Interactions between a colour centre, optical and mechanical resonator modes in a diamond structure

This work shows a route towards the implementation of diamond-based platforms as highly integrated system for quantum information processing. To this end, a structure where three degrees of freedom mutually couple at the single particle level is investigated based on numerical modelling. A practical implementation is tested and challenges towards an experimental demonstration are identified. The structure considered in this work is a photonic and phononic crystal that confines an optical and a mechanical resonator mode and that hosts a colour centre. Besides the well-explored Purcell coupling, optomechanical interaction and strain coupling to both the ground and excited state levels of a single nitrogen vacancy colour centre determine the dynamics in this structure. In addition, a hybrid interaction involving all three degrees of freedom is explored to demonstrate the unique possibilities in this highly integrated system. With regard to an experimental implementation, established fabrication techniques are improved and a novel dry etching technique is developed with the aim to achieve a better mode confinement. The practical feasibility of measurements in vacuum, required for detecting the mechanical oscillation via optomechanical or strain coupling, is assessed. Unexpected features in the optical mode spectrum are detected and systematically investigated so that a future experimental demonstration is within reach.In dieser Arbeit wird eine Diamantplattform als hochintegriertes System im Bereich der Quanteninformationsverarbeitung vorgestellt. Dazu wird eine Struktur simuliert, in der drei Freiheitsgrade auf der Ebene einzelner Quanten in Wechselwirkung treten. Eine praktische Umsetzung wird getestet wobei Hindernisse auf dem Weg zu einer experimentellen Demonstration identifiziert werden. In dieser Arbeit wird ein photonischer und phononischer Kristall untersucht, der eine optische und eine mechanische Resonatormode lokalisiert und in dessen Mitte ein Farbzentrum eingebracht ist. Neben der bekannten Purcell-Kopplung bestimmen optomechanische Kopplung und die Wechselwirkung zwischen mechanischer Schwingung und den Grund- und angeregten Zuständen eines einzelnen Stickstoff-Fehlstellen-Zentrums die Dynamik des Systems. Darüber hinaus wird eine gleichzeitige Wechselwirkung aller drei Freiheitsgrade untersucht um die einzigartigen Möglichkeiten dieses hochintegrierten Systems aufzuzeigen. Im Hinblick auf eine experimentelle Umsetzung werden bekannte Herstellungstechniken verbessert und ein neues Trockenätzverfahren entwickelt um eine bessere Lokalisation der Moden zu erzielen. Messungen im Vakuum, die für den indirekten Nachweis der mechanischen Schwingung über optomechanische Kopplung nötig sind, werden getestet. Dabei wird ein unerwartetes Verhalten der optischen Eigenschaften beobachtet und systematisch untersucht sodass eine experimentelle Umsetzung in greifbare Nähe rückt

Directional emission of white light via selective amplification of photon recycling and Bayesian optimization of multi-layer thin films

Over the last decades, light-emitting diodes (LED) have replaced common light bulbs in almost every application, from flashlights in smartphones to automotive headlights. Illuminating nightly streets requires LEDs to emit a light spectrum that is perceived as pure white by the human eye. The power associated with such a white light spectrum is not only distributed over the contributing wavelengths but also over the angles of vision. For many applications, the usable light rays are required to exit the LED in forward direction, namely under small angles to the perpendicular. In this work, we demonstrate that a specifically designed multi-layer thin film on top of a white LED increases the power of pure white light emitted in forward direction. Therefore, the deduced multi-objective optimization problem is reformulated via a real-valued physics-guided objective function that represents the hierarchical structure of our engineering problem. Variants of Bayesian optimization are employed to maximize this non-deterministic objective function based on ray tracing simulations. Eventually, the investigation of optical properties of suitable multi-layer thin films allowed to identify the mechanism behind the increased directionality of white light: angle and wavelength selective filtering causes the multi-layer thin film to play ping pong with rays of light

Estado dental y periodontal de población en tratamiento por consumo de drogas. Estudio piloto

Artículo originalEl uso problemático de drogas puede afectar la salud oral de los consumidores. El presente estudio pretendió detectar la prevalencia de patología dentaria y periodontal en una población adolescente y adulta joven en tratamiento por drogo-dependencia. Se diseñó un estudio transversal, observacional y descriptivo, incluyendo a 72 individuos que se asisten por su adicción en el Portal Amarillo, centro de referencia nacional. La media del índice CPOD fue de 8,04. Al discriminar por franja etaria, la comprendida entre 15 y 24 años tuvo un CPOD de 5,31, mientras que la comprendida entre 25 y 35 años tuvo un valor de 11,27. El relevamiento paradencial mostró que el 65% de los participantes presentaron gingivitis y el 18% cuadros de periodontitis. Los resultados obtenidos mostraron que existe una mayor prevalencia de enfermedad oral en pacientes drogo-dependientes que la población general. Los servicios de salud del primer nivel deberían desarrollar acciones especiales de prevención y detección precoz en pacientes drogo-dependiente

MEDINFO 2021: One World, One Health – Global Partnership for Digital Innovation

We evaluate the performance of multiple text classification methods used to automate the screening of article abstracts in terms of their relevance to a topic of interest. The aim is to develop a system that can be first trained on a set of manually screened article abstracts before using it to identify additional articles on the same topic. Here the focus is on articles related to the topic "artificial intelligence in nursing". Eight text classification methods are tested, as well as two simple ensemble systems. The results indicate that it is feasible to use text classification technology to support the manual screening process of article abstracts when conducting a literature review. The best results are achieved by an ensemble system, which achieves a F1-score of 0.41, with a sensitivity of 0.54 and a specificity of 0.96. Future work directions are discussed

Study protocol: EXERcise and Cognition In Sedentary adults with Early-ONset dementia (EXERCISE-ON)

<p>Abstract</p> <p>Background</p> <p>Although the development of early-onset dementia is a radical and invalidating experience for both patient and family there are hardly any non-pharmacological studies that focus on this group of patients. One type of a non-pharmacological intervention that appears to have a beneficial effect on cognition in older persons without dementia and older persons at risk for dementia is exercise. In view of their younger age early-onset dementia patients may be well able to participate in an exercise program. The main aim of the EXERCISE-ON study is to assess whether exercise slows down the progressive course of the symptoms of dementia.</p> <p>Methods/Design</p> <p>One hundred and fifty patients with early-onset dementia are recruited. After completion of the baseline measurements, participants living within a 50 kilometre radius to one of the rehabilitation centres are randomly assigned to either an <it>aerobic exercise program in a rehabilitation centre</it> or a <it>flexibility and relaxation program in a rehabilitation centre</it>. Both programs are applied three times a week during 3 months. Participants living outside the 50 kilometre radius are included in a feasibility study where participants join in a <it>daily physical activity program set at home making use of pedometers</it>. Measurements take place at baseline (entry of the study), after three months (end of the exercise program) and after six months (follow-up). Primary outcomes are cognitive functioning; psychomotor speed and executive functioning; (instrumental) activities of daily living, and quality of life. Secondary outcomes include physical, neuropsychological, and rest-activity rhythm measures.</p> <p>Discussion</p> <p>The EXERCISE-ON study is the first study to offer exercise programs to patients with early-onset dementia. We expect this study to supply evidence regarding the effects of exercise on the symptoms of early-onset dementia, influencing quality of life.</p> <p>Trial registration</p> <p>The present study is registered within The Netherlands National Trial Register (ref: NTR2124)</p