437 research outputs found

    A Multithreaded Soft Processor for SoPC Area Reduction

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    The growth in size and performance of Field Programmable Gate Arrays (FPGAs) has compelled System-on-a-Programmable-Chip (SoPC) designers to use soft proces-sors for controlling systems with large numbers of intellec-tual property (IP) blocks. Soft processors control IP blocks, which are accessed by the processor either as peripheral de-vices or/and by using custom instructions (CIs). In large systems, chip multiprocessors (CMPs) are used to execute many programs concurrently. When these programs require the use of the same IP blocks which are accessed as periph-eral devices, they may have to stall waiting for their turn. In the case of CIs, the FPGA logic blocks that implement the CIs may have to be replicated for each processor. In both of these cases FPGA area is wasted, either by idle soft processors or the replication of CI logic blocks. This paper presents a multithreaded (MT) soft processor for area reduction in SoPC implementations. An MT proces-sor allows multiple programs to access the same IP without the need for the logic replication or the replication of whole processors. We first designed a single-threaded processor that is instruction-set compatible to Alteraā€™s Nios II soft processor. Our processor is approximately the same size as the Nios II Economy version, with equivalent performance. We augmented our processor to have 4-way interleaved mul-tithreading capabilities. This paper compares the area us-age and performance of the MT processor versus two CMP systems, using Alteraā€™s and our single-threaded processors, separately. Our results show that we can achieve an area savings of about 45 % for the processor itself, in addition to the area savings due to not replicating CI logic blocks. 1

    Kirchhoff's Loop Law and the maximum entropy production principle

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    In contrast to the standard derivation of Kirchhoff's loop law, which invokes electric potential, we show, for the linear planar electric network in a stationary state at the fixed temperature,that loop law can be derived from the maximum entropy production principle. This means that the currents in network branches are distributed in such a way as to achieve the state of maximum entropy production.Comment: revtex4, 5 pages, 2 figure

    Orthodontic - Implantoprosthetic Rehabilitation of Hypodontia

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    Prikaz slučaja pacijentice u dobi od 30 godina s hipodoncijom zuba 12. U prvoj fazi liječenja fiksnim ortodontskim aparatom distaliziran je zub 13, u stvoreni prostor u regiji 12 postavljen je zubni usadak te je nakon 6 mjeseci provedena protetska sanacija.A case is presented of a female patient aged 30 years with hypodontia of tooth 12. In the first phase of treatment tooth 13 was distalised by fixed orthodontic apparatus, and a dental implant placed in the area created in region 12 and after 6 months prosthetic treatment was carried out

    Solving Dense Generalized Eigenproblems on Multi-threaded Architectures

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    We compare two approaches to compute a fraction of the spectrum of dense symmetric definite generalized eigenproblems: one is based on the reduction to tridiagonal form, and the other on the Krylov-subspace iteration. Two large-scale applications, arising in molecular dynamics and material science, are employed to investigate the contributions of the application, architecture, and parallelism of the method to the performance of the solvers. The experimental results on a state-of-the-art 8-core platform, equipped with a graphics processing unit (GPU), reveal that in realistic applications, iterative Krylov-subspace methods can be a competitive approach also for the solution of dense problems

    Sympathetic nervous regulation of calcium and action potential alternans in the intact heart

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    Rationale: Arrhythmogenic cardiac alternans are thought to be an important determinant for the initiation of ventricular fibrillation. There is limited information on the effects of sympathetic nerve stimulation (SNS) on alternans in the intact heart and the conclusions of existing studies, focused on investigating electrical alternans, are conflicted. Meanwhile, several lines of evidence implicate instabilities in Ca handling, not electrical restitution, as the primary mechanism underpinning alternans. Despite this, there have been no studies on Ca alternans and SNS in the intact heart. The present study sought to address this, by application of voltage and Ca optical mapping for the simultaneous study of APD and Ca alternans in the intact guinea pig heart during direct SNS. Objective: To determine the effects of SNS on APD and Ca alternans in the intact guinea pig heart and to examine the mechanism(s) by which the effects of SNS are mediated. Methods and Results: Studies utilized simultaneous voltage and Ca optical mapping in isolated guinea pig hearts with intact innervation. Alternans were induced using a rapid dynamic pacing protocol. SNS was associated with rate-independent shortening of action potential duration (APD) and the suppression of APD and Ca alternans, as indicated by a shift in the alternans threshold to faster pacing rates. Qualitatively similar results were observed with exogenous noradrenaline perfusion. In co ntrast with previous reports, both SNS and noradrenaline acted to flatten the slope of the electrical restitution curve. Pharmacological block of the slow delayed rectifying potassium current (I Ks ), sufficient to abolish I Ks -mediated APD-adaptation, partially reversed the effects of SNS on pacing-induced alternans. Treatment with cyclopiazonic acid, an inhibitor of the sarco(endo)plasmic reticulum ATPase, had opposite effects to that of SNS, acting to increase susceptibility to alternans, and suggesting that accelerated Ca reuptake into the sarcoplasmic reticulum is a major mechanism by which SNS suppresses alternans in the guinea pig heart. Conclusions: SNS suppresses calcium and action potential alternans in the intact guinea pig heart by an action mediated through accelerated Ca handling and via increased I Ks

    Side effects and treatment initiation barriers of sodium-glucose cotransporter 2 inhibitors in heart failure: a systematic review and meta-analysis

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    Aims Physicians are sometimes reluctant to initiate guideline-directed therapy in patients with heart failure and reduced ejection fraction (HFrEF) due to concerns of adverse events. We explored the risk of hypotension, volume depletion, and acute kidney injury (AKI) on sodiumā€“glucose cotransporter 2 (SGLT2) inhibitors in HFrEF populations. Methods and results We determined summary risk ratios (RRs) by conducting a meta-analysis on reported aforementioned adverse events on SGLT2 inhibitors from randomized controlled trials. We explored robustness of meta-analyses by computing fragility and/or reverse fragility index (FI or RFI) and its corresponding fragility quotient (FQ or RFQ) for each outcome. A total of 10ā€‰050 patients with HFrEF entered the final meta-analysis. Hypotension was reported in 4.5% (219/4836) on SGLT2 inhibitors and in 4.1% (202/4846) on placebo (RR 1.09, 95% confidence interval [CI] 0.91ā€“1.31, p = 0.36). An RFI of 21 and RFQ of 0.002 suggest robust findings for hypotension. Volume depletion occurred in 9.4% (473/5019) on SGLT2 inhibitors and in 8.7% (438/5031) on placebo (RR 1.07, 95% CI 0.95ā€“1.21, p = 0.25), respectively. RFI of 19 and RFQ of 0.001 suggest moderately robust findings for volume depletion. AKI was reported in fewer patients (1.9% [95/4888]) on SGLT2 inhibitors than on placebo (2.8% [140/4899]) providing lower incidence of AKI (RR 0.69, 95% CI 0.51ā€“0.93, p = 0.02). FI of 14 and RFQ of 0.001 suggest moderately robust findings for AKI. Conclusion Sodiumā€“glucose cotransporter 2 inhibitor therapy is not associated with a clinically relevant risk of hypotension and volume depletion. Its use reduces the risk of AKI. This analysis supports current guideline recommendations on early use of SGLT2 inhibitors
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