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Energy flow in negative index materials

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Chinese Optics Letters 2004年第7期2卷 428-430页

作者： Lorenzo Bolla michele Midrio Carlo G.Someda The Istituto Nazionale per la Fisica della Materia (I. N. F. M.) Dipartimento di Ingegneria Elettrica Gestionale e Meccanica Universita degli Studi di Udine viale delle Scienze 208 33100 Udine Italy I. N. F. M. Dipartimento di Ingegneria dell'Informazione via G. Gradenigo 6/B 35131 Padova Italy

Prom Maxwell's equations, we compute the speed and the direction of propagation of active power refracted from air into a negative index material. We prove, both analytically and numerically that the power may refract positively even if phase fronts refract negatively. Considerations on the usage of ray optics in problems involving negative index materials are drawn.

关键词： Geometric optics Negative index materials

Simplified seismic performance assessment and implications for seismic design

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Earthquake Engineering and Engineering Vibration 2014年第S1期13卷 95-122页

作者： Timothy J.Sullivan David P.Welch Gian michele Calvi University of Pavia Department of Civil Engineering & ArchitecturePavia 27100Italy European Centre for Training and Research in Earthquake Engineering Pavia 27100Italy UME School ROSE ProgrammeIUSS Pavia PhD candidate IUSS Pavia Professor

The last decade or so has seen the development of refined performance-based earthquake engineering(PBEE) approaches that now provide a framework for estimation of a range of important decision variables,such as repair costs,repair time and number of casualties. This paper reviews current tools for PBEE,including the PACT software,and examines the possibility of extending the innovative displacement-based assessment approach as a simplified structural analysis option for performance assessment. Details of the displacement-based s+eismic assessment method are reviewed and a simple means of quickly assessing multiple hazard levels is proposed. Furthermore,proposals for a simple definition of collapse fragility and relations between equivalent single-degree-of-freedom characteristics and multi-degree-of-freedom story drift and floor acceleration demands are discussed,highlighting needs for future research. To illustrate the potential of the methodology,performance measures obtained from the simplified method are compared with those computed using the results of incremental dynamic analyses within the PEER performance-based earthquake engineering framework,applied to a benchmark building. The comparison illustrates that the simplified method could be a very effective conceptual seismic design tool. The advantages and disadvantages of the simplified approach are discussed and potential implications of advanced seismic performance assessments for conceptual seismic design are highlighted through examination of different case study scenarios including different structural configurations.

关键词： performance-based earthquake engineering displacement-based assessment seismic assessment

Numerical simulation of mud-flows impacting structures

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Journal of Mountain Science 2019年第2期16卷 364-382页

作者： GRECO Massimo DI CRISTO Cristiana IERVOLINO michele VACCA Andrea DICEA Università di Napoli Federico II DI Università della Campania Luigi Vanvitelli

The study of the interaction of mud-flows with obstacles is important to define inundation zones in urban areas and to design the possible structural countermeasures. The paper numerically investigates the impact of a mud-flow on rigid obstacles to evaluate the force acting on them using two different depth-integrated theoretical models, Single-Phase Model(SPM) and Two-Phase Model(TPM), to compare their performance and limits. In the first one the water-sediment mixture is represented as a homogeneous continuum described by a shearthinning power-law rheology. Alternatively, the twophase model proposed by Di Cristo et al in 2016 is used, which separately accounts for the liquid and solid phases. The considered test cases are represented by a 1D landslide flowing on a steep slope impacting on a rigid wall and a 2D mud dam-break flowing on a horizontal bottom in presence of single and multiple rigid obstacles. In the 1D test case, characterized by a very steep slope, the Two-Phase Model predicts the separation between the two phases with a significant longitudinal variation of the solid concentration. In this case the results indicate appreciable differences between the two models in the estimation of both the wave celerity and the magnitude of the impact, with an overestimation of the peak force when using the Single-Phase Model. In the 2D test-cases, where the liquid and solid phases remain mixed, even if the flow fields predicted by the two models present some differences, the essential features of the interaction with the obstacles, along with the maximum impact force, are comparable.

关键词： Mud-Flow Impact force Two-phase model Power-law

Application of first order rate kinetics to explain changes in bloom toxicity——the importance of understanding cell toxin quotas

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Journal of Oceanology and Limnology 2018年第4期36卷 1063-1074页

作者： Philip T.ORR Anusuya WILLIS michele A.BURFORD Australian Rivers Institute Griffith University

Cyanobacteria are oxygenic photosynthetic Gram-negative bacteria that can form potentially toxic blooms in eutrophic and slow flowing aquatic ecosystems. Bloom toxicity varies spatially and temporally, but understanding the mechanisms that drive these changes remains largely a mystery. Changes in bloom toxicity may result from changes in intracellular toxin pool sizes of cyanotoxins with differing molecular toxicities, and/or from changes in the cell concentrations of toxic and non-toxic cyanobacterial species or strains within bloom populations. We show here how first-order rate kinetics at the cellular level can be used to explain how environmental conditions drive changes in bloom toxicity at the ecological level. First order rate constants can be calculated for changes in cell concentration( μ_c : specific cell division rate) or the volumetric biomass concentration( μ_g : specific growth rate) between short time intervals throughout the cell cycle. Similar first order rate constants can be calculated for changes in nett volumetric cyanotoxin concentration( μ_(tox) : specific cyanotoxin production rate) over similar time intervals. How μ_c(or μ_g) covaries with μ tox over the cell cycle shows conclusively when cyanotoxins are being produced and metabolised, and how the toxicity of cells change in response to environment stressors. When μ_(tox)/μ_c >1, cyanotoxin cell quotas increase and individual cells become more toxic because the nett cyanotoxin production rate is higher than the cell division rate. When μ_(tox)/μ_c =1, cell cyanotoxin quotas remains fixed because the nett cyanotoxin production rate matches the cell division rate. When μ_(tox)/μ_c <1, the cyanotoxin cell quota decreases because either the nett cyanotoxin production rate is lower than the cell division rate, or metabolic breakdown and/or secretion of cyanotoxins is occurring. These fundamental equations describe cyanotoxin metabolism dynamics at the cellular level and provide the necessary phys

关键词： cyanotoxin production dynamics first order rate kinetics cyanobacteria

The distribution of COVID-19 mortality

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Infectious Disease Modelling 2022年第4期7卷 856-873页

作者： michele Campolieti Arturo Ramos Department of Management University of Toronto ScarboroughTorontoCanada Departamento de Analisis Economico Universidad de ZaragozaZaragozaSpain

We estimate the distribution of COVID-19 mortality(measured as daily deaths)from the start of the pandemic until July 31st,2022,for six European countries and the *** use the Pareto,the stretched exponential,the log-normal and the log-logistic distributions as well as mixtures of the log-normal and log-logistic *** main results are that the Pareto does not describe well the data and that mixture distributions tend to offer a very good fit to the *** also compute Value-at-Risk measures as well as mortality probabilities with our *** also discuss the implications of our results and findings from the point of view of public health planning and modelling.

关键词： COVID-19 Mortality distribution Pareto Stretched exponential Log-normal and log-logistic distributions Mixture distributions Value-at-Risk measures Tail risks

Rifaximin vs conventional oral therapy for hepatic encephalopathy:A meta-analysis

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World Journal of Gastroenterology 2012年第8期18卷 767-777页

作者： Karim M Eltawil Marie Laryea Kevork Peltekian michele Molinari Department of Surgery and Transplantation Queen Elizabeth Ⅱ Health Sciences Center Dalhousie University Department of Medicine Hepatology and Transplantation Queen Elizabeth Ⅱ Health Sciences Center Dalhousie University

AIM: To characterize the efficacy of rifaximin in the management of hepatic encephalopathy (HE) as several randomized controlled studies have shown contradictory results on its effectiveness in comparison to other oral agents. METHODS: We performed a systematic review and random effects meta-analysis of all eligible trials identifi ed through electronic and manual searches. Twelve randomized controlled trials met the inclusion criteria with a total of 565 patients. RESULTS: The clinical effectiveness of rifaximin was equivalent to disaccharides or other oral antibiotics[odds ratio (OR) 0.96; 95% CI: 0.94-4.08] but with a better safety profi le (OR 0.27; 95% CI: 0.12-0.59). At the completion of treatment protocols, patients receiving rifaximin showed lower serum ammonia levels [weighted mean difference (WMD) = -10.65; 95% CI: -23.4-2.1; P = 0.10], better mental status (WMD = -0.24; 95% CI: -0.57-0.08; P = 0.15) and less asterixis (WMD -0.1; 95% CI -0.26-0.07; P = 0.25) without reaching statistical signifi cance. On the other hand, other psychometric outcomes such as electroencephalographic response and grades of portosystemic encephalopathy were superior in patients treated with rifaximin in comparison to the control group (WMD = 0.21, 95% CI: -0.33-0.09, P = 0.0004; and WMD = -2.33, 95% CI: -2.68-1.98, P = 0.00001, respectively). Subgroup and sensitivity analysis did not show any signifi cant difference in the above fi ndings. CONCLUSION: Rifaximin appears to be at least as effective as other conventional oral agents for the treatment of HE with a better safety profi le.

关键词： Hepatic encephalopathy Lactulose Neo-mycin Non-absorbable disaccharides Rifaximin

Improving the Hydromechanical Deep-Drawing Process Using Aluminum Tailored Heat Treated Blanks

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Acta Metallurgica Sinica(English Letters) 2015年第12期28卷 1482-1489页

作者： Antonio Piccininni Gabriella Di michele Gianfranco Palumbo Donato Sorgente Luigi Tricarico Dipartimento di Meccanica Matematica e Management Politecnico di Bari

The present work demonstrates the effectiveness of combining the hydromechanical deep-drawing process with the Tailored Heat Treated Blank（THTB） technique. In the hydromechanical deep-drawing process, the fluid pressure is used for postponing the fracture occurrence in the blank, while the THTB technique allows to create a material property gradient through a suitable artificial aging treatment carried out prior to the forming process. Since the number of process variables is large, in the present work the authors propose an optimization loop for the determination of the parameters controlling the extension of the blank regions to be subjected to the aging treatment and the temperature levels to be set during the heat treatment. The proposed methodology couples a simple finite element model（Abaqus） with a multiobjective optimization platform（mode FRONTIER）. A preliminary experimental campaign was carried out for determining the effect of the aging treatment on the mechanical（through tensile tests） and deformative（through formability tests）behavior of the AC170 PX aluminum alloy. Optimization results prove the effectiveness of the adopted methodology and put in evidence that the adoption of properly aged blanks in the hydromechanical deep drawing allows to increase the limit drawing ratio and to simplify the process since it is conducted at room temperature.

关键词： Aluminum alloy Aging Hydromechanical deep drawing Finite element analysis Mechanical characterization Formability

Primary sclerosing cholangitis: Updates in diagnosis and therapy

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World Journal of Gastroenterology 2005年第1期11卷 7-16页

作者： Piero Portincasa michele Vacca Antonio Moschetta michele Petruzzelli Giuseppe Palasciano Karel J.van Erpecum Gerard P.van Berge-Henegouwen Section of Internal Medicine Department of Gastroenterology and Hepatology

Primary sclerosing cholangitis (PSC) is a chronic cholestatic syndrome of unknown origin mostly found in males, and characterized by diffuse inflammation and fibrosis of both intra- and extra-hepatic bile ducts. So far, PSC is considered as an autoimmune hepatobiliary disease. In most cases the progression of PSC towards liver cirrhosis and liver failure is slow but irreversible, and liver transplantation is currently the only definitive treatment. In recent years,PSC has been an area of active research worldwide with great interest in etiology, pathogenesis, diagnosis, and therapeutic options such as hydrophilic ursodeoxycholic acid and immunosuppressive agent tacrolimus. Recent updates on clinical and therapeutic aspects of PSC are discussed in the present review.

关键词： Sclerosing cholangitis Diagnosis Therapy

(In)visibilities About the Vulnerabilities of People with Visual Impairments to Disasters and Climate Change:A Case Study in Cuiabaá,Brazil

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International Journal of Disaster Risk Science 2022年第1期13卷 38-51页

作者： Giselly Gomes Victor Marchezini michele Sato Federal University of Mato Grosso(PPGE/UFMT) CuiabaMT 78060-900Brazil ICEMAT-Institute of the Blind of the State of Mato Grosso CuiabaMT 78058-340Brazil Cemaden-National Early Warning and Monitoring Center of Natural Disasters Avenida Altino BondesanDistrito de Eugenio de MeloSao Jose dos CamposSP 12247-016Brazil Doctorate Program on Earth System Science National Institute for Space ResearchSao Jose dos CamposBrazil Programa de Pos-Graduaao em Desastres Naturais ICT/Unesp-CemadenSao Jose dos CamposBrazil

People with visual impairments(PwVI)represent a heterogeneous social group who often experience significant disabling barriers in exercising their rights throughout their life *** dimensions of vulnerability of PwVI to disasters and climate change is an important issue to reduce the culture of neglected *** date,few studies have analyzed visual impairment and disaster risk reduction(DRR)in the countries of Latin America and the *** exploratory qualitative research project analyzed how to include PwVI in the DRR policies of *** research question is:how can we include PwVI in the discussion of DRR and climate change?The response to this question is part of a joint effort that involved a university,a hazard monitoring agency,and three institutions that work with *** three main results of the project are:(1)a mapping method to identify the exposure of PwVI to landslides and floods,and to create tactile risk maps tailored to them;(2)incorporating the voices of PwVI regarding their vulnerabilities and capacities with respect to disasters and climate change,achieved through shared interaction during 15 face to face interviews and one workshop attended by 100 people;and(3)an initiative of inclusive education to reduce some of the disabling barriers that intensify vulnerability.

关键词： Brazil Climate injustice Disaster risk Environmental education Inclusive education Sight impairment