Basketmaker II Warfare and Fending Sticks in the North American Southwest

Direct physical evidence and rock art, including head skin trophies, indicate that violence linked to warfare was prevalent among the preceramic farmers of the North American Southwest known as Basketmakers. The degree of intergroup conflict indicates that Basketmakers may have needed defense against atlatl darts. In the early 1900s archaeologists suggested that distinctive wooden artifacts served this purpose. Despite resembling Puebloan rabbit sticks, the first to report these S-shaped and flattened sticks with longitudinal facial grooves thought that hunting was not their purpose. Yet the sticks appear singularly inadequate for the task of atlatl dart defense. I evaluate the suggested function of these artifacts and their relationship to warfare in Basketmaker II society. I consider multiple lines of evidence to analyze stick function: ethnography, experiments, use-wear, bioarchaeological markers of violence, and prehistoric art. I conducted a detailed analysis of almost 500 prehistoric flat curved sticks and radiocarbon dated 63 of them. Some of the documented variation in this artifact class is geographically patterned, likely based on learning networks, but dating reveals that much of it is linked to an evident shift in tool function. The sticks become more like ethnographic rabbit sticks through time and exhibit a corresponding increase in traces of such a use. Yet, there are those with damage that seems indicative of atlatl dart defense. My experiments showed that a defender can knock aside atlatl darts from close range with these sticks. Some tribes in South America perform a similar feat in a duel-like context and Diego de Landa may have observed an analogous ritual in the 1500s among the Yucatec Maya. The fending hypothesis is most logical in a duel. Many of the analyzed prehistoric sticks come from a known Puebloan war god shrine in central New Mexico, where an informant identified one as symbol of membership in a warrior society. In addition to prowess as a man killer, war society membership in the distant past might have involved atlatl duels where dart defense with a stick displayed great skill and courage. Basketmakers may have considered S-shaped sticks as an ancient symbol of warrior status

Pre-Congestion Notification (PCN) Architecture

This document describes a general architecture for flow admission and termination based on pre-congestion information in order to protect the quality of service of established, inelastic flows within a single Diffserv domain.\u

The Relevance of Maize Pollen for Assessing the Extent of Maize Production in Chaco Canyon

Opinion is hardly unanimous, but many authors endorse the idea that Chaco Canyon is and was a marginal place for growing corn (Zea mays), a chief source of food energy for Puebloan groups in the Southwest. Poor soils with “toxic” levels of salts, inadequate and unpredictable precipitation, and a short growing season have all been identified as contributing to the agricultural marginality of the place (Benson 2011a; Bryan 1954; Force et al. 2002; Judd 1954:59–61). Benson has been the most vocal proponent of this view of late, and his research has culminated in the conclusion that “the San Juan Basin, including Chaco Canyon, appears to be the least promising area for dryland farming; that is, it is too dry and its soils are Npoor, saline and too basic (high pH values) for the production of maize” (Benson 2011a:49–50; Benson 2011b). The Chaco Project’s experimental maize fields in the late 1970s seem to bear out this statement: “Chaco, under modern conditions, is indeed marginal as a corn growing environment” (Toll et al. 1985:124). If Chaco Canyon is as marginal for farming as many claim, then the cultural achievements of the Puebloans that lived there are all the more remarkable, and this marginality has figured prominently in many interpretations about how and why Chaco Canyon developed as it did (Judge 1979, 1989; Schelberg 1981, 1982; Sebastian 1983, 1991, 1992; Vivian 1984, 1990). Chacoans had to import not only beams for building, pottery for cooking and storage, and stone for flaked tools but also even the staff of life—corn. And when you add in such exotics as turquoise, parrots, copper bells, and cacao, the potential “trade” deficit looms large. If Chaco Canyon did not provide even enough food for basic sustenance, what was it that made the place so special in the first place? More importantly, what literally fueled the obvious cultural fluorescence of Chaco Canyon and ts massive labor-intensive construction projects? Wills and Dorshow (2012:138) observe that “the popular perspective that Chaco was mysterious or enigmatic is largely a response to this view of the canyon as agriculturally marginal.” Yet, how do we know what the agricultural potential of the canyon was during the Bonito phase (ca. A.D. 850–1140) or that Chacoans could not provide for themselves? Perhaps the pendulum has swung too far toward a pessimistic assessment of the maize farming in and around the canyon. Certainly, Navajo farmers with considerable traditional knowledge and a real stake in the outcome successfully grew corn within Chaco Canyon (Judd 1954:52–59), and in 1898, George Pepper photographed Navajo fields on the floodplain of Chaco Canyon proper that produced a bountiful corn harvest ( Figure 1a). Since photo documentation is not anecdotal, it seems a sufficient counter to assertions that farming of the Chaco floodplain was impossible because of high salinity. Judd’s records of Navajo maize harvests evidently come from a time of more favorable precipitation and growingseason length, but this, too, could have characterized much of the Bonito phase. Figure 1b shows another Navajo field on the main floodplain at harvest time. Navajo farmers clearly experienced agricultural risk (Huntington 1914:81), but evidently the canyon proved a sufficient attraction to entice early settlement by them (Brugge 1986), perhaps precisely because of its productive potential. Farming potential was likely the prime motivation for initial Basketmaker settlement, a time when supplemental extra-local sources of maize were improbable. Since everything is relative, Chaco Canyon may have seemed like a small Eden in the context of the vast “dreary wastes” (Huntington 1914:81) of the San Juan Basin at large

The topological classification of one-dimensional symmetric quantum walks

We give a topological classification of quantum walks on an infinite 1D lattice, which obey one of the discrete symmetry groups of the tenfold way, have a gap around some eigenvalues at symmetry protected points, and satisfy a mild locality condition. No translation invariance is assumed. The classification is parameterized by three indices, taking values in a group, which is either trivial, the group of integers, or the group of integers modulo 2, depending on the type of symmetry. The classification is complete in the sense that two walks have the same indices if and only if they can be connected by a norm continuous path along which all the mentioned properties remain valid. Of the three indices, two are related to the asymptotic behaviour far to the right and far to the left, respectively. These are also stable under compact perturbations. The third index is sensitive to those compact perturbations which cannot be contracted to a trivial one. The results apply to the Hamiltonian case as well. In this case all compact perturbations can be contracted, so the third index is not defined. Our classification extends the one known in the translation invariant case, where the asymptotic right and left indices add up to zero, and the third one vanishes, leaving effectively only one independent index. When two translationally invariant bulks with distinct indices are joined, the left and right asymptotic indices of the joined walk are thereby fixed, and there must be eigenvalues at $1$ or $-1$ (bulk-boundary correspondence). Their location is governed by the third index. We also discuss how the theory applies to finite lattices, with suitable homogeneity assumptions.Comment: 36 pages, 7 figure

Chiral Floquet systems and quantum walks at half period

We classify periodically driven quantum systems on a one-dimensional lattice, where the driving process is local and subject to a chiral symmetry condition. The analysis is in terms of the unitary operator at a half-period and also covers systems in which this operator is implemented directly, and does not necessarily arise from a continuous time evolution. The full-period evolution operator is called a quantum walk, and starting the period at half time, which is called choosing another timeframe, leads to a second quantum walk. We assume that these walks have gaps at the spectral points $\pm1$, up to at most finite dimensional eigenspaces. Walks with these gap properties have been completely classified by triples of integer indices (arXiv:1611.04439). These indices, taken for both timeframes, thus become classifying for half-step operators. In addition a further index quantity is required to classify the half step operators, which decides whether a continuous local driving process exists. In total, this amounts to a classification by five independent indices. We show how to compute these as Fredholm indices of certain chiral block operators, show the completeness of the classification, and clarify the relations to the two sets of walk indices. Within this theory we prove bulk-edge correspondence, where second timeframe allows to distinguish between symmetry protected edge states at $+1$ and $-1$ which is not possible with only one timeframe. We thus resolve an apparent discrepancy between our above mentioned index classification for walks, and indices defined (arXiv:1208.2143). The discrepancy turns out to be one of different definitions of the term `quantum walk'.Comment: 25 pages, 2 figure

Highly sensitive and label-free digital detection of whole cell E. coli with interferometric reflectance imaging

Bacterial infectious diseases are a major threat to human health. Timely and sensitive pathogenic bacteria detection is crucial in identifying the bacterial contaminations and preventing the spread of infectious diseases. Due to limitations of conventional bacteria detection techniques there have been concerted research efforts towards development of new biosensors. Biosensors offering label free, whole bacteria detection are highly desirable over those relying on label based or pathogenic molecular components detection. The major advantage is eliminating the additional time and cost required for labeling or extracting the desired bacterial components. Here, we demonstrate rapid, sensitive and label free E. coli detection utilizing interferometric reflectance imaging enhancement allowing for visualizing individual pathogens captured on the surface. Enabled by our ability to count individual bacteria on a large sensor surface, we demonstrate a limit of detection of 2.2 CFU/ml from a buffer solution with no sample preparation. To the best of our knowledge, this high level of sensitivity for whole E. coli detection is unprecedented in label free biosensing. The specificity of our biosensor is validated by comparing the response to target bacteria E. coli and non target bacteria S. aureus, K. pneumonia and P. aeruginosa. The biosensor performance in tap water also proves that its detection capability is unaffected by the sample complexity. Furthermore, our sensor platform provides high optical magnification imaging and thus validation of recorded detection events as the target bacteria based on morphological characterization. Therefore, our sensitive and label free detection method offers new perspectives for direct bacterial detection in real matrices and clinical samples.First author draf

A key role for stimulus-specific updating of the sensory cortices in the learning of stimulus-reward associations

Successful adaptive behavior requires the learning of associations between stimulus-specific choices and rewarding outcomes. Most research on the mechanisms underlying such processes has focused on subcortical reward-processing regions, in conjunction with frontal circuits. Given the extensive stimulus-specific coding in the sensory cortices, we hypothesized they would play a key role in the learning of stimulus-specific reward associations. We recorded electrical brain activity (EEG) during a learning-based, decision-making, gambling task where, on each trial, participants chose between a face and a house and then received feedback (gain or loss). Within each 20-trial set, either faces or houses were more likely to predict a gain. Results showed that early feedback processing (~200-1200ms) was independent of the choice made. In contrast, later feedback processing (~1400-1800ms) was stimulus-specific, reflected by decreased alpha power (reflecting increased cortical activity) over face-selective regions. For winning-versus-losing after a face choice, but not after a house choice. Finally, as the reward association was learned in a set, there was increasingly stronger attentional bias towards the more likely winning stimulus, reflected by increasing attentional-orienting-related brain activity and increasing likelihood of choosing that stimulus. These results delineate the processes underlying the updating of stimulus-reward associations during feedback-guided learning, which then guides future attentional allocation and decision making