23 research outputs found
Mechanical Attributes of Fractal Dragons
Fractals are ubiquitous natural emergences that have gained increased
attention in engineering applications, thanks to recent technological
advancements enabling the fabrication of structures spanning across many
spatial scales. We show how the geometries of fractals can be exploited to
determine their important mechanical properties, such as the first and second
moments, which physically correspond to the center of mass and the moment of
inertia, using a family of complex fractals known as the dragons
VLTI status update: a decade of operations and beyond
We present the latest update of the European Southern Observatory's Very
Large Telescope interferometer (VLTI). The operations of VLTI have greatly
improved in the past years: reduction of the execution time; better offering of
telescopes configurations; improvements on AMBER limiting magnitudes; study of
polarization effects and control for single mode fibres; fringe tracking real
time data, etc. We present some of these improvements and also quantify the
operational improvements using a performance metric. We take the opportunity of
the first decade of operations to reflect on the VLTI community which is
analyzed quantitatively and qualitatively. Finally, we present briefly the
preparatory work for the arrival of the second generation instruments GRAVITY
and MATISSE.Comment: 10 pages, 7 figures, Proceedings of the SPIE, 9146-1
Growing up -the completion of the VLTI
Abstract. The completed VLTI with eight Delay Lines and eight ATs forms the basis for the second generation instrumentation. We describe the events up to first fringes with the test instrument VINCI using the siderostats, and the planning for the immediate future. Multi beam combination for 'smoother images' will be briefly discussed as well as artificial guide stars for fringe tracking. New technological developments like fiber optics amplifiers and integrated optics in combination with STJ open the door for a new type of interferometric arrays. Baselines as long as a a few kilometres come into reach. Examples of these second generation interferometers will be given
Socializing One Health: an innovative strategy to investigate social and behavioral risks of emerging viral threats
In an effort to strengthen global capacity to prevent, detect, and control infectious diseases in animals and people, the United States Agency for International Development’s (USAID) Emerging Pandemic Threats (EPT) PREDICT project funded development of regional, national, and local One Health capacities for early disease detection, rapid response, disease control, and risk reduction. From the outset, the EPT approach was inclusive of social science research methods designed to understand the contexts and behaviors of communities living and working at human-animal-environment interfaces considered high-risk for virus emergence. Using qualitative and quantitative approaches, PREDICT behavioral research aimed to identify and assess a range of socio-cultural behaviors that could be influential in zoonotic disease emergence, amplification, and transmission. This broad approach to behavioral risk characterization enabled us to identify and characterize human activities that could be linked to the transmission dynamics of new and emerging viruses. This paper provides a discussion of implementation of a social science approach within a zoonotic surveillance framework. We conducted in-depth ethnographic interviews and focus groups to better understand the individual- and community-level knowledge, attitudes, and practices that potentially put participants at risk for zoonotic disease transmission from the animals they live and work with, across 6 interface domains. When we asked highly-exposed individuals (ie. bushmeat hunters, wildlife or guano farmers) about the risk they perceived in their occupational activities, most did not perceive it to be risky, whether because it was normalized by years (or generations) of doing such an activity, or due to lack of information about potential risks. Integrating the social sciences allows investigations of the specific human activities that are hypothesized to drive disease emergence, amplification, and transmission, in order to better substantiate behavioral disease drivers, along with the social dimensions of infection and transmission dynamics. Understanding these dynamics is critical to achieving health security--the protection from threats to health-- which requires investments in both collective and individual health security. Involving behavioral sciences into zoonotic disease surveillance allowed us to push toward fuller community integration and engagement and toward dialogue and implementation of recommendations for disease prevention and improved health security
The influence of Tantalum content in relation to substrate temperature on magnetic and structural properties of Co-Cr-Ta thin films
In this study, we investigated the influence of Ta content (in Co86Cr12Ta2 and Co82Cr13Ta5 compositions) on magnetic and structural properties of Co–Cr–Ta perpendicular media samples grown on Si substrates at different substrate temperatures during RF-sputter deposition. In general, coercivity of Co82Cr13Ta5 samples is higher than that of Co86Cr12Ta2 samples, whereas the perpendicular c-axis orientation of Co86Cr12Ta2 samples is better. Ta content was suggested to be in between 2 and 5 at% to give optimum magnetic and structural properties
The VINCI instrument software in the very large telescope environment
International audienc
VINCI, the VLTI commissioning instrument: status after one year of operations at Paranal
International audienc
VINCI, the VLTI commissioning instrument: status after one year of operations at Paranal
International audienc