A Catalog of Cool Dwarf Targets for the Transiting Exoplanet Survey Satellite

We present a catalog of cool dwarf targets ($V-J>2.7$, $T_{\rm eff} \lesssim 4000 K$) and their stellar properties for the upcoming Transiting Exoplanet Survey Satellite (TESS), for the purpose of determining which cool dwarfs should be observed using two-minute observations. TESS has the opportunity to search tens of thousands of nearby, cool, late K and M-type dwarfs for transiting exoplanets, an order of magnitude more than current or previous transiting exoplanet surveys, such as {\it Kepler}, K2 and ground-based programs. This necessitates a new approach to choosing cool dwarf targets. Cool dwarfs were chosen by collating parallax and proper motion catalogs from the literature and subjecting them to a variety of selection criteria. We calculate stellar parameters and TESS magnitudes using the best possible relations from the literature while maintaining uniformity of methods for the sake of reproducibility. We estimate the expected planet yield from TESS observations using statistical results from the Kepler Mission, and use these results to choose the best targets for two-minute observations, optimizing for small planets for which masses can conceivably be measured using follow up Doppler spectroscopy by current and future Doppler spectrometers. The catalog is incorporated into the TESS Input Catalog and TESS Candidate Target List until a more complete and accurate cool dwarf catalog identified by ESA's Gaia Mission can be incorporated.Comment: Accepted to The Astronomical Journal. For the full catalog, please contact the corresponding autho

Device closure of post-myocardial infarction ventricular septal defect three weeks after coronary angioplasty

Percutaneus device closure appears to be safe and effective in patients treated for a residual shunt after initial surgical closure, as well as after two to three weeks of index myocardial infarction. The index case presented with a ventricular septal defect on second of acute myocardial infarction thrombolysed with streptokinase. The general condition of the patient was fairly stable. Cardiac catheterization and coronary angiography showed significant left to right shunt and there was 90 % proximal stenosis of left anterior descending coronary artery. Other coronary arteries were normal. Angioplasty and stenting to the coronary artery lesion was done using drug eluting stent (DES) with very good angiographic result. Patient was discharged after four days in stable condtion. After 3 weeks his ventricular septal defect was closed percutaneusly using cardio -O-fix device with tiny residual shunt. The procedure was uneventful and of brief duration. He was discharged after 5 days of the post procedure in very stable condition with minimal residual shunt. A staged procedure is a better option if the condition of the patient allows strengthening ventricular septal defect border

On the Nature of Star Formation at Large Galactic Radii

We have compared far-ultraviolet (FUV), near-ultraviolet (NUV), and Halpha measurements for star forming regions in 21 galaxies, in order to characterise the properties of their discs at radii beyond the main optical radius (R25). In our representative sample of extended and non-extended UV discs we find that half of the extended UV discs also exhibit extended Halpha emission. We find that extended UV discs fall into two categories, those with a sharp truncation in the Halpha disc close to the optical edge (R25), and those with extended emission in Halpha as well as in the ultraviolet. Although most galaxies with strong Halpha truncations near R25 show a significant corresponding falloff in UV emission (factor 10--100), the transition tends to be much smoother than in Halpha, and significant UV emission often extends well beyond this radius, confirming earlier results by Thilker et al. (2007) and others. After correcting for dust attenuation the median fraction of total FUV emission from regions outside of R25 is 1.7%, but it can be as high as 35% in the most extreme cases. The corresponding fractions of Halpha emission are approximately half as large on average. This difference reflects both a slightly lower ratio of Halpha to UV emission in the HII regions in the outer discs, as well as a lower fraction of star clusters showing HII regions. Most HII regions in the extended disc have fluxes consistent with small numbers of ionising O-type stars, and this poor sampling of the upper initial mass function in small clusters can probably account for the differences in the emission properties, consistent with earlier conclusions by Zaritsky & Christlein (2007), without needing to invoke a significant change in the stellar IMF itself. Consistent Ha/FUV ratios and brightest HII region to total Halpha fluxes in the inner and extended discs across our whole galaxy sample demonstrate no evidence for a change in the cluster luminosity function or the IMF in the low gas density outer disc.Comment: Accepted for publication in MNRAS. 21 Pages, 13 Figures, 2 Table

Beneficial effects of melatonin on stroke-induced muscle atrophy in focal cerebral ischemic rats

Muscle atrophy is the result of two opposing conditions that can be found in pathological or diseased muscles: an imbalance in protein synthesis and degradation mechanisms. Thus, we investigated whether exogenous melatonin could regulate muscle components in stroke-induced muscle atrophy in rats. Comparing muscle phenotypes, we found that long-term melatonin administration could influence muscle mass. Muscle atrophy-related genes, including muscle atrophy F-box (MAFbx) and muscle ring finger 1 (MuRF1) were significantly down-regulated in melatonin-administered rats in the gastrocnemius. However, only MAFbx at the mRNA level was attenuated in the soleus of melatonin-administered rats. Insulin-like growth factor-1 receptor (IGF-1R) was significantly over-expressed in melatonin-administered rats in both the gastrocnemius and soleus muscles. Comparing myosin heavy chain (MHC) components, in the gastrocnemius, expression of both slow- and fast-type isoforms were significantly enhanced in melatonin-administered rats. These results suggest that long-term exogenous melatonin-administration may have a prophylactic effect on muscle atrophy through the MuRF1/MAFbx signaling pathway, as well as a potential therapeutic effect on muscle atrophy through the IGF-1-mediated hypertrophic signaling pathway in a stroke animal model

The AGB population of NGC 6822: distribution and the C/M ratio from JHK photometry

NGC 6822 is an irregular dwarf galaxy and part of the Local Group. Its close proximity and apparent isolation provide a unique opportunity to study galactic evolution without any obvious strong external influences. This paper aims to study the spatial distribution of the asymptotic giant branch (AGB) population and metallicity in NGC 6822. Using deep, high quality JHK photometry, taken with WFCAM on UKIRT, carbon- and oxygen-rich AGB stars have been isolated. The ratio between their number, the C/M ratio, has then been used to derive the [Fe/H] abundance across the galaxy. The tip of the red giant branch is located at K0 = 17.41 \pm 0.11 mag and the colour separation between carbon- and oxygen-rich AGB stars is at (J - K)0 = 1.20 \pm 0.03 mag (i.e. (J - K)2MAS S {\guillemotright} 1.28 mag). A C/M ratio of 0.62 \pm 0.03 has been derived in the inner 4 kpc of the galaxy, which translates into an iron abundance of [Fe/H] = -1.29\pm0.07 dex. Variations of these parameters were investigated as a function of distance from the galaxy centre and azimuthal angle. The AGB population of NGC 6822 has been detected out to a radius of 4 kpc giving a diameter of 56 arcmin. It is metal-poor, but there is no obvious gradient in metallicity with either radial distance from the centre or azimuthal angle. The detected spread in the TRGB magnitude is consistent with that of a galaxy surrounded by a halo of old stars. The C/M ratio has the potential to be a very useful tool for the determination of metallicity in resolved galaxies but a better calibration of the C/M vs. [Fe/H] relation and a better understanding of the sensitivities of the C/M ratio to stellar selection criteria is first required

Atmospheric neutrino flux supported by recent muon experiments

We present a new one-dimensional calculation of low and intermediate energy atmospheric muon and neutrino fluxes, using up-to-date data on primary cosmic rays and hadronic interactions. We study several sources of uncertainties relevant to our calculations. A comparison with the muon fluxes and charge ratios measured in several modern balloon-borne experiments suggests that the atmospheric neutrino flux is essentially lower than one used for the standard analyses of the sub-GeV and multi-GeV neutrino induced events in underground detectors.Comment: 23 pages, 7 figures, 2 tables. Typos corrected, figure layout improved, references added. Final version accepted for publication in PL

Implications of a non-universal IMF from C, N, and O abundances in very metal-poor Galactic stars and damped Lyman-alpha absorbers

Recently revealed C, N, and O abundances in the most metal-poor damped Lyman-alpha (DLA) absorbers are compared with those of extremely metal-poor stars in the Galactic halo, as well as extragalactic H II regions, to decipher nucleosynthesis and chemical enrichment in the early Universe. These comparisons surprisingly identify a relatively high C/O ratio and a low N/O ratio in DLA systems, which is hard to explain theoretically. We propose that if these features are confirmed by future studies, this effect occurs because the initial mass function in metal-poor DLA systems has a cut-off at the upper mass end at around 20-25 Msun, thus lacks the massive stars that provide the nucleosynthesis products leading to the low C/O and high N/O ratios. This finding is a reasonable explanation of the nature of DLA systems in which a sufficient amount of cold H I gas remains intact because of the suppression of ionization by massive stars. In addition, our claim strongly supports a high production rate of N in very massive stars, which might be acceptable in light of the recent nucleosynthesis calculations with fast rotation models. The updates of both abundance data and nucleosynthesis results will strengthen our novel proposition that the C/O and N/O abundances are a powerful tool for inferring the form of the initial mass function.Comment: 9 pages including 5 figures, accepted for publication in A&

The stellar content of the Hamburg/ESO survey VI. The metallicity distribution of main-sequence turnoff stars in the Galactic halo

We determine the metallicity distribution function (MDF) of the Galactic halo based on metal-poor main-sequence turnoff-stars (MSTO) which were selected from the Hamburg/ESO objective-prism survey (HES) database. Corresponding follow-up moderateresolution observations (R ~ 2000) of some 682 stars (among which 617 were accepted program stars) were carried out with the 2.3m telescope at the Siding Spring Observatory (SSO). Corrections for the survey volume covered by the sample stars were quantitatively estimated and applied to the observed MDF. The corrections are quite small, when compared with those for a previously studied sample of metal-poor giants. The corrected observational MDF of the turnoff sample was then compared with that of the giants, as well as with a number of theoretical predictions of Galactic chemical evolution, including the mass-loss modified Simple Model. Although the survey-volume corrected MDFs of the metal-poor turnoff and the halo giants notably differ in the region of [Fe/H] > -2.0, below [Fe/H] ~ -2.0, (the region we scientifically focus on most) both MDFs show a sharp drop at [Fe/H] ~ -3.6 and present rather similar distributions in the low-metallicity tail. Theoretical models can fit some parts of the observed MDF, but none is found to simultaneously reproduce the peak as well as the features in the metal-poor region with [Fe/H] between -2.0 to -3.6. Among the tested models only the GAMETE model, when normalized to the tail of the observed MDF below [Fe/H] ~ -3.0, and with Z_{cr} = 10^{-3.4}Z_{\odot}, is able to predict the sharp drop at [Fe/H] ~ -3.6.Comment: 10 pages, 11 figures, accepted for publication in A&