Estudio de los picos tallados de la época preeuropea de Gran Canaria. Un ejemplo de especialización en el trabajo a partir de las evidencias recuperadas en la cantera de molinos de Montaña Quemada

In this paper we present the study of chipped stone picks. These instruments were employed to work rocks in several ways(working in quarries, excavating mine galleries and other enclosures, manufacturing tools, etc.). The artifacts were recoveredin the excavation of a quarry for the production of rotator milling stones (Montaña Quemada, Gran Canaria). In thequarries intensive productive processes were developed, where picks were submitted to strong mechanical and frictionalstresses, which caused frequent accidents requiring continuous repairs. These circumstances made it necessary to developa type of artifact with technical features that allowed reshaping and resharpening tasks in order to extend its active life. Acombination of morphotechnical and functional studies, along with the refitting results, have enabled us to reconstruct theirknapping and use strategies, showing a high level of skill. In addition, this analysis has involved defining, for the first time,the different categories of byproducts generated during the process of the configuration and reconfiguration of the picks.Their detailed description will make it possible to recognize them in other archaeological contexts.En este artículo se presentan los resultados del estudio de una muestra de picos de piedra tallada, útiles empleadospara trabajar la piedra en diversas labores (cantería, excavación de cuevas y minas, fabricación de herramientas…),procedentes de la excavación de una cantera de molinos de mano rotatorios (Montaña Quemada, Gran Canaria). Enlas canteras se desarrollaron unos procesos productivos intensivos, en los que los picos eran sometidos a un fuerteestrés mecánico y de fricción, que provocaba numerosos accidentes y desgastes, exigiendo continuas reparaciones. Elloobligó a concebir un tipo de artefacto con unas características que permitieran realizar gestos de remodelación queperduraran su vida activa. La combinación de los estudios morfotécnicos, funcionales y los remontajes obtenidos hapermitido reconstruir unas estrategias de talla y de uso que revelan un gran conocimiento del arte de la talla y la cantería.En este análisis se han definido por primera vez las diversas categorías de productos generados en esos procesos,lo que permitirá reconocerlas en los diversos contextos arqueológicos de la isla

Exploring the intricate evolutionary history of the diploid-polyploid complexVeronica subsection Pentasepalae(Plantaginaceae)

[EN]Veronica subsection Pentasepalae is a diploid–polyploid complex of c. 20 species distributed in Eurasia and North Africa, in which species boundaries are difficult to determine. Here, we present the first comprehensive phylogenetic analysis of V. subsection Pentasepalae based on nucleotide sequences [internal transcribed spacer (ITS) and the plastid trnH-psbA and ycf6-psbM spacers] combined with ploidy estimations. Our results support the monophyly of the subsection. Five well-supported clades are recovered in the ITS sequence analyses, corresponding to broad geographical areas. The causes of the extensive incongruence found between the ITS and plastid DNA datasets, namely incomplete lineage sorting and/or hybridization and polyploidization, are discussed. Most of the diploids traditionally recognized based on morphological characters and one tetraploid are each recovered as monophyletic by the ITS sequence analyses. The Balkan species V. kindlii is resurrected. DNA ploidy level for V. teucrioides is reported here for the first time (2x). Diploid populations have been found for V. orbiculata, which was previously thought to be only tetraploid. Past contact in the amphi-Adriatic area between V. orsiniana and V. orbiculata is suggested. Finally, molecular analyses show that diploid V. jacquinii and diploid V. orbiculata are unrelated. This study contributes to our understanding of the evolutionary history of polyploid complexes, especially those in southern Europe, and highlights the importance of using multiple lines of evidence to investigate species boundaries in such actively diversifying groups

Synthesis and characterization of titanium-vanadium ternary nitride (TixV1-xN).

En el presente trabajo se aborda la síntesis del nitruro ternario de titanio y vanadio por reducción carbotérmica de una mezcla de óxidos o bien por nitruración directa de la mezcla de metales, en todo el rango de composiciones empleando el método de análisis térmico a velocidad controlada (ATVC). La caracterización de los productos obtenidos se ha llevado a cabo mediante difracción de rayos-X y microscopia electrónica. El empleo de la técnica EELS ha mostrado su capacidad para la cuantificación de este tipo de materiales, así como la utilización de la técnica espectroscópica XAS nos ha servido para corroborar los datos obtenidos a partir de los diagramas de difracción de rayos-X sobre distancias de enlace, número de coordinación y grado de desorden, esto último no detectado por las otras técnicas usadas en la caracterización de los productos. Los valores de microdureza registrados para las muestras sintetizadas se encuentran dentro del rango de valores reportados para este tipo de materiales.Titanium-Vanadium nitride (TiVN) has been prepared from carbothermal reduction of corresponding oxides and also by direct nitridation of a mix of two metals employing the ATVC method. The characterization of the final product by X-ray diffraction, scanning electron microscopy, electron energy loss (EELS), and X-ray absorption spectroscopy (XAS) is presented.The synthesis of the ternary nitride has been possible in all range of composition and the final product is obtained with nanometric particle size and a high microhardness after sintering

Lipoma intrauricular derecho. Reporte de un caso

We present the case of a 56-year-old male patient with a history of atrial flutter for six months; he was admitted to the hospital for presenting a mass of 8 cm in maximum diameter in the right atrium, which prolapsed through the tricuspid valve into the right ventricle. Emergency surgery was scheduled, performing exeresis of the tumor and tricuspid annuloplasty. The Pathological anatomy determined that the removed mass corresponded to a cardiac lipoma.Se presenta el caso de un paciente varón de 56 años, con antecedente de Flutter auricular desde hace 6 meses; ingresó al hospital por presentar una masa de 8 cm de diámetro máximo en la aurícula derecha, la cual prolapsaba a través de la válvula tricúspide hacia el ventrículo derecho. Se programó la cirugía de urgencia en la que se realizó la exéresis de la tumoración y la anuloplastia tricuspídea. La anatomía patológica determinó que la masa extraida correspondía a un lipoma cardiaco

Barley seed coating with free and immobilized alkaline phosphatase to improve P uptake and plant growth

Coating barley seeds with free and immobilized alkaline phosphatase was investigated as a potential means to enhance plant utilization of accumulated soil phosphorus (P). Two coating techniques were studied: film-coating and pelleting. The highest phosphatase activity retention in the coating layer, ranging from 0·48 to 0·67, was observed when seeds were film-coated with phosphatase–polyresorcinol complex (PPC). The germination of seeds film-coated or pelleted with alkaline phosphatase ranged from 0·84 to 0·97 or 0·14 to 0·25, respectively. Low germination of the pelleted seeds was attributed to freezing the seeds in liquid nitrogen (N) for the layer coating formation. Pelleted seeds were not used in the remainder of the studies. Under pot culture conditions, an increase in the soil inorganic P was detected when the seeds were film-coated with phosphatase. Moreover, the film-coating significantly increased the P uptake by plants (between 25 and 31% after 35 days after planting (DAP)). The present study showed that the seed film-coating with free and immobilized phosphatase increased the phosphatase activity in the rhizosphere and the P uptake by plants

Chronopotentiometric study of the transport of phosphoric acid anions through an anion-exchange membrane under different pH values

[EN] Phosphate is the main cause of eutrophication in many water bodies. Its presence in waters is associated to the fact that is not completely removed in conventional wastewater treatment plants. On the other side, phosphate rocks are a non-renewable resource and considered as a critical raw material. A membrane separation process, able to recover phosphate from wastewater, is a promising process to avoid pollution and to reuse phosphate. This paper investigates the transport of salts of phosphoric acid through an anion-exchange membrane (AEM) by means of chronopotentiograms and polarization curves (CVCs). The presence of multiple transition times in the chronopotentiograms and the corresponding limiting current densities in the CVCs indicate a change in the species being transported in the membrane/diffusion boundary layer system, due to the hydrolysis reactions that take place when the concentration polarization is reached. Under the experimental conditions tested, coupled convection (gravitational and elctroconvection) occurs when a certain threshold in the membrane voltage drop is surpassed independently of the electrolyte concentration. However, at high pH values, only one transition time in the chronopotentiograms, due to the transfer of OH- ions with greater concentration and mobility. This fact is reflected in the CVCs by the large plateaus obtained, which hinders the occurrence of coupled convection phenomena, and consequently, water splitting can be considered as the main mechanism responsible for the overlimiting regime.The authors wish to thank the financial support from FINEP, FAPERGS, CAPES and CNPq (Brazil), from the BRICS-STI/CNPq (BRICS STI Framework Programme), from the European Union through the Erasmus Mundus Program (EBW +) and from the CYTED (Network 318RT0551).Gally, C.; García Gabaldón, M.; Ortega Navarro, EM.; Bernardes, A.; Pérez-Herranz, V. (2020). Chronopotentiometric study of the transport of phosphoric acid anions through an anion-exchange membrane under different pH values. Separation and Purification Technology. 238:1-10. https://doi.org/10.1016/j.seppur.2019.116421S110238Cordell, D., Drangert, J.-O., & White, S. (2009). The story of phosphorus: Global food security and food for thought. Global Environmental Change, 19(2), 292-305. doi:10.1016/j.gloenvcha.2008.10.009Cordell, D., Rosemarin, A., Schröder, J. J., & Smit, A. L. (2011). Towards global phosphorus security: A systems framework for phosphorus recovery and reuse options. Chemosphere, 84(6), 747-758. doi:10.1016/j.chemosphere.2011.02.032Van Vuuren, D. P., Bouwman, A. F., & Beusen, A. H. W. (2010). Phosphorus demand for the 1970–2100 period: A scenario analysis of resource depletion. Global Environmental Change, 20(3), 428-439. doi:10.1016/j.gloenvcha.2010.04.004Gilbert, N. (2009). Environment: The disappearing nutrient. Nature, 461(7265), 716-718. doi:10.1038/461716aHao, X., Wang, C., van Loosdrecht, M. C. M., & Hu, Y. (2013). Looking Beyond Struvite for P-Recovery. Environmental Science & Technology, 47(10), 4965-4966. doi:10.1021/es401140sArnaldos, M., & Pagilla, K. (2010). Effluent dissolved organic nitrogen and dissolved phosphorus removal by enhanced coagulation and microfiltration. Water Research, 44(18), 5306-5315. doi:10.1016/j.watres.2010.06.066Babatunde, A. O., & Zhao, Y. Q. (2010). Equilibrium and kinetic analysis of phosphorus adsorption from aqueous solution using waste alum sludge. Journal of Hazardous Materials, 184(1-3), 746-752. doi:10.1016/j.jhazmat.2010.08.102Kralchevska, R. P., Prucek, R., Kolařík, J., Tuček, J., Machala, L., Filip, J., … Zbořil, R. (2016). Remarkable efficiency of phosphate removal: Ferrate(VI)-induced in situ sorption on core-shell nanoparticles. Water Research, 103, 83-91. doi:10.1016/j.watres.2016.07.021Maher, C., Neethling, J. B., Murthy, S., & Pagilla, K. (2015). Kinetics and capacities of phosphorus sorption to tertiary stage wastewater alum solids, and process implications for achieving low-level phosphorus effluents. Water Research, 85, 226-234. doi:10.1016/j.watres.2015.08.025Furuya, K., Hafuka, A., Kuroiwa, M., Satoh, H., Watanabe, Y., & Yamamura, H. (2017). Development of novel polysulfone membranes with embedded zirconium sulfate-surfactant micelle mesostructure for phosphate recovery from water through membrane filtration. Water Research, 124, 521-526. doi:10.1016/j.watres.2017.08.005Zhang, Y., Desmidt, E., Van Looveren, A., Pinoy, L., Meesschaert, B., & Van der Bruggen, B. (2013). Phosphate Separation and Recovery from Wastewater by Novel Electrodialysis. Environmental Science & Technology, 47(11), 5888-5895. doi:10.1021/es4004476Valverde-Pérez, B., Wágner, D. S., Lóránt, B., Gülay, A., Smets, B. F., & Plósz, B. G. (2016). Short-sludge age EBPR process – Microbial and biochemical process characterisation during reactor start-up and operation. Water Research, 104, 320-329. doi:10.1016/j.watres.2016.08.026Chen, X., Zhou, H., Zuo, K., Zhou, Y., Wang, Q., Sun, D., … Huang, X. (2017). Self-sustaining advanced wastewater purification and simultaneous in situ nutrient recovery in a novel bioelectrochemical system. Chemical Engineering Journal, 330, 692-697. doi:10.1016/j.cej.2017.07.130Le Corre, K. S., Valsami-Jones, E., Hobbs, P., & Parsons, S. A. (2009). Phosphorus Recovery from Wastewater by Struvite Crystallization: A Review. Critical Reviews in Environmental Science and Technology, 39(6), 433-477. doi:10.1080/10643380701640573Ueno, Y., & Fujii, M. (2001). Three Years Experience of Operating and Selling Recovered Struvite from Full-Scale Plant. Environmental Technology, 22(11), 1373-1381. doi:10.1080/09593332208618196Battistoni, P., Boccadoro, R., Fatone, F., & Pavan, P. (2005). Auto-Nucleation and Crystal Growth of Struvite in a Demonstrative Fluidized Bed Reactor (FBR). Environmental Technology, 26(9), 975-982. doi:10.1080/09593332608618486Liu, R., Wang, Y., Wu, G., Luo, J., & Wang, S. (2017). Development of a selective electrodialysis for nutrient recovery and desalination during secondary effluent treatment. Chemical Engineering Journal, 322, 224-233. doi:10.1016/j.cej.2017.03.149Ren, S., Li, M., Sun, J., Bian, Y., Zuo, K., Zhang, X., … Huang, X. (2017). A novel electrochemical reactor for nitrogen and phosphorus recovery from domestic wastewater. Frontiers of Environmental Science & Engineering, 11(4). doi:10.1007/s11783-017-0983-xWimalasiri, Y., Mossad, M., & Zou, L. (2015). Thermodynamics and kinetics of adsorption of ammonium ions by graphene laminate electrodes in capacitive deionization. Desalination, 357, 178-188. doi:10.1016/j.desal.2014.11.015Huang, G.-H., Chen, T.-C., Hsu, S.-F., Huang, Y.-H., & Chuang, S.-H. (2013). Capacitive deionization (CDI) for removal of phosphate from aqueous solution. Desalination and Water Treatment, 52(4-6), 759-765. doi:10.1080/19443994.2013.826331Wang, X., Wang, Y., Zhang, X., Feng, H., Li, C., & Xu, T. (2013). Phosphate Recovery from Excess Sludge by Conventional Electrodialysis (CED) and Electrodialysis with Bipolar Membranes (EDBM). Industrial & Engineering Chemistry Research, 52(45), 15896-15904. doi:10.1021/ie4014088Ebbers, B., Ottosen, L. M., & Jensen, P. E. (2015). Electrodialytic treatment of municipal wastewater and sludge for the removal of heavy metals and recovery of phosphorus. Electrochimica Acta, 181, 90-99. doi:10.1016/j.electacta.2015.04.097Pismenskaya, N., Nikonenko, V., Auclair, B., & Pourcelly, G. (2001). Transport of weak-electrolyte anions through anion exchange membranes. Journal of Membrane Science, 189(1), 129-140. doi:10.1016/s0376-7388(01)00405-7Belashova, E. D., Kharchenko, O. A., Sarapulova, V. V., Nikonenko, V. V., & Pismenskaya, N. D. (2017). Effect of Protolysis Reactions on the Shape of Chronopotentiograms of a Homogeneous Anion-Exchange Membrane in NaH2PO4 Solution. Petroleum Chemistry, 57(13), 1207-1218. doi:10.1134/s0965544117130035Belashova, E. D., Pismenskaya, N. D., Nikonenko, V. V., Sistat, P., & Pourcelly, G. (2017). Current-voltage characteristic of anion-exchange membrane in monosodium phosphate solution. Modelling and experiment. Journal of Membrane Science, 542, 177-185. doi:10.1016/j.memsci.2017.08.002Melnikova, E. D., Pismenskaya, N. D., Bazinet, L., Mikhaylin, S., & Nikonenko, V. V. (2018). Effect of ampholyte nature on current-voltage characteristic of anion-exchange membrane. Electrochimica Acta, 285, 185-191. doi:10.1016/j.electacta.2018.07.186Paltrinieri, L., Poltorak, L., Chu, L., Puts, T., van Baak, W., Sudhölter, E. J. R., & de Smet, L. C. P. M. (2018). Hybrid polyelectrolyte-anion exchange membrane and its interaction with phosphate. Reactive and Functional Polymers, 133, 126-135. doi:10.1016/j.reactfunctpolym.2018.10.005Rybalkina, O., Tsygurina, K., Melnikova, E., Mareev, S., Moroz, I., Nikonenko, V., & Pismenskaya, N. (2019). Partial Fluxes of Phosphoric Acid Anions through Anion-Exchange Membranes in the Course of NaH2PO4 Solution Electrodialysis. International Journal of Molecular Sciences, 20(14), 3593. doi:10.3390/ijms20143593Martí-Calatayud, M. C., Buzzi, D. C., García-Gabaldón, M., Bernardes, A. M., Tenório, J. A. S., & Pérez-Herranz, V. (2014). Ion transport through homogeneous and heterogeneous ion-exchange membranes in single salt and multicomponent electrolyte solutions. Journal of Membrane Science, 466, 45-57. doi:10.1016/j.memsci.2014.04.033Benvenuti, T., García-Gabaldón, M., Ortega, E. M., Rodrigues, M. A. S., Bernardes, A. M., Pérez-Herranz, V., & Zoppas-Ferreira, J. (2017). Influence of the co-ions on the transport of sulfate through anion exchange membranes. Journal of Membrane Science, 542, 320-328. doi:10.1016/j.memsci.2017.08.021Ray, P., Shahi, V. K., Pathak, T. V., & Ramachandraiah, G. (1999). Transport phenomenon as a function of counter and co-ions in solution: chronopotentiometric behavior of anion exchange membrane in different aqueous electrolyte solutions. Journal of Membrane Science, 160(2), 243-254. doi:10.1016/s0376-7388(99)00088-5Martí-Calatayud, M. C., García-Gabaldón, M., Pérez-Herranz, V., & Ortega, E. (2011). Determination of transport properties of Ni(II) through a Nafion cation-exchange membrane in chromic acid solutions. Journal of Membrane Science, 379(1-2), 449-458. doi:10.1016/j.memsci.2011.06.014Marder, L., Ortega Navarro, E. M., Pérez-Herranz, V., Bernardes, A. M., & Ferreira, J. Z. (2006). Evaluation of transition metals transport properties through a cation-exchange membrane by chronopotentiometry. Journal of Membrane Science, 284(1-2), 267-275. doi:10.1016/j.memsci.2006.07.039Herraiz-Cardona, I., Ortega, E., & Pérez-Herranz, V. (2010). Evaluation of the Zn2+ transport properties through a cation-exchange membrane by chronopotentiometry. Journal of Colloid and Interface Science, 341(2), 380-385. doi:10.1016/j.jcis.2009.09.053Martí-Calatayud, M. C., García-Gabaldón, M., & Pérez-Herranz, V. (2012). Study of the effects of the applied current regime and the concentration of chromic acid on the transport of Ni2+ ions through Nafion 117 membranes. Journal of Membrane Science, 392-393, 137-149. doi:10.1016/j.memsci.2011.12.012Pismenskaia, N., Sistat, P., Huguet, P., Nikonenko, V., & Pourcelly, G. (2004). Chronopotentiometry applied to the study of ion transfer through anion exchange membranes. Journal of Membrane Science, 228(1), 65-76. doi:10.1016/j.memsci.2003.09.012Taky, M., Pourcelly, G., Lebon, F., & Gavach, C. (1992). Polarization phenomena at the interfaces between an electrolyte solution and an ion exchange membrane. Journal of Electroanalytical Chemistry, 336(1-2), 171-194. doi:10.1016/0022-0728(92)80270-eNikonenko, V. V., Pismenskaya, N. D., Belova, E. I., Sistat, P., Huguet, P., Pourcelly, G., & Larchet, C. (2010). Intensive current transfer in membrane systems: Modelling, mechanisms and application in electrodialysis. Advances in Colloid and Interface Science, 160(1-2), 101-123. doi:10.1016/j.cis.2010.08.001Krol, J. (1999). Concentration polarization with monopolar ion exchange membranes: currentâ voltage curves and water dissociation. Journal of Membrane Science, 162(1-2), 145-154. doi:10.1016/s0376-7388(99)00133-7Larchet, C., Nouri, S., Auclair, B., Dammak, L., & Nikonenko, V. (2008). Application of chronopotentiometry to determine the thickness of diffusion layer adjacent to an ion-exchange membrane under natural convection. Advances in Colloid and Interface Science, 139(1-2), 45-61. doi:10.1016/j.cis.2008.01.007Scarazzato, T., Panossian, Z., García-Gabaldón, M., Ortega, E. M., Tenório, J. A. S., Pérez-Herranz, V., & Espinosa, D. C. R. (2017). Evaluation of the transport properties of copper ions through a heterogeneous ion-exchange membrane in etidronic acid solutions by chronopotentiometry. Journal of Membrane Science, 535, 268-278. doi:10.1016/j.memsci.2017.04.048Zook, J. M., Bodor, S., Gyurcsányi, R. E., & Lindner, E. (2010). Interpretation of chronopotentiometric transients of ion-selective membranes with two transition times. Journal of Electroanalytical Chemistry, 638(2), 254-261. doi:10.1016/j.jelechem.2009.11.007Martí-Calatayud, M. C., García-Gabaldón, M., & Pérez-Herranz, V. (2013). Effect of the equilibria of multivalent metal sulfates on the transport through cation-exchange membranes at different current regimes. Journal of Membrane Science, 443, 181-192. doi:10.1016/j.memsci.2013.04.058Maletzki, F., Rösler, H.-W., & Staude, E. (1992). Ion transfer across electrodialysis membranes in the overlimiting current range: stationary voltage current characteristics and current noise power spectra under different conditions of free convection. Journal of Membrane Science, 71(1-2), 105-116. doi:10.1016/0376-7388(92)85010-gElena I. Belova, Galina Yu. Lopatkova, Natalia D. Pismenskaya, Victor V. Nikonenko, and Christian Larchet, G. Pourcelly, Effect of Anion-exchange Membrane Surface Properties on Mechanisms of Overlimiting Mass Transfer, (2006). doi:10.1021/JP062433F.Nikonenko, V. V., Kovalenko, A. V., Urtenov, M. K., Pismenskaya, N. D., Han, J., Sistat, P., & Pourcelly, G. (2014). Desalination at overlimiting currents: State-of-the-art and perspectives. Desalination, 342, 85-106. doi:10.1016/j.desal.2014.01.008Liu, X., Vlugt, T. J. H., & Bardow, A. (2011). Predictive Darken Equation for Maxwell-Stefan Diffusivities in Multicomponent Mixtures. Industrial & Engineering Chemistry Research, 50(17), 10350-10358. doi:10.1021/ie201008aElattar, A., Elmidaoui, A., Pismenskaia, N., Gavach, C., & Pourcelly, G. (1998). Comparison of transport properties of monovalent anions through anion-exchange membranes. Journal of Membrane Science, 143(1-2), 249-261. doi:10.1016/s0376-7388(98)00013-1Choi, J.-H., Lee, H.-J., & Moon, S.-H. (2001). Effects of Electrolytes on the Transport Phenomena in a Cation-Exchange Membrane. Journal of Colloid and Interface Science, 238(1), 188-195. doi:10.1006/jcis.2001.7510Agmon, N. (1995). The Grotthuss mechanism. Chemical Physics Letters, 244(5-6), 456-462. doi:10.1016/0009-2614(95)00905-jChen, C., Tse, Y.-L. S., Lindberg, G. E., Knight, C., & Voth, G. A. (2016). Hydroxide Solvation and Transport in Anion Exchange Membranes. Journal of the American Chemical Society, 138(3), 991-1000. doi:10.1021/jacs.5b11951Wang, C., Mo, B., He, Z., Xie, X., Zhao, C. X., Zhang, L., … Guo, Z. (2018). Hydroxide ions transportation in polynorbornene anion exchange membrane. Polymer, 138, 363-368. doi:10.1016/j.polymer.2018.01.079Pismenskaya, N. D., Nikonenko, V. V., Belova, E. I., Lopatkova, G. Y., Sistat, P., Pourcelly, G., & Larshe, K. (2007). Coupled convection of solution near the surface of ion-exchange membranes in intensive current regimes. Russian Journal of Electrochemistry, 43(3), 307-327. doi:10.1134/s102319350703010xPis’menskaya, N. D., Nikonenko, V. V., Mel’nik, N. A., Pourcelli, G., & Larchet, G. (2012). Effect of the ion-exchange-membrane/solution interfacial characteristics on the mass transfer at severe current regimes. Russian Journal of Electrochemistry, 48(6), 610-628. doi:10.1134/s1023193512060092Belova, E., Lopatkova, G., Pismenskaya, N., Nikonenko, V., & Larchet, C. (2006). Role of water splitting in development of electroconvection in ion-exchange membrane systems. Desalination, 199(1-3), 59-61. doi:10.1016/j.desal.2006.03.14

Peculiar properties of chlorophyll thermoluminescence emission of autotrophically or mixotrophically grown Chlamydomonas reinhardtii

The microalgae Chlamydomonas reinhardtii and Chlorella sp. CCAP 211/84 were grown autotrophically and mixotrophically and their thermoluminescence emissions were recorded above 0 °C after excitation by 1, 2 or 3 xenon flashes or by continuous far-red light. An oscillation of the B band intensity according to the number of flashes was always observed, with a maximum after 2 flashes, accompanied by a downshift of the B band temperature maximum in mixotrophic compared to autotrophic grown cells, indicative of a dark stable pH gradient. Moreover, new flash-induced bands emerged in mixotrophic Chlamydomonas grown cells, at temperatures higher than that of the B band. In contrast to the afterglow band observed in higher plants, in Chlamydomonas these bands were not inducible by far-red light, were fully suppressed by 2 μM antimycin A, and peaked at different temperatures depending on the flash number and growth stage, with higher temperature maxima in cells at a stationary compared to an exponential growth stage. These differences are discussed according to the particular properties of cyclic electron transfer pathways in C. reinhardtii.Ministerio de Educación y Cultura BFU2007-68107-C02-01/BMCJunta de Andalucía PAIDI CVI-26

Presencia de malnutrición y riesgo de malnutrición en ancianos institucionalizados con demencia en función del tipo y estadío evolutivo

Producción CientíficaDeterminar si existen diferencias en el estado nutricional de los pacientes con demencia en función del tipo y la severidad de la misma. Método: Mediante un estudio transversal se realizó una valoración del estado nutricional (valoración antropométrica, Mini Nutricional Assessment, protocolo de Chang) en 83 ancianos institucionalizados con diagnóstico de demencia en estadíos evolutivos 5, 6 y 7 de las escalas GDS (Global Deterioration Scale) y FAST (Functional Assessment Stating). Los resultados se analizaron mediante los tests Chi-cuadrado, ANOVA o Kruskal-Wallis, contrastes a posteriori de Scheffé y test de tendencia lineal. La significación se alcanzó con p < 0,05. Resultados: La edad media de los residentes fue de 81,22 años. El IMC reveló que el 21% de la muestra presentaba riesgo de malnutrición y el 14,5% malnutrición por defecto. En cambio, el MNA clasificó al 56,6% de los residentes en situación de riesgo de malnutrición y al 41% con malnutrición. Según el método de Chang el porcentaje de pacientes malnutridos ascendió al 75,9%. Ninguna de estas variables mostró asociación con el tipo de demencia. Se observó una asociación significativa entre el estadío evolutivo de la demencia y el IMC (p = 0,004), MNA (p = 0,002 y p = 0,006 para la puntuación y la categoría, respectivamente), circunferencia muscular del brazo (p = 0,043) y circunferencia de la pantorrilla (p = 0,043); aunque no para el porcentaje de masa grasa ni para el diagnóstico nutricional establecido por el método de Chang (grado y tipo de MN). El test de tendencia lineal confirmó que tanto las puntuaciones del MNA y del IMC, como los valores de la circunferencia muscular del brazo y de la circunferencia de la pantorrilla fueron menores en los estadíos de demencia más severos. Conclusión: Independientemente del tipo de demencia, la presencia de malnutrición en ancianos institucionalizados aumenta conforme lo hace el estadío evolutivo de la misma

El coeficiente de correlación de los rangos de Spearman, caracterización

En el ámbito de las investigaciones clínico-epidemiológicas, los profesionales de la salud asiduamente se proyectan en  sus investigaciones; se definen  las relaciones entre las  características de un fenómeno, el grado de esa relación o probar la confiabilidad de sus observaciones, planteándose como hipótesis si estas son o no la causa de una determinada entidad. En la práctica, generalmente, acontece que el investigador entre las disímiles pruebas estadísticas de las que dispone, no selecciona adecuadamente la que con mayor cientificidad le aportará una lectura fácil de dicha relaciones. Se realiza una revisión bibliográfica con el objetivo  de caracterizar el método de correlación de rangos de Spearman, utilizado para valorar la asociación entre variables cuantitativas, aplicándose el método de análisis documental .Los resultados son declarados al resumir la historia del surgimiento de  la teoría de la correlación y  la regresión, explicación de conceptos asociados, su presentación gráfica, los  rasgos esenciales del algoritmo de solución tradicional y con asesor estadístico, así como una compilación sobre escalas de interpretación de la prueba estadística. Se  proyecta que el trabajo realizado sirva de bibliografía a consultar por investigadores y estudiantes de las Ciencias Médicas.   Palabras clave: Correlación, Spearman, Pearson, Correlación de Spearman, estadística, regresión, correlación lineal,  coeficiente de correlación, rangos, psicología diferencial, histori