85 research outputs found
Moving earth and building monuments at the Carson Mounds Site, Coahoma County, Mississippi
The application of combined techniques such as aerial imagery, sediment coring, down-hole magnetic susceptibility, and mechanized trench excavation can provide critical information on landscape formation and mound stratigraphy, specifically if they can be used to understand mound sequences and development. This paper reviews preliminary findings from recent coring and test excavations at the Carson mounds site (22CO505) in Coahoma County, Mississippi. Aerial imagery assisted in the characterization of a crevasse ridge flood deposit underlying the site and detailed field descriptions of the pedology corroborated its existence. Subsequent sediment coring and trench excavation revealed the nature of flooding in prehistory, indicating that high-intensity floods were responsible for the formation of the crevasse ridge and that lower intensity floods were potentially responsible for interruptions in mound building at the site. This suggests that the Carson settlement was initiated on an actively flooding landform. Down-hole magnetic susceptibility correlated effectively with the pedology; however, it also helped discern anthropogenic surfaces (i.e., occupational layers) that are difficult to identify visually, such as those we found in Mound C. Findings from this pilot study demonstrate the utility of sediment coring and magnetic susceptibility as effective and feasible methods for developing hypothesis-driven research
Integrating geoarchaeology and magnetic susceptibility at three shell mounds: a pilot study from Mornington Island, Gulf of Carpentaria, Australia
In coastal areas of the globe, open shell matrix sites are commonly used to establish regional chronologies of human occupation and identify patterns of cultural change, particularly for the Holocene, post-sea-level stabilisation period. Despite this, many basic sedimentary analyses that are routinely applied to rockshelter deposits (e.g. geophysical characterisation, particle size etc) are rarely applied to these sites. Magnetic susceptibility, occasionally used in rockshelters, has never been used to investigate shell matrix sites in Australia, despite several international studies identifying its efficacy for other types of open sites. This paper reports a pilot project applying a range of conventional sedimentary and archaeological analyses, as well as magnetic susceptibility at three anthropogenic shell mounds on Mornington Island, Gulf of Carpentaria, Australia. Results are compared to, firstly, assess site integrity and, secondly, to ascertain whether magnetic signatures are related to cultural or natural site formation processes. The results establish that the mounds were repeatedly visited, despite the archaeological evidence, including radiocarbon ages, suggesting effectively ‘instantaneous’ deposition. This has important implications for studies of other shell mounds where the limitations of radiocarbon dating precision may also mask multiple deposition events
COVID-19 as a global challenge: towards an inclusive and sustainable future
COVID-19 is a global challenge that demands researchers, policy makers, and governments address multiple dimensions which go far beyond the implications of this pandemic for health and wellbeing. Just as the UN Sustainable Development Goals call for focus on the connections between development policy sectors, the pandemic has exposed the complex global interdependencies that underpin economies and highlighted fault lines in societal structures that perpetuate ethnic, economic, social, and gender inequalities.Here,wehighlightthepandemic’semerging potential consequences for achieving sustainable development with respect to the six global challenge areas we collectively address at the UK Research and Innovation’s Global Challenges Research Fund:1 food systems; education; cities and sustainable infrastructure; security, protracted conflict, refugee crises, and forced displacement; environmental resilience; and global health. As the immediate health consequences of the pandemic unfold and begin to be superseded by the impact of public health containment measures, we call for a refocusing of research and action not only to mitigate these impacts but to build sustainability and strengthened resilience into future recovery.COVID-19 is a global challenge that demands researchers, policy makers, and governments address multiple dimensions which go far beyond the implications of this pandemic for health and wellbeing. Just as the UN Sustainable Development Goals call for focus on the connections between development policy sectors, the pandemic has exposed the complex global interdependencies that underpin economies and highlighted fault lines in societal structures that perpetuate ethnic, economic, social, and gender inequalities. Here, we highlight the pandemic’s emerging potential consequences for achieving sustainable development with respect to the six global challenge areas we collectively address at the UK Research and Innovation’s Global Challenges Research Fund:1 food systems; education; cities and sustainable infrastructure; security, protracted conflict, refugee crises, and forced displacement; environmental resilience; and global health. As the immediate health consequences of the pandemic unfold and begin to be superseded by the impact of public health containment measures, we call for a refocusing of research and action not only to mitigate these impacts but to build sustainability and strengthened resilience into future recovery
A Holocene sequence from Walufeni Cave, Southern Highlands Province, and its implications for the settlement of the Great Papuan Plateau, Papua New Guinea
This paper presents preliminary results from the 2019 excavations at Walufeni Cave, at the eastern end of the Great Papuan Plateau (GPP) in western Papua New Guinea. Preliminary dating and analysis of the unfinished excavations at Walufeni Cave span the Holocene and probably continue into the Late Pleistocene, confirming the presence of people on the Plateau from at least the Early Holocene and potentially much earlier. The data presented here offer a site-specific model of early intensive site use from at least 10,000 years ago, then ephemeral use, followed by a sustained Late Holocene occupation. Although there are significant changes in the quantity of material discard over time, there is little evidence for significant change in the subsistence base or technology, reflecting a degree of relative homogeneity until the Late Holocene, when we see the introduction of pig, a change of focus in the plant economy and the presence of marine shell from the southern coast
Managing Dynamic User Communities in a Grid of Autonomous Resources
One of the fundamental concepts in Grid computing is the creation of Virtual
Organizations (VO's): a set of resource consumers and providers that join
forces to solve a common problem. Typical examples of Virtual Organizations
include collaborations formed around the Large Hadron Collider (LHC)
experiments. To date, Grid computing has been applied on a relatively small
scale, linking dozens of users to a dozen resources, and management of these
VO's was a largely manual operation. With the advance of large collaboration,
linking more than 10000 users with a 1000 sites in 150 counties, a
comprehensive, automated management system is required. It should be simple
enough not to deter users, while at the same time ensuring local site autonomy.
The VO Management Service (VOMS), developed by the EU DataGrid and DataTAG
projects[1, 2], is a secured system for managing authorization for users and
resources in virtual organizations. It extends the existing Grid Security
Infrastructure[3] architecture with embedded VO affiliation assertions that can
be independently verified by all VO members and resource providers. Within the
EU DataGrid project, Grid services for job submission, file- and database
access are being equipped with fine- grained authorization systems that take VO
membership into account. These also give resource owners the ability to ensure
site security and enforce local access policies. This paper will describe the
EU DataGrid security architecture, the VO membership service and the local site
enforcement mechanisms Local Centre Authorization Service (LCAS), Local
Credential Mapping Service(LCMAPS) and the Java Trust and Authorization
Manager.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics
(CHEP03), La Jolla, Ca, USA, March 2003, 7 pages, LaTeX, 5 eps figures. PSN
TUBT00
AnBx - Security Protocols Design and Verification
Designing distributed protocols is challenging, as it requires actions at very different levels: from the choice of network-level mechanisms to protect the exchange of sensitive data, to the definition of structured interaction patterns to convey application-specific guarantees. Current security infrastructures provide very limited support for the specification of such guarantees. As a consequence, the high-level security properties of a protocol typically must often be hard-coded explicitly, in terms of low-level cryptographic notions and devices which clutter the design and undermine its scalability and robustness. To counter these problems, we propose an extended Alice & Bob notation for protocol narrations (AnBx) to be employed for a purely declarative modelling of distributed protocols. These abstractions provide a compact specification of the high-level security guarantees they convey, and help shield the design from the details of the underlying cryptographic infrastructure. We discuss an implementation of the abstractions based on a translation from the AnBx notation to the AnB language supported by the OFMC [1,2] verification tool. We show the practical effectiveness of our approach by revisiting the iKP e-payment protocols, and showing that the security goals achieved by our declarative specification outperform those offered by the original protocols
Retired A Stars and Their Companions VI. A Pair of Interacting Exoplanet Pairs Around the Subgiants 24 Sextanis and HD200964
We report radial velocity measurements of the G-type subgiants 24 Sextanis
(=HD90043) and HD200964. Both are massive, evolved stars that exhibit periodic
variations due to the presence of a pair of Jovian planets. Photometric
monitoring with the T12 0.80m APT at Fairborn Observatory demonstrates both
stars to be constant in brightness to <= 0.002 mag, thus strengthening the
planetary interpretation of the radial velocity variations. 24 Sex b,c have
orbital periods of 453.8 days and 883~days, corresponding to semimajor axes
1.333 AU and 2.08 AU, and minimum masses (Msini) 1.99 Mjup and 0.86 Mjup,
assuming a stellar mass 1.54 Msun. HD200964 b,c have orbital periods of 613.8
days and 825 days, corresponding to semimajor axes 1.601 AU and 1.95 AU, and
minimum masses 1.85 Mjup and 0.90 Mjup, assuming M* = 1.44 Msun. We also carry
out dynamical simulations to properly account for gravitational interactions
between the planets. Most, if not all, of the dynamically stable solutions
include crossing orbits, suggesting that each system is locked in a mean motion
resonance that prevents close encounters and provides long-term stability. The
planets in the 24 Sex system likely have a period ratio near 2:1, while the
HD200964 system is even more tightly packed with a period ratio close to 4:3.
However, we caution that further radial velocity observations and more detailed
dynamical modelling will be required to provide definitive and unique orbital
solutions for both cases, and to determine whether the two systems are truly
resonant.Comment: AJ accepte
Retired A Stars and Their Companions. III. Comparing the Mass-Period Distributions of Planets Around A-Type Stars and Sun-Like Stars
We present an analysis of ~5 years of Lick Observatory radial velocity
measurements targeting a uniform sample of 31 intermediate-mass subgiants (1.5
< M*/Msun < 2.0) with the goal of measuring the occurrence rate of Jovian
planets around (evolved) A-type stars and comparing the distributions of their
orbital and physical characteristics to those of planets around Sun-like stars.
We provide updated orbital solutions incorporating new radial velocity
measurements for five known planet-hosting stars in our sample; uncertainties
in the fitted parameters are assessed using a Markov Chain Monte Carlo method.
The frequency of Jovian planets interior to 3 AU is 26 (+9,-8)%, which is
significantly higher than the ~5-10% frequency observed around solar-mass
stars. The median detection threshold for our sample includes minimum masses
down to {0.2, 0.3, 0.5, 0.6, 1.3} MJup within {0.1, 0.3, 0.6, 1.0, 3.0} AU. To
compare the properties of planets around intermediate-mass stars to those
around solar-mass stars we synthesize a population of planets based on the
parametric relationship dN ~ M^{alpha}P^{beta} dlnM dlnP, the observed planet
frequency, and the detection limits we derived. We find that the values of
alpha and beta for planets around solar-type stars from Cumming et al. fail to
reproduce the observed properties of planets in our sample at the 4 sigma
level, even when accounting for the different planet occurrence rates. Thus,
the properties of planets around A stars are markedly different than those
around Sun-like stars, suggesting that only a small (~ 50%) increase in stellar
mass has a large influence on the formation and orbital evolution of planets.Comment: Accepted by the Astrophysical Journal; 15 pages, 15 figure
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