221 research outputs found

    Mountain Pygmies of Western New Guinea: A Morphological and Molecular Approach

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    The presence of pygmy or pygmoid groups among New Guinea populations has been the object of scientific interest since the end of the nineteenth century. Morphological and molecular data are used here to study western New Guinea population variability, focusing in particular on two pygmoid groups living in the eastern fringe highlands of Papua: the Una and the Ketengban. Various kinds of anthropometric data are examined, as well as height, weight, and body mass index, to carry out comparisons with nearby ethnic groups living in the highland and lowland regions. The Ketengban data were also compared with other data recorded 20 years before. The results of previous research on the sequencing of the mitochondrial DNA hypervariable segment 1 region and nuclear DNA nonrecombining Y-chromosome polymorphisms are presented. Both morphological and molecular studies involve adult subjects of both genders, representative of the same ethnic groups and/ or geographic regions. The pygmoid groups turn out to be significantly different from all other study groups, due to their small size, as confirmed by analysis of variance, although significant height and weight increments are observed with respect to those previously recorded. However, putative neutral genetic variation estimated from mitochondrial DNA and Y-chromosome markers support a recent shared common history between these pygmoid populations and the other central Papua groups (except for the Dani-Lani). These findings suggest that the short-stature phenotype is an independent secondary adaptation, possibly driven by an iodine-deficient environment, which leaves the potential for further investigations

    Inmobilization of Zn(II) in Portland cement pastes. Determination of microstructure and leaching performance

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    The aim of this paper is to study the solidification/ stabilization potential of cementitious matrices on the immobilization of Zn(II) before its disposal into the environment by determining the mechanisms of interaction between the Zn(II) ions and the binder. The results of structural and mineralogical characterization of cement pastes formed with different amounts of immobilized Zn(II) ions are presented and the study includes results from thermogravimetric analysis (TG), scanning electron microscopy, X-ray diffraction, and leaching performance. Zn(II) ions delay the hydration reaction of Portland cement due to the formation of mainly CaZn2(OH)6 2H2O , as well as Zn5(CO3)2(OH)6, Zn(OH)2, and ZnCO3 in minor proportion. Correlations between total mass loss in TG analysis and leached Zn(II) ions in long-term curing pastes have been obtained. This result is important because in a preliminary approach from a TG on an early-aged cement paste containing Zn(II), it could be possible to perform an estimation of the amount of Zn(II) ions that could be leached, thus avoiding costly and time-consuming tests.Mellado Romero, AM.; Borrachero Rosado, MV.; Soriano Martinez, L.; Paya Bernabeu, JJ.; Monzó Balbuena, JM. (2013). Inmobilization of Zn(II) in Portland cement pastes. Determination of microstructure and leaching performance. Journal of Thermal Analysis and Calorimetry. 112(3):1377-1389. doi:10.1007/s10973-012-2705-8S137713891123Mojumdar SC, Sain M, Prasad RC, Sun L, Venart JES. Selected thermoanalytical methods and their applications from medicine to construction, Part I. J Therm Anal Calorim. 2007;90:653–62.Perraki M, Perraki T, Kolovos K, Tsivilis S, Kakali G. Secondary raw materials in cement industry. Evaluation of their effect on the sintering and hydration processes by thermal analysis. J Therm Anal Calorim. 2002;70:143–50.Neves A, Dias Toledo R, de Moraes Rego E, Dweck J. Early stages hydration of high initial strength Portland cement. Part I. Thermogravimetric analysis on calcined mass basis. J Therm Anal Calorim. 2012;108:725–31. doi: 10.1007/s10973-012-2256-z .Balek V, Bydžovský J, Dufka A, Drochytka R, Beckman IN. Use of emanation thermal analysis to characterize microstructure development during Portland cement hydration. J Therm Anal Calorim. 2012. doi: 10.1007/s10973-012-2314-6 .Zhang Q, Ye G. Dehydration kinetics of Portland cement paste at high temperature. J Therm Anal Calorim. 2012. doi: 10.1007/s10973-012-2303-9 .Menéndez E, Vega L, Andrade C. Use of decomposition of portlandite in concrete fire as indicator of temperature progression into the material. Application to fire-affected builds. J Therm Anal Calorim. 2012. doi: 10.1007/s10973-011-2159-4 .Galan I, Andrade C, Castellote M. Thermogravimetrical analysis for monitoring carbonation of cementitious materials. Uptake of CO2 and deepening in C–S–H knowledge. J Therm Anal Calorim. 2012. doi: 10.1007/s10973-012-2466-4 .Batchelor B. Overview of waste stabilization with cement. Waste Manag (Oxford). 2006;26:689–98.Gineys N, Aouad G, Damidot D. Managing trace elements in Portland cement-Part I: interactions between cement paste and heavy metals added during mixing as soluble salts. Cem Concr Compos. 2010;32:563–70.Erdem M, Özverdi A. Environmental risk assessment and stabilization/solidification of zinc extraction residue: II. Stabilization/solidification. Hydrometallurgy. 2011;105:270–6.Nocuń-Wczelik W, Małolepszy J. Application of calorimetry in studies of the immobilization of heavy metals in cementitious materials. Thermochim Acta. 1995;269(270):613–9.Dweck J, Buchler PM, Cartledge FK. The effect of different bentonites on cement hydration during solidification/stabilization of tannery wastes. J Therm Anal Calorim. 2001;64:1011–6.Melchert MBM, Viana MM, Lemos MS, Dweck J, Buchler PM. Simultaneous solidification of two catalyst wastes and their effect on the early stages of cement hydration. J Therm Anal Calorim. 2011;105:625–33.Vessalas K, Thomas PS, Ray AS, Guerbois JP, Joyce P, Haggman J. Pozzolanic reactivity of the supplementary cementitious material pitchstone fines by thermogravimetric analysis. J Therm Anal Calorim. 2009;97:71–6.Tommaseo CE, Kersten M. Aqueous solubility diagrams for cementitious waste stabilization systems. 3. Mechanism of zinc immobilization by calcium silicate hydrate. Environ Sci Technol. 2002;36:2919–25.Peyronnard O, et al. Study of mineralogy and leaching behavior of stabilized/solidified sludge using differential acid neutralization analysis. Cem Conc Res. 2009. doi: 10.1016/j.cemconres.2009.03.016 .Moulin I, et al. Lead, zinc and chromium (III) and (VI) speciation in hydrated cement phases. International conference on the science and engineering of recycling for environmental protection, waste materials in construction (WASCON 2000), Harrogate, England, 2000, pp. 269–280.Ziegler F, Gieré R, Johnson CA. Sorption mechanisms of zinc to calcium silicate hydrate: sorption and microscopic investigations. Environ Sci Technol. 2001;35:4556–61.Qiao XC, Poon CS, Cheeseman CR. Investigation into the stabilization/solidification performance of Portland cement through cement clinker phases. J Hazard Mater. 2007;B139:238–43.Chen QY, et al. Immobilisation of heavy metal in cement-based solidification/stabilisation: a review. Waste Manag (Oxford). 2009;29:390–403.Chen QY, et al. Characterisation of products of tricalcium silicate hydration in the presence of heavy metals. J Hazard Mater. 2007;147:817–25.Fernandez-Olmo I, Chacon E, Irabien A. Influence of lead, zinc, iron (III) and chromium (III) oxides on the setting time and strength development of Portland cement. Cem Concr Res. 2001;31:1213–9.Fernandez-Olmo I, Chacon E, Irabien A. Leaching behavior of lead, chromium (III) and zinc in cement/metal oxides systems. ASCE J Environ Eng. 2003;129:532–8.Cappuyns V, Swennenb R. The application of pHstat leaching tests to assess the pH-dependent release of trace metals from soils, sediments and waste materials. J Hazard Mater. 2008;158:185–95.Payá J, Monzó J, Borrachero MV, Velázquez S. Evaluation of the pozzolanic activity of fluid catalytic cracking catalyst residue (FC3R): thermogravimetric analysis studies on FC3R-Portland cement pastes. Cem Concr Res. 2003;33:603–9.Wang S, Yang Z, Zeng L. Study of calcium zincate synthesized by solid-phase synthesis method without strong alkali. Mater Chem Phys. 2008;112:603–6.Stumm A, et al. Incorporation of zinc into calcium silicate hydrates, Part I: formation of C–S–H(I) with C/S = 2/3 and its isochemical counterpart gyrolite. Cem Concr Res. 2005;35:1665–75.Stephan D, Mallmann R, Knöfel D, Härdtl R. High intakes of Cr, Ni, and Zn in clinker, Part II. Influence on the hydration properties. Cem Concr Res. 1999;29:1959–67.Liu Y, et al. Thermal decomposition of basic zinc carbonate in nitrogen atmosphere. Thermochim Acta. 2004;414:121–3.Wahab R, et al. Synthesis and characterization of hydrozincite and its conversion into zinc oxide nanoparticles. J Alloy Compd. 2008;461:66–71.Hatakeyama T, Liu Z. Handbook of thermal analysis. New Yok: Wiley; 2000

    Il processo minorile e il diritto di difesa

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    La domanda d'arbitrato

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