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Interpersonal interactions rely on various communication channels, both verbal and non-verbal, through which information regarding one’s intentions and emotions are perceived. Here, we investigated the neural correlates underlying the visual processing of hand postures conveying social affordances (i.e., hand-shaking), compared to control stimuli such as hands performing non-social actions (i.e., grasping) or showing no movement at all. Combining univariate and multivariate analysis on electroencephalography (EEG) data, our results indicate that occipito-temporal electrodes show early differential processing of stimuli conveying social information compared to non-social ones. First, the amplitude of the Early Posterior Negativity (EPN, an Event-Related Potential related to the perception of body parts) is modulated differently during the perception of social and non-social content carried by hands. Moreover, our multivariate classification analysis (MultiVariate Pattern Analysis - MVPA) expanded the univariate results by revealing early (

Discrepancies between sensory predictions and action outcome are at the base of error coding. However, these phenomena have mainly been studied focusing on individual performance. Here, we explored prediction errors during a human-avatar motor interaction and focused on both the classical frontal error-related brain responses and the activity of the action observation network. Our motor interaction paradigm required healthy individuals to synchronize their reach-to-grasp movements with those of a virtual partner in conditions that did (Interactive) or did not require (Cued) movement prediction and adaptation to the partner’s actions. Crucially, in 30% of the trials the virtual partner suddenly and unpredictably changed its movement trajectory thereby violating the human participant’s expectation. These changes elicited error-related neuromarkers (ERN/Pe - Theta/Alpha modulations) over fronto-central electrodes mainly during the Interactive condition. Source localization and connectivity analyses showed that the frontal Theta activity induced by violations of the expected interactive movements was in phase with occipito-temporal Theta activity. These results expand current knowledge about the neural correlates of on-line motor interactions linking the frontal error-monitoring system to visual, body motion-related, responses.

In this paper we present the measurements and interpretations of the Tethered Magnetometer (TEMAG) experiment flown on the Tethered Satellite Mission Reflight TSS-IR. Data were taken during the active operating phase when current steps of variable amplitude were injected along the electrically conducting tether. The magnetic field shows clear signatures in the components and amplitude, dependent upon the orientation of the magnetometer boom with respect to the spacecraft ram velocity vector. In the eight events studied, current effects could be observed in the magnetic field data only when the boom was pointing toward the ram side hemisphere of the satellite. The picture emerging from the observed results suggests the formation of a current sheet on the ram side, possibly associated with the aerodynamic shock and compression of the geomagnetic field ahead of the satellite. Although the limited data do not allow full description of the phenomenology, they place important observational constraints on any theoretical model.

We have developed and examined a new regional geomagnetic index AES-80, defined similarly to the classical auroral electrojet AE index, using data from five Antarctic stations located at corrected geomagnetic latitudes about 80 °S. Because only sparse ground-based information can be derived from auroral latitudes in the Southern Hemisphere, and because no index comparable to AE can be constructed from locations in the south, the possibility of using AES-80 as a measure of high latitudes and polar cap activity is investigated. As a global average activity level indicator, it is found that in general AES-80 gives results rather similar to the classical AE index. However AES-80 provides a more robust measure of the occurrence of high-latitude geomagnetic activity.Key words. Magnetospheric physics (auroral phenomena; polar cap phenomena).

During the TSS-1R flight, conditions occurred under which very intense currents flowed through the tether wire system. The effect of these currents during the active phases of operation was clearly seen by the TEMAG sensor assembly located on the short, fixed satellite boom. Magnetic signatures appeared on the field components parallel to the boom and to the spin axis with a strong peak when the boom points closer to the ram direction. While a toroidal current flowing on the ram side of the plasma sheath may explain the main features seen by the TEMAG outboard sensor, further studies are needed for the physical interpretation of the complex electrodynamic interactions of the TSS-ionosphere system.

On October 6, 1979, the low-altitude polar-orbiting satellites DMSP-F2 and-F4 crossed the auroral electron precipitation region in the opposite hemispheres at nearly the same universal time (UT) and in the same magnetic local-time (MLT) sector near midnight. Three pairs of such nearly simultaneous conjugate crossings took place during a period of enhanced magnetic activity and strongly turning northward or southward of the interplanetary magnetic field (IMF). These conjugate observations allowed the study, with time resolution better than six minutes, of the variation, in response to directional changes of the interplanetary magnetic field, of the latitudinal position and width of the auroral regions; these are believed to map the central plasma sheet (CPS) and boundary plasma sheet (BPS). During the equatorward expansion of the whole auroral electron precipitation region, its latitudinal width is observed to decrease markedly when the IMF turns from a northern to a southern direction. In particular, a different response of the equatorward boundary of the auroral oval with respect to the poleward boundary results from the observations, showing that the speed of the equatorward expansion of the equatorward boundary, measured at a temporal resolution of less than 6 minutes, is lower than the speed of the poleward boundary. The BPS/CPS boundary moves coherently with the southward turning of the IMF, with intermediate speed. It follows that the latitudinal width of the poleward part of the auroral region, assumed to map the boundary plasma sheet, decreases more dramatically than the width of the equatorward part of the region mapping the central plasma sheet. These findings could be explained in terms of changes of the total open magnetic flux. Actually, the equatorward shift of the poleward boundary of the auroral oval and the subsequent dramatic thining of the BPS region seem to be the consequence of a larger number of geomagnetic flux line interconnected with the IMF during a southward IMF condition.

This paper is an overview of the project TSS-1 and of its basic electrodynamic-science objectives. To this purpose, we first discuss the electrodynamics of conducting tethers in orbit and, secondly, provide a detailed description of the project and its payload. We also add, in the final part of the paper, a short account of the first TSS-1 flight which took place in August 1992.

A brief overview of the magnetospheric research activity carried out recently at IFSI CNR is given in the following.

International audience; The Gattini cameras are two site testing instruments for the measurement of optical sky brightness, large area cloud cover and auroral detection of the night sky above the high altitude Dome C site in Antarctica. The cameras have been operating since installation in January 2006 and are currently at the end of the first Antarctic winter season. The cameras are transit in nature and are virtually identical, both adopting Apogee Alta CCD detectors. By taking frequent images of the night sky we obtain long term cloud cover statistics, measure the sky background intensity as a function of solar and lunar altitude and phase and directly measure the spatial extent of bright aurora if present and when they occur. The full data set will return in December 2006 however a limited amount of data has been transferred via the Iridium network enabling preliminary data reduction and system evaluation. An update of the project is presented together with preliminary results from data taken since commencement of the winter season.

In this paper, we present a limit on total radiated power for emission measurements in reverberation chambers. This total radiated power limit is intended to be equivalent to the FCC maximum E-field for emission testing over a ground plane.

Ferromagnetic thin films can be used to improve the shielding effectiveness (SE) of plastic substrates against the electromagnetic field in the radio frequency range. In order to obtain good shielding performances, the ferromagnetic thin film is required to have a high AC permeability over the spectral range of interest. Actually, the magnetic permeability of common ferromagnetic alloys and ferrites decreases very rapidly to one above a few hundred megahertz. In this work, Fe-Hf-O thin films have been deposited on plastic substrates by ion beam co-sputtering of two Fe and HfO/sub 2/ adjacent targets. Multi-layered structures containing the ferromagnetic film have also been deposited in order to enhance the shielding performance of the coating. The electric conductivity of the layers has been measured by using the four-print probe method. Simulated and measured shielding effectiveness of the films have been compared in order to derive the dispersion characteristics of the ferrite. Good adhesion between the multilayer and the substrate has been observed for both poly-vinyl-chloride and polycarbonate substrates.

The emission patterns from electrically-large objects are complex and require time-consuming spherical scans to determine the emission maximums. A planar cut through the spherical pattern is a relatively easy measurement to make and resembles the techniques used in present EMC emissions and immunity standards. However, a planar cut is likely to miss the maximum emission from a test object. This paper explores how planar cut data can be used to estimate the spherical emissions maximum. Simulated data including both the full spherical radiation pattern and planar cut estimates for a random emitter are presented The key result is that, if planar cut data can be used to accurately approximate the mean radiation power, then directivity estimates for electrically large emitters can be used to accurately predict the maximum emissions. The results presented here have application to emissions and immunity measurements at frequencies above 1 GHz where most objects will be electrically large and have complex emissions and receiving patterns.

[1] On 30 November 1999, the Italian all-sky camera ITACA (Ny-Alesund, Svalbard), observed one of the strongest dayside aurora events occurred during the 1999/2000 winter season. In the postnoon, the red auroral activity was characterized mainly by four quasiperiodic pulsed activations, with brightness, period and latitudinal extent increasing monotonically with time. During this period, the Wind satellite was well positioned upstream in the solar wind and measured a IMF Bz close to zero, together with a constantly negative IMF By ∼ −10 nT. A detailed description of the phenomenon is presented, together with a preliminary analysis of the data. This work underlines that it is difficult to identify, among the parameters usually involved in the solar wind–magnetosphere coupling, the source of the modulation(s) observed in the aurora development.

The authors report a case of renal leiomyosarcoma and a review of the literature, underlining the difficulties of making a correct differential diagnosis with the benign neoplasms of the kidney and in performing correct surgical therapy.

On the basis of ground magnetometer data from 75 northern hemisphere stations and the ionospheric conductivity distribution estimated from Viking satellite observations of auroral images, various electrodynamic quantities in the polar ionosphere are calculated for the April 1, 1986, Coordinated Data Analysis Workshop (CDAW) 9 substorm. Since the Scandinavia and Russia chains of magnetometers were located in the premidnight-midnight sector during this interval and the estimated conductivity distribution is instantaneous, our data set provides us with a unique opportunity to examine some long-standing problems associated with the substorm expansion onset. Several important findings of this study are summarized as follows: (1) Before the expansion onset of the substorm, intensifications of ionospheric currents or the cross-polar cap potential are very weak in this particular example. Both quantities begin to increase notably only with the initiation of the substorm expansion onset. (2) The intensified westward electrojet flows along the poleward half of the enhanced ionospheric conductivity belt in the midnight sector during the expansion phase, while its equatorward half is occupied by a weak eastward electrojet. (3) The Joule heating rate and the energy input rate of auroral particles are quite comparable preceding the expansion onset. During the expansion phase of the substorm, however, Joule heating shows a marked intensification, but the latter increases only moderately, indicating that the Joule dissipation is more effective than auroral particle energy input during substorm times. (4) The Hall currents are not completely divergence-free. The corresponding field-aligned currents show highly localized structures during the maximum epoch of the substorm, with the upward current being located in the region of the steepest conductivity gradient on the poleward side of the westward electrojet in the midnight sector. This is indirect evidence that the so-called imperfect Cowling channel is effective behind the westward traveling surge.

It has become apparent during recent years that global magnetospheric imaging through the detection of energetic neutral atoms (ENA) will be a crucial tool for the advancement of magnetospheric research via remote sensing technique. This report presents model calculations of ENA precipitation as detectable from a satellite orbiting at low altitudes (

The configuration of the magnetic field in the Earth's geomagnetic tail is studied. The results in the lobe region and in the plasma sheet boundary layer region are compared. A systematic enhancement of the By component of the field is detected in the plasma sheet boundary layer with respect to the lobe; this enhancement leads to a lower rate of flaring of the magnetic field lines in the lobe with respect to the plasma sheet boundary layer. This observation is a signature of field aligned currents at the boundary. The direction of such field aligned currents agrees with the nightside region two current system.

The ISEE 1 and ISEE 2 observations of the lobe/mantle and of the plasma sheet region, at distances between 10 and 20 RE downtail during 1978 and 1979, have been examined. Cold, tailward flowing ionospheric O+ streams (at energies between 50 eV/q and 5 keV/q), observed during geomagnetically disturbed periods, have been statistically analyzed. At the crossing between the lobe/mantle region and the plasma sheet the characteristics of the streams change significantly. These changes suggest the action of energization and isotropization processes which accelerate the ionospheric ions and make them a part of the plasma sheet plasma. The region where these processes are observed is assumed here to be the plasma sheet boundary layer. It is shown that the stream flow pattern in the lobe/mantle region is in good agreement with the tail lobe ion spectrometer model for the thermal speed distribution as well as for the flow velocity and density distributions. This agreement also holds in a qualitative sense in the plasma sheet boundary layer; assuming the appropriate electric field configuration; the E×B drift direction along the YGSE axis appears to reverse with respect to what is observed in the lobe/mantle region, in agreement with the assumed reversal of the Z component of the dc electric field at the plasma sheet boundary.

The influence of the Bz and By polarity of the IMF on the location of the dayside regions of precipitating, low energy electrons recorded by the DMSP F-2 satellite, is investigated. The average differential electron flux was determined for 2 months during local summer. It is found that the spatial distributions are similar for electrons in the range from 50 to 183 eV. The region of maximum intensity for Kp⩽ 2+ over the Southern Hemisphere is located on the opposite side of noon from the Northern Hemisphere. The current intensity carried by precipitating electrons in the cusp region agrees with that measured by the TRIAD magnetometer. When the IMF is northward a marked asymmetry of the low energy electron precipitation between positive and negative By cases is observed. For positive By the maximum electron flux occurs between 0800 and 1200 M.L.T.and −76 and −83° M.L.A.T.and for negativeBythe region occurs between 1200 and 1500 M.L.T. and −79 and −82° M.LAT. The dynamical variations associated with substorm activity when the IMF is southward obscure the expected By effect.

The ISEE-1 and ISEE-2 observations of the lobe/mantle region and the plasma sheet boundary layer region at distances between 10 and 20 RE downstream during 1978 and 1979, have been examined. Cold, tailward flowing ionospheric 0+ streams observed during geomagnetically disturbed periods, have been statistically analysed. At the crossing between the lobe/mantle region and the plasma sheet boundary layer region the characteristics of the streams change significantly. These changes suggest the action of energization and isotropization processes which accelerate and make the ionospheric ions a part of the plasma sheet plasma.

A comparison between the quiet-time magnetic-field measurements performed on the GEOS 1 spacecraft in the period May 13, 1977–December 13, 1977 and the predictions of four geomagnetic-field models is presented. For the explored magnetospheric region the best approximation to the GEOS 1 measurements is given by the 1976 Olson and Pfitzer model: the difference between its predictions and the experimental data never exceeds 3 per cent in the absolute value of the field and 3 degrees in the field direction.

The low-altitude polar cusp region observations of precipitating electrons sometimes show the signature of two different plasma regimes; i.e. the electron average energy and total flux assume different values, and at times, the transition is very distinct. We systematically surveyed three months of DMSP satellite precipitating electron data to determine the existence and frequency of occurrence of such distinct structured magnetospheric cusp regions; the relationship of such observations to the orientation of the interplanetary magnetic field to solar wind parameters, and to geomagnetic activity was studied. Over 2000 cusp region observations were analyzed. Only 2% of the observations show two distinct regions with a sharp demarcation; they may be observed in either hemisphere. The frequency of occurrence of the events seems not to depend on the solar wind parameters; such occurrence has a dependence on the IMF orientation and reaches a maximum during moderately disturbed conditions, as indicated by the AE index. In 85% of the cases, the more energetic population is located equatorward of the other population; 62% of these cases show more intense flux in the equatorward region. The other 15% show the more energetic population located poleward of the lower energy population without any relation to the electron flux in the cusp. This study reveals that the polar cusp and boundary layer are sometimes distinguishable at low altitude based on the precipitating electron characteristics.

The EGD Plasma experiment on board of ISEE-2 spacecraft has been able to observe, in the Earth's magnetotail, positive ions flowing tailward. These ions are observed mostly in the evening sector of the magnetosphere during the recovery phase of the main geomagnetic storms and are identified to be O+ ions. Our observations are made above the plasma sheet, in the lobes of the geomagnetic tail or in the boundary layer. The energy of the oxygen ions is observed to vary from 200 to 10000 eV. When the oxygen energy is high enough, also protons are observed at similar flow speeds. The O+ pitch angle distribution is not centered around the magnetic field direction, and often has a conical pattern. The energy of the O+ is also strongly correlated with the magnetic field component Bz, and is a function of local time.

The first simultaneous (within 6 min) observations of the low altitude polar cusp regions in the conjugate hemispheres are reported here based on two events detected by the DMSP-F2 and F 4 satellites within the same geomagnetic local time sector. It is found that the electron spectra in the cusp are identical in the opposing hemispheres. In one case the observed latitudinal location and extent of the cusps are the same at the two hemispheres. However, in the other case the location of the equatorward boundary of the cusp regions differs by about 2° with drastically different spatial features. It is also found that in one of the events the plasma sheet electron precipitation regions overlap with the cusp regions at lower latitude in both hemispheres. The poleward boundary of these overlapping regions is located at the same latitude on either hemisphere, suggesting that this is the latitude of the last closed field line and that the cusp electrons are present on both closed and open magnetic field lines.

Measurements of the intrinsic noise of a second harmonic flux-gate magnetometer have been performed in the 0 Hz to 5 Hz bandwidth. The digital Fourier analysis technique was adopted to extend the spectrum analysis to the very low frequency range. The dependence of the r.m.s. noise on drive current and the frequency spectrum of the noise at the operating drive level have been studied.

The differential particle spectrum of electrons between 50 eV and 20 keV, as measured by the electrostatic analyser on DMSP-F2, is used to identify regions of precipitation in the earth’s polar regions above 800 km altitude. A typical cusplike spectrum is defined by analysis of the DMSP data, compared with published data, and used to locate regions of cusplike precipitation. A comparison between the September 19–21, 1977 stormtime location of such regions and the quiet-time location is discussed. In general, the region of cusplike precipitation is significantly displaced equatorward from its quiet-time location.

Among various techniques to monitor the polar cusp region, the best available way is by using several low-altitude satellites all on the noon-midnight polar orbit to perform particle precipitation measurements. Fortunately, such an opportunity occurred in the USAF Defense Meteorological Satellite Program (DMSP). Two identical satellites had circular orbits in the noon-midnight meridian at ∼ 840 km altitude. Thus the polar cusp regions over both the northern and southern polar regions could be monitored with a temporal resolution of at least once every hour per hemisphere. In this paper, we will summarize recent findings of polar cusp characteristics and dynamics based on DMSP observations.

Interplanetary-plasma data at 1 AU obtained with experiment S-73 on board of HEOS-A during the last week of February 1969, have been analyzed.

The low-frequency (1.7–6.7 mHz) powers of the horizontal componentsH andD recorded at the Antarctic Italian geomagnetic observatory at Terra Nova Bay (geomagnetic coordinates 77.3S, 279.4 E) during the austral summers 1987/1988 and 1989/1990 have been analysed. The activity level is higher during 1989/1990, corresponding to solar maximum, and theD power is always higher than theH one. The daily power distribution shows, for both components, a significative activity enhancement around the magnetic local noon, which more clearly emerges during quiet magnetospheric conditions. Good correlations have been obtained between the low-frequency power and the solar-wind velocity, the IMF standard deviation and theK p index, suggesting that the low-frequency power is linked both to theK-H instability and to the penetration into the magnetosphere of interplanetary turbulence. Correlation coefficients attain minimum values around the magnetic local noon, when the power level is higher.

Anisotropic O/sup +/ ions were frequently observed by the GEOS 2 ion composition experiment in the energy range 4--130 eV, during the CDAW 6 event of March 22, 1979. These observations allow the study of the plasma flow in the electric and magnetic fields as known from data of other experiments in the geosynchronous orbit, in the noon, dusk and midnight sectors. By comparison of these measurements with plasma observations made by the ISEE 2 plasma experiment, at the same local time and a different latitudes, the observation of cold plasma streaming along magnetic field lines from the polar ionosphere to the equatorial magnetosphere is extended from the magnetotail to the near earth equatorial region.

In this study we present a comparison between the properties of the ionospheric ion streams in the Earth's magnetotail and the predictions of a two-dimensional kinetic model for the transport of ionospheric ions from the cleft topside ionosphere into the tail lobes. General agreement is apparent between average data and model with appropriate assumptions for the ionospheric source. The same general features in the topology and similar numerical values of the stream density and velocity appear in the data and in the model predictions. However, variations associated with varying magnetic activity levels do not appear to be well modelled yet. In particular the assumption that magnetospheric activity as represented by the AE index, and the model numerical values of the cross-tail electric field might be simply related to each other does not prove to be satisfactory. Model sophistication and data coverage and organization will have to be improved to study these effects in deeper detail. copyright American Geophysical Union 1988

The structure of the magnetotail plasma sheet-plasma lobe boundary was studied by observing the properties of tailward flowing O+ ion beams, detected by the ISEE 2 plasma experiment inside the boundary during three time periods. The computed value of the north-south electric field component as well as the O+ parameters are shown to change at the boundary. The results are related to other observations made in this region. The O+ parameters and the Ez component behavior are shown to be consistent with that expected from the topology of the electric field lines in the tail as mapped from the ionosphere.

During magnetospheric substorm events, the plasma and ion composition experiments in the ISEE-1 and 2 satellites detected cold ionospheric O+ streams, moving tailwards in the near Earth magnetotail. Flow is parallel to the magnetic field lines, with drift velocity in agreement with the electric field topology obtained by mapping the model ionospheric field along the magnetic field lines. Fluctuations of the flow velocity of the streams can be related to magnetotail movements. Oscillations of the flow direction and speed with periods ranging from 5 to 10 min that suggest the presence of waves are observed. The streams are observed at all distances between 15 and 6 Re from the Earth. When averaged over 360 deg, the streams show up as a low energy peak, superimposed on the distribution of isotropic plasma sheet ions. This double-peak structure of the energy spectrum seems typical of the disturbed plasma sheet.

A set of 118 pairs of nearly simultaneous polar cusp observations over opposite hemispheres, taken by two identically instrumented satellites on orbits that are very close to each other, is used to determine the morphology of the conjugate polar cusps. It is found that the general mirror image picture does not extend to the precision of a fraction of a degree in magnetic latitude (MLAT). Only 54% of the equatorial boundary observations and 32% of the poleward boundary observations are within {+-}1{degrees} of the conjugate location. The influences of the Earth's magnetic dipole tilt, of geomagnetic activity, and of the IMF parameters on the cusp asymmetry are investigated; no unique parameter is found to better organize the conjugacy of the two cusps. Rather, all of these parameters appear to have a slight effect on the relative locations of the opposite polar cusps. The difference in the MLATs between boundaries of conjugate polar cusp regions depends on the latitude of the cusp location. Furthermore, the projection of the boundaries of the polar cusp regions onto the ionosphere does not follow the offset circle that describes the configuration of the average auroral oval.

On day 143, 1978, 2230–2330 UT, the ISEE 2 plasma experiment detected the multiple population frequently found in the mantle and low-latitude boundary layer regions of the magnetotail. This population consisted at this time of ionospheric O+ and H+ mixed with solar wind plasma (typically H+ and He++). A detailed analysis of the low-energy population indicates that it can be further resolved into two distinguishable proton components. The ratio between the oxygen and the proton energies implies that one of the proton populations is of ionospheric origin and flows tailward together with the ionospheric oxygen. The angular distribution of the other proton population and of the He++ suggests a higher-altitude origin, the presence of He++ ions suggesting that this is the solar wind proton component.