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Persicaria subterranea Bo Li, a new species from Xizang in southwestern China, is described and illustrated in this study. Gross morphology and pollen micromorphology corroborate its placement within Persicaria sect. Cephalophilon. Unique to this section, P. subterranea is the only species known to exhibit subterranean cleistogamous flowers, making it distinct within the sect. Cephalophilon. Morphologically, it shows the closest resemblance to P. glacialis (Meisn.) H. Hara and its variety, P. glacialis var. przewalskii (A.K. Skvortsov & Borodina) M.J. Kong & S.P. Hong. However, it could be readily distinguished from these related taxa by leaf shapes and indumentum, inflorescence structure, number of stamens, and achene morphology. In addition, we provide diagnostic characteristics, a detailed morphological description, line drawing, and information on the distribution and habitat for this new species, as along with comparable photographs of the three related taxa. [ABSTRACT FROM AUTHOR]

Background: This study aimed to illustrate the prevalence of CHD by screening children in extremely high-altitude areas (over 4000 m to even 5000 m above sea level) and explore an aid model for early diagnosis and treatment for the Tibetan population. Methods: A total of 2242 students from different schools in Ngamring County, Xigaze City, Tibet from September 2019 to September 2020 were selected for screening. The students were examined through the inquiry of their current medical history and family history, cardiac auscultation and a physical examination, in order to screen out the suspected cases of CHD, and then the suspected cases were confirmed by cardiac color ultrasound examinations. After that, positive patients were be transferred to Shandong Province for free treatment. Results: The prevalence of CHD among children in Ngamring County was 3.70% (83 cases), which is the highest incidence rate ever reported. The most common type of CHD was patent ductus arteriosus (PDA), accounting for 55.42% of the total number of cases screened, followed by atrial septal defect (ASD) and ventricular septal defect (VSD), accounting for 28.92% and 12.05%, respectively. The prevalence of CHD in children at high altitude was significantly higher than that in children at low altitude. The children with CHD were transferred to Shandong Province for surgery, the operations were successful and their recoveries went well. Conclusions: The results show that high altitude is closely related to the prevalence of CHD, and the incidence in Ngamring County is much higher than that in previous reports. [ABSTRACT FROM AUTHOR]

Tibet, which is characterized by collisional orogens, has undergone the process of delamination or convective removal. The lower crust and mantle lithosphere appear to have been removed through delamination during orogenic development. Numerical and analog experiments demonstrate that the metamorphic eclogitized oceanic subduction slab or lower crust may promote gravitational instability due to its increased density. The eclogitized oceanic subduction slab or crustal root is believed to be denser than the underlying mantle and tends to sink. However, the density of eclogite under high-pressure and high-temperature conditions and density differences from the surrounding mantle is not preciously constrained. Here, we offer new insights into the derivation of eclogite density with a single experiment to constrain delamination in Tibet. Using in situ synchrotron X-ray diffraction combined with diamond anvil cell, experiments focused on minerals (garnet, omphacite, and epidote) of eclogite are conducted under simultaneous high-pressure and high-temperature conditions, which avoids systematic errors. Fitting the pressure-temperature-volume data with the third-order Birch-Murnaghan equation of state, the thermal equation of state (EoS) parameters, including the bulk modulus (KT0), its pressure derivative (KT0'), the temperature derivative (KT)P), and the thermal expansion coefficient (α0), are derived. The densities of rock-forming minerals and eclogite are modeled along with the geotherms of two types of delamination. The delamination processes of subduction slab breakoff and the removal of the eclogitized lower crust in Tibet are discussed. The Tibetan eclogite which containing 40-60 vol. % garnet and 37-64 % degrees of eclogitization can promote the delamination of slab break-off in Tibet. Our results indicate that eclogite is a major controlling factor in the initiation of delamination. A high abundance of garnet, a high Fe-content, and a high degree of eclogitization are more conducive to instigating the delamination. [ABSTRACT FROM AUTHOR]