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We address the question of whether protoplanetary discs around low mass stars (e.g. Mdwarfs) may be longer lived than their solar-type counterpa rts. This question is particularly relevant to assess the planet-making potential of these low er mass discs. Given the uncertainties inherent to age-dating young stars, we propose an alter native approach that is to analyse the spatial distribution of disc-bearing low-mass stars an d compare it to that of disc-bearing solar-type stars in the same cluster. A significant age di fference between the two populations should be reflected in their average nearest neighbour dista nce (normalised to the number of sources), where the older population should appear more spread out. To this aim, we perform a Minimum Spanning Tree (MST) analysis on the spatial distribution of disc-bearing young stellar objects (YSOs) in six n earby low mass star forming regions. We find no evidence for significant age di fferences between the disc-bearing low-mass (later than M2) and ’solar-type’ (earlier than M2) stars in t hese regions. We model our results by constructing and analysing synthetic fractal distribut ions that we evolve for typical values of the velocity dispersions. A comparison of simple models to our MST analysis suggests that the lifetime of discs around M-stars is similar to that of dis cs around solar-type stars. Furthermore, a model-independent spatial analysis of the observations robustly shows that any age differences between the two samples must be smaller than the average age difference between disc-bearing classical T-Tauri stars and disc-less Weak-L ined T-Tauri stars.

We study the resolved stellar populations of dwarf galaxies in the nearby Centaurus A/M83 group of galaxies. Our goal is to characterize their evolutionary history and to investigate eventual similarities or differences with the dwarf population in other group environments. This work presents the analysis of five late-type (irregular) dwarfs found in the vicinity of the giant spiral M83. Using archival HST/ACS data, we perform synthetic color-magnitude diagram modeling to derive the star formation histories of these late-type dwarfs. The target objects show heterogeneous star formation histories, with average star formation rates of 0.08 to 0.70x10^{-2} M_odot/yr. Some of them present prolonged, global bursts of star formation (~300-500 Myr). The studied galaxies are all metal-poor ([Fe/H] ~-1.4). We further investigate the spatial extent of different stellar populations, finding that the young stars show a clumpy distribution, as opposed to the smooth, broad extent of the old ones. The actively star forming regions have sizes of ~100 pc and lifetimes of >~100 Myr, thus suggesting a stochastic star formation mode for the target dwarf irregular galaxies. The galaxies formed ~20% to 70% of their stars more than ~7 Gyr ago. The studied dwarfs have average star formation rates slightly higher than their analogues in the Local Group, but comparable to those in the M81 group. Our preliminary sample indicates that the neutral gas content of the target dwarfs does seem to be affected by the group environment: galaxies within a denser region have a much lower M_HI/ than the isolated ones, meaning that they will exhaust their gas reservoir more quickly., Comment: 20 pages, 12 figures; accepted for publication in A&A

We report a case of late type III B endoleak from a fabric tear in the main body of a Zenith bifurcated stent-graft approximately 19 months after implantation. A follow-up computed tomography (CT) scan showed gradual growth in the size of the aneurysm, but no apparent endoleak was recognized. However, the CT scan had demonstrated a mosaic pattern in the aneurysm sac, which could indicate an endoleak from a fabric tear. The defect was repaired by implantation of body extensions, but the patient died 5 h after the procedure.

We present the discovery of five late-type T dwarfs identified with the Wide-field Infrared Survey Explorer (WISE). Low-resolution near-infrared spectroscopy obtained with the Magellan Folded-port InfraRed Echellette (FIRE) reveal strong water and methane absorption in all five sources, and spectral indices and comparison to spectral templates indicate classifications ranging from T5.5 to T8.5:. The spectrum of the latest-type source, WISE J1812+2721, is an excellent match to that of the T8.5 companion brown dwarf Wolf 940B. WISE-based spectrophotometric distance estimates place these T dwarfs at 12-13 pc from the Sun, assuming they are single. Preliminary fits of the spectral data to the atmosphere models of Saumon & Marley indicate effective temperatures ranging from 600 K to 930 K, both cloudy and cloud-free atmospheres, and a broad range of ages and masses. In particular, two sources show evidence of both low surface gravity and cloudy atmospheres, tentatively supporting a trend noted in other young brown dwarfs and exoplanets. In contrast, the high proper motion T dwarf WISE J2018-7423 exhibits a suppressed K-band peak and blue spectrophotometric J-K colors indicative of an old, massive brown dwarf; however, it lacks the broadened Y-band peak seen in metal-poor counterparts. These results illustrate the broad diversity of low-temperature brown dwarfs that will be uncovered with WISE., 19 pages, 13 figures; accepted for publication to ApJ

Convection plays an essential role in the emerging intensity for many stars that will be observed by Gaia. Convective-related surface structures affect the shape, shift, and asymmetry of absorption lines, the phocentric and photometric variability causing bias in Gaia measurements. Regarding the importance of Gaia mission and its goals, it is mandatory to have the best models of the observed stars. 3D time-dependent hydrodynamical simulations of surface convection are crucial to model the photosphere of late type stars in a very realistic way. These simulations are an important tool to correct the radial velocities and better estimates the parallaxes and photometric variability., Accepted for publication in the Journal of Physics, Conference Series. Proceedings of the GREAT-ESF Workshop on "Stellar Atmospheres in the Gaia Era."

Void galaxies, residing within the deepest underdensities of the Cosmic Web, present an ideal population for the study of galaxy formation and evolution in an environment undisturbed by the complex processes modifying galaxies in clusters and groups, as well as provide an observational test for theories of cosmological structure formation. We have completed a pilot survey for the HI imaging aspects of a new Void Galaxy Survey (VGS), imaging 15 void galaxies in HI in local (d < 100 Mpc) voids. HI masses range from 3.5 x 10^8 to 3.8 x 10^9 M_sun, with one nondetection with an upper limit of 2.1 x 10^8 M_sun. Our galaxies were selected using a structural and geometric technique to produce a sample that is purely environmentally selected and uniformly represents the void galaxy population. In addition, we use a powerful new backend of the Westerbork Synthesis Radio Telescope that allows us to probe a large volume around each targeted galaxy, simultaneously providing an environmentally constrained sample of fore- and background control sample of galaxies while still resolving individual galaxy kinematics and detecting faint companions in HI. This small sample makes up a surprisingly interesting collection of perturbed and interacting galaxies, all with small stellar disks. Four galaxies have significantly perturbed HI disks, five have previously unidentified companions at distances ranging from 50 to 200 kpc, two are in interacting systems, and one was found to have a polar HI disk. Our initial findings suggest void galaxies are a gas-rich, dynamic population which present evidence of ongoing gas accretion, major and minor interactions, and filamentary alignment despite the surrounding underdense environment., 53 pages, 18 figures, accepted for publication in AJ. High resolution available at http://www.astro.columbia.edu/~keejo/kreckel2010.pdf

Revised orbits and system masses are presented for the following 6 visual double stars: WDS 01259-4754 (RST 33), WDS 16057-3252 (SEE 264), WDS 17575+1058 (BU 1299 AB), WDS 19471-0809 (A 108), WDS 21000+4004 (KUI 103), and WDS 22329+5348 (KUI 112 Aa). In all of these systems, at least one component is of the late-type and the latest observations were made using speckle or CCD techniques. Total system masses were calculated in each case from the orbital period and semiaxis major together with the updated Hipparcos parallax, except in the cases for which there were no Hipparcos data or when these values were not precise. © 2011 American Institute of Physics.

Using VIMOS (VLT) we carried out a spectroscopic survey around seven late-type spiral galaxies and we discovered 55 satellites. After obtaining the radial velocities and spatial distribution of the satellites, we analyze their properties.

We have studied the molecular gas in the vicinity of low-luminosity active galactic nuclei (AGNs) in three bulge-less spiral galaxies: NGC 1042, NGC 4178, and NGC 4395. The (1-0) and (2-1) transitions of gaseous carbon monoxide (CO) are clearly detected within the central kpc of all three galaxies. In the case of NGC 4395, this constitutes the first reported detection of CO. In general, the CO emission is faint, as may be expected from their less-than-spectacular star formation activity. Interestingly, however, both face-on galaxies in our sample (which allow an unimpeded view of their nucleus) show an elevated intensity ratio CO(2-1)/CO(1-0) when compared to similar late-type spirals without an AGN. We discuss that this is unlikely due to a very compact CO source. Instead, we speculate that even energetically weak AGN can impact the physical state of the surrounding gas. We do not detect any tracers of dense molecular gas such as HCN or HCO+, but the sensitivity of our observations allows us to establish upper limits that lie at the low end of the range observed in more energetic AGN. The derived gas density is less than n(H2)\approx 2e03 cm^-3 which is significantly lower than in most other nearby galaxies. The scarcity of dense gas suggests that the conditions for star formation are poor in these nuclei., Accepted for publication in A&A. 8 pages, 5 figures

Magnitudes of the volume-averaged magnetic field have been derived for a representative sample of 146 late-type galaxies using the minimum-energy condition and a simple model for the distribution of radio-emitting plasma within these galaxies. The distribution of derived magnetic fields is narrow (B eq = 0.29 ± 0.11 nT) and skewed to higher values. There is little or no dependence of the derived magnetic field on galactic type, although the archetypal starburst M82 is anomalous. We find no correlation between the scatter in the far-infrared/radio correlation and variation in the derived strength of the magnetic field

This report deals with the rotational history of late-type stars subsequent to their reaching the main sequence. The question of relevance to this Symposium is whether detailed comparison of magnetic braking theory with observations of young stellar clusters will yield any constraints on dynamo activity, in particular on the relation between the surface field strength Bs and the angular velocity ω.

We have constructed a model to calculate in a synthetic way the evolution of stars on the asymptotic giant branch (AGB). The evolution is started at the first thermal pulse (TP) and is terminated when the envelope mass has been lost due to mass loss or when the core mass reaches the Chandrasekhar mass.Our model is more realistic than previous synthetic evolution models in that more physics has been included. The variation of the luminosity during the interpulse period is taken into account as well as the fact that, initially, the first few pulses are not yet at full amplitude and that the luminosity is lower than given by the standard core-mass-luminosity relations. Most of the relations used are metallicity dependent to be able to make a realistic comparison with stars of different metallicity. The effects of first, second and third dredge-up are taken into account. The effect of hot bottom burning (HBB) is included in an approximate way. Mass loss on the AGB is included through a Reimers Law. We also included mass loss prior to the AGB.The free parameters in our calculations are the minimum core mass for dredge-up (M(c)min), the third dredge-up efficiency (lambda) and three mass loss scaling parameters (eta(RGB), eta(EAGB), eta(AGB).The model has been applied to the LMC using a recent determination of the age-metallicity and star formation rate (SFR) for the LMC. The observed carbon star luminosity function and the observed ratio of oxygen-rich to carbon-rich AGB stars in the LMC acted as constraints to the model.Several models are calculated to demonstrate the effects of the various parameters. A model with M(c)min = 0.58M., lambda = 0.75, eta(RGB) = 0-86, eta(AGB) = eta(EAGB) = 5, including HBB reproduces the observations quite well. It is possible that the amount of carbon formed after a TP is higher than the standard value of X12 = 0.22. As long as lambdaX12=0.165 the model fits the observations. It is difficult to discriminate between a higher X12 and a higher lambda. Third dredge-up needs to be more efficient and must start at lower core masses than commonly predicted to account for the observed carbon star LF. It is suggested that evolutionary calculations have been performed with mixing-length parameters which are too small.The adopted mass loss rate coefficients correspond to a pre-AGB mass loss of 0.20M. for a 1M. and 1.8M. for a 5M. star. The low mass stars lose this on the RGB, the high mass stars in the core helium burning phase when they reach high luminosities before the TP-AGB. The Reimers coefficient on the AGB (eta(AGB) = 5) corresponds to a mass loss rate of 1.0 10(-6) M. yr-1 at the first TP for an initially 1 M. star with LMC abundances.These high mass loss rates are necessary to fit the initial-final mass relation and the high luminosity tail of the carbon star LF. The lifetime of the massive stars with these high mass loss rates are in good agreement with the observed number of massive AGB stars and their progenitors, the Cepheid variables. We suggest that the core mass at the first TP for massive stars has previously been overestimated because their evolution was calculated neglecting pre-AGB mass loss.Observationally the distribution of C-13 enriched carbon stars in the LMC is bimodal. There is a small number (approximately 0.1%) of high-luminosity (M(bol) - 4.75) J-type stars. The difference in relative numbers as well as the gap in luminosity between the two distributions suggst a different evolutionary origin. The low-luminosity J-type stars may be related to the R-stars in the Galactic bulge which have luminosities between 0 less than or similar to M(bol) less than or similar to - 3 indicating an origin at luminosities below the AGB.The small number of high-luminosity J-type carbon stars can be explained by HBB. Given the uncertainty in the observed LF and our approximate treatment of HBB the agreement is good. We predict that about 1 % of M and S stars are enriched in C-13 (and N-14).We considered the effect of ''obscuration'', when stars lose so much mass that they become optically invisible. Based on V-band, I-band and IRAS data of Reid et al. (1990) and a radiative transfer model we find that at most 3% of all carbon stars brighter than M(bol) = - 6 could have been missed in optical surveys. Using our model we derive that the overall effect of obscuration of carbon stars is negligible (approximately 0.1%).The predicted average final mass (M(f) = 0.59M.) is in good agreement with the observed value (0.60 +/- 0.02M.). We predict for our LMC model that stars with initial masses larger than 1.2-1.4M. turn into carbon stars directly and that stars initially more massive than about 1.5M. pass through an intermediate S-star phase before becoming carbon stars. This is consistent with the observation of carbon stars and S-stars in LMC clusters.The predicted birth rate of AGB stars is found to be in agreement with the death rate of Cepheids and the clump stars. The birth rate of planetary nebulae (PN) is a factor of 2 lower than the death rate of AGB stars suggesting that low mass stars (M less than or similar 1.1 M.) may not become PN.

We explore the shape of the galaxy luminosity function (LF) in groups of different mass by creating composite LFs over large numbers of groups. Following previous work using total group luminosity as the mass indicator, here we split our groups by multiplicity and by estimated virial (group halo) mass, and consider red (passive) and blue (star forming) galaxies separately. In addition we utilise two different group catalogues (2PIGG and Yang et al.) in order to ascertain the impact of the specific grouping algorithm and further investigate the environmental effects via variations in the LF with position in groups. Our main results are that LFs show a steepening faint end for early type galaxies as a function of group mass/ multiplicity, with a much suppressed trend (evident only in high mass groups) for late type galaxies. Variations between LFs as a function of group mass are robust irrespective of which grouping catalogue is used, and broadly speaking what method for determining group `mass' is used. We find in particular that there is a significant deficit of low-mass passive galaxies in low multiplicity groups, as seen in high redshift clusters. Further to this, the variation in the LF appears to only occur in the central regions of systems, and in fact seems to be most strongly dependent on the position in the group relative to the virial radius. Finally, distance-rank magnitude relations were considered. Only the Yang groups demonstrated any evidence of a correlation between a galaxy's position relative to the brightest group member and its luminosity. 2PIGG possessed no such gradient, the conclusion being the FOF algorithm suppresses the signal for weak luminosity--position trends and the Yang grouping algorithm naturally enhances it., 20 pages, 29 figures, accepted for submission to MNRAS

We report a case of a patient who had a type A aortic dissection after previous coronary bypass grafting. The in-situ right mammary artery had been anastomosed with the left anterior descending artery, the left mammary artery had been anastomosed to the obtuse marginal, and a vein graft had been used for the right coronary artery. All grafts were patent. The patients underwent a Bentall procedure on perfused heart. (J Card Surg 2010;25:330-332)

We observed the microlensing event MOA-2007-BLG-192 at high angular resolution in JHKs with the NACO adaptive optics system on the VLT while the object was still amplified by a factor 1.23 and then at baseline 18 months later. We analyzed and calibrated the NACO photometry in the standard 2MASS system in order to accurately constrain the source and the lens star fluxes. We detect light from the host star of MOA-2007-BLG-192Lb, which significantly reduces the uncertainties in its char- acteristics as compared to earlier analyses. We find that MOA-2007-BLG-192L is most likely a very low mass late type M-dwarf (0.084 [+0.015] [-0.012] M\odot) at a distance of 660 [+100] [-70] pc orbited by a 3.2 [+5.2] [-1.8] M\oplus super-Earth at 0.66 [+0.51] [-0.22] AU. We then discuss the properties of this cold planetary system., Comment: published version A&A 540, A78 (2012) A&A, 10 pages, 7 Figures

Using recent laboratory data of FeH molecular lines we attempt to identify the FeH absorption lines in the one-micron spectral region of late type stars, M dwarfs, M giants, S and C stars. The λ9910 absorption features in the spectrum of R Gem among the observed cool stars are identified as the FeH (0, 0) band lines. Results of our identifications are interpreted in view of the variation of C/O ratio in cool stars based on dissociation equilibrium theory. From our conclusion the appearances of absorption lines due to the metallic hydrides are discussed for cool stars.

The existing and new observing techniques for combined speckle–spectroscopic studies of binary stars are briefly reviewed. The late–type dwarf stars are particularly rewarding since simultaneous spatial and spectroscopic resolution is possible for a large number of systems. A list of new candidates for the interferometric resolution is given. These studies can make an important contribution to the data on stellar masses and also provide some insight into the binary formation mechanisms when applied to multiple systems.

We compare the abundances of various chemical species as derived with 3D hydrodynamical and classical 1D stellar atmosphere codes in a late-type giant characterized by T_eff=3640K, log g = 1.0, [M/H] = 0.0. For this particular set of atmospheric parameters the 3D-1D abundance differences are generally small for neutral atoms and molecules but they may reach up to 0.3-0.4 dex in case of ions. The 3D-1D differences generally become increasingly more negative at higher excitation potentials and are typically largest in the optical wavelength range. Their sign can be both positive and negative, and depends on the excitation potential and wavelength of a given spectral line. While our results obtained with this particular late-type giant model suggest that 1D stellar atmosphere models may be safe to use with neutral atoms and molecules, care should be taken if they are exploited with ions., Comment: Poster presented at the IAU Symposium 265 "Chemical Abundances in the Universe: Connecting First Stars to Planets", Rio de Janeiro, 10-14 August 2009; 2 pages, 1 figure

We have then searched for preferential orientations of faint galaxies in the Coma cluster (down I_Vega~-11.5). By applying a deconvolution method to deep u* and I band images of the Coma cluster, we were able to recover orientations down to faint magnitudes. No preferential orientations are found in more than 95% of the cluster, and the brighter the galaxies, the fewer preferential orientations. The minor axes of late type galaxies are radially oriented along a northeast -southwest direction and are oriented north-south in the western X-ray sub- structures. For early type galaxies, in the western regions showing significant preferential orientations, galaxy major axes are oriented perpendicularly to the north-south direction. In the eastern significant region and close to NGC 4889, galaxy major axes also point toward the 2 cluster dominant galaxies. In the southern significant regions, galaxy planes are tangential with respect to the clustercentric direction, except close to (alpha=194.8, delta=27.65) where the orientation is close to -15deg. Part of the orientations of the minor axes of late type galaxies and of the major axes of early type galaxies can be explained by a tidal torque model applied to cosmological filaments and local merging directions. Another part (close to NGC4889) can be accounted for by collimated infalls. For early type galaxies, the (alpha=194.8, delta=27.65) region shows orientations that probably result from processes involving induced star formation., Accepted in A&A

We have obtained high resolution optical spectra for a sample of more than 190 early‐ and mid‐type M‐stars with FOCES (Calar Alto) and FEROS (La Silla). These data will advance our understanding of the rotation‐activity relation over the mass range where stars become fully convective. From our observations we determined the Hα luminosity, which is directly connected to chromospheric activity. We present preliminary results from our sample.

In vitro tuberization on shoot cultures of early, mid-season, late and very late potatoes was compared. Shoots were grown at 12, 16, or 20 h photoperiods; tuberization was then induced at 0, 8 or 16 h light. In the dark, shoots from early plants initially grown at 16 h consistently set tubers earlier than the other types, whereas the very late line tuberized later and produced significantly fewer tubers. Tuber setting of mid-season plants could not be distinguished from the late type. Tuberization of the very late line was significantly hastened by shortening the photoperiod from 20 h to 12 h during the shoot growth period. Light during tuber induction delayed tuberization. This system may be useful to screen callus-derived plants for maturity, and may also be suitable for in vitro study of the photoperiodic control of tuberization.

Since the photometric UBVRI broadband systems of Johnson and Morgan (1951, 1953), Johnson (1955, 1965) and Cousins (1976) were partly illdefined and have partly been modified over the years, their technical realization at different observatories is problematical. Large differences occur especially in measuring objects with peculiar spectra or strong lines. Therefore, firstly an accurate reconstruction of the UBVRI systems of Johnson and the Cousins systems used at the South African Astronomical Observatory (SAAO), at Cerro Tololo Inter-American Observatory (CTIO) and at Mount Stromlo/Siding Springs Observatory (MSSO) was attempted. The transmissions of the different bands, as well as the possible technical realizations are listed. The data of the Johnson system and the Cousins systems used at SAAO and MSSO were compiled from several publications and new measured transmission curves of the CTIO systems are given. The characteristic wavelengths λ0 have been calculated for all systems. Using flux-calibrated spectra of 75 early and late type stars in the wavelength range 3200-8800 A with a resolution of 10 A, synthetic photometries of the four described systems and that of Bessell (1990) were derived. The transformation relations from the various systems to the original Johnson system are given in and have been compared to the defined relations. The accuracy of the synthetic photometry is ±0.02 mag in V and (B-V), ±0.09 mag in (U-B), and ±0.05 mag in (V-R). The larger error in (U-B) is due to the shortwave uncertainties of the U filter transmissions and the missing spectral information because of UV cut-off of the spectra at λmin > 3200 A. The uncertainties in (V-R) are due to the different R filters in the various systems. No synthetic photometry was possible to derive for the I band, because of missing spectral information at λ > 8800 A. Die technische Realisierung der teilweise bereit vor einigen Jahrzehnten definierten UBVRI-Breitband-Systeme bereitet haufig Schwierigkeiten. Sowohl das von Johnson und Morgan (1951, 1953) und Johnson (1955, 1965) definierte System, wie auch das Cousins- UBVRIc (1976) sind teilweise ungenau definiert oder im Laufe der Jahre modifiziert worden. So kommt es zu Abweichungen bei Messungen an verschiedenen Observatorien, insbesondere bei Objekten, deren Spektrum pekuliar ist oder zumindest stark vom Idealkontinuum der Standardsterne abweicht. Im folgenden wurde deshalb zunachst eine moglichst genaue Rekonstruktion der UBVRI-Systeme von Johnson, sowie der Cousins-Systeme, wie sie am South African Astronomical Observatory (SAAO), am Cerro Tololo Inter-American Observatory (CTIO) und am Mount Stromlo/Siding Springs Observatory (MSSO) verwendet werden, versucht und die Transmissionen der einzelnen Bander aufgelistet und die jeweilige technische Realisierung angegeben. Die Daten fur das Johnson-System und die Cousins-Systeme am SAAO und MSSO wurden dabei aus unterschiedlichen Quellen zusammengetragen, fur das Cousins-System am CTIO werden neue gemessene Filtertransmissionen angegeben. Die charakteristischen Wellenlangen λ0 wurden fur alle Systeme neu bestimmt. Anhand von 75 fluskalibrierten Spektren von Fruh- und Spattypsternen, die im Wellenlangenbereich 3200-8800 A mit einer Auflosung von 10 A vorlagen, wurden fur die zuvor genannten photometrischen Systeme und fur ein von Bessell (1990) rekonstruiertes System synthetische Photometrien gewonnen. Es werden die Transformationsbeziehungen zwischen den verschiedenen Systemen und dem Johnson-Original-ystem angegeben und mit den definierten verglichen. Die Genauigkeiten der synthetischen Photometrien betragen ±0.02 mag fur V und (B-V), ±0.09 mag fur (U-B) und ±0.05 mag fur (V-R). Die grosere Unsicherheit fur (U-B) ergibt sich aus der Unsicherheit der Filtertransmissionen im Kurzwelligen sowie aus dem Fehlen von Informationen im Spektrum bei zu langwelliger Grenzwellenlange λmin, die Fehler der (V-R)-Transformationen sind durch die unterschiedlichen R-Filter begrundet.

Objective To clarify the differences in clinical characteristics between early and late ovarian hyperstimulation syndrome (OHSS). Design Retrospective study. Setting Tertiary university hospital. Patient(s) Ninety-four patients/cycles hospitalized for moderate-to-severe OHSS after controlled ovarian hyperstimulation (COH) for IVF/intracytoplasmic sperm injection (ICSI); early type (n = 69) and late type (n = 25). Intervention(s) None. Main Outcome Measure(s) The COH and pregnancy outcomes, preclinical and clinical miscarriage rate, and hospital courses. Result(s) Serum E 2 levels (4,955.5 ± 3,268.5 pg/mL vs. 2,340.8 ± 960.6 pg/mL) and the number of follicles ≥11 mm on day of hCG administration (15.9 ± 6.0 vs. 13.0 ± 4.0), and the number of oocytes retrieved (21.9 ± 9.7 vs. 13.2 ± 5.9) were significantly higher in the early OHSS group compared with the late OHSS group. Clinical pregnancy rate (PR) was significantly higher in the late OHSS group (23.6% [13/55] vs. 92.0% [23/25]). There were no significant differences in multiple PR and disease severity between the two groups. Conclusion(s) Early OHSS is associated with excessive ovarian response to gonadotropin stimulation, whereas late OHSS is closely associated with conception cycle. Our findings do not support that late OHSS is more severe and closely associated with multiple pregnancies compared with early OHSS.

This study of 117 low-redshift Im and Sm galaxies investigates the star formation rates of late-type galaxies, to determine whether they are quasi-continuous or dominated by bursts with quiescent interludes. We analyse the distribution of star formation timescales (stellar masses/star formation rates) for the entire sample, and of gas depletion timescales for those galaxies with gas mass measurements. We find that, on average, the late-type galaxies studied could have produced their total stellar masses by an extrapolation of their current star formation activity over a period of just under a Hubble time. This is not the case for a comparison sample of earlier-type galaxies, even those with disk-dominated morphologies and similar total stellar masses to the late-type galaxies. The earlier-type galaxies are on average forming their stars more slowly at present than the average rate over their past histories. No totally quiescent Im or Sm galaxies are found, and although some evidence of intrinsic variation in the star formation rate with time is found, this is typically less than a factor of 2 increase or decrease relative to the mean level. The Im and Sm galaxies have extensive gas reservoirs and can maintain star formation at the current rate for more than another Hubble time. The average spatial distribution of star formation in the Im galaxies, and to a lesser extent the Sm galaxies, is very similar to that of the older stellar population traced by the red light., 8 pages, 7 figures, accepted for publication in Astronomy & Astrophysics

Optically thick lines in the UV spectra of late type stars obey a Wilson-Bappu type relationship. Optically thin lines reveal no width-luminosity relationship. Consequently, there is no systematic variation in Doppler broadening with stellar luminosity.

The purpose of this project is to obtain optical identifications of x-ray luminous late type stars. Our approach consists of detecting position coincidences between unidentified x-ray sources and stars for which (V-I) > 3 mag., as obtained from the Near Infrared Photographic Sky Survey (NIPSS) database. Objects with effective temperatures below 3000 K are the most frequent counterparts found by this method at high galactic latitudes (Craine 1987). In this paper we present a derivation of the detection limits of the NIPSS relevant to the lower main sequence dwarf stars. Significantly, M8 or M9 stars with apparent V magnitudes below the detection limit may still appear on the NIPSS I band photographs, where the detection limit is extended to pre-main sequence objects of about 0.03 solar luminosity.

In the past several years, a growing body of observational data has become available on stellar chromospheres, transition regions and coronae. Most of these data are scattered throughout the scientific literature. More importantly, the data have been obtained using different instruments and reduction techniques and are often on different scales. In order to make these data more readily available, we have started a long-term project of collecting absolute surface fluxes and/or luminosities for various indicators of chromospheres, transition regions and coronae of stars of spectral types later than F5. Selected indicators include Ca II K and Mg IIk chromospheric fluxes, transition region lines of C IV, Si IV and N V, and coronal X-ray fluxes. For each indicator, an effort is made to convert the available data to one absolute scale and to estimate systematic differences between different authors. These data may be useful for a variety of purposes including statistical studies, correlations between observables, and planning of future observational campaigns. As an example of our approach we present a preliminary catalog of absolute surface fluxes in the Ca II K line. We also discuss future developments of the project.

We discuss correlations between broadband linear polarization, intrinsic stellar parameters, and Ca 11 H+K emission in G and K dwarfs.

We report on an analysis of flaring and BY-Draconis type variability on the Balmer emission line star, Gliese 867B. The time-averaged flare energy in the Johnson 1-band is similar to that measured in 1977 and 1978. A variation of 0.15 magnitudes was observed in the V-band with a period l.95 days.

A correlation between the Mg h & k flux and the rotation period for main-sequence F to K stars has been extended to include all dMe stars with known rotational periods. It is shown that the relationship proposed by Hartmann et al for F to K stars does extend to the dMe stars, although there is more scatter. This is in part due to our inability to use the parameter representing the convective-overturn time.

We present a very preliminary and simplified analysis designed to measure photospheric magnetic fields in late-type stars, using the FeI 5247.06 A and 5250.22 A lines. We show how the use of the equivalent widths of the lines and differences in their depth can give a rapid estimation of the magnetic flux.

An account of the development of the study of stellar envelopes by means of maser lines is given.

AIMS: Compact groups of galaxies are excellent laboratories for studying galaxy interactions and their effects on the evolution of galaxies. In particular, dynamically young systems, with a large fraction of interacting, late type galaxies, have so far escaped proper studies in the X-ray band and their hot intergalactic medium properties are virtually unknown. Motivated by this lack of knowledge, we present a detailed investigation here of the X-ray properties of such a dynamically young system. METHODS: We obtained XMM-Newton observations of one spiral-only system in the new southern compact group catalogue: SCG0018-4854. We present here the results of the data analysis and discuss them in comparison with the few other similar systems also studied in the X-ray band. RESULTS: The 4 members of SCG0018-4854 emit at a level comparable to what is expected based on their optical properties. We detect the low level diffuse emission between galaxies, which is most likely due to the presence of the intergalactic medium. Compared to other spiral--only groups, this could be the coolest system detected so far, although the measurements have large uncertainties. These results indicate that high quality deep X-ray observations are needed to allow a proper study of the properties of the potential well of dynamically young systems, before more general conclusions can be drawn on their average characteristics., Accepted for publication in A&A

The X-ray spectra of late type stars can generally be well fitted by a two temperature component model of the corona. We fnd that the temperature of both components are strong functions of stellar age, although the temperature of the hotter plasma in the corona shows a larger scatter and is probably affected by the activity of stars, such as flares. We confirm the power-law decay of the temperature of the hot plasma, but the temperature of the cool component decays linearly with log (age)., 6 pages, 2 figures, typo in published paper: Sana et al. (2006) should be changed as Sana et al. (2007)

We report a case of a late type III endoleak from a hole in the fabric of the main body of a Zenith bifurcated endograft 7 years after implantation. Abdominal pain and a rapidly expanding aneurysm were eventually followed by rupture. The defect was detected at open surgery, whereas no evidence of endoleak was found at preoperative computed tomography (CT) or angiogram. The defect was repaired by a relining procedure with an Excluder stent graft. The patient, however, died 3 weeks after admission.

The low-mass end of the supermassive black hole mass function is unknown and difficult to determine. Here we discuss our successful program to find active nuclei of late type "normal" galaxies using X-ray detections and multiwavelength identifications. We conclude that most of the Chandra detected nuclear X-ray sources are AGNs. We then outline methods of black hole mass determination when broad emission lines are unobservable., Comment: 7 pages. To appear in the proceedings of the Second Kolkata Conference on Observational Evidence for Black Holes, Kolkata, February 2008

Aims: To determine durability and need for reinterventions after endovascular stent-graft placement in atherosclerotic aneurysms involving the descending aorta. Patients and methods: We performed a prospective follow-up analysis of a consecutive series of patients (n=79) undergoing endovascular stent-graft placement due to atherosclerotic aneurysms involving the descending aorta between 1996 and 2006. Acute aortic syndromes were excluded from this analysis. Mean follow-up was 42 months (range, 1–108 months). The following events were collected: In-hospital mortality, occurrence of early and late endoleaks, reintervention due to early and late endoleaks as well as survival. Results: In-hospital mortality was 6.3% (n=5), two of these patients underwent emergent treatment. Early type I and III endoleaks were observed in 29% of patients (n=23). Assisted primary endoleak rate was 11%. Late type I or III endoleaks occurred in 21% (n=17). Overall actuarial survival was 96%, 86% and 69% at 1, 3 and 5 years, respectively. Event-free survival was 90%, 82% and 65% at 1, 3 and 5 years, respectively. Cox proportional hazard analysis revealed a short proximal landing zone as well as a high number of stent-grafts used as independent risk factors for early and late endoleak formation. Late endoleak formation was an independent predictor of survival. Conclusions: Durability of endovascular stent-graft placement in atherosclerotic aneurysms involving the descending aorta is satisfying. Extensive gaining of landing zones is a prerequisite of early and late success. Further clinical investigations are warranted to evaluate long-term durability of this attracitve treatment modality.

Using the SDSS DR4 group catalogue of Yang et al. (2007), we investigate sizes, concentrations, colour gradients and surface brightness profiles of central and satellite galaxies. We compare central and satellite galaxies at fixed stellar mass, in order to disentangle environmental from stellar mass dependencies. Early and late type galaxies are defined according to concentration. We find that at fixed stellar mass, late type satellite galaxies have smaller radii and larger concentrations than late type central galaxies. No such differences are found for early-type galaxies. We have also constructed surface brightness and colour profiles for the central and satellite galaxies in our sample. We find that late-type satellite galaxies have a lower surface brightness and redder colours than late-type central galaxies. We show that all observed differences between satellite and central galaxies can be explained by a simple fading model, in which the star formation in the disk decreases over timescales of 2-3 Gyr after a galaxy becomes a satellite. Processes that induce strong morphological changes (e.g. harassment) and processes that strip the galaxy of its entire ISM need not to be invoked in order to explain the environmental dependencies we find., Comment: 17 pages, 13 figures, MNRAS accepted. Discussion has been extended and includes now the effects of dust and the colour profiles of subpopulations. Some references added

We have examined the relationship between rotation and activity in 14 late-type (M6-M7) M dwarfs, using high resolution spectra taken at the Keck Observatory and flux-calibrated spectra from the Sloan Digital Sky Survey. Most are inactive at a spectral type where H-alpha emission has previously seen to be very common. We used the cross-correlation technique to quantify the rotational broadening; six of the stars in our sample have vsini>3.5 km/s. Three of these stars do not exhibit H-alpha emission, despite rotating at velocities where previous work has observed strong levels of magnetic field and stellar activity. Our results suggest that rotation and activity in late-type M dwarfs may not always be linked, and open several additional possibilities including a rotation dependant activity threshold, or a Maunder-minimum phenomenon in fully convective stars., 4 pages, 2 figures, to appear in proceedings of Cool Stars 15

The authors report a case of a delayed type IIIb endoleak with sac expansion 6 years after an endovascular repair of an abdominal aortic aneurysm with an Ancure bifurcated stent-graft. The presumed etiology of the leak was secondary to erosion of the main body graft material by metal stents placed within the graft to correct kinking of the iliac limbs at the index operation. The endoleak was successfully treated by endovascular means with an aortouni-iliac device, contralateral iliac plug followed by a femoral-to-femoral bypass graft.

We present new Space Telescope Imaging Spectrograph (STIS) observations of three spiral galaxies, NGC 4303, NGC 3310 and NGC 4258. The bright optical emission lines H$\alpha$ $\lambda$ $6564 \AA$, [NII] $\lambda$$\lambda$ $6549,6585 \AA$ and [SII] $\lambda$$\lambda$ $ 6718,6732 \AA$ were used to study the kinematics of the ionized gas in the nuclear region of each galaxy with a $\sim 0.07\arcsec$ spatial resolution. In NGC 3310, the observed gas kinematics is well matched by a circularly rotating disk model but we are only able to set an upper limit to the BH mass which, taking into account the allowed disk inclinations, varies in the range $5.0 \times 10^{6} - 4.2 \times 10^{7} M_{\odot}$ at the 95% confidence level. In NGC 4303 the kinematical data require the presence of a BH with mass $M_{BH}=(5.0)^{+0.87}_{-2.26}\times 10^{6}M_{\odot}$ (for a disk inclination $i=70$ deg).In NGC 4258, the observed kinematics require the presence of a black hole with $M_{BH}= (7.9)^{+6.2}_{-3.5} \times 10^{7}M_{\odot}$ ($i=60$ deg). This result is in good agreement with the published value $(3.9 \pm 0.1) \times 10^{7} M_{\odot}$, derived from $H_{2}O$-maser observations. Our attempt at measuring BH masses in these 3 late type Sbc spiral galaxies has shown that these measurements are very challenging and at the limit of the highest spatial resolution currently available. Nonetheless our estimates are in good agreement with the scaling relations between black holes and their host spheroids suggesting that (i) they are reliable and (ii) black holes in spiral galaxies follows the same scaling relations as those in more massive early-type galaxies. A crucial test for the gas kinematical method, the correct recovery of the known BH mass in NGC 4258, has been successful. [abridged], Comment: 24 pages, 21 figures, A&A in press

The combination of huge databases of galaxy spectra and advances in evolutionary synthesis models in the past few years has renewed interest in an old question: How to estimate the star formation history of a galaxy out of its integrated spectrum? Fresh approaches to this classical problem are making it possible to extract the best of both worlds, producing exquisite pixel-by-pixel fits to galaxy spectra with state-of-the-art stellar population models while at the same time exploring the fabulous statistics of mega-surveys to derive the star-formation and chemical enrichment histories of different types of galaxies with an unprecedented level of detail. This review covers some of these recent advances, focusing on results for late-type, star-forming galaxies, and outlines some of the issues which will keep us busy in the coming years., To appear in the proceedings of IAU symposium 241, "Stellar Populations as Building Blocks of Galaxies"

We study two dimensional Fabry-Perot interferometric observations of the nearby face-on late-type spiral galaxy, NGC 628. We investigate the role of the individual HII regions together with the large-scale gravitational mechanisms which govern star formation and overall evolution in spiral galaxies. Our kinematical analysis (reinforced by literature maps in HI and CO at lower angular resolution) enables us to verify the presence of an inner rapidly rotating inner disk-like component which we attribute to long term secular evolution of the large-scale spiral arms and oval structure. We find that gas is falling in from the outer parts towards the bluer central regions. This could be an early phase in the formation of a pseudo-bulge. We find signatures of radial motions caused by an m=2 perturbation, which are likely to be responsible for the inflow of material forming the circumnuclear ring and the rapidly rotating inner structure., To appear in the proceedings for IAU symposium 241. "Stellar Populations as Building Blocks of Galaxies", Editors: R.F. Peletier, A. Vazdekis