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Output-only identification of the modal and physical properties of structures using free vibration response

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Earthquake Engineering and Engineering Vibration 2016年第3期15卷 575-589页

作者： Carlos A.Gaviria luis A.Montejo Civil Engineering Program Facultad de Estudios a DistanciaUniversidad Militar Nueva GranadaColombia Department of Civil Engineering and Surveying University of Puerto Rico at MayaguezMayaguezPR 00681-9000Puerto Rico) Department of Engineering Science and Materials University of Puerto Rico at MayaguezMayaguezPR 00681-9000Puerto Rico

The viability of a complete structural characterization of civil structures is explored and discussed. In particular, the identification of modal （i.e. natural frequencies, damping ratios and modal shapes） and physical properties （i.e. mass and stiffness） using only the structure＇s free decay response is studied. To accomplish this, modal analysis from flee vibration response only （MAFVRO） and mass modification （MM） methodologies are engaged along with Wavelet based techniques for optimal signal processing and modal reconstruction. The methodologies are evaluated using simulated and experimental data. The simulated data are extracted from a simple elastic model of a 5 story shear building and from a more realistic nonlinear model of a RC frame structure. The experimental data are gathered from shake table test of a 2-story scaled shear building. Guidelines for the reconstruction procedure from the data are proposed as the quality of the identified properties is shown to be governed by adequate selection of the frequency bands and optimal modal shape reconstruction. Moreover, in cases where the structure has undergone damage, the proposed identification scheme can also be applied for preliminary assessment of structural health.

关键词： mass modification method output-only modal analysis time-frequency analysis continuous waveletstransform Hilbert transform damping

Prevalence of gastroesophageal reflux disease:a population-based cross-sectional study in southern Chile

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Gastroenterology Report 2020年第4期8卷 286-292,I0001,I0002页

作者： Carlos Manterola luis Grande luis Bustos Tamara Otzen Center of Morphological and Surgical Studies Universidad de La FronteraTemucoChile Department of Surgery Universidad de La FronteraTemucoChile Department of Surgery Hospital del MarUniversitat Auto`noma de BarcelonaBarcelonaSpain Department of Public Health Universidad de La FronteraTemucoChile

Background This study assessed the prevalence of gastroesophageal reflux disease(GERD)in a general adult population from Temuco in southern *** association of GERD with demographic variables was also *** A cross-sectional study among the general population of Temuco in southern Chile was conducted in 2017,using a validated and reliable questionnaire for detecting *** urban area of Temuco,with a population of 245,317 inhabitants(2002 census),was divided into four zones,which were representative of the socioeconomic sectors of the *** sample size was estimated assuming a prevalence of 52.8%,an accuracy of 3.0%,a confidence level of 95.0%,and a design effect of *** sampling was used to build *** prevalence of GERD was determined and associated factors were studied by means of bivariate and multivariate *** A total of 1,069 subjects(47.9%women,median age 40 years)from the selected subareas were *** prevalence of GERD was 44.8%.The most frequently reported symptom was regurgitation(54.8%).One-third of subjects took medication to control symptoms and was considered‘sick’by the instrument,although>68%of them had never sought medical *** was a significant association between GERD and age(P<0.001)and female gender(P=0.001).Conclusions In this population-based study,the prevalence of GERD was high(44.8%).GERD was associated with age and female gender.

关键词： gastroesophageal reflux disease prevalence cross-sectional studies evidence-based medicine clinical epidemiology

Dobesilate for dry age-related macular degeneration

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Journal of Biomedical Science and Engineering 2013年第10期6卷 8-14页

作者： Pedro cuevas luis A.Outeirino Carlos Azanza Javier Angulo Guillermo Giménez-Gallego Departamento de Investigación IRYCISHospital Universitario Ramón y CajalMadridSpain Departamento de Oftalmología Hospital de Día Pío XIIMadridSpain Departamento de Estructura y Función de Proteínas Centro de Investigaciones BiológicasCSICMadridSpain

We have evaluated the effects of intravitreal dobesilate, a synthetic fibroblast growth factor inhibitor, in patients with dry age-related macular degeneration, an inflammatory-related retinal disease without available treatment up to date. 36 eyes from 36 patients with dry age-related macular degeneration were treated with a single intravitreal dobesilate injection. The end points were the improvement from baseline visual acuity and normalization of retinal histology at one month. Intravitreal dobesilate injection resulted in a significant improvement in functional and anatomical outcomes at one month after injection. Our results suggest that intravitreal dobesilate may increase the chance of visual acuity gain in dry age-related macular degeneration, even in cases with initial low vision. This study supports the findings of previously published case reports, regarding the short-term improvement in visual acuity by intravitreal dobesilate injection in different degenerative retinal diseases.

关键词： Dry Age-Related Macular Degeneration Fibroblast Growth Factor Inhibition Intravitreal Dobesilate

CFD modelling:The most useful tool for developing mesoscale urban canopy parameterizations

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Building Simulation 2021年第3期14卷 407-419页

作者： Riccardo Buccolieri Jose luis Santiago Alberto Martilli Dipartimento di Scienze e Tecnologie Biologiche edAmbientali University ofSalentoS.P.6 Lecce-MonteroniLecce 73700Italy Environment Department Research Center for EnergyEnvironment and Technology(CIEMAT)Madrid 28040Spain

1 Introduction The fact that most of the world’s population lives in cities(UN-Habitat 2016)has increased interest in urban *** models,such as the Weather Research and Forecasting(WRF)model(***/weather-research-and-forecasting-model),are used to reproduce the meteorology and climatology over cities and around them,where the complex interactions between the atmosphere and urban surfaces(buildings,vegetation,urban obstacles,etc.)induce strong heterogeneity in the flow properties within the urban canopy layer(UCL)(Di Sabatino et al.2013;Lateb et al.2016;Tominaga and Stathopoulos 2016).

关键词： meteorology urban forecasting

Assessment of wear micromechanisms on a laser textured cemented carbide tool during abrasive-like machining by FIB/FESEM

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Friction 2021年第3期9卷 656-664页

作者： Shiqi FANG Dirk BÄHRE luis LLANES Institute of Production Engineering Saarland UniversitySaarbrücken 66123Germany CIEFMA-Department of Materials Science and Engineering EEBE-Campus Diagonal BesòsUniversitat Politècnica de CatalunyaBarcelona 08019Spain

The combined use of focused ion beam(FIB)milling and field-emission scanning electron microscopy inspection(FESEM)is a unique and successful approach for assessment of near-surface phenomena at specific and selected *** this study,a FIB/FESEM dual-beam platform was implemented to docment and analyze the wear micromechanisms on a laser-surface textured(LST)hardmetal(HM)*** particular,changes in surface and microstructural integrity of the laser-sculptured pyramids(effective cutting microfeatures)were characterized after testing the LST-HM tool against a steel workpiece in a workbench designed to simulate an external honing *** was demonstrated that:(1)laser-surface texturing does not degrade the intrinsic surface integrity and tool effectiveness of HM pyramids;and(2)there exists a correlation between the wear and loading of shaped pyramids at the local ***,the enhanced performance of the laser-textured tool should consider the pyramid geometry aspects rather than the microstructure assemblage of the HM grade used,at least for attempted abrasive applications.

关键词： focused ion beam(FIB) field-emission scanning electron microscopy inspection(FESEM) cemented carbides laser surface texturing abrasive machining processes wear

Linear viscoelastic behavior of asphalt binders and mixtures containing very high percentages of reclaimed asphalt pavement

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Frontiers of Structural and Civil Engineering 2023年第8期17卷 1211-1227页

作者： Reza IMANINASAB luis LORIA-SALAZAR Alan CARTER Construction Engineering Department École de Technologie Supérieure(ÉTS)University of QuebecMontreal H3C 1K3Canada Civil Engineering Department Universidad Isaac NewtonSan José10108Costa Rica

The primary aim of this study is to correlate the impact of aggregates,if any,on the viscoelastic behavior of rejuvenated asphalt mixtures containing very high amounts of reclaimed asphalt pavement(RAP)(>50%).First,gradation of 100%RAP was rectified,using a modified Bailey method by adding virgin aggregates to achieve two coarse dense-graded and one fine dense-graded *** modulus test was then performed from−35 to+35℃and 0.01–10 *** addition to performance grade(PG)testing,extracted and recovered binders from different asphalt mixtures underwent shear complex modulus test within−8℃to high temperature PG and frequencies from 0.001 to 30 ***−Cole,Black space,complex modulus and phase angle master curves were constructed and ShiftHomothety-Shift in time-Shift(SHStS)transformation was used to compare the linear viscoelastic behavior of asphalt binders and *** influence of aggregates on the viscoelastic behavior of asphalt mixtures depends on temperature and/or *** role of asphalt binders in the behavior of asphalt mixtures is more pronounced at high temperatures and the effect of the aggregate structure increases as the temperature *** maximum difference(60%to 70%)in the viscoelastic behavior of the binder and mixture based on SHStS transformed Cole−Cole curves is within the phase angle of 15°–20°.

关键词： RAP complex modulus SHStS transformation rejuvenation behavior of asphalt binder and mixture

A renewal theory based performance and configuration framework of the IEEE 802.11ah RAW mechanism

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Digital Communications and Networks 2023年第1期9卷 236-251页

作者： Hamid Taramit luis Orozco-Barbosa Abdelkrim Haqiq Hassan First University of Settat Faculty of Sciences and TechniquesComputerNetworksMobility and Modeling Laboratory:IR2M26000 SettatMorocco Albacete Research Institute of Informatics Universidad de Castilla-La Mancha02006 AlbaceteSpain

IEEE 802.11ah is a new Wi-Fi standard for sub-1Ghz communications,aiming to address the challenges of the Internet of Things(IoT).Significant changes in the legacy 802.11 standards have been proposed to improve the network performance in high contention scenarios,the most important of which is the Restricted Access Window(RAW)*** mechanism promises to increase the throughput and energy efficiency by dividing stations into different *** this scheme,only the stations belonging to the same group may access the channel,which reduces the collision probability in dense ***,the standard does not define the RAW grouping *** this paper,we develop a new mathematical model based on the renewal theory,which allows for tracking the number of transmissions within the limited RAW slot contention period defined by the *** then analyze and evaluate the performance of RAW *** also introduce a grouping scheme to organize the stations and channel access time into different groups within the ***,we propose an algorithm to derive the RAW configuration parameters of a throughput maximizing grouping *** additionally explore the impact of channel errors on the contention within the time-limited RAW slot and the overall RAW optimal *** presented analytical framework can be applied to many other Wi-Fi standards that integrate periodic channel *** simulations using the MATLAB software validate the analytical model and prove the effectiveness of the proposed RAW configuration scheme.

关键词： IEEE 802.11ah Performance evaluation Renewal theory RAW mechanism Internet of things

Low phase angle is associated with the development of hepatic encephalopathy in patients with cirrhosis

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World Journal of Gastroenterology 2016年第45期22卷 10064-10070页

作者： Astrid Ruiz-Margáin Ricardo Ulises Macías-Rodríguez Javier Ampuero Francisco Javier Cubero luis Chi-Cervera Silvia L Ríos-Torres Andrés Duarte-Rojo Ángeles Espinosa-cuevas Manuel Romero-Gómez Aldo Torre Department of Gastroenterology Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán14080 México City México Department of Internal Medicine Ⅲ University Hospital RWTH Aachen52074 Aachen Germany Unit for the Clinical Management of Digestive Diseases Virgen del Rocio-Virgen Macarena University Hospital41009 Sevilla Spain Department of Immunology Complutense University School of Medicine28040 Madrid Spain University of Arkansas for Medical Sciences Little Rock AR 72205 United States Department of Nephrology and Mineral Merabolism Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán México City 14080 México

AIM Evaluate the association between phase angle and the development of hepatic encephalopathy in the longterm follow-up of cirrhotic *** This was a prospective cohort study. Clinical, nutritional and biochemical evaluations were performed. MannWhitney's U and χ2 tests were used as appropriate. Kaplan-Meier curves and Cox proportional Hazards analysis were used to evaluate the prediction and incidence of hepatic *** Two hundred and twenty were included; the most frequent etiology of cirrhosis was hepatitis C infection, 52% of the patients developed hepatic encephalopathy(18.6% covert and 33.3% overt); the main precipitating factors were infections and variceal bleeding. KaplanMeier curves showed a higher proportion of HE in the group with low phase angle(39%) compared to the normal phase angle group(13%)(P = 0.012). Furthermore, creatinine and phase angle remained independently associated to hepatic encephalopathy in the Cox regression multivariate analysis [hazard ratio = 1.80(1.07-3.03)]. CONCLUSION In our cohort of patients low phase angle was associated with an increased incidence of hepatic encephalopathy. Phase angle is a useful nutritional marker that evaluates cachexia and could be used as a part of the integral assessment in patients with cirrhosis.

关键词： Malnutrition Hepatic encephalopathy Phase angle Cachexia Prognosis

Singular Integrals with Variable Kernels in Dyadic Settings

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Acta Mathematica Sinica,English Series 2023年第8期39卷 1565-1579页

作者： Hugo AIMAR Raquel CRESCIMBENI luis NOWAK IMAL-CONICET and UNL Santa FeArgentina Departamento de Matemática FaEAUNCo.and IITCI-CONICETNeuquenArgentina

In this paper we explore conditions on variable symbols with respect to Haar systems,defining Calderón–Zygmund type operators with respect to the dyadic metrics associated to the Haar bases. We show that Petermichl’s dyadic kernel can be seen as a variable kernel singular integral and we extend it to dyadic systems built on spaces of homogeneous type.

关键词： Singular integrals spaces of homogeneous type Petermichl’s operator Haar basis