Tracing Maize History in Northern Iroquoia Through Radiocarbon Date Summed Probability Distributions

2022 ◽  
Author(s):  
John P. Hart
Keyword(s):  
Probability Distributions ◽  
Radiocarbon Date

Plants and Subsistence during the Fluted-Point Period of the Northeast

2021 ◽  
pp. 1-9
Author(s):  
Nathaniel R. Kitchel ◽  
Madeline E. Mackie
Keyword(s):  
North America ◽  
Probability Distributions ◽  
Diet Breadth ◽  
Radiocarbon Date ◽  
Northeastern North America ◽  
Plant Foods ◽  
Macrobotanical Remains ◽  
Caribou Hunting

The role of plant foods during the fluted-point period (FPP) of North America is contested. Central to this debate is whether the scarcity of FPP macrobotanical materials stems from poor preservation of archaeological features and the macrobotanical remains they might contain or from the limited use of plants during the FPP. Employing summed probability distributions of radiocarbon date frequencies in northeastern North America, we find that FPP hearths are as common as expected, given the small number of well-dated FPP sites in the region. A second comparison shows that northeastern FPP hearths contain macrobotanical remains at a higher frequency than hearths from a region with better preservation and where small seeds formed a part of the diet. The macrobotanical materials so far recovered from FPP hearths in the Northeast show that plant foods contributed to diets during the FPP but that the plant diet breadth was relatively narrow, consistent with a specialized caribou hunting lifeway.

Asteroid and Comet Impact Speeds upon Mars: Significance for Panspermia and the Supply of Organics

1997 ◽  
Vol 161 ◽  
pp. 197-201 ◽  
Author(s):  
Duncan Steel
Keyword(s):  
Probability Distributions ◽  
Regions Of Interest ◽  
Significant Fraction ◽  
Organic Chemicals ◽  
Impact Speed ◽  
The Mean ◽  
The Impact

AbstractWhilst lithopanspermia depends upon massive impacts occurring at a speed above some limit, the intact delivery of organic chemicals or other volatiles to a planet requires the impact speed to be below some other limit such that a significant fraction of that material escapes destruction. Thus the two opposite ends of the impact speed distributions are the regions of interest in the bioastronomical context, whereas much modelling work on impacts delivers, or makes use of, only the mean speed. Here the probability distributions of impact speeds upon Mars are calculated for (i) the orbital distribution of known asteroids; and (ii) the expected distribution of near-parabolic cometary orbits. It is found that cometary impacts are far more likely to eject rocks from Mars (over 99 percent of the cometary impacts are at speeds above 20 km/sec, but at most 5 percent of the asteroidal impacts); paradoxically, the objects impacting at speeds low enough to make organic/volatile survival possible (the asteroids) are those which are depleted in such species.

A Mesolithic Scatter from Littlehill Bridge, Girvan, Ayrshire

2001 ◽  
Vol 23 (1) ◽  
pp. 1-14 ◽  
Author(s):  
GAVIN MACGREGOR ◽  
MICHAEL DONNELLY ◽  
J. MILLER ◽  
S. RAMSAY ◽  
D. ALLDRITT
Keyword(s):  
Radiocarbon Date

An assemblage of 366 lithics was recovered during the characterisation of archaeological deposits, from deposits which appear to represent a scooped occupation. Analysis of the assemblage and a radiocarbon date range of 6355-6012 cal BC indicate that it belongs to the Mesolithic. The site is significant because it is the first Mesolithic material to have been recovered by excavation in the Girvan area. It also provides additional evidence for a class of semipermanent Mesolithic sites consisting of shallow scoops surrounded by turf or earthen banks.

Excavation of sub-peat agricultural features on Machrie Moor, Arran

2000 ◽  
Vol 22 (2) ◽  
pp. 179-186
Author(s):  
KEVIN J TAYLOR ◽  
TARA HUNTER
Keyword(s):  
Radiocarbon Date ◽  
Agricultural Activity ◽  
Early Agriculture

Excavations near two upstanding hut circles overlooking Machrie Moor revealed traces of early agriculture in the form of narrow, or 'cord' rig associated with a small cairn. Sealed beneath this were traces of earlier agricultural activity in the form of ard marks. A radiocarbon date from a basal sample of the overlying peat spanned the fifth to seventh centuries AD.

An Accelerated Cue Combination Principle Accounts for Multi-cue Depth Perception

2020 ◽  
Vol 3 (1) ◽  
pp. 10501-1-10501-9
Author(s):  
Christopher W. Tyler
Keyword(s):  
Belief Propagation ◽  
Probability Distributions ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Fusion Model ◽  
Cue Combination ◽  
Depth Estimate ◽  
Appropriate Behavior ◽  
Depth Cues ◽  
Bayesian Averaging

Abstract For the visual world in which we operate, the core issue is to conceptualize how its three-dimensional structure is encoded through the neural computation of multiple depth cues and their integration to a unitary depth structure. One approach to this issue is the full Bayesian model of scene understanding, but this is shown to require selection from the implausibly large number of possible scenes. An alternative approach is to propagate the implied depth structure solution for the scene through the “belief propagation” algorithm on general probability distributions. However, a more efficient model of local slant propagation is developed as an alternative.The overall depth percept must be derived from the combination of all available depth cues, but a simple linear summation rule across, say, a dozen different depth cues, would massively overestimate the perceived depth in the scene in cases where each cue alone provides a close-to-veridical depth estimate. On the other hand, a Bayesian averaging or “modified weak fusion” model for depth cue combination does not provide for the observed enhancement of perceived depth from weak depth cues. Thus, the current models do not account for the empirical properties of perceived depth from multiple depth cues.The present analysis shows that these problems can be addressed by an asymptotic, or hyperbolic Minkowski, approach to cue combination. With appropriate parameters, this first-order rule gives strong summation for a few depth cues, but the effect of an increasing number of cues beyond that remains too weak to account for the available degree of perceived depth magnitude. Finally, an accelerated asymptotic rule is proposed to match the empirical strength of perceived depth as measured, with appropriate behavior for any number of depth cues.

Age and architecture of the largest African Baobabs from Mayotte, France

2020 ◽  
Author(s):  
Adrian Patrut ◽  
Roxana Patrut ◽  
Laszlo Rakosy ◽  
Karl von Reden
Keyword(s):  
Life Cycle ◽  
Radiocarbon Dating ◽  
Cluster Structure ◽  
Radiocarbon Date ◽  
General State ◽  
Adansonia Digitata ◽  
Open Ring ◽  
The Indian Ocean ◽  
Ring Shaped Structure ◽  
Comoro Islands

The volcanic Comoro Islands, located in the Indian Ocean in between mainland Africa and Madagascar, host several thousand African baobabs (Adansonia digitata). Most of them are found in Mayotte, which currently belongs to France, as an overseas department. We report the investigation of the largest two baobabs of Mayotte, the Big baobab of Musical Plage and the largest baobab of Plage N’Gouja. The Big baobab of Musical Plage exhibits a cluster structure and consists of 5 fused stems, out of which 4 are common stems and one is a false stem. The baobab of Plage N’Gouja has an open ring-shaped structure and consists of 7 partially fused stems, out of which 3 stems are large and old, while 4 are young. Several wood samples were collected from both baobabs and analyzed via radiocarbon dating. The oldest dated sample from the baobab of Musical Plage has a radiocarbon date of 275 ± 25 BP, which corresponds to a calibrated calendar age of 365 ± 15 yr. On its turn, the oldest sample from Plage N’Gouja has a radiocarbon date of 231 ± 20 BP, which translates into a calibrated age of 265 ± 15 yr. These results indicate that the Big baobab of Musical Plage is around 420 years old, while the baobab of Plage N’Gouja has an age close to 330 years. In present, both baobabs are in a general state of deterioration with many broken or damaged branches, and the Baobab of Plage N’Gouja has several missing stems. These observations suggest that the two baobabs are in decline and, most likely, close to the end of their life cycle.

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