Strong Electron-Hole Exchange in Coherently Coupled Quantum Dots

We have investigated few-body states in vertically stacked quantum dots. Due to small inter-dot tunneling rate, the coupling in our system is in a previously unexplored regime where electron-hole exchange is the dominant spin interaction. By tuning the gate bias, we are able to turn this coupling off and study a complementary regime where total electron spin is a good quantum number. The use of differential transmission allows us to obtain unambiguous signatures of the interplay between electron and hole spin interactions. Small tunnel coupling also enables us to demonstrate all-optical charge sensing, where conditional exciton energy shift in one dot identifies the charging state of the coupled partner.Comment: 10 pages, 3 figure

The positive impacts (potential benefits)

UIDB/04647/2020 UIDP/04647/2020This paper intended to provide a vision on the potential consequences of the introduction of emerging air transportation system which was based on a section of the thesis to contribute to the forming of public and policy opinion.Especially this paper tried to understand whether there were enough positive social and environmental impacts in terms of potential benefits to continue the efforts.The negative impacts are beyond the scope of this paper. Limitations of the current ground and airline transportation systems, increasing congestion, poor block speed, combined with expanding population and demand for affordable on-demand mobility are driving the development of future transportation technology and policy. The third wave of aeronautic,e VTOL (Vertical Takeoff and landing) Air Transportation System, is envisioned as the next logical step in the natural progression and could bring about great new capabilities for society that would bring aviation into a new age of being relevant in daily lives. Considering door to door block time, e VTOL Air Transportation System has the potential to achieve anotherfive-fold increase over the auto today as the auto provided ten-fold increase over the horse, and a daily mobility reach of 125 to 250 miles.The main benefits will be on-demand, point-to-point,safe travel, further and anywhere in less travel time with almost zero environmental impact for general people. Besides, a successful implementation and sustainable transition will depend on overcoming technological hurdles, regulatory frameworks, operational safety, cost competitiveness, and sensibilities of the affected communities.publishersversionpublishe

Supporting Metacognitive Awareness and Strategy Use Through Digital Photography in a Rural Title I School

The Photography and Media Literacy Project (PMLP) was an after-school program designed to teach fourth and fifth grade children about the science and art of photography in a Title I school in rural southeast Georgia. Through the completion of a problem-based applied project, we endeavored to further enhance and develop students’ media literacy, critical thinking, and metacognitive skills. The project involved having students consider some aspect of their environment (i.e., a problem from the natural, physical, school or social environment) and develop a media presentation about the topic (e.g., a movie), which included images that they took (with iPods that we provided), as well as a narrative that described their observation, research, argument and/or experience. Through the use of technology and various other media, our purpose was to help these young learners improve their metacognitive planning and monitoring skills, as well as their problem-solving and reasoning ability, all foundational skills critical for success in high stakes assessments such as Georgia Milestone Assessment. Although no significant differences were found in pre-posttest assessments, we believe that with minor modifications, this type of program shows promise in its potential for boosting participants’ metacognitive functioning and other skills related to critical evaluation of information, which have been found to enhance learning outcomes

new insights into the development and progression of geographic atrophy after full thickness autologous choroidal graft

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Seguidor lumínico con dos grados de libertad

Un seguidor lumínico es un dispositivo mecánico capaz seguir un haz de luz Existe una gran variedad de seguidores de luz en el mercado. La clasificación de éstos se puede hacer atendiendo a varios factores tales como el tipo de plataforma, el número de ejes o el tipo de unidad de control.El objetivo de este proyecto, es construir y programar un seguidor lumínico con dos grados de libertad, que sea capaz seguir un haz de luz.Departamento de Ingeniería de Sistemas y AutomáticaIngeniero Técnico Industrial, Especialidad en Electrónica Industria

Observation of Faraday rotation from a single confined spin

Ability to read-out the state of a single confined spin lies at the heart of solid-state quantum information processing. While all-optical spin measurements using Faraday rotation has been successfully implemented in ensembles of semiconductor spins, read-out of a single semiconductor spin has only been achieved using transport measurements based on spin-charge conversion. Here, we demonstrate an all-optical dispersive measurement of the spin-state of a single electron trapped in a semiconductor quantum dot. We obtain information on the spin state through conditional Faraday rotation of a spectrally detuned optical field, induced by the polarization- and spin-selective trion (charged quantum dot) transitions. To assess the sensitivity of the technique, we use an independent resonant laser for spin-state preparation. An all-optical dispersive measurement on single spins has the important advantage of channeling the measurement back-action onto a conjugate observable, thereby allowing for repetitive or continuous quantum nondemolition (QND) read-out of the spin-state. We infer from our results that there are of order unity back-action induced spin-flip Raman scattering events within our measurement timescale. Therefore, straightforward improvements such as the use of a solid-immersion lens and higher efficiency detectors would allow for back-action evading spin measurements, without the need for a cavity

Network protocol scalability via a topological Kadanoff transformation

A natural hierarchical framework for network topology abstraction is presented based on an analogy with the Kadanoff transformation and renormalisation group in theoretical physics. Some properties of the renormalisation group bear similarities to the scalability properties of network routing protocols (interactions). Central to our abstraction are two intimately connected and complementary path diversity units: simple cycles, and cycle adjacencies. A recursive network abstraction procedure is presented, together with an associated generic recursive routing protocol family that offers many desirable features.Comment: 4 pages, 5 figures, PhysComNet 2008 workshop submissio

The relative rate of kill of the MMV Malaria Box compounds provide links to the mode of antimalarial action and highlight scaffolds of medicinal chemistry interest

Objectives: Rapid rate-of-kill (RoK) is a key parameter in the target candidate profile 1 (TCP1) for the next-generation antimalarial drugs for uncomplicated malaria, termed Single Encounter Radical Cure and Prophylaxis (SERCaP). TCP1 aims to rapidly eliminate the initial parasite burden, ideally as fast as artesunate, but minimally as fast as chloroquine. Here we explore whether the relative RoK of the Medicine for Malaria Venture (MMV) Malaria Box compounds are linked to their mode of action (MoA) and identify scaffolds of medicinal chemistry interest. Methods: We used a Bioluminescence Relative RoK (BRRoK) assay over 6 and 48h, with exposure to equipotent-IC50 concentrations, to compare the cytocidal effects of Malaria Box compounds to benchmark antimalarials. Results: BRRoK assay data demonstrate the following relative RoK from fast to slow: inhibitors of 31 PfATP4 > parasite hemoglobin catabolism > DHFR-TS > DHODH > bc1 complex. Core scaffold clustering analyses reveal intrinsic rapid cytocidal action for diamino-glycerols and 2- (aminomethyl)phenol, but slow action for 2-phenylbenzimidazoles, 8-hydroxyquinolines, and triazolopyrimidines. Conclusions: This study provides proof of principle that a compound’s RoK is related to its MoA and that the target’s intrinsic RoK is also modified by factors affecting a drug’s access to it. Our findings highlight that as we use medicinal chemistry to improve potency, we can also improve the RoK for some scaffolds. Our BRRoK assay provides the necessary throughput for drug discovery and a critical decision-making tool to support development campaigns. Finally, two scaffolds, diamino-glycerols and 2-phenylbenzimidazoles, exhibit fast cytocidal action, inviting medicinal chemistry improvements towards TCP1 candidates