1,472 research outputs found

    Coherence properties of coupled optomechanical cavities

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    In this work we investigate an optomechanical system consisting of two cavities coupled to the same mechanical resonator. We consider each cavity being weakly pumped as well as a small tunneling rate between the cavities. In such conditions, the system can be studied via quantum Langevin equations and the steady state solution can be found perturbatively. In order to ensure that the approximations and methods used to study the system are suitable, the analytical results were compared to numerical simulations. We study the statistical properties of the cavity radiation fields and we show that depending on the values of the parameters of the system, it is possible to modify the spectrum of the cavities and even enhance the sub-Poissonian character of the cavity field.Comment: 8 pages, 6 figure

    Engineering Fast High-Fidelity Quantum Operations With Constrained Interactions

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    Understanding how to tailor quantum dynamics to achieve a desired evolution is a crucial problemin almost all quantum technologies. We present a very general method for designing high-efficiencycontrol sequences that are always fully compatible with experimental constraints on available inter-actions and their tunability. Our approach reduces in the end to finding control fields by solvinga set of time-independent linear equations. We illustrate our method by applying it to a numberof physically-relevant problems: the strong-driving limit of a two-level system, fast squeezing in aparametrically driven cavity, the leakage problem in transmon qubit gates, and the acceleration ofSNAP gates in a qubit-cavity system

    Nanoscale mapping and control of antenna-coupling strength for bright single photon sources

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    Cavity QED is the art of enhancing light-matter interaction of photon emitters in cavities, with opportunities for sensing, quantum information and energy capture technologies. To boost emitter-cavity interaction, i.e. coupling strength , ultrahigh quality cavities have been concocted yielding photon trapping times of µs to ms. However, such high-Q cavities give poor photon output, hindering applications. To preserve high photon output it is advantageous to strive for highly localised electric fields in radiatively lossy cavities. Nanophotonic antennas are ideal candidates combining low-Q factors with deeply localised mode volumes, allowing large , provided the emitter is positioned exactly right inside the nanoscale mode volume. Here, with nanometre resolution, we map and tune the coupling strength between a dipole nanoantenna-cavity and a single molecule, obtaining a coupling rate of max ~ 200 GHz. Together with accelerated single photon output, this provides ideal conditions for fast and pure non-classical single photon emission with brightness exceeding 10E9 photons/sec. Clearly, nanoantennas acting as “bad” cavities offer an optimal regime for strong coupling , to deliver bright on-demand and ultrafast single photon nanosources for quantum technologies.Peer ReviewedPostprint (author's final draft

    Pendientes de los servicios farmacéuticos comunitarios en México que limitan el uso racional de los medicamentos

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    La posición de la Organización Mundial de la Salud (OMS) y Organización Panamericana de la Salud (OPS) es que los países de la región de las Américas implanten un modelo de servicios farmacéuticos que garantice una atención integral en la salud de la población respecto a los medicamentos y define el uso racional de medicamentos cuando “los pacientes reciben la medicación adecuada a sus necesidades clínicas, en las dosis correspondientes a sus requisitos individuales, durante un período de tiempo adecuado y al menor coste posible para ellos y para la comunidad”.En México el uso inadecuado de los medicamentos representa un problema grave de salud que conlleva a una accesibilidad no equitativa, incrementa los costos de tratamientos y obliga al paciente a convivir con problemas relacionados con la medicación; las instituciones de salud han realizado esfuerzos por promover una política farmacéutica nacional en congruencia con las recomendaciones de la OMS, sin embargo  no se ha tenido el impacto en los indicadores de salud. Por otra parte los profesionales farmacéuticos por diversos factores no influyen como líderes en el desarrollo de un servicio integral orientado al beneficio del paciente (instrucciones para su utilización y orientación ante la detección de problemas relacionados con su manejo) y a su vez el modelo de farmacia comunitaria orienta el servicio más hacia un fin comercial que sanitario. La ciudadanía se mueve entre la expectativa y la incertidumbre derivada de la información recibida de los farmacéuticos, los médicos, los medios de comunicación y de los propios laboratorios farmacéuticos

    Mathematical models of bipolar disorder

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    We use limit cycle oscillators to model bipolar II disorder, which is characterized by alternating hypomanic and depressive episodes and afflicts about 1% of the United States adult population. We consider two non-linear oscillator models of a single bipolar patient. In both frameworks, we begin with an untreated individual and examine the mathematical effects and resulting biological consequences of treatment. We also briefly consider the dynamics of interacting bipolar II individuals using weakly-coupled, weakly-damped harmonic oscillators. We discuss how the proposed models can be used as a framework for refined models that incorporate additional biological data. We conclude with a discussion of possible generalizations of our work, as there are several biologically-motivated extensions that can be readily incorporated into the series of models presented here

    Death ideation in cancer patients: contributing factors

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    Advances in cancer research and therapy have improved prognosis and the quality of life of many patients. However, previous epidemiological studies in oncologic patients have shown an increased risk of suicide. Suicidal thoughts, relatively well known in those terminally ill, may be just as important for cancer patients who are survivors or are living with the disease. Nonetheless, there is a relative paucity of data about suicidality in this setting. The authors conducted a prospective observational study to identify death thoughts and to explore the factors associated with suicidal ideation in cancer patients. A sample of 130 patients referred for psychiatric consultation was obtained following informed consent and authorization from the local ethics committee. A semistructured interview assessed sociodemographic data, psychosocial support, and information regarding the cancer process and its treatment. Psychometric instruments were used to evaluate psychopathology, namely the Hospital Anxiety and Depression Scale, the Beck Hopelessness Scale, and the Beck Scale for Suicide Ideation. Psychiatric diagnoses were obtained through the application of the Mini International Neuropsychiatric Interview. Death ideation was identified in 34.6% of patients, yet only 10% had active suicidal thoughts. Risk of suicide was associated with female gender, a psychiatric diagnosis (major depressive disorder, panic disorder, or dysthymia), difficult interpersonal relationships, associated pain, high hopelessness, and depressive and anxiety symptoms. Although suicidal thoughts are frequent in cancer patients at different stages of disease, most are transitory. Risk factors for suicidal ideation have been identified, such as depression, hopelessness, uncontrolled pain, and difficult interpersonal relationships. Further assessment is necessary to identify those at higher risk of attempting suicide, and underlying psychiatric disorders should be vigorously treated

    Glycan microarray analysis of the carbohydrate-recognition specificity of native and recombinant forms of the lectin ArtinM

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    This article contains data related to the researc.h article entitled Yeast-derived ArtinM shares structure, carbohydrate recognition, and biological effects with native ArtinM by Cecílio et al. (2015) [1]. ArtinM, a D-mannose-binding lectin isolated from the seeds of Artocarpus heterophyllus, exerts immunomodulatory and regenerative activities through its Carbohydrate Recognition Domain (CRD) (Souza et al., 2013; Mariano et al., 2014 [2], [3]). The limited availability of the native lectin (n-ArtinM) led us to characterize a recombinant form of the protein, obtained by expression in Saccharomyces cerevisiae (y-ArtinM). We compared the carbohydrate-binding specificities of y-ArtinM and n-ArtinM by analyzing the binding of biotinylated preparations of the two lectin forms using a neoglycolipid (NGL)-based glycan microarray. Data showed that y-ArtinM mirrored the specificity exhibited by n-ArtinM

    Application of Photovoice with Focus Groups to Explore Dietary Behaviors of Older Filipino Adults with Cardiovascular Disease

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    Filipino Americans have high rates of cardiovascular diseases (CVD). This study explored the dietary behaviors, a modifiable risk factor, of Filipinos with CVD. Filipinos with CVD were recruited and trained to do Photovoice. Participants took photos to depict their “food experience,” defined as their daily dietary activities. Participants then shared their photos during focus groups. Focus group transcripts were analyzed using an iterative, grounded theory approach. Among 38 Filipino participants, the mean age was 70 years old and all were foreign-born. Major themes included efforts to retain connection to Filipino culture through food, and dietary habits shaped by cultural health beliefs. Many believed that traditional dietary practices increased CVD risk. Receiving a CVD diagnosis and clinician advice changed their dietary behaviors. Household members, the physical environment, and economic constraints also influenced dietary behaviors. Photovoice is feasible among older Filipinos and may enhance understanding of drivers of dietary behaviors

    Chromatic Adaptation in an Immersive Viewing Environment

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    A hollow fibreglass sphere of 750 mm diameter was used to create an immersive mesopic viewing environment. Light was projected through a series of 20nm-bandwidth filters to illuminate the interior of the sphere with a near-monochromatic adapting field. The task of the observer was to set a target to appear neutral grey, using two interactive slider controls. The results suggest that chromatic adaptation is continuing even after an hour, suggesting the influence of retinal mechanisms with a very long time period
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