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Efficient Handling of Lock Hand-off in DSM Multiprocessors with Buffering Coherence Controllers

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Journal of Computer Science & Technology 2012年第1期27卷 75-91页

作者： Benjamín Sahelices Agustín de Dios Pablo Ibáez Víctor Vials-Yúfera josé María Llabería Computer Science Department and HiPEAC European network of Excellence University of Valladolid Valladolid Spain Computer Science and Systems Engineering Department I3A Research Institute and HiPEAC European Network of Excellence University of Zaragoza Zaragoza Spain Computer Architecture Department and HiPEAC European network of Excellence Polytechnic University of Catalua Barcelona Spain

Synchronization in parallel programs is a major performance bottleneck in multiprocessor systems. Shared data is protected by locks and a lot of time is spent on the competition arising at the lock hand-off. In order to be serialized, requests to the same cache line can either be bounced （nACKed） or buffered in the coherence controller. In this paper, we focus mainly on systems whose coherence controllers buffer requests. In a lock hand-off, a burst of requests to the same line arrive at the coherence controller. During lock hand-off only the requests from the winning processor contribute to progress of the computation, since the winning processor is the only one that will advance the work. This key observation leads us to propose a hardware mechanism we call request bypassing, which allows requests from the winning processor to bypass the requests buffered in the coherence controller keeping the lock line. We present an inexpensive implementation of request bypassing that reduces the time spent on all the execution phases of a critical section （acquiring the lock, accessing shared data, and releasing the lock） and which, as a consequence, speeds up the whole parallel computation. This mechanism requires neither compiler or programmer support nor ISA or coherence protocol changes. By simulating a 32-processor system, we show that using request bypassing does not degrade but rather improves performance in three applications with low synchronization rates, while in those having a large amount of synchronization activity （the remaining four）, we see reductions in execution time and in lock stall time ranging from 14% to 39% and from 52% to 7170, respectively. We compare request bypassing with a previously proposed technique called read combining and with a system that bounces requests, observing a significantly lower execution time with the bypassing scheme. Finally, we analyze the sensitivity of our results to some key hardware and software parameters.

关键词： distributed shared memory multiprocessors synchronization buffer coherence controller request bypass

Astaxanthin Accumulation in the Green Alga Haematococcus pluvialis： Effects of Cultivation Parameters

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Journal of Integrative Plant Biology 2007年第4期49卷 447-451页

作者： Ping He James Duncan James barber Institute of Botany the Chinese Academy of Sciences Beijing 100093 China Division of Molecular Biosciences Imperial College London London SW7 2AY UK Graduate School of Beijing Forestry University Beijing 100083 China

The green alga, Haematococcus pluvlalis Flotow is used as a source of the ketocarotenoid astaxanthin for application in fish aquaculture, pharmaceutical and cosmetic industries. Ceils of the green alga were induced by the application of different light and starvation conditions to evaluate the effect in astaxanthin accumulate. The conditions used for the Induction were high light intensity （170 μmol·m^-2·s^-1）, iron starvation, sulfur starvation and phosphate starvation. The results show that stresses applied in culture, which interfere with cell division, trigger the accumulation of astaxanthin. notably, sulfur starvation results in a massive accumulation of this commercially important carotenoid.

关键词： astaxanthin Haematococcus pluvialis iron light phosphate stress sulfur.

The sexually dimorphic expression of glutamate transporters and their implication in pain after spinal cord injury

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neural Regeneration Research 2025年第11期20卷 3317-3329页

作者： Jennifer M.Colón-Mercado Aranza I.Torrado-Tapias Iris K.Salgado jose M.Santiago Samuel E.Ocasio Rivera Dina P.Bracho-Rincon Luis H.Pagan Rivera Jorge D.Miranda Department of Physiology University of Puerto RicoMedical Sciences CampusSan JuanPRUSA national Institutes of Health National Human Genome Research InstituteBethesdaMDUSA Universidad Central del Caribe School of MedicineBayamónPRUSA University of Puerto Rico Carolina CampusCarolinaPRUSA Institute of neurobiology San JuanPRUSA

In addition to the loss of motor function,~60% of patients develop pain after spinal cord *** cellular-molecular mechanisms are not well understood,but the data suggests that plasticity within the rostral,epicenter,and caudal penumbra of the injury site initiates a cellularmolecular interplay that acts as a rewiring mechanism leading to central neuropathic *** can lead to the formation of new connections triggering abnormal sensory *** excitatory glutamate transporters are responsible for the reuptake of extracellular glutamate which makes them a critical target to prevent neuronal hyperexcitability and *** previous studies showed a sexually dimorphic therapeutic window for spinal cord injury after treatment with the selective estrogen receptor modulator *** this study,we investigated the anti-allodynic effects of tamoxifen in male and female rats with spinal cord *** hypothesized that tamoxifen exerts anti-allodynic effects by increasing the expression of glutamate transporters,leading to reduced hyperexcitability of the secondary neuron or by decreasing aberrant *** and female rats received a moderate contusion to the thoracic spinal cord followed by subcutaneous slow-release treatment of tamoxifen or matrix pellets as a control(placebo).We used von Frey monofilaments and the“up-down method”to evaluate mechanical *** treatment decreased allodynia only in female rats with spinal cord injury revealing a sexdependent *** expression profile of glutamatergic transporters(excitatory amino acid transporter 1/glutamate aspartate transporter and excitatory amino acid transporter 2/glutamate transporter-1)revealed a sexual dimorphism in the rostral,epicenter,and caudal areas of the spinal cord with a pattern of expression primarily on *** rodents showed a significantly higher level of excitatory amino acid transporter-1 expression while male rodents showed increased

关键词： allodynia central neuropathic pain EAAT-1/GLAST EAAT-2/GLT-1 glutamate transporters selective estrogen receptor modulator sexual dimorphism spinal cord injury trauma

Slip-model Performance for Underexpanded Micro-scale Rocket nozzle Flows

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Journal of Thermal Science 2007年第3期16卷 223-230页

作者： joséA.Morí■igo joséHermidaQuesada Francisco Caballero Requena Dept.of Space Programmes Dept.of

In aerospace Micro-Electro Mechanical Systems （MEMS）, the characteristic length scale of the flow approaches the molecular mean free path, thus invalidating the continuum description and enforcing the use of particle methods, like the Direct Simulation Monte Carlo （DSMC）, to deal with the non-equilibrium regions. Within the slip-regime （0.01〈Kn〈-0.1） both approaches, continuum and particle-based, seem to behave well in terms of accuracy. The present study summarizes the implementation and results obtained with a 2nO-order slip boundary condition in a navier-Stokes solver to address the rarefaction near the nozzle walls. Its assessment and application to a cold-gas micro-scale conical nozzle of 300μm throat diameter, discharging into the low-pressure freestream, constitutes the major aim of the work. The slip-model incorporates the velocity slip with thermal creep and temperature jump, thus permitting to deal with non-isothermal flows as well. Results show that the gas experiences an intense rarefaction in the lip vicinity, pointing to the limits of model validity. Furthermore, a strong Mach deceleration is observed, attributed to the rather thick subsonic boundary layer and supersonic bulk heating caused by the viscous dissipation, in contrast with the expansion to occur in large rocket nozzles during underexpanded operation.

关键词： Slip flow MEMS micronozzles

Multiple primary colorectal cancer: Individual or familial predisposition?

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World Journal of Gastrointestinal Oncology 2015年第12期7卷 434-444页

作者： josé A Pajares josé Perea Department of Gastreoenterology Gregorio Maranon University Hospital Department of Surgery 12 de Octubre University Hospital

Colorectal carcinoma(CRC) is one of the most frequent cancers. Along the surface of the large bowel, several foci of CRC may appear simultaneously or over the time. The development of at least two different tumours has been defined as multiple primary CRC(MPCRC):When more than one tumour is diagnosed at the same time, it is known as synchronous CRC(SCRC), while when a second neoplasm is diagnosed some time after the resection and/or diagnosis of the first lesion, it is called metachronous CRC(MCRC). Multiple issues can promote the development of MPCRC, ranging from different personal factors, such as environmental exposure, to familial predisposition due to hereditary factors. However, most studies do not distinguish this dichotomy. High- and low-pentrance genetic variants are involved in MPCRC. An increased risk for MPCRC has been described in Lynch syndrome, familial adenomatous polyposis, and serrated polyposis. non-syndromic familial CRCs should also be considered as risk factors for MPCRC. Environmental factors can promote damage to colon mucosae that enable the concurrence of MPCRC. Epigenetics are thought to play a major role in the carcinogenesis of sporadic MPCRC. The methylation state of the DnA depends on multiple environmental factors(e.g., smoking and eating foods cooked at high temperatures), and this can contribute to increasing the MPCRC rate. Certain clinical features may also suggest individual predisposition for MPCRC. Different etiopathogenic factors are suspected to be involved in SCRC and MCRC, and different familial vs individual factors may be implicated. MCRC seems to follow a familial pattern, whereas individual factors are more important in SCRC. Further studies must be carried out to know the molecular basis of risks for MPCRC in order to modify, if necessary, its clinical management, especially from a preventive point of view.

关键词： Multiple primary colorectal cancer Synchronous colorectal cancer Metachronous colorectal cancer Chromosomal instability Microsatellite instability CpG island methylator phenotype

Projections of weak braided Hopf algebras

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Science China Mathematics 2011年第5期54卷 877-906页

作者： ALOnSO LVAREZ jos nicanor FERnnDEZ VILABOA jos Manuel GOnZLEZ RODRíIGUEZ Ramón SOnEIRA CALVO Carlos Departamento de Matemticas Universidad de Vigo Vigo E-36310 Spain Departamento de lxebra Universidad de Santiago de Compostela Santiago de Compostela E-15771 Spain Departamento de Matemtica Aplicada II Universidad de Vigo Vigo E-36310 Spain Departamento de Matemticas Universidad de Vigo Vigo E-36004 Spain

In this paper we study the projections of weak braided Hopf algebras using the notion of Yetter-Drinfeld module associated with a weak braided Hopf algebra. As a consequence, we complete the study ofthe structure of weak Hopf algebras with a projection in a braiding setting obtaining a categorical equivalencebetween the category of weak Hopf algebra projections associated with a weak Hopf algebra H living in abraided monoidal category and the category of Hopf algebras in the non-strict braided monoidal category ofleft-left Yetter-Drinfeld modules over H.

关键词： weak Yang-Baxter operator Yetter-Drinfeld module weak (braided) Hopf algebra weak Hopf algebra projection

Response of grease film at low speeds under pure rolling reciprocating motion

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Friction 2020年第1期8卷 115-135页

作者： Yiming HAn Jing WAnG Shanshan WAnG Qian ZOU Gary barber School of Mechanical and Automotive Engineering Qingdao University of TechnologyHuangdao CampusQingdao 266520China School of Engineering and Computer Science Oakland UniversityRochesterMI 48309USA

Using an optical interferometric technique,the grease film distribution under a pure rolling reciprocating motion is observed on a ball‐disk test rig,to explore the transient response of grease,which is expected to fill the contact with thickener fiber and run for a long time under steady‐state *** is found that the reciprocating motion reduces the accumulation of the thickener fiber gradually with *** maximum film thickness forms around the stroke *** 1,000 working cycles,very severe starvation occurs so that either the central or minimum film thickness becomes nearly constant over one working ***,the life of grease lubrication under a transient condition is far below that under steady‐state ***,it is also found that by selecting a smaller stroke length,the thickener fiber spreads out in the contact instead of being removed from the contact at the 1,000th working *** increasing the maximum entraining speed of the reciprocating motion to a certain value,during which the thickener fiber is not expected to accumulate under a steady‐state condition,severe starvation occurs very quickly,causing surface damage.

关键词： grease lubrication reciprocation pure rolling grease starvation thickener fiber

Simultaneous analysis of the intestinal parasites and diet through eDnA metabarcoding

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Integrative Zoology 2023年第3期18卷 399-413页

作者： Xabier CABODEVILLA Benjamín Juan GÓMEZ-MOLInER naiara ABAD María joséMADEIRA Department of Zoology and Animal Cell Biology Faculty of PharmacyUniversity of the Basque Country(UPV/EHU)AlavaSpain Instituto de Investigación en Recursos Cinegéticos(IREC)(CSIC-UCLM-JCCM) Ciudad RealSpain

Agricultural expansion and intensiﬁcation are having a huge impact on plant and arthropod diversity and abun-dance,affecting food availability for farmland ***ﬁcult food access,in turn,can lead to immunosuppression and a higher incidence of *** the studies designed to examine changes in the diet of birds and their par-asites,metabarcoding is proving particularly *** technique requires mini-barcodes capable of amplifying the DnA of target organisms from fecal environmental *** help to understand the impact of agricultural expansion on biodiversity,this study sought to design and identify mini-barcodes that might simultaneously as-sess diet and intestinal parasites from the feces of farmland *** capacity to identify diet and parasites of 2 existing and 3 newly developed mini-barcodes was tested“in silico”in relation to the behavior of a reference eukaryotic *** the newly designed mini-barcodes,MiniB18S_81 showed the higher taxonomic cover-age of eukaryotic taxa and a greater ampliﬁcation and identiﬁcation capacity for diet and parasite ***,when it was tested on fecal samples from 5 different steppe bird species,MiniB18S_81 showed high taxonomic resolution of the most relevant diet and parasite phyla,Arthropoda,nematoda,Platyhelminthes,and Apicomplexa at the order ***,the mini-barcode developed emerges as an excellent tool to simultaneously provide detailed information regarding the diet and parasites of birds,essential for conservation and management.

关键词： biomonitoring broad-spectrum primers eukaryotic mini-barcodes fecal eDnA farmland birds parasitology

Phosphorus fractions and sorption dynamics in the sediments of two Ca-SO4 water reservoirs in the central Argentine Andes

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International Journal of Sediment Research 2017年第3期32卷 442-451页

作者： josé Gabriel León Fernando Luis Pedrozo Pedro Félix Temporetti Instituto Argentino de nivología Glaciología y Ciencias Ambientales (IANIGLA)CCT Mendoza Departamento General de Irrigación Gobierno de Mendoza Espaa y Barcala Instituto de Investigaciones en Biodiversidad y Medio Ambiente (InIBIOMA) CONICET-Universidad Nacional del Comahue

Phosphorus（P） fractionation and sorption behavior were studied in the sediments of two calcium-sulfate(Ca-SO4: Ca2+170 mg L-1; SO42-400 mg L-1) water reservoirs in the southern central Argentine Andes-El Carrizal Reservoir（ECR）,which stratifies in summer and El nihuil Reservoir（EnR）,which is vertically mixed throughout the year. Sediment size classes reflected the lithology of both basins and the reservoirs relative location: ECR（downstream from a valley adjacent to a mountain environment） had higher clay proportions while the sand fraction was more important in EnR（just next to a mountain environment）.In both reservoirs, the chemical composition revealed low alteration and calcium enrichment. Total P content was relatively high(1.1-1.6 mg P kg-1dry weight) as expected from the contribution of marine formations. P fractionation was dominated by Ca-P（ECR, 69% and EnR, 63%） followed by organic-P（23%）in summer-anoxic ECR and by iron/aluminum（Fe/Al）-P（27%） in oxic EnR. Batch experiments showed that sorption behavior in ECR had a typical Langmuir isotherm plot while in EnR that model fitted only at low dissolved P values(nd co-precipitation evidence was observed at higher P concentrations. It is proposed that lower Fe/Al-P content in anoxic（ECR） vs. oxic（EnR） sediments results from the P released from iron-bound phosphorus due to sulfate reduction-ferrous sulfide formation in an anoxic environment. This condition should enable ECR sediments to adsorb P into fresh oxidized iron,and EnR sediments to co-precipitate P with calcium due to Fe/Al-P saturation, as observed in batch experiments. This paper constitutes the first description of phosphorus content and dynamics in reservoir sediments in arid central western Argentina, where water sulfate concentrations are naturally high due to basin lithology.

关键词： Reservoir Internal load Phosphorus binding Calcareous watershed Southern Central Andes