Obtención de las soluciones periódicas de un oscilador no lineal mediante un método rápido de Galerkin

Este artículo está enfocado a la determinación de las soluciones periódicas de los osciladores no lineales así como al análisis cualitativo de su estabilidad. Estos osciladores están modelizados por la ecuación diferencial 3 Z ( t ) + kk(t) + E ajzj = g(t) j=1 siendo g(t) una fuerza T-periódica. En este trabajo desarrollamos un algoritmo basado en el método de Galerkin que utiliza la transformada rápida de Fourier (FFT) para calcular las soluciones periódicas de la ecuación anterior. Además, incluimos un algoritmo combinado en un apéndice, con convergencia rápida, para resolver las ecuaciones algebraicas no lineales obtenidas por dicho método. Finalmente, validamos esta metodología aplicando el algoritmo pa,ra obtener las soluciones periódicas de un oscilador de Duffing con comportamiento caótico.This paper is focused to the determination of the harmonic solutions of the non linear oscillators modelled by the following differential equation 3 Z (t) + kk (t) + E a, r' = g (t) j=l being g(t) a T-periodic driving force. In this work we develop an algorithm based on the Galerkin method, using the Fast Fourier Transform (FFT) to calculate the harmonic solutions of previous equation. Furthermore, we include a combined algorithm with fast convergence to solve the non linear algebraic equations obtained in the Galerkin Fast Algorithm. Finally, we validate this methodology applying the algorithm to obtain the harmonic solutions of a Duffing oscillator with a chaotic behavior.Peer Reviewe

Associations of serum phthalate metabolites with thyroid hormones in GraMo cohort, Southern Spain

These results would not have been achieved without the selfless collaboration of the staff from Santa Ana and San Cecilio Hospitals and the participants who took part in the study. Dr. JP Arrebola is under contract within the Ramon y Cajal Program (RYC-2016-20155, Ministerio de Economia, Industria y Competitividad, Spain) and Dr. C Donat-Vargas is under contract within the Atraccion de Talento (from the community of Madrid, Spain) . This study was supported by research grants from Instituto de Salud Carlos III (PI20/01568, PI16/01858) .The general population is continuously exposed to phthalates via various consumer products. Epidemiological research relating phthalate exposure to thyroid function during non-developmental periods is limited. This study aimed to investigate the associations between specific serum phthalate metabolites and indicators of thyroid function in adults. We measured 10 serum phthalate metabolites and thyroid hormones - total triiodothymnine (TT3), free thyroxine (FT4) and thyroid stimulating hormone (TSH) - in a subsample of 207 adults from the GraMo cohort. This subsample was made up of men and women (in equal proportions) of middle age (49 +/- 17 years) and from Southern Spain (province of Granada). Data on age, sex, body mass index, residence area, tobacco use, alcohol consumption and attained education were obtained from a questionnaire. Phthalate metabolites were log-transformed and categorized into tertiles. Cross-sectional associations of each metabolite with thyroid hormones were analyzed using multivariable-adjusted linear regression models. The mixture effect of metabolite phthalates was assessed using weighted quantile sum regression. After multivariable-adjustment, the following phthalate metabolites were significantly associated with TT3 in a dose-response manner: MMP (beta = 0.90: 95% confidence interval 0.68,1.12), MEP (beta = 0.67: 0.44, 0.90), MiBP (beta = 0.49: 0.21, 0.77), MiDP (beta = 0.27: 0.03, 0.52), MBzP (beta = 0.51: 0.28, 0.73), MEHP (beta = -0.59: -0.82, -0.35) and MiNP (beta = -0.43: -0.71, -0.14), when comparing highest vs. lowest exposed. The sum of all metabolites was also linked to FT4 levels. No significant associations were observed for TSH except for MiNP. Although phthalate metabolites with different molecular weight showed opposite associations, overall metabolite concentrations seem to associate with increased TT3 and FT4 serum levels. The cross-sectional nature of this analysis limits causal inference.Ramon y Cajal Program (Ministerio de Economia, Industria y Competitividad, Spain) RYC-2016-20155Instituto de Salud Carlos III European Commission PI20/01568 PI16/0185

Biological Markers of Pseudomonas aeruginosa Epidemic High-Risk Clones

A limited number of Pseudomonas aeruginosa genotypes (mainly ST-111, ST-175, and ST-235), known as high-risk clones, are responsible for epidemics of nosocomial infections by multidrug-resistant (MDR) or extensively drug-resistant (XDR) strains worldwide. We explored the potential biological parameters that may explain the success of these clones. A total of 20 isolates from each of 4 resistance groups (XDR, MDR, ModR [resistant to 1 or 2 classes], and MultiS [susceptible to all antipseudomonals]), recovered from a multicenter study of P. aeruginosa bloodstream infections performed in 10 Spanish hospitals, were analyzed. A further set of 20 XDR isolates belonging to epidemic high-risk clones (ST-175 [n = 6], ST-111 [n = 7], and ST-235 [n = 7]) recovered from different geographical locations was also studied. When unknown, genotypes were documented through multilocus sequence typing. The biological parameters evaluated included twitching, swimming, and swarming motility, biofilm formation, production of pyoverdine and pyocyanin, spontaneous mutant frequencies, and the in vitro competition index (CI) obtained with a flow cytometry assay. All 20 (100%) XDR, 8 (40%) MDR, and 1 (5%) ModR bloodstream isolate from the multicenter study belonged to high-risk clones. No significant differences were observed between clonally diverse ModR and MultiS isolates for any of the parameters. In contrast, MDR/XDR high-risk clones showed significantly increased biofilm formation and mutant frequencies but significantly reduced motility (twitching, swimming, and swarming), production of pyoverdine and pyocyanin, and fitness. The defined biological markers of high-risk clones, which resemble those resulting from adaptation to chronic infections, could be useful for the design of specific treatment and infection control strategies

A large sustained endemic outbreak of multiresistant Pseudomonas aeruginosa: a new epidemiological scenario for nosocomial acquisition

Background: Studies of recent hospital outbreaks caused by multiresistant P.aeruginosa (MRPA) have often failed to identify a specific environmental reservoir. We describe an outbreak due to a single clone of multiresistant (MR) Pseudomonas aeruginosa (PA) and evaluate the effectiveness of the surveillance procedures and control measures applied. Methods: Patients with MRPA isolates were prospectively identified (January 2006-May 2008). A combined surveillance procedure (environmental survey, and active surveillance program in intensive care units [ICUs]) and an infection control strategy (closure of ICU and urology wards for decontamination, strict compliance with cross-transmission prevention protocols, and a program restricting the use of carbapenems in the ICUs) was designed and implemented. Results: Three hundred and ninety patients were identified. ICU patients were the most numerous group (22%) followed by urology patients (18%). Environmental surveillance found that 3/19 (16%) non-ICU environmental samples and 4/63 (6%) ICU samples were positive for the MRPA clonal strain. In addition, active surveillance found that 19% of patients were fecal carriers of MRPA. Significant changes in the trends of incidence rates were noted after intervention 1 (reinforcement of cleaning procedures): -1.16 cases/1,000 patient-days (95%CI -1.86 to -0.46; p = 0.003) and intervention 2 (extensive decontamination): -1.36 cases/1,000 patient-days (95%CI -1.88 to -0.84; p < 0.001) in urology wards. In addition, restricted use of carbapenems was initiated in ICUs (January 2007), and their administration decreased from 190-170 DDD/1,000 patient-days (October-December 2006) to 40-60 DDD/1,000 patient-days (January-April 2007), with a reduction from 3.1 cases/1,000 patient-days in December 2006 to 2.0 cases/1,000 patient-days in May 2007. The level of initial carbapenem use rose again during 2008, and the incidence of MRPA increased progressively once more. Conclusions: In the setting of sustained MRPA outbreaks, epidemiological findings suggest that patients may be a reservoir for further environmental contamination and cross-transmission. Although our control program was not successful in ending the outbreak, we think that our experience provides useful guidance for future approaches to this problem

Epidemiological trends of HIV/HCV coinfection in Spain, 2015-2019

Altres ajuts: Spanish AIDS Research Network; European Funding for Regional Development (FEDER).Objectives: We assessed the prevalence of anti-hepatitis C virus (HCV) antibodies and active HCV infection (HCV-RNA-positive) in people living with HIV (PLWH) in Spain in 2019 and compared the results with those of four similar studies performed during 2015-2018. Methods: The study was performed in 41 centres. Sample size was estimated for an accuracy of 1%. Patients were selected by random sampling with proportional allocation. Results: The reference population comprised 41 973 PLWH, and the sample size was 1325. HCV serostatus was known in 1316 PLWH (99.3%), of whom 376 (28.6%) were HCV antibody (Ab)-positive (78.7% were prior injection drug users); 29 were HCV-RNA-positive (2.2%). Of the 29 HCV-RNA-positive PLWH, infection was chronic in 24, it was acute/recent in one, and it was of unknown duration in four. Cirrhosis was present in 71 (5.4%) PLWH overall, three (10.3%) HCV-RNA-positive patients and 68 (23.4%) of those who cleared HCV after anti-HCV therapy (p = 0.04). The prevalence of anti-HCV antibodies decreased steadily from 37.7% in 2015 to 28.6% in 2019 (p < 0.001); the prevalence of active HCV infection decreased from 22.1% in 2015 to 2.2% in 2019 (p < 0.001). Uptake of anti-HCV treatment increased from 53.9% in 2015 to 95.0% in 2019 (p < 0.001). Conclusions: In Spain, the prevalence of active HCV infection among PLWH at the end of 2019 was 2.2%, i.e. 90.0% lower than in 2015. Increased exposure to DAAs was probably the main reason for this sharp reduction. Despite the high coverage of treatment with direct-acting antiviral agents, HCV-related cirrhosis remains significant in this population

Feynman-alpha and Rossi-alpha formulas with spatial and modal effects

[EN] Feynman-α and Rossi-α formulas including multiple α-modes are derived for stochastic and continuous neutron sources. The presented formalism is further developed to achieve spatial correction factors for the single α-mode point kinetics representations of the Feynman-α and Rossi-α formulas. As a natural extension of the multiple α-mode formalism, delayed neutrons are included in the Feynman-α formula. The obtained formulas are validated experimentally in a strongly heterogeneous system obeying multiple α-modes, resulting in good agreement with the presented theoretical framework.This work was supported by IP-EUROTRANS contract no. FI6W-CT2005-516520, the ENRESA-CIEMAT agreement for the Transmutacion Aplicada a los Residuos Radiactivos de Alta Actividad, Svensk Karnbranslehantering AB (SKB, the Swedish Nuclear Fuel and Waste Management Co) and the Swedish Institute through the Visby program.Muñoz-Cobo González, JL.; Berglöt, C.; Peña Miralles, J.; Villamarín, D.; Bournos, V. (2011). Feynman-alpha and Rossi-alpha formulas with spatial and modal effects. Annals of Nuclear Energy. 38(2-3):590-600. doi:10.1016/j.anucene.2010.09.27S590600382-

Obtención de las soluciones periódicas de un oscilador no lineal mediante un método rápido de Galerkin

Este artículo está enfocado a la determinación de las soluciones periódicas de los osciladores no lineales así como al análisis cualitativo de su estabilidad. Estos osciladores están modelizados por la ecuación diferencial 3 Z ( t ) + kk(t) + E ajzj = g(t) j=1 siendo g(t) una fuerza T-periódica. En este trabajo desarrollamos un algoritmo basado en el método de Galerkin que utiliza la transformada rápida de Fourier (FFT) para calcular las soluciones periódicas de la ecuación anterior. Además, incluimos un algoritmo combinado en un apéndice, con convergencia rápida, para resolver las ecuaciones algebraicas no lineales obtenidas por dicho método. Finalmente, validamos esta metodología aplicando el algoritmo pa,ra obtener las soluciones periódicas de un oscilador de Duffing con comportamiento caótico.This paper is focused to the determination of the harmonic solutions of the non linear oscillators modelled by the following differential equation 3 Z (t) + kk (t) + E a, r' = g (t) j=l being g(t) a T-periodic driving force. In this work we develop an algorithm based on the Galerkin method, using the Fast Fourier Transform (FFT) to calculate the harmonic solutions of previous equation. Furthermore, we include a combined algorithm with fast convergence to solve the non linear algebraic equations obtained in the Galerkin Fast Algorithm. Finally, we validate this methodology applying the algorithm to obtain the harmonic solutions of a Duffing oscillator with a chaotic behavior.Peer Reviewe

Performance of TerraSAR-X for urban subsidence monitoring: Murcia case study

This paper presents an analysis of the performance of TerraSAR-X for subsidence monitoring in urban areas. The city of Murcia has been selected as a test-site due to its high deformation rate and the set of extensometers deployed along the city that provide validation data. The obtained results have been compared with those obtained from ERS/ENVISAT data belonging to the same period and validated with the in-situ measurements.This work has been supported by the Spanish MICINN and European Union FEDER funds under project TEC2008-06764-C02. The TerraSAR-X images were provided by DLR in the framework of the scientific project GEO0389. ERS and ENVISAT data were provided by ESA in the framework of the CAT11 project 2494