José Maria Blázquez Martínez, Arte y religión en el Mediterráneo antiguo, 2008 [Reseña]

Alvarez Melero Anthony. José Maria Blázquez Martínez, Arte y religión en el Mediterráneo antiguo, 2008. In: L'antiquité classique, Tome 78, 2009. p. 614

Newtonian M(atrix) Cosmology

A Newtonian matrix cosmology, correspoding to the BFSS model of eleven-dimensional M-theory in the IMF as a (0+1) M(atrix) model is constructed. Interesting new results are obtained, such as the existence of (much sought for in the past) static solutions. The possible interpretation of the off-diagonal entries as a background geometry is also briefly discussed.Comment: 9 pages, Latex2

The analytic index for a family of Dirac-Ramond operators

We derive a cohomological formula for the analytic index of the Dirac-Ramond operator and we exhibit its modular properties.Comment: 6 page

Vibrational Analysis Of Amorphous Carbon-nitrogen Alloys By 15n And D Isotopic Substitution

The origin of the vibrational modes of a-CNx alloys is investigated by infrared (ir) and Raman spectroscopies. Isotopic substitution of 15N and D is used in the identification of vibration modes. In nonhydrogenated materials containing low nitrogen concentration (≤20 at. %), the ir and Raman spectra are not equivalent. Above this concentration (up to ∼30 at. %), the spectra became very similar to each other. On the contrary, for a suitable hydrogen content the spectra are quite similar, independently of the range of nitrogen concentrations studied. Quantum chemical Parametric Method 3 calculations are performed to obtain the frequencies and intensities of the ir active vibrations of organic molecules and large carbon-nitrogen clusters. These results are used to help in the identification of the features observed in the ir spectra. The importance of both the promotion of bond dipoles and symmetry breaking by nitrogen in the ir spectra is established. ©2000 The American Physical Society.61210831087Fang, P.H., (1995) J. Mater. Sci. Lett., 14, p. 536Franceschini, D.F., Achete, C.A., Freire Jr., F.I., (1992) Appl. Phys. Lett., 60, p. 3229Jones, D.I., Stewart, A.D., (1982) Philos. Mag. B, 46, p. 423Chen, L.C., Lu, T.R., Cuo, C.T., Bhusari, D.M., Wu, J.J., Chen, K.H., Chen, T.M., (1998) Appl. Phys. Lett., 72, p. 3449Liu, A., Cohen, L., (1989) Science, 245, p. 841Kaufman, J.H., Metin, S., Saperstein, D.D., (1989) Phys. Rev. B, 39, p. 13053Souto, S., Alvarez, F., (1997) Appl. Phys. Lett., 70, p. 1539Hammer, P., Victoria, N.M., Alvarez, F., (1998) J. Vac. Sci. Technol. A, 16, p. 2941Alvarez, F., Victoria, N.M., Hammer, P., Freire Jr., F.L., Dos Santos, M.C., (1998) Appl. Phys. Lett., 73, p. 1065Alvarez, F., Dos Santos, M.C., Hammer, P., (1998) Appl. Phys. Lett., 73, p. 3521Souto, S., Pickholz, M., Dos Santos, M.C., Alvarez, F., (1998) Phys. Rev. B, 57, p. 2536Dos Santos, M.C., Alvarez, F., (1998) Phys. Rev. B, 58, p. 13918Stewart, J.J.P., (1989) J. Comput. Chem., 10, p. 209(1995) SPARTAN, Package V. 5, , Wavefunction, Inc(1996) HYPERCHEM, Version 5, , Hypercube, IncLey, L., (1984) Topics in Applied Physics, 56. , The Physics of Hydrogenated Amorphous Silicon II, edited by J. D. Joannopoulos and G. Lucousky, Springer-Verlag, BerlinSubramanian, V., Chitra, K., Venkatesh, K., Sanker, S., Ramasami, T., (1997) Chem. Phys. Lett., 264, p. 92Shinohara, Y., Saito, R., Kimura, T., Dresselhaus, G., Dresselhaus, M.S., (1994) Chem. Phys. Lett., 227, p. 365Borisenko, V.E., Baturin, A.V., Przeslawka, M., Koll, A., (1997) J. Mol. Struct., 407, p. 53Robertson, J., (1991) Prog. Solid State Chem., 21, p. 19

Effect of pH, temperature ,conductivity and sediment size on thorium activities along Jucar River (Spain)

[EN] A study is presented on the distribution of thorium and radium isotopes in sediments, suspended matter and water collected along Jucar river (East of Spain), using low-level alpha-spectrometry. The first aim of this work is to study the thorium and radium activity in water, sediment and suspended matter and their dependence on pH, temperature, conductivity and sediment sizes along Jucar river. The analysis of activity variation with these parameters will provide information about the dynamics of these radionuclides in rivers. The values obtained for the distribution factors between suspended matter and water (K-d) are also discussed.Sanchez, F.; Rodríguez-Álvarez, M. (1999). Effect of pH, temperature ,conductivity and sediment size on thorium activities along Jucar River (Spain). Journal of Radioanalytical and Nuclear Chemistry. 242(3):671-681. doi:10.1007/BF02347378S6716812423M. J. Rodríguez-Alvarez, F. Sánchez, J. Radioanal. Nucl. Chem., 191 (1995) 3.M. J. Rodríguez-Alvarez, F. Sánchez, E. Navarro, Proc. 3rd Intern. Summer School, Huelva Spain,M. García-León andG. Madurga (Eds), World Scientific, Singapore, 1994, p. 549.M. J. Rodríguez-Alvarez, Medidas de Uranio, Torio y Radio en Muestras Ambientales por Espectrometría alfa. Aplicación a un Modelo Unidimensional de Transporte de Radionúclidos en el Río Júcar. PhD Thesis, Universidad de Valencia, Spain, 1998 (in Spanish).M. J. Rodríguez-Alvarez, F. Sánchez, J. Radioanal. Nucl. Chem., to be published.M. J. Rodríguez-Alvarez, F. Sánchez, J. Radioanal. Nucl. Chem., 190 (1995) 113.Uranium Disequilibrium Series. Applications to Environmental Problems,M. Ivanovich andR. S. Harmon (Eds), Clarendon Press, Oxford, 1992.A. Martinez-Aguirre, M. García-León, J. Radioanal. Nucl. Chem., 155 (1991) 97.R. Periañez, A. Martinez-Aguirre, J. Environ. Radiact., 35 (1997) No. 3, 281.P. Beneš, P. Picat, M. Černík, J. M. Quinault, J. Radioanal. Nucl. Chem., 159 (1992) 175.P. Beneš, M. Černík, J. Radioanal. Nucl. Chem., 159 (1992) 187.N. A. Talvitie, Anal. Chem., 44 (1972) 280.R. García-Tenorio, M. García-León, M. Madurga, C. Piazza, Anal. Física B, 82 (1986) 238.L. Hallstadius, Nucl. Instrum. Meth. Phys. Res. 223 (1984) 266.G. J. Hancock, P. Martin, Appl. Radiation Isotopes, 40 (1989) 63.USEPA, Potential Health and Environmental Hazard of Uranium Mine Wastes, EPA 520/1-83-007, U.S. Environmental Protection Agency, Washington, 1983.P. Beneš, Physico-chemical Forms and Migration in Continental Waters of Radium from Uranium Mining and Milling, in: Environmental Migration of Long-lived Radionuclides, IAEA, Vienna, 1982, p. 3.F. Šebesta, Environ. Sci. Technol., 15 (1981) 71.P. Beneš, Water Res., 17 (1983) 619.P. Beneš, P. Strejc, J. Radioanal. Nucl. Chem., 99 (1986) 407.T. H. Sibley, C. Myttenaere, Application of Distribution Coefficients to Radiological Assesment Models, Elsevier Applied Science Publishers, 1986.J. E. Till, H. R. Meyer, Radiological Assessment. A Textbook on Environmental Dose Analysis, NUREG/CR-3332, Washington, D.C., 1983.Sedimentk d and Concentration Factors for Radionuclides in Marine Environment, IAEA Technical Report Series, No. 247, 1985

Thermal stability of the cu-ceo2 interface on silica and alumina, and its relation with activity in the oxidation reaction of co and the decomposition of n2o

Indexación: Scopus; Scielo.The effect of the support on the formation of the Cu-CeO2 interface and its thermal stability after calcination at 500, 700 and 900 °C is studied. The supports used are SiO2, because of its inert character, and Al2O3, because it can interact with the Cu and Ce species on the surface. The catalysts were characterized by BET, XRD, UV-vis DRS, and TPR with H2. The catalytic activity in the CO oxidation reactions with O2 at low temperature and the decomposition of N2O were selected to visualize the effect of temperature on the concentration of Cu-CeO2 interfacial sites. The results show that at a calcination temperature of 500 °C the formation of the Cu-CeO2 interface is favored over the SiO2 support. However, the stability of the Cu-CeO2 interface on SiO2 is much lower than on Al2O3, causing a substantial decrease of the interfacial sites calcining at 700 °C, and segregation of the Cu and Ce species on the surface of the silica, with complete loss of the catalytic activity in both reactions when calcining at 900 °C. In contrast, on alumina the Cu-CeO2 interface is more stable and presents a significant catalytic activity in both reactions, even when calcining at 900 °C. The characterization results show that the sintering process of Cu species and CeO2 particles is less on the alumina support due to the greater interaction of the Cu and Ce with this support. © 2018 Sociedad Chilena de Quimica.all rights reserved.https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0717-97072018000304102&lng=en&nrm=iso&tlng=e