Abstract
Based on analysis of high-precision photometry from the Transiting Exoplanet Survey Satellite combining with spectroscopy from the medium-resolution spectra of the Large Sky Area ...Multi-Object Fiber Spectroscopic Telescope, we investigated five double-lined spectroscopic eclipsing binaries (TIC 0165626871, TIC 0159105847, TIC 0122446076, TIC 0349294422, and TIC 0155968973). With the help of Wilson–Devinney program, we accurately derived their absolute stellar parameters. TIC 0165626871, TIC 0159105847, and TIC 0122446076 were identified as detached binaries, while TIC 0349294422 and TIC 0155968973 were recognized as A-subtype and W-subtype W UMa-type systems, respectively. Especially, absolute parameters of four binaries except for TIC 0122446076 were obtained for the first time. TIC 0165626871 also shows light variations of out-of-eclipse phases, which are probably contributed by starspots. The light pulsations of TIC 0122446076 could originate from the primary star that is located in the classical Cepheid instability strip. Evolutionary states of all stars were also discussed.
Frozen section examination could provide pathological diagnosis for surgery of thyroid nodules, which is time‐consuming, skill‐ and experience‐dependent. This study developed a rapid classification ...method for thyroid nodules and machine learning. Total 69 tissues were collected including 43 nodules and 26 nodule‐adjacent tissues. Intraoperative frozen section was first performed to give accurate diagnosis, and the rest frozen specimen were pretreated for probe electrospray ionization mass measurement. By multivariate analysis of mass scan data, a series compounds were found downregulated in the extraction solution of papillary thyroid carcinoma (PTC), but some were found upregulated by mass spectrometry imaging. m/z 758.5713 (PC34:2 + H+), m/z 772.5845 (PC32:0 + K+), and m/z 786.6037 (PC36:2 + H+) were firstly identified as potential biomarkers for nodular goiter (NG). Machine learning was employed by means of support vector machine (SVM) and random forest (RF) algorithms. For classification of PTC from NG, SVM and RF algorithms exhibited the same performance and the concordance was 94.2% and 94.4% between prediction and pathological diagnosis with positive and negative mass dataset, respectively. For the classification of PTC from PTC adjacent tissues, SVM was better than RF and the concordance was 93.8% and 83.3% with positive and negative mass dataset, respectively. With the identified compounds as training features, the sensitivity and specificity are 87.5% and 88.9% for the test set. The developed method could also correctly predict the malignancy of one medullary thyroid carcinoma and one adenomatous goiter (benign). The diagnosis time is about 10 min for one specimen, and it is very promising for the intraoperative diagnosis of papillary thyroid carcinoma.
A rapid classification method was developed for the malignant and benign thyroid nodules with ultrasound guided-fine needle aspiration biopsy (FNAB) samples. With probe electrospray ionization mass ...spectrometry, the mass-scan data of FNAB samples were used as datasets for machine learning. The patients were marked as malignant (98 patients), benign (110 patients) or undetermined (42 patients) by experienced doctors in terms of ultrasound, the B-Raf (BRAF) gene, and cytopathology inspections. Pairwise coupling was performed on 163 ions to generate 3630 ion ratios as new features for classifier training. With the new features, the performance of the multilayer perception (MLP) classifier is much better than that with the 163 ions as features directly. After training, the accuracy of the MLP classifier is as high as 92.0%. The accuracy of the single-blind test is 82.4%, which proved the good generalization ability of the MLP classifier. The overall concordance is 73.0% between prediction and six-month follow-up for patients in the undetermined group. Especially, the classifier showed high accuracy for the undetermined patients with suspicious for papillary carcinoma diagnosis (90.9%). In summary, the machine learning method based on FNAB samples has potential for real clinical applications.
With Rossi X-ray Timing Explorer (RXTE) data, we systematically study the cross-correlation and time lag in all spectral states of black hole X-ray binary (BHXB) XTE J1859+226 in detail during its ...entire 1999–2000 outburst that lasted for 166 days. Anti-correlations and positive correlations and their respective soft and hard X-ray lags are only detected in the first 100 days of the outburst when the luminosity is high. This suggests that the cross-correlations may be related to high luminosity. Positive correlations are detected in every state of XTE J1859+226, viz., hard state, hard-intermediate state (HIMS), soft-intermediate state (SIMS) and soft state. However, anti-correlations are only detected in HIMS and SIMS, anti-correlated hard lags are only detected in SIMS, while anti-correlated soft lags are detected in both HIMS and SIMS. Moreover, the ratio of the observations with anti-correlated soft lags to hard lags detected in XTE J1859+226 is significantly different from that in neutron star low-mass X-ray binaries (NS LMXBs). So far, anti-correlations are never detected in the soft state of BHXBs but detected in every branch or state of NS LMXBs. This may be due to the origin of soft seed photons in BHXBs is confined to the accretion disk and, for NS LMXBs, from both accretion disk and the surface of the NS. We notice that the timescale of anti-correlated time lags detected in XTE J1859+226 is similar with that of other BHXBs and NS LMXBs. We suggest that anti-correlated soft lag detected in BHXB may result from fluctuation in the accretion disk as well as NS LMXB.
Controlling the aromaticity in expanded porphyrins is a forefront research topic, and the strategy of using protonation-triggered conformational changes to fine-tune electronic properties and ...aromaticity has yet to be generalized in rigid and planar expanded porphyrins. Here, we synthesized phenanthrene-incorporated isoamethyrins that possess near-planar conformations and nonaromatic characters. However, when methanesulfonic acid (MSA) was added, geometric deformations occurred to minimize the unfavorable strain, resulting in macrocycles that were weakly aromatic as a whole.
All stellar-mass black holes have hitherto been identified by X-rays emitted from gas that is accreting onto the black hole from a companion star. These systems are all binaries with a black-hole ...mass that is less than 30 times that of the Sun
. Theory predicts, however, that X-ray-emitting systems form a minority of the total population of star-black-hole binaries
. When the black hole is not accreting gas, it can be found through radial-velocity measurements of the motion of the companion star. Here we report radial-velocity measurements taken over two years of the Galactic B-type star, LB-1. We find that the motion of the B star and an accompanying Hα emission line require the presence of a dark companion with a mass of Formula: see text solar masses, which can only be a black hole. The long orbital period of 78.9 days shows that this is a wide binary system. Gravitational-wave experiments have detected black holes of similar mass, but the formation of such massive ones in a high-metallicity environment would be extremely challenging within current stellar evolution theories.
We have investigated the relation between the root mean square (rms) variability and the X-ray flux (rms-flux relation) of the Z source Cyg X-2, and as well the energy dependence based on the Rossi ...X-ray Timing Explorer (
RXTE
) observations. We currently focus on the horizontal branch (HB), due to the negative correlation in flux of the soft and the hard X-rays. The rms-flux correlation has energy dependence as follows: positive at hard X-rays (above 10 keV) but negative at soft X-rays (below 10 keV). This provides a feature different from the previous one, and may be suggestive of different origins of X-rays below and above 10 keV. Nevertheless, the overall spectrum can be well fitted with a model consisting of a blackbody and Comptonization components, but the fitting results do not reveal any features around 10 keV that could account for such a change in the rms-flux relation.
In the radiation-hydrodynamics model, the time lag and fractional root-mean-squared (rms) amplitude as a function of emitted photon energy should show a minimum on the normal branch oscillations. ...This has been seen in the Z-sources Cyg X-2 and GX 5-1. Here, using the observations from the Rossi X-ray Timing Explorer (RXTE), we study the energy dependence of normal branch QPOs in the peculiar Z-source Cir X-1. We discuss the results in the context of radiation-hydrodynamics and the Comptonization model.
Based the Alfven wave oscillation model (AWOM) and relativistic precession model (RPM) for twin kHz QPOs, we estimate the emission positions of most detected kHz QPOs to be at
r
=18+/−3 km (
R
/15 ...km), except Cir X-1 at
r
∼30+/−5 km (
R
/15 km). For the proposed Keplerian frequency as an upper limit to kHz QPO, the spin effects in Kerr Spacetime are discussed, which have about a 5% (2%) modification for that of the Schwarzchild case for the spin frequency of 1000 (400) Hz. The application to the four typical QPO sources, Cir X-1, Sco X-1, SAX J1808.4-3658 and XTE 1807-294, is mentioned.
Cosmic Ray Removal in Fiber Spectroscopic Image Bai, Zhongrui; Zhang, Haotong; Yuan, Hailong ...
Publications of the Astronomical Society of the Pacific,
02/2017, Volume:
129, Issue:
972
Journal Article
Peer reviewed
Open access
Single-exposure spectra in large spectral surveys are valuable for time domain studies such as stellar variability, but there is no available method to eliminate cosmic rays for single-exposure, ...multi-fiber spectral images. In this paper, we describe a new method to detect and remove cosmic rays in multi-fiber spectroscopic single exposures. Through the use of two-dimensional profile fitting and a noise model that considers the position-dependent errors, we successfully detect as many as 80% of the cosmic rays and correct the cosmic ray polluted pixels to an average accuracy of 97.8%. Multiple tests and comparisons with both simulated data and real LAMOST data show that the method works properly in detection rate, false detection rate, and validity of cosmic ray correction.
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