892 research outputs found
Equivalence regimes for geometric quantum discord and local quantum uncertainty
The concept of quantum discord aims at unveiling quantum correlations that go beyond those described by entanglement. Its original formulation [L. Henderson and V. Vedral, J. Phys. A: Math. Gen. 34, 6899 (2001); H. Ollivier and W. H. Zurek, Phys. Rev. Lett. 88, 017901 (2001)] is difficult to compute even for the simplest case of two-qubits systems. Alternative formulations have been developed to address this drawback, such as the geometric measure of quantum discord [L. Chang and S. Luo, Phys. Rev. A 87, 062303 (2013)] and the local quantum uncertainty [D. Girolami, T. Tufarelli, and G. Adesso, Phys. Rev. Lett. 110, 240402 (2013)] that can be evaluated in closed form for some quantum systems, such as two-qubit systems. We show here that these two measures of quantum discord are equivalent for 2×D dimensional bipartite quantum systems. By considering the relevant example of N00N states for phase estimation in lossy environments, we also show that both metrics of quantum discord quantify the decrease of quantum Fisher information of the phase estimation protocol. Given their ease of computation in 2×D bipartite systems, the geometric measure of quantum discord and the local quantum uncertainty demonstrate their relevance as computable measures of quantum discord.We acknowledge support from the Spanish Ministry of
Economy and Competitiveness (“Severo Ochoa” program
for Centres of Excellence in R&D No. SEV-2015-0522),
from Fundacio Privada Cellex, from Fundacio Mir-Puig, and
from Generalitat de Catalunya through the CERCA program.
This work was partially funded through the EMPIR
project 17FUN01-BeCOMe. The EMPIR initiative is cofunded
by the European Union Horizon 2020 Research and
Innovation Programme and the EMPIR participating states.
A.V. acknowledges financial support from PREBIST that
has received funding from the European Union Horizon
2020 Research and Innovation Programme under the Marie
Sklodowska-Curie Grant Agreement No. 754558. J.R.A. acknowledges
funding by the European Union Horizon 2020
Research and Innovation Programme (Marie Sklodowska-
Curie 765075-LIMQUET). R.J.L.M. thankfully acknowledges
financial support by CONACyT under the project
CB-2016-01/284372, and by Direcci n General de Asuntos
del Personal Acad mico, Universidad Nacional Aut noma de
M xico (DGAPA-UNAM), under the project UNAM-PAPIIT
IN102920.Peer ReviewedPostprint (author's final draft
Genotyping of Leptospira interrogans isolates from Mexican patients
The aim of this study was genotypically characterize Leptospira sp. clinical isolates from Mexico which were previously identified as Leptospira interrogans serovar Pomona (POM) by phenotypic methods. The Random Amplified Polymorphic DNA (RAPD) method was used for DNA amplification with five oligonucleotides. A dendrogram was constructed using the Unweighted Pair Group Method Analysis (UPGMA). During the genotypic characterization, the studied isolates constituted a group which was associated with the reference strain L. interrogans serovar Pomona. The Minimum Spanning Networks (MST) analysis revealed the same cluster between Mexican isolates and the reference strain POM. Clinical isolates identified as L. interrogans serovar POM have a clonal reproduction type, suggesting that this clone is distributed in different regions of Mexico
SELECCIÓN DE ÁNGULOS DE CONMUTACIÓN PARA UN INVERSOR MULTINIVEL EN CASCADA USANDO UN ALGORITMO DE BÚSQUEDA ALEATORIA (SWITCHING ANGLES SELECTION FOR A CASCADED MULTILEVEL INVERTER USING A RANDOM SEARCH ALGORITHM)
Resumen
Un inversor de cascada trifásico H-Bridge de varios niveles en condiciones de fallo de un solo interruptor puede funcionar como un inversor asimétrico aplicando un cambio en la estrategia de modulación para mejorar su rendimiento. Este documento presenta el Algoritmo de Búsqueda Aleatoria aplicado a la modulación de Eliminación Selectiva de Armónicos para Inversores de Cascada Multinivel Asimétricos. El algoritmo propuesto tiene por objeto encontrar una solución óptima a un conjunto de ecuaciones trascendentales, que garantizan la eliminación de armónicos no deseados y el control de la magnitud de la componente fundamental de la tensión generada por el inversor. Además, el algoritmo propuesto se comparó con el algoritmo de optimización de enjambre de partículas y la estrategia tradicional de eliminación selectiva de armónicos. Los resultados comparativos obtenidos mostraron que la técnica de modulación que usa la técnica Algoritmo de Búsqueda Aleatoria es la más adecuada para el inversor multinivel trifásico de siete niveles (caso de estudio).
Palabras Clave: Algoritmo de búsqueda aleatoria, Eliminación selectiva de armónicos, Estrategia de tolerancia a fallos, Inversor de modulación de ancho de pulso, Inversor multinivel.
Abstract
A three-phase H-Bridge multi-level cascade inverter under Single-Switch Fault Condition can operate as an asymmetrical inverter by applying a change in the modulation strategy to improve its performance. This paper presents the Random Search Algorithm applied to the modulation of Selective Harmonic Elimination for Asymmetric Cascade Multilevel Inverters. The proposed algorithm aims to find an optimal solution to a set of transcendental equations, which guarantee the elimination of undesired harmonics and controlling the magnitude of the fundamental component of the voltage generated by the inverter. In addition, the proposed algorithm was compared with the Particle Swarm Optimization algorithm and the traditional selective harmonic elimination strategy. The comparative results obtained showed that the modulation technique using the Random Search Algorithm technique is the most suitable for the seven-level three-phase multilevel inverter (case study).
Keywords: Fault Tolerant Strategy, Pulse Width Modulation inverter, Random Search Algorithm, Selective Harmonic Elimination, Multilevel inverter
Noise-assisted energy transport in electrical oscillator networks with off-diagonal dynamical disorder
Noise is generally thought as detrimental for energy transport in coupled oscillator networks. However, it has been shown that for certain coherently evolving systems, the presence of noise can enhance, somehow unexpectedly, their transport efficiency; a phenomenon called environment-assisted quantum transport (ENAQT) or dephasing-assisted transport. Here, we report on the experimental observation of such effect in a network of coupled electrical oscillators. We demonstrate that by introducing stochastic fluctuations in one of the couplings of the network, a relative enhancement in the energy transport efficiency of 22.5 ± 3.6% can be observed.Peer ReviewedPostprint (published version
Distribución actualizada del género Cerambyx Linnaeus, 1758 (Coleoptera: Cerambycidae) en Extremadura: desde los registros históricos al muestreo a escala regional
The genus Cerambyx (Coleoptera: Cerambycidae) includes 13 species with a western Palaearctic distribution, seven present in Europe and four in the Iberian Peninsula, all of them also recorded in Extremadura: C. cerdo Linnaeus, 1758, C. welensii (Küster, 1845), C. miles Bonelli, 1812 and C. scopolii Fuessly, 1775. Larvae are primary xylophagous, tunnelling the living wood of healthy or decayed trees. Like other cerambycids, they are included in the diverse assemblage of saproxylic insects, a functional group essential in wood degradation and biodiversity enhancement. They have also been reported as pests, being able to cause significant physiological, mechanical and structural damages. The impact of xylophagous on oaks in Extremadura has increased alarmingly in recent decades. Damages have usually been attributed to C. welensii, but accumulated evidence shows that this statu quo is unrealistic, and that C. cerdo is also involved in oak decline. The scarce chorological information available prevents risk analysis of the potential impact of these species, being necessary a detailed knowledge of their regional distribution. Thus, 1826 feeding traps (Regional Sampling Network) were placed throughout Extremadura over five years (2017-2021) during May-August in holm oak, cork oak and pyrenean oakwoodlands. Traps covered 437 10 × 10 km UTM squares representing an equivalent sampled area of 40,430 km2 (97% of Extremadura). Trap records were completed with other unpublished and bibliographic records. The data showed: 1) that records prior to 1980s were occasional, 2) that C. miles and C. scopolii are rare and localized species, 3) that C. welensii is a ubiquitous species, consistent with its pest status, 4) that C. cerdo exhibits a widespread and often abundant distribution, and 5) that distribution and population sizes depended on host tree, highlighting that C. welensii was almost 5 times more abundant than C. cerdo in cork oak, and that C. cerdo was 3-4 times more abundant in holm oak than in cork oak or pyrenean oak. Results indicate that damage by large xylophagous in Extremadura oak open woodlands is caused by both C. welensii and C. cerdo, refute that C. cerdo is a rare and threatened species in the region, and suggest that the Habitats Directive requires an urgent reappraisal in order to eliminate or mitigate the conflict of interests between the protection of C. cerdo and that of the dehesa ecosystem in Extremadura.El género Cerambyx (Coleoptera: Cerambycidae) incluye 13 especies con distribución paleártica occidental, siete presentes en Europa y cuatro en la Península Ibérica, todas ellas también registradas en Extremadura: C. cerdo Linnaeus, 1758, C. welensii (Küster, 1845), C. miles Bonelli, 1812 y C. scopolii Fuessly, 1775. Las larvas son xilófagas primarias, perforando la madera viva de árboles sanos o decaídos. Como otros cerambícidos, se incluyen en el diverso ensamble de insectos saproxílicos, un grupo funcional esencial en la degradación de la madera y la potenciación de la biodiversidad. También se han descrito como plagas, pudiendo provocar importantes daños fisiológicos, mecánicos y estructurales. El impacto de los xilófagos en las quercíneas extremeñas ha aumentado alarmantemente en las últimas décadas. Los daños se han atribuido usualmente a C. welensii, pero la evidencia acumulada muestra que este statu quo no es realista, y que C. cerdo contribuye igualmente al decaimiento del arbolado. La escasa información corológica disponible impide efectuar análisis de riesgos del impacto potencial de dichas especies, siendo necesario un conocimiento detallado de su distribución regional. Así, se dispusieron 1826 trampas alimenticias (Red Regional de Muestreo) por toda Extremadura a lo largo de cincoaños (2017-2021) durante mayo-agosto en dehesas de encina, alcornoque y melojo. Las trampas cubrieron 437 cuadrículas UTM de 10 × 10 km con una superficie equivalente muestreada de 40.430 km2 (97% de Extremadura). Los registros de las trampas se completaron con otros registros inéditos y bibliográficos. Los datos mostraron: 1) que los registros anteriores a 1980s fueron ocasionales, 2) que C. miles y C. scopolii son especies escasas y localizadas, 3) que C. welensii es una especie ubicua, consistente con su estatus de plaga, 4) que C. cerdo exhibe una distribución generalizada y a menudo abundante, y 5) que la distribución y efectivos poblacionales dependieron del árbol hospedador, destacando que C. welensii fue casi 5 veces más abundante que C. cerdo en alcornoque, y que C. cerdo fue 3-4 veces más abundante en encina que en alcornoque o melojo. Los resultados indican que los daños por grandes xilófagos en las dehesas extremeñas tienen como agente causal tanto a C. welensii como a C. cerdo, refutan que C. cerdo es una especie rara y amenazada en la región, y sugieren que la Directiva Hábitats requiere una revisión urgente con el objetivo de eliminar o mitigar el conflicto de intereses entre la protección de C. cerdo y la del ecosistema de dehesa en Extremadura
Epidemiology of human papillomavirus-related oropharyngeal cancer in a classically low-burden region of southern Europe
The incidence of human papillomavirus (HPV)-related oropharyngeal cancer is increasing in some regions. Nevertheless, the epidemiology of this disease has not been extensively investigated in southern Europe. We conducted a retrospective cohort study of patients diagnosed with primary oropharyngeal cancer from 1991 to 2016. Cancer tissues underwent histopathological evaluation, DNA quality control, HPV-DNA detection and p16 immunohistochemistry. Data were collected from medical records. Factors associated with HPV positivity and time trends were evaluated with multivariable Bayesian models. The adjusted prevalence of HPV-related cases in 864 patients with a valid HPV-DNA result was 9.7%, with HPV-DNA/p16 double positivity being considered. HPV-related oropharyngeal cancer was likely to occur in non-smokers and non-drinkers, to be located in the tonsil or diagnosed at advanced stages. Time-trend analysis showed an increasing risk of HPV-related oropharyngeal cancer in the most recent periods (5-year period increase of 30%). This increase was highest and with a clear increasing trend only in the most recent years (2012-2016). The prevalence of HPV-related oropharyngeal cancer started to sharply increase in the most recent years in our setting, as occurred two decades ago in areas where most oropharyngeal cancer cases are currently HPV-related. Our results provide a comprehensive assessment of the epidemiological landscape of HPV-related oropharyngeal cancer in a region of southern Europe
Negative symptoms and sex differences in first episode schizophrenia: What's their role in the functional outcome? A longitudinal study
Introduction: Negative symptoms (NS) include asociality, avolition, anhedonia, alogia, and blunted affect and are linked to poor prognosis. It has been suggested that they reflect two different factors: diminished expression (EXP) (blunted affect and alogia) and amotivation/pleasure (MAP) (anhedonia, avolition, asociality). The aim of this article was to examine potential sex differences among first-episode schizophrenia (FES) patients and analyze sex-related predictors of two NS symptoms factors (EXP and MAP) and functional outcome. Material and methods: Two hundred and twenty-three FES (71 females and 152 males) were included and evaluated at baseline, six-months and one-year. Repeated measures ANOVA was used to examine the effects of time and sex on NS and a multiple linear regression backward elimination was performed to predict NS factors (MAP-EXP) and functioning. Results: Females showed fewer NS (p = 0.031; Cohen's d = −0.312), especially those related to EXP (p = 0.024; Cohen's d = −0.326) rather than MAP (p = 0.086), than males. In both male and female group, worse premorbid adjustment and higher depressive symptoms made a significant contribution to the presence of higher deficits in EXP at one-year follow-up, while positive and depressive symptoms predicted alterations in MAP. Finally, in females, lower deficits in MAP and better premorbid adjustment predicted better functioning at one-year follow-up (R2 = 0.494; p < 0.001), while only higher deficits in MAP predicted worse functioning in males (R2 = 0.088; p = 0.012). Conclusions: Slightly sex differences have been found in this study. Our results lead us to consider that early interventions of NS, especially those focusing on motivation and pleasure symptoms, could improve functional outcomes
Effectiveness of an intervention for improving drug prescription in primary care patients with multimorbidity and polypharmacy:Study protocol of a cluster randomized clinical trial (Multi-PAP project)
This study was funded by the Fondo de Investigaciones Sanitarias ISCIII (Grant Numbers PI15/00276, PI15/00572, PI15/00996), REDISSEC (Project Numbers RD12/0001/0012, RD16/0001/0005), and the European Regional Development Fund ("A way to build Europe").Background: Multimorbidity is associated with negative effects both on people's health and on healthcare systems. A key problem linked to multimorbidity is polypharmacy, which in turn is associated with increased risk of partly preventable adverse effects, including mortality. The Ariadne principles describe a model of care based on a thorough assessment of diseases, treatments (and potential interactions), clinical status, context and preferences of patients with multimorbidity, with the aim of prioritizing and sharing realistic treatment goals that guide an individualized management. The aim of this study is to evaluate the effectiveness of a complex intervention that implements the Ariadne principles in a population of young-old patients with multimorbidity and polypharmacy. The intervention seeks to improve the appropriateness of prescribing in primary care (PC), as measured by the medication appropriateness index (MAI) score at 6 and 12months, as compared with usual care. Methods/Design: Design:pragmatic cluster randomized clinical trial. Unit of randomization: family physician (FP). Unit of analysis: patient. Scope: PC health centres in three autonomous communities: Aragon, Madrid, and Andalusia (Spain). Population: patients aged 65-74years with multimorbidity (≥3 chronic diseases) and polypharmacy (≥5 drugs prescribed in ≥3months). Sample size: n=400 (200 per study arm). Intervention: complex intervention based on the implementation of the Ariadne principles with two components: (1) FP training and (2) FP-patient interview. Outcomes: MAI score, health services use, quality of life (Euroqol 5D-5L), pharmacotherapy and adherence to treatment (Morisky-Green, Haynes-Sackett), and clinical and socio-demographic variables. Statistical analysis: primary outcome is the difference in MAI score between T0 and T1 and corresponding 95% confidence interval. Adjustment for confounding factors will be performed by multilevel analysis. All analyses will be carried out in accordance with the intention-to-treat principle. Discussion: It is essential to provide evidence concerning interventions on PC patients with polypharmacy and multimorbidity, conducted in the context of routine clinical practice, and involving young-old patients with significant potential for preventing negative health outcomes. Trial registration: Clinicaltrials.gov, NCT02866799Publisher PDFPeer reviewe
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