2,422 research outputs found
Citizen Science in Archaeology
Citizen science, as a process of volunteer participation through crowdsourcing, facilitates the creation of mass data sets needed to address subtle and large-scale patterns in complex phenomena. Citizen science efforts in other field disciplines such as biology, geography, and astronomy indicate how new web-based interfaces can enhance and expand upon archaeologists' existing platforms of volunteer engagement such as field schools, community archaeology, site stewardship, and professional-avocational partnerships. Archaeological research can benefit from the citizen science paradigm in four ways: fieldwork that makes use of widely available technologies such as mobile applications for photography and data upload; searches of large satellite image collections for site identification and monitoring; crowdfunding; and crowdsourced computer entry of heritage data
How Ancient Agriculturalists Managed Yield Fluctuations through Crop Selection and Reliance on Wild Plants: An Example from Central India
The use of "average" yields to formulate models of premodern agriculture obscures the dynamic components of agricultural decision-making. Using colonial documents and archaeological data from the Deccan region of central India, this paper illustrates the complexities of how ancient peoples initigated fluctuations in agricultural yields. Nineteenth-century documents show striking differences in yields from year to year and illustrate the way in which people compensated for those fluctuations by using wild foods and cultivating alternate crops that were less palatable but more reliable. Archaeobotanical, archaeological, and textual data from the Chalcolithic to the Early Historic periods (c. 1500 B.C. to 300 A.D.) indicate similar adaptive strategies, in which the early inhabitants of the region managed resources at the household level to provide subsistence security, as well as the steady provision of a tradable surplus
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New data on carbon isotopic compositions of some ureilites
We have collected new C data from high resolution stepped combustion analyses of 5 ureilites to better constrain their relationships with O and mineralogical/petrographic groupings. This may help the future development of petrogenetic models
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An integrated mineralogical, petrographic, light stable isotope and noble gas investigation of Sahara 99201 ureilite
New ureilite Sahara 99201 has been investigated to determine mineralogy, petrography, light stable isotopes and noble gases. The sample is a typical olivine pigeonite ureilite (Fo 78, Wo 10, En 72). C, N, O and Ar are consistent with other ureilites
Characterization of a Double Mesospheric Bore Over Europe
Observations of a pair of mesospheric bore disturbances that propagated through the nighttime mesosphere over Europe are presented. The observations were made at the Padua Observatory, Asiago (45.9\ub0N, 11.5\ub0E), by the Boston University all-sky imager on 11 March 2013. The bores appeared over the northwest horizon, approximately 30 min apart, and propagated toward the southeast. Using additional satellite and radar data, we present evidence indicating the bores originated in the mesosphere from a single, larger-scale mesospheric disturbance propagating through the mesopause region. Furthermore, the large-scale mesospheric disturbance appeared to be associated with an intense weather disturbance that moved southeastward over the United Kingdom and western Europe during 10 and 11 March
FreeSurfer vs. Manual Tracing: Distinguishing Stable from Cognitively Declining Elders Using Prospectively Measured Hippocampal Volume
Objective: Alzheimer’s disease (AD) pathology is thought to begin years before symptom onset. Hippocampal volume is sensitive to age-related cognitive decline and conversion from MCI to AD. Measurement of hippocampal volumes has used either automated methods such as FreeSurfer (FS) or manual tracing (MT). We compared the ability of FS and MT in detecting baseline volume differences in cognitively intact older individuals who subsequently showed significant cognitive decline.
Participants and Methods: Seventy-five cognitively intact elders underwent baseline and 18-month follow-up structural MRI scan and neuropsychological testing. Participants were classified as Declining (n=27) or Stable (n=48) based on the baseline to 18-month changes on a listlearning task and a measure of general cognitive functioning. A 2 (left, right) x 2 (anterior, posterior) x 2 (Declining, Stable) repeated measures ANOVA was conducted for both the MT and FS hippocampal volumes derived at baseline.
Results: MT identified significantly smaller left and right hippocampal volumes and smaller anterior than posterior hippocampal volumes in Declining compared to Stable subjects. In contrast, no group differences in hippocampal volumes were observed using FS. Notably, MT included more subiculum and entorhinal cortex, while FS included more of the amygdala and the CA region of the hippocampus.
Conclusions: MT was superior to FS for detecting prospective volumetric differences associated with cognitive decline in cognitively intact older participants. MT afforded more unique coverage of the anterior hippocampus than FS. The differences in regional coverage of the mesial temporal lobe between MT and FS may account for the different findings in discriminating Stable and Declining groups
Prediction of Longitudinal White Matter Change in Healthy Elderly Individuals
Diffusion Tensor Imaging (DTI) studies have shown that significant alteration in white matter (WM) integrity differentiates healthy older adults from persons with Mild Cognitive Impairment (MCI) and Alzheimer\u27s disease (AD). Most studies, however, have been cross-sectional and have not related longitudinal DTI changes to cognitive change. Here we report changes in WM integrity and cognition in healthy older adults over an 18-month interval. Sixty-seven cognitively intact elders underwent neuropsychological testing and DTI at baseline to follow-up on the Rey Auditory Verbal Learning Test (recall sum across trials 1-5, delayed recall) and Mattis Dementia Rating Scale-2. Declining participants (N=21) showed a minimum of 1 SD reduction on at least one cognitive measure, while Stable participants (N=46) showed comparable scores at each time point. WM regions-of-interest were derived from Freesurfer. Hierarchical linear regression was used to predict fractional anisotropy (FA) change in regions frequently identified in DTI studies of MCI and AD including transentorhinal cortex, temporal lobe, and posterior cingulate. Groups did not differ at baseline in age, cognition, FA, or WM volume. After controlling for age and baseline FA, cognitive status (Declining, Stable) predicted the baseline to 18-month reduction in FA in the right hippocampal gyrus (p=.004) and left fusi-form gyrus (p=.01) with a trend in the left middle temporal gyrus (p=.06). Future research should examine WM changes in other brain regions and determine whether DTI diffusivity measures are related to cognitive decline
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