2,482 research outputs found
Evaluation of Ocean Color Scanner (OCS) photographic and digital data: Santa Barbara Channel test site, 29 October 1975 overflight
A summary of Ocean Color Scanner data was examined to evaluate detection and discrimination capabilities of the system for marine resources, oil pollution and man-made sea surface targets of opportunity in the Santa Barbara Channel. Assessment of the utility of OCS for the determination of sediment transport patterns along the coastal zone was a secondary goal. Data products provided 1975 overflight were in digital and analog formats. In evaluating the OCS data, automated and manual procedures were employed. A total of four channels of data in digital format were analyzed, as well as three channels of color combined imagery, and four channels of black and white imagery. In addition, 1:120,000 scale color infrared imagery acquired simultaneously with the OCS data were provided for comparative analysis purposes
The use of indicators for unobservable product qualities: inferences based on consumer sorting
Using the dietary supplement black cohosh to demonstrate our method, we employ data on a product characteristic unobservable to consumers to decompose the contribution to consumersâ valuations of observable characteristics into surrogate indicator and direct components. Because consumers are not all âexpert appraisersâ of the unobservable characteristic, the measured relationship of indicators to the unobservable quality is generally not the one consumers perceive. Consequently, biases that depend upon the nature of consumersâ ineptitude are introduced into the component estimation. The researcherâs inference problem is solved by recognizing that consumers with greater appraisal expertise sort disproportionately to higher quality products. This enables feasible measurement of inept consumersâ relative valuations and conjectures through separate hedonic estimation on high- and low-quality product subsamples. We find that, relative to experts, inept consumers likely underestimate the value of most observable characteristics in indicating black cohosh product authenticity; however they overweight online product ratings.hedonic analysis; surrogate indicators; asymmetric information; pricing strategy; product strategy
Monitoring surface resonances on Co2MnSi(100) by spin-resolved photoelectron spectroscopy
The magnitude of the spin polarization at the Fermi level of ferromagnetic
materials at room temperature is a key property for spintronics. Investigating
the Heusler compound CoMnSi a value of 93 for the spin polarization has
been observed at room temperature, where the high spin polarization is related
to a stable surface resonance in the majority band extending deep into the
bulk. In particular, we identified in our spectroscopical analysis that this
surface resonance is embedded in the bulk continuum with a strong coupling to
the majority bulk states. The resonance behaves very bulk-like, as it extends
over the first six atomic layers of the corresponding (001)-surface. Our study
includes experimental investigations, where the bulk electronic structure as
well as surface-related features have been investigated using spin-resolved
photoelectron spectroscopy (SR-UPS) and for a larger probing depth
spin-integrated high energy x-ray photoemission spectroscopy (HAXPES). The
results are interpreted in comparison with first-principles band structure and
photoemission calculations which consider all relativistic, surface and
high-energy effects properly.Comment: 9 pages, 8 figures, Heusler alloy, electronic structure and
photoemissio
An experimental investigation of chatter effects on tool life
Tool wear is one of the most important considerations in machining operations as it affects surface quality and integrity, productivity and cost. The most commonly used model for tool life analysis is the one proposed by F.W. Taylor about a century ago. Although the extended form of this equation includes the effects of important cutting conditions on tool wear, tool life studies are mostly performed under stable cutting conditions where the effect of chatter vibrations are not considered. This paper presents an empirical attempt to understand tool life under vibratory cutting conditions. Tool wear data are collected in turning and milling on different work materials under stable and chatter conditions. The effects of cutting conditions as well as severity of chatter on tool life are analyzed. The results indicate significant reduction in tool life due to chatter as expected. They also show that the severity of chatter, and thus the vibration amplitude, strongly reduces the life of cutting tools. These results can be useful in evaluating the real cost of chatter by including the reduced tool life. They can also be useful in justifying the cost of chatter suppression and more rigid machining systems
Introduction to the Anti-Racism Virtual Issue of the Journal of Occupational Science
The anti-racism virtual issue of the Journal of Occupational Science (JOS) came about after the Editorial Board expressed its commitment to anti-racist work, publishing the position statement âA Pledge to Mobilize Against Racismâ (Stanley et al., 2020). In this statement, the Board promised to republish a collection of articles to call attention to racism and its impact on individualsâ doing and society. The intent is to stimulate critical reflection on the contribution occupational scientists can make to exposing and countering racism in everyday doing. As such, the anti-racism virtual issue helps meet a pressing need to recognize the power of occupation in shaping and reproducing social ideologies, attitudes, and behaviors. We, the authors, urge all occupational scientists to build on this knowledge and continue learning about racism to better understand and address how its different dimensions manifest through occupation and everyday life
Conceptual modeling for adaptive environmental assessment and management in the Barycz Valley, Lower Silesia, Poland
The complexity of interactions in socio-ecological systems makes it very difficult to plan and implement policies successfully. Traditional environmental management and assessment techniques produce unsatisfactory results because they often ignore facets of system structure that underlie complexity: delays, feedbacks, and non-linearities. Assuming that causes are linked in a linear chain, they concentrate on technological developments (âhard pathâ) as the only solutions to environmental problems. Adaptive Management is recognized as a promising alternative approach directly addressing links between social and ecological systems and involving stakeholders in the analysis and decision process. This âsoft pathâ requires special tools to facilitate collaboration between âexpertsâ and stakeholders in analyzing complex situations and prioritizing policies and actions. We have applied conceptual modeling to increase communication, understanding and commitment in the project of seven NGOs âSustainable Regional Development in the Odra Catchmentâ. The main goal was to help our NGO partners to facilitate their efforts related to developing sustainable policies and practices to respond to large-scale challenges (EU accession, global changes in climate and economy) to their natural, economic and socio-cultural heritages. Among the variety of sustainability issues explored by these NGOs, two (extensive agricultural practices and âgreenâ local products) were examined by using Adaptive Management (AM) as a framework that would link analysis, discussion, research, actions and monitoring. Within the AM framework the project coordinators used tools of systems analysis (Mental Model Mapping) to facilitate discussions in which NGO professionals and local stakeholders could graphically diagram and study their understanding of what factors interacted and how they affect the regionâs sustainability. These discussions produced larger-scale Regional Sustainability Models as well as more detailed sub-models of particular factors, processes, and feedback loops that appear critical to a sustainable future. The Regional Sustainability Model was used to identify a subset of key interacting factors (variables). For each variable, several sustainability indicators were suggested. The growing understanding and acceptance of the AM framework and systems analysis created a momentum both locally and within the region, which makes continued successful use of these indicators quite likely. In contrast to expert-driven projects that inject outside knowledge into a local context, this project established a broad basis for stakeholder-driven discussion that is articulated into goals, objectives, conceptual models, and indicators. The ability to learn and adapt in the AM framework increases the capacity to innovate and find policies and practices that enhance resilience and sustainability in a world in transition
In vitro effects of 10,10'-oxybisphenoxarsine on isolated rat liver mitochondria
10,10'-Oxybisphenoxarsine (OBPA), a trivalent, heterocyclic organoarsenical, is a potent, broad spectrum antimicrobial agent often incorporated into plasticized polyvinyl chlorides. Although highly toxic, the mechanism of OBPA toxicity is unknown. Since it is hepatotoxic, we investigated the in vitro effects of OBPA on rat liver mitochondria. Isolated mitochondria were incubated with 1 to 8 [mu] OBPA and oxygen consumption was monitored polarographically. State 3 respiration of [alpha]-ketoglutarate, pyruvate, isocitrate, and succinate was rapidly inhibited. OBPA also uncoupled oxidative phosphorylation, although this was masked, at higher concentrations, by progressive respiratory inhibition. The electron transport chain appeared unaffected by OBPA, as measured by NADH oxidation, but several tricarboxcylic acid cycle dehydrogenases were inhibited. This inhibition was prevented and, in some cases, reversed by glutathione. It is likely that OBPA, like other trivalent organoarsenicals, exerts its toxic effects by reacting with vital mitochondrial sulfhydryl groups.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24072/1/0000324.pd
Efficient metallic spintronic emitters of ultrabroadband terahertz radiation
Terahertz electromagnetic radiation is extremely useful for numerous
applications such as imaging and spectroscopy. Therefore, it is highly
desirable to have an efficient table-top emitter covering the 1-to-30-THz
window whilst being driven by a low-cost, low-power femtosecond laser
oscillator. So far, all solid-state emitters solely exploit physics related to
the electron charge and deliver emission spectra with substantial gaps. Here,
we take advantage of the electron spin to realize a conceptually new terahertz
source which relies on tailored fundamental spintronic and photonic phenomena
in magnetic metal multilayers: ultrafast photo-induced spin currents, the
inverse spin-Hall effect and a broadband Fabry-P\'erot resonance. Guided by an
analytical model, such spintronic route offers unique possibilities for
systematic optimization. We find that a 5.8-nm-thick W/CoFeB/Pt trilayer
generates ultrashort pulses fully covering the 1-to-30-THz range. Our novel
source outperforms laser-oscillator-driven emitters such as ZnTe(110) crystals
in terms of bandwidth, terahertz-field amplitude, flexibility, scalability and
cost.Comment: 18 pages, 10 figure
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