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Asteroseismic scaling relations can provide high-precision measurements of mass and radius for red giant (RG) stars displaying solar-like oscillations. Their accuracy can be validated and potentially improved using independent and accurate observations of mass, radius, effective temperature and metallicity. We seek to achieve this using long period SB2 eclipsing binaries hosting oscillating RGs. We explore KIC 8430105, for which a previous study found significant asteroseismic overestimation of mass and radius when compared with eclipsing binary measurements. We measured dynamical masses and radii for both components to be significantly lower than previously established, increasing the discrepancy between asteroseismic and dynamical measurements. Our dynamical measurements of the RG component were compared to corresponding measurements of mass and radius using asteroseismic scaling relations. Uncorrected scaling relations overestimated the mass of the RG by 26%, the radius by 11%, and the average density by 7%, in agreement with studies for other systems. However, using a theoretical correction to $\Delta \nu$, we managed to obtain an asteroseismic average density that is $1\sigma$ consistent with our dynamical result. We obtained several measurements of $\nu_{max}$ that are not fully consistent. With $\nu_{max} = 76.78 \pm 0.81\mu $Hz, the $\Delta \nu$ correction provided $2 \sigma$ consistent mass and radius for the giant. The age of the system was estimated to be $3.7 \pm 0.4$ Gyr., Comment: 18 pages, 5 figures, to be published in Monthly Notices of the Royal Astronomical Society

Eclipsing binary stars with an oscillating giant component allow accurate stellar parameters to be derived and asteroseismic methods to be tested and calibrated. To this aim, suitable systems need to be firstly identified and secondly measured precisely and accurately. KIC 4054905 is one such system, which has been identified, but with measurements of a relatively low precision and with some confusion regarding its parameters and evolutionary state. Our aim is to provide a detailed and precise characterisation of the system and to test asteroseismic scaling relations. Dynamical and asteroseismic parameters of KIC4054905 were determined from Kepler photometry and multi-epoch high-resolution spectra from FIES at the Nordic Optical Telescope. KIC 4054905 was found to belong to the thick disk and consist of two lower red giant branch (RGB) components with nearly identical masses of 0.95$M_{\odot}$ and an age of $9.9\pm0.6$ Gyr. The most evolved star displays solar-like oscillations, which suggest that the star belongs to the RGB, supported also by the radius, which is significantly smaller than the red clump phase for this mass and metallicity. Masses and radii from corrected asteroseismic scaling relations can be brought into full agreement with the dynamical values if the RGB phase is assumed, but a best scaling method could not be identified. We measured dynamical masses and radii with a precision better than 1.0%. We firmly establish the evolutionary nature of the system to be that of two early RGB stars with an age close to 10 Gyr, unlike previous findings. The metallicity and Galactic velocity suggest that the system belongs to the thick disk of the Milky Way. We investigate the agreement between dynamical and asteroseismic parameters for KIC 4054905. Consistent solutions exist, but the need to analyse more systems continues in order to establish the accuracy of asteroseismic methods., Accepted for publication in Astronomy & Astrophysics, 11 pages, 3 figures

In fulfilling the aims of the planetary and asteroseismic research missions, such as that of the NASA Transiting Exoplanet Survey Satellite (TESS) space telescope, accurate stellar atmospheric parameters and a detailed chemical composition are required as input. We have observed high-resolution spectra for all 848 bright (V, Comment: 17 pages, 8 figures. arXiv admin note: text overlap with arXiv:2005.07526

Accurate atmospheric parameters and chemical composition of stars play a vital role in characterizing physical parameters of exoplanetary systems and understanding of their formation. A full asteroseismic characterization of a star is also possible if its main atmospheric parameters are known. The NASA Transiting Exoplanet Survey Satellite (TESS) space telescope will play a very important role in searching of exoplanets around bright stars and stellar asteroseismic variability research. We have observed all 302 bright (V < 8 mag) and cooler than F5 spectral class stars in the northern TESS continuous viewing zone with a 1.65 m telescope at the Moletai Astronomical Observatory of Vilnius University and the high-resolution Vilnius University Echelle Spectrograph. We uniformly determined the main atmospheric parameters, ages, orbital parameters, velocity components, and precise abundances of 24 chemical species ( C(C2), N(CN), [O I], Na I, Mg I, Al I, Si I, Si II, Ca I, Ca II, Sc I, Sc II, Ti I, Ti II, V I, Cr I, Cr II, Mn I, Fe I, Fe II, Co I, Ni I, Cu I, and Zn I) for 277 slowly rotating single stars in the field. About 83 % of the sample stars exhibit the Mg/Si ratios greater than 1.0 and may potentially harbor rocky planets in their systems., 15 pages, 12 figures, published in ApJS, 2020 May 12

A spectroscopic analysis of stellar spectra can be carried out using different approaches; different methods, line lists, atomic parameters, solar abundances etc. The resulting atmospheric parameters from these choices can vary beyond quoted uncertainties in the literature. Here we characterize these differences by systematically comparing some of the commonly adopted ingredients; line lists, equivalent width measurements and atomic parameters. High resolution and high signal-to-noise spectroscopic data of one helium-core-burning red giant star in each of the three open clusters, NGC6819, M67 and NGC188 have been obtained with the FIES spectrograph at the Nordic Optical Telescope. The M67 target has been used to benchmark the analysis, as it is a well studied cluster with asteroseismic data from the K2 mission. For the other two clusters we have obtained higher quality data than previously analyzed, which allows us to establish their chemical composition more securely. Using a line by line analysis, we tested several different combinations of line lists and programs to measure equivalent widths of absorption lines to characterize systematic differences within the same spectroscopic method. The obtained parameters for the benchmark star in M67 vary up to ~170 K in T_eff, ~0.4 dex in log g and ~0.25 dex in [Fe/H] between the tested setups. Using the combination of equivalent width measurement program and line list that best reproduce the inferred log g from asteroseismology, we determined the atmospheric parameters for the three stars and securely established the chemical composition of NGC6819 to be ~solar, [Fe/H]=-0.02+-0.01 dex. We have highlighted the significantly different results obtained with different combinations of line lists, programs and atomic parameters, which emphasize the importance of benchmark stars studied with several different methods to anchor spectroscopic analyses., Accepted for publication in Astronomy and Astrophysics

We determine the properties of the binary star V106 in the old open cluster NGC6791. We identify the system to be a blue straggler cluster member by using a combination of ground-based and Kepler photometry and multi-epoch spectroscopy. The properties of the primary component are found to be $M_{\rm p}\sim1.67 \rm M_{\odot}$, more massive than the cluster turn-off, with $R_{\rm p}\sim1.91 \rm R_{\odot}$ and $T_{\rm eff}=7110\pm100$ K. The secondary component is highly oversized and overluminous for its low mass with $M_{\rm s}\sim0.182 \rm M_{\odot}$, $R_{\rm s}\sim0.864 \rm R_{\odot}$ and $T_{\rm eff}=6875\pm200$ K. We identify this secondary star as a bloated (proto) extremely low-mass helium white dwarf. These properties of V106 suggest that it represents a typical Algol-paradox system and that it evolved through a mass-transfer phase which provides insight into its past evolution. We present a detailed binary stellar evolution model for the formation of V106 using the MESA code and find that the mass-transfer phase only ceased about 40 Myr ago. Due to the short orbital period (P=1.4463 d) another mass-transfer phase is unavoidable once the current primary star evolves towards the red giant phase. We argue that V106 will evolve through a common-envelope phase within the next 100 Myr and merge to become a single over-massive giant. The high mass will make it appear young for its true age, which is revealed by the cluster properties. Therefore, V106 is potentially a prototype progenitor of old field giants masquerading as young., Comment: 12 pages, 7 figures, accepted for publication in MNRAS

We aim to establish and improve the accuracy level of asteroseismic estimates of mass, radius, and age of giant stars. This can be achieved by measuring independent, accurate, and precise masses, radii, effective temperatures and metallicities of long period eclipsing binary stars with a red giant component that displays solar-like oscillations. We measured precise properties of the three eclipsing binary systems KIC 7037405, KIC 9540226, and KIC 9970396 and estimated their ages be $5.3\pm0.5$, $3.1\pm0.6$, and $4.8\pm0.5$ Gyr. The measurements of the giant stars were compared to corresponding measurements of mass, radius, and age using asteroseismic scaling relations and grid modeling. We found that asteroseismic scaling relations without corrections to $\Delta\nu$ systematically overestimate the masses of the three red giants by 11.7%, 13.7%, and 18.9%, respectively. However, by applying theoretical correction factors $f_{\Delta\nu}$ according to Rodrigues et al. (2017), we reached general agreement between dynamical and asteroseismic mass estimates, and no indications of systematic differences at the precision level of the asteroseismic measurements. The larger sample investigated by Gaulme et al. (2016) showed a much more complicated situation, where some stars show agreement between the dynamical and corrected asteroseismic measures while others suggest significant overestimates of the asteroseismic measures. We found no simple explanation for this, but indications of several potential problems, some theoretical, others observational. Therefore, an extension of the present precision study to a larger sample of eclipsing systems is crucial for establishing and improving the accuracy of asteroseismology of giant stars., Comment: Accepted for publication in MNRAS, 17 pages

Previously [Y/Mg] has been proven to be an age indicator for solar twins. Here, we investigate if this relation also holds for helium-core-burning stars of solar metallicity. High resolution and high signal-to-noise ratio (S/N) spectroscopic data of stars in the helium-core-burning phase have been obtained with the FIES spectrograph on the NOT 2.56m telescope and the HIRES spectrograph on the Keck I 10 m telescope. They have been analyzed to determine the chemical abundances of four open clusters with close to solar metallicity; NGC 6811, NGC 6819, M67 and NGC 188. The abundances are derived from equivalent widths of spectral lines using ATLAS9 model atmospheres with parameters determined from the excitation and ionization balance of Fe lines. Results from asteroseismology and binary studies were used as priors on the atmospheric parameters, where especially the $\log g$ is determined to much higher precision than what is possible with spectroscopy. It is confirmed that the four open clusters are close to solar metallicity and they follow the [Y/Mg] vs. age trend previously found for solar twins. The [Y/Mg] vs. age clock also works for giant stars in the helium-core burning phase, which vastly increases the possibilities to estimate the age of stars not only in the solar neighborhood, but in large parts of the Galaxy, due to the brighter nature of evolved stars compared to dwarfs., Comment: 5 pages, 3 figures, accepted for publication as a Letter to A&A

We present the results of a photometric search for variable stars in the core of the Galactic globular cluster M4. The input data are a large and unprecedented set of deep Hubble Space Telescope WFC3 images (large program GO-12911; 120 orbits allocated), primarily aimed at probing binaries with massive companions by detecting their astrometric wobbles. Though these data were not optimised to carry out a time-resolved photometric survey, their exquisite precision, spatial resolution and dynamic range enabled us to firmly detect 38 variable stars, of which 20 were previously unpublished. They include 19 cluster-member eclipsing binaries (confirming the large binary fraction of M4), RR Lyrae, and objects with known X-ray counterparts. We improved and revised the parameters of some among published variables., Comment: 11 pages, 5 figures, 2 tables. Accepted for publication in MNRAS

We present an overview of the ongoing Hubble Space Telescope large program GO-12911. The program is focused on the core of M4, the nearest Galactic globular cluster, and the observations are designed to constrain the number of binaries with massive companions (black holes, neutron stars, or white dwarfs) by measuring the ``wobble'' of the luminous (main-sequence) companion around the center of mass of the pair, with an astrometric precision of ~50 micro-arcseconds. The high spatial resolution and stable medium-band PSFs of WFC3/UVIS will make these measurements possible. In this work we describe: (i) the motivation behind this study, (ii) our observing strategy, (iii) the many other investigations enabled by this unique data set, and which of those our team is conducting, and (iv) a preliminary reduction of the first-epoch data-set collected on October 10, 2012.

Mass loss of red giant branch (RGB) stars is still poorly determined, despite its crucial role in the chemical enrichment of galaxies. Thanks to the recent detection of solar-like oscillations in G-K giants in open clusters with Kepler, we can now directly determine stellar masses for a statistically significant sample of stars in the old open clusters NGC6791 and NGC6819. The aim of this work is to constrain the integrated RGB mass loss by comparing the average mass of stars in the red clump (RC) with that of stars in the low-luminosity portion of the RGB (i.e. stars with L

We report the first asteroseismic results obtained with the Hertzsprung SONG Telescope from an extensive high-precision radial-velocity observing campaign of the subgiant muHerculis. The data set was collected during 215 nights in 2014 and 2015. We detected a total of 49 oscillation modes with l values from 0 to 3, including some l = 1 mixed modes. Based on the rotational splitting observed in l = 1 modes, we determine a rotational period of 52 days and a stellar inclination angle of 63 degrees. The parameters obtained through modeling of the observed oscillation frequencies agree very well with independent observations and imply a stellar mass between 1.11 and 1.15M_sun and an age of 7.8+/-0.4 Gyr. Furthermore, the high-quality data allowed us to determine the acoustic depths of the He II ionization layer and the base of the convection zone., Comment: 17 pages, 15 figures. Accepted for publication in ApJ

The M4 Core Project with HST is designed to exploit the Hubble Space Telescope to investigate the central regions of M4, the Globular Cluster closest to the Sun. In this paper we combine optical and near-infrared photometry to study multiple stellar populations in M4. We detected two sequences of M-dwarfs containing ~38% (MS_I) and ~62% (MS_II) of MS stars below the main-sequence (MS) knee. We compare our observations with those of NGC2808, which is the only other GCs where multiple MSs of very low-mass stars have been studied to date. We calculate synthetic spectra for M-dwarfs, assuming the chemical composition mixture inferred from spectroscopic studies of stellar populations along the red giant branch, and different Helium abundances, and we compare predicted and observed colors. Observations are consistent with two populations, one with primordial abundance and another with enhanced nitrogen and depleted oxygen., Comment: 8 pages, 6 figure, accepted for publication in MNRAS

The NASA space telescope Kepler has provided unprecedented time-series observations which have revolutionised the field of asteroseismology, i.e. the use of stellar oscillations to probe the interior of stars. The Kepler-data include observations of stars in open clusters, which are particularly interesting for asteroseismology. One of the clusters observed with Kepler is NGC 6811, which is the target of the present paper. However, apart from high-precision time-series observations, sounding the interiors of stars in open clusters by means of asteroseismology also requires accurate and precise atmospheric parameters as well as cluster membership indicators for the individual stars. We use medium-resolution (R~25,000) spectroscopic observations, and three independent analysis methods, to derive effective temperatures, surface gravities, metallicities, projected rotational velocities and radial velocities, for 15 stars in the field of the open cluster NGC 6811. We discover two double-lined and three single-lined spectroscopic binaries. Eight stars are classified as either certain or very probable cluster members, and three stars are classified as non-members. For four stars, cluster membership could not been assessed. Five of the observed stars are G-type giants which are located in the colour-magnitude diagram in the region of the red clump of the cluster. Two of these stars are surely identified as red clump stars for the first time. For those five stars, we provide chemical abundances of 31 elements. The mean radial-velocity of NGC 6811 is found to be +6.68$\pm$0.08 km s$^{-1}$ and the mean metallicity and overall abundance pattern are shown to be very close to solar with an exception of Ba which we find to be overabundant., Comment: 18 pages, 11 tables, 7 figures, accepted for MNRAS

Context. Detached eclipsing binaries (dEBs) are ideal targets for accurately measuring the masses and radii of their component stars. If at least one of the stars has evolved off the main sequence (MS), the masses and radii give a strict constraint on the age of the stars. Several dEBs containing a bright K giant and a fainter MS star have been discovered by the Kepler satellite. The mass and radius of a red giant (RG) star can also be derived from its asteroseismic signal. The parameters determined in this way depend on stellar models and may contain systematic errors. It is important to validate the asteroseismically determined mass and radius with independent methods. This can be done when stars are members of stellar clusters or members of dEBs.Aims. This paper presents an analysis of the dEB system KIC 8410637, which consists of an RG and an MS star. The aim is to derive accurate masses and radii for both components and provide the foundation for a strong test of the asteroseismic method and the accuracy of the deduced mass, radius, and age.Methods. We analysed high-resolution, high-signal-to-noise spectra from three different spectrographs. We also calculated a fit to the Kepler light curve and used ground-based photometry to determine the flux ratios between the component stars in the BVRI passbands.Results. We measured the masses and radii of the stars in the dEB, and the classical parameters Teff, log g, and [Fe/H] from the spectra and ground-based photometry. The RG component of KIC 8410637 is most likely in the core helium-burning red clump phase of evolution and has an age and composition that are very similar to the stars in the open cluster NGC 6819. The mass of the RG in KIC 8410637 should therefore be similar to the mass of RGs in NGC 6819, thus lending support to the latest version of the asteroseismic scaling relations. This is the first direct measurement of both mass and radius for an RG to be compared with values for RGs from asteroseismic scaling relations thereby providing an accurate comparison. We find excellent agreement between log g values derived from the binary analysis and asteroseismic scaling relations.Conclusions. We have determined the masses and radii of the two stars in the binary accurately. A detailed asteroseismic analysis will be presented in a forthcoming paper, allowing an informative comparison between the parameters determined for the dEB and from asteroseismology.

Studying star clusters offers significant advances in stellar astrophysics due to the combined power of having many stars with essentially the same distance, age, and initial composition. This makes clusters excellent test benches for verification of stellar evolution theory. To fully exploit this potential, it is vital that the star sample is uncontaminated by stars that are not members of the cluster. Techniques for determining cluster membership therefore play a key role in the investigation of clusters. We present results on three clusters in the Kepler field of view based on a newly established technique that uses asteroseismology to identify fore- or background stars in the field, which demonstrates advantages over classical methods such as kinematic and photometry measurements. Four previously identified seismic non-members in NGC6819 are confirmed in this study, and three additional non-members are found -- two in NGC6819 and one in NGC6791. We further highlight which stars are, or might be, affected by blending, which needs to be taken into account when analysing these Kepler data., 12 pages, 9 figures, 5 tables, accepted by ApJ

We have analyzed data from a multi-site campaign to observe oscillations in the F5 star Procyon. The data consist of high-precision velocities that we obtained over more than three weeks with eleven telescopes. A new method for adjusting the data weights allows us to suppress the sidelobes in the power spectrum. Stacking the power spectrum in a so-called echelle diagram reveals two clear ridges that we identify with even and odd values of the angular degree (l=0 and 2, and l=1 and 3, respectively). We interpret a strong, narrow peak at 446 muHz that lies close to the l=1 ridge as a mode with mixed character. We show that the frequencies of the ridge centroids and their separations are useful diagnostics for asteroseismology. In particular, variations in the large separation appear to indicate a glitch in the sound-speed profile at an acoustic depth of about 1000 s. We list frequencies for 55 modes extracted from the data spanning 20 radial orders, a range comparable to the best solar data, which will provide valuable constraints for theoretical models. A preliminary comparison with published models shows that the offset between observed and calculated frequencies for the radial modes is very different for Procyon than for the Sun and other cool stars. We find the mean lifetime of the modes in Procyon to be 1.29 +0.55/-0.49 days, which is significantly shorter than the 2-4 days seen in the Sun., Comment: accepted for publication in ApJ

Procyon A is a bright F5IV star in a binary system. Although the distance, mass and angular diameter of this star are all known with high precision, the exact evolutionary state is still unclear. Evolutionary tracks with different ages and different mass fractions of hydrogen in the core pass, within the errors, through the observed position of Procyon A in the Hertzsprung-Russell diagram. For more than 15 years several different groups have studied the solar-like oscillations in Procyon A to determine its evolutionary state. Although several studies independently detected power excess in the periodogram, there is no agreement on the actual oscillation frequencies yet. This is probably due to either insufficient high-quality data (i.e., aliasing) or due to intrinsic properties of the star (i.e., short mode lifetimes). Now a spectroscopic multi-site campaign using 10 telescopes world-wide (minimizing aliasing effects) with a total time span of nearly 4 weeks (increase the frequency resolution) is performed to identify frequencies in this star and finally determine its properties and evolutionary state., 7 pages, 4 figures to be published in the proceedings of HELAS II International Conference: Helioseismology, Asteroseismology and MHD Connections published in the Journal of Physics: Conference Series. High resolution colour figures can be provided on request

Introduction: In our region Advanced Emergency Medical Technicians (AEMTs) respond to acutely ill or injured patients in rural areas. The AEMTs have been authorized to administer fentanyl intravenously in doses up to 2 μg/kg to selected groups of patients in pain. Higher doses can be allowed by a physician after a teleconference. We examined the effect of intravenous (IV) fentanyl treatment, expressed as pain reduction on a 10-point Numeric Rating Scale (NRS). Moreover we examined the occurrence of negative coincident events to assess whether it was safe to let non-medical staff administer potent opioids intravenously. Methods: Retrospectively we collected the case sheets for all patients treated with IV fentanyl by the AEMTs in 2005 and 2006. We excluded all patients where a physician had been directly involved in the prehospital treatment. We recorded the IV fentanyl dose, NRS-score before and after fentanyl administration, the use of naloxone, as well as all recorded incidents of nausea or vomiting, hypoxia, hypotension, bradycardia and bradypnea following treatment with IV fentanyl. Results: A total of 564 patients were treated with IV fentanyl by the AEMTs. Thirtyseven patients were excluded. The remaining 527 patients (mean age: 55 years) were treated solely by the AEMTs and received a median dose of 100 μg IV fentanyl (quartiles: 70 μg; 120 μg), which lead to a decrease in median NRS-score on 5 (quartiles: 4; 6). Negative coincident events were recorded in 25 (4.7 %) patients. Two of those became unconscious immediately following fentanyl administration. One was treated successfully with IV naloxone and regained consciousness promptly. The other regained consciousness before naloxone treatment was commenced. In the remaining 23 patients negative coincident events were considered minor, and were not treated with naloxone. Conclusions: Our results suggest that non-medical personnel safely can administer IV fentanyl to selected groups of patients with a satisfactory result in terms of a considerable reduction in pain score and an acceptable rate of negative coincident events.

Semen for use in artificial insemination must be of good quality. To satisfy this demand we have to be able to predict the quality of semen from individual donors. Statistical analyses of data on 3,418 ejaculates from 87 donors demonstrated that each donor's ejaculates could be characterized by a lognormal distribution of the sperm concentration, the concentration of motile spermatozoa before freezing and the concentration of motile spermatozoa after thawing. Furthermore, the ratio of the concentration of motile spermatozoa before freezing to the total sperm concentration and the fraction of motile spermatozoa surviving the freezing procedure were found to be constant for individual donors. Based on these observations a statistical quality control scheme for the selection of donors and for the continuous control of semen quality is presented.

Summary. The clinical significance of placental perforation and bloodstained amniotic fluid was studied in a group of 7238 Danish women undergoing mid-trimester amniocentesis for prenatal diagnosis under ultrasound guidance. The risk of spontaneous abortion was significantly increased both in pregnancies where the placenta was perforated and in those with blood-stained amniotic fluid. The risk estimate nearly doubled after placental perforation and more than doubled with a bloody tap. It is concluded that for women at relatively low risk of a fetal genetic abnormality, the indication of the amniocentesis should be reconsidered if a placental perforation is unavoidable.

The results obtained by insemination with 3,418 frozen donor ejaculates with known semen characteristics were analyzed. The concentrations of motile spermatozoa before and after thawing were significantly higher in samples from donors producing pregnancies compared to samples from donors not causing pregnancies. In ejaculates known specifically to have caused a pregnancy even higher concentrations were found. It was assumed that the concentration of motile spermatozoa after thawing was the most important parameter, and by dividing the material into fractions it could be demonstrated that a spermatozoa concentration of more than 20 million/ml is essential for reasonable results.

A central semen bank in Denmark supplied deep-frozen semen. Selection of donors, freezing technique, and practical details about transport of specimens are described. In one of the gynaecological departments supplied with frozen semen, 22 out of 30 patients who had artificial insemination became pregnant. The advantages and disadvantages of using frozen semen are discussed.The experience with the establishment of a central semen bank to serve gynecological departments in all of Denmark is described. In that the conception rate seems to be lower with frozen than with fresh semen, only ejaculates with a volume above 2 ml were accepted. Ejaculates were accepted in which 50% of the sperms remained mobile after trial freezing. Each ejaculate was frozen in portions of 0.5 ml and on the next day 1 of the portions was thawed out and examined for sperm motility. Of 200 donors about 50 had an initially acceptable semen volume and sperm count, but in only 1/2 of these was sperm motility satisfactory after a test freezing of semen. The semen was frozen immediately after liquefaction and always within 60 minutes of ejaculation. The method used was the 1 described by Perloff et al. (1964). Each gynecological clinic decided on the indications for artificial insemination. Insemination was usually done twice in each cycle, namely 2 days before and on the day of expected ovulation. Treatment was continued for a maxim of 9 cycles. Of the 30 women treated, 22 became pregnant. The mean treatment period before conception was 3.4 cycles, while the mean period of insemination for all patients was 4.5 cycles. 2 pregnancies ended in miscarriage, 10 patients were delivered of normal infants, and 10 are still pregnant.

During the past 25 years there has been an increasing activity in the search for immune reactions with anticonceptional effects. The interest has been stimulated by the need to explain infertility in couples with otherwise unexplained infertility and by a demand for new methods of fertility regulation.

Fourteen consecutive patients (mean gestational age 18.1 weeks, range 15-23 weeks) referred for therapeutic termination of pregnancy were induced into abortion by intra-amniotic PGF2 alpha 40 mg followed by oxytocin stimulation. 14 other patients (mean gestational age 17.9 weeks, range 15-23 weeks) were pretreated with intracervical PGE2 1.0 mg in gel for 4 h prior to induction of abortion with intra-amniotic PGF2 alpha 40 mg without further stimulation. The induction-abortion interval for patients treated with intra-amniotic PGF2 alpha and oxytocin, was 19.1 +/- 2.94 h (+/- SE, n = 14) with a success rate of 80% after 24 h. After pretreatment with intracervical PGE2 1.0 mg in viscous gel, intra-amniotic PGF2 alpha 40 mg induced abortion after 11.2 +/- 1.12 h (+/- SE, n = 14) with a 100% success rate after 24 h. No systemic side effects of the PGE2 pretreatment were noted. No cervical laceration was observed. The results need further confirmation, but still suggest cervical priming with intracervical PGE2 1.0 mg in gel and subsequent induction of abortion by intra-amniotic PGF2 alpha 40 mg as an attractive principle for 2nd trimester abortion.