This paper proposes the hybrid NM-PSO algorithm based on the Nelder–Mead (NM) simplex search method and particle swarm optimization (PSO) for unconstrained optimization. NM-PSO is very easy to ...implement in practice since it does not require gradient computation. The modification of both the Nelder–Mead simplex search method and particle swarm optimization intends to produce faster and more accurate convergence. The main purpose of the paper is to demonstrate how the standard particle swarm optimizers can be improved by incorporating a hybridization strategy. In a suite of 20 test function problems taken from the literature, computational results via a comprehensive experimental study, preceded by the investigation of parameter selection, show that the hybrid NM-PSO approach outperforms other three relevant search techniques (
i.e., the original NM simplex search method, the original PSO and the guaranteed convergence particle swarm optimization (GCPSO)) in terms of solution quality and convergence rate. In a later part of the comparative experiment, the NM-PSO algorithm is compared to various most up-to-date cooperative PSO (CPSO) procedures appearing in the literature. The comparison report still largely favors the NM-PSO algorithm in the performance of accuracy, robustness and function evaluation. As evidenced by the overall assessment based on two kinds of computational experience, the new algorithm has demonstrated to be extremely effective and efficient at locating best-practice optimal solutions for unconstrained optimization.
Summary
Background
Patients with nonalcoholic steatohepatitis (NASH) have gut dysbiosis and intestinal bacterial overgrowth.
Aim
To test the hypothesis that endotoxemia is associated with the ...histological severity of nonalcoholic fatty liver disease (NAFLD) and determine factors associated with endotoxemia.
Methods
The endotoxemia markers lipopolysaccharide‐binding protein (LBP) and endotoxin levels were measured in 237 NAFLD patients 1 day before liver biopsy. Biomarkers of liver injury and transient elastography were performed as additional markers of disease severity.
Results
A total of 114/237 (48%) patients had NASH and 80/237 (34%) had F2‐4 fibrosis. LBP was correlated with lobular inflammation (P=.001), while both LBP (P=.0004) and endotoxin levels (P=0.008) were correlated with fibrosis. LBP was also correlated with cytokeratin‐18 fragments (P=.002) and aspartate aminotransferase‐to‐alanine aminotransferase ratio (P=.006), and both LBP (P=.019) and endotoxin (P=.006) were correlated with liver stiffness measurement by transient elastography. LBP was increased in patients with NASH (15.3±4.6 vs 13.8±3.3 μg/mL; P=.005) and F2‐4 fibrosis (15.4±4.4 vs 14.0±3.7 μg/mL; P=.008). Interestingly, patients harbouring the TM6SF2 rs58542926 T allele that predispose to NAFLD/NASH had higher LBP level. By multivariate analysis, gender, higher body mass index and glycated haemoglobin, and TM6SF2 variants were independent factors associated with increased LBP level.
Conclusions
Endotoxemia is positively associated with NASH and significant fibrosis. The association between TM6SF2 and endotoxemia warrants further investigations. The findings may shed light on the pathogenesis of NASH and inform a novel treatment target.
Linked ContentThis article is linked to Valenti and Romeo paper. To view this article visit https://doi.org/10.1111/apt.14154.
We study the fiscal implications of interest rate normalization from the zero lower bound (ZLB) in the United States. At the ZLB, falling tax revenues and real bond prices increase government debt ...accumulation. During normalization, interest payments remain above the path without the ZLB, and government debt can increase further despite the recovery of output and tax revenues. Against the yardstick of ability to pay, interest rate normalization is unlikely to threaten federal debt sustainability at the current net federal debt level about 100% of GDP. If the government fails to reform Social Security and major healthcare programs, sovereign default risk can rise more quickly when debt reaches 150% of GDP. Also, a more active monetary policy anchors inflation expectations better, generates a faster recovery and, hence, slows down debt accumulation more than a less active one does. An unexpected early liftoff, however, can prolong a recession and increase debt accumulation more at the ZLB and during normalization.
Résumé
Répercussions fiscales de la normalisation des taux d'intérêt aux États‐Unis. Nous étudions les répercussions fiscales de la normalisation des taux d'intérêt du taux plancher zéro aux États‐Unis. Au taux plancher zéro, la diminution des recettes fiscales et des coûts des obligations réels fait grimper la dette publique. Pendant la normalisation, les paiements d'intérêt restent supérieurs au parcours sans taux plancher zéro. En dépit du redressement de la production et des recettes fiscales, la dette publique peut prendre de l'ampleur. À l'aune de la capacité de payer, il est improbable que la normalisation des taux d'intérêt vienne menacer la viabilité de la dette publique au taux actuel de dette publique nette, soit environ 100 % du PIB. Si le gouvernement ne parvient pas à réformer les programmes de sécurité sociale et les principaux programmes d'assurance maladie, le risque de défaillance d'un emprunteur souverain pourrait augmenter plus rapidement lorsque la dette atteint 150 % du PIB. De plus, des politiques monétaires plus rigoureuses parviennent à mieux ancrer les attentes quant à l'inflation et à produire un redressement plus rapide que ne le ferait une politique moins active, aidant à ralentir l'accumulation de dettes durant la normalisation. Or, un départ précoce inattendu pourrait prolonger la récession, augmentant du coup l'accumulation de dettes au taux plancher zéro et durant la normalisation.
Large expansionary fiscal measures are often implemented with monetary accommodation during an economic crisis. When a government is highly indebted, and the timing of switching to the conventional ...regime M (passive fiscal/active monetary policies) is uncertain, a government spending increase in regime F (active fiscal/passive monetary policies) increases government debt. Such regime uncertainty dampens inflation and debt revaluation effects. Also, as regime uncertainty generates a smaller real interest rate decline, debt servicing costs fall less, and tax revenues increase less, than in the fixed regime F. These factors contribute to reversing the debt decline for a spending increase in the fixed regime F. The result holds under adverse supply shocks and potentially higher capital taxes, relevant factors in the post-COVID U.S. economy.
The early Paleozoic geological evolution of the South China Craton composed of the Yangtze and Cathaysia Blocks has been the focus of long debate. The Cathaysia block has been central to the ...controversy regarding convergent margin versus intraplate environment in the early Paleozoic. In order to address the early Paleozoic evolution of Cathaysia, we undertook a systematic study of the stratigraphic sequences, deformational features and geochronology of magmatic event. Our results show that (1) during the early Paleozoic, the Jiangnan domain of the SE Yangtze block was characterized by a carbonate platform and the Cathaysia block by a graptolite-facies clastic rock assemblage, (2) in the Cathaysia block, a littoral-neritic depositional environment prevailed in Cambrian whereas a neritic-bathyal setting dominated during the early-middle Ordovician, and (3) the Late Ordovician depositional sequence in Cathaysia witnessed a period of transition from neritic-bathyal to littoral-land environment, marking the initial uplift process. Paleo-current measurements on the crossbeds revealed northwestward and westward transport directions, suggesting a source area to the east-southeast. All samples collected from the Cambrian-Ordovician strata show similar chemical characteristics; they have negative ...(t) values (-9.7 to -13.7) and two-stage ...Nd(t) model ages at ca.2.04 to 2.36 Ga. This suggests that the early Paleozoic rocks were derived from the eroded Paleoproterozoic basement, and little or no mantle component was identified. During the Silurian, the Cathaysia block underwent strong folding, thrusting, weak metamorphism and large-scale anatexis accompanied by granitoid emplacement, building the South China Fold Belt. The maximum shortening is estimated at 67 percent. A kinematic analysis of the ductile sheared rocks revealed a fan-shape thrust pattern, with top-to-the southeast in the southeastern and top-to-the northwest in the northwestern Cathaysia block. Zircon U-Pb dating of four granitic plutons yielded 206Pb/238U ages of 435 ± 4 Ma, 424 ± 5 Ma, 428 ± 3 Ma and 427 ± 2 Ma. All the zircon ...Hf(t) values are negative (-6 to -9) and show a peak of two-stage Hf model ages around 1.9 Ga, indicating that the Silurian granitic magma was derived from the recycling of Paleoproterozoic basement. Major features of the early Paleozoic South China Fold Belt include the lack of early Paleozoic ophiolites and volcanic rocks, the absence of coeval HP-type blueschists, and the absence of mantle-derived juvenile magmatic rocks. Consequently, a subduction-collision-type orogeny is excluded. The magmatism most probably took place in an intraplate tectonic setting with little or no input of mantle components. We therefore conclude that the South China Fold Belt was an intraplate orogen, and is possibly related to the global early Paleozoic continental assembly. (ProQuest: ... denotes formulae/symbols omitted.)
•Downward nominal wage rigidity generates business cycle-dependent government spending multipliers.•Government spending in recessions reduces unemployment and does not drive up the real interest rate ...as much as in expansions.•The baseline simulation generates an impact output multiplier of 1.37 in recession and of 0.54 in expansion.•The theoretical implications are consistent with empirical responses of key macro variables in the literature.
Despite much empirical evidence on business cycle-dependent government spending multipliers, the theoretical channels underlying such results are uncertain. In an environment with involuntary unemployment, this paper shows that downward nominal wage rigidity, which arises only in recessions, can generate business cycle-dependent government spending multipliers. In line with Keynesian views, a demand stimulus reduces unemployment in recessions and may not drive up inflation and wages as in expansions. Thus, the positive income effects from reduced unemployment and weaker crowding-out effects from a smaller increase in the real interest rate enhance the expansionary spending effects in recessions. The theoretical implications are largely consistent with existing empirical evidence on business cycle-dependent government spending effects on key macroeconomic variables.
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