3,355 research outputs found
Investigation of conductive thermal control coatings by a contactless method in vacuo
A technique for determining the conductance per unit area of thermal control coatings for electrostatically clean spacecraft is described. In order to simulate orbital conditions more closely, current-density-voltage (j-V) curves are obtained by a contactless method in which the paint on an aluminum substrate is the anode of a vacuum diode configuration with a tungsten filament cathode. Conductances per unit area which satisfy the International Sun Earth Explorer (ISEE) requirement were observed on black paints containing carbon and in white and green paints filled with zinc oxide which were fired in order to induce defect conductivity. Because of surface effects and the nonhomogeneous nature of paints, large discrepancies were found between measurements with the contactless method and measurements employing metallic contacts, particularly at low current densities. Therefore, measurements with metallic contacts are considered to be of questionable value in deciding the suitability of coatings for electrostatic charge control
Arthropod diversity in peas with normal or reduced waxy bloom
Crop traits can alter economically important interactions between plants, pests, and biological control agents. For example, a reduced waxy bloom on the surface of pea plants alters interactions between pea aphids and their natural enemies. In this study, we assess whether the effect of wax reduction extends beyond the 2 or 3 arthropod species closely associated with the plants and into the structure of the broader arthropod community of over 200 taxa at our site. We sampled arthropods on lines of peas with normal and reduced wax in Latah Co., Idaho using pitfall traps within randomly assigned pairs of 5 × 5 meter plots. During the 1998 and 1999 growing seasons, we collected 12,113 individual arthropods from 221 unambiguously identified morphospecies. The number of individuals collected from each morphospecies responded idiosyncratically to the reduced wax peas. To test whether arthropod community structure differed between the collections from plots having peas with normal or reduced wax, we performed a randomization test. The collection from peas with reduced wax had higher species evenness and thus higher community diversity despite having lower species richness. Our results demonstrate the potential of a single plant trait, epicuticular wax, to affect a community of arthropods. Two pests of peas had opposite responses to peas with reduced wax. The number of pea aphids collected was greater from peas with normal wax peas than those with reduced wax. In contrast, the number of pea leaf weevils collected was greater from peas with reduced wax
Toxicity of thermal degradation products of spacecraft materials
Three polymeric materials were evaluated for relative toxicity of their pyrolysis products to rats by inhalation: Y-7683 (LS 200), Y-7684 (Vonar 3 on Fiberglass), and Y-7685 (Vonar 3 on N W Polyester). Criteria employed for assessing relative toxicity were (1) lethality from in-chamber pyrolysis, (2) lethality from an outside-of-chamber pyrolysis MSTL Procedure, and (3) disruption of trained rats' shock-avoidance performance during sub-lethal exposures to in-chamber pyrolysis of the materials
The role of the individual in the coming era of process-based therapy
For decades the development of evidence-based therapy has been based on experimental tests of protocols designed to impact psychiatric syndromes. As this paradigm weakens, a more process-based therapy approach is rising in its place, focused on how to best target and change core biopsychosocial processes in specific situations for given goals with given clients. This is an inherently more idiographic question than has normally been at issue in evidence-based therapy over the last few decades. In this article we explore methods of assessment and analysis that can integrate idiographic and nomothetic approaches in a process-based era.Accepted manuscrip
Enhancement and suppression effects resulting from information structuring in sentences
Information structuring through the use of cleft sentences increases the processing efficiency of references to elements within the scope of focus. Furthermore, there is evidence that putting certain types of emphasis on individual words not only enhances their subsequent processing, but also protects these words from becoming suppressed in the wake of subsequent information, suggesting mechanisms of enhancement and suppression. In Experiment 1, we showed that clefted constructions facilitate the integration of subsequent sentences that make reference to elements within the scope of focus, and that they decrease the efficiency with reference to elements outside of the scope of focus. In Experiment 2, using an auditory text-change-detection paradigm, we showed that focus has similar effects on the strength of memory representations. These results add to the evidence for enhancement and suppression as mechanisms of sentence processing and clarify that the effects occur within sentences having a marked focus structure
A computational approach to implicit entities and events in text and discourse
In this paper we will focus on the notion of “implicit”
or lexically unexpressed linguistic elements that are
nonetheless necessary for a complete semantic interpretation
of a text. We refer to “entities” and “events” because
the recovery of the implicit material may affect all the modules
of a system for semantic processing, from the grammatically
guided components to the inferential and reasoning
ones. Reference to the system GETARUNS offers one possible
implementation of the algorithms and procedures needed
to cope with the problem and enables us to deal with all the
spectrum of phenomena. The paper will address at first the
following three types of “implicit” entities and events:
– the grammatical ones, as suggested by a linguistic theories
like LFG or similar generative theories;
– the semantic ones suggested in the FrameNet project, i.e.
CNI, DNI, INI;
– the pragmatic ones: here we will present a theory and an
implementation for the recovery of implicit entities and
events of (non-) standard implicatures.
In particular we will show how the use of commonsense
knowledge may fruitfully contribute to find relevant implied
meanings. Last Implicit Entity only touched on, though for
lack of space, is the Subject of Point of View, which is computed
by Semantic Informational Structure and contributes
the intended entity from whose point of view a given subjective
statement is expressed
Deploying Big Data To Crack The Genotype To Phenotype Code
Mechanistically connecting genotypes to phenotypes is a longstanding and central mission of biology. Deciphering these connections will unite questions and datasets across all scales from molecules to ecosystems. Although high-throughput sequencing has provided a rich platform on which to launch this effort, tools for deciphering mechanisms further along the genome to phenome pipeline remain limited. Machine learning approaches and other emerging computational tools hold the promise of augmenting human efforts to overcome these obstacles. This vision paper is the result of a Reintegrating Biology Workshop, bringing together the perspectives of integrative and comparative biologists to survey challenges and opportunities in cracking the genotype to phenotype code and thereby generating predictive frameworks across biological scales. Key recommendations include: promoting the development of minimum “best practices” for the experimental design and collection of data; fostering sustained and long-term data repositories; promoting programs that recruit, train, and retain a diversity of talent and providing funding to effectively support these highly cross-disciplinary efforts. We follow this discussion by highlighting a few specific transformative research opportunities that will be advanced by these efforts
Characterization and modulation of Langmuir circulation in Chesapeake Bay
Author Posting. © American Meteorological Society, 2015. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 45 (2015): 2621–2639, doi:10.1175/JPO-D-14-0239.1.Measurements made as part of a large-scale experiment to examine wind-driven circulation and mixing in Chesapeake Bay demonstrate that circulations consistent with Langmuir circulation play an important role in surface boundary layer dynamics. Under conditions when the turbulent Langmuir number Lat is low (<0.5), the surface mixed layer is characterized by 1) elevated vertical turbulent kinetic energy; 2) decreased anisotropy; 3) negative vertical velocity skewness indicative of strong/narrow downwelling and weak/broad upwelling; and 4) strong negative correlations between low-frequency vertical velocity and the velocity in the direction of wave propagation. These characteristics appear to be primarily the result of the vortex force associated with the surface wave field, but convection driven by a destabilizing heat flux is observed and appears to contribute significantly to the observed negative vertical velocity skewness.
Conditions that favor convection usually also have strong Langmuir forcing, and these two processes probably both contribute to the surface mixed layer turbulence. Conditions in which traditional stress-driven turbulence is important are limited in this dataset. Unlike other shallow coastal systems where full water column Langmuir circulation has been observed, the salinity stratification in Chesapeake Bay is nearly always strong enough to prevent full-depth circulation from developing.The funding for this research was provided by the National Science Foundation Grants OCE-1339032 and OCE-1338518.2016-04-0
A Survey of Ramp and Stair Use among Older Adults
Forty-three community-dwelling adults aged 57 to 95 participated in survey exploring characteristics of ramp use by older ambulant people. Twenty-three respondents said they ascended ramps instead of stairs most of the time, and 14 said they ascended ramps some of the time. Similar numbers were reported for descent. Overall, respondents felt less fatigued, less likely to trip, and more comfortable when using ramps rather than stairs for ascending one level. When descending one level, balance, tripping, and comfort were the strongest determinants of ramp use. Respondents indicated that descent was more problematic, particularly in regard to balance and tripping. The presence of handrails often determined the choice of route. Results from this survey provided the basis for an experiment evaluating the abilities of older people to traverse ramps of various slopes. The ADA Accessibility Guidelines implicitly assume that a ramp accommodates everyone. This study indicates that entrances should have both ramps and stairs.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline
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