Geodesic Distance Function Learning via Heat Flow on Vector Fields

Learning a distance function or metric on a given data manifold is of great importance in machine learning and pattern recognition. Many of the previous works first embed the manifold to Euclidean space and then learn the distance function. However, such a scheme might not faithfully preserve the distance function if the original manifold is not Euclidean. Note that the distance function on a manifold can always be well-defined. In this paper, we propose to learn the distance function directly on the manifold without embedding. We first provide a theoretical characterization of the distance function by its gradient field. Based on our theoretical analysis, we propose to first learn the gradient field of the distance function and then learn the distance function itself. Specifically, we set the gradient field of a local distance function as an initial vector field. Then we transport it to the whole manifold via heat flow on vector fields. Finally, the geodesic distance function can be obtained by requiring its gradient field to be close to the normalized vector field. Experimental results on both synthetic and real data demonstrate the effectiveness of our proposed algorithm

One reference genome is not enough.

A recent study on human structural variation indicates insufficiencies and errors in the human reference genome, GRCh38, and argues for the construction of a human pan-genome

Latest lessons from the bankruptcy of state-owned enterprises (SOEs) in China : an interpretative structural model (ISM) approach

State-owned enterprises (SOEs) play an important role in China. During the transformation from a planned to a market economy, plenty of Chinese SOEs fell into trouble. Dalian machine tool group (DMTG) who was once a leading enterprise in the Chinese machine tool industry bankrupted in 2017. To explore the causes of its collapse, we employ the interpretative structural model (ISM) to investigate the reasons for its failures from multi-aspect and at different levels. The results indicate that the root cause of this bankruptcy is the top manager’s mismanagement; the lack of a reasonable strategic positioning and long-term product planning are also important factors of DMTG’s failure, and the problems of human resource management accelerated the bankruptcy. Findings provide lessons to be learned from the bankruptcy for SOEs and offer managerial insight into SOEs.Peer ReviewedPostprint (published version

Analysis of taxi travels during an epidemic period using system dynamics method

This paper explores the factors influencing taxi travel in the context of COVID-19 from both demand and supply sides and provides a quantitative comparison of taxi travel characteristics and taxi industry operations before and after the epidemic. A model was established using system dynamics to simulate a taxi travel system, which was used to analyze the changes in demand and supply of taxi travel under scenarios such as closedowns, travel restrictions, etc. The analysis is based on a typical middle-sized city in China, Ningbo in Zhejiang Province, revealing factors leading to the significant drop in the amount of taxi travel due to the epidemic. The study can provide insights into impacts of public (or similar anomalous or catastrophic) events on taxi travel systems and could be useful for urban transport planning and management.Postprint (published version

UCP2 Inhibits ROS-Mediated Apoptosis in A549 under Hypoxic Conditions

The Crosstalk between a tumor and its hypoxic microenvironment has become increasingly important. However, the exact role of UCP2 function in cancer cells under hypoxia remains unknown. In this study, UCP2 showed anti-apoptotic properties in A549 cells under hypoxic conditions. Over-expression of UCP2 in A549 cells inhibited reactive oxygen species (ROS) accumulation (P<0.001) and apoptosis (P<0.001) compared to the controls when the cells were exposed to hypoxia. Moreover, over-expression of UCP2 inhibited the release of cytochrome C and reduced the activation of caspase-9. Conversely, suppression of UCP2 resulted in the ROS generation (P = 0.006), the induction of apoptosis (P<0.001), and the release of cytochrome C from mitochondria to the cytosolic fraction, thus activating caspase-9. These data suggest that over-expression of UCP2 has anti-apoptotic properties by inhibiting ROS-mediated apoptosis in A549 cells under hypoxic conditions

Evaluation of pharmacokinetics and toxicology of biosimilar APZ001 antibody in Macaca cynomolgus

Purpose: To compare the pharmacokinetics of APZ001 antibody with those of cetuximab (Erbitux®) and to evaluate the toxicology of the former.Methods: To evaluate cetuximab’s biosimilar APZ001, Crl:CD1(ICR) (CD-1) mice and Macaca fascicularis (cynomolgus monkey) were chosen for the studies on acute toxicity, chronic toxicity, pharmacokinetics in chronic toxicity and immunogenicity toxicity. The study also compared the pharmacokinetic parameters of APZ001 with those of cetuximab upon single and multiple drug administrations in cynomolgus monkeys.Results: Pharmacokinetic parameters including maximum concentration (Cmax) and time to attain maximum drug concentration (Tmax), clearance rate and apparent volume of distribution of APZ001 were compared with those of cetuximab in both single and multiple administration studies. Difference of pharmacokinetics from weekly administration of APZ001 and cetuximab in cynomolgus monkeys was insignificant (p &gt; 0.05), with relative bioavailability of 116.9 %. Both APZ001-treated and cetuximabtreated CD-1 mice showed the same level of food intake and body weight. Hematological and serological data were similar from APZ001 antibody and cetuximab treatments, so were the acute and chronic toxicity. Weekly transfusion of APZ001 did not alter its pharmacokinetic parameters. The administered drug was hardly detected in the serum in the 31st and 37th week of recovery; no accumulation of drug was observed upon withdrawal.Conclusion: APZ001 has extremely similar characteristics as cetuximab in terms of pharmacokinetics and toxicity.Keywords: Cetuximab, Pharmacokinetics, Acute toxicity, Chronic toxicity, Immunogenicity, Biosimila

ANALYSIS OF SWITCHGRASS CHARACTERISTICS USING NEAR INFRARED SPECTROSCOPY

Switchgrass varieties grown under various environments were investi-gated by dispersive and Fourier Transform Near-Infrared (NIR) spectro-meters. The collected NIR spectra were analyzed using multivariate approaches. More specifically, principal component analysis (PCA) and projection to latent structures (PLS) regression techniques were employed to classify and predict characteristics of the switchgrass samples. The multivariate results were compared to reflectance indices that are commonly used to study the physiological performance of plants. From near infrared spectra, discrimination between the two growth locations was successfully achieved by PCA. Separation based on the ecotype and the rate of fertilizer applied to the field was also possible by the multivariable analysis of the spectral data. For the classification/ discrimination of the switchgrass samples, the near infrared spectra collected by the dispersive and the Fourier Transform spectrometers provided similar results. From the two near infrared data sets robust models were developed to predict non-structural carbohydrates content and the rate of nitrogen applied to the field. However, the spectra collected by the dispersive spectrometer resulted in more accurate models for these samples

Team Incentives and Lower Ability Workers: An Experimental Study on Real Effort Tasks

Team incentives are important in many compensation systems that pay workers according to the output of their team as well as to their own output, with team bonuses often depending on whether the team meets or exceeds specified thresholds. Yet little is known about how team members with different abilities respond to compensation rules and thresholds. We contrast the performance of lower ability participants and higher ability participants in an experiment with three distribution schemes – equal sharing, piece rate sharing, and tournament style winner-takesall – in settings with and without a team threshold. Workers randomly assigned to equal sharing had higher productivity than those assigned to winner-takes-all and had similar productivity to workers in piece-rate scheme. Output under equal sharing was boosted by the higher productivity of less able workers, possibly motivated by a desire to avoid guilt feelings about letting down their partners, per models of guilt aversion. Given a choice of distribution schemes, participants selected piece rate over equal sharing and favored both of these over winner-takes-all; in addition, a team threshold induced more concern about cooperation and thus greater preference for equal sharing. The findings suggest that organizations with teams of workers with varying abilities are likely to do better if the organization can consider lower ability workers’ responsiveness to sharing in rewards, e.g., to have an equal sharing component in its compensation system when they are strongly guilt averse

BlockEmulator: An Emulator Enabling to Test Blockchain Sharding Protocols

Numerous blockchain simulators have been proposed to allow researchers to simulate mainstream blockchains. However, we have not yet found a testbed that enables researchers to develop and evaluate their new consensus algorithms or new protocols for blockchain sharding systems. To fill this gap, we develop BlockEmulator, which is designed as an experimental platform, particularly for emulating blockchain sharding mechanisms. BlockEmulator adopts a lightweight blockchain architecture such that developers can only focus on implementing their new protocols or mechanisms. Using layered modules and useful programming interfaces offered by BlockEmulator, researchers can implement a new protocol with minimum effort. Through experiments, we test various functionalities of BlockEmulator in two steps. Firstly, we prove the correctness of the emulation results yielded by BlockEmulator by comparing the theoretical analysis with the observed experiment results. Secondly, other experimental results demonstrate that BlockEmulator can facilitate the measurement of a series of metrics, including throughput, transaction confirmation latency, cross-shard transaction ratio, the queuing size of transaction pools, workload distribution across blockchain shards, etc. We have made BlockEmulator open-source in Github