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Allophane as a Nanotechnological Additive in Masonry Materials to Increase Resistance and Waterproofing

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Advances in Materials Physics and Chemistry 2024年第8期14卷 196-212页

作者： Edward H. Jiménez Joao Rivera Juan H. Villalba Paola E. vera Marlon Cuenca Belén Granja Javier Fuentes Sandra Gavilanes Daniel Hidalgo Fernando Garcia Jose Bermudez Washington Ruiz Alexis Martial Debut Facultad de Ingeniera Qumica Universidad Central del Ecuador Quito Ecuador Facultad de Arquitectura y Urbanismo Universidad Central del Ecuador Quito Ecuador Nanomaterials Characterization Laboratory Universidad de las Fuerzas Armadas ESPE Sangolqu Ecuador

The constant need for high-strength materials in the construction industry promotes the research of additives that improve the properties of masonry materials. The use of allophane as an additive in concrete and mortar mixtures was implemented to improve their strength and waterproofing, respectively, using compression and water absorption tests according to their corresponding standards (ASTM C1231, ASTM D2938, and ASTM C1585). The samples were evaluated at different concentrations and curing ages. In addition, different sand/cement ratios were considered for the mortar. The results revealed that there was a 9.4% increase in compressive strength in concrete and a 23.7% reduction in water absorption in mortar for the 5:1 ratio. These changes would be the result of the interaction of the nanoporous additive in the atomic crystal structure of the material demonstrating the nanotechnological nature of allophane.

关键词： Allophane Nano Additive Strength Impermeability Concrete Mortar

Sap flow rates of Minquartia guianensis in central Amazonia during the prolonged dry season of 2015–2016

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Journal of Forestry Research 2021年第5期32卷 2067-2076页

作者： Saul A.Antezana-vera Ricardo A.Marenco Botany Graduate Program Instituto Nacional de Pesquisas da Amazônia-INPAAvenida AndréAraújo2936ManausAM 69067-375Brazil Tree Ecophysiology LaboratoryInstituto Nacional de Pesquisas da Amazônia-INPAAvenida AndréAraújo2936ManausAM 69067-375Brazil

Minquartia guianensis *** a slow-growing species with several *** the juvenile state,it is well-adapted to low light conditions of the forest ***,it is still unknown how climate variability affects transpiration of this species,particularly under drought *** this study,we aimed to assess the effect of climatic variability on sap flow rates(SFR).SFR and radial growth were measured in six trees(14-50 cm diameter)in 2015 and ***(precipitation,irradiance,relative humidity and temperature)and soil water content(SWC)data were also *** tended to increase in the dry season,with a negative relationship between SFR and SWC and precipitation(p<0.001),while there was a positive association between radial growth and monthly precipitation(p=0.004).Irradiance and temperature were the environmental factors more closely correlated with SFR during daytime(p<0.001),whereas relative humidity and vapor pressure deficit were the most important factors at night(p<0.001).Although negative SFR were sometimes recorded at night,the mean nocturnal sap flow was positive and across trees the nighttime sap flow accounted for 12.5%of the total daily sap *** transpiration during the dry season suggests that the root system of Minquartia was able to extract water from deep soil *** results widen our understanding of the ecophysiology of Amazonian trees under drought and provide further insight into the potential effect of the forecasted decline in precipitation in the Amazon region.

关键词： Reverse sap flow Soil water content Transpiration Tree growth

Pre-emergence herbicides affect seedling emergence of tropical forest tree species

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Journal of Forestry Research 2017年第4期28卷 733-739页

作者： Diego Cerveira de Souza vera Lex Engel Forest Science Department Agronomic Sciences College-FCASao Paulo State University – UNESPP.O. Box 237BotucatuSP 18603-970Brazil

Testing techniques to reduce weed infestation is a crucial step in developing direct tree seeding systems. The use of pre-emergence herbicides may be an alternative to manual weeding techniques, but so far, information on how they affect the seeds of native tree species is scarce. We established a greenhouse experiment to evaluate the effects of four pre-emergence herbicides (atrazine, diuron, isoxaflutole and oxyfluorfen) on weed suppression and seedling emergence and early growth of seven tropical forest tree species (Annona coriacea Mart., Citharexylum myrianthum Cham., Cordia ecalyculata Vell., Peltophorum dubium (Spreng.) Taub., Psidium guajava L., Pterogyne nitens Tul. and Schinus terebinthifolia Raddi). The experimental design was a randomized complete block design with five treatments and five replicates. The treatments consisted of a single dose of each pre-emergence herbicide and a control. Throughout the 60 days after sowing we evaluated weed cover and seedling emergence and early growth of tree species. Overall, our results suggest that all tested herbicides reduced weed cover; however, they also negatively affected tree species seedling emergence. Of the four herbicides tested, atrazine and diuron showed the greatest effects on tree seedling emergence, oxyfluorfen was least aggressive towards native species and isoxaflutole was most effective in weed control. Native tree species varied in their responses to herbicides, indicating that future experiments should increase the number of species tested as well as investigate how seed traits can affect the species responses to different herbicides.

关键词： Pre-emergence herbicides Weed control Direct seeding Seedling emergence Tropical seasonal forests

Same or different?Abstract relational concept use in juvenile bamboo sharks and Malawi cichlids

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Current Zoology 2021年第3期67卷 279-292页

作者： Theodora Fuss Leonie John vera Schluessel Institute of Zoology Rheinische Friedrich-Wilhelms-University BonnMeckenheimer Allee 169Bonn53115Germany

Sorting objects and events into categories and concepts is an important cognitive prerequisite that spares an individual the learning of every object or situation encountered in its daily ***,specific items are classified in general groups that allow fast responses to novel *** present study assessed whether bamboo sharks Chiloscyllium griseum and Malawi cichlids Pseudotropheus zebra can distinguish sets of stimuli(each stimulus consisting of two abstract,geometric objects)that meet two conceptual preconditions,i.e.,(1)"sameness"versus"difference"and(2)a certain spatial arrangement of both *** two alternative forced choice experiments,individuals were first trained to choose two different,vertically arranged objects from two different but horizontally arranged *** discriminations were followed by extensive transfer test *** tests using stimuli consisting of(a)black and gray circles and(b)squares with novel geometric patterns provided conflicting information with respect to the learnt rule"choose two different,vertically arranged objects",thereby investigating(1)the individuals'ability to transfer previously gained knowledge to novel stimuli and(2)the abstract relational concept(s)or rule(s)applied to categorize these novel *** results suggest that the level of processing and usage of both abstract concepts differed considerably between bamboo sharks and Malawi *** sharks seemed to combine both concepts-although not with equal but hierarchical prominence-pointing to advanced cognitive ***,Malawi cichlids had difficulties in discriminating between symbols and failed to apply the acquired training knowledge on new sets of geometric and,in particular,gray-level transfer stimuli.

关键词： visual concept learning spatial arrangement relational abstract concept Malawi cichlid bamboo shark

The method of residual‑based bootstrap averaging of the forecast ensemble

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Financial Innovation 2023年第1期9卷 991-1002页

作者： vera Ivanyuk Department of Data Analysis and Machine Learning Financial University49 Leningradsky ProspektMoscowRussia 125993

This paper presents an optimization approach—residual-based bootstrap averaging(RBBA)—for different types of forecast *** traditional residual-mean-square-error-based ensemble forecast averaging approaches,the RBBA method attempts to find optimal forecast weights in an ensemble and allows for their combi-nation into the most effective additive *** the RBBA method,all the different types of forecasts obtain the optimal weights for ensemble residuals that are statisti-cally optimal in terms of the fitness function of the *** studies have been conducted to demonstrate why and how the RBBA method *** experi-mental results based on the real-world time series of contemporary stock exchanges show that the RBBA method can produce ensemble forecasts with good generalization ability.

关键词： Forecast ensembles Time series Artificial neural networks

Linking plant metabolism and immunity through methionine biosynthesis

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Molecular Plant 2022年第1期15卷 6-8页

作者： Francisco Escaray Amelia Felipo-Benavent Pablo vera Instituto de Biología Molecular y Celular de Plantas Universidad Politécnica de Valencia-C.S.I.CCiudad Politécnica de la InnovaciónEdificio 8EIngeniero Fausto Elios/n46022 ValenciaSpain

Plants respond to pathogenic cues with a transcriptional reprog-ramming that leads to de novo production of defense-related pro-teins and a huge variety of secondary metabolites(e.g.,phyto-alexins,phenolics,etc.).Activation of these host defenses,which contribute to halt the intruder as part of the resistance,im-plies an increased demand for metabolic energy and carbon skel-etons derived from primary metabolism(Bolton,2009).

关键词： metabolism immunity Bolton

IAS/IFRS and financial reporting quality:Lessons from the European experience

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China Journal of Accounting Research 2013年第4期6卷 247-263页

作者： vera Palea Department of Economics and Statistics "Cognetti de Martiis" University of Torino

This paper discusses the effects of the adoption of IAS/IFRS in Europe on the quality of financial *** doing so,it adopts the perspective of stock market investors and focuses on value-relevance *** adoption of IAS/IFRS in Europe is an example of accounting standardization among countries with different institutional frameworks and enforcement *** allows investigating whether,and to what extent,accounting regulation per se can affect the quality of financial reporting and leads to convergence in financial *** is a key issue for standard setting purposes as IAS/IFRS have been adopted in very diverse countries all over the world,and many others are likely to adopt them in the near future.

关键词： Financial reporting quality IAS/IFRS Value-relevance European Regulation 1606/2002

Role of Osteoprotegerin and Receptor Activator of Nuclear Factor-kB Ligand in Bone Loss Related to Advanced Chronic Obstructive Pulmonary Disease

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Chinese Medical Journal 2016年第14期129卷 1696-1703页

作者： Ludmila Ugay Evgenia Kochetkova vera Nevzorova Yuliya Maistrovskaia Departement of Pulmonology Central Scientific Research Laboratory Pacific State Medical University Vladivostok 690950 Russian Federation

Background： Osteoporosis is a common complication of chronic obstructive pulmonary disease （COPD）. Recent clinical and biological researches have increasingly delineated the biomolecular pathways of bone metabolism regulation in COPD. We extended this work by examining the specific association and potential contribution of the osteoprotegerin （OPG）/receptor activator of nuclear factor-riB ligand （RANKL） axis to the pathogenesis of osteoporosis in advanced COPD. The aim of this study was to assess the relationships of serum OPG, RANKL, and tumor necrosis factor-alpha （TNF-a） with bone turnover in men with very severe COPD. Methods： Pulmonary function, T-score at the lumbar spine （LS） and femoral neck （FN）, serum OPG, RANKL, soluble receptor of tumor necrosis factor-alpha-1 and 11 （sTNFR-I, sTNFR-II）, osteocalcin （OC）, and β-CrossLaps （βCL） levels were measured in 45 men with very severe stage COPD and 36 male non-COPD volunteers. COPD patients and healthy controls were compared using all independent t-test and Mann-Whitney U-test. The Pearson coefficient was used to assess the relationships between variables. Results： OPG and OC were lower in male COPD patients than in control subjects whereas RANKL, serum ~CL, TN F-o~, and its receptors were higher. OPG directly correlated with forced expiratory volume in I s （FEVI） % predicted （r = 0.46, P 〈 0.005）, OC （r= 0.34, P 〈 0.05）, LS （I.= 0.56, P 〈 0.001 ）, and FN T-score （r= 0.47, P 〈 0.01 ）. In contrast, serum RANKL inversely associated with LS and FN T-score （r = -0.62, P 〈 0.001 and r = -0.48, P 〈 0.001 ） but directly correlated with [3CL （r = 0.48, P 〈 0.001 ）. In addition, OPG was inversely correlated with RANKL （r = -0.39, P 〈 0.01 ）, TNF-a （r = -0.56, P 〈 0.001 ）, and sTNFR-I （r = -0.40, P 〈 0.01 ）. Conelusion： Our results suggest that serum OPG and RANKL levels are inversely associated with bone loss in men with advanced stage COPD.

关键词： Chronic Obstructive Puhnonary Disease Osteoporosis Osteoprotegerin Receptor Activator of Nuclear Factor-KBLigand Tumor Necrosis Factor Receptors: Tumor Necrosis Factor-alpha

Effect of poly(3-hydroxyalkanoates) as natural polymers on mesenchymal stem cells

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World Journal of Stem Cells 2019年第10期11卷 764-786页

作者： vera Voinova Garina Bonartseva Anton Bonartsev Faculty of Biology M.V.Lomonosov Moscow State UniversityMoscow 119234Russia A.N.Bach Institute of Biochemistry Research Center of Biotechnology of the Russian Academy of SciencesMoscow 119071Russia

Mesenchymal stem cells(MSCs)are stromal multipotent stem cells that can differentiate into multiple cell types,including fibroblasts,osteoblasts,chondrocytes,adipocytes,and myoblasts,thus allowing them to contribute to the regeneration of various tissues,especially bone *** are now considered one of the most promising cell types in the field of tissue *** petri dish-based culture of MSCs generate heterogeneity,which leads to inconsistent efficacy of MSC *** and biocompatible polymers,poly(3-hydroxyalkanoates)(PHAs),are actively used for the manufacture of scaffolds that serve as carriers for MSC *** growth and differentiation of MSCs grown on PHA scaffolds depend on the physicochemical properties of the polymers,the 3D and surface microstructure of the scaffolds,and the biological activity of PHAs,which was discovered in a series of *** mechanisms of the biological activity of PHAs in relation to MSCs remain insufficiently *** suggest that this effect on MSCs could be associated with the natural properties of bacteria-derived PHAs,especially the most widespread representative poly(3-hydroxybutyrate)(PHB).This biopolymer is present in the bacteria of mammalian microbiota,whereas endogenous poly(3-hydroxybutyrate)is found in mammalian *** possible association of PHA effects on MSCs with various biological functions of poly(3-hydroxybutyrate)in bacteria and eukaryotes,including in humans,is discussed in this paper.

关键词： Mesenchymal stem cells Polyhydroxyalkanoates Poly(3-hydroxybutyrate) Tissue engineering Differentiation Natural functions Microbiota Bone Intestine