An Art-Historical Paradigm for Investigating Native American Pictographs of the Lower Pecos Region, Texas

In the shadows of deep canyons in Southwest Texas and Northern Mexico, where the Pecos, Devils, and Rio Grande flow, are thousands of paintings on the walls of hundreds of rockshelters and overhangs. Archaeologists term such works pictographic rock art. These particular pictographs were created over many centuries by Native American groups known collectively today as the Lower Pecos Region cultures

The Zero Discounting and Maximin Optimal Paths in a Simple Model of Global Warming

Following Stollery (1998), we extend the Solow-- Dasgupta--Heal model to analyze the effects of global warming The rise of temperature is caused by the use of fossil resources so that the temperature level can be linked to the remaining stock of these resources. The rise of temperature affects both productivity and utility. We characterize optimal solutions for the maximin and zero-discounting cases and present closed form solutions for the case where the production and utility functions are Cobb-Douglas, and the temperature level is an exponential function of the remaining stock of resources. We show that a greater weight of temperature in intratemporal preferences or a larger intertemporal elasticity of substitution both lead to postpone resource use.Global warming;Zero discounting;maximin

Gesture Typing on Virtual Tabletop: Effect of Input Dimensions on Performance

The association of tabletop interaction with gesture typing presents interaction potential for situationally or physically impaired users. In this work, we use depth cameras to create touch surfaces on regular tabletops. We describe our prototype system and report on a supervised learning approach to fingertips touch classification. We follow with a gesture typing study that compares our system with a control tablet scenario and explore the influence of input size and aspect ratio of the virtual surface on the text input performance. We show that novice users perform with the same error rate at half the input rate with our system as compared to the control condition, that an input size between A5 and A4 present the best tradeoff between performance and user preference and that users' indirect tracking ability seems to be the overall performance limiting factor

The Zero discounting and maximin optimal paths in a simple model of global warming

Following Stollery [1998], we extend the Solow, Dasgupta-Heal model to analyze the effects of global warning. The rise of temperature is caused by the use of fossil resources so that the temperature level can be linked to the remaining stock of these resources. The rise of temperature affects both productivity and utility. We characterize optimal solutions for the maximin and zero-discounting cases and present closed form solutions for the case where the production function and utility function are Cobb-Douglas, and the temperature level is an exponential function of the remaining stock of resources. We show that a greater weight of temperature in the preferences or a larger intertemporal elasticity of substitution both lead to postpone resource use.Maximin ; zero discounting ; global warming

Product Quality and Worker Quality

We study the relation between product quality and worker quality using an economic model that, under certain conditions, provides a direct link between product price, product quality and work force quality. Our measures of product quality are the evolution in the detailed product price relative to its product group and the level of the product price relative to this group. Our worker quality measures are the firm's average person effect and personal characteristics effect from individual wage rates. We find a very weak, generally positive, relation between worker quality and product quality using detailed firm-level data from the French Producer Price Index surveys.

Carbon taxes, path dependency and directed technical change: evidence from the auto industry

Can directed technical change be used to combat climate change? We construct new firm-level panel data on auto industry innovation distinguishing between “dirty” (internal combustion engine) and “clean” (e.g. electric and hybrid) patents across 80 countries over several decades. We show that firms tend to innovate relatively more in clean technologies when they face higher tax-inclusive fuel prices. Furthermore, there is path dependence in the type of innovation both from aggregate spillovers and from the firm's own innovation history. Using our model we simulate the increases in carbon taxes needed to allow clean to overtake dirty technologies

Inheritance-Based Diversity Measures for Explicit Convergence Control in Evolutionary Algorithms

Diversity is an important factor in evolutionary algorithms to prevent premature convergence towards a single local optimum. In order to maintain diversity throughout the process of evolution, various means exist in literature. We analyze approaches to diversity that (a) have an explicit and quantifiable influence on fitness at the individual level and (b) require no (or very little) additional domain knowledge such as domain-specific distance functions. We also introduce the concept of genealogical diversity in a broader study. We show that employing these approaches can help evolutionary algorithms for global optimization in many cases.Comment: GECCO '18: Genetic and Evolutionary Computation Conference, 2018, Kyoto, Japa

[Review of] Brian W. Dippie. George Catlin and his Contemporaries: The Politics of Patronage

Although Americans in the 1990\u27s often argue whether an artist\u27s or researcher\u27s work merits public funding, many agree that we should fund both the arts and scientific inquiry in nearly all their diverse forms. But the basic question of patronage remains. Federal and private funding of arts and science-related work were much in question over a hundred years ago, when the artist George Catlin requested that the United States government purchase his American Indian collection

Stable and Clumped Isotope Characterization of Authigenic Carbonates in Methane Cold Seep Environments

Cold seep environments are characterized by methane-rich fluid migration and discharge at the seafloor. These environments are also intimately linked to microbial communities, which oxidize methane anaerobically, increase alkalinity and promote authigenic carbonate precipitation. We have analyzed a suite of methane-derived authigenic carbonate (MDAC) crusts from the North and Barents Sea using stable and clumped isotopes (δ¹³C, δ¹⁸O, δ⁴⁴Ca, and Δ₄₇) to characterize the sources of fluids as well as the environment of carbonate authigenesis. We additionally assess the potential of MDACs as a Δ₄₇-based paleotemperature archive. The MDACs occur as three main textural-mineralogic types: micritic Mg-calcite cements, micritic aragonite cements and cavity filling aragonite cements. We find that micritic Mg-calcite cements have low δ¹³C_(VPDB) values (−30 to −47‰), high δ⁴⁴Ca_(SW) values (−0.4 to −0.8‰), and Δ₄₇-temperatures (0–6 °C) consistent with shallow sub-seafloor precipitation in isotopic equilibrium. Micritic aragonite cements and cavity filling aragonite cements both have a wider range in δ¹³C_(VPDB) values (−18 to −58‰), lower δ⁴⁴Ca_(SW) values (−0.8 to −1.6‰) and a larger range in Δ₄₇-based apparent temperatures (–2 – 25 °C) with samples displaying equilibrium and disequilibrium clumped isotope values. The range in apparent temperatures as well as δ⁴⁴Ca_(SW) values seen in the aragonite MDACs suggest two kinetic processes: a kinetic isotope effect (KIE) due to the incomplete equilibration of carbon and oxygen isotopes among DIC species from the different sources of DIC (i.e., seawater, methane-sourced DIC and DIC residual to CO₂ degassing or diffusion) and a KIE due to a fast, irreversible precipitation affecting the cations, particularly Ca, bound to carbonate mineral. Our results improve the understanding of kinetic effects on clumped isotope temperatures in MDACs and demonstrate how the multi-isotopic approach combined with textural-mineralogic criteria can be used to identify MDACs for accurate paleotemperature reconstructions