8,019 research outputs found
Considerations for an Extended Framework for Interactive Epoch-Era Analysis
AbstractEpoch-Era Analysis (EEA) is a framework that supports narrative and computational scenario planning and analysis for both short run and long run futures. Currently EEA is being applied to frame problems faced by the DoD's Engineered Resilient Systems (ERS) efforts. Because of the large amount of data that must be analyzed when extending EEA to large-scale problems, such as those posed by DoD, a “big data” problem is introduced. This motivates the need for extensions to EEA methods that overcome the computational and human cognition issues that arise as a result. The research presented here describes exploratory development of Interactive Epoch-Era Analysis (IEEA) methods, including human interface and reasoning considerations for epoch and era characterizations, as well as single and multi- epoch and era analyses. Visualization techniques and methods for mitigating computational resource restrictions that facilitate improved decision-making are also presented
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Photosynthetic sensitivity to historic meteorological variability for conifers in the eastern Sierra Nevada
Increased climatic variability can impact tree physiological processes beyond what is predicted from changes in mean conditions. We assessed the sensitivity of conifer saplings to spatial and temporal variability in meteorological conditions, taking advantage of the end of California's historic drought and the exceedingly wet winter of 2017. We sought to understand how very dry and very wet conditions constrain photosynthesis and growth in four regionally dominant conifers and whether sensitivity in these processes changes across a 500 m gradient in elevation. All species demonstrated phenotypic plasticity in response to temporal differences in precipitation on both inter-annual and seasonal timescales. Net photosynthesis in Pinus contorta decreased from an early season 2016 average of 12.4 to 6.89 μmol CO2 m-2 s-1 later in the summer, but increased 14.1% between seasons in the wet year. By contrast, elevation had almost no effect on instantaneous photosynthetic gas exchange, CO2 response curve parameters, or stem water potential in any of the years for any of the species. Effects of the heavy snow year (2017) on needle growth differed between elevations. Pinus contorta showed a 38.9% increase in average needle length at the lower two elevations but a 31.6% decrease at the highest site compared to the height of the drought. Despite these differences, biological variation was dampened compared to the physical variation between years, suggesting these trees can effectively withstand substantial meteorological variability. Our results show that these species demonstrated considerable ability to tolerate and recover from an extreme drought event
Hippocampus and retrosplenial cortex combine path integration signals for successful navigation
The current study used fMRI in humans to examine goal-directed navigation in an open field environment. We designed a task that required participants to encode survey-level spatial information and subsequently navigate to a goal location in either first person, third person, or survey perspectives. Critically, no distinguishing landmarks or goal location markers were present in the environment, thereby requiring participants to rely on path integration mechanisms for successful navigation. We focused our analysis on mechanisms related to navigation and mechanisms tracking linear distance to the goal location. Successful navigation required translation of encoded survey-level map information for orientation and implementation of a planned route to the goal. Our results demonstrate that successful first and third person navigation trials recruited the anterior hippocampus more than trials when the goal location was not successfully reached. When examining only successful trials, the retrosplenial and posterior parietal cortices were recruited for goal-directed navigation in both first person and third person perspectives. Unique to first person perspective navigation, the hippocampus was recruited to path integrate self-motion cues with location computations toward the goal location. Last, our results demonstrate that the hippocampus supports goal-directed navigation by actively tracking proximity to the goal throughout navigation. When using path integration mechanisms in first person and third person perspective navigation, the posterior hippocampus was more strongly recruited as participants approach the goal. These findings provide critical insight into the neural mechanisms by which we are able to use map-level representations of our environment to reach our navigational goals
Identity dynamics as a barrier to organizational change
This article seeks to explore the construction of group and professional identities in situations of organizational change. It considers empirical material drawn from a health demonstration project funded by the Scottish Executive Health Department, and uses insights from this project to discuss issues that arise from identity construction(s) and organizational change. In the course of the project studied here, a new organizational form was developed which involved a network arrangement with a voluntary sector organization and the employment of “lay-workers” in what had traditionally been a professional setting. Our analysis of the way actors made sense of their identities reveals that characterizations of both self and other became barriers to the change process. These identity dynamics were significant in determining the way people interpreted and responded to change within this project and which may relate to other change-oriented situations
Temporal and spatial trends in stranding records of cetaceans on the Irish coast, 2002–2014
Using Irish strandings data collected between 2002 and 2014, seasonal and annual trends in the number of strandings for all strandings identified to species level (N ¼ 1480), and for the five most frequently reported species: common dolphin (25.7% of records), harbour porpoise (22.2%), long-finned pilot whale (8.8%), striped dolphin (6.9%) and bottlenose dolphin (6.9%) were investigated. With the exception of bottlenose dolphins, there was a significant linear increase in the number of strandings across years for all species and for all strandings collectively, that were identified to species-level. Only common dolphins demonstrated a significant increase in the proportion of records relative to all other strandings, which may be indicative of a real rise in the number of strandings of this species. Common dolphins and harbour porpoises showed a similar significant difference in monthly strandings, with more strandings occurring during the earlier months of the year.\ud
Significant differences in the gender of stranded animals were found in common, striped, bottlenose and Atlantic white-sided dolphins and sperm and pygmy sperm whales. Live and mass stranding events were primarily comprised of pelagic species. Most strandings occurred on the south and west coasts, with two hotspots for live and mass strandings identified. The patterns and trends identified are discussed in relation to the caveats in interpreting strandings data. Specifically to Ireland, the findings highlight the urgent need to build on the current volunteer reporting network and augment this comprehensive dataset with post-mortem examinations to better understand the cause of the trends identified. The importance of strandings data in informing conservation and management guidelines of these species’ is discussed
Estimating Winning Probabilities in Backgammon Races
In modern backgammon, it is advantageous to know the chances each player has of winning, and to be able to compute the chances without the aid of calculators or pencil and paper. A simple model of backgammon is used to approximate those chances, and a readily computable and sufficiently accurate approximation of that is developed. From there, the model is compared to simulated backgammon games, and the previous approximation is modified to fit the real data
Electric power distribution and load transfer system
A power distribution system includes a plurality of power sources and load transfer units including transistors and diodes connected in series and leading to a common power output, each of the transistors being controller switchable subject to voltage levels of the respective input and output sides of said transistors, and the voltage and current level of said common power output. The system is part of an interconnection scheme in which all but one of the power sources is connected to a single load transfer unit, enabling the survival of at least a single power source with the failure of one of the load transfer units
Electric power distribution and load transfer system
A power distribution system includes a plurality of power sources and load transfer units including transistors and diodes connected in series and leading to a common power output, each of the transistors being controller switchable subject to voltage levels of the respective input and output sides of said transistors, and the voltage and current level of said common power output. The system is part of an interconnection scheme in which all but one of the power sources is connected to a single load transfer unit, enabling the survival of at least a single power source with the failure of one of the load transfer units
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