299 research outputs found
PDF Accessibility of Research Papers: What Tools are Needed for Assessment and Remediation?
Trillions of documents online are in PDF format, but only a small amount of these PDF documents include the necessary markup to make them accessible for people with disabilities. This paper presents the results of three related data collection efforts: a survey (with 61 participants), interviews (with 6 participants), and usability testing (with 6 participants), to learn more about what tools are needed for content contributors, to assist them in the assessment and remediation of accessibility in PDF documents. The paper provides suggested features and usability needed for software tools to support PDF document accessibility, as well as implications for content creators, scientific publishers, as well as the creator of the PDF format, Adobe
All Six Planets Known to Orbit Kepler-11 Have Low Densities
The Kepler-11 planetary system contains six transiting planets ranging in
size from 1.8 to 4.2 times the radius of Earth. Five of these planets orbit in
a tightly-packed configuration with periods between 10 and 47 days. We perform
a dynamical analysis of the system based upon transit timing variations
observed in more than three years of \ik photometric data. Stellar parameters
are derived using a combination of spectral classification and constraints on
the star's density derived from transit profiles together with planetary
eccentricity vectors provided by our dynamical study. Combining masses of the
planets relative to the star from our dynamical study and radii of the planets
relative to the star from transit depths together with deduced stellar
properties yields measurements of the radii of all six planets, masses of the
five inner planets, and an upper bound to the mass of the outermost planet,
whose orbital period is 118 days. We find mass-radius combinations for all six
planets that imply that substantial fractions of their volumes are occupied by
constituents that are less dense than rock. The Kepler-11 system contains the
lowest mass exoplanets for which both mass and radius have been measured.Comment: 39 pages, 10 figure
CSS Antimony Selenide Film Morphology and High Efficiency PV Devices
Knowledge of close-space sublimation (CSS) Sb 2 Se 3 growth conditions is vital for proper understanding of PV performance, and optimization of Sb 2 Se 3 devices. In this work, various growth parameters have been studied and the resulting Sb 2 Se 3 films have been characterized using SEM, XRD and optical transmission measurements, thus illustrating the desired properties for high device performance. PV devices were fabricated using TiO 2 as a window layer combined with P3HT or PTB7 as the hole transport material, resulting in V oc =0.42 V, J sc =33.4 mAcm -2 , FF = 43.2% and PCE = 6.06% for P3HT
Validation of Kepler's Multiple Planet Candidates. III: Light Curve Analysis & Announcement of Hundreds of New Multi-planet Systems
The Kepler mission has discovered over 2500 exoplanet candidates in the first
two years of spacecraft data, with approximately 40% of them in candidate
multi-planet systems. The high rate of multiplicity combined with the low rate
of identified false-positives indicates that the multiplanet systems contain
very few false-positive signals due to other systems not gravitationally bound
to the target star (Lissauer, J. J., et al., 2012, ApJ 750, 131). False
positives in the multi- planet systems are identified and removed, leaving
behind a residual population of candidate multi-planet transiting systems
expected to have a false-positive rate less than 1%. We present a sample of 340
planetary systems that contain 851 planets that are validated to substantially
better than the 99% confidence level; the vast majority of these have not been
previously verified as planets. We expect ~2 unidentified false-positives
making our sample of planet very reliable. We present fundamental planetary
properties of our sample based on a comprehensive analysis of Kepler light
curves and ground-based spectroscopy and high-resolution imaging. Since we do
not require spectroscopy or high-resolution imaging for validation, some of our
derived parameters for a planetary system may be systematically incorrect due
to dilution from light due to additional stars in the photometric aperture.
None the less, our result nearly doubles the number of verified exoplanets.Comment: 138 pages, 8 Figures, 5 Tables. Accepted for publications in the
Astrophysical Journa
The practice of cultural ecology: network connectivity in the creative economy
© 2016 Informa UK Limited, trading as Taylor & Francis Group. ABSTRACT: This paper reflects on approaches to collaborative knowledge exchange projects between UK universities and the creative economy. It develops a preliminary account of cultural ecology as a systematic approach to producing impact in the creative economy. It argues that such an approach is a powerful way to aggregate micro-businesses and small and medium sized enterprises in a meaningful network of new relationships. The paper uses social network analysis software to begin to visualise the pattern of relationships that constitute the ecosystem. The paper reports on the work of the Research and Enterprise for Arts and Creative Technologies Hub, one of four Knowledge Exchange Hubs for the Creative Economy established by the Arts and Humanities Research Council
Chemical etching of Sb2Se3 solar cells: surface chemistry and back contact behaviour
The effect of (NH4)2S and CS2 chemical etches on surface chemistry and contacting in Sb2Se3 solar cells was investigated via a combination of x-ray photoemission spectroscopy (XPS) and photovoltaic device analysis. Thin film solar cells were produced in superstrate configuration with an absorber layer deposited by close space sublimation. Devices of up to 5.7% efficiency were compared via currentâvoltage measurements (JâV) and temperature-dependent currentâvoltage (JâVâT) analysis. XPS analysis demonstrated that both etching processes were successful in removing Sb2O3 contamination, while there was no decrease in free elemental selenium content by either etch, in contrast to prior work. Using JâVâT analysis the removal of Sb2O3 at the back surface in etched samples was found to improve contacting by reducing the potential barrier at the back contact from 0.43 eV to 0.26 eV and lowering the series resistance. However, JâV data showed that due to the decrease in shunt resistance and short-circuit current as a result of etching, the devices show a lower efficiency following both etches, despite a lowering of the series resistance. Further optimisation of the etching process yielded an improved efficiency of 6.6%. This work elucidates the role of surface treatments in Sb2Se3 devices and resolves inconsistencies in previously published works
Incorporating new approach methodologies into regulatory nonclinical pharmaceutical safety assessment
© 2023 The Author(s). ALTEX. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/New approach methodologies (NAMs) based on human biology enable the assessment of adverse biological effects of pharmaceuticals and other chemicals. Currently, however, it is unclear how NAMs should be used during drug development to improve human safety evaluation. A series of 5 workshops with 13 international experts (regulators, preclinical scientists, and NAMs developers) was conducted to identify feasible NAMs and to discuss how to exploit them in specific safety assessment contexts. Participants generated four âmapsâ of how NAMs can be exploited in the safety assessment of the liver, respiratory, cardiovascular, and central nervous systems. Each map shows relevant endpoints measured and tools used (e.g., cells, assays, platforms), and highlights gaps where further development and validation of NAMs remains necessary. Each map addresses the fundamental scientific requirements for the safety assessment of that organ system, providing users with guidance on the selection of appropriate NAMs. In addition to generating the maps, participants offered suggestions for encouraging greater NAM adoption within drug development and their inclusion in regulatory guidelines. A specific recommendation was that pharmaceutical companies should be more transparent about how they use NAMs in-house. As well as giving guidance for the four organ systems, the maps provide a template that could be used for additional organ safety testing contexts. Moreover, their conversion to an interactive format would enable users to drill down to the detail necessary to answer specific scientific and regulatory questions.Peer reviewe
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