Proposal of a new erythemal UV radiation amplification factor

International audienceThis work is aimed to propose a natural expansion of radiation amplification factor (RAF) for erythemal irradiance to consider all solar zenith angles cases together. In this direction, the article analyzes the relationship between measurements of UV erythemal radiation (UVER) recorded at Badajoz (Spain) and the total ozone column estimated by the instrument TOMS/NASA for that location during the period February 2001?December 2005. The new RAF parameter is formulated by power equation using slant ozone and UVER atmospheric transmissivity values. Thus, reliable values of this parameter have been reported. These values could serve as a new relevant index for comparison with other studies and model's result. The new RAF is calculated with measurements recorded during completely clear cases using clearness index values higher than 0.75. The RAF value was 1.35±0.01, it is to say, when the slant ozone amount decreases 1% at Badajoz, UVER atmospheric transmissivity values and, therefore, UVER surface values approximately increase 1.35%. This result emphasizes the interest of measuring and monitoring simultaneous measurements of UV radiation and stratospheric ozone even for mid-latitudes. The influence of total ozone amount and cloudiness changes on new RAF values is analyzed. Cloud-free conditions allow to study the ozone influences while cloud effects are analyzed with all data by means of monthly average of slant ozone and UVER atmospheric transmissivities values

Passivity Breakdown of Titanium in LiBr solutions

The passive behavior of titanium and its susceptibility to undergo localized attack in different LiBr solutions at 25 degrees C have been investigated using different electrochemical techniques: potentiodynamic polarization curves, potentiostatic passivation tests, EIS measurements and Mott-Schottky analysis. In low and moderately concentrated LiBr solutions, the breakdown potential E-b decreased with increasing bromide concentrations, while in highly concentrated LiBr solutions, E-b increased with increasing LiBr concentration. In the most concentrated LiBr solution (11.42M) Ti did not undergo passivity breakdown even at 9 V-Ag/AgCl. This observation can be explained by a a decrease in the activity of water in highly concentrated LiBr solutions. (C) 2013 The Electrochemical Society.We wish express our gratitude to the Ministerio de Ciencia e Innovacion (Project CTQ2009-07518), and to Dr. M. Asuncion Jaime. for her translation assistance.Fernández Domene, RM.; Blasco-Tamarit, E.; García-García, D.; García Antón, J. (2014). Passivity Breakdown of Titanium in LiBr solutions. Journal of The Electrochemical Society. 161(1):25-35. https://doi.org/10.1149/2.035401jesS25351611Been J. Grauman J. S. , in: Uhlig's Corrosion Handbook, 2nd ed., Winston Revie R. (ed.), 863-885, Wiley Interscience, New York (2000).Blasco-Tamarit, E., Igual-Muñoz, A., García Antón, J., & García-García, D. (2007). Corrosion behaviour and galvanic coupling of titanium and welded titanium in LiBr solutions. Corrosion Science, 49(3), 1000-1026. doi:10.1016/j.corsci.2006.07.007Huang, Y. Z., & Blackwood, D. J. (2005). Characterisation of titanium oxide film grown in 0.9% NaCl at different sweep rates. Electrochimica Acta, 51(6), 1099-1107. doi:10.1016/j.electacta.2005.05.051Pan, J., Thierry, D., & Leygraf, C. (1996). Electrochemical impedance spectroscopy study of the passive oxide film on titanium for implant application. Electrochimica Acta, 41(7-8), 1143-1153. doi:10.1016/0013-4686(95)00465-3Assis, S. L. de, Wolynec, S., & Costa, I. (2006). Corrosion characterization of titanium alloys by electrochemical techniques. Electrochimica Acta, 51(8-9), 1815-1819. doi:10.1016/j.electacta.2005.02.121Birch, J. R., & Burleigh, T. D. (2000). Oxides Formed on Titanium by Polishing, Etching, Anodizing, or Thermal Oxidizing. CORROSION, 56(12), 1233-1241. doi:10.5006/1.3280511Peláez-Abellán, E., Rocha-Sousa, L., Müller, W.-D., & Guastaldi, A. C. (2007). Electrochemical stability of anodic titanium oxide films grown at potentials higher than 3V in a simulated physiological solution. Corrosion Science, 49(3), 1645-1655. doi:10.1016/j.corsci.2006.08.010Azumi, K., & Seo, M. (2001). Changes in electrochemical properties of the anodic oxide film formed on titanium during potential sweep. Corrosion Science, 43(3), 533-546. doi:10.1016/s0010-938x(00)00105-0Alves, V. A., Reis, R. Q., Santos, I. C. B., Souza, D. G., de F. Gonçalves, T., Pereira-da-Silva, M. A., … da Silva, L. A. (2009). In situ impedance spectroscopy study of the electrochemical corrosion of Ti and Ti–6Al–4V in simulated body fluid at 25°C and 37°C. Corrosion Science, 51(10), 2473-2482. doi:10.1016/j.corsci.2009.06.035Schmidt, A. M., Azambuja, D. S., & Martini, E. M. A. (2006). Semiconductive properties of titanium anodic oxide films in McIlvaine buffer solution. Corrosion Science, 48(10), 2901-2912. doi:10.1016/j.corsci.2005.10.013Sellers, M. C. K., & Seebauer, E. G. (2011). Measurement method for carrier concentration in TiO2 via the Mott–Schottky approach. Thin Solid Films, 519(7), 2103-2110. doi:10.1016/j.tsf.2010.10.071Jiang, Z., Dai, X., & Middleton, H. (2011). Investigation on passivity of titanium under steady-state conditions in acidic solutions. Materials Chemistry and Physics, 126(3), 859-865. doi:10.1016/j.matchemphys.2010.12.028Kong, D.-S., Lu, W.-H., Feng, Y.-Y., Yu, Z.-Y., Wu, J.-X., Fan, W.-J., & Liu, H.-Y. (2009). Studying on the Point-Defect-Conductive Property of the Semiconducting Anodic Oxide Films on Titanium. Journal of The Electrochemical Society, 156(1), C39. doi:10.1149/1.3021008Roh, B., & Macdonald, D. D. (2007). Effect of oxygen vacancies in anodic titanium oxide films on the kinetics of the oxygen electrode reaction. Russian Journal of Electrochemistry, 43(2), 125-135. doi:10.1134/s1023193507020012Sazou, D., Saltidou, K., & Pagitsas, M. (2012). Understanding the effect of bromides on the stability of titanium oxide films based on a point defect model. Electrochimica Acta, 76, 48-61. doi:10.1016/j.electacta.2012.04.158Roberge P. R. , Handbook of Corrosion Engineering, p. 756, McGraw-Hill, New York (2000).Basame, S. B., & White, H. S. (1995). Scanning electrochemical microscopy of native titanium oxide films. Mapping the potential dependence of spatially-localized electrochemical reactions. The Journal of Physical Chemistry, 99(44), 16430-16435. doi:10.1021/j100044a034Basame, S. B., & White, H. S. (2000). Pitting Corrosion of Titanium The Relationship Between Pitting Potential and Competitive Anion Adsorption at the Oxide Film/Electrolyte Interface. Journal of The Electrochemical Society, 147(4), 1376. doi:10.1149/1.1393364Dugdale, I., & Cotton, J. B. (1964). The anodic polarization of titanium in halide solutions. Corrosion Science, 4(1-4), 397-411. doi:10.1016/0010-938x(64)90041-1Virtanen, S., & Curty, C. (2004). Metastable and Stable Pitting Corrosion of Titanium in Halide Solutions. CORROSION, 60(7), 643-649. doi:10.5006/1.3287839Trompette, J. L., Massot, L., Arurault, L., & Fontorbes, S. (2011). Influence of the anion specificity on the anodic polarization of titanium. Corrosion Science, 53(4), 1262-1268. doi:10.1016/j.corsci.2010.12.021Casillas, N. (1994). 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D. (2011). The history of the Point Defect Model for the passive state: A brief review of film growth aspects. Electrochimica Acta, 56(4), 1761-1772. doi:10.1016/j.electacta.2010.11.005Macdonald, D. D., & Sun, A. (2006). An electrochemical impedance spectroscopic study of the passive state on Alloy-22. Electrochimica Acta, 51(8-9), 1767-1779. doi:10.1016/j.electacta.2005.02.103Park, K., Ahn, S., & Kwon, H. (2011). Effects of solution temperature on the kinetic nature of passive film on Ni. Electrochimica Acta, 56(3), 1662-1669. doi:10.1016/j.electacta.2010.09.077Macdonald, D. D. (2008). On the tenuous nature of passivity and its role in the isolation of HLNW. Journal of Nuclear Materials, 379(1-3), 24-32. doi:10.1016/j.jnucmat.2008.06.004Paola, A. D. (1989). Semiconducting properties of passive films on stainless steels. Electrochimica Acta, 34(2), 203-210. doi:10.1016/0013-4686(89)87086-0Gomes, W. P., & Vanmaekelbergh, D. (1996). Impedance spectroscopy at semiconductor electrodes: Review and recent developments. Electrochimica Acta, 41(7-8), 967-973. doi:10.1016/0013-4686(95)00427-0Da Cunha Belo, M., Hakiki, N. ., & Ferreira, M. G. . (1999). Semiconducting properties of passive films formed on nickel–base alloys type Alloy 600: influence of the alloying elements. Electrochimica Acta, 44(14), 2473-2481. doi:10.1016/s0013-4686(98)00372-7Hakiki, N. B., Boudin, S., Rondot, B., & Da Cunha Belo, M. (1995). The electronic structure of passive films formed on stainless steels. Corrosion Science, 37(11), 1809-1822. doi:10.1016/0010-938x(95)00084-wHamadou, L., Kadri, A., & Benbrahim, N. (2005). Characterisation of passive films formed on low carbon steel in borate buffer solution (pH 9.2) by electrochemical impedance spectroscopy. Applied Surface Science, 252(5), 1510-1519. doi:10.1016/j.apsusc.2005.02.135Wijesinghe, T. L. S. L., & Blackwood, D. J. (2008). Photocurrent and capacitance investigations into the nature of the passive films on austenitic stainless steels. Corrosion Science, 50(1), 23-34. doi:10.1016/j.corsci.2007.06.009Amri, J., Souier, T., Malki, B., & Baroux, B. (2008). Effect of the final annealing of cold rolled stainless steels sheets on the electronic properties and pit nucleation resistance of passive films. Corrosion Science, 50(2), 431-435. doi:10.1016/j.corsci.2007.08.013Li, D. G., Wang, J. D., & Chen, D. R. (2012). Influence of potentiostatic aging, temperature and pH on the diffusivity of a point defect in the passive film on Nb in an HCl solution. Electrochimica Acta, 60, 134-146. doi:10.1016/j.electacta.2011.11.024Fernández-Domene, R. M., Blasco-Tamarit, E., García-García, D. M., & García-Antón, J. (2013). Passive and transpassive behaviour of Alloy 31 in a heavy brine LiBr solution. Electrochimica Acta, 95, 1-11. doi:10.1016/j.electacta.2013.02.024Urquidi-Macdonald, M. (1989). Theoretical Analysis of the Effects of Alloying Elements on Distribution Functions of Passivity Breakdown. Journal of The Electrochemical Society, 136(4), 961. doi:10.1149/1.2096894Schmidt, A. M., & Azambuja, D. S. (2006). Electrochemical behavior of Ti and Ti6Al4V in aqueous solutions of citric acid containing halides. Materials Research, 9(4), 387-392. doi:10.1590/s1516-14392006000400008Brug, G. J., van den Eeden, A. L. G., Sluyters-Rehbach, M., & Sluyters, J. H. (1984). The analysis of electrode impedances complicated by the presence of a constant phase element. Journal of Electroanalytical Chemistry and Interfacial Electrochemistry, 176(1-2), 275-295. doi:10.1016/s0022-0728(84)80324-1Valero Vidal, C., & Igual Muñoz, A. (2010). Study of the adsorption process of bovine serum albumin on passivated surfaces of CoCrMo biomedical alloy. Electrochimica Acta, 55(28), 8445-8452. doi:10.1016/j.electacta.2010.07.028Smart, N. G., & Bockris, J. O. (1992). Effect of Water Activity on Corrosion. CORROSION, 48(4), 277-280. doi:10.5006/1.3315933Frankel, G. S. (1998). Pitting Corrosion of Metals. Journal of The Electrochemical Society, 145(6), 2186. doi:10.1149/1.1838615Blasco-Tamarit, E., Igual-Muñoz, A., & García-Antón, J. (2007). Galvanic corrosion of high alloyed austenitic stainless steel welds in LiBr systems. Corrosion Science, 49(12), 4452-4471. doi:10.1016/j.corsci.2007.05.020Crozier, P. S., & Rowley, R. L. (2002). Activity coefficient prediction by osmotic molecular dynamics. Fluid Phase Equilibria, 193(1-2), 53-73. doi:10.1016/s0378-3812(01)00734-8Burstein, G. T. (1989). The Dissolution and Repassivation of New Titanium Surfaces in Alkaline Methanolic Solution. Journal of The Electrochemical Society, 136(5), 1313. doi:10.1149/1.2096913Banaś, J., Stypuła, B., Banaś, K., Światowska-Mrowiecka, J., Starowicz, M., & Lelek-Borkowska, U. (2008). Corrosion and passivity of metals in methanol solutions of electrolytes. 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Improving the solar zenith angle dependence of broadband UV radiometers calibration

International audienceThis paper focusses on the proposal of a new method for the calibration of broadband ultraviolet radiometers. The advantage of the method proposed is the accurate modelling of the dependence on the solar zenith angle. The new model is compared with other one-step calibration methods and with the two-step method, which requires the knowledge of the actual response of the broadband radiometer. For this purpose, three broadband radiometers are calibrated against a spectrophotometer of reference. The new method is validated comparing its predictions with the spectrophotometer measurements using an independent data set

Passive Behavior and Passivity Breakdown of AISI 304 in LiBr Solutions through Scanning Electrochemical Microscopy

The passive behavior and passivity breakdown of AISI 304 stainless steel in LiBr solutions has been investigated by means of scanning electrochemical microscopy (SECM). The sample generation - tip collection (SG-TC) mode was used to operate the SECM and the tip potential was biased to detect the electroactive species. The evolution of the current at the ultramicroelectrode tip with the applied potential within the passive range was followed at different LiBr concentrations. Results show that the absolute value of the current at the tip increases with the applied potential. Additionally, SECM was also used to detect stable pits formed on the stainless steel surface in a 0.2 M LiBr solution. The results show clear evidence of the presence of high amounts of other reducible species (metal cations) apart from oxygen. Also, the dish-shape morphology of the pits observed using Confocal Laser Scanning Microscopy will be discussed in relation to the kinetics of the reactions observed using SECM. (c) 2014 The Electrochemical Society. All rights reserved.The authors would like to express their gratitude to the Generalitat Valenciana for its help in the SECM acquisition (PPC/2011/013) and in the CLSM acquisition (MY08/ISIRM/S/100) and to Dr. Asuncion Jaime for her translation assistance.Fernández Domene, RM.; Sánchez Tovar, R.; García Antón, J. (2014). Passive Behavior and Passivity Breakdown of AISI 304 in LiBr Solutions through Scanning Electrochemical Microscopy. Journal of The Electrochemical Society. 161(12):565-572. https://doi.org/10.1149/2.1051412jesS56557216112Cobb Harold M. (Ed.), Steel Products Manual: Stainless Steels, Iron & Steel Society, 1999.Schweitzer P. A. , Corrosion Engineering Handbook: Fundamentals of Metallic Corrosion, CRC Press, Boca Ratón, FL., 2007.Hakiki, N. B., Boudin, S., Rondot, B., & Da Cunha Belo, M. (1995). The electronic structure of passive films formed on stainless steels. Corrosion Science, 37(11), 1809-1822. doi:10.1016/0010-938x(95)00084-wWijesinghe, T. L. S. L., & Blackwood, D. J. (2008). Photocurrent and capacitance investigations into the nature of the passive films on austenitic stainless steels. Corrosion Science, 50(1), 23-34. doi:10.1016/j.corsci.2007.06.009Hakiki, N. E. (1998). Semiconducting Properties of Passive Films Formed on Stainless Steels. Journal of The Electrochemical Society, 145(11), 3821. doi:10.1149/1.1838880Olefjord, I. (1985). Surface Composition of Stainless Steels during Anodic Dissolution and Passivation Studied by ESCA. Journal of The Electrochemical Society, 132(12), 2854. doi:10.1149/1.2113683Lothongkum, G., Chaikittisilp, S., & Lothongkum, A. . (2003). XPS investigation of surface films on high Cr-Ni ferritic and austenitic stainless steels. Applied Surface Science, 218(1-4), 203-210. doi:10.1016/s0169-4332(03)00600-7Freire, L., Carmezim, M. J., Ferreira, M. G. S., & Montemor, M. F. (2010). The passive behaviour of AISI 316 in alkaline media and the effect of pH: A combined electrochemical and analytical study. Electrochimica Acta, 55(21), 6174-6181. doi:10.1016/j.electacta.2009.10.026Roberge P. R. , Corrosion Engineering. Principles and Practice, 1st. ed., McGraw-Hill, New York, NY, 2008.Wipf, D. O. (1994). Initiation and study of localized corrosion by scanning electrochemical microscopy. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 93, 251-261. doi:10.1016/0927-7757(94)02872-9Casillas, N. (1994). Pitting Corrosion of Titanium. Journal of The Electrochemical Society, 141(3), 636. doi:10.1149/1.2054783Basame, S. B., & White, H. S. (1995). Scanning electrochemical microscopy of native titanium oxide films. Mapping the potential dependence of spatially-localized electrochemical reactions. The Journal of Physical Chemistry, 99(44), 16430-16435. doi:10.1021/j100044a034Still, J. W. (1997). Breakdown of the Iron Passive Layer by Use of the Scanning Electrochemical Microscope. Journal of The Electrochemical Society, 144(8), 2657. doi:10.1149/1.1837879Zhu, Y. (1997). Scanning Electrochemical Microscopic Observation of a Precursor State to Pitting Corrosion of Stainless Steel. Journal of The Electrochemical Society, 144(3), L43. doi:10.1149/1.1837487Basame, S. B., & White, H. S. (1998). Scanning Electrochemical Microscopy:  Measurement of the Current Density at Microscopic Redox-Active Sites on Titanium. The Journal of Physical Chemistry B, 102(49), 9812-9819. doi:10.1021/jp982088xWilliams, D. E. (1998). Elucidation of a Trigger Mechanism for Pitting Corrosion of Stainless Steels Using Submicron Resolution Scanning Electrochemical and Photoelectrochemical Microscopy. Journal of The Electrochemical Society, 145(8), 2664. doi:10.1149/1.1838697Lister, T. E., & Pinhero, P. J. (2002). Scanning Electrochemical Microscopy Study of Corrosion Dynamics on Type 304 Stainless Steel. Electrochemical and Solid-State Letters, 5(11), B33. doi:10.1149/1.1510621Lister, T. E., & Pinhero, P. J. (2003). The effect of localized electric fields on the detection of dissolved sulfur species from Type 304 stainless steel using scanning electrochemical microscopy. Electrochimica Acta, 48(17), 2371-2378. doi:10.1016/s0013-4686(03)00228-7González-Garcı́a, Y., Burstein, G. ., González, S., & Souto, R. . (2004). Imaging metastable pits on austenitic stainless steel in situ at the open-circuit corrosion potential. Electrochemistry Communications, 6(7), 637-642. doi:10.1016/j.elecom.2004.04.018Souto, R. M., González-Garcı́a, Y., & González, S. (2005). In situ monitoring of electroactive species by using the scanning electrochemical microscope. Application to the investigation of degradation processes at defective coated metals. 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Visualization of local degradation processes in coated metals by means of scanning electrochemical microscopy in the redox competition mode. Electrochimica Acta, 55(15), 4488-4494. doi:10.1016/j.electacta.2010.02.091González-García, Y., Santana, J. J., González-Guzmán, J., Izquierdo, J., González, S., & Souto, R. M. (2010). Scanning electrochemical microscopy for the investigation of localized degradation processes in coated metals. Progress in Organic Coatings, 69(2), 110-117. doi:10.1016/j.porgcoat.2010.04.006Yuan, Y., Li, L., Wang, C., & Zhu, Y. (2010). Study of the effects of hydrogen on the pitting processes of X70 carbon steel with SECM. Electrochemistry Communications, 12(12), 1804-1807. doi:10.1016/j.elecom.2010.10.031Aouina, N., Balbaud-Célérier, F., Huet, F., Joiret, S., Perrot, H., Rouillard, F., & Vivier, V. (2011). Single pit initiation on 316L austenitic stainless steel using scanning electrochemical microscopy. 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Electrochemical behaviour of thermally treated Cr-oxide films deposited on stainless steel. Corrosion Science, 44(3), 451-465. doi:10.1016/s0010-938x(01)00076-2Sharma S. K. , Green Corrosion Chemistry and Engineering: Opportunities and Challenges, Wiley-VCH Verlag GmbH & Co., First Edition, Germany, 2012.Venkatraman, M. S., Cole, I. S., & Emmanuel, B. (2011). Corrosion under a porous layer: A porous electrode model and its implications for self-repair. Electrochimica Acta, 56(24), 8192-8203. doi:10.1016/j.electacta.2011.06.020Thomas, S., Cole, I. S., Sridhar, M., & Birbilis, N. (2013). Revisiting zinc passivation in alkaline solutions. Electrochimica Acta, 97, 192-201. doi:10.1016/j.electacta.2013.03.008Gao, S., Dong, C., Luo, H., Xiao, K., Pan, X., & Li, X. (2013). Scanning electrochemical microscopy study on the electrochemical behavior of CrN film formed on 304 stainless steel by magnetron sputtering. 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Analysis of a low ozone episode over Extremadura (Spain) in January 2006 and its influence on UV radiation

The main objectives of this work are to analyze, firstly, the detail of the causes of a low ozone event which occurred in January 2006 and, secondly, the related effects of this anomalous episode on ultraviolet (UV) radiation measured at three locations in Extremadura (South-Western Spain). On 19 January 2006, the OMI total ozone column (TOC) was 16–20% below the January mean value of TOMS/NASA TOC (period 1996–2005). The back trajectories analysis with the HYSplit model indicates that the notable decrease of TOC could be attributed to a fast rise of the isentropic trajectories height. Concomitantly, UV erythemal radiation greatly increases (between 23% and 37%) on 19 January 2006 respect to UV erythemal radiation measured on 19 January 2005. This notable increase in winter UV solar radiation may involve harmful effects for organisms adapted to receive less radiation during that season (e.g. early developmental stages of terrestrial plants and phytoplankton)

Variabilidad de los conjuntos líticos en el Paleolítico Medio del Abric Romaní (Capellades, Barcelona)

El Abric Romaní cuenta con una potente secuencia del Paleolítico Medio de la que hasta el momento se han excavado 13 niveles arqueológicos. Estos niveles muestran un patrón de ocupación basado en la aparición de espacios domésticos en torno a hogares en los que se concentra la mayor parte de las actividades, especialmente las relacionadas con el procesamiento de los recursos líticos. Este patrón permite caracterizar el Abric Romaní como un espacio residencial, lo que es fundamental para entender el registro arqueológico y el comportamiento técnico. La variabilidad de los conjuntos líticos se ha abordado desde una triple perspectiva, relacionada con las diferentes escalas temporales a las que es posible acceder a través de la metodología arqueológica: la variabilidad que refleja procesos de larga duración y que se expresa en los cambios que se producen a lo largo de la secuencia; la variabilidad en el interior de conjunto lítico definido a partir de criterios estratigráficos; y la variabilidad accesible a través de contextos temporales de alta resolución. Esta última aproximación a la variabilidad se centra en el estudio de los diferentes comportamientos discernibles en un mismo nivel arqueológico. En este trabajo utilizaremos el nivel J como ejemplo de este tipo de análisis.L'Abric Romaní compta amb una potent seqüència del Paleolític Mitjà de qual, fins al moment, s'han excavat 13 nivells arqueològics. Aquests nivells mostren un patró d'ocupació basat en l'aparició d'espais domèstics entorn a fogars en els quals es concentren la major part de les activitats, especialment les relacionades amb el processament dels recursos lítics. Aquest patró permet caracteritzar l'Abric Romaní com un espai residencial, fet que és fonamental per entendre el registre arqueològic i el comportament tècnic. La variabilitat dels conjunts lítics s'ha tractat des d'una triple perspectiva, relacionada amb les diferents escales temporals a les quals és possible accedir a través de la metodologia arqueològica: la variabilitat que reflecteix processos de llarga duració i que s'expressa en els canvis que es produeixen al llarg de la seqüència; la variabilitat en l'interior del conjunt lític definit a partir de criteris estratigràfics; i la variabilitat accessible a través de contextos temporals d'alta resolució. Aquesta última aproximació a la variabilitat se centra en l'estudi dels diferents comportaments discernibles en un mateix nivell arqueològic. En aquest treball utilitzarem el nivell J com a exemple d'aquest tipus d'anàlisi.L'Abric Romaní compte avec une puissante séquence du Paléolithique Moyen dont, actuellement, ont uniquement été fouillés 13 niveaux archéologiques. Ces niveaux montrent un patron d'occupation basé sur l'apparition d'espaces domestiques autour des foyers dans lesquels se concentrent la plupart des activités, spécialement celles qui sont en relation avec la taille des ressources lithiques. Ce patron permet de caractériser l'Abri Romaní comme espace résidentiel, ce qui est fondamental pour comprendre le registre archéologique et le comportement technique. La variabilité des ensembles lithiques a été traitée suivant une triple perspective, mise en relation avec les différentes échelles temporelles auxquelles il est possible d'y accéder par la méthodologie archéologique: la variabilité qui montre des processus de longue durée et qui se donne par les changements produits tout le long de la séquence ; la variabilité à l'intérieur de l'ensemble lithique défini suivant des critères stratigraphiques ; et la variabilité accessible à partir des contextes temporels d'haute résolution. Cette dernière approche à la variabilité se centre sur l'étude des différents comportements discernables dans un même niveau archéologique. Dans ce travail, on utilisera le niveau J comme exemple de ce type d'analyse.Abric Romani contains a thick Middle Palaeolithic sequence of which 13 archaeological levels have been excavated so far. Occupation patterns in these levels are organized in domestic spaces around hearths in which most of activities are concentrated, especially those concerning the management of lithic material. This pattern portrays Abric Romani as a residential space, and that is essential to understanding its archaeological record and technical behaviour. Variability of the lithic assemblages has been assessed according to three different temporal scales feasible of being investigated with archaeological methods; variability in long term scales, as shown by changes throughout the sequence; variability in lithic assemblages within a single stratigraphic level; and variability in high resolution temporal contexts. The latter is approached through the study of different behaviours detected within the same archaeological level. In this paper, level J will be used as a case study to tackle this type of analysis

Genetic study of the colour coat in the characterisation of the equine breeds

The genetic determination of the coat horses is controlled by the interaction of the alleles of 5 loci ( C, B, A, E and D). They will determine the basic colour and other loci modify them. The knowledge of their effects and interactions could help us to fix the coat permitted in the standard racial, helping us to eliminate the genes coming from other breeds, permitting, at the same time, to accept or eliminate other coats determinate by recessive alleles. The study of the inheritance of the coat colour in the autochthonous Spanish breeds has allowed concluding that those have a great number of fixed alleles for the coat colour. The W allele is loosing in all the autochthonous Spanish breeds and the D allele do not appear. The shady phenotypes do not exit in Spain. In the P.R.E. has got a paradox: animals with chestnut coat are not admitted, but isabella coat are considered like P.R.E., being this last a dilution of the chestnut coat (determined for the Ccr allele).La determinación genética del color de la capa en los caballos viene dada por la interacción de los alelos de 5 loci ( C, B, A, E y D), responsables de las capas básicas, y otros loci que pueden modificarlas. Sus efectos e interacciones pueden ayudarnos a fijar las capas permitidas en el estándar racial, ayudándonos a eliminar los genes procedentes de patrones raciales ajenos con el objetivo de la recuperación racial, permitiendo, al mismo tiempo, aceptar o eliminar otras capas dependientes de genes homocigotos recesivos no visibles en el fenotipo pero presentes en el genotipo. El estudio de la herencia del color de la capa de las razas autóctonas españolas nos ha permitido concluir que las razas españolas cuya cría tradicional ha sido muy circunscrita geográficamente poseen un gran número de genes fijados para el color de la capa. El alelo W se ha perdido en todas las razas autóctonas españolas y el alelo D no aparece. No existen los fenotipos umbríos en ninguna raza explotada en España. En el P.R.E. existe una paradoja, al no admitirse animales con capa alazana y sí con la capa isabela, siendo esta última una dilución de la capa alazana (dada por el alelo Ccr)

Two-Stage Nonparametric Regression for Longitudinal Data

In the analysis of longitudinal data it is of main interest to investigate the existence of group and individual effects under correlated observations across time. In this paper, we develop a nonparametric two-step procedure that enables us to estimate group effects under a very general form of correlation across time. Moreover, we propose several methods to estimate the bandwidth and show their asymptotyc optimality. Since the asymptotic distribution is untractable, we develop a randomization test that is suitable for testing the group effects. Finally, we apply the estimation procedure, the bandwidth selection criteria and the randomization test to the data from the Iowa Cochlear Implant Project.This work was supported by Dirección General de Enseñanza Superior del Ministerio Español de Educación y Cultura and Universidad del País Vasco (UPV/EHU) under research grant PB95-0346

El sistema caprino extensivo en la sierra norte y este de Jaén, como base del desarrollo sostenible

En los quince municipios de menos de 5000 habitantes, localizados en el Parque Natural de Cazorla, Segura y Las Villas se ha puesto de manifiesto un proceso de despoblación, envejecimiento y empobrecimiento. La desaparición del mundo rural es un indicador de la degradación medioambiental. El presente trabajo pretende valorar técnica y económicamente el sector caprino de este parque natural, así como su nivel de competencia con el bosque mediterráneo. El estudio se centra en una muestra representativa de las explotaciones de caprino autóctono extensivo del parque natural, constituida por 63 rebaños, que representan el 60 p.100 del total de explotaciones La dimensión media de las explotaciones es de 213 cabras, con una UTH dedicada al caprino y dos por granja. El sistema productivo es eminentemente pastoril, de carácter familiar, con razas autóctonas muy adaptadas, pastos comunales y un régimen característico de pacería, denominado costeo y con unos canales de comercialización ineficientes. El ganado caprino (sin contabilizar el ovino y el vacuno) permite facturar por término medio 1.800.000 pta y generar un flujo de caja en torno a las 300.000 pta al año. Los valores de carga (0,78 UO por ha) están en consonancia con la capacidad sustentadora del parque entre 0,31 y 0,92 UO por ha (Gallego et al., 1991) y son inferiores a lo manifestados por Fernández Rebollo (1995). Además de la importancia económica y social del sistema productivo de carácter sustentable, se ha de tener presente que los protagonistas del desarrollo sostenible son los habitantes del medio rural y estos han de participar la adopción de decisiones

Fabrication of Ordered and High-Performance Nanostructured Photoelectrocatalysts by Electrochemical Anodization: Influence of Hydrodynamic Conditions

Nanostructured semiconductor metal oxides, such as TiO2, WO3, Fe2O3 or ZnO, are being widely investigated for their use as photoanodes, due to their higher surface areas in contact with the electrolyte, which increases the efficiency of photoelectrochemical processes. Metal oxide nanostructures have been synthesized by a number of different techniques. Anodization is one of the simpler methods used to synthesize nanostructured photoanodes, and the morphology and size of nanostructures can be designed by adequately controlling anodization parameters. Besides, these nanostructures are directly bound to the metallic back contact, improving significantly the efficiency of electron collection. It has been observed that hydrodynamic conditions during anodization (using a rotating disk electrode, RDE) greatly influenced the morphology of nanostructures and, therefore, their photoelectrochemical performance. The objective of this chapter is to review the innovative nanostructures with high-aspect ratios that can be fabricated by anodization under different hydrodynamic conditions