448 research outputs found

    Experimental Quantification of the Effect of Nonlinearities on the EIS Spectra of the Cathodic Electrode of an Alkaline Electrolyzer

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    [EN] Electrochemical impedance spectroscopy (EIS) is a very powerful tool to study the behavior of electrochemical systems. According to Ohm¿s generalized law, the impedance concept is only valid if the linearity condition is met. In the case that the linearity condition is not achieved, the obtained impedance spectra will present distortions which may lead to biased or even erroneous results and conclusions. In this work, an experimental quantification of the effect of nonlinearities on EIS spectra was performed in order to determine the order of magnitude of the effect of the nonlinearity of the system on the obtained spectra of the cathodic electrode of an alkaline electrolyzer.The authors are very grateful to the Generalitat Valenciana for its economic support in form of Vali+d grant (Ref: ACIF-2013-268).Giner-Sanz, J.; Ortega, E.; Pérez-Herranz, V. (2017). Experimental Quantification of the Effect of Nonlinearities on the EIS Spectra of the Cathodic Electrode of an Alkaline Electrolyzer. Fuel Cells. 17(3):391-401. https://doi.org/10.1002/fuce.201600137S39140117

    Foundations for the Design of a Creative System Based on the Analysis of the Main Techniques that Stimulate Human Creativity

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    This work presents the design of a computational system with creative capacity, based on the synthesis of the main methods that stimulate human creativity. When analyzing each method, a set of characteristics that the computer system must have in order to emulate a creative capacity has been suggested. In this way, by integrating all the suggestions in a structured way, it is possible to design the general architecture and functioning strategy of a computer system that has the incremental creative capacity of well-known creative methods. This computational system is designed as a multi-agent system, made up of two groups of agents, the problem solving group and the creative group, the first one exploring and evaluating paths for suitable solutions, the second implementing creative methods to generate new paths that are provided to the first group

    Renormalization group equations in resonance chiral theory

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    The use of the equations of motion and meson field redefinitions allows the development of a simplified resonance chiral theory lagrangian: terms including resonance fields and a large number of derivatives can be reduced into corresponding O(p2) resonance operators, containing the lowest possible number of derivatives. This is shown by means of the explicit computation of the pion vector form-factor up to next-to-leading order in 1/Nc. The study of the renormalization group equations for the corresponding couplings demonstrates the existence of an infrared fixed point in the resonance theory. The possibility of developing a perturbative 1/Nc expansion in the slow running region around the fixed point is shown here.Comment: 6 pages, 3 figures. Final version as published. References added. Extended explanations. The interrelation between the IR fixed point and the UV constraints has been further studie

    O(p6)O(p^6) extension of the large--NCN_C partial wave dispersion relations

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    Continuing our previous work(JHEP 0706:030,2007), large--NCN_C techniques and partial wave dispersion relations are used to discuss ππ\pi\pi scattering amplitudes. We get a set of predictions for O(p6)O(p^6) low-energy chiral perturbation theory couplings. They are provided in terms of the masses and decay widths of scalar and vector mesons.Comment: 7 page

    Non-stationary Rayleigh-Taylor instability in supernovae ejecta

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    The Rayleigh-Taylor instability plays an important role in the dynamics of several astronomical objects, in particular, in supernovae (SN) evolution. In this paper we develop an analytical approach to study the stability analysis of spherical expansion of the SN ejecta by using a special transformation in the co-moving coordinate frame. We first study a non-stationary spherical expansion of a gas shell under the pressure of a central source. Then we analyze its stability with respect to a no radial, non spherically symmetric perturbation of the of the shell. We consider the case where the polytropic constant of the SN shell is γ=5/3\gamma=5/3 and we examine the evolution of a arbitrary shell perturbation. The dispersion relation is derived. The growth rate of the perturbation is found and its temporal and spatial evolution is discussed. The stability domain depends on the ejecta shell thickness, its acceleration, and the perturbation wavelength.Comment: 16 page

    Consistent response to guselkumab treatment between Hispanic and non-Hispanic patients with psoriasis : an analysis from VOYAGE 1 and VOYAGE 2

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    Altres ajuts: Janssen Research and Development (JRD)Introduction: In VOYAGE 1 (NCT02207231) and VOYAGE 2 (NCT02207244), guselkumab, an interleukin-23 blocker, was safe and effective in patients with moderate-to-severe plaque psoriasis. Methods: Patients who self-identified as Hispanic (n = 117) or non-Hispanic (n = 1686) were randomized to guselkumab, placebo, or adalimumab. Efficacy assessments included Psoriasis Area and Severity Index (PASI), Investigator's Global Assessment (IGA), and Dermatology Life Quality Index (DLQI). Results: At week 16, treatment differences for guselkumab versus placebo in the Hispanic and non-Hispanic populations were 67.4 (95% confidence interval 50.4, 84.4) and 77.2 (73.5, 80.8) percentage points for IGA 0/1 and 59.2 (41.9, 76.4) and 69.2 (65.7, 72.7) percentage points for PASI 90, respectively. Treatment differences for guselkumab versus adalimumab were 25.9 (6.5, 45.3) and 17.5 (12.8, 22.3) percentage points for IGA 0/1 and 21.4 (-0.1, 42.9) and 23.5 (18.2, 28.9) percentage points for PASI 90, respectively. Week 24 results were similar. Adverse event frequency was greater in adalimumab- versus guselkumab-treated patients in the Hispanic population only through weeks 16 and 28. In both populations, DLQI 0/1 responses were greater in guselkumab-treated versus placebo- and adalimumab-treated patients at week 16 and versus adalimumab-treated patients at week 24. Conclusions: Guselkumab safety and efficacy were consistent between Hispanic and non-Hispanic populations

    How to Subvert Backdoored Encryption: Security Against Adversaries that Decrypt All Ciphertexts

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    We study secure and undetectable communication in a world where governments can read all encrypted communications of citizens. We consider a world where the only permitted communication method is via a government-mandated encryption scheme, using government-mandated keys. Citizens caught trying to communicate otherwise (e.g., by encrypting strings which do not appear to be natural language plaintexts) will be arrested. The one guarantee we suppose is that the government-mandated encryption scheme is semantically secure against outsiders: a perhaps advantageous feature to secure communication against foreign entities. But what good is semantic security against an adversary that has the power to decrypt? Even in this pessimistic scenario, we show citizens can communicate securely and undetectably. Informally, there is a protocol between Alice and Bob where they exchange ciphertexts that look innocuous even to someone who knows the secret keys and thus sees the corresponding plaintexts. And yet, in the end, Alice will have transmitted her secret message to Bob. Our security definition requires indistinguishability between unmodified use of the mandated encryption scheme, and conversations using the mandated encryption scheme in a modified way for subliminal communication. Our topics may be thought to fall broadly within the realm of steganography: the science of hiding secret communication in innocent-looking messages, or cover objects. However, we deal with the non-standard setting of adversarial cover object distributions (i.e., a stronger-than-usual adversary). We leverage that our cover objects are ciphertexts of a secure encryption scheme to bypass impossibility results which we show for broader classes of steganographic schemes. We give several constructions of subliminal communication schemes based on any key exchange protocol with random messages (e.g., Diffie-Hellman)

    Some Remarks on the Pade Unitarization of Low-Energy Amplitudes

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    We present a critical analysis of Pade-based methods for the unitarization of low energy amplitudes. We show that the use of certain Pade Approximants to describe the resonance region may lead to inaccurate determinations. In particular, we find that in the Linear Sigma Model the unitarization of the low energy amplitude through the inverse amplitude method produces essentially incorrect results for the mass and width of the sigma. Alternative sequences of Pades are studied and we find that the diagonal sequences (i.e., [N/N]) have much better convergence properties.Comment: 12 pages, 4 fig

    Anaplasmosis outbreak in lambs: First report causing carcass condemnation

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    In spring and summer 2020, six outbreaks of condemnation of jaundiced lamb carcasses were diagnosed in different farms in Aragón region, Spain. Anaplasma ovis was identified in all affected farms. Four hundred and ninety-two lambs from two affected farms were more closely examined. Clinical examination, haematologies, biochemistries, histopathology and microbiological and molecular analyses were performed. After slaughter, 34.84% of the lambs showed jaundiced carcasses and 79.64% presented splenomegaly at the abattoir. All tested lambs with icteric carcasses showed positive A. ovis PCR, although 72.72% of the unaffected lambs also tested positive. However, the bacterial load was significantly higher in the animals that showed jaundiced carcasses (Cq: 25.00 vs 26.16; p = 0.004). Moreover, all the tested lambs that showed severe anaemia were PCR positive. On the contrary, the PCR negative lambs did not show anaemia. Lambs that presented icteric carcasses displayed severe regenerative anaemia with significantly lower erythrocyte count (7.18 vs. 11.97), haematocrit (26.89 vs. 34.82) and haemoglobin (8.50 vs. 11.10) than unaffected lambs. Reticulocyte count (18.80 vs. 5.65) was also significantly increased in affected animals. This article describes a new disorder caused by Anaplasma ovis that is producing significant economic losses associated with the carcass condemnation of apparently healthy lamb
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