3,208 research outputs found

    Hands Are Hard: Unlearning How We Talk About Machine Learning in the Arts

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    Evoking the spirits of Fluxus scores and art education drawing books from the early 1900s, this instructional art object guides the reader through a series of poetic prompts, designed to investigate the phenomenon of “bad hands” created by generative artificial intelligence. By now everyone has seen the AI-generated images of hands from the uncanny valley. A body of discourse has emerged to discuss “bad hands” in generated images, including their usefulness as a media literacy tool for identifying synthetic images and as evidence of the continued necessity for humans’ artistic abilities. However, these applications may be short-lived as it is only a matter of time before these systems are capable of rendering human hands that are indistinguishable from our own. Before these “bad hands” disappear from view, they might lend artists/educators a hand – a chance to unlearn how we think about machine learning. By learning to create intentional “bad hands,” these creative prompts not only reveal the ways these systems have defined “bad” and “hands,” but also equip us to interrogate the definition of human hiding inside of its mysterious black box

    Structure and Composition of Old-Growth and Unmanaged Second-Growth Riparian Forests at Redwood National Park, USA

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    Restoration of second-growth riparian stands has become an important issue for managers of redwood (Sequoia sempervirens [D. Don] Endl.) forest reserves. Identifying differences between old-growth and second-growth forest vegetation is a necessary step in evaluating restoration needs and targets. The objective of this study was to characterize and contrast vegetation structure and composition in old-growth and unmanaged second-growth riparian forests in adjacent, geomorphologically similar watersheds at Redwood National Park. In the old-growth, redwood was the dominant overstory species in terms of stem density, basal area, and importance values. Second-growth was dominated by red alder (Alnus rubra Bong.), Douglas-fir (Pseudotsuga menziesii [Mirbel] Franco), and redwood. Understory species were similar in both forests, with several key differences: Oxalis oregana Nutt. and Trillium ovatum Pursh had greater importance values in the old-growth, and Vaccinium parvifolium Sm., Dryopteris spp. and sedges Carex spp. had greater importance values in the second-growth. Notable differences in structure and composition suggest that restoration practices such as thinning could expedite the acquisition of old-growth characteristics in second-growth riparian forests

    Challenges in imaging and predictive modeling of rhizosphere processes

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    Background Plant-soil interaction is central to human food production and ecosystem function. Thus, it is essential to not only understand, but also to develop predictive mathematical models which can be used to assess how climate and soil management practices will affect these interactions. Scope In this paper we review the current developments in structural and chemical imaging of rhizosphere processes within the context of multiscale mathematical image based modeling. We outline areas that need more research and areas which would benefit from more detailed understanding. Conclusions We conclude that the combination of structural and chemical imaging with modeling is an incredibly powerful tool which is fundamental for understanding how plant roots interact with soil. We emphasize the need for more researchers to be attracted to this area that is so fertile for future discoveries. Finally, model building must go hand in hand with experiments. In particular, there is a real need to integrate rhizosphere structural and chemical imaging with modeling for better understanding of the rhizosphere processes leading to models which explicitly account for pore scale processes

    Hindered Rotation in Methyl Alcohol with Note on Ethyl Alcohol

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    The potential barrier to the internal rotation in methyl alcohol is recalculated from the entropy with the aid of new molecular dimensions generously provided by Burkhard and Dennison. The barrier calculation is examined for temperature dependence and checked for reliability by recalculation with the Clapeyron equation substituted for parts of the data. The result is 1600±700 cal./mole, which includes the new spectroscopic barrier of Burkhard and Dennison at 326 cm−1. Within the range covered by the result, a residual entropy up to 0.50 cal./mole deg. is possible, and the retention of 0.46 e.u. by the crystal is consistent with a reasonable simple assumption about the distribution of hydrogen bonds.It is suggested, by analogy, that the barrier to the hydroxyl group rotation in ethyl alcohol should be about 1000 cal./mole.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71293/2/JCPSA6-18-3-361-1.pd

    The Logic of Uncertainty and Executive Discretion in Decision Making: The Dallas-Fort Worth Metroplex Ebola Response

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    This paper addresses an important question: what can a highly complex public health situation such as the Dallas-Fort Worth Ebola outbreak tell us about the use of discretion by executive level public administrators? The public administration literature is rich with evidence of street-level bureaucratic discretion, but has not explored executive level discretion decision making. The authors argue that in highly complex situations of uncertainty, such as in the case of the Dallas-Fort Worth regional Ebola emergency response, the executive use of discretion translates to decisions under the conditions of uncertainty. This article theorizes a logic of uncertainty when two important assumptions exist; the situation is absent a plan to guide decision making, and the decision makers lack any previous precedent with the situation. Results indicate that when survey respondents departed from their emergency management plan, and planned as the event folded, they were more likely to use executive discretion decision making

    Book Reviews

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    Mean-atom-trajectory model for the velocity autocorrelation function of monatomic liquids

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    We present a model for the motion of an average atom in a liquid or supercooled liquid state and apply it to calculations of the velocity autocorrelation function Z(t)Z(t) and diffusion coefficient DD. The model trajectory consists of oscillations at a distribution of frequencies characteristic of the normal modes of a single potential valley, interspersed with position- and velocity-conserving transits to similar adjacent valleys. The resulting predictions for Z(t)Z(t) and DD agree remarkably well with MD simulations of Na at up to almost three times its melting temperature. Two independent processes in the model relax velocity autocorrelations: (a) dephasing due to the presence of many frequency components, which operates at all temperatures but which produces no diffusion, and (b) the transit process, which increases with increasing temperature and which produces diffusion. Because the model provides a single-atom trajectory in real space and time, including transits, it may be used to calculate all single-atom correlation functions.Comment: LaTeX, 8 figs. This is an updated version of cond-mat/0002057 and cond-mat/0002058 combined Minor changes made to coincide with published versio

    Development and Characterisation of a Gas System and its Associated Slow-Control System for an ATLAS Small-Strip Thin Gap Chamber Testing Facility

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    A quality assurance and performance qualification laboratory was built at McGill University for the Canadian-made small-strip Thin Gap Chamber (sTGC) muon detectors produced for the 2019-2020 ATLAS experiment muon spectrometer upgrade. The facility uses cosmic rays as a muon source to ionise the quenching gas mixture of pentane and carbon dioxide flowing through the sTGC detector. A gas system was developed and characterised for this purpose, with a simple and efficient gas condenser design utilizing a Peltier thermoelectric cooler (TEC). The gas system was tested to provide the desired 45 vol% pentane concentration. For continuous operations, a state-machine system was implemented with alerting and remote monitoring features to run all cosmic-ray data-acquisition associated slow-control systems, such as high/low voltage, gas system and environmental monitoring, in a safe and continuous mode, even in the absence of an operator.Comment: 23 pages, LaTeX, 14 figures, 4 tables, proof corrections for Journal of Instrumentation (JINST), including corrected Fig. 8b
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