22,695 research outputs found
Lithic technological responses to Late Pleistocene glacial cycling at Pinnacle Point Site 5-6, South Africa
There are multiple hypotheses for human responses to glacial cycling in the Late Pleistocene, including changes in population size, interconnectedness, and mobility. Lithic technological analysis informs us of human responses to environmental change because lithic assemblage characteristics are a reflection of raw material transport, reduction, and discard behaviors that depend on hunter-gatherer social and economic decisions. Pinnacle Point Site 5-6 (PP5-6), Western Cape, South Africa is an ideal locality for examining the influence of glacial cycling on early modern human behaviors because it preserves a long sequence spanning marine isotope stages (MIS) 5, 4, and 3 and is associated with robust records of paleoenvironmental change. The analysis presented here addresses the question, what, if any, lithic assemblage traits at PP5-6 represent changing behavioral responses to the MIS 5-4-3 interglacial-glacial cycle? It statistically evaluates changes in 93 traits with no a priori assumptions about which traits may significantly associate with MIS. In contrast to other studies that claim that there is little relationship between broad-scale patterns of climate change and lithic technology, we identified the following characteristics that are associated with MIS 4: increased use of quartz, increased evidence for outcrop sources of quartzite and silcrete, increased evidence for earlier stages of reduction in silcrete, evidence for increased flaking efficiency in all raw material types, and changes in tool types and function for silcrete. Based on these results, we suggest that foragers responded to MIS 4 glacial environmental conditions at PP5-6 with increased population or group sizes, 'place provisioning', longer and/or more intense site occupations, and decreased residential mobility. Several other traits, including silcrete frequency, do not exhibit an association with MIS. Backed pieces, once they appear in the PP5-6 record during MIS 4, persist through MIS 3. Changing paleoenvironments explain some, but not all temporal technological variability at PP5-6.Social Science and Humanities Research Council of Canada; NORAM; American-Scandinavian Foundation; Fundacao para a Ciencia e Tecnologia [SFRH/BPD/73598/2010]; IGERT [DGE 0801634]; Hyde Family Foundations; Institute of Human Origins; National Science Foundation [BCS-9912465, BCS-0130713, BCS-0524087, BCS-1138073]; John Templeton Foundation to the Institute of Human Origins at Arizona State Universit
Drones for parcel and passenger transportation: A literature review
Delivery drones and âair taxisâ are currently among the most intensely discussed emerging technologies, likely to expand mobility into the âthird dimensionâ of low-level airspace. This paper presents a systematic literature review of 111 interdisciplinary publications (2013 - 03/2019). The review systematizes the current socio-technical debate on civil drones for transportation purposes allowing for a (critical) interim assessment. To guide the review process four dimensions of analysis were defined. A total of 2581 relevant quotations were subdivided into anticipated barriers (426), potential problems (1037), proposed solutions (737) and expected benefits (381). We found that the debate is characterized by predominantly technical and regulatory problems and barriers which are considered to prevent or impede the use of drones for parcel and passengers transportation. At the same time, definite economic expectations are juxtaposed with quite complex and differentiated concerns regarding societal and environmental impacts. Scrutinizing the most prevalent transportation-related promises of traffic reduction, travel time saving and environmental relief we found that there is a strong need to provide scientific evidence for the promises linked to the use of drones for transportation. We conclude that the debate on drones for transportation needs further qualification, emphasizing societal benefits and public involvement more strongly.TU Berlin, Open-Access-Mittel - 201
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A critical knowledge pathway to low-carbon, sustainable futures: Integrated understanding of urbanization, urban areas, and carbon
Money Walks: A Human-Centric Study on the Economics of Personal Mobile Data
In the context of a myriad of mobile apps which collect personally
identifiable information (PII) and a prospective market place of personal data,
we investigate a user-centric monetary valuation of mobile PII. During a 6-week
long user study in a living lab deployment with 60 participants, we collected
their daily valuations of 4 categories of mobile PII (communication, e.g.
phonecalls made/received, applications, e.g. time spent on different apps,
location and media, photos taken) at three levels of complexity (individual
data points, aggregated statistics and processed, i.e. meaningful
interpretations of the data). In order to obtain honest valuations, we employ a
reverse second price auction mechanism. Our findings show that the most
sensitive and valued category of personal information is location. We report
statistically significant associations between actual mobile usage, personal
dispositions, and bidding behavior. Finally, we outline key implications for
the design of mobile services and future markets of personal data.Comment: 15 pages, 2 figures. To appear in ACM International Joint Conference
on Pervasive and Ubiquitous Computing (Ubicomp 2014
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2017 Texas Bays and Estuaries Meeting
Program for the 2017 Texas Bays and Estuaries Meeting held in Port Aransas, Texas, April 12-13, 2017.Coastal Bend Bays & Estuaries Program, Coastal Bend Bays Foundation, The University of Texas Marine Science Institute, Sea Grant Texas at Texas A&M University, Harte Research Institute for Gulf of Mexico Studies, and Mission Aransas National Estuarine Research Reserve.Marine Scienc
Career and Skill Formation: A Dynamic Occupational Choice Model with Multidimensional Skills
The goal of the paper is two-folds. First, I construct and estimate a dynamic structural occupational choice model at the three-digit classification level, in which different occupations involve different mix of tasks. Second, I conduct a counterfactual simulation using the estimated model, to quantify the effects of progressive income tax on post-schooling human capital investment and occupational choices. In the model, various skills are acquired through learning-by-doing, depending on the tasks of the experienced occupations. The key feature of the model is that, unlike occupation specific human capital, the acquired skills can be partly transferred to other occupations. Hence, some of low skill occupations can be viewed as âstepping stoneâ to better occupations. The structural parameters of the model are estimated using the occupational characteristics in the Dictionary of Occupational Titles and the work history in the National Longitudinal Survey of Youth 79. The results of a counterfactual simulation in the estimated model indicate that switching to a flat income tax encourages mobility to highpaying occupations and accelerates human capital accumulation. A drawback of the tax code change is an increased inequality between educational groups.Occupational Choice, Human Capital, Income Tax
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