964 research outputs found
Interaction on the Frontier of the 16\u3csup\u3eth\u3c/sup\u3e-17\u3csup\u3eth\u3c/sup\u3e Century World Economy: Late Fort Ancient Hide Production and Exchange at the Hardin Site, Greenup County, Kentucky
This study assesses the organization and intensity of hide processing from sequential occupations at the Late Fort Ancient (A.D. 1400-1680) Hardin Site located in the central Ohio Valley. Historical and archaeological sources were drawn on to develop expectations for production intensification: 1) an increase in production tool quantity, 2) an increase in production debris quantity, and 3) an increase in tool utilization intensity. Many Native groups situated on the periphery of early European colonies intensified hide production to meet demand generated by an emerging global trade in hides. As this economic activity intensified in the 16th and 17th centuries it incorporated and ever greater network of native communities. By documenting production intensification at the Hardin Site, this study evaluates the degree to which global markets incorporated regions beyond the colonial periphery before A.D. 1680. This study also examines the social dimensions of economic activity by asking who processed hides, who may have benefited from the products of this labor, and whether or not either of these were influenced by participation in the tumultuous interaction sphere of the eastern North American Contact Period
Spectral imaging of thermal damage induced during microwave ablation in the liver
Induction of thermal damage to tissue through delivery of microwave energy is
frequently applied in surgery to destroy diseased tissue such as cancer cells.
Minimization of unwanted harm to healthy tissue is still achieved subjectively,
and the surgeon has few tools at their disposal to monitor the spread of the
induced damage. This work describes the use of optical methods to monitor the
time course of changes to the tissue during delivery of microwave energy in the
porcine liver. Multispectral imaging and diffuse reflectance spectroscopy are
used to monitor temporal changes in optical properties in parallel with thermal
imaging. The results demonstrate the ability to monitor the spatial extent of
thermal damage on a whole organ, including possible secondary effects due to
vascular damage. Future applications of this type of imaging may see the
multispectral data used as a feedback mechanism to avoid collateral damage to
critical healthy structures and to potentially verify sufficient application of
energy to the diseased tissue.Comment: 4pg,6fig. Copyright 2018 IEEE. Personal use of this material is
permitted. Permission from IEEE must be obtained for all other uses, in any
current or future media, including reprinting/republishing this material for
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component of this work in other work
Hippocampal Replay of Extended Experience
During pauses in exploration, ensembles of place cells in the rat hippocampus re-express firing sequences corresponding to recent spatial experience. Such āreplayā co-occurs with ripple events: short-lasting (ā¼50ā120 ms), high-frequency (ā¼200 Hz) oscillations that are associated with increased hippocampal-cortical communication. In previous studies, rats exploring small environments showed replay anchored to the rat's current location and compressed in time into a single ripple event. Here, we show, using a neural decoding approach, that firing sequences corresponding to long runs through a large environment are replayed with high fidelity and that such replay can begin at remote locations on the track. Extended replay proceeds at a characteristic virtual speed of ā¼8 m/s and remains coherent across trains of ripple events. These results suggest that extended replay is composed of chains of shorter subsequences, which may reflect a strategy for the storage and flexible expression of memories of prolonged experience.Massachusetts Institute of Technology. Department of Brain and Cognitive Science (Singleton Fellowship)National Institutes of Health (U.S.) (grant MH061976
Recommendations for Improving the MIK Website and Overall Marketing Strategy
Museer I Kobenhavn (MIK) is an organization that represents over seventy diverse museums in Copenhagen and the surrounding area. This report presents a proposed plan to aid MIK to better attain their mission of promoting these museums. By identifying and investigating member museums\u27, museum visitors\u27, and website users\u27 needs, we made recommendations to improve their website and overall marketing strategy to reach a broader audience
EST analysis of gene expression in early cleavage-stage sea urchin embryos
A set of 956 expressed sequence tags derived from 7-hour (mid-cleavage) sea urchin embryos was analyzed to assess biosynthetic functions and to illuminate the structure of the message population at this stage. About a quarter of the expressed sequence tags represented repetitive sequence transcripts typical of early embryos, or ribosomal and mitochondrial RNAs, while a majority of the remainder contained significant open reading frames. A total of 232 sequences, including 153 different proteins, produced significant matches when compared against GenBank. The majority of these identified sequences represented āhousekeepingā proteins, i.e., cytoskeletal proteins, metabolic enzymes, transporters and proteins involved in cell division. The most interesting finds were components of signaling systems and transcription factors not previously reported in early sea urchin embryos, including components of Notch and TGF signal transduction pathways. As expected from earlier kinetic analyses of the embryo mRNA populations, no very prevalent protein-coding species were encountered; the most highly represented such sequences were cDNAs encoding cyclins A and B. The frequency of occurrence of all sequences within the database was used to construct a sequence prevalence distribution. The result, confirming earlier mRNA population analyses, indicated that the poly(A) RNA of the early embryo consists mainly of a very complex set of low-copy-number transcripts
Large scale simulation of labeled intraoperative scenes in unity
PURPOSE: The use of synthetic or simulated data has the potential to greatly improve the availability and volume of training data for image guided surgery and other medical applications, where access to real-life training data is limited. METHODS: By using the Unity game engine, complex intraoperative scenes can be simulated. The Unity Perception package allows for randomisation of paremeters within the scene, and automatic labelling, to make simulating large data sets a trivial operation. In this work, the approach has been prototyped for liver segmentation from laparoscopic video images. 50,000 simulated images were used to train a U-Net, without the need for any manual labelling. The use of simulated data was compared against a model trained with 950 manually labelled laparoscopic images. RESULTS: When evaluated on data from 10 separate patients, synthetic data outperformed real data in 4 out of 10 cases. Average DICE scores across the 10 cases were 0.59 (synthetic data), 0.64 (real data) and 0.75 (both synthetic and real data). CONCLUSION: Synthetic data generated using this method is able to make valid inferences on real data, with average performance slightly below models trained on real data. The use of the simulated data for pre-training boosts model performance, when compared with training on real data only
Surfactant-free poly(lactide-co-glycolide) honeycomb films for tissue engineering: relating solvent, monomer ratio and humidity to scaffold structure
International audienceOne-step surfactant-free, water-droplet templating has been developed as a fabrication method for a poly(lactide-co-glycolide) (PLGA) film that can be used as a model to investigate the relationship between solvent, monomer ratio, polymer concentration and humidity on its structure. The resulting material is a honeycomb-structured film. Formation of this structure was highly sensitive to solvent, monomer ratio, polymer concentration and humidity. Surfactant-free, water-droplet templating thus allows investigation of fabrication parameters and that PLGA monomer ratio selection is important for scaffold structure but not for MG63 cell attachment and proliferation
Polarimetric imaging for air accident investigation
We report a trial wherein a simple 4 CCD visible-band Polarimetric Imaging (PI) camera was fielded against aircraft
debris distributed across an arid terrain, a littoral region and a small number of maritime debris targets
A debris field realistically simulating an aircrash and a debris grid of aircraft remains were observed from an air platform
flying in dry and sunny conditions.
We report PI utility in support of air accident investigation by an enhanced ability to successfully locate small targets
within the scene via the use of colour enhanced and decorrelated intensity PI products. Our results indicate that handheld
PI capability may represent an effective low cost, upgrade and augmentation option for existing and future imaging
systems that would support air accident investigators and assist in the cueing of more sophisticated assets and/or analyst
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