188 research outputs found
Foundations of Trusted Autonomy
This book establishes the foundations needed to realize the ultimate goals for artificial intelligence, such as autonomy and trustworthiness. Aimed at scientists, researchers, technologists, practitioners, and students, it brings together contributions offering the basics, the challenges and the state-of-the-art on trusted autonomous systems in a single volume. The book is structured in three parts, with chapters written by eminent researchers and outstanding practitioners and users in the field. The first part covers foundational artificial intelligence technologies, while the second part covers philosophical, practical and technological perspectives on trust. Lastly, the third part presents advanced topics necessary to create future trusted autonomous systems. The book augments theory with real-world applications including cyber security, defence and space
The NextGen Model Atmosphere grid: II. Spherically symmetric model atmospheres for giant stars with effective temperatures between 3000 and 6800~K
We present the extension of our NextGen model atmosphere grid to the regime
of giant stars. The input physics of the models presented here is nearly
identical to the NextGen dwarf atmosphere models, however spherical geometry is
used self-consistently in the model calculations (including the radiative
transfer). We re-visit the discussion of the effects of spherical geometry on
the structure of the atmospheres and the emitted spectra and discuss the
results of NLTE calculations for a few selected models.Comment: ApJ, in press (November 1999), 13 pages, also available at
http://dilbert.physast.uga.edu/~yeti/PAPERS and at
ftp://calvin.physast.uga.edu/pub/preprints/NG-giants.ps.g
Bull Trout (Salvelinus confluentus) can detect conspecific pheromones in a two choice Y-maze
Two stocks of Bull Trout (Salvelinus confluentus) were tested in a two choice Y-maze to determine if they could detect pheromones from the same natal population (population specific pheromones PSP) or from a different (conspecific) population of Bull Trout (CSP). Fish from the Pack River (PR), Idaho and the Metolius River (MR), Oregon were transferred to a fish hatchery where Y-maze studies were conducted. The Y-maze was constructed to supply well water at 12°C (blank) to both arms with the temperature and discharge of each arm matched to within 0.1°C and 0.01 l/s. One arm was randomly selected to be supplied with pheromones from fish held in stock tanks. Four types of tests were conducted with each stock: 1) blank supplied to both arms; 2) PSP + blank in one arm; 3) CSP + blank in one arm; 4) PSP + blank in one arm and CSP + blank in the other. Chi Square (χ²) Goodness of Fit tests with two degrees of freedom were used to compare the frequency at which fish entered each arm to the theoretical distribution that assumed they randomly selected an arm. Both stocks exhibited no preference when blank water only was present [PR: (χ²=4.79; p=0.091; n=28); MR: (χ²=4.67; p=.097; n=27)]. Both stocks preferred the PSP arm over the blank arm during PSP tests [PR: (χ²=14.00; p\u3c0.001; n=27); MR: (χ²=21.94; p\u3c0.001; n=28)]. Both stocks preferred the CSP arm over the blank arm during CSP tests [PR: (χ²=15.07; p\u3c0.001; n=26); MR: (χ²=16.72; p\u3c0.001; n=31)]. During the PSP vs. CSP tests, both PR and MR spent equivalent frequency in PSP and CSP arms therefore exhibited no preference [PR: (χ²=2.96; p=0.227; n=29); MR: (χ²=4.90; p=0.086; n=31)]. These results showed Bull Trout could detect pheromones from other Bull Trout but could not differentiate between PSPs and CSPs
Co-operatives create worker power [Moderated Conversation]
This conversation will focus on the ways in which cooperatives create worker power in the US and Europe To cite this talk: Scholz, T., O’Brien, D., Spicer, J., Lurie, R., & Calzada, I. (2021), Can Co-operatives Build Worker Power? Platform Co-operativism Consortium RadFest, The New School. 6th April
Developing a Trusted Human-AI Network for Humanitarian Benefit
Humans and artificial intelligences (AI) will increasingly participate digitally and physically in conflicts yet there is a lack of trusted communications across agents and platforms. For example, humans in disasters and conflict already use messaging and social media to share information, however, international humanitarian relief organisations treat this information as unverifiable and untrustworthy. AI may reduce the ‘fog-of-war’ and improve outcomes, however current AI implementations are often brittle, have a narrow scope of application and wide ethical risks. Meanwhile, human error causes significant civilian harms even by combatants committed to complying with international humanitarian law. AI offers an opportunity to help reduce the tragedy of war and better deliver humanitarian aid to those who need it. However, to be successful, these systems must be trusted by humans and their information systems, overcoming flawed information flows in conflict and disaster zones that continue to be marked by intermittent communications, poor situation awareness, mistrust and human errors. In this paper, we consider the integration of a communications protocol (the ‘Whiteflag protocol’), distributed ledger technology, and information fusion with artificial intelligence (AI), to improve conflict communications called “Protected Assurance Understanding Situation & Entities” PAUSE. Such a trusted human-AI communication network could provide accountable information exchange regarding protected entities, critical infrastructure; humanitarian signals and status updates for humans and machines in conflicts. Trust-based information fusion provides resource-efficient use of diverse data sources to increase the reliability of reports. AI can be used to catch human mistakes and complement human decision making, while human judgment can direct and override AI recommendations. We examine several case studies for the integration of these technologies into a trusted human-AI network for humanitarian benefit including mapping a conflict zone with civilians and combatants in real time, preparation to avoid incidents and using the network to manage misinformation
The Host Galaxy and Redshift of the Repeating Fast Radio Burst FRB 121102
The precise localization of the repeating fast radio burst (FRB 121102) has
provided the first unambiguous association (chance coincidence probability
) of an FRB with an optical and persistent radio
counterpart. We report on optical imaging and spectroscopy of the counterpart
and find that it is an extended ()
object displaying prominent Balmer and [OIII] emission lines. Based on the
spectrum and emission line ratios, we classify the counterpart as a
low-metallicity, star-forming, AB mag dwarf galaxy at a
redshift of , corresponding to a luminosity distance of 972 Mpc.
From the angular size, the redshift, and luminosity, we estimate the host
galaxy to have a diameter kpc and a stellar mass of
, assuming a mass-to-light ratio between 2 to
3. Based on the H flux, we estimate the star
formation rate of the host to be and a
substantial host dispersion measure depth .
The net dispersion measure contribution of the host galaxy to FRB 121102 is
likely to be lower than this value depending on geometrical factors. We show
that the persistent radio source at FRB 121102's location reported by Marcote
et al (2017) is offset from the galaxy's center of light by 200 mas and
the host galaxy does not show optical signatures for AGN activity. If FRB
121102 is typical of the wider FRB population and if future interferometric
localizations preferentially find them in dwarf galaxies with low metallicities
and prominent emission lines, they would share such a preference with long
gamma ray bursts and superluminous supernovae.Comment: 12 pages, 3 figures, Published in ApJ Letters. V2: Corrected mistake
in author lis
Single-cell and metagenomic analyses indicate a fermentative and saccharolytic lifestyle for members of the OP9 lineage
OP9 is a yet-uncultivated bacterial lineage found in geothermal systems, petroleum reservoirs, anaerobic digesters and wastewater treatment facilities. Here we use single-cell and metagenome sequencing to obtain two distinct, nearly complete OP9 genomes, one constructed from single cells sorted from hot spring sediments and the other derived from binned metagenomic contigs from an in situ-enriched cellulolytic, thermophilic community. Phylogenomic analyses support the designation of OP9 as a candidate phylum for which we propose the name ‘Atribacteria’. Although a plurality of predicted proteins is most similar to those from Firmicutes, the presence of key genes suggests a diderm cell envelope. Metabolic reconstruction from the core genome suggests an anaerobic lifestyle based on sugar fermentation by Embden–Meyerhof glycolysis with production of hydrogen, acetate and ethanol. Putative glycohydrolases and an endoglucanase may enable catabolism of (hemi)cellulose in thermal environments. This study lays a foundation for understanding the physiology and ecological role of the ‘Atribacteria’.United States. National Aeronautics and Space Administration (Exobiology Grant EXO-NNX11AR78G)National Science Foundation (U.S.) (Grant MCB 0546865)National Science Foundation (U.S.) (Grant OISE 0968421)United States. Dept. of Energy (Grant DE-EE-0000716)Nevada Renewable Energy ConsortiumUnited States. Dept. of Energy. Office of Science. Joint Genome Institute (Contract DE-AC02-05CH11231
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Changing hydroclimate dynamics and the 19th to 20th century wetting trend in the English Channel region of northwest Europe
Northwestern Europe has experienced a trend of increasingly wet winters over the past 150 years, with few explanations for what may have driven this hydroclimatic change. Here we use the Old World Drought Atlas (OWDA), a tree-ring based reconstruction of the self-calibrating Palmer Drought Severity Index (scPDSI), to examine this wetting trend and place it in a longer hydroclimatic context. We find that scPDSI variability in northwestern Europe is strongly correlated with the leading mode of the OWDA during the last millennium (1000–2012). This leading mode, here named the ‘English Channel’ (EC) mode, has pronounced variability on interannual to centennial timescales and has an expression in scPDSI similar to that of the East Atlantic teleconnection pattern. A shift in the EC mode from a prolonged negative phase to more neutral conditions during the 19th and 20th centuries is associated with the wetting trend over its area of influence in England, Wales, and much of northern continental Europe. The EC mode is the dominant scPDSI mode from approximately 1000–1850, after which its dominance waned in favor of the secondary ‘North–South’ (NS) mode, which has an expression in scPDSI similar to that of the winter North Atlantic Oscillation (NAO). We examine the dynamical nature of both of these modes and how they vary on interannual to centennial timescales. Our results provide insight into the nature of hydroclimate variability in Europe before the widespread availability of instrumental observations
The 60 pc Environment of FRB 20180916B
Fast Radio Burst FRB 20180916B in its host galaxy SDSS J015800.28+654253.0 at
149 Mpc is by far the closest-known FRB with a robust host galaxy association.
The source also exhibits a 16.35-day period in its bursting. Here we present
optical and infrared imaging as well as integral field spectroscopy
observations of FRB 20180916B with the WFC3 camera on the Hubble Space
Telescope and the MEGARA spectrograph on the 10.4-m Gran Telescopio Canarias.
The 60-90 milliarcsecond (mas) resolution of the Hubble imaging, along with the
previous 2.3-mas localization of FRB 20180916B, allow us to probe its
environment with a 30-60 pc resolution. We constrain any point-like
star-formation or HII region at the location of FRB 20180916B to have an
H luminosity and, correspondingly, constrain the local
star-formation rate to be . The
constraint on H suggests that possible stellar companions to FRB
20180916B should be of a cooler, less massive spectral type than O6V. FRB
20180916B is 250 pc away (in projected distance) from the brightest pixel of
the nearest young stellar clump, which is \,pc in size (full-width at
half maximum). With the typical projected velocities of pulsars, magnetars, or
neutron stars in binaries (60-750 km s), FRB 20180916B would need 800
kyr to 7 Myr to traverse the observed distance from its presumed birth site.
This timescale is inconsistent with the active ages of magnetars (
kyr). Rather, the inferred age and observed separation are compatible with the
ages of high-mass X-ray binaries and gamma-ray binaries, and their separations
from the nearest OB associations.Comment: Updated version: Updated Figure 2. 16 pages, 4 figures, 1 table.
Published in ApJ Letters. Comments welcom
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A quantitative hydroclimatic context for the European Great Famine of 1315-17
The European Great Famine of 1315–1317 triggered one of the worst population collapses in European history and ranks as the single worst European famine in mortality as a proportion of population. Historical records point to torrential rainfall, land saturation, crop failure, and prolonged flooding as important causes of the famine. Here we use the tree-ring based Old World Drought Atlas (OWDA) to show that the average of each growing season preceding the Great Famine years (1314–1316) was the fifth wettest over Europe from 1300 to 2012 C.E. The spatial and temporal characteristics of our OWDA-estimated anomalies are in excellent agreement with available historical accounts. We also characterize a mode of European hydroclimate variability that is associated with the Great Famine, which we term the “Great Famine mode.” This mode emerges as the leading mode of European hydroclimate variability from 1300–2012 and is strongly associated with extreme wet and dry events in Europe over the last millennium
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