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Lepidium meyenii (Maca) improved semen parameters in adult men

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Asian Journal of Andrology 2001年第4期3卷 301-303页

作者： Gustavo F.Gonzales Amanda Cordova Carla Gonzales arturo Chung Karla Vega arturo Villena Department of Physiological Sciences Faculty of Science and Philosopy and Instituto de Investigacions de la Altura.University Peruana Cayetano HerediaLimaPeru

Aim:The present study was designed to determine the effect of a 4-month oral treatment with tablets of Lepidiwnmeyenii(Maca)on seminal analysis in nine adult normal men aged 24-44 years ***:Nine men receivedtablets of Maca(1500 or 3000 mg/day)for 4 *** analysis was performed according to guidelines of theWorld Health Organization(WHO).Serum luteinizing hormone(LH),follicle stimulating hormone(FSH),prolactin(PRL),testosterone(T)and estradiol(E_(2))were measured before and after ***;Treatment withMaca resulted in increased seminal volume,sperm count per ejaculum,motile sperm count,and sperm *** levels were not modified with Maca *** of sperm count was not related to dose of ***:Maca improved sperm production and sperm motility by mechanisms not related to LH,FSH,PRL,Tand E_(2).

关键词： sperm count sperm motility Peruvian plants Maca Lepidium meyenii

Behavior of ductile steel X-braced RC frames in seismic zones

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Earthquake Engineering and Engineering Vibration 2019年第4期18卷 845-869页

作者： Eber Alberto Godínez-Domínguez arturo Tena-Colunga Facultad de Ingeniería Universidad Autónoma de Chiapas Tuxtla Gutiérrez 29050 Mexico Departamento de Materiales Universidad Autónoma Metropolitana México City 02200 Mexico

A satisfactory ductile performance of moment-resisting reinforced concrete concentric braced frame structures (RC-MRCBFs) is not warranted by only following the provisions proposed in Mexico’s Federal District Code (MFDC-04). The nonlinear behavior of low to medium rise ductile RC-MRCBFs using steel X-bracing susceptible to buckling is evaluated in this study. The height of the studied structures ranges from 4 to 20 stories and they were located for design in the lakebed zone of Mexico City. The design of RC-MRCBFs was carried out considering variable contribution of the two main lines of defense of the dual system (RC columns and steel braces). In order to observe the principal elements responsible for dissipating the earthquake input energy, yielding mappings for diff erent load-steps were obtained using both nonlinear static and dynamic analyses. Some design parameters currently proposed in MFDC-04 as global ductility capacities, overstrength reduction factors and story drifts corresponding to diff erent limit states were assessed as a function of both the considered shear strength and slenderness ratios for the studied RC-MRCBFs using pushover analyses. Additionally, envelopes of response maxima of dynamic parameters were obtained from the story and global hysteresis curves. Finally, a brief discussion regarding residual drifts, residual drift ratios, mappings of residual deformations in steel braces and residual rotations in RC beams and columns is presented. From the analysis of the obtained results, it is concluded that when a suitable design criterion is considered, good structural behavior of RC-MRCBFs with steel-X bracing can be obtained. It is also observed that the shear strength balance has an impact in the height-wise distribution of residual drifts, and an important “shake-down” eff ect is obtained for all cases. There is a need to improve design parameters currently proposed in MFDC to promote an adequate seismic performance of RC-MRCBFs.

关键词： RC braced-frames seismic design nonlinear dynamic analyses steel-X bracing overstrength collapse mechanism story drifts residual drifts

ENVIRONMENTAL ISSUES RELATED TO ENHANCED PRODUCTION OF NATURAL GAS BY HYDRAULIC FRACTURING

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Journal of Green Building 2013年第1期8卷 62-71页

作者： John Walton arturo Woocay University of Texas at El Paso División de Estudios de Posgrado e Investigación Instituto Tecnológico de Ciudad JuárezAve

INTRODUCTION Hydraulic fracturing occurs when high pressure fluids primarily consisting of water and sand are pumped at high pressure into subsurface formations,typically shale that contains natural gas and/or *** high pressure fluid causes the rock to *** new fractures increase the surface area of the shale and better interconnect previously existing fractures,allowing more natural gas and/or oil to be pumped from the *** hydraulic fracturing,referred to as“fracking,”is an evolving technology that largely began after 2000 and has significantly increased natural gas production in the United States in the past five years with corresponding decreases in natural gas prices.

关键词： environmental impact fracking land use and disturbance water and groundwater contamination hydraulic fracturing risk drilling

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

Fertirrigation with Low-Pressure Multi-Gate Irrigation Systems in Sugarcane Agroecosystems:A Review

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Pedosphere 2019年第1期29卷 1-11页

作者： arturo GARCIA-SALDANA Cesareo LANDEROS-SANCHEZ Maria del Refugio CASTANEDA-CHAVEZ Juan Pablo MARTINEZ-DAVILA arturo PEREZ-VAZQUEZ Eugenio CARRILLO-AVILA Postgraduate College Campus Veracruz Tepetates C.P.91674(Mexico) Technological Institute of Boca del Rio(ITBOCA) Boca del Rio C.P.94290(Mexico) Postgraduate College Campus Campeche Campeche C.P.24450(Mexico)

There are very few studies on the application of fertilizers through irrigation water(fertirrigation) using a multi-gate irrigation system in sugarcane AES. Through fertirrigation, the application of fertilizers can be simplified, and their distribution uniformity in sugarcane fields improved. This paper provides an overview of the state of the art regarding fertirrigation with multi-gate irrigation in sugarcane agroecosystems(AES). In order to systematize, organize, and discuss the scientific data on fertirrigation with low-pressure multi-gate irrigation systems in sugarcane AES, bibliographic material from the following full-text scientific journal databases was screened: the Elsevier Science Direct Freedom Collection, Springer Link, and the International Society for Horticultural Science. Next,a matrix of keywords was used to analyze the interrelationships among the available literature, current issues, and the recent *** conclude that development of fertirrigation technologies with low-pressure multi-gate irrigation is much needed.

关键词： climate change crop water requirement fertilizer application fertilizer distribution uniformity sugarcane industry water use efficiency

An Analysis of the Dynamic Behavior of Damaged Reinforced Concrete Bridges under Moving Vehicle Loads by Using the Moving Mesh Technique

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Structural Durability & Health Monitoring 2023年第6期17卷 457-483页

作者： Fabrizio Greco Paolo Lonetti arturo Pascuzzo Giulia Sansone Department of Civil Engineering University of CalabriaVia P.BucciCubo39BRendeCosenza87030Italy

This work proposes a numerical investigation on the effects of damage on the structural response of Reinforced Concrete(RC)bridge structures commonly adopted in highway and railway *** effective three-dimensional FE-based numerical model is developed to analyze the bridge’s structural response under several damage scenarios,including the effects of moving vehicle *** particular,the longitudinal and transversal beams are modeled through solid finite elements,while horizontal slabs are made of shell *** phenomena are also incorporated in the numerical model according to a smeared approach consistent with Continuum Damage Mechanics(CDM).In such a context,the proposed method utilizes an advanced and efficient computational strategy for reproducing Vehicle-Bridge Interaction(VBI)effects based on a moving mesh technique consistent with the Arbitrary Lagrangian-Eulerian(ALE)*** proposed model adopts a moving mesh interface for tracing the positions of the contact points between the vehicle’s wheels and the bridge *** modeling strategy avoids using extremely refined discretization for structural members,thus drastically reducing computational *** analyses in terms of damage scenarios are presented to verify how the presence of damage affects the natural frequencies of the structural *** addition,a comprehensive investigation regarding the response of the bridge under moving vehicles is developed,also providing results in terms of Dynamic Amplification Factor(DAFs)for typical design bridge variables.

关键词： Bridge structures moving mesh technique vehicle-bridge interaction dynamics damage mechanics dynamic amplification factors

Hydrogen production through glycerol steam reforming using Co catalysts supported on SBA-15 doped with Zr,Ce and La

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Journal of Energy Chemistry 2017年第1期26卷 42-48页

作者： Alicia Carrero arturo J.Vizcaíno JoséA.Calles Lourdes García-Moreno Department of Chemical and Energy Technology ESCETRey Juan Carlos University28933 MóstolesSpain

The steam reforming of glycerol has been studied at 500 and 600 oC using Co/SBA-15 and Co/M/SBA-15（M: Zr, Ce, or La） promoted catalysts. The prepared materials were characterized by inductively coupled plasma atomic emission spectroscopy（ICP-AES）, X-ray powder diffraction（XRD）, hydrogen temperatureprogramed reduction（H;-TPR）, ammonia temperature-programed desorption（NH;-TPD）, nitrogen physisorption analysis（N;-BET）, transmission electron microscopy（TEM） and thermogravimetric analysis（TGA）. The incorporation of promoters like Zr, Ce and La on SBA-15 support and successive Co impregnation leaded to smaller cobalt crystallites improving metaldispersion. Besides, stronger metal-support interactions between Co species and M/SBA-15 supports were observed. Thanks to the incorporation of Zr, La and mainly Ce, promoted catalysts present higher glycerol conversion than Co/SBA-15 along 5 h of time on stream. Besides, at 600 oC, Co/M/SBA-15（M: Zr, Ce, or La） catalysts produce higher hydrogen amounts than Co/SBA-15.

关键词： Cobalt SBA-15 Cerium Zirconium Lanthanum Steam reforming Hydrogen

Pacing profiles and tactical behaviors of elite runners

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Journal of Sport and Health Science 2021年第5期10卷 537-549页

作者： arturo Casado Brian Hanley Pedro Jimenez-Reyes Andrew Renfree Faculty of Health Sciences Isabel I UniversityBurgos 09003Spain Carnegie School of Sports Leeds Beckett UniversityLeeds LS63QSUK Centre for Sport Studies Rey Juan Carlos UniversityMadrid 28943Spain Institute of Sport and Exercise Science University of WorcesterWorcester WR26AJUK

The pacing behaviors used by elite athletes differ among individual sports,necessitating the study of sport-specific pacing ***,pacing behaviors adopted by elite runners differ depending on race ***“all-out”strategy,characterized by initial rapid acceleration and reduction in speed in the later stages,is observed during 100 m and 200 m events;400 m runners also display positive pacing patterns,which is characterized by a reduction in speed throughout the ***,800 m runners typically adopt a positive pacing strategy during paced“meet”***,during championship races,depending on the tactical approaches used by dominant athletes,pacing can be either positive or negative(characterized by an increase in speed throughout).A U-shaped pacing strategy(characterized by a faster start and end than during the middle part of the race)is evident during world record performances at meet races in 1500 m,5000 m,and 10,000 m *** a parabolic J-shaped pacing profile(in which the start is faster than the middle part of the race but is slower than the endspurt)can be observed during championship 1500 m races,a negative pacing strategy with microvariations of pace is adopted by 5000 m and 10,000 m runners in championship *** cross country and marathon championship races are characterized by a positive pacing strategy;whereas a U-shaped pacing strategy,which is the result of a fast endspurt,is adopted by 3000 m steeplechasers and half *** contrast,recent world record marathon performances have been characterized by even pacing,which emphasizes the differences between championship and meet races at distances longer than 800 *** reviewed suggest further recommendations for *** the whole race,800 m runners should avoid running wide on the *** turn,during major championship events,1500 m,5000 m,and 10,000 m runners should try to run close to the inside of the track as much as possible during t

关键词： Athletics Distance running Pacing Sprinting

Landform Instability and Land-use Dynamics in Tropical High Mountains, Central Mexico

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Journal of Mountain Science 2012年第3期9卷 414-430页

作者： GARCíA-ROMERO arturo ACEVES-QUESADA José Fernando ARREDONDO-LEóN Carlos Departamento de Geografía Física Instituto de Geografía Universidad Nacional Autónoma de México. Circuito exterior s/n Ciudad Universitaria 04510 Mexico Distrito Federal Mexico Unidad Académica de Estudios Regionales de la Coordinación de Humanidades Universidad Nacional Autónoma de México

This investigation is an analysis of the influence of landform instability on the distribution of land-use dynamics in a hydrographical basin, located in the Mexican Volcanic Belt mountain range (central Mexico), currently affected by substantial changes in land use and deforestation. A landform map was produced, in addition to seven attribute maps - altimetry, drainage density, slope, relief energy, potential erosion, geology and tectonics - which were considered as factors for determining landform instability through Multi-criteria Evaluation Analysis. Likewise, the direction and rhythm of land-use dynamics were analyzed in four dates - between 1976 and 2000 - and cross tabulations were made between them, in order to analyze the trends and processes of land-use dynamics. Afterwards, the databases obtained were cross tabulated with the landform variables to derive areas, percentages and correlation indices. In the study area, high-instability landforms are associated with most ancient volcanic and sedimentary landforms, where high altitude, drainage density, slope and potential to develop gravitational and fluvial processes are the major factors favouring a land-use pattern, dominated by the conservation of extensive forest land, abandonment of human land use and regeneration of disturbed areas. In contrast, low-instability landforms correspond to alluvial plains and lava hills covered by pyroclasts, where low potential erosion to develop fluvial processes, added to water and soil availability and accessibility, have favoured a land-use pattern dominated by the expansion of agroforestry plantations and human settlements, showing a marked trend towards either intensification or permanence of the current land use and with little abandonment and regeneration.

关键词： Landform instability Multi-criteriaEvaluation Analysis Land-use change and processes Tuxpan River Basin