METARO^(3):Metamorphic Relation Group for Automatic Program Repair

The application of metamorphic testing(MT)on automatic program repair(APR-MT)is used to generate a patch without test oracles by examining whether the input metamorphic relation(MR)is satisfied or not.However,the delivered patch is plausible since it may satisfy the input MR but violate other MRs.This inspires us to propose an improved approach to enhance the effectiveness of APR-MT with metamorphic relation group.Ourapproach involves three major steps.First,we formally define the repair process of APR-MT by building the model of automatic program repair and metamorphic testing separately.Then,we propose the advanced model of automatic program repair based on metamorphic relation group,named METARO^(3),which takes several MRs as input while only one MR is used in APR-MT.We additionally present two kinds of selection strategies to rank MRs in descending order of the fault detection capability,which helps shorten the repair time of finding a patch.To demonstrate the feasibility and procedure of our approach,an illustration example was conducted.The results show that METARO^(3) can improve the effectiveness of APR-MT significantly.

中国海洋生物地理学研究进展和热点:物种分布模型及其应用

海洋生物地理学是研究海洋生物地理分布时空格局、形成过程及其影响因素的学科,对于生物多样性保护、生态系统结构稳定以及海洋资源可持续利用具有重要支撑作用。物种分布模型是研究物种地理分布变化的重要手段,其发展对于海洋生物地理学的发展具有重要的推动作用。本文综述了中国海洋生物地理学的发展历程和现状;提供了物种分布模型的定义、类型、发展历程及相关重要数据库;整理分析了中国海洋生物地理学研究中的部分热点问题,主要涉及全球变化下海洋生物分布区变化、海洋生物谱系地理结构、海洋生物入侵、种群连通性、海洋保护规划、海洋生态修复、海洋生物对极端环境适应、海洋渔业资源管理和海水养殖规划等。本文同时对海洋生物地理学研究的未来发展进行了展望,强调了改进物种分布模型的重要性,提出要强化环境和生物数据库建设,加强海洋生物地理学与其他学科的交叉融合等。本综述对于今后我国海洋生物地理学的研究,尤其是物种分布模型在相关领域中的应用具有参考价值。

Semantic similarity-based program retrieval:a multi-relational graph perspective

1 Introduction Program retrieval aims to enable the flexible retrieval of program snippets based on a natural language query,significantly accelerating software development productivity.Study shows that over 60%of developers perform program retrieval daily[1].Recent years have witnessed an increasing interest in deep learning-based program retrieval,which aims to construct embedding representations for program snippets and queries.However,the distribution of natural languages and programs is inconsistent,resulting in a semantic gap.The critical challenge is to bridge the semantic gap between the programming language and natural language,and accurately measure their similarity.

Anaerobic metabolism and thermal tolerance:The importance of opine pathways on survival of a gastropod after cardiac dysfunction

Organisms on rocky shores are frequently exposed to high temperatures,which cause impairment of cardiac function and retard cellular oxygen delivery.However,some gastropods can survive at several degrees Celsius higher than their Arrhenius break temperature of cardiac function(ABT),indicating the importance of anaerobic metabolism for their thermal tolerance.We measured the global molecular responses to heat stress in limpet Cellana toreuma using 454 GS-FLX to investigate the variations of genes involved in anaerobic metabolism at high temperatures.Next,the gene expression levels of 4 anaerobic enzymes and activity of alanopine dehydrogenase(AlDH),which is involved in opine pathway,were measured in response to elevated temperature.A total of 19 heat shock proteins(HSPs)were determined using real-time PCR at different temperatures.At high temperatures,the extensive upregulation of HSP genes was an effective but energetically expensive form of protection to prevent thermal damage.The upregulation of hypoxia-inducible factor 1 alpha mRNA indicated the condition of cellular hypoxia and the high gene expression and enzyme activity of AlDH suggested that opine pathway was the main anaerobic pathway.These results implied that anaerobic metabolism was enhanced to provide energy in the face of thermal stress.Our findings highlight the ecological significance of the anaerobic metabolism of gastropods to thermal adaptation.For predicting the ecological impact of global warming on the distribution of gastropods,the role of anaerobic pathways should be evaluated.

Temperature relations of aerial and aquatic physiological performance in a mid-intertidal limpet Cellana toreuma: Adaptation to rapid changes in thermal stress during emersion

The physiological performance of a mid-intertidal limpet Cellana toreuma was determined to study the physiological adaptation of intertidal animals to rapid changes and extreme temperatures during emersion.The relationship between the Arrhenius breakpoint temperature(ABT)and in situ operative body temperature was studied to predict the possible impact of climate change on the species.The temperature coefficient(Q10)of emersed animals was higher than that of submersed animals and the ratio of aerial:aquatic heart rate rose with increasing temperature.The ABTs of submersed and emersed animals were 30.2 and 34.2°C,respectively.The heart rate and levels of molecular biomarkers(hsps,ampkα,ampkβand sirt1 mRNA)were determined in 48 h simulated semi-diurnal tides.There were no obvious changes of heart rate and gene expression during the transition between emersion and submersion at room temperature,although expressions of hsp70 and hsp90 were induced significantly after thermal stress.These results indicate that C.toreuma can effectively utilize atmospheric oxygen,and the higher Q10 and ABT of emersed animals are adaptations to the rapid change and extreme thermal stress during emersion.However,the in situ operative body temperature frequently exceeds the aerial ABT of C.toreuma,indicating the occurrence of large-scale mortality of C.toreuma in summer,and this species should be sensitive to increasing temperature in the scenario of climate change.

Growth,serum biochemical parameters,salinity tolerance and antioxidant enzyme activity of rainbow trout(Oncorhynchus mykiss)in response to dietary taurine levels

This study evaluated the effect of dietary taurine levels on growth,serum biochemical parameters,salinity adaptability,and antioxidant activity of rainbow trout(Oncorhynchus mykiss).Four diets were formulated with taurine supplements at 0,0.5,1,and 2%w/v(abbreviated as To,T05,Tt,and T2,respectively).Rainbow trouts(initial weight of 80.09±4.72 g)were stocked in tanks(180 L capacity),and were fed these diets for six weeks and subsequently underwent salinity acclimation.Physiological indicators were determined before salinity acclimation at 1,4,7,and 14 days afterwards.Results showed that there were no significant differences in growth performance(final mean weight ranged from 182.35 g to 198.48 g;percent weight gain was between 127.68%and 147.92%)of rainbow trout in freshwater stage,but dietary taurine supplement significantly increased serum-free taurine content.After entering seawater,the Na+-K+-ATPase activity of T2 group returned to its freshwater levels,and the serum cortisol content was significantly higher than To and To 5 groups.At the end of this experiment,the liver superoxide dismutase activity in the To and To 5 groups was significantly lower than in the Tj and T2 groups,and the liver catalase in the To group was the lowest whereas that in the T2 group was the highest.Muscle malondialdehyde content was the highest in the To group,and the lowest in the T2 group.Based on the results of this study,supplement of dietary taurine(0.5-2%)enhanced the salinity tolerance in rainbow trout,which increased with the higher taurine concentration.

Effects of balancing selection and microhabitat temperature variations on heat tolerance of the intertidal black mussel Septifer virgatus

Realistic assessments of the impacts of global warming on population extinction risk are likely to require an integrated analysis of the roles of standing genetic variation,microhabitat thermal complexity,and the inter-individual variation of heat tolerance due to both genetic differences and seasonal acclimatization effects.Here,we examine whether balancing selection and microhabitat temperature heterogeneity can interact to enhance the population persistence to thermal stress for the black mussel Septifer virgatus.We deployed biomimetic data loggers on the shore to measure the microhabitat-specific thermal variation from June 2014 to April 2016.Thermal tolerance of specimens was indexed by measuring effects of temperature on heart rate.Genotyping of specimens was performed using double digestion restriction association RADSeq(ddRADseq).Our results show that inter-individual variations in thermal tolerance correlate significantly with genetic differences at some specific gene loci,and that heterozygotes have higher thermal tolerances than homozygotes.The observed seasonal changes in genotype frequency suggest that these loci are under balancing selection.The ability of thermally resistant heterozygotes to survive in sun-exposed microhabitats acts to balance the loss of homozygotes during summer and enable the persistence of genetic polymorphisms.Population persistence of the mussel is also facilitated by the micro-scale variation in temperature,which provides refugia from thermal stress.Our results emphasize that inter-individual variation in thermal tolerance and in microhabitat heterogeneity in temperature are important for the persistence of populations in rocky shore habitats.

HIGH FIDELITY VIRTUALIZATION OF CYBER-PHYSICAL SYSTEMS

Cyber-physical systems(CPS)tightly integrate cyber and physical components and transcend discrete and continuous domains.It is greatly desired that the synergy between cyber and physical components of CPS is explored even before the complete system is put together.Virtualization has potential to play a significant role in exploring such synergy.In this paper,we propose a CPS virtualization approach based on the integration of virtual machine and physical component emulator.It enables real software,virtual hardware,and virtual physical components to execute in a holistic virtual execution environment.We have implemented this approach using QEMU as the virtual machine and Matlab/Simulink as the physical component emulator,respectively.To achieve high-fidelity between the real system and its virtualization,we have developed a strategy for synchronizing the virtual machine and the physical component emulator.To evaluate our approach,we have successfully applied it to real-world control systems.Experiments results have shown that our approach achieves high-fidelity in capturing dynamic behaviors of the entire system.This approach is promising in enabling early development of cyber components of CPS and early exploration of the synergy of cyber and physical components.

High abundance and reproductive output of an intertidal limpet(Siphonaria japonica)in environments with high thermal predictability

The predictability of high temperatures is important for intertidal species for coping with thermal stress.To investigate the roles of high temperature and its predictability on the population abundance and reproductive output of an intertidal rocky shore limpet,Siphonaria japonica,we monitored the operative temperature,recorded the population abundance of egg ribbons and adults,and quantified the expression of heat shock protein 70(hsp70)mRNA on two warm-temperate rocky shores with different thermal environments.Abundances of limpets and egg ribbons in the hotter but more predictable(HP)habitats were higher than those in the relatively benign and unpredictable(BU)habitats.In the HP habitats,there was a strong positive correlation between habitat temperature and population abundance.For limpets living in the HP habitats,the expression of hsp70 exhibited a smaller increase with rising body temperature than for BU limpets,indicating the existence in HP limpets of a preparatory strategy in cellular stress response against thermal stress.Our results dem on strate that the predictability of operative temperature can affect physiological responses and population dynamics.The importance of predictability should be considered in analyses of the ecological consequences of climate warming.