A predictive scoring system for proximal junctional kyphosis after posterior internal fixation in elderly patients with chronic osteoporotic vertebral fracture: A single-center diagnostic study

ObjectiveTo establish a predictive scoring system for proximal junctional kyphosis (PJK) after posterior internal fixation in elderly patients with chronic osteoporotic vertebral fracture (COVF).Materials and methodsThe medical records of 88 patients who were diagnosed with COVF and underwent posterior internal fixation in our hospital from January 2013 to December 2017 were retrospectively analyzed. The included patients were divided into two groups according to whether they suffered PJK after surgery, namely, the PJK group (25 cases) and non-PJK group (63 cases). The following clinical characteristics were recorded and analyzed: age, gender, body mass index (BMI), bone mineral density (BMD), smoking history, fracture segment, proximal junction angle, sagittal vertebral axis, pelvic incidence (PI)–lumbar lordosis (LL), pelvic tilt (PT), sacral slope (SS), posterior ligamentous complex (PLC) injury, upper instrumented vertebra, lower instrumented vertebra, and the number of fixed segments. The prevalence of these clinical characteristics in the PJK group was evaluated, and the scoring system was established using logistic regression analysis. The performance of the scoring system was also prospectively validated.ResultsThe predictive scoring system was established based on five clinical characteristics confirmed as significant predictors of PJK, namely, age > 70 years, BMI > 28 kg/m2, BMD < −3.5 SD, preoperative PI-LL > 20°, and PLC injury. PJK showed a significantly higher score than non-PJK (7.80 points vs. 2.83 points, t=9.556, P<0.001), and the optimal cutoff value for the scoring system was 5 points. The sensitivity and specificity of the scoring system for predicting postoperative PJK were 80.00% and 88.89%, respectively, in the derivation set and 75.00% and 80.00% in the validation set.ConclusionThe predictive scoring system was confirmed with satisfactory sensitivity and specificity in predicting PJK after posterior internal fixation in elderly COVF patients. The risk of postoperative PJK in patients with a score of 6–11 is high, while the score of 0–5 is low

The western extension of Xiahe fault in West Qinling：Discussion on seismogenic structure of Qinghai Zeku MS4.9 earthquake in 2017

The epicenter of the 2017 Qinghai Zeku MS4.9 earthquake was located near the SN-striking Riyueshan fault, while the focal mechanism solutions and the dominant arrangement of seismic sequence are inconsistent with the Riyueshan fault. In this paper, we have discovered EW- and NW-trending faults near the epicenter, by methods of remote sensing interpretation and field investigation. These faults are western terminal structures of Xiahe fault, in which the EW-trending faults are north-dipping and associated with kinematics including both left-lateral and vertical slip. Meanwhile, we use double differential positioning to relocate seismic sequences of Zeku MS4.9 earthquake. Results show that seismic arrangements consist of two segments striking NW and EW. The seismic profile crossing EW-striking segment indicates a north-dipping fault plane. Well consistence is found between Xiahe fault and seismic arrangements of Zeku MS4.9 earthquake, which leads us to the speculation that the seismogenic fault of Zeku earthquake is Xiahe fault. From a regional perspective, the Xiahe fault might be one strand of dissipating faults in the western end of the West Qinling fault, and the Zeku MS4.9 earthquake represents tectonic activity of the western end of the West Qinling fault. Besides，the northwestward turn of fault striking and reverse slipping of Xiahe fault might also be attributed to the right-lateral shearing effects of Riyueshan fault. Results of this paper highlight the significance of improving active fault traces, especially for the secondary or pre-existing faults in a tectonic active area

International Benchmarking of the Individual Tree Detection Methods for Modeling 3-D Canopy Structure for Silviculture and Forest Ecology Using Airborne Laser Scanning

Canopy structure plays an essential role in biophysical activities in forest environments. However, quantitative descriptions of a 3-D canopy structure are extremely difficult because of the complexity and heterogeneity of forest systems. Airborne laser scanning (ALS) provides an opportunity to automatically measure a 3-D canopy structure in large areas. Compared with other point cloud technologies such as the image-based Structure from Motion, the power of ALS lies in its ability to penetrate canopies and depict subordinate trees. However, such capabilities have been poorly explored so far. In this paper, the potential of ALS-based approaches in depicting a 3-D canopy structure is explored in detail through an international benchmarking of five recently developed ALS-based individual tree detection (ITD) methods. For the first time, the results of the ITD methods are evaluated for each of four crown classes, i.e., dominant, codominant, intermediate, and suppressed trees, which provides insight toward understanding the current status of depicting a 3-D canopy structure using ITD methods, particularly with respect to their performances, potential, and challenges. This benchmarking study revealed that the canopy structure plays a considerable role in the detection accuracy of ITD methods, and its influence is even greater than that of the tree species as well as the species composition in a stand. The study also reveals the importance of utilizing the point cloud data for the detection of intermediate and suppressed trees. Different from what has been reported in previous studies, point density was found to be a highly influential factor in the performance of the methods that use point cloud data. Greater efforts should be invested in the point-based or hybrid ITD approaches to model the 3-D canopy structure and to further explore the potential of high-density and multiwavelengths ALS data

Atypical radio pulsations from magnetar SGR 1935+2154

Magnetars are neutron stars with extremely strong magnetic fields, frequently powering high-energy activity in X-rays. Pulsed radio emission following some X-ray outbursts have been detected, albeit its physical origin is unclear. It has long been speculated that the origin of magnetars' radio signals is different from those from canonical pulsars, although convincing evidence is still lacking. Five months after magnetar SGR 1935+2154's X-ray outburst and its associated Fast Radio Burst (FRB) 20200428, a radio pulsar phase was discovered. Here we report the discovery of X-ray spectral hardening associated with the emergence of periodic radio pulsations from SGR 1935+2154 and a detailed analysis of the properties of the radio pulses. The complex radio pulse morphology, which contains both narrow-band emission and frequency drifts, has not been seen before in other magnetars, but is similar to those of repeating FRBs - even though the luminosities are many orders of magnitude different. The observations suggest that radio emission originates from the outer magnetosphere of the magnetar, and the surface heating due to the bombardment of inward-going particles from the radio emission region is responsible for the observed X-ray spectral hardening.Comment: 47 pages, 11 figure

Human Remains from the Pleistocene-Holocene Transition of Southwest China Suggest a Complex Evolutionary History for East Asians

BACKGROUND: Later Pleistocene human evolution in East Asia remains poorly understood owing to a scarcity of well described, reliably classified and accurately dated fossils. Southwest China has been identified from genetic research as a hotspot of human diversity, containing ancient mtDNA and Y-DNA lineages, and has yielded a number of human remains thought to derive from Pleistocene deposits. We have prepared, reconstructed, described and dated a new partial skull from a consolidated sediment block collected in 1979 from the site of Longlin Cave (Guangxi Province). We also undertook new excavations at Maludong (Yunnan Province) to clarify the stratigraphy and dating of a large sample of mostly undescribed human remains from the site. METHODOLOGY/PRINCIPAL FINDINGS: We undertook a detailed comparison of cranial, including a virtual endocast for the Maludong calotte, mandibular and dental remains from these two localities. Both samples probably derive from the same population, exhibiting an unusual mixture of modern human traits, characters probably plesiomorphic for later Homo, and some unusual features. We dated charcoal with AMS radiocarbon dating and speleothem with the Uranium-series technique and the results show both samples to be from the Pleistocene-Holocene transition: ∼14.3-11.5 ka. CONCLUSIONS/SIGNIFICANCE: Our analysis suggests two plausible explanations for the morphology sampled at Longlin Cave and Maludong. First, it may represent a late-surviving archaic population, perhaps paralleling the situation seen in North Africa as indicated by remains from Dar-es-Soltane and Temara, and maybe also in southern China at Zhirendong. Alternatively, East Asia may have been colonised during multiple waves during the Pleistocene, with the Longlin-Maludong morphology possibly reflecting deep population substructure in Africa prior to modern humans dispersing into Eurasia

Deciphering the origin of the Cenozoic intracontinental rifting and volcanism in eastern China using integrated evidence from the Jianghan Basin

Intracontinental rifting and low-volume volcanism are a globally common phenomenon, yet the underlying driving mechanisms and whether they can be explained through classic plate tectonic concepts, remain hotly debated. A prominent example is the Cenozoic rift and volcanic province in eastern China. Using an integration of geological, geophysical and geochemical data, we unravel the spatial and temporal variations of the rifting and volcanism in the Jianghan Basin. Both rifting and volcanism in the Jianghan Basin show two intense-to-weak cycles (65–50 Ma and 50–26 Ma, respectively) with significant enhancement in activity during the late rift phase. Moreover, rifting and depocentres progressively migrated eastward. The Jianghan basalts all share an asthenospheric origin while the source of the late phase basalts is slightly more enriched and heterogenous in Nd-Hf isotopes than that of the early phase basalts. The late phase basalts also display a smaller extent of partial melting even under a thinner lithosphere, likely indicating a significant decrease of volatile content in the mantle source. Based on regional tectonic correlations, the main stages of tectonic evolution of the Jianghan Basin and eastern China are not synchronous with changes in Pacific plate motion, while they are coincident with India-Asia collision processes. These observations lead us to propose that the asthenospheric flow driven by India-Asia collision rather than the rollback of the subducted Pacific slab has caused the widespread rifting and volcanism in eastern China. The variations of rifting and volcanism in the Jianghan Basin suggest a multiphase and eastward asthenospheric flow beneath eastern China driven by India-Asia collision, with an intense upwelling when passing through the North-South Gravity Lineament (NSGL). The much more intense rifting and volcanism during the late rift phase may indicate a much larger scale of volatile-poor asthenospheric flow than the early rift phase which could result in a more intense erosion of ancient enriched lithospheric mantle and the volatile content in the mantle source dropping sharply. This study provides an improved model based on our multidisciplinary observations for asthenospheric flow which may be an alternative driving mechanism for intracontinental rifting and low-volume volcanism in the regions where there are step changes in lithospheric thickness globally

Il ruolo dell'edilizia temporanea nella gestione dell'emergenza sanitaria in Cina

La pandemia che ha colpito il mondo intero a partire dall’anno 2019 sta lasciando un segno decisamente importante nella storia dell’umanità. Il coronavirus, conosciuto anche dal nome del COVID 19, ha stravolto completamente le nostre abitudini e i nostri stili di vita. Numerose sono state le sue conseguenze, a partire dal numero di vittime e dei contagiati. Di conseguenza, le contromisure per il suo contenimento sono state le più severe che l’uomo ha mai adottato, tra cui il lockdown sistematico delle città e la chiusura della frontiera degli Stati. L’applicazione di edilizia temporanea in risposta a questa pandemia senza precedenti merita altrettanti interessi, sul quale è bene fare delle riflessioni e trarre eventualmente spunti per un nuovo know-how per la nostra società. Infatti, all’inizio della pandemia la Cina, paese emblematica di questa pandemia, si è trovata impreparata di fronte all’enorme quantità di pazienti come tutti gli altri paesi e, di conseguenza, ci è stata una carenza elevata di posti letto negli Ospedali e/o strutture sanitarie. Per fortuna, grazie alla volontà politica e la discendenza di una tradizione pragmatica, le soluzioni proposte ed eseguite sono state efficienti e di conseguenza, hanno favorito il contenimento del virus. È comunemente noto che nella gestione di una emergenza il fattore tempo è di fondamentale importanza. Questo significa che le strutture sanitarie di emergenza devono non solo essere dotate di requisiti base di comfort interne, così come quelli sanitari e tecnologici per affrontare una malattia infettiva trasmissibile per via aerea, tra cui una opportuna pressurizzazione delle camere di degenza e la dotazione ad alto contenuto tecnologico nelle sale operatorie, ma anche di requisiti di velocità e facilità nel suo trasporto e posa in opera. Per questi motivi, sono state adottate numerose strategie di costruzione rapide e che tramite questo evento hanno raggiunto la loro nuova frontiera. In questo articolo saranno elencati due di queste, che hanno avuto un ruolo fondamentale in questa pandemia e che, meritano di essere conosciuti per la loro peculiarità