Measuring Global Similarity between Texts

We propose a new similarity measure between texts which, contrary to the current state-of-the-art approaches, takes a global view of the texts to be compared. We have implemented a tool to compute our textual distance and conducted experiments on several corpuses of texts. The experiments show that our methods can reliably identify different global types of texts.Comment: Submitted to SLSP 201

Relevance of soft modes for order parameter fluctuations in the Two-Dimensional XY model

We analyse the spin wave approximation for the 2D-XY model, directly in reciprocal space. In this limit the model is diagonal and the normal modes are statistically independent. Despite this simplicity non-trivial critical properties are observed and exploited. We confirm that the observed asymmetry for the probability density function for order parameter fluctuations comes from the divergence of the mode amplitudes across the Brillouin zone. We show that the asymmetry is a many body effect despite the importance played by the zone centre. The precise form of the function is dependent on the details of the Gibbs measure, giving weight to the idea that an effective Gibbs measure should exist in non-equilibrium systems, if a similar distribution is observed.Comment: 12 pages, 9 figure

The male handicap: male-biased mortality explains skewed sex ratios in brown trout embryos

Juvenile sex ratios are often assumed to be equal for many species with genetic sex determination, but this has rarely been tested in fish embryos due to their small size and absence of sex-specific markers. We artificially crossed three populations of brown trout and used a recently developed genetic marker for sexing the offspring of both pure and hybrid crosses. Sex ratios (SR = proportion of males) varied widely one month after hatching ranging from 0.15 to 0.90 (mean = 0.39 ± 0.03). Families with high survival tended to produce balanced or male-biased sex ratios, but SR was significantly female-biased when survival was low, suggesting that males sustain higher mortality during development. No difference in SR was found between pure and hybrid families, but the existence of sire × dam interactions suggests that genetic incompatibility may play a role in determining sex ratios. Our findings have implications for animal breeding and conservation because skewed sex ratios will tend to reduce effective population size and bias selection estimates

UV Luminosity Functions from 132 z~7 and z~8 Lyman-Break Galaxies in the ultra-deep HUDF09 and wide-area ERS WFC3/IR Observations

We identify 73 z~7 and 59 z~8 candidate galaxies in the reionization epoch, and use this large 26-29.4 AB mag sample of galaxies to derive very deep luminosity functions to <-18 AB mag and the star formation rate density at z~7 and z~8. The galaxy sample is derived using a sophisticated Lyman-Break technique on the full two-year WFC3/IR and ACS data available over the HUDF09 (~29.4 AB mag, 5 sigma), two nearby HUDF09 fields (~29 AB mag, 14 arcmin) and the wider area ERS (~27.5 AB mag) ~40 arcmin**2). The application of strict optical non-detection criteria ensures the contamination fraction is kept low (just ~7% in the HUDF). This very low value includes a full assessment of the contamination from lower redshift sources, photometric scatter, AGN, spurious sources, low mass stars, and transients (e.g., SNe). From careful modelling of the selection volumes for each of our search fields we derive luminosity functions for galaxies at z~7 and z~8 to <-18 AB mag. The faint-end slopes alpha at z~7 and z~8 are uncertain but very steep at alpha = -2.01+/-0.21 and alpha=-1.91+/-0.32, respectively. Such steep slopes contrast to the local alpha<~-1.4 and may even be steeper than that at z~4 where alpha=-1.73+/-0.05. With such steep slopes (alpha<~-1.7) lower luminosity galaxies dominate the galaxy luminosity density during the epoch of reionization. The star formation rate densities derived from these new z~7 and z~8 luminosity functions are consistent with the trends found at later times (lower redshifts). We find reasonable consistency, with the SFR densities implied from reported stellar mass densities, being only ~40% higher at z<7. This suggests that (1) the stellar mass densities inferred from the Spitzer IRAC photometry are reasonably accurate and (2) that the IMF at very high redshift may not be very different from that at later times.Comment: 38 pages, 21 figures, 20 tables, ApJ, accepted for publicatio

Further developments of the gas electron multiplier (GEM)

We describe the development and operation of the Gas Electron Multiplier, a thin insulating foil metal-clad on both sides and perforated by a regular pattern of small holes. The mesh can be incorporat ed in the gas volume of an active detector to provide a first amplification channel for electrons, or used as stand alone. We report on the basic properties of GEMs manufactured with different geometr ies and operated in several gas mixtures as well as on their long-term stability after accumulation of charge equivalent to several years of operation in high luminosity experiments. Optimized GEMs re ach gains close to 10000 at safe operating voltages, permitting the detection of ionizing tracks, without other amplifying elements, on a simple printed circuit board (PCB), opening new possibilities for detector design

ESO Imaging Survey: infrared observations of CDF-S and HDF-S

This paper presents infrared data obtained from observations carried out at the ESO 3.5m New Technology Telescope (NTT) of the Hubble Deep Field South (HDF-S) and the Chandra Deep Field South (CDF-S). These data were taken as part of the ESO Imaging Survey (EIS) program, a public survey conducted by ESO to promote follow-up observations with the VLT. In the HDF-S field the infrared observations cover an area of ~53 square arcmin, encompassing the HST WFPC2 and STIS fields, in the JHKs passbands. The seeing measured in the final stacked images ranges from 0.79" to 1.22" and the median limiting magnitudes (AB system, 2" aperture, 5sigma detection limit) are J_AB~23.0, H_AB~22.8 and K_AB~23.0 mag. Less complete data are also available in JKs for the adjacent HST NICMOS field. For CDF-S, the infrared observations cover a total area of \~100 square arcmin, reaching median limiting magnitudes (as defined above) of J_AB~23.6 and K_AB~22.7 mag. For one CDF-S field H-band data are also available. This paper describes the observations and presents the results of new reductions carried out entirely through the un-supervised, high-throughput EIS Data Reduction System and its associated EIS/MVM C++-based image processing library developed, over the past 5 years, by the EIS project and now publicly available. The paper also presents source catalogs extracted from the final co-added images which are used to evaluate the scientific quality of the survey products, and hence the performance of the software. This is done comparing the results obtained in the present work with those obtained by other authors from independent data and/or reductions carried out with different software packages and techniques. The final science-grade catalogs and co-added images are available at CDS.Comment: Accepted for publication in A&A, 13 pages, 12 figures; a full resolution version of the paper is available from http://www.astro.ku.dk/~lisbeth/eisdata/papers/4528.pdf ; related catalogs and images are available through http://www.astro.ku.dk/~lisbeth/eisdata

Resistive switching and charge transport mechanisms in ITO/ZnO/p-Si devices

[EN] The resistive switching properties of ITO/ZnO/p-Si devices have been studied, which present well-defined resistance states with more than five orders of magnitude difference in current. Both the high resistance state (HRS) and the low resistance state (LRS) were induced by either sweeping or pulsing the voltage, observing some differences in the HRS. Finally, the charge transport mechanisms dominating the pristine, HRS, and LRS states have been analyzed in depth, and the obtained structural parameters suggest a partial re-oxidation of the conductive nanofilaments and a reduction of the effective conductive area.This work was financially supported by the Spanish Ministry of Economy and Competitiveness (Project Nos. TEC2012-38540-C02-01 and TEC2016-76849-C2-1-R). O.B. also acknowledges the subprogram "Ayudas para Contratos Predoctorales para la Formacion de Doctores" of the Spanish Ministry of Economy and Competitiveness for economical support. X.P., C.L., and C.G. are grateful to C. Frilay for his expertise in the maintenance of the sputtering kit used for the growth of the ZnO films.Blázquez, O.; Frieiro, J.; López-Vidrier, J.; Guillaume, C.; Portier, X.; Labbé, C.; Sanchis Kilders, P.... (2018). Resistive switching and charge transport mechanisms in ITO/ZnO/p-Si devices. Applied Physics Letters. 113(18):1-6. https://doi.org/10.1063/1.50469111611318I. G. Baek , M. S. Lee , S. Sco , M. J. Lee , D. H. Seo , D.S. Suh , J. C. Park , S. O. Park , H. S. Kim , I. K. Yoo , U.I. Chung , and J. T. Moon , in IEDM Technical Digest. IEEE International Electron Devices Meeting, 2004 ( IEEE, 2004), pp. 587–590.Waser, R., & Aono, M. (2007). Nanoionics-based resistive switching memories. Nature Materials, 6(11), 833-840. doi:10.1038/nmat2023Kaeriyama, S., Sakamoto, T., Sunamura, H., Mizuno, M., Kawaura, H., Hasegawa, T., … Aono, M. (2005). A nonvolatile programmable solid-electrolyte nanometer switch. IEEE Journal of Solid-State Circuits, 40(1), 168-176. doi:10.1109/jssc.2004.837244Strukov, D. B., & Likharev, K. K. (2005). CMOL FPGA: a reconfigurable architecture for hybrid digital circuits with two-terminal nanodevices. Nanotechnology, 16(6), 888-900. doi:10.1088/0957-4484/16/6/045Mehonic, A., Cueff, S., Wojdak, M., Hudziak, S., Jambois, O., Labbé, C., … Kenyon, A. J. (2012). Resistive switching in silicon suboxide films. Journal of Applied Physics, 111(7), 074507. doi:10.1063/1.3701581Mehonic, A., Vrajitoarea, A., Cueff, S., Hudziak, S., Howe, H., Labbé, C., … Kenyon, A. J. (2013). Quantum Conductance in Silicon Oxide Resistive Memory Devices. Scientific Reports, 3(1). doi:10.1038/srep02708Pickett, M. D., Medeiros-Ribeiro, G., & Williams, R. S. (2012). A scalable neuristor built with Mott memristors. Nature Materials, 12(2), 114-117. doi:10.1038/nmat3510Jo, S. H., Chang, T., Ebong, I., Bhadviya, B. B., Mazumder, P., & Lu, W. (2010). Nanoscale Memristor Device as Synapse in Neuromorphic Systems. Nano Letters, 10(4), 1297-1301. doi:10.1021/nl904092hVescio, G., Crespo-Yepes, A., Alonso, D., Claramunt, S., Porti, M., Rodriguez, R., … Aymerich, X. (2017). Inkjet Printed HfO2-Based ReRAMs: First Demonstration and Performance Characterization. IEEE Electron Device Letters, 38(4), 457-460. doi:10.1109/led.2017.2668599Valov, I. (2013). Redox-Based Resistive Switching Memories (ReRAMs): Electrochemical Systems at the Atomic Scale. ChemElectroChem, 1(1), 26-36. doi:10.1002/celc.201300165Martín, G., González, M. B., Campabadal, F., Peiró, F., Cornet, A., & Estradé, S. (2017). Transmission electron microscopy assessment of conductive-filament formation in Ni–HfO2–Si resistive-switching operational devices. Applied Physics Express, 11(1), 014101. doi:10.7567/apex.11.014101Simanjuntak, F. M., Panda, D., Wei, K.-H., & Tseng, T.-Y. (2016). Status and Prospects of ZnO-Based Resistive Switching Memory Devices. Nanoscale Research Letters, 11(1). doi:10.1186/s11671-016-1570-yKim, J., & Yong, K. (2011). Mechanism Study of ZnO Nanorod-Bundle Sensors for H2S Gas Sensing. The Journal of Physical Chemistry C, 115(15), 7218-7224. doi:10.1021/jp110129fYuan, Q., Zhao, Y.-P., Li, L., & Wang, T. (2009). Ab Initio Study of ZnO-Based Gas-Sensing Mechanisms: Surface Reconstruction and Charge Transfer. The Journal of Physical Chemistry C, 113(15), 6107-6113. doi:10.1021/jp810161jSeo, J. W., Park, J.-W., Lim, K. S., Yang, J.-H., & Kang, S. J. (2008). Transparent resistive random access memory and its characteristics for nonvolatile resistive switching. Applied Physics Letters, 93(22), 223505. doi:10.1063/1.3041643Rahaman, S. Z., Maikap, S., Chiu, H.-C., Lin, C.-H., Wu, T.-Y., Chen, Y.-S., … Tsai, M.-J. (2010). Bipolar Resistive Switching Memory Using Cu Metallic Filament in Ge[sub 0.4]Se[sub 0.6] Solid Electrolyte. Electrochemical and Solid-State Letters, 13(5), H159. doi:10.1149/1.3339449Simanjuntak, F. M., Panda, D., Tsai, T.-L., Lin, C.-A., Wei, K.-H., & Tseng, T.-Y. (2015). Enhancing the memory window of AZO/ZnO/ITO transparent resistive switching devices by modulating the oxygen vacancy concentration of the top electrode. Journal of Materials Science, 50(21), 6961-6969. doi:10.1007/s10853-015-9247-ySimanjuntak, F. M., Prasad, O. K., Panda, D., Lin, C.-A., Tsai, T.-L., Wei, K.-H., & Tseng, T.-Y. (2016). Impacts of Co doping on ZnO transparent switching memory device characteristics. Applied Physics Letters, 108(18), 183506. doi:10.1063/1.4948598Simanjuntak, F. M., Panda, D., Tsai, T.-L., Lin, C.-A., Wei, K.-H., & Tseng, T.-Y. (2015). Enhanced switching uniformity in AZO/ZnO1−x/ITO transparent resistive memory devices by bipolar double forming. Applied Physics Letters, 107(3), 033505. doi:10.1063/1.4927284Liu, Q., Guan, W., Long, S., Jia, R., Liu, M., & Chen, J. (2008). Resistive switching memory effect of ZrO[sub 2] films with Zr[sup +] implanted. Applied Physics Letters, 92(1), 012117. doi:10.1063/1.2832660Shuai, Y., Zhou, S., Bürger, D., Helm, M., & Schmidt, H. (2011). Nonvolatile bipolar resistive switching in Au/BiFeO3/Pt. Journal of Applied Physics, 109(12), 124117. doi:10.1063/1.3601113Chen, J.-Y., Hsin, C.-L., Huang, C.-W., Chiu, C.-H., Huang, Y.-T., Lin, S.-J., … Chen, L.-J. (2013). Dynamic Evolution of Conducting Nanofilament in Resistive Switching Memories. Nano Letters, 13(8), 3671-3677. doi:10.1021/nl4015638Hubbard, W. A., Kerelsky, A., Jasmin, G., White, E. R., Lodico, J., Mecklenburg, M., & Regan, B. C. (2015). Nanofilament Formation and Regeneration During Cu/Al2O3 Resistive Memory Switching. Nano Letters, 15(6), 3983-3987. doi:10.1021/acs.nanolett.5b00901Liu, Q., Sun, J., Lv, H., Long, S., Yin, K., Wan, N., … Liu, M. (2012). Real-Time Observation on Dynamic Growth/Dissolution of Conductive Filaments in Oxide-Electrolyte-Based ReRAM. Advanced Materials, 24(14), 1844-1849. doi:10.1002/adma.201104104Zhu, X., Wu, H.-Z., Qiu, D.-J., Yuan, Z., Jin, G., Kong, J., & Shen, W. (2010). Photoluminescence and resonant Raman scattering in N-doped ZnO thin films. Optics Communications, 283(13), 2695-2699. doi:10.1016/j.optcom.2010.03.006Cerqueira, M. F., Vasilevskiy, M. I., Oliveira, F., Rolo, A. G., Viseu, T., Ayres de Campos, J., … Correia, R. (2011). Resonant Raman scattering in ZnO:Mn and ZnO:Mn:Al thin films grown by RF sputtering. Journal of Physics: Condensed Matter, 23(33), 334205. doi:10.1088/0953-8984/23/33/334205Marchewka, A., Roesgen, B., Skaja, K., Du, H., Jia, C.-L., Mayer, J., … Menzel, S. (2015). Nanoionic Resistive Switching Memories: On the Physical Nature of the Dynamic Reset Process. Advanced Electronic Materials, 2(1), 1500233. doi:10.1002/aelm.201500233Krzywiecki, M., Grządziel, L., Sarfraz, A., Iqbal, D., Szwajca, A., & Erbe, A. (2015). Zinc oxide as a defect-dominated material in thin films for photovoltaic applications – experimental determination of defect levels, quantification of composition, and construction of band diagram. Physical Chemistry Chemical Physics, 17(15), 10004-10013. doi:10.1039/c5cp00112aMurgatroyd, P. N. (1970). Theory of space-charge-limited current enhanced by Frenkel effect. Journal of Physics D: Applied Physics, 3(2), 151-156. doi:10.1088/0022-3727/3/2/308Electron emission in intense electric fields. (1928). Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character, 119(781), 173-181. doi:10.1098/rspa.1928.0091Özgür, Ü., Alivov, Y. I., Liu, C., Teke, A., Reshchikov, M. A., Doğan, S., … Morkoç, H. (2005). A comprehensive review of ZnO materials and devices. Journal of Applied Physics, 98(4), 041301. doi:10.1063/1.1992666Kaidashev, E. M., Lorenz, M., von Wenckstern, H., Rahm, A., Semmelhack, H.-C., Han, K.-H., … Grundmann, M. (2003). High electron mobility of epitaxial ZnO thin films on c-plane sapphire grown by multistep pulsed-laser deposition. Applied Physics Letters, 82(22), 3901-3903. doi:10.1063/1.1578694Gall, D. (2016). Electron mean free path in elemental metals. Journal of Applied Physics, 119(8), 085101. doi:10.1063/1.4942216Lee, W., Park, J., Kim, S., Woo, J., Shin, J., Choi, G., … Hwang, H. (2012). High Current Density and Nonlinearity Combination of Selection Device Based on TaOx/TiO2/TaOx Structure for One Selector–One Resistor Arrays. ACS Nano, 6(9), 8166-8172. doi:10.1021/nn3028776Kwon, D.-H., Kim, K. M., Jang, J. H., Jeon, J. M., Lee, M. H., Kim, G. H., … Hwang, C. S. (2010). Atomic structure of conducting nanofilaments in TiO2 resistive switching memory. Nature Nanotechnology, 5(2), 148-153. doi:10.1038/nnano.2009.456Choi, B. J., Torrezan, A. C., Strachan, J. P., Kotula, P. G., Lohn, A. J., Marinella, M. J., … Yang, J. J. (2016). High‐Speed and Low‐Energy Nitride Memristors. Advanced Functional Materials, 26(29), 5290-5296. doi:10.1002/adfm.201600680Sun, X. (2006). Designing efficient field emission into ZnO. SPIE Newsroom. doi:10.1117/2.1200602.0101Hu, C., Wang, Q., Bai, S., Xu, M., He, D., Lyu, D., & Qi, J. (2017). The effect of oxygen vacancy on switching mechanism of ZnO resistive switching memory. Applied Physics Letters, 110(7), 073501. doi:10.1063/1.4976512Gul, F., & Efeoglu, H. (2017). Bipolar resistive switching and conduction mechanism of an Al/ZnO/Al-based memristor. Superlattices and Microstructures, 101, 172-179. doi:10.1016/j.spmi.2016.11.043Blázquez, O., Martín, G., Camps, I., Mariscal, A., López-Vidrier, J., Ramírez, J. M., … Garrido, B. (2018). Memristive behaviour of Si-Al oxynitride thin films: the role of oxygen and nitrogen vacancies in the electroforming process. Nanotechnology, 29(23), 235702. doi:10.1088/1361-6528/aab744Bersuker, G., Gilmer, D. C., Veksler, D., Kirsch, P., Vandelli, L., Padovani, A., … Nafría, M. (2011). Metal oxide resistive memory switching mechanism based on conductive filament properties. Journal of Applied Physics, 110(12), 124518. doi:10.1063/1.367156

Estimation of the risk of Salmonella shedding by finishing pigs using a logistic model obtained from a survey

An analytic epidemiological survey was carried out in 105 French farms to identify factors associated with Salmonella shedding by finishing pigs. This study gave out a list of 7 risk factors using a logistic model. The aim of the present survey was to validate this model on a second sample of batches of pigs in order to estimate their Salmonella status. The validation study was carried out from April 2003 to August 2005 on 64 finishing pig batches distinct from those used originally to generate the logistic model. In each farm, Salmonella shedding of a batch of pigs at the end of the finishing phase was assessed using swabs as described in the analytical study. Questionnaires were filled in with the farmer to collect data related to management routines. Blood samples from10 growing and 10 finishing pigs were taken to assess sanitary risk factors: status vs Lawsonia intracellularis and Porcine Respiratory Coronavirus. Salmonella contamination status of a finishing room before loading, a further identified risk factor, was tested by environmental swabbing procedure. The estimated risk with the standard error, of Salmonella shedding was calculated using the logistic model and compared to the bacteriological Salmonella status of each batch. Several thresholds are proposed and sensitivity, specificity, positive and negative predictive values related to each cut-off value were calculated. A cut-off value of 0.34 maximised both sensitivity (76.9%) and specificity (68.6%) of the model. Whatever the threshold, the accuracy of the Salmonella non-shedding predicted status is better than the Salmonella shedding predicted status. In a bacteriological sampling programme, this model could be a useful tool to identify batches with low risk of Salmonella shedding and to focus attention on those getting a high probability for being positive

New observations with the gas electron multiplier (GEM)

We describe recent measurements realized with the Gas Electron Multiplier (GEM) mesh added as pre-amplification element to a multiwire and a micro-strip chamber. Large, stable combined gains are obtained, with good uniformity and energy resolution, in a wide range of filling gases including non-flammable mixtures; coupled to a micro-strip plate, the pre-amplification element allows to maintain the high rate capability and resolution at considerably lower operating voltages, completely eliminating discharge problems. Charge gains are large enough to allow detection of signals in the ionization mode on the last element, permitting the use of a simple printed circuit as read-out electrode; two-dimensional read-out can then be easily implemented. The absence of charge multiplication in the last stage avoids charge build-up on the substrate and prevents ageing phenomena. A new generation of simple, reliable and cheap fast position sensitive detectors seems at hand

Two-dimensional readout of GEM detectors

The recently introduced Gas Electron Multiplier (GEM) permits the amplification of electrons released by ionizing radiation in a gas by factors approaching ten thousand, larger gains can be obtained combining two GEMs in cascade. We describe methods for implementing two- and three-dimensional projective localization of radiation, with sub-millimeter accuracy, making use of specially manufactured and patterned pick-up electrodes. Easy to implement and flexible in the choice of the readout geometry, the technology has the distinctive advantage of allowing all pick-up electrodes to be kept at ground potential, thus substantially improving the system simplicity and reliability. Preliminary results demonstrating the two-dimensional imaging capability of the devices are provided and discussed, as well as future perspectives of development