3,244 research outputs found
The Impact of Pictorial Display on Operator Learning and Performance
The effects of pictorially displayed information on human learning and performance of a simple control task were investigated. The controlled system was a harmonic oscillator and the system response was displayed to subjects as either an animated pendulum or a horizontally moving dot. Results indicated that the pendulum display did not effect performance scores but did significantly effect the learning processes of individual operators. The subjects with the pendulum display demonstrated more vertical internal models early in the experiment and the manner in which their internal models were tuned with practice showed increased variability between subjects
A New Power?: Civil Offenses and Presidential Clemency
Article II of the U.S Constitution empowers presidents to pardon Offences against the United States. The traditional understanding of that power suggests that presidential clemency extends only to crimes. That view, however, is mistaken. This Article shows that presidents may also pardon civil offenses and opens a discussion about how this power could be used by presidents
Biozonation of Deep-Water Lithoherms and Associated Hardgrounds in the Northeastern Straits of Florida
Elongated carbonate mounds ( lithoherms ) oriented parallel to prevailing northerly bottom currents at moderate depths (500-700 m) along the western margin of the Little Bahama Bank exhibit a consistent faunal zonation characterized by attached, suspension-feeding invertebrates. The four most abundant macroepibenthic groups (alcyonarians, crinoids, sponges and stylasterid hydrocorals) dominate all hard substrates examined except upcurrent ends and crests of lithoherms. We recognize three faunal zones on these mounds: a Coral Zone (Lophelia prolifera) restricted to the upcurrent end; a Zoanthid Zone (?Gerardia sp.) along upcurrent crests, and a Crinoid/Alcyonarian Zone along lithoherm flanks and downstream crests. Taxa characteristic of the latter also occur on surrounding, low-relief hardgrounds but are accompanied by additional taxa usually absent from mounds. Intervening unconsolidated sediment is largely barren. Biozonation appears chiefly dependent on current flow regime and secondarily on substrate. The observed zonation occurs over a much smaller areal scale than previously reported for deep-water (non-hydrothermal) hard bottoms. Abrupt, small-scale faunal zonation can no longer automatically be considered as evidence of a shallow-water environment in interpreting fossil assemblages
Multiple exciton generation in nano-crystals revisited: Consistent calculation of the yield based on pump-probe spectroscopy
Multiple exciton generation (MEG) is a process in which more than one exciton
is generated upon the absorption of a high energy photon, typically higher than
two times the band gap, in semiconductor nanocrystals. It can be observed
experimentally using time resolved spectroscopy such as the transient
absorption measurements. Quantification of the MEG yield is usu- ally done by
assuming that the bi-exciton signal is twice the signal from a single exciton.
Herein we show that this assumption is not always justified and may lead to
significant errors in the estimated MEG yields. We develop a methodology to
determine proper scaling factors to the signals from the transient absorption
experiments. Using the methodology we find modest MEG yields in lead
chalcogenide nanocrystals including the nanorods
Concept-Guided Chain-of-Thought Prompting for Pairwise Comparison Scaling of Texts with Large Language Models
Existing text scaling methods often require a large corpus, struggle with
short texts, or require labeled data. We develop a text scaling method that
leverages the pattern recognition capabilities of generative large language
models (LLMs). Specifically, we propose concept-guided chain-of-thought
(CGCoT), which uses prompts designed to summarize ideas and identify target
parties in texts to generate concept-specific breakdowns, in many ways similar
to guidance for human coder content analysis. CGCoT effectively shifts pairwise
text comparisons from a reasoning problem to a pattern recognition problem. We
then pairwise compare concept-specific breakdowns using an LLM. We use the
results of these pairwise comparisons to estimate a scale using the
Bradley-Terry model. We use this approach to scale affective speech on Twitter.
Our measures correlate more strongly with human judgments than alternative
approaches like Wordfish. Besides a small set of pilot data to develop the
CGCoT prompts, our measures require no additional labeled data and produce
binary predictions comparable to a RoBERTa-Large model fine-tuned on thousands
of human-labeled tweets. We demonstrate how combining substantive knowledge
with LLMs can create state-of-the-art measures of abstract concepts.Comment: 26 pages, 2 figure
Point counting on reductions of CM elliptic curves
We give explicit formulas for the number of points on reductions of elliptic
curves with complex multiplication by any imaginary quadratic field. We also
find models for CM -curves in certain cases. This generalizes
earlier results of Gross, Stark, and others.Comment: Minor corrections. To appear in Journal of Number Theor
Cross-country collaboration for physical activity promotion: experiences from the European Union Physical Activity Focal Points Network
Background: An analysis of currently existing partnerships and cross-country collaboration for physical activity (PA) promotion is valuable for understanding how such partnerships operate, and how they impact national PA promotion efforts. This study aimed to outline the formation and development of the European Union's (EU) Physical Activity Focal Points Network, to evaluate its outputs and benefits and to describe its potential and challenges. Methods: A mixed methods approach were employed, including document analysis, semi-structured interviews with key officials and an online evaluation survey with the focal points. Results: The network was founded in 2014. Its main task is to coordinate the national collection of information for the EU's Health-Enhancing Physical Activity (HEPA) Monitoring Framework. Besides collecting data, focal points usually meet twice a year to share best practices and plan activities for the promotion of PA within the EU. The results of the evaluation survey show that participation in the network helped members specify goals for PA promotion, gain more knowledge regarding how to promote PA, identify more opportunities to promote PA in their country and to join a collaborative project with other countries. Conclusions: The study shows that the EU Physical Activity Focal Points Network may serve as an example of successful cross-country collaboration in PA promotion. The network has been able to make a contribution to monitoring the implementation of the EU Council Recommendation on HEPA across sectors in particular and of PA promotion in the EU in general. © 2022 The Author(s). Published by Oxford University Press on behalf of the European Public Health Association.This research was conducted as part of a project funded by the German Federal Ministry of Health (ZMVI1-2520WHO001 and ZMVI1-2521WHO001). The ministry was neither involved in writing this manuscript nor in the decision to submit the article for publication
Light and Vision in the Deep-Sea Benthos: I. Bioluminescence at 500-1000 m Depth in the Bahamian Islands
Bioluminescence is common and well studied in mesopelagic species. However, the extent of bioluminescence in benthic sites of similar depths is far less studied, although the relatively large eyes of benthic fish, crustaceans and cephalopods at bathyal depths suggest the presence of significant biogenic light. Using the Johnson-Sea-Link submersible, we collected numerous species of cnidarians, echinoderms, crustaceans, cephalopods and sponges, as well as one annelid from three sites in the northern Bahamas (500–1000 m depth). Using mechanical and chemical stimulation, we tested the collected species for light emission, and photographed and measured the spectra of the emitted light. In addition, in situ intensified video and still photos were taken of different benthic habitats. Surprisingly, bioluminescence in benthic animals at these sites was far less common than in mesopelagic animals from similar depths, with less than 20% of the collected species emitting light. Bioluminescent taxa comprised two species of anemone (Actinaria), a new genus and species of flabellate Parazoanthidae (formerly Gerardia sp.) (Zoanthidea), three sea pens (Pennatulacea), three bamboo corals (Alcyonacea), the chrysogorgiid coral Chrysogorgia desbonni (Alcyonacea), the caridean shrimp Parapandalus sp. and Heterocarpus ensifer (Decapoda), two holothuroids (Elasipodida and Aspidochirota) and the ophiuroid Ophiochiton ternispinus (Ophiurida). Except for the ophiuroid and the two shrimp, which emitted blue light (peak wavelengths 470 and 455 nm), all the species produced greener light than that measured in most mesopelagic taxa, with the emissions of the pennatulaceans being strongly shifted towards longer wavelengths. In situ observations suggested that bioluminescence associated with these sites was due primarily to light emitted by bioluminescent planktonic species as they struck filter feeders that extended into the water column
Vision and Bioluminescence in the Deep-Sea Benthos
During a NOAA-OER funded research cruise, novel collecting techniques were used to collect live, deep-sea benthic animals for studies of bioluminescence and vision. True color images and emission spectra of bioluminescence were obtained from a number of species, including the spiral octocoral Iridogorgia sp., the sea fan Chrysogorgia sp., the sea pen Umbellula sp., and the caridean shrimp Heterocarpusoryx. Electrophysiological studies were conducted on 3 species of decapod crustaceans collected with methods that limited light damage to their photoreceptors. The caridean shrimp, Bathypalaemonella, collected from 1920m, was always found in association with the bioluminescent spiral octocoral Iridogorgia. While moribund at the surface, enough data were obtained from one specimen to show different wave forms in response to short and long wavelength light, indicative of two different classes of photoreceptor cells. The chirostylid crab, Uroptychusnitidus, found in association with the bioluminescent sea fan, Chrysogorgia sp., also appears to possess two visual pigments, and if further analysis of data supports this preliminary observation, will be the 4th species of deep-sea, non-bioluminescent crustaceans possessing two visual pigments found in association with bioluminescent cnidarians. These four species also share another characteristic–the presence of one or two very long claws, which the crab species are known to use to pick items (possibly plankton stuck in the mucus) off their cnidarian hosts. These data support the previously presented hypothesis (Frank et al. 2012), that these crustaceans may be utilizing their dual visual pigment systems to distinguish between prey and host, based on spectral differences between pelagic and benthic bioluminescence.
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