New radiolarian ages show that the island arc-related Acoje block of the Zambales Ophiolite Complex is possibly of Late Jurassic to Early Cretaceous age.Radiometric dating of its plutonic and volcanichypabyssal rocks ...New radiolarian ages show that the island arc-related Acoje block of the Zambales Ophiolite Complex is possibly of Late Jurassic to Early Cretaceous age.Radiometric dating of its plutonic and volcanichypabyssal rocks yielded middle Eocene ages.On the other hand,the paleontological dating of the sedimentary carapace of the transitional mid-ocean ridge-island arc affiliated Coto block of the ophiolite complex,together with isotopic age datings of its dikes and mafic cumulate rocks,also yielded Eocene ages.This offers the possibility that the Zambales Ophiolite Complex could have:(1)evolved from a Mesozoic arc(Acoje block)that split to form a Cenozoic back-arc basin(Coto block),(2)through faulting,structurally juxtaposed a Mesozoic oceanic crust with a younger Cenozoic lithospheric fragment or(3)through the interplay of slab rollback,slab break-off and,at a later time,collision with a microcontinent fragment,caused the formation of an island arc-related ophiolite block(Acoje)that migrated trench-ward resulting into the generation of a back-arc basin(Coto block)with a limited subduction signature.This Meso-Cenozoic ophiolite complex is compared with the other oceanic lithosphere fragments along the western seaboard of the Philippines in the context of their evolution in terms of their recognized environments of generation.展开更多
Rollback is a synchronization mechanism in optimistic parallel discrete event simulation （PDES）. A basic and popular realization of rollback is based on cancellation of error executed messages. In this paper, severa...Rollback is a synchronization mechanism in optimistic parallel discrete event simulation （PDES）. A basic and popular realization of rollback is based on cancellation of error executed messages. In this paper, several cancellation strategies are introduced, and a new method proposed. Performance comparison is made based on experimental results.展开更多
The Baingoin batholith is one of the largest granitic plutons in the North Lhasa terrane.Its petrogenesis and tectonic setting have been studied for decades,but remain controversial.Here we report data on geochronolog...The Baingoin batholith is one of the largest granitic plutons in the North Lhasa terrane.Its petrogenesis and tectonic setting have been studied for decades,but remain controversial.Here we report data on geochronology,geochemistry and isotopes of Early Cretaceous granitoids within the Baingoin batholith,which provide more evidence to uncover its petrogenesis and regional geodynamic processes.The Early Cretaceous magmatism yields ages of 134.4–132.0 Ma and can be divided into I-type,S-type and highly fractionated granites.The I-and S-type granites exhibit medium SiO2,high K_(2)O/Na_(2)O with negativeεNd(t)andεHf(t)values,whereas,the albite granites have very high SiO_(2)(79.04%–80.40%),very low K_(2)O/N_(2)O,negativeεNd(t)and a large variation inεHf(t).Our new data indicate that these granitoids are derived from unbalanced melting in a heterogeneous source area.The granodiorites involved had a hybrid origin from partial melting of basalt-derived and Al-rich rocks in the crust,the porphyritic monzogranites being derived from partial melting of pelitic rocks.The albite granites crystallized from residual melt separated from K-rich magma within the‘mush’process and underwent fractionation of K-feldspar.We believe that the Early Cretaceous magmatism formed in an extensional setting produced by the initial and continuous rollback of a northward-subducting slab of the NTO.展开更多
Tomographic perfusion imaging is a significant imaging modality for stroke diagnosis.However,the low rotational speed of the C-arm(6–8 s per circle)is a challenge for applying perfusion imaging in C-arm cone beam com...Tomographic perfusion imaging is a significant imaging modality for stroke diagnosis.However,the low rotational speed of the C-arm(6–8 s per circle)is a challenge for applying perfusion imaging in C-arm cone beam computed tomography(CBCT).Traditional reconstruction methods cannot remove the artifacts caused by the slow rotational speed or acquire enough sample points to restore the time density curve(TDC).This paper presents a dynamic rollback reconstruction method for CBCT.The proposed method can improve the temporal resolution by increasing the sample points used for calculating the TDC.Combined with existing techniques,the algorithm allows slow-rotating scanners to be used for perfusion imaging purposes.In the experiments,the proposed method was compared with other dynamic reconstruction algorithms based on standard reconstruction and the temporal interpolation approach.The presented algorithm could improve the temporal resolution without increasing the X-ray exposure time or contrast agent.展开更多
Anatolia is the global archetype of tectonic escape,as witnessed by the devastating 2023 KahramanmaraşEarthquake sequence,and the 2020 Samos Earthquake,which show different kinematics related to the framework of the e...Anatolia is the global archetype of tectonic escape,as witnessed by the devastating 2023 KahramanmaraşEarthquake sequence,and the 2020 Samos Earthquake,which show different kinematics related to the framework of the escape tectonics.Global Positioning System(GPS)motions of the wedge-shaped plate differ regionally from northwestwards to southwestwards(from east to west).Anatolia was extruded westward from the Arabian-Eurasian collision along the North and East Anatolian fault systems,rotating counterclockwise into the oceanic free-faces of the Mediterranean and Aegean,with dramatic extension of western Anatolia in traditional interpretations.However,which is the dominant mechanism for this change in kinematics,extrusion related to the Arabia/Eurasia collision or rollback of the African slab beneath western Anatolia is still unclear.To assess the dominant driving mechanisms across Anatolia,we analyze recent GPS velocity datasets,and decomposed them into N-S and E-W components,revealing that westward motion is essentially constant across the whole plate and consistent with the slip rates of the North and East Anatolia fault zones,while southward components increase dramatically in the transition area between central and western Anatolia,where a slab tear is suggested.This phenomenon is related to different tectonic driving mechanisms.The ArabiaEurasia collision drives the Anatolian Plate uniformly westwards while western Anatolia is progressively more affected by the southward retreating African subducting slab west of the Aegean/Cypriot slab tear,which significantly increases the southward component of the velocity field and causes the apparent curve of the whole modern velocity field.The 2020 and 2023 earthquake focal mechanisms also confirm that the northward colliding Arabian Plate forced Anatolia to the west,and the retreating African slab is pulling the upper plate of western Anatolian apart in extension.We propose that the Anatolian Plate is moving westwards as one plate with an additional component of extension in its west caused by the local driving mechanism,slab rollback(with the boundary above the slab tear around Isparta),rather than separate microplates or a near-pole spin of the entire Anatolian Plate,and the collisionrelated extrusion is the dominant mechanism of tectonic escape.展开更多
Network of workstations (NOW) now becomes one of the main trends of parallel computing. But for long-running scientific programs, it needs effective fault tolerance for its changing property. Checkpointing and rollbac...Network of workstations (NOW) now becomes one of the main trends of parallel computing. But for long-running scientific programs, it needs effective fault tolerance for its changing property. Checkpointing and rollback recovery is a solution to this problem. First the main problems upon rollback recovery are discussed, the different checkpointing techniques for NOW are analyzed, and then the design and implementation of ChaRM (checkpoint-based rollback recovery and process migration) system are described. The comparison of three coordinated checkpointing systems is given.展开更多
Wide-area systems are becoming a popular infrastructure for long-running applications. Rollback- recovery, as a common technology for fault tolerance and load balance, must meet the challenges of scal- ability and inh...Wide-area systems are becoming a popular infrastructure for long-running applications. Rollback- recovery, as a common technology for fault tolerance and load balance, must meet the challenges of scal- ability and inherent variability in such applications. Most of the rollback-recovery protocols, however, are poor in scalability. Although pessimistic message logging protocols have no such problem, their fault-free overhead sometimes is prohibitive. Aiming at good scalability and acceptable overhead, this paper intro- duces the concept of pessimism grain and presents a coarse-grained pessimistic message-logging scheme. The paper also evaluates the impact of pessimism grain on the performance of the recovery scheme. Ex- perimental results show that pessimism grain is one of the key configuration parameters to reach a desired performance level. In practice, the proper pessimism grain should be selected based on the characteristics of the applications.展开更多
基金support from the University of the PhilippinesNational Institute of Geological Sciencesfinancial support from the Department of Science and Technology through the years
文摘New radiolarian ages show that the island arc-related Acoje block of the Zambales Ophiolite Complex is possibly of Late Jurassic to Early Cretaceous age.Radiometric dating of its plutonic and volcanichypabyssal rocks yielded middle Eocene ages.On the other hand,the paleontological dating of the sedimentary carapace of the transitional mid-ocean ridge-island arc affiliated Coto block of the ophiolite complex,together with isotopic age datings of its dikes and mafic cumulate rocks,also yielded Eocene ages.This offers the possibility that the Zambales Ophiolite Complex could have:(1)evolved from a Mesozoic arc(Acoje block)that split to form a Cenozoic back-arc basin(Coto block),(2)through faulting,structurally juxtaposed a Mesozoic oceanic crust with a younger Cenozoic lithospheric fragment or(3)through the interplay of slab rollback,slab break-off and,at a later time,collision with a microcontinent fragment,caused the formation of an island arc-related ophiolite block(Acoje)that migrated trench-ward resulting into the generation of a back-arc basin(Coto block)with a limited subduction signature.This Meso-Cenozoic ophiolite complex is compared with the other oceanic lithosphere fragments along the western seaboard of the Philippines in the context of their evolution in terms of their recognized environments of generation.
基金Project supported by Applied Materials Foundation of ShanghaiMunicipal Commission of Science and Technology ( Grant No .0215)
文摘Rollback is a synchronization mechanism in optimistic parallel discrete event simulation （PDES）. A basic and popular realization of rollback is based on cancellation of error executed messages. In this paper, several cancellation strategies are introduced, and a new method proposed. Performance comparison is made based on experimental results.
基金supported by grants from the National Key R&D Program of China(Nos.2022YFC2905001,2018YFC0604106 and 2018YFC0604101)the Program of the Chinese Geological Survey(Nos.DD20190167 and DD20221684)+1 种基金the Basic Research Fund of the Institute of Mineral Resources,Chinese Academy of Geological Sciences(Nos.SYSCR2019-03 and KK2017)the National Natural Science Foundation of China(No.41902097).
文摘The Baingoin batholith is one of the largest granitic plutons in the North Lhasa terrane.Its petrogenesis and tectonic setting have been studied for decades,but remain controversial.Here we report data on geochronology,geochemistry and isotopes of Early Cretaceous granitoids within the Baingoin batholith,which provide more evidence to uncover its petrogenesis and regional geodynamic processes.The Early Cretaceous magmatism yields ages of 134.4–132.0 Ma and can be divided into I-type,S-type and highly fractionated granites.The I-and S-type granites exhibit medium SiO2,high K_(2)O/Na_(2)O with negativeεNd(t)andεHf(t)values,whereas,the albite granites have very high SiO_(2)(79.04%–80.40%),very low K_(2)O/N_(2)O,negativeεNd(t)and a large variation inεHf(t).Our new data indicate that these granitoids are derived from unbalanced melting in a heterogeneous source area.The granodiorites involved had a hybrid origin from partial melting of basalt-derived and Al-rich rocks in the crust,the porphyritic monzogranites being derived from partial melting of pelitic rocks.The albite granites crystallized from residual melt separated from K-rich magma within the‘mush’process and underwent fractionation of K-feldspar.We believe that the Early Cretaceous magmatism formed in an extensional setting produced by the initial and continuous rollback of a northward-subducting slab of the NTO.
基金supported in part by the State’s Key Project of Research and Development Plan (Nos. 2017YFC0109202,2017YFA0104302)the National Natural Science Foundation (No.61871117)Science and Technology Program of Guangdong (No.2018B030333001)。
文摘Tomographic perfusion imaging is a significant imaging modality for stroke diagnosis.However,the low rotational speed of the C-arm(6–8 s per circle)is a challenge for applying perfusion imaging in C-arm cone beam computed tomography(CBCT).Traditional reconstruction methods cannot remove the artifacts caused by the slow rotational speed or acquire enough sample points to restore the time density curve(TDC).This paper presents a dynamic rollback reconstruction method for CBCT.The proposed method can improve the temporal resolution by increasing the sample points used for calculating the TDC.Combined with existing techniques,the algorithm allows slow-rotating scanners to be used for perfusion imaging purposes.In the experiments,the proposed method was compared with other dynamic reconstruction algorithms based on standard reconstruction and the temporal interpolation approach.The presented algorithm could improve the temporal resolution without increasing the X-ray exposure time or contrast agent.
基金funded by the National Natural Science Foundation of China(Nos.91755213 and 41888101)and the Chinese Scholarship Council.
文摘Anatolia is the global archetype of tectonic escape,as witnessed by the devastating 2023 KahramanmaraşEarthquake sequence,and the 2020 Samos Earthquake,which show different kinematics related to the framework of the escape tectonics.Global Positioning System(GPS)motions of the wedge-shaped plate differ regionally from northwestwards to southwestwards(from east to west).Anatolia was extruded westward from the Arabian-Eurasian collision along the North and East Anatolian fault systems,rotating counterclockwise into the oceanic free-faces of the Mediterranean and Aegean,with dramatic extension of western Anatolia in traditional interpretations.However,which is the dominant mechanism for this change in kinematics,extrusion related to the Arabia/Eurasia collision or rollback of the African slab beneath western Anatolia is still unclear.To assess the dominant driving mechanisms across Anatolia,we analyze recent GPS velocity datasets,and decomposed them into N-S and E-W components,revealing that westward motion is essentially constant across the whole plate and consistent with the slip rates of the North and East Anatolia fault zones,while southward components increase dramatically in the transition area between central and western Anatolia,where a slab tear is suggested.This phenomenon is related to different tectonic driving mechanisms.The ArabiaEurasia collision drives the Anatolian Plate uniformly westwards while western Anatolia is progressively more affected by the southward retreating African subducting slab west of the Aegean/Cypriot slab tear,which significantly increases the southward component of the velocity field and causes the apparent curve of the whole modern velocity field.The 2020 and 2023 earthquake focal mechanisms also confirm that the northward colliding Arabian Plate forced Anatolia to the west,and the retreating African slab is pulling the upper plate of western Anatolian apart in extension.We propose that the Anatolian Plate is moving westwards as one plate with an additional component of extension in its west caused by the local driving mechanism,slab rollback(with the boundary above the slab tear around Isparta),rather than separate microplates or a near-pole spin of the entire Anatolian Plate,and the collisionrelated extrusion is the dominant mechanism of tectonic escape.
基金Project supported by the National "863" High-tech Program of China.
文摘Network of workstations (NOW) now becomes one of the main trends of parallel computing. But for long-running scientific programs, it needs effective fault tolerance for its changing property. Checkpointing and rollback recovery is a solution to this problem. First the main problems upon rollback recovery are discussed, the different checkpointing techniques for NOW are analyzed, and then the design and implementation of ChaRM (checkpoint-based rollback recovery and process migration) system are described. The comparison of three coordinated checkpointing systems is given.
基金the National Natural Science Foundation of China (Nos. 60473031, 60673155)the Natural Science Foundation of Hunan (No. 05JJ30116)
文摘Wide-area systems are becoming a popular infrastructure for long-running applications. Rollback- recovery, as a common technology for fault tolerance and load balance, must meet the challenges of scal- ability and inherent variability in such applications. Most of the rollback-recovery protocols, however, are poor in scalability. Although pessimistic message logging protocols have no such problem, their fault-free overhead sometimes is prohibitive. Aiming at good scalability and acceptable overhead, this paper intro- duces the concept of pessimism grain and presents a coarse-grained pessimistic message-logging scheme. The paper also evaluates the impact of pessimism grain on the performance of the recovery scheme. Ex- perimental results show that pessimism grain is one of the key configuration parameters to reach a desired performance level. In practice, the proper pessimism grain should be selected based on the characteristics of the applications.
