Exact Phase Diagram of a model with Aggregation and Chipping

We revisit a simple lattice model of aggregation in which masses diffuse and coalesce upon contact with rate 1 and every nonzero mass chips off a single unit of mass to a randomly chosen neighbour with rate $w$. The dynamics conserves the average mass density $\rho$ and in the stationary state the system undergoes a nonequilibrium phase transition in the $(\rho-w)$ plane across a critical line $\rho_c(w)$. In this paper, we show analytically that in arbitrary spatial dimensions, $\rho_c(w) = \sqrt{w+1}-1$ exactly and hence, remarkably, independent of dimension. We also provide direct and indirect numerical evidence that strongly suggest that the mean field asymptotic answer for the single site mass distribution function and the associated critical exponents are super-universal, i.e., independent of dimension.Comment: 11 pages, RevTex, 3 figure

Palynology of the Permian San Miguel Formation (Western Paraná Basin, Paraguay): Gondwanan biostratigraphic correlations

The palynological analysis of five samples from three levels in cores of the Mallorquín-1 well (Paraná Basin, eastern Paraguay) is presented here. The borehole penetrated the San Miguel Formation, the basal lithostratigraphic unit of the Independencia Group. This palynoflora represents the westernmost palynological record reported from Upper Paleozoic sequences along this basin margin at this latitude. This diverse spore pollen flora includes several age marker taxa, viz. Verrucosisporites insuetus, Lueckisporites spp., Lunatisporites variesectus, Striatosporites heyleri, Weylandites lucifer, and Tornopollenites toreutos, as well as Reduviasporonites chalastus. The assemblages from the Mallorquín-1 well are assignable to the Lueckisporites virkkiae Zone from the Brazilian sector of the Paraná Basin, thus suggesting a Late Cisuralian-Guadalupian age for the section studied and its correlation with the Brazilian Palermo and Irati Formations. Moreover, palynostratigraphic regional correlation can be established with the Tornopollenites toreutos Biozone (northern Brazil), the Striatites and Lueckisporites Weylandites Biozones (Argentina) and the Striatoabieites anaverrucosus-Staurosaccites cordubensis Biozone (Uruguay). The presence of abundant taeniate pollen also suggests similarities with palynofloras from South Africa and Australia

Influence of dietary supplementation with sunflower oil and quebracho tannins on growth performance and meat fatty acid profile of Awassi lambs

The inclusion of QT in the diet increased the content of the conjugated linoleic acid in the lamb meat above that achieved with SF supplementation only. Addition of the combination of QT and SF to the diet enhanced the content of conjugated linoleic acid (C18:2 c9t11) of the lamb meat. This could be due to the reduction in the bio-hydrogenation of unsaturated fatty acids in the diet. The results suggest that inclusion the combination of QT and SF in lamb diets improved the healthy fatty acids content in the meat without an adverse effect on animal performance.The influence of dietary supplementation with quebracho tannins (QT) or/and sunflower oil (SF) on growth performance and fatty acid profile in meat of Awassi lambs was studied. Seventy-two lambs were assigned randomly to nine diets (8 per group) in the experiment following a 32 factorial design with all possible combinations of two factors, SF and QT each at three levels i.e. 0 (control), 20 or 40 g/kg diet DM. A significant SF ×QT interaction was observed on the conjugated linoleic acid content of intramuscular fat (P =0.007), but not on average daily weight gain (P=0.11). Addition of QT at 40 g/ kg DM significantly increased average daily gain comparing to control diet

Transport Properties of Random Walks on Scale-Free/Regular-Lattice Hybrid Networks

We study numerically the mean access times for random walks on hybrid disordered structures formed by embedding scale-free networks into regular lattices, considering different transition rates for steps across lattice bonds ($F$) and across network shortcuts ($f$). For fast shortcuts ($f/F\gg 1$) and low shortcut densities, traversal time data collapse onto an universal curve, while a crossover behavior that can be related to the percolation threshold of the scale-free network component is identified at higher shortcut densities, in analogy to similar observations reported recently in Newman-Watts small-world networks. Furthermore, we observe that random walk traversal times are larger for networks with a higher degree of inhomogeneity in their shortcut distribution, and we discuss access time distributions as functions of the initial and final node degrees. These findings are relevant, in particular, when considering the optimization of existing information networks by the addition of a small number of fast shortcut connections.Comment: 8 pages, 6 figures; expanded discussions, added figures and references. To appear in J Stat Phy

High-pressure study of ScVO4 by Raman scattering and ab initio calculations

We report results of experimental and theoretical lattice-dynamics studies on scandium orthovanadate up to 35 GPa. Raman-active modes of the low-pressure zircon phase are measured up to 8.2 GPa, where the onset of an irreversible zircon-to-scheelite phase transition is detected. Raman-active modes in the scheelite structure are observed up to 16.5 GPa. Beyond 18.2 GPa we detected a gradual splitting of the Eg modes of the scheelite phase, indicating the onset of a second phase transition. Raman symmetries, frequencies, and pressure coefficients in the three phases of ScVO4 are discussed in the light of ab initio lattice-dynamics calculations that support the experimental results. The results on all the three phases of ScVO4 are compared with those previously reported for related orthovanadates.We acknowledge the financial support of the Spanish MCYT under Grants No. MAT2007-65990-C03-01/03, No. MAT2010-21270-C04-01/03/04, and No. CSD2007-00045, and the computation time provided by the Red Espanola de Supercomputacion and the supercomputer Atlante. F.J.M. acknowledges also financial support from "Vicerrectorado de Innovacion y Desarrollo de la UPV" (No. PAID-05-2009 through Project No. UPV2010-0096). Some of the authors are members of the MALTA Consolider Team.Panchal, V.; Manjón Herrera, FJ.; Errandonea, D.; Rodriguez-Hernandez, P.; López-Solano, J.; Muñoz, A.; Achary, S.... (2011). High-pressure study of ScVO4 by Raman scattering and ab initio calculations. Physical Review B. 83(6):641111-1-64111-10. https://doi.org/10.1103/PhysRevB.83.064111S641111-164111-10836Shafi, S. P., Kotyk, M. W., Cranswick, L. M. D., Michaelis, V. K., Kroeker, S., & Bieringer, M. (2009). In Situ Powder X-ray Diffraction, Synthesis, and Magnetic Properties of the Defect Zircon Structure ScVO4−x. Inorganic Chemistry, 48(22), 10553-10559. doi:10.1021/ic900927jMullica, D. F., Sappenfield, E. L., Abraham, M. M., Chakoumakos, B. C., & Boatner, L. A. (1996). Structural investigations of several LnVO4 compounds. Inorganica Chimica Acta, 248(1), 85-88. doi:10.1016/0020-1693(95)04971-1Errandonea, D., & Manjón, F. J. (2008). Pressure effects on the structural and electronic properties of ABX4 scintillating crystals. Progress in Materials Science, 53(4), 711-773. doi:10.1016/j.pmatsci.2008.02.001Aldred, A. T. (1984). Cell volumes of APO4, AVO4, and ANbO4 compounds, where A = Sc, Y, La–Lu. Acta Crystallographica Section B Structural Science, 40(6), 569-574. doi:10.1107/s0108768184002718Errandonea, D., Lacomba-Perales, R., Ruiz-Fuertes, J., Segura, A., Achary, S. N., & Tyagi, A. K. (2009). High-pressure structural investigation of several zircon-type orthovanadates. Physical Review B, 79(18). doi:10.1103/physrevb.79.184104López-Solano, J., Rodríguez-Hernández, P., & Muñoz, A. (2009). Ab initiostudy of high-pressure structural properties of the LuVO4and ScVO4zircon-type orthovanadates. High Pressure Research, 29(4), 582-586. doi:10.1080/08957950903417444Manjón, F. J., Rodríguez-Hernández, P., Muñoz, A., Romero, A. H., Errandonea, D., & Syassen, K. (2010). Lattice dynamics ofYVO4at high pressures. Physical Review B, 81(7). doi:10.1103/physrevb.81.075202Wang, X., Loa, I., Syassen, K., Hanfland, M., & Ferrand, B. (2004). Structural properties of the zircon- and scheelite-type phases ofYVO4at high pressure. Physical Review B, 70(6). doi:10.1103/physrevb.70.064109Klotz, S., Chervin, J.-C., Munsch, P., & Le Marchand, G. (2009). Hydrostatic limits of 11 pressure transmitting media. Journal of Physics D: Applied Physics, 42(7), 075413. doi:10.1088/0022-3727/42/7/075413Errandonea, D., Meng, Y., Somayazulu, M., & Häusermann, D. (2005). Pressure-induced transition in titanium metal: a systematic study of the effects of uniaxial stress. Physica B: Condensed Matter, 355(1-4), 116-125. doi:10.1016/j.physb.2004.10.030Mao, H. K., Xu, J., & Bell, P. M. (1986). Calibration of the ruby pressure gauge to 800 kbar under quasi-hydrostatic conditions. Journal of Geophysical Research, 91(B5), 4673. doi:10.1029/jb091ib05p04673Kresse, G., & Furthmüller, J. (1996). Efficient iterative schemes forab initiototal-energy calculations using a plane-wave basis set. Physical Review B, 54(16), 11169-11186. doi:10.1103/physrevb.54.11169Kresse, G., & Joubert, D. (1999). From ultrasoft pseudopotentials to the projector augmented-wave method. Physical Review B, 59(3), 1758-1775. doi:10.1103/physrevb.59.1758Blöchl, P. E. (1994). Projector augmented-wave method. Physical Review B, 50(24), 17953-17979. doi:10.1103/physrevb.50.17953Perdew, J. P., Burke, K., & Ernzerhof, M. (1996). Generalized Gradient Approximation Made Simple. Physical Review Letters, 77(18), 3865-3868. doi:10.1103/physrevlett.77.3865Mujica, A., Rubio, A., Muñoz, A., & Needs, R. J. (2003). High-pressure phases of group-IV, III–V, and II–VI compounds. Reviews of Modern Physics, 75(3), 863-912. doi:10.1103/revmodphys.75.863Guedes, I., Hirano, Y., Grimsditch, M., Wakabayashi, N., Loong, C.-K., & Boatner, L. A. (2001). Raman study of phonon modes in ErVO4 single crystals. Journal of Applied Physics, 90(4), 1843-1846. doi:10.1063/1.1384858Garg, A. B., Rao, R., Sakuntala, T., Wani, B. N., & Vijayakumar, V. (2009). Phase stability of YbVO4 under pressure: In situ x-ray and Raman spectroscopic investigations. Journal of Applied Physics, 106(6), 063513. doi:10.1063/1.3223327Santos, C. C., Silva, E. N., Ayala, A. P., Guedes, I., Pizani, P. S., Loong, C.-K., & Boatner, L. A. (2007). Raman investigations of rare earth orthovanadates. Journal of Applied Physics, 101(5), 053511. doi:10.1063/1.2437676Zhang, F. X., Wang, J. W., Lang, M., Zhang, J. M., Ewing, R. C., & Boatner, L. A. (2009). High-pressure phase transitions ofScPO4andYPO4. Physical Review B, 80(18). doi:10.1103/physrevb.80.184114Tossell, J. A. (1975). Electronic structures of silicon, aluminum, and magnesium in tetrahedral coordination with oxygen from SCF-X.alpha. MO calculations. Journal of the American Chemical Society, 97(17), 4840-4844. doi:10.1021/ja00850a010Rao, R., Garg, A. B., Sakuntala, T., Achary, S. N., & Tyagi, A. K. (2009). High pressure Raman scattering study on the phase stability of LuVO4. Journal of Solid State Chemistry, 182(7), 1879-1883. doi:10.1016/j.jssc.2009.05.003Duclos, S. J., Jayaraman, A., Espinosa, G. P., Cooper, A. S., & Maines, R. G. (1989). Raman and optical absorption studies of the pressure-induced zircon to scheelite structure transformation in TbVO4 and DyV04. Journal of Physics and Chemistry of Solids, 50(8), 769-775. doi:10.1016/0022-3697(89)90055-3Smirnov, M. B., Mirgorodsky, A. P., Kazimirov, V. Y., & Guinebretière, R. (2008). Bond-switching mechanism for the zircon-scheelite phase transition. Physical Review B, 78(9). doi:10.1103/physrevb.78.094109Flórez, M., Contreras-García, J., Recio, J. M., & Marqués, M. (2009). Quantum-mechanical calculations of zircon to scheelite transition pathways inZrSiO4. Physical Review B, 79(10). doi:10.1103/physrevb.79.104101Rousseau, D. L., Bauman, R. P., & Porto, S. P. S. (1981). Normal mode determination in crystals. Journal of Raman Spectroscopy, 10(1), 253-290. doi:10.1002/jrs.1250100152Mittal, R., Garg, A. B., Vijayakumar, V., Achary, S. N., Tyagi, A. K., Godwal, B. K., … Chaplot, S. L. (2008). Investigation of the phase stability of LuVO4at high pressure using powder x-ray diffraction measurements and lattice dynamical calculations. Journal of Physics: Condensed Matter, 20(7), 075223. doi:10.1088/0953-8984/20/7/075223Manjón, F. J., Errandonea, D., Garro, N., Pellicer-Porres, J., Rodríguez-Hernández, P., Radescu, S., … Muñoz, A. (2006). Lattice dynamics study of scheelite tungstates under high pressure I.BaWO4. Physical Review B, 74(14). doi:10.1103/physrevb.74.144111Manjon, F. J., Errandonea, D., Garro, N., Pellicer-Porres, J., López-Solano, J., Rodríguez-Hernández, P., … Muñoz, A. (2006). Lattice dynamics study of scheelite tungstates under high pressure II.PbWO4. Physical Review B, 74(14). doi:10.1103/physrevb.74.144112Panchal, V., Garg, N., & Sharma, S. M. (2006). Raman and x-ray diffraction investigations on BaMoO4under high pressures. Journal of Physics: Condensed Matter, 18(16), 3917-3929. doi:10.1088/0953-8984/18/16/002Hardcastle, F. D., & Wachs, I. E. (1991). Determination of vanadium-oxygen bond distances and bond orders by Raman spectroscopy. The Journal of Physical Chemistry, 95(13), 5031-5041. doi:10.1021/j100166a025Brown, I. D., & Wu, K. K. (1976). Empirical parameters for calculating cation–oxygen bond valences. Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry, 32(7), 1957-1959. doi:10.1107/s0567740876006869Lacomba-Perales, R., Martinez-García, D., Errandonea, D., Le Godec, Y., Philippe, J., Le Marchand, G., … López-Solano, J. (2010). Experimental and theoretical investigation of the stability of the monoclinicBaWO4-II phase at high pressure and high temperature. Physical Review B, 81(14). doi:10.1103/physrevb.81.144117Tschauner, O., Errandonea, D., & Serghiou, G. (2006). Possible superlattice formation in high-temperature treated carbonaceous MgB2 at elevated pressure. Physica B: Condensed Matter, 371(1), 88-94. doi:10.1016/j.physb.2005.09.042Errandonea, D., Kumar, R. S., Ma, X., & Tu, C. (2008). High-pressure X-ray diffraction study of SrMoO4 and pressure-induced structural changes. Journal of Solid State Chemistry, 181(2), 355-364. doi:10.1016/j.jssc.2007.12.010Errandonea, D., Santamaria-Perez, D., Grover, V., Achary, S. N., & Tyagi, A. K. (2010). High-pressure x-ray diffraction study of bulk and nanocrystalline PbMoO4. Journal of Applied Physics, 108(7), 073518. doi:10.1063/1.3493048Errandonea, D., Santamaria-Perez, D., Bondarenko, T., & Khyzhun, O. (2010). New high-pressure phase of HfTiO4 and ZrTiO4 ceramics. Materials Research Bulletin, 45(11), 1732-1735. doi:10.1016/j.materresbull.2010.06.061Marqués, M., Flórez, M., Recio, J. M., Gerward, L., & Olsen, J. S. (2006). Structure and stability ofZrSiO4under hydrostatic pressure. Physical Review B, 74(1). doi:10.1103/physrevb.74.014104Lacomba-Perales, R., Errandonea, D., Meng, Y., & Bettinelli, M. (2010). High-pressure stability and compressibility ofAPO4(A=La, Nd, Eu, Gd, Er, and Y) orthophosphates: An x-ray diffraction study using synchrotron radiation. Physical Review B, 81(6). doi:10.1103/physrevb.81.064113Long, Y. W., Zhang, W. W., Yang, L. X., Yu, Y., Yu, R. C., Ding, S., … Jin, C. Q. (2005). Pressure-induced structural phase transition in CaCrO4: Evidence from Raman scattering studies. Applied Physics Letters, 87(18), 181901. doi:10.1063/1.2117624Long, Y. W., Yang, L. X., Yu, Y., Li, F. Y., Yu, R. C., Ding, S., … Jin, C. Q. (2006). High-pressure Raman scattering and structural phase transition inYCrO4. Physical Review B, 74(5). doi:10.1103/physrevb.74.054110Errandonea, D., Kumar, R. S., Gracia, L., Beltrán, A., Achary, S. N., & Tyagi, A. K. (2009). Experimental and theoretical investigation ofThGeO4at high pressure. Physical Review B, 80(9). doi:10.1103/physrevb.80.094101Gracia, L., Beltrán, A., & Errandonea, D. (2009). Characterization of theTiSiO4structure and its pressure-induced phase transformations: Density functional theory study. Physical Review B, 80(9). doi:10.1103/physrevb.80.094105Errandonea, D. (2007). Landau theory applied to phase transitions in calcium orthotungstate and isostructural compounds. Europhysics Letters (EPL), 77(5), 56001. doi:10.1209/0295-5075/77/56001Errandonea, D., & Manjón, F. J. (2009). On the ferroelastic nature of the scheelite-to-fergusonite phase transition in orthotungstates and orthomolybdates. Materials Research Bulletin, 44(4), 807-811. doi:10.1016/j.materresbull.2008.09.024Errandonea, D., Pellicer-Porres, J., Manjón, F. J., Segura, A., Ferrer-Roca, C., Kumar, R. S., … Aquilanti, G. (2005). High-pressure structural study of the scheelite tungstatesCaWO4andSrWO4. Physical Review B, 72(17). doi:10.1103/physrevb.72.174106Errandonea, D. (2005). High-pressure X-ray diffraction study of EuWO4 to 12 GPa. physica status solidi (b), 242(14), R125-R127. doi:10.1002/pssb.200541334Begun, G. M., Beall, G. W., Boatner, L. A., & Gregor, W. J. (1981). Raman spectra of the rare earth orthophosphates. Journal of Raman Spectroscopy, 11(4), 273-278. doi:10.1002/jrs.1250110411Podor, R. (1995). Raman spectra of the actinide-bearing monazites. European Journal of Mineralogy, 7(6), 1353-1360. doi:10.1127/ejm/7/6/1353Zhang, C. C., Zhang, Z. M., Dai, R. C., Wang, Z. P., Zhang, J. W., & Ding, Z. J. (2010). High-Pressure Raman and Luminescence Study on the Phase Transition of GdVO4:Eu3+ Microcrystals. The Journal of Physical Chemistry C, 114(42), 18279-18282. doi:10.1021/jp106063cVoron’ko, Y. K., Sobol’, A. A., Shukshin, V. E., Zagumennyĭ, A. I., Zavartsev, Y. D., & Kutovoĭ, S. A. (2009). Raman spectroscopic study of structural disordering in YVO4, GdVO4, and CaWO4 crystals. Physics of the Solid State, 51(9), 1886-1893. doi:10.1134/s1063783409090200Baran, E. J., Escobar, M. E., Fournier, L. L., & Filgueira, R. R. (1981). Die Raman-Spektren der Orthovanadate der Seltenen Erden. Zeitschrift f�r anorganische und allgemeine Chemie, 472(1), 193-199. doi:10.1002/zaac.19814720123Frost, R. L., Henry, D. A., Weier, M. L., & Martens, W. (2006). Raman spectroscopy of three polymorphs of BiVO4: clinobisvanite, dreyerite and pucherite, with comparisons to (VO4)3-bearing minerals: namibite, pottsite and schumacherite. Journal of Raman Spectroscopy, 37(7), 722-732. doi:10.1002/jrs.1499Blin, J. L., Lorriaux-Rubbens, A., Wallart, F., & Wignacourt, J. P. (1996). Synthesis and structural investigation of the Eu1–xBixVO4scheelite phase: X-ray diffraction, Raman scattering and Eu3+luminescence. J. Mater. Chem., 6(3), 385-389. doi:10.1039/jm9960600385Manjón, F. J., Errandonea, D., López-Solano, J., Rodríguez-Hernández, P., & Muñoz, A. (2009). Negative pressures in CaWO4 nanocrystals. Journal of Applied Physics, 105(9), 094321. doi:10.1063/1.3116727Tokunaga, S., Kato, H., & Kudo, A. (2001). Selective Preparation of Monoclinic and Tetragonal BiVO4with Scheelite Structure and Their Photocatalytic Properties. Chemistry of Materials, 13(12), 4624-4628. doi:10.1021/cm0103390Rice, C. E., & Robinson, W. R. (1976). Lanthanum orthovanadate. 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Bacteria Detection at a Single-Cell Level through a Cyanotype-Based Photochemical Reaction

Altres ajuts: Acord transformatiu CRUE-CSICAltres ajuts: Fundació Marató de TV3 (TV32018-201825-30-31)The detection of living organisms at very low concentrations is necessary for the early diagnosis of bacterial infections, but it is still challenging as there is a need for signal amplification. Cell culture, nucleic acid amplification, or nanostructure-based signal enhancement are the most common amplification methods, relying on long, tedious, complex, or expensive procedures. Here, we present a cyanotype-based photochemical amplification reaction enabling the detection of low bacterial concentrations up to a single-cell level. Photocatalysis is induced with visible light and requires bacterial metabolism of iron-based compounds to produce Prussian Blue. Bacterial activity is thus detected through the formation of an observable blue precipitate within 3 h of the reaction, which corresponds to the concentration of living organisms. The short time-to-result and simplicity of the reaction are expected to strongly impact the clinical diagnosis of infectious diseases

Influence of dietary supplementation with sunflower oil and quebracho tannins on growth performance and meat fatty acid profile of Awassi lambs

The influence of dietary supplementation with quebracho tannins (QT) or/and sunflower oil (SF) on growth performance and fatty acid profile in meat of Awassi lambs was studied. Seventy-two lambs were assigned randomly to nine diets (8 per group) in the experiment following a 32 factorial design with all possible combinations of two factors, SF and QT each at three levels i.e. 0 (control), 20 or 40 g/kg diet DM. A significant SF ×QT interaction was observed on the conjugated linoleic acid content of intramuscular fat (P =0.007), but not on average daily weight gain (P=0.11). Addition of QT at 40 g/ kg DM significantly increased average daily gain comparing to control diet. The inclusion of QT in the diet increased the content of the conjugated linoleic acid in the lamb meat above that achieved with SF supplementation only. Addition of the combination of QT and SF to the diet enhanced the content of conjugated linoleic acid (C18:2 c9t11) of the lamb meat. This could be due to the reduction in the bio-hydrogenation of unsaturated fatty acids in the diet. The results suggest that inclusion the combination of QT and SF in lamb diets improved the healthy fatty acids content in the meat without an adverse effect on animal performanc

Dynamic Ordering and Transverse Depinning of a Driven Elastic String in a Disordered Media

We examine the dynamics of an elastic string interacting with quenched disorder driven perpendicular and parallel to the string. We show that the string is the most disordered at the depinning transition but with increasing drive partial ordering is regained. For low drives the noise power is high and we observe a 1/f^2 noise signature crossing over to a white noise character with low power at higher drives. For the parallel driven moving string there is a finite transverse critical depinning force with the depinning transition occuring by the formation of running kinks.Comment: 4 pages, 4 postscript figure

A first-principles approach to electrical transport in atomic-scale nanostructures

We present a first-principles numerical implementation of Landauer formalism for electrical transport in nanostructures characterized down to the atomic level. The novelty and interest of our method lies essentially on two facts. First of all, it makes use of the versatile Gaussian98 code, which is widely used within the quantum chemistry community. Secondly, it incorporates the semi-infinite electrodes in a very generic and efficient way by means of Bethe lattices. We name this method the Gaussian Embedded Cluster Method (GECM). In order to make contact with other proposed implementations, we illustrate our technique by calculating the conductance in some well-studied systems such as metallic (Al and Au) nanocontacts and C-atom chains connected to metallic (Al and Au) electrodes. In the case of Al nanocontacts the conductance turns out to be quite dependent on the detailed atomic arrangement. On the contrary, the conductance in Au nanocontacts presents quite universal features. In the case of C chains, where the self-consistency guarantees the local charge transfer and the correct alignment of the molecular and electrode levels, we find that the conductance oscillates with the number of atoms in the chain regardless of the type of electrode. However, for short chains and Al electrodes the even-odd periodicity is reversed at equilibrium bond distances.Comment: 14 pages, two-column format, submitted to PR

The Listening Network and Cochlear Implant Benefits in Hearing-Impaired Adults

Older adults with mild or no hearing loss make more errors and expend more effort listening to speech. Cochlear implants (CI) restore hearing to deaf patients but with limited fidelity. We hypothesized that patient-reported hearing and health-related quality of life in CI patients may similarly vary according to age. Speech Spatial Qualities (SSQ) of hearing scale and Health Utilities Index Mark III (HUI) questionnaires were administered to 543 unilaterally implanted adults across Europe, South Africa, and South America. Data were acquired before surgery and at 1, 2, and 3 years post-surgery. Data were analyzed using linear mixed models with visit, age group (18–34, 35–44, 45–54, 55–64, and 65+), and side of implant as main factors and adjusted for other covariates. Tinnitus and dizziness prevalence did not vary with age, but older groups had more preoperative hearing. Preoperatively and postoperatively, SSQ scores were significantly higher (¿0.75–0.82) for those aged <45 compared with those 55+. However, gains in SSQ scores were equivalent across age groups, although postoperative SSQ scores were higher in right-ear implanted subjects. All age groups benefited equally in terms of HUI gain (0.18), with no decrease in scores with age. Overall, younger adults appeared to cope better with a degraded hearing before and after CI, leading to better subjective hearing performance.