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It remains a challenge for existing financial models to accurately capture the shapes of implied volatility (IV) of options with all maturities simultaneously. Inspired by Chen et al.'s empirical finding, 'the shorter the option expiry, the higher the IV is', we propose a novel and simple approach to solve this challenge, by introducing a term-structure-based correction (i.e. an exponential increase function of the options expiry) to the volatility of volatility (vol–vol) term of the classical Heston stochastic volatility model. We derive an approximate formula for the IV under the corrected model with the perturbation method and further apply the formula to predict the IVs of options written on the Shanghai Stock Exchange 50 ETF. Numerical experiments and empirical results show that the introduction of a term-structure-based correction function surely overcomes the deficiency of the classical Heston model in capturing the short-term IVs, thus improving notably its performance of IV forecasting. [ABSTRACT FROM AUTHOR]

In order to cultivate children's computational thinking, researchers have developed many excellent programming systems. Among them, the tangible programming systems combined with graphic output have been widely accepted because of the intuitive input method and diversified visual feedback. However, few of them support collaborative learning or programming. Little is known about children's experiences, emotional states and behaviours on collaborative programming. Motivated by this gap, we present a novel tangible and collaborative enabled programming system named Lighters, which designed for children aged 7–10 and had two types of collaboration modes (block-based and role-based). We conducted an user experiment with 24 children, and collected physiological (EDA), questionnaire, video recording and interview data for analysis. Based on our experiment results, Lighters are effective in helping children learn to program collaboratively. In addition, Lighters can mobilize children's positive emotions and enthusiasm to learn programming. Compared with block-based collaboration, role-based collaboration is more likely to stimulate children's emotional states and has a better effect on learning programming. [ABSTRACT FROM AUTHOR]

Subways are the backbone of many urban transportation systems in large cities around the world. However, disruptions of subway services, such as power-supply failure or signal failures, can cause severe travel delays due to the large carrying capacities of subway trains. Accurate predictions of the disruption durations of subway services are essential for emergency response. To predict the disruption durations of subway services, previous studies primarily used parametric models (e.g., the accelerated failure time (AFT) model), and less attention has been given to machine-learning models with high potential prediction ability and fewer parameter restrictions. This paper proposes a model to predict and explore factors that affect the disruption durations of subway services in Shanghai using machine-learning models. The longitudinal data released by the subway operator from 2012 to 2021 were collected and analyzed in this study. A random survival forest (RSF) was used to describe the disruption durations of the subway service, and influential factors, such as incident reason, incident occurrence time, and line-related variables were considered in the model. Results show that the RSF model (C-Index = 0.672) achieved better prediction accuracy than the traditional AFT model (the best C-Index = 0.609) based on the collected data in Shanghai. In addition, results indicate that incident reason, disruption location, and the time of disruption factors can significantly affect subway service disruption durations. The proposed model can be used as a tool to predict the disruption durations of subway service for better disruption management of the subway system. [ABSTRACT FROM AUTHOR]

Posttranslational modification (PTM) is pivotal for regulating protein functions. Compared to acetylation on lysine residues, the functions and molecular mechanisms of N-terminal acetylation that occur on the first amino acids of proteins are less understood in the macroautophagy/autophagy field. We recently demonstrated that the B-type N-terminal acetyltransferase NatB, formed by the catalytic subunit Nat3 and auxiliary subunit Mdm20, is essential for autophagy. Deficiency of NatB causes blockage of autophagosome formation. We further identified the actin cytoskeleton constituent Act1 and dynamin-like GTPase Vps1 as substrates modified by NatB. The N-terminal acetylation of Act1 promotes its formation of actin filaments and thus facilitates trafficking of Atg9-containing vesicles for autophagosome formation, whereas N-terminal acetylation of Vps1 promotes its interaction with SNARE proteins and facilitates autophagosome-vacuole fusion. Restoring the N-terminal acetylation of Act and Vps1 does not restore autophagy in NatB-deleted cells, suggesting that additional substrates of NatB modification are involved in autophagy regulation. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to investigate the cost-effectiveness of adjuvant treatments in resected pancreatic cancer.Methods: A Markov model was developed to mimic the disease process of postoperative pancreatic cancer, encompassing three health states (relapse-free survival, recurrent disease, and death). Health outcomes and utility scores were derived from the phase III trial and available literature. Cost data were calculated using standard fee data from the West China Hospital for 2017. One-way sensitivity analyses and probabilistic sensitivity analyses were developed to explore model uncertainty.Results: Treatment with S-1 was estimated to yield 1.61 quality-adjusted life-years (QALYs) at a cost of $25,696, whereas treatment with gemcitabine yielded 1.27 QALYs at a cost of $28,930. The incremental cost-effectiveness ratio of S-1 versus gemcitabine was $-9,490 per QALY. Based on the willingness-to-pay threshold of $25,841 per QALY, the net monetary benefit (NMB) was $15,786 for S-1 and $3,727 for gemcitabine, generating the incremental NMB of $12,059. A probabilistic sensitivity analysis revealed that the probabilities of S-1 and gemcitabine being cost-effective were 92% and 8%, respectively. Results were robust to changes in parameters.Conclusion: Adjuvant therapy using S-1 is a cost-effective alternative compared to gemcitabine in patients with postoperative pancreatic cancer from the Chinese societal perspective. [ABSTRACT FROM AUTHOR]

This paper confronts the disparity between a tradition that has defined anthropology as a comparative discipline and the practices which increasingly embrace cultural relativism and the uniqueness of each fieldsite. It suggests that it is possible to resolve this dilemma, through creating a vertical structure that complements the horizontal task of comparison across fieldsites. This vertical structure is composed of different methods of dissemination which make explicit a series of steps from a baseline of popular dissemination which stresses the uniqueness of individuals, through books and journal articles with increasing degrees of generalisation and comparison. Following this structure leads us up through analysis to the creation and employment of theory. This allows us to make comparisons and generalisations without sacrificing our assertion of specificity and uniqueness. We illustrate this argument though a recent nine-field site comparison of the use and consequences of social media in a project called 'Why We Post.' [ABSTRACT FROM AUTHOR]

Polyurethane (PU) is a class of polymers that have been applied for tissue-engineering scaffolds. Cross-linked poly(ester urethane) (CPU), synthesized with ferric catalyst in our laboratory, was modified by silk fibroin (SF) grafting using our aminolysis and glutaradehyde crosslinking method. The physical and chemical properties of the materials were investigated by scanning electron microscope (SEM), atomic force microscope (AFM) and tensile tester. The results showed that SF grafted CPU possessed good strain and strength (4.29 ± 0.18 MPa/382.38 ± 0.71%). Its surface chemistry and roughness were fine to well support the growth of bone marrow mesenchymal stem cells (BMSC). The cells were verified to maintain the pluripotency after they were cultured in vitro for 2 weeks, which supplied us a good technology to keep cell’s stemness but proliferate cell’s number. These results are valuable for us to further study esophageal tissue engineering with BMSC and polyurethane materials as the components. [ABSTRACT FROM AUTHOR]

Monitoring ecological functioning is a significant step towards detecting changes in ecosystem attributes that could be linked to desertification processes in drylands. The remote sensing proxies of ecological functioning, attract substantial attention due to its advantage on large spatial and increasingly long temporal scales. Remote sensed Vegetation Indices (VIs) have been proposed as the approach to plant productivity to be indicators of ecosystem functioning in local drylands. However, VIs are easily affected by rainfall, a limiting source in arid and semi-arid areas. Therefore, they may not be suitable indicators of ecosystem functioning when applied at large scales, with different rainfall regimes. To overcome the influence of precipitation, the performance of the remote sensing Rain-Use Efficiency (RUE, defined as aboveground net primary production divided by rainfall) was evaluated in 78 global drylands (of which 74 are located in semi-arid areas), as an indicator of multiple ecosystem functions, quantified by ecological multifunctionality index (EMI, integrated by carbon, nitrogen and phosphorus cycles). The correlation analysis showed that during the growing season, the linear relationships of summed EVI (Enhanced Vegetation Index) and RUE with EMI are both significant positive. However, RUE explained more variation (about 44%) in EMI than summed EVI (about 32%) did. The results obtained by partial correlation analysis by controlling the rainfall showed that correlation coefficient between summed EVI and EMI, increased about 20%, while correlation coefficient between RUE and EMI increased very slightly (about 3%). Similar results were also found by using the Normalized Difference Vegetation Index (NDVI). These facts indicated that both remote sensed VIs and RUE could be indicators of ecological multifunctioning. However, RUE was better due to its robustness to rainfall. Also, we must take care that the core assumptions related to the RUE should be fulfilled before using it as an indicator. The relationships between RUE and nutrient cycles showed that in comparison to phosphorus cycle, the carbon and nitrogen cycles had an apparent higher weight in determining the relationship between RUE and EMI. Our findings support the use of remote sensed RUE to monitor ecosystem functioning which could be linked with alternative dryland states and early detection of desertification in drylands. [ABSTRACT FROM AUTHOR]

This study mainly focuses on revealing an ancient water landscape at the Longcheng site in the northern Chaohu Lake Basin using very high-resolution (VHR) GeoEye-1 imagery. First, prior to classification, the GeoEye-1 image was processed following atmospheric and geometric correction. The supervised classification was carried out in order to show the land-cover situation in the Longcheng area. The overall classification accuracy was 89.98%, with a kappa coefficient of 0.87. The moat system around the city walls was discovered by using rule-based object-oriented segmentation of the postclassified image, and the other walls of ancient Longcheng were manually identified from the pansharpened VHR GeoEye-1 image. Finally, a map of the ancient water landscape containing the ancient city, wall and moat at the Longcheng site was produced. This paper demonstrates that VHR remote sensing has the ability to uncover an ancient water landscape and provide new insights for archaeological and paleoenvironmental studies. [ABSTRACT FROM AUTHOR]

Determining oil slick thickness plays an important role in assessing oil spill volume and its environmental impacts on the ocean. In this study, we used a Hyperion image of an oil spill accident area and seawater and fresh crude oil samples collected in the Bohai Sea of China. A well-controlled laboratory experiment was designed to simulate spectral responses to different oil slick thicknesses. Spectral resampling and normalization methods were used to reduce the differences in spectral reflectances between the experimental background seawater sample and real background seawater. Fitting the analysis with laboratory experimental data results showed a linear relationship between normalized oil slick reflectance and normalized oil slick thickness [20th band (R2=0.92938,n=49,p<0.01), 26th band (R2=0.93806,n=49,p<0.01), 29th band (R2=0.93288,n=49,p<0.01)]. By using these statistical models, we successfully determined the normalized oil slick thickness with the Hyperion image. Our results indicate that hyperspectral remote sensing technology is an effective method to monitor oil spills on water. The spectral ranges of visible green and red light were the optimal bands for estimating oil slick thickness in case 2 water. The high, stabilized spectral reflectance of background seawater will be helpful in oil slick thickness inversion. [ABSTRACT FROM AUTHOR]