Showing 131 - 140 of 2039 Items
Underway and moored methods for improving accuracy in measurement of spectral particulate absorption and attenuation
Date: 2010-10-01
Creator: Wayne H. Slade
Emmanuel Boss
Giorgio Dall'olmo
M. Rois Langner
James, Loftin
Michael J. Behrenfeld
Collin Roesler
Toby K. Westberry
Access: Open access
- Optical sensors have distinct advantages when used in ocean observatories, autonomous platforms, and on vessels of opportunity, because of their high-frequency measurements, low power consumption, and the numerous established relationships between optical measurements and biogeochemical variables. However, the issues of biofouling and instrument stability over time remain complicating factors when optical instruments are used over periods longer than several days. Here, a method for obtaining calibration-independent measurements of spectral particle absorption and attenuation is presented. Flow-through optical instrumentation is routinely diverted through a large-surface area 0.2-μm cartridge filter, allowing for the calculation of particle optical properties by differencing temporally adjacent filtered and whole water samples. This approach yields measurements that are independent of drift in instrument calibration. The method has advantages not only for coastally moored deployments, but also for applications in optically clear waters where uncertainties in instrument calibration can be a significant part of the signal measured. The differencing technique is demonstrated using WET Labs (Philomath, Oregon) ac-9 and ac-s multi- and hyperspectral absorption and attenuation meters. For the ac-s sensor, a correction scheme is discussed that utilizes the spectral shape of water absorption in the near-infrared to improve the accuracy of temperature and scattering-corrected spectra. Flow-through particulate absorption measurements are compared with discrete filter-pad measurements and are found to agree well (R = 0.77; rmse = 0.0174 m ). © 2010 American Meteorological Society. 2 -1
Understanding the effect of political advertising on voter turnout: A response to Krasno and Green
Date: 2008-01-01
Creator: Michael M. Franz
Paul Freedman
Ken Goldstein
Travis N. Ridout
Access: Open access
- Krasno and Green have argued that political advertising has no impact on voter turnout. We remain unconvinced by their evidence, given concerns about how they measure the advertising environment, how they measure advertising tone, their choice of modeling techniques and the generalizability of their findings. These differences aside, we strongly agree that political advertising does little to undermine voter participation. © 2008 Southern Political Science Association.
Climate change's impact on key ecosystem services and the human well-being they support in the US
Date: 2013-11-01
Creator: Erik J. Nelson
Peter Kareiva
Mary Ruckelshaus
Katie Arkema
Gary, Geller
Evan Girvetz
Dave Goodrich
Virginia Matzek
Malin Pinsky
Access: Open access
- Climate change alters the functions of ecological systems. As a result, the provision of ecosystem services and the well-being of people that rely on these services are being modified. Climate models portend continued warming and more frequent extreme weather events across the US. Such weather-related disturbances will place a premium on the ecosystem services that people rely on. We discuss some of the observed and anticipated impacts of climate change on ecosystem service provision and livelihoods in the US. We also highlight promising adaptive measures. The challenge will be choosing which adaptive strategies to implement, given limited resources and time. We suggest using dynamic balance sheets or accounts of natural capital and natural assets to prioritize and evaluate national and regional adaptation strategies that involve ecosystem services. © The Ecological Society of America.
The Effects of Corporate Governance on the Innovation Performance of Chinese SMEs
Date: 2013-03-10
Creator: Yao Tang
Daniel Shapiro
Miaojun Wang
Weiying Zhang
Access: Open access
- We investigate the degree to which corporate governance and ownership affects the innovation performance of firms in China with a particular focus on privately owned small and medium enterprises (SMEs). We hypothesize that (1) board-related governance measures will enhance innovation because they improve monitoring and provide access to necessary resources; (2) ownership concentration initially facilitates innovation because large shareholders are more likely to commit to the long-term nature of innovation, and have the incentive to monitor managers whose time horizon may be shorter; however we argue that these effects weaken as large shareholders becomes entrenched at higher levels of concentration; and (3) hiring an external CEO will enhance innovation both by ensuring professional management of the company, and by alleviating the entrenchment possibilities associated with large shareholders. These hypotheses are tested using a unique sample of 370 mostly private and relatively small Chinese firms in Zhejiang province, for the period 2004 to 2006. The results suggest that for this sample, corporate governance and ownership affect innovation activity when measured by patenting activity, but not when measured by new product sales.
Tempered, invariant, positive-definite distributions on SU(1, 1)/{± 1}
Date: 1984-01-01
Creator: William H. Barker
Access: Open access
Prototypes, location, and associative networks (PLAN): Towards a unified theory of cognitive mapping
Date: 1995-01-01
Creator: Eric Chown
Stephen Kaplan
David Kortenkamp
Access: Open access
- An integrated representation of large-scale space, or cognitive map, colled PLAN, is presented that attempts to address a broader spectrum of issues than has been previously attempted in a single model. Rather than examining way-finding as a process separate from the rest of cognition, one or the fundamental goals of this work is to examine how the wayfinding process is integrated into general cognition. One result of this approach is that the model is "heads-up," or scene-based, because it takes advantage of the properties of the human visual system and, particularly, the visual system's split into two pathways. The emphasis on the human location or "where" system is new to cognitive mapping and is port of an attempt to synthesize prototype theory, associative networks and location together in a connectionist system. Not all of PLAN is new, however. Many of its parts have analogues in one or another preexisting theory. What makes PLAN unique is integrating the various components into a coherent whole, and the capacity of this resulting system to speak to a wide range of constraints. Our approach emphasizes adaptiveness; thus, our focus on such issues as ease of use and efficiency of learning. The result is a model that has a stronger relationship both to the environment, and to the ways that humans interact with it, compared with previous models. The resulting model is examined in some detail and compared to other systems. © 1995.
Differential gene expression during compensatory sprouting of dendrites in the auditory system of the cricket Gryllus bimaculatus
Date: 2009-08-01
Creator: H. W. Horch
S. S. McCarthy
S. L. Johansen
J. M. Harris
Access: Open access
- Neurones that lose their presynaptic partners because of injury usually retract or die. However, when the auditory interneurones of the cricket Gryllus bimaculatus are denervated, dendrites respond by growing across the midline and forming novel synapses with the opposite auditory afferents. Suppression subtractive hybridization was used to detect transcriptional changes 3 days after denervation. This is a stage at which we demonstrate robust compensatory dendritic sprouting. Whereas 49 unique candidates were down-regulated, no sufficiently up-regulated candidates were identified at this time point. Several candidates identified in this study are known to influence the translation and degradation of proteins in other systems. The potential role of these factors in the compensatory sprouting of cricket auditory interneurones in response to denervation is discussed. © 2009 The Royal Entomological Society.
The draw-a-computational-creativity-researcher test (DACCRT): Exploring stereotypic images and descriptions of computational creativity
Date: 2019-01-01
Creator: Sarah Harmon
Katie McDonough
Access: Open access
- Prior work investigating student perceptions of scientists has revealed commonly-held beliefs, stereotypes, and even connections to career choices. We adapt the “Draw-A-Scientist” instrument to examine how undergraduates depict computational creativity researchers and the field of computational creativity as a whole. Our results indicate that there are significant differences when students are asked to draw or describe a computer scientist versus a computational creativity researcher. Whether the student is an upper-level or introductory computer science student appears to also influence responses.
Digital Humanities and Italian Studies: Intersections and Oppositions
Date: 2019-07-03
Creator: Crystal Hall
Access: Open access
- This article examines the relationship between two fields of study, Italian Studies and Digital Humanities (DH), by documenting projects that employ digital or computational methods in the study of Italian language, literature, history, and the arts. In a complementary fashion, the author outlines the analytical questions of Italian scholars that have potential to advance inquiry in DH. A final section is devoted to contextualizing DH within the practice of Italian Studies at the institutional, program, and department levels by drawing on research of course offerings and a survey circulated in August 2017. The overall finding is that the area of overlap between DH and Italian Studies is intellectually rich, with increasing (yet still sparse) opportunities to develop specialization in this area.
“I Never Saw as Good a Nature Show Before”: Walt Disney, Environmental Education, and the True-Life Adventures
Date: 2022-01-01
Creator: Charles Dorn
Access: Open access
- Alongside Walt Disney’s animated movies, television programming, and theme parks, scholars have examined The Walt Disney Studios’ True-Life Adventures series of live-action nature documentary films for their impact on popular culture. Historians, however, have mostly overlooked the significance of the True-Life Adventures for student learning about the natural world. Amending this historiographical shortcoming, this essay examines Disney’s innovative approach to wildlife filmmaking, describes viewers’ reactions to the True-Life Adventures’ educational qualities, and investigates the Studios’ efforts to use the films to enter the education market. The study breaks new ground by analyzing seldom accessed documents preserved in theWalt Disney Archives both to reveal how students, teachers, and college and university faculty responded to the films and to examine the extension of the nature documentaries through related media.