265 research outputs found
The EXoplanetary Circumstellar Environments and Disk Explorer (EXCEDE)
We present an overview of the EXoplanetary Circumstellar Environments and
Disk Explorer (EXCEDE), selected by NASA for technology development and
maturation. EXCEDE will study the formation, evolution and architectures of
exoplanetary systems, and characterize circumstellar environments into stellar
habitable zones. EXCEDE provides contrast-limited scattered-light detection
sensitivities ~ 1000x greater than HST or JWST coronagraphs at a much smaller
effective inner working angle (IWA), thus enabling the exploration and
characterization of exoplanetary circumstellar disks in currently inaccessible
domains. EXCEDE will utilize a laboratory demonstrated high-performance Phase
Induced Amplitude Apodized Coronagraph (PIAA-C) integrated with a 70 cm
diameter unobscured aperture visible light telescope. The EXCEDE PIAA-C will
deliver star-to-disk augmented image contrasts of < 10E-8 and a 1.2 L/D IWA or
140 mas with a wavefront control system utilizing a 2000-element MEMS DM and
fast steering mirror. EXCEDE will provide 120 mas spatial resolution at 0.4
microns with dust detection sensitivity to levels of a few tens of zodis with
two-band imaging polarimetry. EXCEDE is a science-driven technology pathfinder
that will advance our understanding of the formation and evolution of
exoplanetary systems, placing our solar system in broader astrophysical
context, and will demonstrate the high contrast technologies required for
larger-scale follow-on and multi-wavelength investigations on the road to
finding and characterizing exo-Earths in the years ahead
Wage Inequality and Offshoring: Are They Related?
The objective of this paper is to investigate the impact of offs ho ring on wage inequality and labor productivity in the U.S. Short-run and long-run data tests are undertaken to analyze the relationship among off shoring, wage inequality, and labor productivity in the U.S. Cointegration tests indicate that these three variables are related in the long-run. The main contribution of this paper lies in its focus on the short-run investigation of the relationship among these three variables. This investigation is conducted using the vector error correction (VEC) testing framework. VEC tests indicate that offshoring has had a statistically significant impact on both labor productivity and wage inequality in the U.S
Crowdsourcing indicators for cultural ecosystem services : a geographically weighted approach for mountain landscapes
This study was partially supported by the OpenNESS project funded from the European Union's Seventh Programme for research; technological development and demonstration under grant agreement n° 308428.Integrating cultural dimensions into the ecosystem service framework is essential for appraising non-material benefits stemming from different human-environment interactions. This study investigates how the actual provision of cultural services is distributed across the landscape according to spatially varying relationships. The final aim was to analyse how landscape settings are associated to people’s preferences and perceptions related to cultural ecosystem services in mountain landscapes. We demonstrated a spatially explicit method based on geo-tagged images from popular social media to assess revealed preferences. A spatially weighted regression showed that specific variables correspond to prominent drivers of cultural ecosystem services at the local scale. The results of this explanatory approach can be used to integrate the cultural service dimension into land planning by taking into account specific benefiting areas and by setting priorities on the ecosystems and landscape characteristics which affect the service supply. We finally concluded that the use of crowdsourced data allows identifying spatial patterns of cultural ecosystem service preferences and their association with landscape settings.PostprintPeer reviewe
Development of inventory datasets through remote sensing and direct observation data for earthquake loss estimation
This report summarizes the lessons learnt in extracting exposure information for the three study sites, Thessaloniki, Vienna and Messina that were addressed in SYNER-G. Fine scale information on exposed elements that for SYNER-G include buildings, civil engineering works and population, is one of the variables used to quantify risk. Collecting data and creating exposure inventories is a very time-demanding job and all possible data-gathering techniques should be used to address the data shortcoming problem. This report focuses on combining direct observation and remote sensing data for the development of exposure models for seismic risk assessment. In this report a summary of the methods for collecting, processing and archiving inventory datasets is provided in Chapter 2. Chapter 3 deals with the integration of different data sources for optimum inventory datasets, whilst Chapters 4, 5 and 6 provide some case studies where combinations between direct observation and remote sensing have been used. The cities of Vienna (Austria), Thessaloniki (Greece) and Messina (Italy) have been chosen to test the proposed approaches.JRC.G.5-European laboratory for structural assessmen
Planet Discoverer Interferometer (PDI) I: a potential precursor to Terrestrial Planet Finder
We consider a possible precursor interferometer to Terrestrial Planet Finder. The precursor called Planet Discoverer Interferometer (PDI) would search for broadband 10 μm radiation from possible terrestrial planets orbiting stars out to a distance of 8-10pc and at an angular separation of at least 0.1 arcseconds. There are about 20 stars of types A,F,G and K around which an Earth-analog might be detected. PDI would be able to confirm such planets by seeing their orbital motion. PDI would also be able to observe 5 μm radiation from the more massive and younger gas-giant planets around stars up to distances ∼ 150 pc, separated from their star by more than 0.05 arc seconds. It would also see the re-radiated thermal radiation of Jupiter-like planets at temperatures above ∼130K. The device would be a 15m long truss with four SIRTF-like telescopes. It would need to be in a SIRTF-like Earth-trailing orbit, and would be radiatively cooled. A very preliminary design suggest that PDI could fit into the shroud of a Delta II rocket. Similar preliminary calculations suggest that the total lifetime cost of such a mission would be under $300M. Detailed studies of this concept are in process
Telescope to Observe Planetary Systems (TOPS): a high throughput 1.2-m visible telescope with a small inner working angle
The Telescope to Observe Planetary Systems (TOPS) is a proposed space mission
to image in the visible (0.4-0.9 micron) planetary systems of nearby stars
simultaneously in 16 spectral bands (resolution R~20). For the ~10 most
favorable stars, it will have the sensitivity to discover 2 R_E rocky planets
within habitable zones and characterize their surfaces or atmospheres through
spectrophotometry. Many more massive planets and debris discs will be imaged
and characterized for the first time. With a 1.2m visible telescope, the
proposed mission achieves its power by exploiting the most efficient and robust
coronagraphic and wavefront control techniques. The Phase-Induced Amplitude
Apodization (PIAA) coronagraph used by TOPS allows planet detection at 2
lambda/d with nearly 100% throughput and preserves the telescope angular
resolution. An efficient focal plane wavefront sensing scheme accurately
measures wavefront aberrations which are fed back to the telescope active
primary mirror. Fine wavefront control is also performed independently in each
of 4 spectral channels, resulting in a system that is robust to wavefront
chromaticity.Comment: 12 pages, SPIE conference proceeding, May 2006, Orlando, Florid
The Microlensing Planet Finder: Completing the Census of Extrasolar Planets in the Milky Way
The Microlensing Planet Finder (MPF) is a proposed Discovery mission that
will complete the first census of extrasolar planets with sensitivity to
planets like those in our own solar system. MPF will employ a 1.1m aperture
telescope, which images a 1.3 sq. deg. field-of-view in the near-IR, in order
to detect extrasolar planets with the gravitational microlensing effect. MPF's
sensitivity extends down to planets of 0.1 Earth masses, and MPF can detect
Earth-like planets at all separations from 0.7AU to infinity. MPF's extrasolar
planet census will provide critical information needed to understand the
formation and frequency of extra solar planetary systems similar to our own.Comment: To appear in the Proceedings of the SPIE Astronomical Telescopes and
Instrumentation Symposium held in Glascow, Scotland, on 21-25 June, 2004. 12
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Parents with attention-deficit/hyperactivity disorder children: A needs assessment
The purpose of this study was to assess the needs of parents with ADHD children. A needs assessment study will provide information to social workers on what parents are not getting from current intervention models
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