614 research outputs found

    Reconsidering “Tokens”: The Neolithic origins of accounting or multifunctional, utilitarian tools?

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    The origin of record keeping is a key question in the development of social complexity and specialized economies, representing the first step towards the emergence of written communication. Yet the precursors of the world's earliest writing and its initial stages of development remain little understood. Small, geometric clay objects (‘tokens’) appear in the tenth millennium cal. bc, the start of the Neolithic in West Asia, prevailing into the first millennium. It is largely assumed that from their inception clay objects played a crucial role in record keeping, directly evolving into the world's earliest known writing. Utilizing new and previously unpublished Neolithic data comprising almost individually studied 3000 objects, accompanied by information from 56 further Neolithic sites, this article investigates the meaning of Neolithic ‘tokens’. Analysis proves the basis of their predominant interpretation to be incorrect; clay objects appear earlier than previously recognized and are not a necessary component of Neolithic agro-pastoral villages. ‘Tokens’ were multi-functional artefacts; even within a single site clay objects performed multiple roles. Though likely used in simple counting activities, this was not limited to the accounting of agricultural produce. Nor was counting the sole function of clay objects in the Neolithic. Clay objects were not created to administer agricultural produce and there is no evidence to suggest that in the Neolithic they formed part of a unified symbolic system.Middle Eastern Studie

    Large clay balls at Çatalhöyük East

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    Middle Eastern Studie

    Nonlinear porous medium flow with fractional potential pressure

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    We study a porous medium equation, with nonlocal diffusion effects given by an inverse fractional Laplacian operator. We pose the problem in n-dimensional space for all t>0 with bounded and compactly supported initial data, and prove existence of a weak and bounded solution that propagates with finite speed, a property that is nor shared by other fractional diffusion models.Comment: 32 pages, Late

    Association between hourly wages and dietary intake after the first phase of implementation of the Minneapolis minimum wage ordinance

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    Objective: In 2018, Minneapolis began phased implementation of an ordinance to increase the local minimum wage to 15/h. We sought to determine whether the first phase of implementation was associated with changes in frequency of consumption of fruits and vegetables (F&V), whole-grain-rich foods, and foods high in added sugars among low-wage workers. Design: Natural experiment. Setting: The Wages Study is a prospective cohort study of 974 low-wage workers followed throughout the phased implementation of the ordinance (2018-2022). We used difference-in-difference analysis to compare outcomes among workers in Minneapolis, Minnesota, to those in a comparison city (Raleigh, North Carolina). We assessed wages using participants' pay stubs and dietary intake using the National Cancer Institute Dietary Screener Questionnaire. Participants: Analyses use the first two waves of Wages data (2018 (baseline), 2019) and includes 267 and 336 low-wage workers in Minneapolis and Raleigh, respectively. Results: After the first phase of implementation, wages increased in both cities, but the increase was 0·84 greater in Minneapolis (P = 0·02). However, the first phase of the policy's implementation was not associated with changes in daily frequency of consumption of F&V (IRR = 1·03, 95 % CI: 0·86, 1·24, P = 0·73), whole-grain-rich foods (IRR = 1·23, 95 % CI: 0·89, 1·70, P = 0·20), or foods high in added sugars (IRR = 1·13, 95 % CI: 0·86, 1·47, P = 0·38) among workers in Minneapolis compared to Raleigh. Conclusions: The first phase of implementation of the Minneapolis minimum wage policy was associated with increased wages, but not with changes in dietary intake. Future research should examine whether full implementation is associated dietary changes

    Direct monitoring of pulmonary disease treatment biomarkers using plasmonic gold nanorods with diffusion-sensitive OCT

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    The solid concentration of pulmonary mucus (wt%) is critical to respiratory health. In patients with respiratory disease, such as Cystic Fibrosis (CF) and Chronic Obstructive Pulmonary Disorder (COPD), mucus hydration is impaired, resulting in high wt%. Mucus with high wt% is a hallmark of pulmonary disease that leads to obstructed airways, inflammation, and infection. Methods to measure mucus hydration in situ and in real-time are needed for drug development and personalized therapy. We employed plasmonic gold nanorod (GNR) biosensors that intermittently collide with macromolecules comprising the mucus mesh as they self-diffuse, such that GNR translational diffusion (DT) is sensitive to wt%. GNRs are attractive candidates for bioprobes due to their anisotropic optical scattering that makes them easily distinguishable from native tissue using polarization-sensitive OCT. Using principles of heterodyne dynamic light scattering, we developed diffusion-sensitive optical coherence tomography (DS-OCT) to spatially-resolve changing DT in real-time. DS-OCT enables, for the first time, direct monitoring of changes in nanoparticle diffusion rates that are sensitive to nanoporosity with spatial and temporal resolutions of 4.7 μm and 0.2 s. DS-OCT therefore enables us to measure spatially-resolved changes in mucus wt% over time. In this study, we demonstrate the applicability of DS-OCT on well-differentiated primary human bronchial epithelial cells during a clinical mucus-hydrating therapy, hypertonic saline treatment (HST), to reveal, for the first time, mucus mixing, cellular secretions, and mucus hydration on the micrometer scale that translate to long-term therapeutic effects

    The luminosities of protostars in the spitzer c2d and gould belt legacy clouds

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    Journal ArticlePublished version available online at the Astronomical Journal, Volume 145, Number 4, Article 94; doi: doi: 10.1088/0004-6256/145/4/94Motivated by the long-standing "luminosity problem" in low-mass star formation whereby protostars are underluminous compared to theoretical expectations, we identify 230 protostars in 18 molecular clouds observed by two Spitzer Space Telescope Legacy surveys of nearby star-forming regions. We compile complete spectral energy distributions, calculate L bol for each source, and study the protostellar luminosity distribution. This distribution extends over three orders of magnitude, from 0.01 L ȯ to 69 L ȯ, and has a mean and median of 4.3 L ȯ and 1.3 L ȯ, respectively. The distributions are very similar for Class 0 and Class I sources except for an excess of low luminosity (L bol ≲ 0.5 L) Class I sources compared to Class 0. 100 out of the 230 protostars (43%) lack any available data in the far-infrared and submillimeter (70 μm <λ < 850 μm) and have L bol underestimated by factors of 2.5 on average, and up to factors of 8-10 in extreme cases. Correcting these underestimates for each source individually once additional data becomes available will likely increase both the mean and median of the sample by 35%-40%. We discuss and compare our results to several recent theoretical studies of protostellar luminosities and show that our new results do not invalidate the conclusions of any of these studies. As these studies demonstrate that there is more than one plausible accretion scenario that can match observations, future attention is clearly needed. The better statistics provided by our increased data set should aid such future work. © 2013. The American Astronomical Society. All rights reserved..National Science FoundationNational Aeronautics and Space AdministrationJet Propulsion Laboratory, California Institute of Technolog
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