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It was almost a decade ago when the first space geodetic project was commenced in the Pannonian- Carpathian-Dinaric (PANCARDI) region with the aim of di- rect measurement of present crustal movements and strain. The most effective space geodetic technique for this purpose turned out to be the Global Positioning System (GPS). Sev- eral countries established their own national GPS network for monitoring crustal deformation. Nowadays stations of global, continental, regional, national and many local net- works operate in the territory of the study area. An overview of these GPS geodynamic programs is given in the first sec- tion, then we analyse the data of the regional and the Hun- garian national program and give short reports from other projects in the PANCARDI region. In our analysis we com- pare the velocities derived from space geodesy with those predicted by the NNR-NUVEL1A model based on geolog- ical and geophysical records. Looking into the intraplate crustal velocities the data show a fairly stable Bohemian Massive (BM) with relative crustal velocities smaller than 1 mm/yr. With reference to the BM in the north, the western part of the Alpine-North Pannonian (ANP) unit is moving to the East (E) with generally 1 mm/yr velocity that increases to more than twice this value towards its westernmost parts. The largest principal strain rate between these tectonic do- mains is a NE-SW oriented contraction ( 8.6±2.5◊10 9 /yr (ppb/yr)) over an approximately 300◊300-km area. Here we observe left-lateral shear rate (97 ±7 ; 10±2 ppb/yr) be- tween the Alpine-North Pannonian unit and the Bohemian Massif. South of the Alpine-North Pannonian unit the com- plex structure of junction of several tectonic domains can be described by northward trending velocities with 1-2 mm/yr north component relative to the ANP unit or the BM. The direction of contraction near the boundary of the Adriatic microplate is NW-SE oriented with magnitude of 8.0±5.3 ppb/yr over an area of 300◊120-km. Here we observe E- W oriented (93 ±13 ) right-lateral shear (12±5 ppb/yr) be- tween the ANP unit and the southernmost sites in the Di- narides and Southern Alps. These imply that the northward moving Adriatic region is presently squeezes out the ANP unit to the East from between the BM and the Adriatic mi- croplate. Except for a couple of sites the eastern section shows no significant velocities yet. It seems likely that the eastward escape is absorbed in the central section of the ANP in the Pannonian basin since no detectable eastward compo- nent found for the site velocities in the eastern, north-eastern part of the ANP unit.

Our report presents a case of Clostridium septicum gas gangrene in an unusual, orbital localization. The predisposing factors are typical: colon tumour and lymphatic malignancy. Most probably bacteria from the intestinal flora entered the bloodstream through the compromised intestinal wall and settled in the orbit resulting in the development of an abscess containing gas. At the site of the gas gangrene, an indolent B cell lymphoma was present. After surgery and antibiotic treatment, the patient healed from the C. septicum infection; but subsequently died as a consequence of the tumour.

Objective:In Hungary, between 2005–2009 around 57% of hypertensive patients did not reach the goal blood pressure (BP).Design and method:In one of the Hypertension Outpatient Clinics of the 1st Department of Medicine Nephrology-Hypertension Center in Szeged 310 patients’ data were analyzed. Means of

Kinetics of the reaction Br + CH2ClBr--CHClBr + HBr (1, -1) were studied experimentally in the forward direction. The absolute reaction kinetics method of laser flash photolysis coupled with Br atom resonance fluorescence detection and three different relative-rate methods with gas-chromatographic analysis were applied to carry out the experiments. The rate constants determined were found to obey the Arrhenius law in the wide temperature range of T = 293-785 K providing the kinetic expression k1 = (2.8 +/- 0.1) x 10(13) exp[-(47.6 +/- 0.3) kJ mol(-1)/RT] cm3 mol(-1) s(-1) (the errors given refer to 1sigma precision). An ab initio direct dynamics method was used to study reaction (1, -1) theoretically. The electronic structure information including geometries, gradients, and force constants was obtained at the MP2 level of theory; and energies were improved at higher theoretical levels. Rate constants were calculated using the canonical variational transition state theory with small-curvature tunneling correction over the temperature range 200-1000 K. Theory substantially underestimates k1 compared to experiment. The agreement was found good with k(-1) reported previously predicting positive temperature dependence. The experimental kinetic parameters were utilized in thermochemical calculations yielding the recommended standard enthalpy of formation of delta(f)H degrees (298) (CHClBr) = (140 +/- 4) kJ mol(-1) (with 2sigma accuracy given).

The primary purpose of the Space VLBI Geodesy Demonstration Experiment (GEDEX) is to test how this new potential space geodetic technique works in practice using data from the first dedicated space VLBI satellite HALCA. Here we present our experience with a test observation made in December 1997. The data flow and pre-processing procedure is outlined. Initial results of preliminary data reduction using GINS, the CNES/GRGS software for analysis of space geodetic technique data, are presented.

Civil users of the NAVSTAR Global Positioning System (GPS) in Hungary occasionally experience interference at the 1575.42-MHz GPS signal frequency. As the application of the GPS technique spreads rapidly in our country, radio frequency interference (RFI) should be considered a serious threat. The new geodetic control network (OG-PSH) in Hungary is based on GPS measurements and incorporates more than 1100 sites. The paper reports the experiences gained during the establishment of the network. Interference sources were tracked to ground-based digital data transmissions for telecommunications, which operate mostly in the Western part of Hungary. Telecommunication regulations exceptionally allow such transmissions in specified countries. In order to warn potential GPS users, the interference sources are being mapped.

Space very long baseline interferometry (VLBI) observations of the quasar 3C216 with the VLBI Space Observatory Programme (VSOP) reveal that the parsec scale structure of the source can be well described by compact jet models developed for interpreting the core region of radio-loud active galactic nuclei (AGN). The measured brightness temperature of T_(b) = 7.9*10^{11} K is comparable to the inverse Compton limit, from which we determine a lower limit of delta ~ 3.17 for the Doppler-boosting factor. The apparent transvers velocity of the superluminal component is beta_(app) = (3.0+-0.2) h^{-1} asuming a constant velocity, but deceleration of the jet material cannot be excluded from our data. A combination of the above values indicates that the viewing angle of the core-jet to the line-of-sight is less than 18.4 degrees, and the jet Lorentz-factor exceeds 3.16. The observed small size of the source is probably caused by both interaction with the interstellar medium, and a projection effect., 6 pages, 3 figures, accepted for publication by PASJ

This work deals with the theoretical investigation of the vibrational spectra of the As 2 S 5− x Se x (from x =0 to x =5 modes of glassy alloys) type compounds. Molecular geometries and vibrational spectra of all their conformers were calculated quantum chemically. Normal coordinate analysis was carried out for all these molecules. The results show the very characteristic positions of the central As–S and As–Se stretching frequencies. Besides, with increasing x all the normal modes become more and more characteristic, i.e. group frequencies. As expected, with increasing Se content the frequencies of the normal modes shifted to lower ones.

The fracture pattern around some gray bands on Europa has been investigated by edge and color enhancement techniques applied to some of the new Galileo images. The analysis supported the theoretical explanation on the origin of gray bands, namely that they took their origin from fracturing of the icy lithosphere, later the two margins moved away from each other leaving place for a newly formed strip of icy crust. The processed pictures reveal an older population of gray bands more clearly than the original images. Interestingly enough the newer gray band is cutting the old one at quite large angle of ∼70°. The measurement of ridge-width carried out inside the bands gave the same results of about 0.9 km independently of age.

The aim of our work is the investigation and modeling of arsenic sulfide glasses. In the frame of this program the structures and the vibrational frequencies of some fundamental arsenic sulfides clusters were calculated applying the ab initio Hartree–Fock method with LANL2DZ basis set. Two structures were supposed with two arsenic atoms: a non-branching one (As 2 S 3 ) and a double pyramid (As 2 S 5 ) others are an extended pyramid (As 4 S 6 ) and an extended double pyramid (As 6 S 9 ). The calculated structures were compared and analyzed. The calculated fundamental frequencies were compared with the experimental far infrared (400–30 cm −1 ) spectra of different types of arsenic sulfides. These were amorphous and crystalline arsenic sulfides and a deposited amorphous arsenic sulfide film. The calculated spectra are in good accordance with the experimental ones. It was concluded based on the far infrared spectra that possibly the two larger clusters take important role in the structure of arsenic sulfide glasses and films.

We present results of VLBA observations of SS433 at two epochs at 5, 8.4, and 15 GHz. The AU-scale region of the source is resolved and shows the familiar quasi-symmetric core-jet structures. But at another epoch, the maps show bright knots ejected a few days before the observation, while the core-complex disappeared. The bright jet components are completely depolarised with fractional polarization less than 0.5%. We also present the first VLBI image of SS433 at 22 GHz.

The Space VLBI Geodesy Demonstration Experiment (GEDEX) was designed to apply space VLBI delay and delay rate data for orbit reconstruction of the space VLBI satellite HALCA and to demonstrate, how to tie the Celestial Reference Frame to the Terrestrial Reference Frame directly using only space VLBI and tracking data. Software developments for these aims are being carried out by different groups in different countries. The effort is coordinated by the Satellite Geodetic Observatory in Hungary. The VSOP Survey Programme provides the observational basis for the experiment.

Previous suggestions of using space-VLBI for SETI are critically reviewed and some new suggestions presented. It is pointed out that the highly stable standard frequency uplink to the satellites can be considered as an active beacon of the terrestrial technical civilisation.

The Russian Academy of Sciences and Federal Space Agency, together with the participation of many international organizations, worked toward the launch of the RadioAstron orbiting space observatory with its onboard 10-m reflector radio telescope from the Baikonur cosmodrome on July 18, 2011. Together with some of the largest ground-based radio telescopes and a set of stations for tracking, collecting, and reducing the data obtained, this space radio telescope forms a multi-antenna ground-space radio interferometer with extremely long baselines, making it possible for the first time to study various objects in the Universe with angular resolutions a million times better than is possible with the human eye. The project is targeted at systematic studies of compact radio-emitting sources and their dynamics. Objects to be studied include supermassive black holes, accretion disks, and relativistic jets in active galactic nuclei, stellar-mass black holes, neutron stars and hypothetical quark stars, regions of formation of stars and planetary systems in our and other galaxies, interplanetary and interstellar plasma, and the gravitational field of the Earth. The results of ground-based and inflight tests of the space radio telescope carried out in both autonomous and ground-space interferometric regimes are reported. The derived characteristics are in agreement with the main requirements of the project. The astrophysical science program has begun., 54 pages, 11 figures; published by Astronomicheskij Zhurnal (in Russian) and Astronomy Reports (in English)

Background: The global obesity epidemic has paralleled a decrease in semen quality. Yet, the association between obesity and sperm parameters remains controversial. The purpose of this report was to update the evidence on the association between BMI and sperm count through a systematic review with meta-analysis. Methods: A systematic review of available literature (with no language restriction) was performed to investigate the impact of BMI on sperm count. Relevant studies published until June 2012 were identified from a Pubmed and EMBASE search. We also included unpublished data (n ¼ 717 men) obtained from the Infertility Center of Bondy, France. Abstracts of relevant articles were examined and studies that could be included in this review were retrieved. Authors of relevant studies for the meta-analysis were contacted by email and asked to provide standardized data. Results: A total of 21 studies were included in the meta-analysis, resulting in a sample of 13 077 men from the general population and attending fertility clinics. Data were stratified according to the total sperm count as normozoospermia, oligozoospermia and azoospermia. Standardized weighted mean differences in sperm concentration did not differ significantly across BMI categories. There was a J-shaped relationship between BMI categories and risk of oligozoospermia or azoospermia. Compared with men of normal weight, the odds ratio (95% confidence interval) for oligozoospermia or azoospermia was 1.15 (0.93–1.43) for underweight, 1.11 (1.01–1.21) for overweight, 1.28 (1.06– 1.55) for obese and 2.04 (1.59–2.62) for morbidly obese men. Conclusions: Overweight and obesity were associated with an increased prevalence of azoospermia or oligozoospermia. The main limitation of this report is that studied populations varied, with men recruited from both the general population and infertile couples. Whether weight normalization could improve sperm parameters should be evaluated further. Fil: Sermondade, N.. Hôpital Jean Verdier; Francia. Universite de Paris 13-nord; Francia Fil: Faure, C.. Hôpital Jean Verdier; Francia. Universite de Paris 13-nord; Francia Fil: Fezeu, L.. Universite de Paris 13-nord; Francia Fil: Shayeb, A. G.. University Hospital of Wales; Reino Unido Fil: Bonde, J. P.. Bispebjerg Hospital of Copenhagen University; Dinamarca Fil: Jensen, J. K.. University Department of Growth and Reproduction; Dinamarca Fil: Van Wely, M.. Academic Medical Centre; Países Bajos Fil: Cao, J.. Third Military Medical University; China Fil: Martini, Ana Carolina. Universidad Nacional de Córdoba. Facultad de Ciencias Médicas; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Cordoba. Instituto de Investigaciones en Ciencias de la Salud; Argentina Fil: Eskandar, M.. King Khalid University; Arabia Saudita Fil: Chavarro, J. E.. Harvard University. Harvard School Of Public Health; Estados Unidos. Harvard Medical School; Estados Unidos Fil: Koloszar, S.. University of Szeged; Hungría Fil: Twigt, J. M.. University Medical Center; Países Bajos Fil: Ramlau Hansen, C. H.. Aarhus University; Dinamarca Fil: Borges Jr, E.. Fertility-Assisted Fertilization Center; Brasil Fil: Lotti, F.. Universita Degli Studi Di Firenze; Italia Fil: Steegers Theunissen, R. P. M.. University Medical Center; Países Bajos Fil: Zorn, B.. University Medical Center Ljubljana; Eslovenia Fil: Polotsky, A. J.. University of Colorado Denver; Estados Unidos Fil: La Vignera, S.. University of Catania; Italia Fil: Eskenazi, B.. University Of California Berkeley; Estados Unidos Fil: Tremellen, K.. University of South Australia; Australia Fil: Magnusdottir, E. V.. University of Iceland; Islandia Fil: Fejes, I.. University of Szeged; Hungría Fil: Hercberg, S.. Universite de Paris 13-nord; Francia. Hôpital Avicenne; Francia Fil: Lévy, R.. Hôpital Jean Verdier; Francia. Universite de Paris 13-nord; Francia Fil: Czernichow, S.. University of Versailles Saint Quentin en Yvelines; Francia. Centre for Research in Epidemiology and Population Health; Francia

Space VLBI is a new observing technique which will be available in the second half of this decade by radio telescopes as interferometer elements in orbit. Besides the main astronomical interests, this new development has some very interesting potential applications in satellite dynamics, geodesy and geodynamical research which qualify space VLBI a potential new technique in space geodesy. A geodesy demostration experiment (GEDEX) is being proposed for the Japanese space VLBI satellite-VSOP, with the main objectives of reference frame interconnections and orbit accuracy improvement of the space radio telescope. The paper gives a review of the special characteristics of space VLBI and a general background of the GEDEX proposal.

The new VLBI observing technique-space-VLBI-has several aspects which will have implications in the field of geodynamics and satellite dynamics. We point out the particular characteristics of space-VLBI which distinguish it from the ground based VLBI, and from other space geodetic techniques. Three areas are reviewed: the kinematic, the dynamic and the measurements characteristics of space-VLBI. For satellite dynamics the application of space-VLBI delay and delay rate as satellite tracking data is particularly interesting. It has been demonstrated by simulations that this new type of tracking data can significantly contribute to the accuracy of orbit determination. We give a summary of the mathematical model concerning orbit and geodynamical parameter estimations. It implies applications for tying reference frames directly and to give orientation for geodynamic satellites in an extraterrestrial inertial frame. The accuracy requirements of orbit determination for these applications are very stringent - submeter level is needed while the satellites have unfavourable physical shapes in this respect. This poses a challenge for precise modelling and tracking. Simulation studies carried out by different groups are reviewed. Preliminary results indicate, that the submeter level may be achieved if special tracking techniques are applied.

The usefulness of space-VLBI for astrometric and geodynamic applications depends strongly on the orbit determination accuracy of the satellites involved. The requirements are very strict. In this paper, the results are presented of some preliminary investigations on the achievable orbit accuracy of the Soviet Radioastron and the ESA QUASAT space-VLBI satellites. For this purpose, simulations have been performed for a total of 23 orbital arcs, in which satellite observations from Precise Range and Range-rate Equipment (PRARE) were considered, as well as VLBI-type tracking of the satellite signals. The assumed tracking network consisted of 2 to 3 VLBI and 3 to 18 PRARE stations. The computations were carried out at Delft University of Technology using a computer program for covariance analysis of orbit determination problems.

A Cone Penetration Test (CPT) survey with a high spatial resolution was performed in order to investigate the stratigraphy as well as the spatial variability of various soil properties of the Krauthausen test site. Analyses of the CPT measurements showed the subsurface to be dominated by a planar layered structure. Variogram analysis of the various CPT parameters disclosed that within each layer the soil properties have an anisotropic spatial correlation structure. A correlation analysis of the measured CPT data and co-located grain size distributions from soil samples was performed. Since the correlation coefficients were greater equal to 0.7, a reliable empirical relationship between the data sets could be developed. Based on this empirical relationship grain size distributions were estimated at CPT locations. The statistical processing of estimated and measured grain size distributions with respect to their spatial correlation structure disclosed good agreement between the data sets. The estimated grain size distributions from CPT data were used to estimate the hydraulic conductivity in the aquifer. The results provide detailed information of the spatial heterogeneity of the hydraulic conductivity at Krauthausen test site. The validation of these results, using a prior investigation of hydraulic conductivity statistics, suggests the CPT a fast and inexpensive tool for the estimation of three dimensional hydraulic conductivity fields with sufficient accuracy.

In former papers (Fejes, Josa, 1990; Draskovits, Fejes, Magyar, Stickel, 1999 and 2000), measurement and geological-petrophysical interpretation of mechanical and nuclear parameters obtained with the help of the own-developped CPT equipment were introduced. In the present paper the possibility for measuring a following parameter, the resistivity will be shown.

The unique radio astronomical technique of Space Very Long Baseline Interferometry (SVLBI) is an extension of the ground-based VLBI into the space. It has some important potential applications in geodesy and geodynamics, including the definition, practical realization, and interconnection of different reference frames, determining the geocentric positions of VLBI stations, estimation of the gravity field of the Earth, and satellite orbit determination using the delay and delay rate observables. With the launching of the first SVLBI satellite of the VLBI Space Observatory Programme (VSOP) of Japan, in February 1997, this technique has become a reality. An international team of scientists, working under the auspices of the FOMI Satellite Geodetic Observatory, Hungary, has designed the GEDEX, for the purpose of exploring the feasibility of the geodetic applications of SVLBI.

From parameters acquisited during static soundings or cone penetration tests (CPT) combined with nuclear measurements, a very detailed geological data set (thickness and geological identification of the penetrated formations, their moisture content, filtration coefficient, etc.) can be obtained [1]. In the present paper we show that over the geological information other important parameters used in the engineering practice can be derived from the same measured values. Earlier these parameters could be obtained in laboratory examinations only, but - as in case of most laboratory tests - the physical status of the analyzed sample is not the same as in its original circumstances. Thus any in-situ determination or even realistic estimation method is of great practical importance.

In progressive soil mechanical examination and reconnaissance geological surveys the Cone Penetrating Test (CPT) is widely applied. Special features of the geological structure of Hungary necessitated the further development of the method and the enlargement of measured physical quantities. Thus the environmental examinations gained a new too) which possesses promising perspectives due to objectiveness and in-situ applicability of the method. In the beginning, the method consisted of measurement of mechanical parameters: the cone pressure necessary for penetrating the measuring probe ending in a standardized cone into the soil, and the so-called total pressure (inside the hydraulic system). Later nuclear measuring procedures have been adopted from well logging: natural gamma, gamma-gamma and neutron-neutron intensities are measured. These nuclear measurements can be carried out even in the drilling rod. The measured parameters provide information on independent rock mechanical characteristics: cone pressure on the breaking strength on the layers penetrated, natural gamma intensity on the clay content and the neutron-neutron on the water content (more precisely on the hydrogen content). Recently we are able to measure the resistivity of the surrounding of the probe pressed down into the soil.

The aim of the GEDEX, which is being designed by an international team of scientists, is to explore the feasibility of Geodetic & Geodynamic applications of Space VLBI. In this paper, the outline of this experiment has been presented. A brief description of the Space VLBI technique has been provided, followed by a summary of the significant theoretical developments. Salient features of the VSOP mission. and an overview of the various aspects of GEDEX have been presented. The state of the art of software for Geodetic SVLBI has been outlined, and the different steps in software development for the GEDEX have been described in detail. Conclusions drawn from the work done so far, and recommendations for future work have been presented.

The quasar 3C216 has the distinction of being classified as a blazar as well as a compact steep-spectrum radio source (Akujor et al, 1993). It has a grossly mis-aligned large-scale radio structure. Previous VLBI images include those of the core region (Barthel et al 1988; Venturi et al 1993) with 1 mas resolution, and the sub-kpc scale core-jet with resolution ca. 25 mas (Fejes et al, 1992; Akujor et al, 1993). In order to investigate the connection between these structures seen on different scales, we have made a 1.6 GHz observation of the core-jet region with a “World Array” VLBI network. This consisted of 20 antennas, at Effelsberg (Germany), Jodrell “Lovell” (UK), Westerbork (Netherlands), Medicina and Noto (Italy), Onsala-26m (Sweden), Torun-15m (Poland), Simeiz (Ukraine), Bear Lakes (Russia), Seshan (China), Hartebeesthoek (S. Africa), Green Bank-43m, VLA and the VLBA antennas at HN, NL, PT, KP, LA, BR, OV (USA). The observations were made on 18 November, 1992, using the Mk2 recording system, and these were amongst the last to be correlated using the JPL-Caltech Block2 processor. The NRAO AIPS package was used for the data analysis.

The radio-jet X-ray binary SS433 was observed at five epochs in 1998 by the very long baseline interferometry (VLBI) technique at five frequencies ranging from 1.6 to 22 GHz. The innermost region of the source on milliarcsecond scales (1 mas = 5 AU) is resolved into an eastern and a western core-jet component, well separated by the Central Radio Gap (25-30 AU projected size), where the binary stellar system is located. We suggest that the radio gap is caused by local synchrotron self-absorption and external free-free absorption in an ionized medium, which has a disk-like geometry. On 100 AU scales we observe the Equatorial Emission Region, oriented roughly perpendicularly to the jets, with variable morphology at different epochs. Both of these phenomena could be interpreted with a mass outflow from the system, concentrated in the orbital plane of the binary.

In the next decade — the 90-es — dedicated radio telescopes will be launched into Earth orbit and will be integrated in the ground based Very Long Baseline Interferometry (VLBI) networks. Space-VLBI an emerging new observational technique will be with us.

Precise orbit determination (OD) has two basic ingradients: - precise orbit model and - precise tracking data.

A new version of the Space VLBI Assistance Software (SPAS) developed at the FÖMI Satellite Geodetic Observatory (Penc, Hungary) is described. SPAS version 2.0 will be a useful software tool for proposal preparation in response to the second Announcement of Opportunity of the VSOP satellite.

The quasar 3C216 has the distinction of being classified as a blazar as well as a compact steep-spectrum radio source (Akujor et al, 1993). It has a grossly mis-aligned large-scale radio structure. Previous VLBI images include those of the core region (Barthel et al 1988; Venturi et al 1993) with 1 mas resolution, and the sub-kpc scale core-jet with resolution ca. 25 mas (Fejes et al, 1992; Akujor et al, 1993). In order to investigate the connection between these structures seen on different scales, we have made a 1.6 GHz observation of the core-jet region with a “World Array” VLBI network. This consisted of 20 antennas, at Effelsberg (Germany), Jodrell “Lovell” (UK), Westerbork (Netherlands), Medicina and Noto (Italy), Onsala-26m (Sweden), Torun-15m (Poland), Simeiz (Ukraine), Bear Lakes (Russia), Seshan (China), Hartebeesthoek (S. Africa), Green Bank-43m, VLA and the VLBA antennas at HN, NL, PT, KP, LA, BR, OV (USA). The observations were made on 18 November, 1992, using the Mk2 recording system, and these were amongst the last to be correlated using the JPL-Caltech Block2 processor. The NRAO AIPS package was used for the data analysis.

A comprehensive series of VLBI (very-long-baseline interferometry) observations of SS433, carried out over an 11-day period on the European VLSI Network at 5 GHz, reveals the motion and evolution of a series of faint 'blobs' ejected from the system. These blobs are observed to brighten at a substantial distance from the binary star.

A unique characteristic of space-VLBI for geodynamic studies is pointed out: space-VLBI provides a direct connection between the Conventional Inertial Reference System of extragalactic radio sources and geocentric reference systems of extragalactic radio sources and geocentric reference systems defined by dynamical methods respectively. New satellite projects (Quasat, Radioastron) are in preparation requiring precise orbits; different satellite tracking methods are discussed for this purpose.

A fast and simple method is proposed for Doppler receiver pair quality evaluation. By evaluating collocated raw Doppler data the noise characteristics of the receivers can be directly obtained. Test evaluations of JMR receivers are presented.

Earlier investigations have shown that there is a preponderance of negative velocities in the hydrogen gas at high latitudes, and that in certain areas very little low-velocity gas occurs. In the region 100°

A campaign of VLBI observations of SS433 using the European network was begun in January 1980 and since October 1980 has continued at intervals of about two months except for the last two observations which were 6 days apart, see Table 1. The results of the first two epochs have been published in Nature (ref. 1), and those of the following six epochs are being prepared for publication.

A campaign of VLBI observations of SS433 using the European network vas begun in January 1980 and since October 1980 has continued at intervals of about two months except for the last two observations which were 6 days apart, see Table 1. The results of the first two epochs have been published in Nature (ref. 1), and those of the following six epochs are being prepared for publication.

SS433 has been observed extensively in virtually all wavelength regimes. In the X-ray (Seward et al. 1979) and the radio (Hjellming and Johnston, 1981a, b, 1982; Spencer 1979, Schilizzi et al. 1981, 1982; Niell et al. 1981, 1982) there is clear evidence of jets emanating from the central star system in the direction of the well-known extensions in the surrounding shell of emission, W50. Our VLBI observations of SS433 in 1980 and 1981 were made at wavelengths ranging from 6 to 21 cm (beamsizes of 10 to 100 milli-arcsec or ∿ 1015 to 1016 cm at the distance of W50) and had sufficient resolution to distinguish individual blobs of emission in the jets. An example is shown in Fig. 1

We present results of 1.6 GHz HALCA observation of the high redshift quasar 3C446 in which the Australia Compact Array, Hartebeesthoek, Shanghai and Usuda ground VLBI stations have participated. The core of 3C446 is resolved, there is an extension to PA=−123°. We give a lower limit of 0.97 for the spectral index of the innermost region (S∼ v α ). A high resolution space VLBI image of the radio core and an interpretation of the observed structure is presented.