Limits on additional planetary companions to OGLE-2005-BLG-390L

We investigate constraints on additional planets orbiting the distant M-dwarf star OGLE-2005-BLG-390L, around which photometric microlensing data has revealed the existence of the sub-Neptune-mass planet OGLE-2005-BLG-390Lb. We specifically aim to study potential Jovian companions and compare our findings with predictions from core-accretion and disc-instability models of planet formation. We also obtain an estimate of the detection probability for sub-Neptune mass planets similar to OGLE-2005-BLG-390Lb using a simplified simulation of a microlensing experiment. We compute the efficiency of our photometric data for detecting additional planets around OGLE-2005-BLG-390L, as a function of the microlensing model parameters and convert it into a function of the orbital axis and planet mass by means of an adopted model of the Milky Way. We find that more than 50 % of potential planets with a mass in excess of 1 M_J between 1.1 and 2.3 AU around OGLE-2005-BLG-390L would have revealed their existence, whereas for gas giants above 3 M_J in orbits between 1.5 and 2.2 AU, the detection efficiency reaches 70 %; however, no such companion was observed. Our photometric microlensing data therefore do not contradict the existence of gas giant planets at any separation orbiting OGLE-2005-BLG-390L. Furthermore we find a detection probability for an OGLE-2005-BLG-390Lb-like planet of around 2-5 %. In agreement with current planet formation theories, this quantitatively supports the prediction that sub-Neptune mass planets are common around low-mass stars.Comment: 10 pages, 4 figures, accepted by A&

OGLE-2005-BLG-071Lb, the Most Massive M-Dwarf Planetary Companion?

We combine all available information to constrain the nature of OGLE-2005-BLG-071Lb, the second planet discovered by microlensing and the first in a high-magnification event. These include photometric and astrometric measurements from Hubble Space Telescope, as well as constraints from higher order effects extracted from the ground-based light curve, such as microlens parallax, planetary orbital motion and finite-source effects. Our primary analysis leads to the conclusion that the host of Jovian planet OGLE-2005-BLG-071Lb is an M dwarf in the foreground disk with mass M= 0.46 +/- 0.04 Msun, distance D_l = 3.3 +/- 0.4 kpc, and thick-disk kinematics v_LSR ~ 103 km/s. From the best-fit model, the planet has mass M_p = 3.8 +/- 0.4 M_Jup, lies at a projected separation r_perp = 3.6 +/- 0.2 AU from its host and so has an equilibrium temperature of T ~ 55 K, i.e., similar to Neptune. A degenerate model less favored by \Delta\chi^2 = 2.1 (or 2.2, depending on the sign of the impact parameter) gives similar planetary mass M_p = 3.4 +/- 0.4 M_Jup with a smaller projected separation, r_\perp = 2.1 +/- 0.1 AU, and higher equilibrium temperature T ~ 71 K. These results from the primary analysis suggest that OGLE-2005-BLG-071Lb is likely to be the most massive planet yet discovered that is hosted by an M dwarf. However, the formation of such high-mass planetary companions in the outer regions of M-dwarf planetary systems is predicted to be unlikely within the core-accretion scenario. There are a number of caveats to this primary analysis, which assumes (based on real but limited evidence) that the unlensed light coincident with the source is actually due to the lens, that is, the planetary host. However, these caveats could mostly be resolved by a single astrometric measurement a few years after the event.Comment: 51 pages, 12 figures, 3 tables, Published in Ap

Interpretation of Strong Short-Term Central Perturbations in the Light Curves of Moderate-Magnification Microlensing Events

To improve the planet detection efficiency, current planetary microlensing experiments are focused on high-magnification events searching for planetary signals near the peak of lensing light curves. However, it is known that central perturbations can also be produced by binary companions and thus it is important to distinguish planetary signals from those induced by binary companions. In this paper, we analyze the light curves of microlensing events OGLE-2007-BLG-137/MOA-2007-BLG-091, OGLE-2007-BLG-355/MOA-2007-BLG-278, and MOA-2007-BLG-199/OGLE-2007-BLG-419, for all of which exhibit short-term perturbations near the peaks of the light curves. From detailed modeling of the light curves, we find that the perturbations of the events are caused by binary companions rather than planets. From close examination of the light curves combined with the underlying physical geometry of the lens system obtained from modeling, we find that the short time-scale caustic-crossing feature occurring at a low or a moderate base magnification with an additional secondary perturbation is a typical feature of binary-lens events and thus can be used for the discrimination between the binary and planetary interpretations.Comment: 17 pages, 4 figures, 1 tabl

MOA-2009-BLG-387Lb: A massive planet orbiting an M dwarf

We report the discovery of a planet with a high planet-to-star mass ratio in the microlensing event MOA-2009-BLG-387, which exhibited pronounced deviations over a 12-day interval, one of the longest for any planetary event. The host is an M dwarf, with a mass in the range 0.07 M_sun < M_host < 0.49M_sun at 90% confidence. The planet-star mass ratio q = 0.0132 +- 0.003 has been measured extremely well, so at the best-estimated host mass, the planet mass is m_p = 2.6 Jupiter masses for the median host mass, M = 0.19 M_sun. The host mass is determined from two "higher order" microlensing parameters. One of these, the angular Einstein radius \theta_E = 0.31 +- 0.03 mas, is very well measured, but the other (the microlens parallax \pi_E, which is due to the Earth's orbital motion) is highly degenate with the orbital motion of the planet. We statistically resolve the degeneracy between Earth and planet orbital effects by imposing priors from a Galactic model that specifies the positions and velocities of lenses and sources and a Kepler model of orbits. The 90% confidence intervals for the distance, semi-major axis, and period of the planet are 3.5 kpc < D_L < 7.9 kpc, 1.1 AU < a < 2.7AU, and 3.8 yr < P < 7.6 yr, respectively.Comment: 20 pages including 8 figures. A&A 529 102 (2011

Frequency of Solar-Like Systems and of Ice and Gas Giants Beyond the Snow Line from High-Magnification Microlensing Events in 2005-2008

We present the first measurement of planet frequency beyond the "snow line" for planet/star mass-ratios[-4.5<log q<-2]: d^2 N/dlog q/dlog s=(0.36+-0.15)/dex^2 at mean mass ratio q=5e-4, and consistent with being flat in log projected separation, s. Our result is based on a sample of 6 planets detected from intensive follow-up of high-mag (A>200) microlensing events during 2005-8. The sample host stars have typical mass M_host 0.5 Msun, and detection is sensitive to planets over a range of projected separations (R_E/s_max,R_E*s_max), where R_E 3.5 AU sqrt(M_host/Msun) is the Einstein radius and s_max (q/5e-5)^{2/3}, corresponding to deprojected separations ~3 times the "snow line". Though frenetic, the observations constitute a "controlled experiment", which permits measurement of absolute planet frequency. High-mag events are rare, but the high-mag channel is efficient: half of high-mag events were successfully monitored and half of these yielded planet detections. The planet frequency derived from microlensing is a factor 7 larger than from RV studies at factor ~25 smaller separations [2<P<2000 days]. However, this difference is basically consistent with the gradient derived from RV studies (when extrapolated well beyond the separations from which it is measured). This suggests a universal separation distribution across 2 dex in semi-major axis, 2 dex in mass ratio, and 0.3 dex in host mass. Finally, if all planetary systems were "analogs" of the Solar System, our sample would have yielded 18.2 planets (11.4 "Jupiters", 6.4 "Saturns", 0.3 "Uranuses", 0.2 "Neptunes") including 6.1 systems with 2 or more planet detections. This compares to 6 planets including one 2-planet system in the actual sample, implying a first estimate of 1/6 for the frequency of solar-like systems.Comment: 42 pages, 10 figure

Long-Term Blocking of Calcium Channels in mdx Mice Results in Differential Effects on Heart and Skeletal Muscle

The disease mechanisms underlying dystrophin-deficient muscular dystrophy are complex, involving not only muscle membrane fragility, but also dysregulated calcium homeostasis. Specifically, it has been proposed that calcium channels directly initiate a cascade of pathological events by allowing calcium ions to enter the cell. The objective of this study was to investigate the effect of chronically blocking calcium channels with the aminoglycoside antibiotic streptomycin from onset of disease in the mdx mouse model of Duchenne muscular dystrophy (DMD)

Safety of growth hormone replacement in survivors of cancer and intracranial and pituitary tumours: a consensus statement

Growth hormone (GH) has been used for over 35 years, and its safety and efficacy has been studied extensively. Experimental studies showing the permissive role of GH/insulin-like growth factor 1 (IGF-I) in carcinogenesis have raised concerns regarding the safety of GH replacement in children and adults who have received treatment for cancer and those with intracranial and pituitary tumours. A consensus statement was produced to guide decision-making on GH replacement in children and adult survivors of cancer, in those treated for intracranial and pituitary tumours and in patients with increased cancer risk. With the support of the European Society of Endocrinology, the Growth Hormone Research Society convened a Workshop, where 55 international key opinion leaders representing 10 professional societies were invited to participate. This consensus statement utilized: (1) a critical review paper produced before the Workshop, (2) five plenary talks, (3) evidence-based comments from four breakout groups, and (4) discussions during report-back sessions. Current evidence reviewed from the proceedings from the Workshop does not support an association between GH replacement and primary tumour or cancer recurrence. The effect of GH replacement on secondary neoplasia risk is minor compared to host- and tumour treatment-related factors. There is no evidence for an association between GH replacement and increased mortality from cancer amongst GH-deficient childhood cancer survivors. Patients with pituitary tumour or craniopharyngioma remnants receiving GH replacement do not need to be treated or monitored differently than those not receiving GH. GH replacement might be considered in GH-deficient adult cancer survivors in remission after careful individual risk/benefit analysis. In children with cancer predisposition syndromes, GH treatment is generally contraindicated but may be considered cautiously in select patients

Politicising government engagement with corporate social responsibility: “CSR” as an empty signifier

Governments are widely viewed by academics and practitioners (and society more generally) as the key societal actors who are capable of compelling businesses to practice corporate social responsibility (CSR). Arguably, such government involvement could be seen as a technocratic device for encouraging ethical business behaviour. In this paper, we offer a more politicised interpretation of government engagement with CSR where “CSR” is not a desired form of business conduct but an element of discourse that governments can deploy in structuring their relationships with other social actors. We build our argument through a historical analysis of government CSR discourse in the Russian Federation. Laclau and Mouffe's (Hegemony and socialist strategy: Towards a radical democratic politics,Verso Books, London, 1985) social theory of hegemony underpins our research. We find that “CSR” in the Russian government’s discourse served to legitimise its power over large businesses. Using this case, we contribute to wider academic debates by providing fresh empirical evidence that allows the development of critical evaluation tools in relation to governments’ engagement with “CSR”. We find that governments are capable of hijacking CSR for their own self-interested gain. We close the paper by reflecting on the merit of exploring the case of the Russian Federation. As a “non-core”, non-western exemplar, it provides a useful “mirror” with which to reflect on the more widely used test-bed of Western industrial democracies when scrutinising CSR. Based on our findings, we invite other scholars to adopt a more critical, politicised stance when researching the role of governments in relation to CSR in other parts of the world