87 research outputs found
Unveiling hidden stellar aggregates in the Milky Way: 1656 new star clusters found in Gaia EDR3
We report 1,656 new star clusters found in the Galactic disk (|b|<20 degrees)
beyond 1.2 kpc, using Gaia EDR3 data. Based on an unsupervised machine learning
algorithm, DBSCAN, and followed our previous studies, we utilized a unique
method to do the data preparation and obtained the clustering coefficients,
which proved to be an effective way to search blindly for star clusters. We
tabulated the physical parameters and member stars of the new clusters, and
presented some interesting examples, including a globular cluster candidate.
The cluster parameters and member stars are available at CDS via anonymous ftp
to https://cdsarc.cds.unistra.fr/ftp/vizier.submit//he22c. We examined the new
discoveries and discussed their statistical properties. The proper motion
dispersions and radii of the new clusters were the same as the previously
reported ones. The new star clusters beyond 1.2 kpc were older than those in
the solar neighborhood, and the new objects found in the third Galactic
quadrant presented the lowest line-of-sight extinctions. Combined with our
previous results, the total population of new clusters detected through our
method was 2,541, corresponding to 55% of all newly published clusters in the
Gaia era. The number of cataloged Gaia star clusters was also increased to
nearly six thousand. In the near future, it is necessary to make a unified
confirmation and member star determination for all reported clusters.Comment: 16 pages, 11 figures, 3 tables with full clusters/members data link
in CDS, accepted for publication in ApJ
Improved drought resistance by intergeneric graftingin Salicaceae plants under water deficits
In this study, intergeneric grafting was employed between Populus cathayana and Salix rehderiana to investigate the grafting compatibility of the two Salicaceae plants and to reveal whether grafting can improve their drought resistance. Under different grafting combinations (P. cathayana scion with P. cathayana rootstock, P/P; P. cathayana scion with S. rehderiana rootstock, P/S; S. rehderiana scion with S. rehderiana rootstock, S/S; and S. rehderiana scion with P. cathayana rootstock, S/P), the survival and growth rate, biomass accumulation and allocation, photosynthetic traits, carbon isotope composition (delta C-13), relative water content (RWC) and nonstructural carbohydrates (NSCs) were measured. The results showed that the grafting compatibility between P. cathayana and S. rehderiana was very high, as the survival rates ranged from 76% to 100% under different grafting combinations. Drought significantly decreased growth, biomass accumulation, photosynthetic pigment contents, net photosynthesis rates (P) and RWC, and increased delta C-13 in all grafting combinations. Under drought stress, biomass accumulation, total chlorophyll, transpiration rate (E) and P-n were higher in P/P and P/S than in S/S and S/P. Compared with P/P, the growth rate, biomass accumulation, root/aboveground ratio (R/A ratio), carotenoid, RWC, starch and total soluble sugar (TSS) of P/S were less affected by drought. The height growth rate (GRH), R/A ratio, carotenoid, chlorophyll a, total chlorophyll, WUEi and TSS of S/P were lower than those of S/S under water-limited conditions. Moreover, a principal component analysis indicated that P/S and S/S had higher drought resistance than P/P and S/P under water deficits. The used method allows combining specific advantageous traits from P. cathayana and S. rehderiana, which may be a highly useful tool to enhance drought resistance in the cultivation of Salicaceae plants.Peer reviewe
Nonlinear dynamic analysis on maglev train system with flexible guideway and double time-delay feedback control
In this paper, the dynamic behavior of time-delayed feedback control for maglev train system with double discrete time delays is considered with flexible guideway. Considering the maglev guideway as Beroulli-Euler beam, the mathematical model of maglev system with flexible guideway is constructed. The time delay of the two state feedback signals in the maglev system occurs simultaneously, and the values are different. The present treatment method only considers one single feedback delay, which are insufficiency. Thus, the Hopf bifurcation with double time-delay feedback of maglev train running on the flexible guideway is analyzed considering time-delayed position feedback signal Ï„1 and velocity feedback signal Ï„2. A novel method is presented to develop the double-parametric Hopf bifurcation diagram in relation to Ï„1 and Ï„2. Sufficient numerical simulations are provided to illustrate the complex dynamical behavior of the discrete delays Ï„1 and Ï„2 for maglev system and we verify the obtained theoretical analysis. Finally, the field experiments are carried out to validate the effectiveness of the Hopf bifurcation analytical method preliminarily
Short-term outcomes of robot-assisted versus video-assisted thoracoscopic surgery for non-small cell lung cancer patients with neoadjuvant immunochemotherapy: a single-center retrospective study
BackgroundNeoadjuvant immunochemotherapy has been increasingly applied to treat non-small cell lung cancer (NSCLC). However, the comparison between robotic-assisted thoracoscopic surgery (RATS) and video-assisted thoracoscopic surgery (VATS) in the feasibility and oncological efficacy following neoadjuvant immunochemotherapy is scarce. This study aims to assess the superiorities of RATS over (VATS) concerning short-term outcomes in treating NSCLC patients with neoadjuvant immunochemotherapy.MethodsNSCLC patients receiving RATS or VATS lobectomy following neoadjuvant immunochemotherapy at Shanghai Chest Hospital from 2019 to 2022 were retrospectively identified. Baseline clinical characteristics, perioperative outcomes, and survival profiles were analyzed.ResultsForty-six NSCLC patients with neoadjuvant immunochemotherapy were included and divided into the RATS (n=15) and VATS (n=31) groups. The baseline clinical characteristics and induction-related adverse events were comparable between the two groups (all p>0.050). The 30-day mortality in the RATS and VATS groups were 0% and 3.23%, respectively (p=1.000). Patients undergoing RATS were associated with reduced surgical-related intensive unit care (ICU) stay than those receiving VATS (0.0 [0.0-0.0] vs. 0.0 [0.0-1.0] days, p=0.026). Moreover, RATS assessed more N1 LNs (6.27 ± 1.94 vs 4.90 ± 1.92, p=0.042) and LN stations (3.07 ± 1.03 vs 2.52 ± 0.57, p=0.038) compared with VATS. By comparison, no difference was found in surgical outcomes, pathological results, and postoperative complications between the RATS and VATS groups (all p>0.050). Finally, RATS and VATS achieved comparable one-year recurrence-free survival (82.96% vs. 85.23%, p=0.821) and the timing of central nervous system, LN, and bone recurrences (all p>0.050).ConclusionRATS is safe and feasible for NSCLC patients with neoadjuvant immunochemotherapy, reducing surgical-related ICU stay, assessing increased N1 LNs and stations, and achieving similar survival profiles to VATS
Reflection on the Biological Significance of Minimally Invasive Surgery for Lung Cancer
Minimal invasive surgery with short operation time and enhanced recovery after surgery can truly achieve biological minimal invasiveness. The minimal invasive lung cancer surgery includes several kinds, such as uni-portal video-assisted thoracoscopic surgery (VATS) and multi-portal VATS. Robotic-assisted thoracic surgery (RATS) can be categorized into multi-portal VATS. As a frontier technology of minimal invasive surgical technique, surgical robotic system has been broadly applied in many areas. The average RATS operation time is (91.51±30.80) min among our team, which is much shorter than reported uni-portal VATS operation time. For now, RATS has some drawbacks and is lacking of national practice guidelines, which, we believe, will be solved by technology development and large-scale randomized controlled trials
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