1,183 research outputs found

    Geometry and Kinematics of a Dancing Milky Way: Unveiling the Precession and Inclination Variation across the Galactic Plane via Open Clusters

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    This Letter presents a study of the geometry and motion of the Galactic disk using open clusters in the Gaia era. The findings suggest that the inclination of the Galactic disk increases gradually from the inner to the outer disk, with a shift in orientation at the Galactocentric radius of approximately 5 to 7 kpc. Furthermore, this study brings forth the revelation that the mid-plane of the Milky Way may not possess a stationary or fixed position. A plausible explanation is that the inclined orbits of celestial bodies within our Galaxy exhibit a consistent pattern of elliptical shapes, deviating from perfect circularity; however, more observations are needed to confirm this. An analysis of the vertical motion along the Galactocentric radius reveals that the disk has warped with precession, and that the line-of-nodes shifts at different radii, aligning with the results from the classical Cepheids. Although there is uncertainty for precession/peculiar motion in Solar orbit, after considering the uncertainty, the study derives a median value of precession rate = 6.8 km/s/kpc in the Galaxy. This value for the derived precession in the outer disk is lower than those in the literature due to the systematic motion in Solar orbit (inclination angle = 0.6 deg). The study also finds that the inclinational variation of the disk is significant and can cause systematic motion, with the inclinational variation rate decreasing along the Galactic radius with a slope of -8.9 uas/yr/kpc. Moreover, the derived inclinational variation rate in Solar orbit is 59.1+-11.2(sample)+-7.7(VZsun) uas/yr, which makes it observable for high precision astrometry. The all-sky open cluster catalog based on Gaia DR3 and Galactic precession/inclinational variation fits as well as Python code related to these fits are available at https://nadc.china-vo.org/res/r101288/Comment: 9 pages, 6 figures. Accepted for publication in ApJL. See open cluster data and Python code at \url{https://nadc.china-vo.org/res/r101288/}. Comments/collaboration welcom

    Research Notes : China : Studies on genetic variation of soybean agronomic characters induced by seed irradiation

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    Since the 1950s, there have been a lot of geneticists who studied the genetic variation of the populations derived from irradiated seeds in the world, but only a few who studied the principle of selection for these populations. Some breeders have not only developed new varieties by using irradiation, but also have studied the genetic variation of irradiated popula-tions. However, the populations that they used had been often selected; therefore, it was hard to avoid that the results had been influenced by di-rectional selection effect

    Stable Isotopes of Clay Minerals from Autoclave Tests of Oil Sands: Implications for Clay Formation during Steaming of Alberta Clearwater Oil Sands

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    In an effort to evaluate mineral-water isotopic exchange during cyclic steam stimulation (CSS), solutions and\u3c2 μm berthierine-dominated solids from the Clearwater Formation oil sands of Alberta, Canada were analyzed for stable isotope compositions before and after reaction in autoclaves for 1008 h at 250 °C. There was no significant change in solution δ18O and δ2H, which is consistent with the high water/mineral ratio used in the experiments. The solids showed a marked decrease in both δ18O and δ2H following the experiments. Pre-run solids have δ18O of +9.5 to +12.9‰and δ2H of −114 to −113‰, whereas post-run solids have δ18O of −4.7 to +2.1‰ and δ2H of −147 to −128‰. Neither oxygen- nor hydrogen-isotope equilibrium was established between the solids and the solutions. Calculation suggests that oxygen-isotope exchange (44–58%) was greater between the solids and the solutions than was the case for hydrogen isotopes (23–50%). We propose that this behaviour resulted from partial inheritance of the pre-run berthierine structure during formation of the post-run smectite, chlorite-smectite and chlorite. This process confounds the use of clay mineral stable isotope compositions as a temperature indicator of in situ steam/steam condensate interaction with oil-sands reservoirs. The results also suggest an additional mechanism by which new clay minerals can be formed during CSS-related, artificial diagenesis

    Unveiling hidden stellar aggregates in the Milky Way: 1656 new star clusters found in Gaia EDR3

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    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

    Prognostic nomogram for bladder cancer with brain metastases: a National Cancer Database analysis.

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    BACKGROUND: This study aimed to establish and validate a nomogram for predicting brain metastasis in patients with bladder cancer (BCa) and assess various treatment modalities using a primary cohort comprising 234 patients with clinicopathologically-confirmed BCa from 2004 to 2015 in the National Cancer Database. METHODS: Machine learning method and Cox model were used for nomogram construction. For BCa patients with brain metastasis, surgery of the primary site, chemotherapy, radiation therapy, palliative care, brain confinement of metastatic sites, and the Charlson/Deyo Score were predictive features identified for building the nomogram. RESULTS: For the original 169 patients considered in the model, the areas under the receiver operating characteristic curve (AUC) were 0.823 (95% CI 0.758-0.889, P \u3c 0.001) and 0.854 (95% CI 0.785-0.924, P \u3c 0.001) for 0.5- and 1-year overall survival respectively. In the validation cohort, the nomogram displayed similar AUCs of 0.838 (95% CI 0.738-0.937, P \u3c 0.001) and 0.809 (95% CI 0.680-0.939, P \u3c 0.001), respectively. The high and low risk groups had median survivals of 1.91 and 5.09 months for the training cohort and 1.68 and 8.05 months for the validation set, respectively (both P \u3c 0.0001). CONCLUSIONS: Our prognostic nomogram provides a useful tool for overall survival prediction as well as assessing the risk and optimal treatment for BCa patients with brain metastasis

    Crystal structure of human nuclear pore complex component NUP43

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    AbstractNuclear pore complexes (NPC) form nuclear pores that cross the nuclear envelope and allow molecules to transport between the nucleus and the cytoplasm. We solved the crystal structure of human Nup43 (hNUP43), an important component in the Nup107 subcomplex of NPC. hNup43 adopts a seven-bladed β-propeller fold. We confirmed by ITC that neither human Nup37 (hNup37) nor human Nup133 (hNup133) interacts with hNup43. We demonstrated by analytical gel filtration that the human Nup85-Seh1L binary complex recruits hNup43 to form a ternary complex. Based on amino acid sequence analysis, we predicted the hNup85-hSeh1L binding surface of hNup43

    Metabolomics in retinal diseases: an update

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    Retinal diseases are a leading cause of visual loss and blindness, affecting a significant proportion of the population worldwide and having a detrimental impact on quality of life, with consequent economic burden. The retina is highly metabolically active, and a number of retinal diseases are associated with metabolic dysfunction. To better understand the pathogenesis underlying such retinopathies, new technology has been developed to elucidate the mechanism behind retinal diseases. Metabolomics is a relatively new “omics” technology, which has developed subsequent to genomics, transcriptomics, and proteomics. This new technology can provide qualitative and quantitative information about low-molecular-weight metabolites (M.W. < 1500 Da) in a given biological system, which shed light on the physiological or pathological state of a cell or tissue sample at a particular time point. In this article we provide an extensive review of the application of metabolomics to retinal diseases, with focus on age-related macular degeneration (AMD), diabetic retinopathy (DR), retinopathy of prematurity (ROP), glaucoma, and retinitis pigmentosa (RP)
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