Learning Silhouette Features for Control of Human Motion

We present a vision-based performance interface for controlling animated human characters. The system interactively combines information about the user's motion contained in silhouettes from three viewpoints with domain knowledge contained in a motion capture database to produce an animation of high quality. Such an interactive system might be useful for authoring, for teleconferencing, or as a control interface for a character in a game. In our implementation, the user performs in front of three video cameras; the resulting silhouettes are used to estimate his orientation and body configuration based on a set of discriminative local features. Those features are selected by a machine-learning algorithm during a preprocessing step. Sequences of motions that approximate the user's actions are extracted from the motion database and scaled in time to match the speed of the user's motion. We use swing dancing, a complex human motion, to demonstrate the effectiveness of our approach. We compare our results to those obtained with a set of global features, Hu moments, and ground truth measurements from a motion capture system.Engineering and Applied Science

Punishment and psychopathy: a case-control functional MRI investigation of reinforcement learning in violent antisocial personality disordered men

Background Men with antisocial personality disorder show lifelong abnormalities in adaptive decision making guided by the weighing up of reward and punishment information. Among men with antisocial personality disorder, modifi cation of the behaviour of those with additional diagnoses of psychopathy seems particularly resistant to punishment. Methods We did a case-control functional MRI (fMRI) study in 50 men, of whom 12 were violent off enders with antisocial personality disorder and psychopathy, 20 were violent off enders with antisocial personality disorder but not psychopathy, and 18 were healthy non-off enders. We used fMRI to measure brain activation associated with the representation of punishment or reward information during an event-related probabilistic response-reversal task, assessed with standard general linear-model-based analysis. Findings Offenders with antisocial personality disorder and psychopathy displayed discrete regions of increased activation in the posterior cingulate cortex and anterior insula in response to punished errors during the task reversal phase, and decreased activation to all correct rewarded responses in the superior temporal cortex. This finding was in contrast to results for off enders without psychopathy and healthy non-off enders. Interpretation Punishment prediction error signalling in off enders with antisocial personality disorder and psychopathy was highly atypical. This finding challenges the widely held view that such men are simply characterised by diminished neural sensitivity to punishment. Instead, this fi nding indicates altered organisation of the information processing system responsible for reinforcement learning and appropriate decision making. This difference between violent offenders with antisocial personality disorder with and without psychopathy has implications for the causes of these disorders and for treatment approaches

Centuries of Marine Radiocarbon Reservoir Age Variation Within Archaeological Mesodesma donacium Shells From Southern Peru

Mollusk shells provide brief (\u3c5 yr per shell) records of past marine conditions, including marine radiocarbon reservoir age (R) and upwelling. We report 21 14C ages and R calculations on small (~2 mg) samples from 2 Mesodesma donacium (surf clam) shells. These shells were excavated from a semi-subterranean house floor stratum 14C dated to 7625 ± 35 BP at site QJ-280, Quebrada Jaguay, southern Peru. The ranges in marine 14C ages (and thus R) from the 2 shells are 530 and 170 14C yr; R from individual aragonite samples spans 130 ± 60 to 730 ± 170 14C yr. This intrashell 14C variability suggests that 14C dating of small (time-slice much less than 1 yr) marine samples from a variable-R (i.e. variable-upwelling) environment may introduce centuries of chronometric uncertainty

Annual Variation in Atmospheric 14C between 1700 BC and 1480 BC

In 2018 Pearson et al. published a new sequence of annual radiocarbon (14C) data derived from oak (Quercus sp.) trees from Northern Ireland and bristlecone pine (Pinus longaeva) from North America across the period 1700–1500 BC. The study indicated that the more highly resolved shape of an annually based calibration dataset could improve the accuracy of 14C calibration during this period. This finding had implications for the controversial dating of the eruption of Thera in the Eastern Mediterranean. To test for interlaboratory variation and improve the robustness of the annual dataset for calibration purposes, we have generated a replicate sequence from the same Irish oaks at ETH Zürich. These data are compatible with the Irish oak 14C dataset previously produced at the University of Arizona and are used (along with additional data) to examine inter-tree and interlaboratory variation in multiyear annual 14C time-series. The results raise questions about regional 14C offsets at different scales and demonstrate the potential of annually resolved 14C for refining subdecadal and larger scale features for calibration, solar reconstruction, and multiproxy synchronization

Om datering av Gotlands medeltida kyrkor

About Dating the Medieval Churches of Gotland By Heikki Ranta, Joakim Hansson, Alf Lindroos, Åsa Ringbom, Jan Heinemeier, Fiona Brock & Gregory Hodgins In 2006 the project »Mortar dating of the Gotland churches« was initiated, with the aim to test how mortar dating would work in a geological area so dominated by Silurian limestone, and how the results of this method could affect the prevailing chronology of the churches. Initial testing was done on three different churches, the church of Bro in the northern part of the island, and with Hamra and Vamlingbo in the south. The result is that mortar based on Silurian limestone behaves much the same way as mortar including Åland Ordovician limestone. Thus, based on mortar dating a chronology of the church of Bro can be seen as follows: A Romanesque nave from ca AD 1040-1160, with an almost contemporary tower in the west, with an additional chancel in the east from the 13th century. In the church of Hamra, the lower part of the west tower, and possibly also the earlier part of a cruciform plan, dates from 1165-1220. Later, in 1260-80, the tower was heightened. The chancel in the east is an addition from the 14th century. In Vamlingbo, the focus was on a secondary support construction of disputed age, built against a south portal. This time the mortar was contaminated by unburned limestone, and the result of mortar dating remains inconclusive. However, fragments of wood and charcoal, incapsuled in the mortar, suggest a terminus post quem some time in the 14th century. It is most likely that the supporting wall is a medieval construction. At this initial stage it seems that the results of mortar dating in turn support earlier prevailing views on the chronology. The results also coincide with occasional dendrochronological dates and with contemporary inscriptions in the churches. It seems that mortar dating can be a helpful tool in forming an objective base for a chronology of the Gotland churches

Late Pleistocene proboscidean population dynamics in the North American Midcontinent

Understanding megafaunal population dynamics is critical to testing and refining scenarios of how extinctions occurred during the terminal Pleistocene. Large-scale, collections-based, chronological, and taphonomic analyses of midwestern Proboscidea suggest divergent population histories in mammoths and mastodons after the Last Glacial Maximum (LGM). Although extinction of both taxa occurred in the very late Bølling-Allerød (B-A) or early Younger Dryas (YD), Mammuthus is dominant during the LGM with a decreasing presence in the region until extirpation. Mammut americanum however, is absent during the LGM but becomes the dominant taxon during the subsequent B-A. Trace and physical evidence of large carnivores in post-LGM proboscidean assemblages is extremely rare, suggesting apex predators had minimal impact on mammoth and mastodon populations at this time. The ultimate mechanism(s) of extinction remain unclear; however, the wide geographic distribution of late Mammut and an increase in the frequency of multi-animal death assemblages is consistent with a large, destabilized population experiencing periodic boom-bust cycling at the end of the B-A. We suggest this pattern is due to the collapse of trophic controls on proboscidean populations prior to the LGM and a subsequent system-wide shift from top-down to bottom-up regulatory mechanisms in Proboscidea

Caballos y humanos en el Nuevo mundo: Investigaciones arqueológicas en América del Norte y perspectivas para Argentina

After their introduction by the Spaniards and other European colonizers, horses, mules, and donkeys flourished throughout the Americas, transforming the lifestyle of the original peoples. The details of this process, however, are not well known. While zooarchaeology provides us with a means to understand the adoption of the horse in the past, horse remains are often scarce in the archeological sites of early contact and historical periods. In this study we present a methodology to address these challenges, combining paleopathological analysis, radiocarbon modeling, isotopic analysis, and ZooMS. We present our work in western North America as a case study, demonstrating the early integration of the horse with the societies of native peoples over a large geographical area. The application of this approach to the early historical groups of Argentina can generate important clues about the economic and social transitions initiated by the introduction of domestic equids.Luego de su introducción por españoles y otras poblaciones europeas, los caballos, burros y mulas se expandieron por todo el continente americano, contribuyeron al proyecto colonial de poder europeo y transformaron el estilo de vida de los pueblos originarios. Los detalles de este proceso, sin embargo, no son bien conocidos. Si bien la zooarqueología nos provee de un medio para entender la adopción del caballo en escalas temporales largas, sus restos siguen siendo escasos en los sitios arqueológicos de los periodos de contacto entre comunidades originarias y eurocriollos. Se presenta una metodología para abordar estos desafíos en un caso de estudio de las Grandes Planicies (Oeste de los Estados Unidos). Los procedimientos analíticos utilizados incluyen análisis paleopatológico, modelado por radiocarbono, análisis isotópico y ZooMS. Este caso demuestra la integración temprana del caballo por parte de los pueblos originarios a lo largo de una escala geográfica amplia. La aplicación de esta aproximación a los conjuntos históricos tempranos de Argentina puede generar importantes líneas de conocimiento sobre las transiciones económicas y sociales iniciadas por la introducción de los équidos domésticos.&nbsp

Uncovering the genomic basis of an extraordinary plant invasion

Invasive species are a key driver of the global biodiversity crisis, but the drivers of invasiveness, including the role of pathogens, remain debated. We investigated the genomic basis of invasiveness in Ambrosia artemisiifolia (common ragweed), introduced to Europe in the late 19th century, by resequencing 655 ragweed genomes, including 308 herbarium specimens collected up to 190 years ago. In invasive European populations, we found selection signatures in defense genes and lower prevalence of disease-inducing plant pathogens. Together with temporal changes in population structure associated with introgression from closely related Ambrosia species, escape from specific microbial enemies likely favored the plant's remarkable success as an invasive species.Peer reviewe

Findings from an in-depth annual tree-ring radiocarbon inter-comparison

The radiocarbon calibration curve so far contains annually resolved data only for a short period of time. With accelerator mass spectrometry (AMS) matching the precision of decay counting, it is now possible to efficiently produce large datasets of annual resolution for calibration purposes using small amounts of wood. The radiocarbon inter-comparison on single-year tree-ring samples presented here is the first to investigate specifically possible offsets between AMS laboratories at high precision. The results show that AMS laboratories are capable of measuring samples of Holocene age with an accuracy and precision that is comparable or even goes beyond what is possible with decay counting, even though they require a thousand times less wood. It also shows that not all AMS laboratories always produce results that are consistent with their stated uncertainties. The long-term benefits of studies of this kind are more accurate radiocarbon measurements with, in the future, better quantified uncertainties.Additional co-authors: Douglas J Kennett, Timothy D J Knowles, Margot Kuitems, Todd E Lange, Fusa Miyake, Marie-Josée Nadeau, Toshio Nakamura, J Philip Naysmith, Jesper Olsen, Takayuki Omori, Fiona Petchey, Bente Philippsen, Christopher Bronk Ramsey, G V Ravi Prasad, Martin Seiler, John Southon, Richard Staff, Thibault Tun