300 research outputs found
General properties and analytical approximations of photorefractive solitons
We investigate general properties of spatial 1-dimensional bright
photorefractive solitons and suggest various analytical approximations for the
soliton profile and the half width, both depending on an intensity parameter r
A Hierarchical Scheduling Model for Dynamic Soft-Realtime System
We present a new hierarchical approximation and scheduling approach for applications and tasks with multiple modes on a single processor. Our model allows for a temporal and spatial distribution of the feasibility problem for a variable set of tasks with non-deterministic and fluctuating costs at runtime. In case of overloads an optimal degradation strategy selects one of several application modes or even temporarily deactivates applications. Hence, transient and permanent bottlenecks can be overcome with an optimal system quality, which is dynamically decided. This paper gives the first comprehensive and complete overview of all aspects of our research, including a novel CBS concept to confine entire applications, an evaluation of our system by using a video-on-demand application, an outline for adding further resource dimension, and aspects of our protoype implementation based on RTSJ
Differences in Physician Use of Electronic Health Records: Development of a Scale Assessing Individual Factors Influencing Physician Actualization
Electronic health records (EHRs) are one of the most talked about topics within and surrounding health care organizations and the health care system in the United States; however, the U.S. has been slow to implement these computerized medical record systems into their organizations. One of the factors often overlooked regarding the implementation of EHRs, is the role of individual health care professionals and the effects produced by their interactions with the EHR as they perform their job duties throughout the day. Using a Theory of Organization-EHR Affordance Actualization as a guiding framework, the focus of this dissertation is to examine the factors that influence how physicians use the EHR at the individual-level during clinical interactions by analyzing physician perceptions of their interaction with the EHR while providing patient care in the exam room and how it influences their work process. A mixed methods approach was used to identify the affordances, EHR features, factors that influence EHR use, and individual physician characteristics that produce the visible effects of EHR use during the clinical encounter when individual physicians interact with the EHR.
The findings of this study confirm the identification of individual level affordances proposed by Strong and colleagues and propose three additional affordances. This study also identified additional features that should be taken into consideration when investigating individual level affordance actualization. Finally, this study provides a survey tool for practice managers, health care executives, trainers, and vendors to use in order to better understand the individual user characteristics of their physicians, predict their patterns of use based on these user characteristics, and thus tailor their training to enhance affordance actualization and organizational goal attainment
Chinas Energiediplomatie: Kooperation oder Konkurrenz in Asien?: Aus chinesischen Fachzeitschriften
Die GewĂ€hrleistung einer sicheren Energieversorgung ist weltweit eine der bedeutendsten Herausforderungen des 21. Jahrhunderts. Insbesondere Chinas enormer Energiebedarf und der dadurch verschĂ€rfte Wettbewerb um die verbleibenden Energie-Ressourcen wirft heute mehr denn je die Frage nach Kooperation oder Konkurrenz in Asien auf. Dies spiegelt sich auch in der Tatsache wider, dass die Energiediplomatie der Volksrepublik als Teil der auĂenpolitischen Gesamtstrategie die aktuelle wissenschaftliche Debatte in chinesischen Fachzeitschriften dominiert. (Autorenreferat
Receiver Mount Design, Transmitter Depth, and Wind Speed Affect Detection Probability of Acoustic Telemetry Transmitters in a Missouri River Tributary
Background One of the most important considerations for acoustic telemetry study designs is det:ection probability between the transmitter and the receiver. Variation in environmental (i.e., wind and flow) and abiotic (i.e., bathymetry) conditions among aquatic systems can lead to differences in detection probability temporally or between systems. In this study we evaluate the effect of distance, receiver mount design, transmitter depth, and wind speed on detection probabilities of two models of acoustic transmitters in a mid-sized river. InnovaSea V16-6H (hereafter V16) and V13-1L (hereafter V13) tags were deployed in the James River, SD at 0.36 m (deep) and 2.29 m (V16 tag) or 1.98 m (V13 tag; shallow) above the benthic surface downstream of InnovaSea VR2W stationary receivers at distances of 100, 200, or 300 m. We used two receiver mount designs that included a fixed position within a PVC pipe on the downstream side of a bridge piling or a metal frame deployed in the middle of the river channel. Tags were deployed for 72 h at each location, and hourly detections were summarized. We evaluated downstream distance, receiver mount design, tag depth, and wind effects on tag detection using Bayesian logistic regression. Results: Detection probability decreased as distance increased for all combinations of tag types and mount designs and varied from nearly 100% at 100 m to less than 10% at 300 m. The V16 transmitter had greater detection probability by the receiver mounted in the pipe than in the midriver frame. For both mounts, the deep V16 transmitter had greater detection probability than the V16 shallow transmitter. Detection probability of the V13 transmitter was similar between receiver mounts or transmitter depths. Wind speed had a negative impact on detection probabilities of both transmitter types and depths, except the deep V16 transmitter. Conclusions: Deploying acoustic receivers in PVC pipes rather than midriver frames provided greater downstream detection probabilities for V16 transmitters under conditions evaluated in this study. In addition, V16 transmitters had greater detection probabilities when positioned deep within the water column rather than near the surface. We also demonstrated that wind speed can have a negative impact on detection probabilities
Isotopic Insights into Biological Regulation of Zinc in Contaminated Systems
AbstractAquatic organisms use a variety ofbiogeochemical reactions to regulate essential and non-essential trace metals. Many of these mechanisms can lead to isotopic fractionation, thus measurement of metal isotopes may yield insights into the processes by which organisms respond to metal exposure. We illustrate these concepts with two case studies, one involving an intra- and the other an extra-cellular mechanism of Zn sequestration. In the first study, the mayflyNeocloeontrianguliferwas grown in the laboratory, and fed a diet of Zn-doped diatoms at Zn levels exceeding the requirements for normal mayfly life functions. The N. trianguliferlarvae consumed the diatoms and retained their Zn isotopic signature. Upon metamorphosis, the subimago life stage lost Zn mass either in the exuvia or by excretion, and the Zn retainedwas isotopically enriched. Thus, Zn uptake is non-fractionating, but Zn regulation favors the lighter isotope. Thus the Zn remaining in the subimago was isotopically heavier. In the second study, Zn was adsorbed on the cell walls and exopolysaccharide secretions of cyanobacteria, which favored the heavier Zn isotope.Continued adsorption eventually resulted in nucleation and biomineralization of hydrozincite {Zn5(CO3)2(OH)6}. These case studies demonstrate the utility of Zn isotopes to provide insights into how aquatic insects respond to metal exposure
Loss of Potential Aquatic-Terrestrial Subsidies Along the Missouri River Floodplain
The floodplains of large rivers have been heavily modified due to riparian development and channel modifications, both of which can eliminate shallow off-channel habitats. The importance of these habitats for aquatic organisms like fishes is well studied. However, loss of off-channel habitat also eliminates habitats for the production of emerging aquatic insects, which subsidize riparian consumers in terrestrial food webs. We used field collections of insect emergence, historical mapping, and statistical modeling to estimate the loss of insect emergence due to channel modifications along eight segments of the Missouri River (USA), encompassing 1566 river km, between 1890 and 2012. We estimate annual production of emerging aquatic insects declined by a median of 36,000 kgC (95% CrI: 3000 to 450,000) between 1890 and 2012 (a 34% loss), due to the loss of surface area in backwaters and related off-channel habitats. Under a conservative assumption that riparian birds obtain 24% of their annual energy budget from adult aquatic insects, this amount of insect loss would be enough to subsidize approximately 790,000 riparan woodland birds during the breeding and nesting period (May to August; 95% CrI: 57,000 to 10,000,000). Most of the loss is concentrated in the lower reaches of the Missouri River, which historically had a wide floodplain, a meandering channel, and a high density of off-channel habitats, but which were substantially reduced due to channelization and bank stabilization. Our results indicate that the loss of off-channel habitats in large river floodplains has the potential to substantially affect energy availability for riparian insectivores, further demonstrating the importance of maintaining and restoring these habitats for linked aquatic-terrestrial ecosystems
The ethics of (not) giving back
Recent concerns with academic research 'giving back' and 'having impact' are encouraging the adoption of various practices through which academics are able to share research findings with host communities. While we support the laudable principles behind these efforts, in this contribution we reflect on the viability of such practices in relation to overseas, undergraduate fieldclasses. Drawing on our experiences of leading and teaching on a range of international fieldclasses, we explore the complexities of giving back and caution against a drift towards universalising such practices in specific ways. Instead we call for greater critical honesty as to the potential for fieldclasses to give back in multiple ways and the need to avoid inadvertently doing harm when seeking to engage in ethical practices
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