Noise-free high-efficiency photon-number-resolving detectors

High-efficiency optical detectors that can determine the number of photons in a pulse of monochromatic light have applications in a variety of physics studies, including post-selection-based entanglement protocols for linear optics quantum computing and experiments that simultaneously close the detection and communication loopholes of Bell's inequalities. Here we report on our demonstration of fiber-coupled, noise-free, photon-number-resolving transition-edge sensors with 88% efficiency at 1550 nm. The efficiency of these sensors could be made even higher at any wavelength in the visible and near-infrared spectrum without resulting in a higher dark-count rate or degraded photon-number resolution.Comment: 4 pages, 4 figures Published in Physical Review A, Rapid Communications, 17 June 200

Experimental study of clast orientation in gravels deposited by unidirectional flow

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1985.Microfiche copy available in Archives and Science.Bibliography: leaves 83-84.by James G. Danna.M.S

Selecting and Training Contact Tracers to Address Minority Health Disparities: Lessons from COVID-19

Like most public health emergencies, COVID-19 has disproportionately impacted minority communities and exacerbated pre-existing health disparities (Hooper et al., 2020; Selden & Berdahl, 2020). Contact tracing, which refers to the process of contacting individuals who have been exposed to a communicable disease, collecting information about who they have been in close proximity with, and making suitable recommendations for testing, quarantine, and medical care, is one particularly effective method for reducing the spread of disease. Consequently, state and local governments had to rapidly hire, train, and send forth an “army” of contact tracers to help mitigate the spread of COVID-19 in order to safely reopen schools and the economy. However, not much was known about the individual characteristics required to perform this critical job effectively, particularly in a way that ensured equal treatment of all individuals and effective contact with minority communities. Randall et al. (2021) and Dalal et al. (2021) showed that well selected and trained contact tracers, and trust and knowledge about the contact tracing role are critical aspects of contact tracing compliance among minority individuals during the COVID-19 pandemic. From these two research studies, we identify that a gap in addressing minority health disparities has been a lack of considering the science of personnel psychology in developing a well-skilled and well-trained workforce to work in minority communities; communities in which trust in healthcare and government institutions has been eroded due to historical, systemic mistreatment of minority groups. Drawing on theories from personnel psychology (e.g., Guion, 2011), we present a blueprint to extend this work by presenting a comprehensive picture of procedures to efficiently, fairly, and validly select and train contact tracers to address future public health crises, and to effectively work within minority communities. Future steps to develop selection and training systems are also identified to facilitate the establishment of a contact tracing personnel system and to expand these procedures to other public-facing health support positions. Being more proactive in preparing public health personnel to work more effectively in minority communities should increase preparation for future health crises and contribute to the elimination of minority health disparities. The information shared in this project will guide this future work by presenting the steps needed to achieve this goal

Identifying Critical Psychological Characteristics Related to Successful Performance as a Contact Tracer: A Job Analysis

The COVID-19 pandemic highlighted the need for a massive workforce of contact tracers to help end the global pandemic. Rapidly accelerating the recruitment, selection, and training of contact tracers proved to be difficult due in part to the lack of a valid, structured, and systematic approach to hiring and training contact tracers. This demonstration presents the results of the first step in developing a systematic selection and training program: a worker-oriented job analysis of the contact tracer job. Using archival records and structured interviews with 15 subject matter experts, we identified 26 unique characteristics related to successful performance as a contact tracer. We also identify which are needed as part of selection versus those that can be trained, and develop predictive hypotheses for each. Results jump-start the process of developing a systematic approach to selecting and training contact tracers to help end the COVID-19 pandemic and navigate future public health emergencies

Eco-evolutionary dynamics of experimental Pseudomonas aeruginosa populations under oxidative stress

Within-host environments are likely to present a challenging and stressful environment for opportunistic pathogenic bacteria colonizing from the external environment. How populations of pathogenic bacteria respond to such environmental challenges and how this varies between strains is not well understood. Oxidative stress is one of the defences adopted by the human immune system to confront invading bacteria. In this study, we show that strains of the opportunistic pathogenic bacterium Pseudomonas aeruginosa vary in their eco-evolutionary responses to hydrogen peroxide stress. By quantifying their 24 h growth kinetics across hydrogen peroxide gradients we show that a transmissible epidemic strain isolated from a chronic airway infection of a cystic fibrosis patient, LESB58, is much more susceptible to hydrogen peroxide than either of the reference strains, PA14 or PAO1, with PAO1 showing the lowest susceptibility. Using a 12 day serial passaging experiment combined with a mathematical model, we then show that short-term susceptibility controls the longer-term survival of populations exposed to subinhibitory levels of hydrogen peroxide, but that phenotypic evolutionary responses can delay population extinction. Our model further suggests that hydrogen peroxide driven extinctions are more likely with higher rates of population turnover. Together, these findings suggest that hydrogen peroxide is likely to be an effective defence in host niches where there is high population turnover, which may explain the counter-intuitively high susceptibility of a strain isolated from chronic lung infection, where such ecological dynamics may be slower

The role of China in the redefinition of destinations: case of Argentina

En la última década el crecimiento de China como mercado emisor de turismo ha sido y sigue siendo el más rápido del mundo, tanto en arribos internacionales como en gasto. El incremento del poder adquisitivo de sus ciudadanos los transforma en un mercado clave y fundamental para el desarrollo y crecimiento de los destinos emergentes como Argentina. Sin embargo, a diferencia de los mercados tradicionales, China presenta el desafío de generar políticas turísticas que tengan como objetivo la diplomacia entre ambos países, y la adaptación de la oferta turística a las exigencias de un perfil de turista oriental, digital y de alta gama. En este ensayo nos preguntamos entonces, qué tan lejos estamos como país de alcanzar al gigante asiático. ¿Será una utopía o en desafío en el cual trabajar?.China, which has led growth as a tourism market over the last decade, has been and continues to be the fastest tourism economy in the world, both in international arrivals and in spending. The increase in the purchasing power of its citizens makes them a key and fundamental market for the development and growth of emerging destinations such as Argentina. In contrast to traditional markets, however, China presents the challenge of generating tourism policies aimed at diplomacy between the two countries, and adapting the tourist offer to the requirements of an oriental, digital and high-end tourist profile. In this research, we ask ourselves how far we are as a country to reach the Asian giant. Will it be a utopia or a challenge in which to work?.Facultad de Ciencias Económica

El rol de china en la redefinición de los destinos turísticos caso argentina /

En la última década el crecimiento de China como mercado emisor de turismo ha sido y sigue siendo el más rápido del mundo, tanto en arribos internacionales como en gasto. El incremento del poder adquisitivo de sus ciudadanos los transforma en un mercado clave y fundamental para el desarrollo y crecimiento de los destinos emergentes como Argentina.Sin embargo, a diferencia de los mercados tradicionales, China presenta el desafío de generar políticas turísticas que tengan como objetivo la diplomacia entre ambos países, y la adaptación de la oferta turística a las exigencias de un perfil de turista oriental, digital y de alta gama.En este ensayo nos preguntamos entonces, qué tan lejos estamos como país de alcanzar al gigante asiático. ¿Será una utopía o en desafío en el cual trabajar