Context. The space mission Kepler provides us with long and uninterrupted photometric time series of red giants. We are now able to probe the rotational behaviour in their deep interiors using the ...observations of mixed modes. Aims. We aim to measure the rotational splittings in red giants and to derive scaling relations for rotation related to seismic and fundamental stellar parameters. Methods. We have developed a dedicated method for automated measurements of the rotational splittings in a large number of red giants. Ensemble asteroseismology, namely the examination of a large number of red giants at different stages of their evolution, allows us to derive global information on stellar evolution. Results. We have measured rotational splittings in a sample of about 300 red giants. We have also shown that these splittings are dominated by the core rotation. Under the assumption that a linear analysis can provide the rotational splitting, we observe a small increase of the core rotation of stars ascending the red giant branch. Alternatively, an important slow down is observed for red-clump stars compared to the red giant branch. We also show that, at fixed stellar radius, the specific angular momentum increases with increasing stellar mass. Conclusions. Ensemble asteroseismology indicates what has been indirectly suspected for a while: our interpretation of the observed rotational splittings leads to the conclusion that the mean core rotation significantly slows down during the red giant phase. The slow-down occurs in the last stages of the red giant branch. This spinning down explains, for instance, the long rotation periods measured in white dwarfs.
The first public release of long-cadence stellar photometric data collected by the NASA Kepler mission has now been made available. In this paper, we characterize the red giant (G-K) stars in this ...large sample in terms of their solar-like oscillations. We use published methods and well-known scaling relations in the analysis. Just over 70 per cent of the red giants in the sample show detectable solar-like oscillations, and from these oscillations we are able to estimate the fundamental properties of the stars. This asteroseismic analysis reveals different populations: low-luminosity H-shell burning red giant branch stars, cool high-luminosity red giants on the red giant branch and He-core burning clump and secondary-clump giants.
Abstract
We have employed state-of-the-art cross-correlation noise spectroscopy (CCNS) to study carrier dynamics in silicon heterojunction solar cells (SHJ SCs). These cells were composed of a light ...absorbing
n
-doped monocrystalline silicon wafer contacted by passivating layers of
i
-
a
-Si:H and doped
a
-Si:H selective contact layers. Using CCNS, we are able to resolve and characterize four separate noise contributions: (1) shot noise with Fano factor close to unity due to holes tunneling through the np-junction, (2) a 1/
f
term connected to local potential fluctuations of charges trapped in a-Si:H defects, (3) generation-recombination noise with a time constant between 30 and 50 μs and attributed to recombination of holes at the interface between the ITO and
n-a
-Si:H window layer, and (4) a low-frequency generation-recombination term observed below 100 K which we assign to thermal emission over the ITO/
ni
-
a
-Si:H interface barrier. These results not only indicate that CCNS is capable of reveling otherwise undetectable relaxation process in SHJ SCs and other multi-layer devices, but also that the technique has a spatial selectivity allowing for the identification of the layer or interface where these processes are taking place.
Tissue verification of noncaseating granulomas is recommended for the diagnosis of sarcoidosis. Bronchoscopy with transbronchial lung biopsies, the current diagnostic standard, has moderate ...sensitivity in assessing granulomas. Endosonography with intrathoracic nodal aspiration appears to be a promising diagnostic technique.
To evaluate the diagnostic yield of bronchoscopy vs endosonography in the diagnosis of stage I/II sarcoidosis.
Randomized clinical multicenter trial (14 centers in 6 countries) between March 2009 and November 2011 of 304 consecutive patients with suspected pulmonary sarcoidosis (stage I/II) in whom tissue confirmation of noncaseating granulomas was indicated.
Either bronchoscopy with transbronchial and endobronchial lung biopsies or endosonography (esophageal or endobronchial ultrasonography) with aspiration of intrathoracic lymph nodes. All patients also underwent bronchoalveolar lavage.
The primary outcome was the diagnostic yield for detecting noncaseating granulomas in patients with a final diagnosis of sarcoidosis. The diagnosis was based on final clinical judgment by the treating physician, according to all available information (including findings from initial bronchoscopy or endosonography). Secondary outcomes were the complication rate in both groups and sensitivity and specificity of bronchoalveolar lavage in the diagnosis of sarcoidosis.
A total of 149 patients were randomized to bronchoscopy and 155 to endosonography. Significantly more granulomas were detected at endosonography vs bronchoscopy (114 vs 72 patients; 74% vs 48%; P < .001). Diagnostic yield to detect granulomas for endosonography was 80% (95% CI, 73%-86%); for bronchoscopy, 53% (95% CI, 45%-61%) (P < .001). Two serious adverse events occurred in the bronchoscopy group and 1 in the endosonography group; all patients recovered completely. Sensitivity of the bronchoalveolar lavage for sarcoidosis based on CD4/CD8 ratio was 54% (95% CI, 46%-62%) for flow cytometry and 24% (95% CI, 16%-34%) for cytospin analysis.
Among patients with suspected stage I/II pulmonary sarcoidosis undergoing tissue confirmation, the use of endosonographic nodal aspiration compared with bronchoscopic biopsy resulted in greater diagnostic yield.
clinicaltrials.gov Identifier: NCT00872612.
In addition to its search for extrasolar planets, the NASA Kepler mission provides exquisite data on stellar oscillations. We report the detections of oscillations in 500 solar-type stars in the ...Kepler field of view, an ensemble that is large enough to allow statistical studies of intrinsic stellar properties (such as mass, radius, and age) and to test theories of stellar evolution. We find that the distribution of observed masses of these stars shows intriguing differences to predictions from models of synthetic stellar populations in the Galaxy.
Abstract
BACKGROUND
Radiosurgery is the main alternative to microsurgical resection for benign meningiomas.
OBJECTIVE
To assess the long-term efficacy and safety of radiosurgery for meningiomas with ...respect to tumor growth and prevention of associated neurological deterioration. Medium- to long-term outcomes have been widely reported, but no large multicenter series with long-term follow-up have been published.
METHODS
From 15 participating centers, we performed a retrospective observational analysis of 4565 consecutive patients harboring 5300 benign meningiomas. All were treated with Gamma Knife radiosurgery at least 5 years before assessment for this study. Clinical and imaging data were retrieved from each center and uniformly entered into a database by 1 author (A.S.).
RESULTS
Median tumor volume was 4.8 cm3, and median dose to tumor margin was 14 Gy. All tumors with imaging follow-up > 24 months were excluded. Detailed results from 3768 meningiomas (71%) were analyzed. Median imaging follow-up was 63 months. The volume of treated tumors decreased in 2187 lesions (58%), remained unchanged in 1300 lesions (34.5%), and increased in 281 lesions (7.5%), giving a control rate of 92.5%. Only 84 (2.2%) enlarging tumors required further treatment. Five- and 10-year progression-free survival rates were 95.2% and 88.6%, respectively. Tumor control was higher for imaging defined tumors vs grade I meningiomas (P > .001), for female vs male patients (P > .001), for sporadic vs multiple meningiomas (P > .001), and for skull base vs convexity tumors (P > .001). Permanent morbidity rate was 6.6% at the last follow-up.
CONCLUSION
Radiosurgery is a safe and effective method for treating benign meningiomas even in the medium to long term.
Kepler observations of the beaming binary KPD 1946+4340 Bloemen, S.; Marsh, T. R.; Østensen, R. H. ...
Monthly Notices of the Royal Astronomical Society,
January 2011, Letnik:
410, Številka:
3
Journal Article, Web Resource
Recenzirano
Odprti dostop
The Kepler Mission has acquired 33.5 d of continuous 1-min photometry of KPD 1946+4340, a short-period binary system that consists of a subdwarf B star (sdB) and a white dwarf. In the light curve, ...eclipses are clearly seen, with the deepest occurring when the compact white dwarf crosses the disc of the sdB (0.4 per cent) and the more shallow ones (0.1 per cent) when the sdB eclipses the white dwarf. As expected, the sdB is deformed by the gravitational field of the white dwarf, which produces an ellipsoidal modulation of the light curve. Spectacularly, a very strong Doppler beaming (also known as Doppler boosting) effect is also clearly evident at the 0.1 per cent level. This originates from the sdB's orbital velocity, which we measure to be 164.0 ± 1.9 km s−1 from supporting spectroscopy. We present light-curve models that account for all these effects, as well as gravitational lensing, which decreases the apparent radius of the white dwarf by about 6 per cent, when it eclipses the sdB. We derive system parameters and uncertainties from the light curve using Markov chain Monte Carlo simulations. Adopting a theoretical white dwarf mass-radius relation, the mass of the subdwarf is found to be 0.47 ± 0.03 M⊙ and the mass of the white dwarf 0.59 ± 0.02 M⊙. The effective temperature of the white dwarf is 15 900 ± 300 K. With a spectroscopic effective temperature of T
eff= 34 730 ± 250 K and a surface gravity of log g= 5.43 ± 0.04, the subdwarf has most likely exhausted its core helium, and is in a shell He burning stage.
The detection of Doppler beaming in Kepler light curves potentially allows one to measure radial velocities without the need of spectroscopic data. For the first time, a photometrically observed Doppler beaming amplitude is compared to a spectroscopically established value. The sdB's radial velocity amplitude derived from the photometry (168 ± 4 km s−1) is in perfect agreement with the spectroscopic value. After subtracting our best model for the orbital effects, we searched the residuals for stellar oscillations but did not find any significant pulsation frequencies.
The mechanisms by which microRNA dysfunction contributes to the pathogenesis of diffuse large B cell lymphoma (DLBCL) are not well established. The identification of the genes and pathways directly ...targeted by these small regulatory RNAs is a critical step to advance this field. Using unbiased genome-wide approaches in DLBCL, we discovered that the oncogenic microRNA-155 (miR-155) directly targets the bone morphogenetic protein (BMP)-responsive transcriptional factor SMAD5. Surprisingly, we found that in DLBCL a noncanonical signaling module linking TGF-β1 signals to SMAD5 is also active. In agreement with these data, miR-155 overexpression rendered DLBCLs resistant to the growth-inhibitory effects of both TGF-β1 and BMPs, via defective induction of p21 and impaired cell cycle arrest. In confirmatory experiments, RNAi-based SMAD5 knockdown recapitulated in vitro and in vivo the effects miR-155 overexpression. Furthermore, in primary DLBCLs, miR-155 overexpression inhibited SMAD5 expression and disrupted its activity, as defined by individual and global analyses of its transcriptional targets. Together, our data helped explain miR-155 function, highlighted a hitherto unappreciated role of SMAD5 in lymphoma biology, and defined a unique mechanism used by cancer cells to escape TGF-β's growth-inhibitory effects.
The geologic context of red organic‐rich materials (ROR) found across an elongated 200 km region on Ceres is evaluated with spectral information from the multispectral framing camera (FC) and the ...visible and near‐infrared mapping spectrometer (VIR) of Dawn. Discrete areas of ROR materials are found to be associated with small fresh craters less than a few hundred meters in diameter. Regions with the highest concentration of discrete ROR areas exhibit a weaker diffuse background of ROR materials. The observed pattern could be consistent with a field of secondary impacts, but no appropriate primary crater has been found. Both endogenic and exogenic sources are being considered for these distinctive organic materials.
Traditional surgical procedures for intractable idiopathic constipation are associated with a variable outcome and substantial morbidity. The symptomatic response, physiological effect and effect on ...quality of life of sacral nerve stimulation (SNS) were evaluated in patients with constipation (slow transit and normal transit with impaired evacuation).
In a prospective study at five European sites patients who failed conservative treatment underwent 21 days test stimulation. Patients with >50% improvement in symptoms underwent permanent neurostimulator implantation. Primary end points were increased defecation frequency, decreased straining and decreased sensation of incomplete evacuation.
62 patients (55 female, median age 40 years) underwent test stimulation, of whom 45 (73%) proceeded to chronic stimulation. 39 (87%) of these 45 patients achieved treatment success. After a median 28 (range 1-55) months follow-up, defecation frequency increased from 2.3 to 6.6 evacuations per week (p<0.001). Days per week with evacuation increased from 2.3 to 4.8 (p<0.001). There was a decrease in time spent toileting (10.5 to 5.7 min, p=0.001), straining (75-46% of successful evacuations, p<0.001), perception of incomplete evacuation (71.5-46% of successful evacuations, p<0.001) and subjective rating of abdominal pain and bloating (p<0.001). Cleveland Clinic constipation score (0=no to 30=severe constipation) decreased from 18 to 10 (p<0.001). Visual analogue scale (VAS) score (0=severe to 100=no symptoms) increased from 8 to 66 (p<0.001). Patients with slow and normal transit benefited. Quality of life significantly improved. Colonic transit normalised in half of those with baseline slow transit (p=0.014).
SNS is effective in the treatment of idiopathic slow and normal transit constipation resistant to conservative treatment. Clinical Trial Number NCT00200005.
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