Dynamical role of system-environment correlations in non-Markovian dynamics

We analyse the role played by system-environment correlations in the emergence of non-Markovian dynamics. By working within the framework developed in Breuer et al., Phys. Rev. Lett. 103, 210401 (2009), we unveil a fundamental connection between non-Markovian behaviour and dynamics of system-environment correlations. We derive an upper bound to the rate of change of the distinguishability between different states of the system that explicitly depends on the development and establishment of correlations between system and environment. We illustrate our results using a fully solvable spin-chain model, which allows us to gain insight on the mechanisms triggering non-Markovian evolution.Comment: 5 pages, 2 figure

Inflation Target Transparency and the Macroeconomy

We quantify the effects of monetary policy transparency and credibility on macroeconomic volatility in an estimated model of the euro area economy. In our model, private agents are unable to distinguish between temporary shocks to the central bank’s monetary policy rule and persistent shifts in the inflation target, and therefore use optimal filtering techniques to construct estimates of the future monetary policy stance. We find that the macroeconomic benefits of credibly announcing the current level of the time-varying inflation target are reasonably small as long as private agents correctly understand the stochastic processes governing the inflation target and the temporary policy shock. If, on the other hand, private agents overestimate the volatility of the inflation target, the overall gains of announcing the target can be substantial. We also show that the central bank to some extent can help private agents in their learning process by responding more aggressively to deviations of inflation from the target.Credibility; Transparency; Inflation targeting; Imperfect information; Private sector learning

Dynamic Control Design LQR PI Vectorial of Remotely Operated Underwater Vehicl

Este Documento muestra el control LQR (Lineal Regulador cuadrático) PI (Integral Proporcional) Diseño vectorial, que está desarrollado para controlar la dinámica de un vehículo submarino operado remotamente ROV, para permitir que el vehículo siga una trayectoria horizontal de forma autónoma. Los resultados se muestran mediante simulaciones de seguimiento de trayectoria de ROV obteniendo resultados satisfactorios y cumpliendo con el objetivo de controlar la dinámica mientras sigue una trayectoria.Universidad Libre -- Facultad de ingeniería -- Ingeniería MecánicaThis Document shows the control LQR (Linear quadratic Regulator) PI (Proportional Integral)Vectorial design, which is developed to control the dynamic of a remote operated underwater vehicle ROV, to allow that the vehicle follow a horizontal trajectory autonomously . The results are showed through simulations of following the trajectory of ROV obtaining satisfactory results and complying with the objective to control the dynamic while follow a trajector

High sporulation and overexpression of virulence factors in biofilms and reduced susceptibility to vancomycin and linezolid in recurrent Clostridium [Clostridioides] difficile infection isolates

Clostridium [Clostridioides] difficile infection (CDI) is one of the leading causes of diarrhea associated with medical care worldwide, and up to 60% of patients with CDI can develop a recurrent infection (R-CDI). A multi-species microbiota biofilm model of C. difficile was designed to evaluate the differences in the production of biofilms, sporulation, susceptibility to drugs, expression of sporulating (sigH, spo0A), quorum sensing (agrD1, and luxS), and adhesion-associated (slpA and cwp84) pathway genes between selected C. difficile isolates from R-CDI and non-recurrent patients (NR-CDI). We obtained 102 C. difficile isolates from 254 patients with confirmed CDI (66 from NR-CDI and 36 from R-CDI). Most of the isolates were biofilm producers, and most of the strains were ribotype 027 (81.374%, 83/102). Most C. difficile isolates were producers of biofilm (100/102), and most were strongly adherent. Sporulation was higher in the R-CDI than in the NR-CDI isolates (p = 0.015). The isolates from R-CDI patients more frequently demonstrated reduced susceptibility to vancomycin than isolates of NR-CDI patients (27.78% [10/36] and 9.09% [6/66], respectively, p = 0.013). The minimum inhibitory concentrations for vancomycin and linezolid against biofilms (BMIC) were up to 100 times and 20 times higher, respectively, than the corresponding planktonic MICs. Expression of sigH, spo0A, cwp84, and agrD1 was higher in R-CDI than in NR-CDI isolates. Most of the C. difficile isolates were producers of biofilms with no correlation with the ribotype. Sporulation was greater in R-CDI than in NR-CDI isolates in the biofilm model of C. difficile. The R-CDI isolates more frequently demonstrated reduced susceptibility to vancomycin and linezolid than the NR-CDI isolates in both planktonic cells and biofilm isolates. A higher expression of sporulating pathway (sigH, spo0A), quorum sensing (agrD1), and adhesion-associated (cwp84) genes was found in R-CDI than in NR-CDI isolates. All of these factors can have effect on the recurrence of the infection.Peer reviewe

Circulation of Highly Drug-Resistant Clostridium difficile Ribotypes 027 and 001 in Two Tertiary-Care Hospitals in Mexico

© 2018, Mary Ann Liebert, Inc.OBJECTIVE: To assess drug susceptibility and characterize Clostridium difficile ribotypes in isolates from two tertiary-care hospitals in Mexico. METHODS: Isolates were evaluated for genotyping, antimicrobial susceptibility testing and detection of mutations associated with drug resistance. PCR ribotyping was performed using a combination of gel-based and capillary electrophoresis-based approaches. RESULTS: MIC50 and MIC90 were ≥128 mg/L for ciprofloxacin, erythromycin, clindamycin, and rifampicin. There was no reduced susceptibility to metronidazole or tetracycline; however, reduced susceptibility to vancomycin (≥4 mg/L) and fidaxomicin (≥2 mg/L) was detected in 50 (40.3%) and 4 (3.2%) isolates, respectively. Furthermore, the rpoB Arg505Lys mutation was more frequently detected in isolates with high minimum inhibitory concentration (MIC) to rifampicin (≥32 mg/L) (OR = 52.5; 95% CI = 5.17-532.6; p < 0.000). Of the 124 C. difficile isolates recovered, 84 (66.7%) were of ribotype 027, 18 (14.5%) of ribotype 001, and the remainder were other ribotypes (353, 255, 220, 208, 176, 106, 076, 020, 019, 017, 014, 012, 003, and 002). CONCLUSION: Ribotypes 027 and 001 were the most frequent C. difficile isolates recovered in this study, and demonstrated higher MICs. Furthermore, we found four isolates with reduced susceptibility to fidaxomicin, raising a concern since this drug is currently unavailable in Mexican Hospitals.Peer reviewedFinal Accepted Versio

Dubious security practices in e-voting schemes Between tech and legal standards

Remote electronic voting has been around for a few decades now. However, some legal uncertainty regarding its uses remains. In this paper, we would like to highlight and discuss several techniques used in e-voting which may not be fully compliant with the law. We analyze several e-voting practices that rely on the addition of dummy ballots and show how they conflict with legal standards. Specifically, we focus on cases where dummy ballots are required for: better performance, testing, participation privacy, or preventing coercion. We argue that these practices may raise issues with the standards of authenticity and eligibility, as well as with the principle “one voter, one vote”. Our research aims to offer a better understanding of how legal principles can be interpreted to ensure the legality of technological proposals in e-voting

The Origin of the Iron-Rich Knot in Tycho's Supernova Remnant

X-ray observations of supernova remnants (SNRs) allow us to investigate the chemical inhomogeneity of ejecta, offering unique insight into the nucleosynthesis in supernova explosions. Here we present detailed imaging and spectroscopic studies of the "Fe knot" located along the eastern rim of the Type Ia SNR Tycho (SN 1572) using Suzaku and Chandra long-exposure data. Surprisingly, the Suzaku spectrum of this knot shows no emission from Cr, Mn, or Ni, which is unusual for the Fe-rich regions in this SNR. Within the framework of the canonical delayed-detonation models for SN Ia, the observed mass ratios M_Cr/M_Fe < 0.023, M_Mn/M_Fe < 0.012, and M_Ni/M_Fe < 0.029 (at 90% confidence) can only be achieved for a peak temperature of (5.3-5.7) x 10^9 K and a neutron excess of < 2.0 x 10^-3. These constraints rule out the deep, dense core of a Chandrasekhar-mass white dwarf as the origin of the Fe knot, and favors either incomplete Si burning or the alpha-rich freeze-out regime, probably close to their boundary. An explosive He burning regime is a possible alternative, although this hypothesis is in conflict with the main properties of this SNR.Comment: 13 pages, 13 figures, accepted for publication in Ap

Corporation effective tax rates and company size: evidence from Germany

We investigate the relationship between the effective tax rate (E.T.R.) and company size in Germany to test tax planning–political power versus political cost theories. In contrast to most studies in this field, which use linear approximations, this paper uses a quantile regression approach. We use data from Compustat, corresponding to non-financial listed companies during 1992–2009. The results indicate a nonlinear relation, with a positive sign for the first quantiles and a negative one in the last part of the distribution. Additionally, leverage, inventory intensity and return on assets are found to be significant determinants of the E.T.R