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Alien plant species coexist over time with native ones in Chilean Mediterranean grasslands

Journal of Plant Ecology 2016年第6期9卷 682-691页

作者： Irene Martín-Forés Isabel Castro Belén acosta-Gallo Alejandro del Pozo Laura Sánchez-Jardón JoséM.de Miguel Carlos Ovalle Miguel A.Casado Department of Ecology Complutense University of MadridMadridSpain Department of Ecology Autónoma University of MadridMadridSpain Faculty of Agricultural Sciences University of TalcaTalcaChile Agricultural Research Institute INIA-La Cruz La CruzChile

Aims Alien species are commonly considered as harmful weeds capa-ble of decreasing native biodiversity and threatening *** this assumption,little is known about the long-term patterns of the native-alien relationships associated with human disturbed managed *** study aims to elucidate the commu-nity dynamics associated with a successional gradient in chilean Mediterranean grasslands,considering both native and alien *** Species richness(natives and aliens separately)and life-form(annu-als and perennials)were recorded in four chilean post-agricultural grazed grasslands each covering a broad successional gradient(from 1 to 40 years since crop abandonment).A detrended correspondence analysis(DcA),mixed model effects analyses and cor-relation tests were conducted to assess how this temporal gradient influenced natives and aliens through community *** Findings Our results show different life-form patterns between natives and aliens over *** were mainly represented by annuals(especially ruderals and weeds),which were established at the beginning of *** aliens also predominated at mid-successional stages,but in old grasslands native species were slightly more representative than alien ones within the *** the late successional states,positive or no correlations at all between alien and native species richness suggested the absence of competition between both species groups,as a result of differ-ent strategies in occupation of the *** dynamics over time constitute a net gain in biodiversity,increasing natives and maintaining a general alien pool,allowing the coexistence of *** interactions including facilitation and/or tolerance processes might be occurring in chilean post-agricultural grasslands,a fact that contradicts the accepted idea of the alien species as contenders.

关键词： community dynamics land abandonment gradient life-form livestock grazing successional gradient

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Effectiveness of Gabions Dams on Sediment Retention： A Case Study

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Journal of Environmental Science and Engineering(A) 2016年第10期5卷 516-521页

作者： Leandro Velazquez-Luna Eusebio Ventura-Ramos Josept David Revuelta-acosta Hydraulics Lab. School of Engineering Autonomous University of Queretaro Queretaro 76010 Mexico Department of Agricultural & Biological Engineering Purdue University West Lafayette Indiana 47907 USA

Illegal deforestation changes in land use and climate change have resulted in increased runoff and surface erosion from the upper areas of watersheds, affecting directly the lower lands where human settlements are common. Such is the case of Angangueo in the state ofMichoacam, Mexico, where in 2010 an unusual weather event caused substantial damage to infrastructure, and unfortunately human deaths. Against disasters, the government has carried out actions such as implementing infrastructure to alleviate flooding and mudslides. Gabions dams were used to control erosion and runoff, as they are considered environmentally friendly as compared to most of the constructed impermeable weirs. This study was carried out to evaluate the effectiveness of gabions dams in sediment retention in a small watershed East of Michoacan. Eight gabions dams and five masonry dams two years after of construction were studied. The results indicated that the gabions dams retained less gravel than masonry dams, more sand, but no significant differences were found for fine sediments. Regarding the efficiency of gabions dams, there were not identified relationships since the building volume and contribution area is different in each one of them.

关键词： Weir sediment trap watersheds management.

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Evaluation of Stable Isotopes of Water to Determine Rainwater Infiltration in Soils under Conservation Reserve Program

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Journal of Agricultural Chemistry and Environment 2016年第4期5卷 179-190页

作者： Timothy S. Goebel Robert J. Lascano Veronica acosta-Martinez USDA-ARS Wind Erosion and Water Conservation Unit Lubbock TX USA

The Conservation Reserve Program (CRP) is a USDA program introduced in 1985 to reduce soil erosion by increasing vegetative cover of highly erodible land. Participation in the CRP is done via contracts (10 - 15 years in length) and currently the total area of land under contract is set to decline as per the 2014 Farm Bill. The Texas High Plains (THP) leads the US with >900,000 ha enrolled in CRP. A potential long- term benefit of CRP is to increase soil organic matter and to improve soil structure leading to increased water infiltration. Our objective was to evaluate the feasibility of using stable isotopes of water to measure and compare infiltration of rain in land under CRP management to land under continuous dryland cotton in the THP. For this purpose we selected two sites, with soils in the Amarillo series, enrolled in CRP, one for 25 years and the second site for 22 years. Results from several rain events showed that stable isotopes of water are a method that can be used to evaluate the depth of rainwater infiltration for soils under CRP and dryland management.

关键词： Conservation Reserve Program Rain Infiltration Stable Isotopes Dryland Cotton

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Cover Crop and Irrigation Effects on Soil Microbial Communities and Enzymes in Semiarid Agroecosystems of the Central Great Plains of North America

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Pedosphere 2016年第2期26卷 192-205页

作者： Francisco J. CALDERON David NIELSEN Veronica acosta-MARTINEZ Merle F. VIGIL Drew LYON USDA-ARS Central Great Plains Research Station Akron CO 80720 USA USDA-ARS Cropping Systems Research Laboratory Wind Erosion and Water Conservation Unit Lubbock TX 79415 USA Department of Crop and Soil Sciences Washington State University Pullman WA 99164-6420 USA

Cover crops can have beneficial effects on soil microbiology by increasing carbon （C） supply, but these beneficial effects can be modulated by precipitation conditions. The objective of this study was to compare a fallow-winter wheat （Triticum aestivum L.） rotation to several cover crop-winter wheat rotations under rainfed and irrigated conditions in the semiarid US High Plains. Experiments were carried out at two sites, Sidney in Nebraska, and Akron in Colorado, USA, with three times of soil sampling in 2012--2013 at cover crop termination, wheat planting, and wheat maturity. The experiments included four single-species cover crops, a 10-species mixture, and a fallow treatment. The variables measured were soil C and nitrogen （N）, soil community structure by fatty acid methyl ester （FAME） profiles, and soil β-glucosidase,β-glucosaminidase, and phosphodiesterase activities. The fallow treatment, devoid of living plants, reduced the concentrations of most FAMEs at cover crop termination. The total FAME concentration was correlated with cover crop biomass （R = 0.62 at Sidney and 0.44 at Akron）. By the time of wheat planting, there was a beneficial effect of irrigation, which caused an increase in myeorrhizal and protozoan markers. At wheat maturity, the cover crop and irrigation effects on soil FAMEs had subsided, but irrigation had a positive effect on the β-glucosidase and phosphodiesterase activities at Akron, which was the drier of the two sites. Cover crops and irrigation were slow to impact soil C concentration. Our results show that cover crops had a short-lived effect on soil microbial communities in semiarid wheat-based rotations and irrigation could enhance soil enzyme activity. In the semiarid environment, longer time spans may have been needed to see beneficial effects of cover crops on soil microbial community structure, soil enzyme activities, and soil C sequestration.

关键词： crop rotation enzyme activity FAME profile fatty acid methyl ester winter wheat

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用共轭场匹配法补偿反射面天线表面畸变

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空天技术 1990年第5期 55-56页

作者： Roberto J. acosta 殷善贤

人们对补偿反射面表面畸变的可行性已进行了大量的研究。空间通信反射天线系统的性能(增益、副瓣电平、零点位置、波束宽度等)会随着由变化的阳光的热效应所引起的反射面表面畸变而变坏。本技术使辐射设计性能不受反射面表面上的热效应... 详细信息

人们对补偿反射面表面畸变的可行性已进行了大量的研究。空间通信反射天线系统的性能(增益、副瓣电平、零点位置、波束宽度等)会随着由变化的阳光的热效应所引起的反射面表面畸变而变坏。本技术使辐射设计性能不受反射面表面上的热效应的影响。单片微波集成电路(MMIC)的出现使得阵馈反射面系统的设计可以达到很大的自适应性,MMIC阵独立控制馈源阵的每个辐射单元的振幅和相位。在表面畸变时要维持设计辐射性能所需要的单元激励的获得是基于共轭场匹配技术的。文中假设已知畸变表面特征(X,Y,Z,一阶导数和二阶导数)。

关键词：反射器天线表面畸变天线辐射图匹配-补偿

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On-Line Photoinduced Fluorescence for Carbamazepine Determination after Multivariate Optimization

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American Journal of Analytical Chemistry 2019年第11期10卷 513-527页

作者： Cecilia Henestrosa Cecilia Peralta Leslie Aragó n Liliana FernÁ ndez Gimena acosta Área de Farmacotecnia Ética y Legislación FarmacÉutica San Luis Argentina Instituto de Química de San Luis (INQUISAL-CONICET) San Luis Argentina Área de Gestión en Calidad y Salud San Luis Argentina Área de Química Analítica Facultad de Química Bioquímica y Farmacia Universidad Nacional de San Luis Chacabuco y Pedernera San Luis Argentina

This work presents a simple and sensitive flow injection fluorimetric method for the determination of carbamazepine (CBZ) in pharmaceutical samples. It is based on the fluorescence signal measurement of the product generated by photoinduced (λex = 251 nm;λem = 434 nm) using a flow injection manifold containing an online homemade photoreactor. In order to optimize the experimental setup, the variable conditions were studied using a multivariate optimization method, thus finding the set of optimum parameters according to the evaluated responses (sensitivity and sampling frequency) and minimizing the number of experiments performed. Under optimal experimental conditions, linear relationship with good correlation coefficient (0.9956) was found between the fluorescence intensity and CBZ concentration in the range of 0.13 - 40 μg·mL-1. The limit of detection was 0.04 μg·mL-1. The precision of the method was satisfactory;the values of relative standard deviations were better than 4.36%. The proposed method was validated and successfully applied to the determination of CBZ in pharmaceuticals with good accuracy;being the recovery values from 89.45% - 112.20%.

关键词： Online Photoinduced Fluorescence Multivariate Optimization Carbamazepine Pharmaceutical Samples

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Key genes and drug delivery systems to improve the efficiency of chemotherapy

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Cancer Drug Resistance 2021年第1期4卷 163-191页

作者： Zally Torres-Martinez Yamixa Delgado Yancy Ferrer-acosta Ivette J Suarez-Arroyo Freisa M.Joaquin-Ovalle Louis J.Delinois Kai Griebenow Chemistry Department University of Puerto Rico-Rio Piedras campusSan JuanPR 00936USA Biochemistry&Pharmacology Department San Juan Bautista School of MedicineCaguasPR 00726USA Neuroscience Department Universidad Central del CaribeBayamonPR 00956USA Biochemistry Department Universidad Central del CaribeBayamonPR 00956USA

Cancer cells can develop resistance to anticancer drugs,thereby becoming tolerant to treatment through different *** biological mechanisms leading to the generation of anticancer treatment resistance include alterations in transmembrane proteins,DNA damage and repair mechanisms,alterations in target molecules,and genetic responses,among *** most common anti-cancer drugs reported to develop resistance to cancer cells include cisplatin,doxorubicin,paclitaxel,and *** anticancer drugs have different mechanisms of action,and specific cancer types can be affected by different *** development of drug resistance is a cellular response which uses differential gene expression,to enable adaptation and survival of the cell to diverse threatening environmental *** this review,we briefly look at the key regulatory genes,their expression,as well as the responses and regulation of cancer cells when exposed to anticancer drugs,along with the incorporation of alternative nanocarriers as treatments to overcome anticancer drug resistance.

关键词： Cancer resistance drug delivery systems resistance genes

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DISCRETIZATION AND BEST APPROXIMATION IN BESOV SPACES

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Analysis in Theory and Applications 1999年第2期15卷 22-35页

作者： J. M. Almira (1) F. Pérez acosta (1) 1. Departmento de Analisis Matematico Universidad de la Laguna 38271 La Laguna Tenerife Spain

In this paper we prove a theorem about existence of best approximation in a class of spaces involving Besov spaces, via a discretization technique. It is a consequence of this theorem that rational functions and exponencial sums are proximinal subsets of B ∞,q a (π). It is also proved the proximinality of R m n [a, b] in B p,q a (π) for arbitrary p,q and a.

关键词： XL EN DISCRETIZATION AND BEST APPROXIMATION IN BESOV SPACES

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Synthesis of Novel Hexathiolated Squalene and Its Thiol-Ene Photopolymerization with Unsaturated Monomers

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Green and Sustainable Chemistry 2012年第2期2卷 62-70页

作者： Ricardo acosta Ortiz Ena Adeligna Obregón Blandón Ramiro Guerrero Santos Centro de Investigación en Química Aplicada Saltillo México Universidad Nacional de Ingeniería Avenida Universitaria Managua Nicaragua

In this work is described the synthesis of a multifunctional thiolated squalene. Thiol-ene coupling reactions were employed to functionalize the six double bonds of squalene, using thiolacetic acid. Hydrolysis of the resulting thioacetates, rendered the corresponding hexathiolated squalene SQ6SH. This compound was further photopolymerized separately with triallyl cyanurate, pentaerythritol triacrylate and diethyleneglycol divinyl ether. Real Time FTIR kinetics revealed that homopolymerization of the ene monomers took place in addition to the thiol-ene photopolymerization. Flexible films were obtained when SQ6SH was photopolymerized in bulk with the above mentioned unsaturated monomers.

关键词： Squalene Thiol-Ene Photopolymerization Biomaterials Kinetics

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Mathematical Model to Elaborate the Table of Thermodynamic Properties

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Journal of Applied Mathematics and Physics 2022年第6期10卷 1951-1967页

作者： Debrayan Bravo Hidalgo Liliana Del Carmen Morillo acosta Nancy Del Rocio Flores Hinojosa Sharing Knowledge Group (SKG) Quito Ecuador Administrative Sciences Department Universidad Central del Ecuador Quito Ecuador

Purpose: The aim of this scientific contribution is to show the potential that integral calculus has offered to the analysis of thermodynamic processes. Method: Application of Integral Calculus. In this context, the document covers the theoretical principles of integral calculus, such as Theoretical framework and background, Geometric interpretation of the primitive, Primitive existence theorem. Results: Integral calculus and generalized thermodynamic models, and their applications in various thermodynamic analysis contacts such as the Generalized Enthalpy Model, the Generalized Entropy Model, and the Generalized Model applied to gas mixtures and the General Model to elaborate the properties table. Conclusion: The mathematical analysis developed in this document is very useful in engineering and applied physics environments, a fact that supports its common pedagogical practice in university institutions.

关键词： Equations Curves of Thermal Processes Thermodynamic Laws Physics-Mathematics Energy

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