from the HILAT satellite. Analytical and numerical simulation studies of velocity shear driven Kelvin-Helmholtz type plasma instabilities are necessary to elucidate the generation mechanism of this class of irregularities.

High-time resolution data from the two Iceland SuperDARN HF radars show very strong nightside convection activity during a prolonged period of low geomagnetic activity and northward interplanetary magnetic field (IMF). Flows bursts with velocities ranging from 0.8 to 1.7 km/s are observed to propagate in the sunward direction with phase velocities up to 1.5 km/s. These bursts occur over several hours of MLT in the 20:00–01:00 MLT sector, in the evening-side sunward convection. Data from a simultaneous DMSP pass and POLAR UVI images show a very contracted polar cap and extended regions of auroral particle precipitation from the magnetospheric boundaries. A DMSP pass over the Iceland-West field-of-view while one of these sporadic bursts of enhanced flow is observed, indicates that the flow bursts appear within the plasma sheet and at its outward edge, which excludes Kelvin-Helmholtz instabilities at the magnetopause boundary as the generation mechanism. In the nightside region, the precipitation is more spot-like and the convection organizes itself as clockwise U-shaped structures. We interpret these flow bursts as the convective transport following plasma injection events from the tail into the night-side ionosphere. We show that during this period, where the IMF clock angle is around 70°, the dayside magnetosphere is not completely closed.Key words. Ionosphere (Auroral ionosphere; Ionospheremagnetosphere interactions; Particle precipitation)

Between May 1981 and June 1982 an intensive campaign of 33 coordinated observations was carried out using the three incoherent-scatter radars capable of probing the auroral zone. During this period the groups operating the Dynamic Explorer satellites and the STARE radar made special efforts to acquire data coincident with the radar observations. The objective of these MITHRAS experiments and subsequent analysis is to further our understanding of the interactions of the magnetosphere, the ionosphere, and the thermosphere, with special emphasis on local time/universal time variations. Three experimental modes with different time resolution and spatial coverage were used to examine different aspects of these interactions. The analysis of the extensive data set involves collaboration among groups of experimenters as well as between experimenters and theoreticians.