We announce the discovery of two planets orbiting the M dwarfs GJ 251 (\(0.360\pm0.015\) M\(_\odot\)) and HD 238090 (\(0.578\pm0.021\) M\(_\odot\)) based on CARMENES radial velocity (RV) data. In ...addition, we independently confirm with CARMENES data the existence of Lalande 21185 b, a planet that has recently been discovered with the SOPHIE spectrograph. All three planets belong to the class of warm or temperate super-Earths and share similar properties. The orbital periods are 14.24 d, 13.67 d, and 12.95 d and the minimum masses are \(4.0\pm0.4\) \(M_\oplus\), \(6.9\pm0.9\) \(M_\oplus\), and \(2.7\pm0.3\) \(M_\oplus\) for GJ 251 b, HD 238090 b, and Lalande 21185 b, respectively. Based on the orbital and stellar properties, we estimate equilibrium temperatures of \(351.0\pm1.4\) K for GJ 251 b, \(469.6\pm2.6\) K for HD 238090 b, and \(370.1\pm6.8\) K for Lalande 21185 b. For the latter we resolve the daily aliases that were present in the SOPHIE data and that hindered an unambiguous determination of the orbital period. We find no significant signals in any of our spectral activity indicators at the planetary periods. The RV observations were accompanied by contemporaneous photometric observations. We derive stellar rotation periods of \(122.1\pm2.2\) d and \(96.7\pm3.7\) d for GJ 251 and HD 238090, respectively. The RV data of all three stars exhibit significant signals at the rotational period or its first harmonic. For GJ 251 and Lalande 21185, we also find long-period signals around 600 d, and 2900 d, respectively, which we tentatively attribute to long-term magnetic cycles. We apply a Bayesian approach to carefully model the Keplerian signals simultaneously with the stellar activity using Gaussian process regression models and extensively search for additional significant planetary signals hidden behind the stellar activity.
Incorporation of
14C-depleted (old) dissolved organic carbon (DOC) on/into particulate organic carbon (POC) has been suggested as a possible mechanism to explain the low Δ
14C-POC values observed in ...the deep ocean Druffel, E.R.M., Williams, P.M., 1990. Identification of a deep marine source of particulate organic carbon using bomb
14C. Nature, 347, 172–174.. A shipboard incubation experiment was performed in the Sargasso Sea to test this hypothesis. Finely ground dried plankton was incubated in seawater samples from the deep Sargasso Sea, both with and without a biological poison (HgCl
2). Changes in parameters such as biochemical composition and carbon isotopic signatures of bulk POC and its organic compound classes were examined to study the roles of sorptive processes and biotic activity on POC character. Following a 13-day incubation, the relative abundance of the acid-insoluble organic fraction increased. Abundances of extractable lipids and total hydrolyzable amino acids decreased for both treatments, but by a greater extent in the non-poisoned treatment. The Δ
14C values of POC recovered from the non-poisoned treatment were significantly lower than the value of the unaltered plankton material used for the incubation, indicating incorporation of
14C-depleted carbon, most likely DOC. The old carbon was present only in the lipid and acid-insoluble fractions. These results are consistent with previous findings of old carbon dominating the same organic fractions of sinking POC from the deep Northeast Pacific Hwang, J., Druffel, E.R.M., 2003. Lipid-like material as the source of the uncharacterized organic carbon in the ocean? Science, 299, 881–884.. However, the Δ
14C values of POC recovered from the poisoned treatment did not change as much as those from the non-poisoned treatment suggesting that biological processes were involved in the incorporation of DOC on/into POC.
Context. Variability caused by stellar activity represents a challenge to the discovery and characterization of terrestrial exoplanets and complicates the interpretation of atmospheric planetary ...signals. Aims. We aim to use a detailed modeling tool to reproduce the effect of active regions on radial velocity measurements, which aids the identification of the key parameters that have an impact on the induced variability. Methods. We analyzed the effect of stellar activity on radial velocities as a function of wavelength by simulating the impact of the properties of spots, shifts induced by convective motions, and rotation. We focused our modeling effort on the active star YZ CMi (GJ 285), which was photometrically and spectroscopically monitored with CARMENES and the Telescopi Joan Oró. Results. We demonstrate that radial velocity curves at different wavelengths yield determinations of key properties of active regions, including spot filling factor, temperature contrast, and location, thus solving the degeneracy between them. Most notably, our model is also sensitive to convective motions. Results indicate a reduced convective shift for M dwarfs when compared to solar-type stars (in agreement with theoretical extrapolations) and points to a small global convective redshift instead of blueshift. Conclusions. Using a novel approach based on simultaneous chromatic radial velocities and light curves, we can set strong constraints on stellar activity, including an elusive parameter such as the net convective motion effect.
The He I infrared (IR) line at a vacuum wavelength of 10833 A is a diagnostic for the investigation of atmospheres of stars and planets orbiting them. For the first time, we study the behavior of the ...He I IR line in a set of chromospheric models for M-dwarf stars, whose much denser chromospheres may favor collisions for the level population over photoionization and recombination, which are believed to be dominant in solar-type stars. For this purpose, we use published PHOENIX models for stars of spectral types M2 V and M3 V and also compute new series of models with different levels of activity following an ansatz developed for the case of the Sun. We perform a detailed analysis of the behavior of the He I IR line within these models. We evaluate the line in relation to other chromospheric lines and also the influence of the extreme ultraviolet (EUV) radiation field. The analysis of the He I IR line strengths as a function of the respective EUV radiation field strengths suggests that the mechanism of photoionization and recombination is necessary to form the line for inactive models, while collisions start to play a role in our most active models. Moreover, the published model set, which is optimized in the ranges of the Na I D2, H\(\alpha\), and the bluest Ca II IR triplet line, gives an adequate prediction of the He I IR line for most stars of the stellar sample. Because especially the most inactive stars with weak He I IR lines are fit worst by our models, it seems that our assumption of a 100% filling factor of a single inactive component no longer holds for these stars.
Corneal refractive surgery alters the biomechanical properties of the cornea.
This study was initiated to evaluate corneal biomechanical parameters after LASIK using a Corvis® ST tonometer (CST).
...This retrospective study included 51 eyes of 32 myopic patients. All CST measurements were performed 1 day before surgery and at the 1-month follow-up examination. The LASIK procedure included mechanical flap preparation using a Moria SBK microkeratome and an Allegretto excimer laser platform.
Statistically significant differences were observed for mean second applanation length, mean first and second deflection lengths, mean first and second deflection amplitudes, peak distance and radius of curvature. Statistically significant positive correlations were found between the change (Δ) in radius of curvature and Δ in manifest refraction spherical equivalent (MRSE), between the ablation depth and the Δ in intraocular pressure. Applying multiple regression models also revealed statistically significant differences in parameters obtained by CST measurements.
Several CST parameters were statistically significantly altered by LASIK thereby indicating that flap creation, ablation or both, significantly change the ability of the cornea to absorb or dissipate energy.
We have carried out a careful magnetic neutron scattering study of the heavy fermion compound URu sub(2)Si sub(2) to probe the possible existence of a small magnetic moment parallel to tetragonal ...basal plane in the 'hidden-order' phase. This small in-plane component of the magnetic moment on the uranium sites S sub(||) has been postulated by two recent models (rank-5 superspin/hastatic order) aiming to explain the hidden-order phase, in addition to the well-known out of-plane component S sub(perpendicular)approximate 0.01-0.04 mu sub(B)/U. In order to separate S sub(||) and S sub(perpendicular), we take advantage of the condition that for magnetic neutron scattering only the components of the magnetic structure that are perpendicular to the scattering vector Q contribute to the magnetic scattering. We find no evidence for an in-plane magnetic moment S sub(||). Based on the statistics of our measurement, we establish thatthe upper experimental limit forthe size of any possible in-plane component is (ProQuest: Formulae and/or non-USASCII text omitted)lt or = 1 x 10 super(-3) mu sub(b)/U.
The Cryogenic Dark Matter Search low ionization threshold experiment (CDMSlite) searches for interactions between dark matter particles and germanium nuclei in cryogenic detectors. The experiment has ...achieved a low energy threshold with improved sensitivity to low-mass (<10 GeV/c\(^2\)) dark matter particles. We present an analysis of the final CDMSlite data set, taken with a different detector than was used for the two previous CDMSlite data sets. This analysis includes a data "salting" method to protect against bias, improved noise discrimination, background modeling, and the use of profile likelihood methods to search for a dark matter signal in the presence of backgrounds. We achieve an energy threshold of 70 eV and significantly improve the sensitivity for dark matter particles with masses between 2.5 and 10 GeV/c\(^2\) compared to previous analyses. We set an upper limit on the dark matter-nucleon scattering cross section in germanium of 5.4\(\times\)10\(^{-42}\) cm\(^2\) at 5 GeV/c\(^2\), a factor of \(\sim\)2.5 improvement over the previous CDMSlite result.
Hypoxic respiratory failure in neonates born at or near term (at >34 weeks' gestation) may be caused by conditions such as primary persistent pulmonary hypertension, respiratory distress syndrome, ...aspiration of meconium, pneumonia or sepsis, and congenital diaphragmatic hernia.
1
,
2
Conventional therapy, short of extracorporeal membrane oxygenation, involves support with oxygen, mechanical ventilation, and the induction of alkalosis, neuromuscular blockade, and sedation.
3
–
6
None of these therapies have been found to reduce mortality or the need for extracorporeal membrane oxygenation. To date, selective pulmonary vasodilators free of systemic side effects have not been studied in large trials of neonates.
7
Nitric oxide, . . .
Kinesins are cytoskeletal motor proteins that share a common mechanochemical motor domain, and are responsible for trafficking macromolecules. Here we report the cloning and characterization of a ...monomeric, kinesin-3 (TKIN) from
Thermomyces lanuginosus. TKIN displayed a maximum rate of ATP hydrolysis at ∼55
°C; the
K
m
ATP
was also significantly greater at 50
°C. Gliding motility rates reached a maximum of 5.5
μm
s
−1 at 45
°C, which is among the highest rates reported for kinesin. Arrhenius energy barriers were calculated to be ∼103
kJ
mol
−1, nearly twofold greater than other mesophilic kinesin motors. The enthalpy of activation and entropy activation of TKIN were also significantly greater when compared to other mesophilic kinesins. A thermally induced aggregation of TKIN, which could be moderated by the addition of ATP, was observed at temperatures above 45
°C. Together, these results illustrate the kinetic response and stability of this unique motor protein at elevated temperatures.
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