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Asteroids two-by-two The increased interest in the observation of main-belt asteroids in recent years has led to the identification of tens of asteroid pairs, which follow near-identical orbits around the Sun even though they are not physically bound together. Rotational fission of larger bodies has been hypothesized as a mechanism for their formation, an idea that gains support with some new observations. Theory predicts that the mass ratios of two asteroids in a pair will be than about 0.2 and that as the mass ratio approaches this upper limit, the spin period of the larger body is extended. Accordingly, photometric observations of 35 asteroid pairs reveal none with mass ratios greater than 0.2, and as mass ratios approach 0.2, primary periods grow longer. This suggests that asteroid pairs form by rotational fusion of a parent asteroid into a short-lived proto-binary system. Rotational fission may explain the formation of pairs of asteroids that have similar heliocentric orbits but are not bound together. These authors report photometric observations of a sample of asteroid pairs revealing that the primaries of pairs with mass ratios much less than 0.2 rotate rapidly, near their critical fission frequency. In agreement with crucial predictions, they do not find asteroid pairs with mass ratios larger than 0.2, and as the mass ratio approaches 0.2 the primary period grows long. Pairs of asteroids sharing similar heliocentric orbits, but not bound together, were found recently 1 , 2 , 3 . Backward integrations of their orbits indicated that they separated gently with low relative velocities, but did not provide additional insight into their formation mechanism. A previously hypothesized rotational fission process 4 may explain their formation—critical predictions are that the mass ratios are less than about 0.2 and, as the mass ratio approaches this upper limit, the spin period of the larger body becomes long. Here we report photometric observations of a sample of asteroid pairs, revealing that the primaries of pairs with mass ratios much less than 0.2 rotate rapidly, near their critical fission frequency. As the mass ratio approaches 0.2, the primary period grows long. This occurs as the total energy of the system approaches zero, requiring the asteroid pair to extract an increasing fraction of energy from the primary's spin in order to escape. We do not find asteroid pairs with mass ratios larger than 0.2. Rotationally fissioned systems beyond this limit have insufficient energy to disrupt. We conclude that asteroid pairs are formed by the rotational fission of a parent asteroid into a proto-binary system, which subsequently disrupts under its own internal system dynamics soon after formation.

Perioperative bleeding is a determinant of poor outcome in patients undergoing coronary artery bypass grafting (CABG), but there is a lack of adequate stratification of its severity. The ability of the European registry of Coronary Artery Bypass Grafting (E-CABG), Universal Definition of Perioperative Bleeding (UDPB), Study of Platelet Inhibition and Patient Outcomes (PLATO), Clopidogrel and Aspirin Optimal Dose Usage to Reduce Recurrent Events−Seventh Organization to Assess Strategies in Ischemic Syndromes (CURRENT-OASIS 7), Efficacy and Safety of Subcutaneous Enoxaparin in Non-Q Wave Coronary Events (ESSENCE), and SafeTy and Efficacy of Enoxaparin in Percutaneous coronary intervention patients, an internationaL randomized Evaluation (STEEPLE) bleeding classifications to predict early mortality, stroke, acute kidney injury (AKI) stage 3, and deep sternal wound infection/mediastinitis was investigated in 3,730 patients from the prospective, multicentre E-CABG registry. Increasing grades of the E-CABG, UDPB, PLATO, and CURRENT-OASIS 7 classifications were associated with increasing risks of early mortality, had similar receiver-operating characteristic area under the curves (>0.7), and were predictive also when adjusted for EuroSCORE II. The E-CABG and UDPB classifications had satisfactory area under the curves (>0.6) in predicting stroke, AKI stage 3, and deep sternal wound infection/mediastinitis even when adjusted for EuroSCORE II. The PLATO and CURRENT-OASIS 7 classifications had similar predictive ability for stroke and AKI stage 3 as confirmed by multivariate analysis adjusted for EuroSCORE II but showed inferior ability in predicting severe wound infection compared to the E-CABG and UDPB classifications. The STEEPLE and ESSENCE classifications had a poor ability of predicting all these adverse events. Decision curve analysis showed a benefit of the E-CABG bleeding classification over the other classifications in predicting all adverse events. In conclusion, the E-CABG, UDPB, PLATO, and CURRENT-OASIS 7 bleeding classifications have a satisfactory ability in predicting adverse events after CABG. Decision curve analysis showed that the E-CABG bleeding classification had the best predictive performance.

PSR J10203+0038 is a transitional millisecond pulsar (tMSP) in an eclipsing binary system, which has been observed to switch between the radio loud millisecond pulsar (MSP) and low-mass-X-ray binary (LMXB) states. This behavior offers a great opportunity to study the origin of MSPs and confirming the 'recycling' scenario, a theoretical model of MSP's origin. We develop an automated pipeline to monitor the system using Python programming language and Source-Extractor software for detecting the objects and measuring its magnitude. We obtain a series of observations with the 0.6m PROMPT-8 telescope at Cerro Tololo in Chile. The magnitude threshold for alert has been set 16.884 mag in R filter. When the magnitude of the system increases over the limit, 16.884 mag in filter R, the pipeline will alert us about the next possible switching of this system. The pipeline has been running on server at National Astronomical Research of Thailand (NARIT) since January 2018. We have found that, during January and February 2018, the system still remains in LMXB state.

We present follow-up photometry and spectroscopy of the rapidly pulsating subdwarf B star EC 22221-3152. Using the SAAO 1.0-m telescope and the 0.4-m Panchromatic Robotic Optical Monitoring and Polarimetry Telescopes (PROMPT) at the Cerro Tololo Inter-American Observatory (CTIO), we monitored the star photometrically for one week. By combining data from both telescopes, we were able to resolve 18 significant periodicities in the light curve. Seven of these signals consist of combination frequencies, a first harmonic, and possible rotational splittings that would be indicative of an 8.2-d rotation period. The remaining 11 periodicities appear to represent independent oscillation modes, including three not originally detected in the discovery work. Time series spectroscopy obtained with the Goodman spectrograph on the 4.1-m SOAR telescope reveals possible velocity variations corresponding to two of the observed pulsation modes. From atmospheric model fits to the spectra, we derive Teff = 35600\\pm 600$ K, log g = 5.86 ± 0.15, and log N(He)/N(H) = -1.4 ± 0.3 and confirm the star's status as one of the hottest sdBV r stars currently known.

We demonstrate how a small, robotically controlled telescope can be used to monitor bright, long-period variable stars in dense stellar systems like Galactic globular clusters. Observations of NGC 1851 gathered with the No. 5 PROMPT 0.4 m telescope in BVRI B V R I yielded quality color-magnitude diagrams to well below the horizontal branch at V = 16.1 mag V = 16.1     mag . We recovered many of the known RR Lyrae variables, clarified the nature of the three known bright variables in the cluster, detected two new long-period variables, and flagged seven more suspected variables. We describe methods that should yield good results in variable star searches and monitoring using this and other small telescopes.

Blazar OJ287 exhibits large thermal flares at least twice every 12 years. The times of these flares have been predicted successfully using the model of a quasi-Keplerian eccentric black hole binary where the secondary impacts the accretion disk of the primary, creating the thermal flares. New measurements of the historical light curve have been combined with the observations of the 2015 November/December flare to identify the impact record since year 1886, and to constrain the orbit of the binary. The orbital solution shows that the binary period, now 12.062 years, is decreasing at the rate of 36 days per century. This corresponds to an energy loss to gravitational waves that is 6.5 ± 4 % less than the rate predicted by the standard quadrupolar gravitational wave (GW) emission. We show that the difference is due to higher order gravitational radiation reaction terms that include the dominant order tail contributions.

Exercise and thiazolidinedione therapy normalize insulin action in the obese Zucker fatty rat. A L Hevener , D Reichart and J Olefsky Department of Medicine, University of California, San Diego 92093-0673, USA. Abstract Thiazolidinediones and exercise are both known to improve insulin action independently. Therefore, we determined whether combined therapy could normalize insulin action in the Zucker fatty (ZF) rat. Rats were fed troglitazone as a 0.2% food admixture over a 3-week exercise training period (treadmill running 5 days/week, 20 m/min, 0% grade, 60 min/day). Subsequent to drug and/or exercise therapy, animals were chronically cannulated in the carotid artery (sampling) and jugular vein (infusion). After a 4-day recovery from surgery, animals were exposed to a hyperinsulinemic (40 mU x kg(-1) x min(-1)) euglycemic clamp (8.5 +/- 0.12 mmol/l; P = 0.45 between groups). Independently, exercise (n = 7) and troglitazone (n = 7) improved the glucose disposal rate 20% (P = 0.04) and 76% (P = 0.001), respectively, when compared with untreated ZF controls (n = 11). In combination, exercise and troglitazone therapy (n = 6) produced significant increments in the following: tracer-determined glucose disposal rate (combined therapy, 52.4 +/- 2.9 mg x kg(-1) x min(-1), vs. untreated ZF, 25.8 +/- 0.8 mg x kg(-1) x min(-1); P = 0.0001), total GLUT4 protein (twofold increase; P = 0.001), insulin receptor substrate (IRS)-1 protein (fourfold increase; P = 0.0001), and Akt phosphorylation (2.9-fold increase; P = 0.002). In conclusion, 1) exercise and troglitazone therapy each improved insulin action in the ZF rat, whereas the combination of the two led to complete normalization of insulin sensitivity, and 2) combination treatment also resulted in normalization of GLUT4 total protein, IRS-1 protein, and Akt phosphorylation compared with lean littermates.

The involvement of PI3K, ERK and p38-dependent signaling system in the regulation of functional activity of erythroid precursors after blood loss (30% of circulating volume) was studied. We demonstrated the important role of PI3K and p38 in the suppression of differentiation of erythroid precursors the contribution of p38 to stimulation of mitotic activity of erythroid CFU, which maintains the growth potential of the precursors at the optimal physiological level. The classical MAPK/ERK-kinase pathway does not determine the proliferative and differentiation status of erythroid CFU.

We present spectroscopic and photometric observations of the emission-line star MWC 930 (V446 Sct) during its long-term optical brightening in 2006–2013. Based on our earlier data we suggested that the object has features found in Luminous Blue Variables (LBV), such as a high luminosity (~3 105 L⊙), a low wind terminal velocity (~140 km s−1), and a tendency to show strong brightness variations (~1 mag over 20 years). For the last ~7 years it has been exhibiting a continuous optical and near-IR brightening along with a change of the emission-line spectrum appearance and cooling of the star’s photosphere. We present the object’s V-band light curve, analyze the spectral variations, and compare the observed properties with those of other recognized Galactic LBVs, such as AG Car and HR Car. Overall we conclude the MWC 930 is a bona fide Galactic LBV that is currently in the middle of an S Dor cycle.

PPAR gamma is required for fat cell development and is the molecular target of antidiabetic thiazolidinediones (TZDs), which exert insulin-sensitizing effects in adipose tissue, skeletal muscle, and liver. Unexpectedly, we found that inactivation of PPAR gamma in macrophages results in the development of significant glucose intolerance plus skeletal muscle and hepatic insulin resistance in lean mice fed a normal diet. This phenotype was associated with increased expression of inflammatory markers and impaired insulin signaling in adipose tissue, muscle, and liver. PPAR gamma-deficient macrophages secreted elevated levels of factors that impair insulin responsiveness in muscle cells in a manner that was enhanced by exposure to FFAs. Consistent with this, the relative degree of insulin resistance became more severe in mice lacking macrophage PPAR gamma following high-fat feeding, and these mice were only partially responsive to TZD treatment. These findings reveal an essential role of PPAR gamma in macrophages for the maintenance of whole-body insulin action and in mediating the antidiabetic actions of TZDs.