Coupling Rydberg atoms to superconducting microwave circuits

A hybrid circuit quantum electro-dynamics (circuit QED) setup consisting of helium atoms in high-n Rydberg states and superconducting co-planar waveguide (CPW) microwave resonators has been developed with the goal of performing hybrid quantum optics experiments with applications in quantum information processing. In this thesis an overview of the field of cavity QED is introduced, and numerical methods to calculate the atomic energy level structure and transition dipole moments in electric and magnetic fields are described. Using this background information, a new method for efficiently preparing high-n circular Rydberg states is presented. This was required to ac- cess circular-state–to–circular-state transition frequencies in experiments which are compatible with superconducting CPW microwave resonators. Experimental and numerical results demonstrating the implementation of this method for the preparation of the |n = 70, l = 69, ml = +69⟩ circular state in helium are reported. The design and fabrication of λ/4 superconducting CPW microwave resonators, compatible with these high-n circular Rydberg states of helium is then described. The effects of microwave driving power, temperature and magnetic field on the characteristics of these resonators are presented. Finally, experiments in which helium Rydberg atoms have been coherently coupled to the microwave field of a superconducting co-planar waveguide resonator are reported

Toward a Theoretical View of Dance Leadership

This is a theoretical dissertation, creating a beginning understanding of dance leadership.The subject is absent from both the dance and the leadership literature; therefore the concepts have been developed from the experiences of practice and integrated with concepts from those of outside disciplines through the process of reflective synthesis.In order to create this beginning understanding, dance leadership is established herein in its own domain, separate from both dance and leadership.It is a form of informal leadership—that is, not conferred by title or position within an organization—specifically leading in place, practiced by individual or groups of dancers with the goal of furthering dance.It occurs in the space of dance leadership, different from the artist/s work in dance; and involves stepping forward into a space which recognizes an obligation to dance.As leadership in place, it carries no expectation of a permanent change in role; it is not tied to a title or an organization.Dance has been established herein as an intrinsic human activity; therefore dance leadership activities may be expected to ease/further the human condition, but the direction of the activity is toward furthering dance.Dancers function as leaders by virtue of the knowledge and skills they hold as dancers; their leadership is tied inextricably to their practice and is rooted in the fact of their being artists.Dance leadership is practiced at least in the forms of dancing, speaking, and writing; there may be other forms as well.The establishment of the domain of dance leadership proposes a number of emergent issues to be addressed by dance leaders, as well as issues of concern for dance, leadership, and other academic disciplines.The electronic version of this dissertation is at OhioLink ETD Center, www.ohiolink.edu/etd.This pdf is accompanied by two mp4 files

Toward a Theoretical View of Dance Leadership

This is a theoretical dissertation, creating a beginning understanding of dance leadership.The subject is absent from both the dance and the leadership literature; therefore the concepts have been developed from the experiences of practice and integrated with concepts from those of outside disciplines through the process of reflective synthesis.In order to create this beginning understanding, dance leadership is established herein in its own domain, separate from both dance and leadership.It is a form of informal leadership—that is, not conferred by title or position within an organization—specifically leading in place, practiced by individual or groups of dancers with the goal of furthering dance.It occurs in the space of dance leadership, different from the artist/s work in dance; and involves stepping forward into a space which recognizes an obligation to dance.As leadership in place, it carries no expectation of a permanent change in role; it is not tied to a title or an organization.Dance has been established herein as an intrinsic human activity; therefore dance leadership activities may be expected to ease/further the human condition, but the direction of the activity is toward furthering dance.Dancers function as leaders by virtue of the knowledge and skills they hold as dancers; their leadership is tied inextricably to their practice and is rooted in the fact of their being artists.Dance leadership is practiced at least in the forms of dancing, speaking, and writing; there may be other forms as well.The establishment of the domain of dance leadership proposes a number of emergent issues to be addressed by dance leaders, as well as issues of concern for dance, leadership, and other academic disciplines.The electronic version of this dissertation is at OhioLink ETD Center, www.ohiolink.edu/etd.This pdf is accompanied by two mp4 files

Considering the role of the teacher: Buber, Freire and Gur-Ze’ev

This article considers three different concepts of the role of the teacher. Buber understands the teacher as the builder-teacher of a dialogical community playing a fundamental role in the character formation of individuals. Freire develops this notion, adding a political tinge, and argues for a political-teacher who plays a central role in the formation of critical individuals and in the liberation of the oppressed. Gur-Ze’ev is critical of Freire and defends the improviser-teacher, who is always critical and encourages criticisms, but without reference to utopias. The article compares and assesses critically these concepts of the role of the teacher; and indicates the implications of adopting them, not only for education, but also for society more generally

Energy-based modelling to assess effects of chemicals on Caenorhabditis elegans: A case study on uranium

International audienceThe ubiquitous free-living nematode Caenorhabditis elegans is a powerful animal model for measuring the evolutionary effects of pollutants which is increasingly used in (eco)toxicological studies. Indeed, toxicity tests with this nematode can provide in a few days data on the whole life cycle. These data can be analysed with mathematical tools such as toxicokinetic-toxicodynamic modelling approaches. In this study, we assessed how a chronic exposure to a radioactive heavy metal (uranium) affects the life-cycle of C. elegans using a mechanistic model. In order to achieve this, we exposed individuals to a range of seven concentrations of uranium. Growth and reproduction were followed daily. These data were analysed with a model for nematodes based on the Dynamic Energy Budget theory, able to handle a wide range of plausible biological parameters values. Parameter estimations were performed using a Bayesian framework. Our results showed that uranium affects the assimilation of energy from food with a no-effect concentration (NEC) of 0.42 mM U which would be the threshold for effects on both growth and reproduction. The sensitivity analysis showed that the main contributors to the model output were parameters linked to the feeding processes and the actual exposure concentration. This confirms that the real exposure concentration should be measured accu-rately and that the feeding parameters should not be fixed, but need to be reestimated during the parameter estimation process

Optophysiological characterisation of inner retina responses with high-resolution optical coherence tomography

Low coherence laser interferometry has revolutionised quantitative biomedical imaging of optically transparent structures at cellular resolutions. We report the first optical recording of neuronal excitation at cellular resolution in the inner retina by quantifying optically recorded stimulus-evoked responses from the retinal ganglion cell layer and comparing them with an electrophysiological standard. We imaged anaesthetised paralysed tree shrews, gated image acquisition, and used numerical filters to eliminate noise arising from retinal movements during respiratory and cardiac cycles. We observed increases in contrast variability in the retinal ganglion cell layer and nerve fibre layer with flash stimuli and gratings. Regions of interest were subdivided into three-dimensional patches (up to 5-15μm in diameter) based on response similarity. We hypothesise that these patches correspond to individual cells, or segments of blood vessels within the inner retina. We observed a close correlation between the patch optical responses and mean electrical activity of afferent visual neurons. While our data suggest that optical imaging of retinal activity is possible with high resolution OCT, the technical challenges are not trivial

A review of capture-recapture methods and its possibilities in ophthalmology and vision sciences

Epidemiological information is expected to be used to develop key aspects of eye care such as to control and minimise the impact of diseases, to allocate resources, to monitor public health actions, to determine the best treatment options and to forecast the consequence of diseases in populations. Epidemiological studies are expected to provide information about the prevalence and/or incidence of eye diseases or conditions. To determine prevalence is necessary to perform a cross-sectional screening of the population at risk to ascertain the number of cases.The aim of this review is to describe and evaluate capture-recapture methods (or models) to ascertaining the number of individuals with a disease (e.g. diabetic retinopathy) or condition (e.g. vision impairment) in the population.The review covers the fundamental aspects of capture-recapture methods that would enable non-experts in epidemiology to use it in ophthalmic studies. The review provides information about theoretical aspects of the method with examples of studies in ophthalmology in which it has been used. We also provide a problem/solution approach for limitations arising from the lists obtained from registers or other reliable sources.We concluded that capture-recapture models can be considered reliable to estimate the total number of cases with eye conditions using incomplete information from registers. Accordingly, the method may be used to maintain updated epidemiological information about eye conditions helping to tackle the lack of surveillance information in many regions of the globe.- This study was supported by FCT (COMPETE/QREN) grant reference [PTDC/DPT-EPI/0412/2012] in the context of the Prevalence and Costs of Visual Impairment in Portugal: a hospital-based study (PCVIP-study) and FCT Strategic Funding UID/FIS/04650/2013. PLR is funded by FCT (COMPETE/QREN) grant reference [SFRH/BD/119420/2016]

Système de récupération d'énergie thermique à base de matériaux magnétocaloriques

International audience-Les générateurs thermomagnétiques convertissent le flux de chaleur en énergie électrique. Le matériau magnétocalorique (MMC) réalise un cycle thermodynamique entre deux sources de chaleur ce qui produit une variation d'aimantation du matériau. Cette énergie (variation d'aimantation) est ensuite transformée en énergie mécanique via les forces magnétiques et enfin en énergie électrique via un transducteur électromécanique. Le dimensionnement du cantilever permettant l'auto-oscillation du MMC entre les deux sources de chaleur nous a permis de déduire la vitesse au cours des déplacements. Ainsi à partir du modèle où le transducteur est découplé de la partie mécanique, nous avons à l'aide de simulation par éléments finis estimé l'aptitude d'un transducteur piézoélectriques (PZT 5a) et de bobines à convertir l'énergie mécanique en énergie électrique. Le système à base de piézoélectriques et de bobines récupèrent seulement 0,025 % et 0,018% respectivement de l'énergie mécanique disponible (116 mJ/cm 3). Finalement quelques pistes seront soulevées pour expliquer les faibles valeurs obtenues et les stratégies possibles pour y remédier Mots-clés-Matériaux Magnétocalorique, Thermomagnétique, Récupération d'énergie thermique, Energie