Optimal experiment design revisited: fair, precise and minimal tomography

Given an experimental set-up and a fixed number of measurements, how should one take data in order to optimally reconstruct the state of a quantum system? The problem of optimal experiment design (OED) for quantum state tomography was first broached by Kosut et al. [arXiv:quant-ph/0411093v1]. Here we provide efficient numerical algorithms for finding the optimal design, and analytic results for the case of 'minimal tomography'. We also introduce the average OED, which is independent of the state to be reconstructed, and the optimal design for tomography (ODT), which minimizes tomographic bias. We find that these two designs are generally similar. Monte-Carlo simulations confirm the utility of our results for qubits. Finally, we adapt our approach to deal with constrained techniques such as maximum likelihood estimation. We find that these are less amenable to optimization than cruder reconstruction methods, such as linear inversion.Comment: 16 pages, 7 figure

Ray splitting in paraxial optical cavities

We present a numerical investigation of the ray dynamics in a paraxial optical cavity when a ray splitting mechanism is present. The cavity is a conventional two-mirror stable resonator and the ray splitting is achieved by inserting an optical beam splitter perpendicular to the cavity axis. We show that depending on the position of the beam splitter the optical resonator can become unstable and the ray dynamics displays a positive Lyapunov exponent.Comment: 13 pages, 7 figures, 1 tabl

A bridge between the single-photon and squeezed-vacuum state

The two modes of the Einstein-Podolsky-Rosen quadrature entangled state generated by parametric down-conversion interfere on a beam splitter of variable splitting ratio. Detection of a photon in one of the beam splitter output channels heralds preparation of a signal state in the other, which is characterized using homodyne tomography. By controlling the beam splitting ratio, the signal state can be chosen anywhere between the single-photon and squeezed state

Effectiveness of a program of romana’s Pilates for non-specific low back pain: A pilot study

Objetivo: comprobar la efectividad del método Pilates Romana para conseguir una mayor flexibilidad de la columna, junto con una mejora en la movilidad de la misma, así como del dolor que presentan en su vida diaria los pacientes. Metodología: ensayo clínico con intención de tratar a treinta pacientes con dolor lumbar inespecífico. Asistieron a 15 sesiones, 2 veces a la semana, del Método Pilates Romana.. Se evaluaron parámetros tales como dolor, test de Schöber, SRS-22 y distancia dedos- suelo. Resultados. Se encontraron diferencias estadísticamente significativas con respecto al dolor (escala EVA), distancia dedos- suelo, test de Schöber (flexibilidad en plano sagital), flexión lateral (flexibilidad en plano frontal) y en varios ítems de la escala SRS-22, con valores de p<0,001. Por ello, este método puede ser usado para mejorar el dolor, la flexibilidad axial, la función y los aspectos relacionados con la calidad de vidaAim: to test the effectiveness of the Romana’s Pilates method to obtain increased flexibility, improvements in mobility, and reduced pain in daily life. Methodology: a clinical trial with intention-to-treat thirty patients with nonspecific low back pain. Participants attended 15 sessions, twice a week. The Romana’s Pilates method was taught by an external physiotherapist. Parameters such as pain, the Schober test, and the SRS-22 were evaluated. Results: Statistically significant differences in pain (VAS), the Schober test (flexibility in sagittal plane), lateral flexion (flexibility in frontal plane) and several items of the SRS-22 scale were found, with p <0.001. This method may be used to improve pain, axial flexibility, function and aspects related to the quality of life of patient

Influence of culture conditions on the technological properties of Carnobacterium maltaromaticum CNCM I-3298 starters

The aim of this study is to investigate the effect of a broad spectrum of culture conditions on the acidification activity and viability of Carnobacterium maltaromaticum CNCM I‐3298, the main technological properties that determine the shelf‐life of biological time‐temperature integrator (TTI) labels. Cells were cultivated at different temperatures (20–37°C) and pH (6–9·5) according to a modified central composite design and harvested at increasing times up to 10 h of stationary phase. Acidification activity and viability of freeze‐thawed concentrates were assessed in medium mimicking the biological label. Acidification activity was influenced by all three culture conditions, but pH and harvest time were the most influential. Viability was not significantly affected by the tested range of culture conditions.Carnobacterium maltaromaticum CNCM I‐3298 must be cultivated at 20°C, pH 6 and harvested at the beginning of stationary phase to exhibit fastest acidification activities. However, if slower acidification activities are pursued, the recommended culture conditions are 30°C, pH 9·5 and a harvest time between 4–6 h of stationary phase. Quantifying the impact of fermentation temperature, pH and harvest time has led to a predictive model for the production of biological TTI covering a broad range of shelf‐lives

Characterization of immune response to neurofilament light in experimental autoimmune encephalomyelitis

PMCID: PMC3856490This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.PMCID: PMC385649

Linear optics and quantum maps

We present a theoretical analysis of the connection between classical polarization optics and quantum mechanics of two-level systems. First, we review the matrix formalism of classical polarization optics from a quantum information perspective. In this manner the passage from the Stokes-Jones-Mueller description of classical optical processes to the representation of one- and two-qubit quantum operations, becomes straightforward. Second, as a practical application of our classical-\emph{vs}-quantum formalism, we show how two-qubit maximally entangled mixed states (MEMS), can be generated by using polarization and spatial modes of photons generated via spontaneous parametric down conversion.Comment: 13 pages, 8 figure

Depression, Anxiety and Somatic Complaints in Colombian Children Living in Rural Communities

Depresión, ansiedad y síntomas somáticos en niños que viven en comunidades rurales colombianasAbstractIntroduction: In Colombia, children are frequently exposed to traumatic events; however, there are no data regarding the impact on depression, anxiety and somatic correlates of such exposure in children living in rural communities. Objective: To investigate the somatic complaints and symptoms of depression and anxiety among children exposed to traumatic events in a rural community of Colombia. Methods: Design: Cross-Sectional study. Participants: Two hundred and ninety-three Colombian children aged eight to 18 years. Main Outcome Measures: Standardized measures were administered to assess children’s depression, anxiety, physical symptoms and exposure to traumatic events. Depression: CDI (Children’s Depression Inventory); anxiety: SCARED (The Screen for Child Anxiety Related Emotional Disorders); somatic complaints: CBCL (Child Behavior Checklist, Somatic Complaints scale) and reporting traumatic events during the K-SADS-PL (Diagnostic Interview for Children and Adolescents). Results: Ninety-one of the 293 children (31.1%) reported somatic complaints. The most common somatic complaint was in the gastrointestinal category (35/91). One hundred and seventy eight children (60.5%) had observed traumatic events, including homicides during the last month. Two hundred five (69.9%) of the children showed depressive symptom profiles above established norms, and 239 (81.6%) exhibited anxiety symptoms according to their own reports. The correlation between depression and traumatic events, anxiety and somatic complaints, and between anxiety and depression were statistically significant (p&lt;0.005). Conclusions: As the first study of its kind in children living in rural communities in Colombia, it demonstrates a clear impact of traumatic events on mental health. Information that somatic complaints are commonly an expression of underlying depression and anxiety may facilitate the treatment and thereby help avoid unnecessary medical workups and sequelae from traumatized children. It is important for physicians to probe for “hidden” symptoms in traumatized children.Keywords: depression, somatization, traumatic events, anxietyResumenIntroducción: En Colombia, los niños están expuestos con frecuencia a eventos traumáticos, sin embargo, no hay datos sobre el impacto de la depresión, la ansiedad y la correlación somática de dicha exposición en niños que viven en comunidades rurales. Objetivo: investigar las alteraciones somáticas, síntomas de depresión y ansiedad en los niños expuestos a eventos traumáticos en una comunidad rural de Colombia. Metodología: Diseño: Estudio transversal; Participantes: Doscientos noventa y tres niños colombianos de ocho a 18 años. Principales medidas de resultado: se aplicaron medidas estandarizadas para evaluar la depresión infantil, ansiedad, síntomas físicos y la exposición a eventos traumáticos. Depresión:CDI (Children’s Depression Inventory)). Ansiedad: SCARED (The Screen for Child Anxiety Related Emotional Disorders), Enfermedades somáticas: CBCL (Child Behavior Checklist, Somatic Complaints scale) e informar los eventos traumáticos durante el K -SADS -PL (Diagnostic Interview for Children and Adolescents). Resultados: Noventa y uno de los 293 niños ( 31,1 % ) informaron de síntomas somáticos. La queja somática más común estuvo en la categoría gastrointestinal (35/ 91). Ciento setenta y ocho niños ( 60,5 % ) habían observado los acontecimientos traumáticos, incluyendo homicidios durante el último mes. Doscientos cinco ( 69,9 % ) de los niños mostraron perfiles de síntomas depresivos por encima de las normas establecidas, y 239 ( 81,6 % ) presentaban síntomas de ansiedad según sus propios informes. La correlación entre la depresión y los eventos traumáticos, la ansiedad y quejas somáticas, y entre la ansiedad y la depresión fueron estadísticamente significativas ( p &lt; 0,005 ). Conclusiones: como el primer estudio de su tipo en los niños que viven en comunidades rurales de Colombia , demuestra un claro impacto de eventos traumáticos en la salud mental. La afirmación que las quejas somáticas son comúnmente una expresión de la depresión y la ansiedad subyacente puede facilitar el tratamiento y de ese modo ayudar a evitar abordajes médicos innecesarios y secuelas en los niños traumatizados . Es importante para los médicos explorar los síntomas “ocultos” en los niños traumatizados.Palabras Clave: depresión, somatización, evento traumático, ansieda