198 research outputs found
Assessment of local outburst flood risk from successive landslides: case study of Baige landslide-dammed lake, upper Jinsha river, eastern Tibet
No full textTwo large landslides in October and November 2018 sequentially dammed the Jinsha river at Baige village, eastern Tibet, China. Subsequently, breaching of each dam induced massive outburst floods that posed a severe threat to downstream cities and infrastructure. Field investigation indicates volumes of the first and second landslide dam are about 24.5 × 106 m3 and 8.53 × 106 m3, respectively. However, the peak discharge of the flood generated from the second landslide (3.1 × 104 m3/s) was significantly larger than that from the first (1.0 × 104 m3/s). The second peak discharge would have been 5.15 × 104 m3/s if the dam breached naturally. In this study, we developed two geometry parameters: effective dam height He (elevation difference between overtopping level and river bottom) and a narrowing number distribution Nr(H) (measures the degree to which a river section is occupied by landslide materials to elevation H) which represents river section narrowing effects of successive landslides. Using numerical simulations, we show that He dominates peak discharge, and it has a linear relationship with peak discharge with slope of 1009.4 m2/s. Furthermore, the dam includes two sub-areas: a higher part (SB-1) and a lower part (SB-2). Two floods only eroded SB-2. However, breaching of SB-1 and breached SB-2 still narrowed the river. The narrowing effects of the first and second breached dam on the river channel are around 0.35 and 0.5, respectively. Spillway and landslide runup deposits increased the local flood risk by narrowing and lifting the local river section; the first landslide promoted the second landslide, which occupied the same area and forms a dam with high He value. Consequently, a more catastrophic flood could be triggered by a small subsequent landslide. Spatial superposition phenomenon of successive landslides increased the local flood risk. This research quantitatively analyzed the influence of the geometry of dam induced by successive landslides on the process of outburst floods and the risk
A Radiomics-Incorporated Deep Ensemble Learning Model for Multi-Parametric MRI-based Glioma Segmentation
No full textAbstractPurpose: To develop a deep ensemble learning model with a radiomics spatial encoding execution for improved glioma segmentation accuracy using multi-parametric MRI (mp-MRI).
Materials/Methods: This radiomics-incorporated deep ensemble learning model was developed using 369 glioma patients with a 4-modality mp-MRI protocol: T1, contrast-enhanced T1 (T1-Ce), T2, and FLAIR. In each modality volume, a 3D sliding kernel was implemented across the brain to capture image heterogeneity: fifty-six radiomic features were extracted within the kernel, resulting in a 4th order tensor. Each radiomic feature can then be encoded as a 3D image volume, namely a radiomic feature map (RFM). For each patient, all RFMs extracted from all 4 modalities were processed by the Principal Component Analysis (PCA) for dimension reduction, and the first 4 principal components (PCs) were selected. Next, four deep neural networks following the U-net’s architecture were trained for the segmenting of a region-of-interest (ROI): each network utilizes the mp-MRI and 1 of the 4 PCs as a 5-channel input for 2D execution. Last, the 4 softmax probability results given by the U-net ensemble were superimposed and binarized by Otsu’s method as the segmentation result. Three deep ensemble models were trained to segment enhancing tumor (ET), tumor core (TC), and whole tumor (WT), respectively. Segmentation results given by the proposed ensemble were compared to the mp-MRI-only U-net results.
Results: All 3 radiomics-incorporated deep learning ensemble models were successfully implemented: Compared to mp-MRI-only U-net results, the dice coefficients of ET (0.777→0.817), TC (0.742→0.757), and WT (0.823→0.854) demonstrated improvements. Accuracy, sensitivity, and specificity results demonstrated the same patterns.
Conclusion: The adopted radiomics spatial encoding execution enriches the image heterogeneity information that leads to the successful demonstration of the proposed neural network ensemble design, which offers a new tool for mp-MRI-based medical image segmentation.
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Relationship among perceived risk, preventive measures, brand trust and purchase intention in restaurants in San Isidro
No full textEsta investigación tuvo como objetivo determinar si existe relación entre el riesgo percibido, las medidas de prevención, la confianza de marca y la intención de compra en restaurantes de San Isidro por parte de clientes limeños de 25 a 39 años en el 2022. El estudio se basó en la investigación de Chunhao Wei, Han Chen y Yen Ming Lee, realizada en China en el año 2021. Para el desarrollo de este trabajo, se empleó una investigación cuantitativa de alcance correlacional y diseño no experimental transeccional. Se aplicaron 300 encuestas a consumidores limeños, hombres y mujeres que hayan visitado restaurantes en San Isidro previo al inicio de la pandemia del COVID-19 y se encuentren en el rango etario de la muestra.
Este estudio demostró la existencia de correlación entre las variables riesgo percibido y medidas de prevención, así como entre las variables confianza de marca e intención de compra, lo que sugiere que a mayor percepción de riesgo por parte de los comensales limeños, mayor grado de aceptación por las medidas preventivas para combatir la emergencia sanitaria. Sin embargo, no se obtuvo evidencia suficiente para afirmar la existencia de correlación entre más variables. En este contexto, la investigación permitió enfatizar la importancia de incentivar la confianza de marca en los restaurantes, debido a su impacto en la intención de compra de los consumidores.The purpose of this research was to determine if there is a relationship among perceived risk, preventive measures, brand trust, and purchase intention in restaurants in San Isidro by Lima customers between the ages of 25 and 39 in 2022. The study was based on the research of Chunhao Wei, Han Chen and Yen Ming Lee, carried out in China in 2021. For the development of this work, a quantitative investigation of correlational scope and cross-sectional non-experimental design was used. 300 surveys were applied to Lima consumers, men and women who are in the age range of the sample and have visited restaurants in San Isidro prior to the start of the COVID-19 pandemic. This study reveals the existence of a connection between the variables perceived risk and prevention measures, as well as between the variables brand confidence and purchase intention, which suggests that the higher the perception of risk by Lima diners, the higher degree of acceptance for preventive measures to combat the health emergency. However, insufficient evidence was obtained to affirm the existence of a connection between more variables. In this context, the research allowed emphasizing the importance of encouraging brand trust in restaurants, due to its impact on the purchase intention of consumers.TesisODS 3: Salud y bienestarODS 8: Trabajo decente y crecimiento económicoODS 12: Producción y consumo responsable
Chief Information Officer Characteristics and Management Forecast Quality
No full textI examine the association between Chief Information Officer (CIO) characteristics and the quality of management earnings forecasts. CIOs manage and utilize firms' IT resources to provide the internal informational outputs that managers rely on to create management forecasts (Li et al., 2007; Feng et al., 2009). After controlling for the firm-level IT capability using the InformationWeek 500 IT ranking list, I document that firms that hire a CIO are more likely to issue management forecasts than firms without a CIO and firms with a CIO issue more specific forecasts as opposed to a range. However, the quality of the issued forecasts at CIO firms is not significantly higher than those at non-CIO firms, which implies that merely hiring a CIO doesn't necessarily improve the management forecast quality. I next find that a CIO's structural power is positively associated with the management forecast quality, while a CIO's tenure, business education background, and personal awards are not significantly related to management forecast quality. Further, I find that that CIO structural power, business background, and personal awards are positively associated with the firm’s IT capability ranking. This study suggests ways to improve firms’ internal information environment quality by hiring CIOs with a business background and personal awards or empowering their CIOs in terms of structural power (i.e., additional job titles).Embargo status: Restricted until 06/2170. To request the author grant access, click on the PDF link to the left
Polymerization: Effect of nanoconfinement and ionic liquid additive
No full textThe kinetics, thermodynamics, and product properties of polymerization are known to be influenced by properties including the reaction temperature, monomer concentration, initiator, and solvent. In addition, nanoreactors and specific additives may be used as synthetic tools to optimize the polymerization. This work aims to investigate the effect of nanoconfinement on the free radical polymerization of benzyl methacrylate and to study the effect of ionic liquid additive on the step-growth polymerization of bisphenol A dicyanate ester.
The effect of nanoconfinement on the kinetics and thermodynamics of benzyl methacrylate free radical polymerization is investigated using differential scanning calorimetry (DSC). Controlled pore glass (CPG) and ordered mesoporous carbon with pore size ranging from 3 to 8 nm are used as confinement media. The propagation rate in CPG increases as pore size decreases, whereas in mesoporous carbon, the rate decreases. For nanoconfined polymerizations, the rate is proportional to initiator concentration to the one-half power, indicating reaction kinetics similar to the bulk, but longer induction time are observed. Lower conversion is required to reach autoacceleration under nanoconfinement, presumably due to the limited diffusivity and lower termination rate for the confined polymer chains. The molecular weight of the polymer synthesized in the nanopores is generally higher than that obtained in the bulk except at the lowest temperatures investigated. In addition, the apparent activation energy of nanoconfined polymerization is lower than bulk. From the perspective of thermodynamics, the dependence of equilibrium conversion on the temperature is investigated. The entropy loss of the polymer chains due to nanoconfinement is determined using an activity model that relates the entropy loss to the chain length and the size of nanopores. The results are compared with the polymerization of methyl methacrylate.
The kinetics of the trimerization reaction of bisphenol A dicyanate ester with an aromatic imidazolium-based ionic liquid as additive is also studied using DSC. The reaction follows second-order autocatalytic kinetics, and a slight acceleration effect is observed in the presence of the aromatic ionic liquid relative to the neat resin. The activation energy also increases with the ionic liquid additive, whereas the glass transition temperature (Tg) is depressed. A model incorporating diffusion effects is able to describe the dynamic and isothermal curing data for both the neat resin system and that containing aromatic ionic liquid. A comparison with aliphatic-based IL additive indicates that the reaction is more accelerated with aliphatic IL than with the aromatic IL in spite of the fact that the aliphatic additive phase separates during cure.Embargo status: Restricted until 06/2022. To request the author grant access, click on the PDF link to the left
Disk B-spline on S2: A Skeleton-based Region Representation on 2-Sphere
No full textDue to the widespread applications of 2-dimensional spherical designs, there has been an increasing requirement of modeling on the S2 manifold in recent years. Due to the non-Euclidean nature of the sphere, it has some challenges to find a method to represent 2D regions on S2 manifold. In this paper, a skeleton-based representation method of regions on S2, disk B-spline(DBSC) on S2 is proposed. Firstly, we give the definition and basic algorithms of DBSC on S2. Then we provide the calculation method of DBSC on S2, which includes calculating the boundary points, internal points and their corresponding derivatives. Based on that, we give some modeling methods of DBSC on S2, including approximation, deformation. In the end, some stunning application examples of DBSC on S2 are shown. This work lays a theoretical foundation for further applications of DBSC on S2.Computer Graphics ForumCurve and Surface Modeling43
Zographetus rienki Xue & Li & Li & Xie & Chen & Li 2019, sp. nov.
No full textZographetus rienki Xue sp. nov. Type material. HOLOTYPE ♂: Nanling National Nature Reserve, 1150 m, Ruyuan, Guangdong, China, 22.VII.2017, leg. Guoxi Xue [GD7, A55]. PARATYPE: 1♂, Mt. Wuzhishan, 760 m, Hainan, China, 19.V.2019, leg. Guoxi Xue; 1f*, Mt. Shengtangshan, Dayaoshan National Nature Reserve, 1200 m, Guangxi, China, 15.VI.2015, leg. Chunhao Wang [A50]. Description. Male (Fig. 1-A, B). Antennae: 10.5 mm in length, black, ventral side of distal club with white scales, apiculus sharply pointed; nudum 15 in number, orange. Labial palpi: ventral side of second segment covered with yellowish white scales, mixed with dense black scales and hairs; third segment porrect, short, much thicker than shaft of antennae, black, blunt pointed. Dorsal side of head and both sides of thorax and abdomen covered with greenish brown hairs. Forewing: 18 mm in length, dorsal side dark brown, basal area darker and covered with greenish brown scales and short hairs; spots pale yellow, semi-hyaline; discal cell with two separated spots, of which upper one equally sized to subapical dot in space R 5, lower one elongated toward wing base; spot in space Cu 1 big, trapezoidal, inner margin perpendicular to vein Cu 2, outer margin slanted outward; spot in space M 3 cuneiform, not overlapped with that in Cu 1; ventral side ground color dark brown, basal and costal area overlaid with greenish brown scales, base of dorsum with a black hair tuft. Hindwing unmarked, dorsal side dark brown, covered with greenish brown and black hairs; ventral side clad with ochreous scales. Male genitalia (Fig. 2). In dorsal view of tegumen, middle of front margin shallowly concave, middle of distal margin with a small mastoid process. Basal half of uncus tapered in dorsal view, central area transparent; distal portion of uncus elongated, finger like, distal end round and bent downward in lateral view. Gnathos vestigial. Saccus relatively short, slightly bent upward. Basal half of valva with dorsal margin flat and ventral margin constricted. Distal half of valva tapered and bifid into a small erected hump-shaped process and a big approximately triangular plate, dorsal margin of the latter shallowly wavy and armed with sawteeth, distal end round. Aedeagus as long as ventral margin of valva, horn-like in dorsal view, dorsal margin of distal portion deeply concave, ventral margin of distal half convex in lateral view; subzonal sheath twice as long as suprazonal sheath. Juxta broad, V-shaped. Female (Fig. 1-C). Slightly larger than male. Wing pattern similar to that of male, except that the outer margin of spot in space Cu 1 perpendicular to vein Cu 2 rather than oblique. Cilia gray on forewing and yellowish on hindwing. Female genitalia (Fig. 3). In lateral view, papillae anales long elliptical, covered with long hairs. Lamella postvaginalis very wide, middle of distal margin slightly concave. Lamella antevaginalis quadrangular, well developed, with a triangular plate on each side. Ductus bursae tube-like, sclerotized; bursa copulatrix bursiform, without signum. Distribution. Ruyuan (Guangdong), Jinxiu (Guangxi), Hainan. Bionomics. The holotype male was captured at 10:00 am when it was perching on a bush under sunlight, with its forewings semi-erect and hindwings flat. The bush is by the side of an asphalt-paved road which was built several years ago to replace the old sand road. The influence of this asphalt road on butterflies of the reserve is to be studied. The paratype male was discovered nearby a tourist route at 2:00 pm when it suddenly appeared on a leaf, with its wings erect. The paratype female was found resting on the ground near a parking lot in the afternoon. This suggests the new species has some tolerance against human activity. The habitats of the type localities in Guangdong and Guangxi are shown in Fig. 4 and Fig. 5, respectively. Etymology. The new species is named after Dr. Rienk de Jong (Naturalis Biodiversity Center, The Netherlands) for his contribution to the study on taxonomy and biogeography of the Hesperiidae. Based upon de Jong & Treadaway (1993a: 113; 1993b: 77; 2007: 37; 2008: 8), Eliot (1959: 386; 1967: 149, 1992: 362), Evans (1949: 299), de Nicéville (1887: 463), Elwes & Edwars (1897: 203), Fan et al. (2007: 301) and specimens examined, a key to species of the genus Zographetus is given as follows.Published as part of Xue, Guoxi, Li, Meng, Li, Xiaojuan, Xie, Guoguang, Chen, Keda & Li, Jialing, 2019, A new species of the genus Zographetus Watson, 1893 from China (Lepidoptera: Hesperiidae), pp. 255-262 in Zootaxa 4629 (2) on pages 256-259, DOI: 10.11646/zootaxa.4629.2.7, http://zenodo.org/record/326911
Polo-like kinase 3 is associated with poor prognosis and regulates proliferation and metastasis in prostate cancer
No full textChunhao Lin,1,2,* Shoumin Bai,1,3,* Tao Du,4 Yiming Lai,2 Xianju Chen,5 Shengmeng Peng,2 Xiaoming Ma,2 Wanhua Wu,2 Zhenghui Guo,1,2 Hai Huang1,2 1Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China; 2Department of Urology, Sun Yatsen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China; 3Department of Radiation Oncology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China; 4Department of Obstetrics and Gynecology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China; 5Department of Urology, The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen 518017, China *These authors contributed equally to this work Background: Biological mechanism of prostate cancer (PCa) recurrence and progress is complex but many of the key elements are not fully understood. Polo-like kinases (Plks) represent a family of highly conserved serine–threonine kinases that play essential roles in cell cycle progression. Plk3 plays contradictory roles in different cancers. However, the roles of Plk3 in PCa remain largely unexplored. Methods: Kaplan–Meier analysis and Cox regression analysis were performed to evaluate the relationship between Plk3 and prognosis of patients with PCa. Gene set enrichment analysis (GSEA) was conducted to evaluate proliferation and metastasis gene sets using The Cancer Genome Atlas Dataset. MTS assay, clone formation assay, cell migration, and wound healing assay were carried out to investigate biological functions of Plk3. Results: We found that high Plk3 expression was closely correlated with poor prognosis. GSEA revealed that Plk3 was involved in proliferation and metastasis. Loss-of-function assays demonstrated that Plk3 promoted proliferation and metastasis in PCa cells in vitro. Conclusion: We discovered that Plk3 plays a critical role in PCa, indicating that it may be a potential prognostic marker and help predict the progression, especially recurrence of PCa. Keywords: prostate cancer, polo-like kinase 3, recurrence, proliferation, migration, GSE
ChemInform Abstract: Synthesis of 4‐Azachromeno[2,3‐b]indol‐11(6H)‐one and Its Derivatives as Analogues of Ellipticine.
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