266 research outputs found
Prediction of Nitrogen Inputs for Sugar Beet.An Evaluation of Soil Tests and Soil
End of Project ReportCurrently, advice on nitrogen (N) use for tillage crops employs an index
system based on crop management. However, there has not been a
systematic evaluation of several of its components or of the relevance of
soil tests, alone or in conjunction. The objective of the current study,
therefore, was to evaluate relevant soil management data, various
biological and chemical soil tests, and measurements of Nmin (NH4 +
NO3) in the root profile, for prediction of fertiliser N requirements. The
data used in the study were derived from a data bank of results of field
and laboratory experiments for sugar beet.
The following topics were addressed: selection of regression models based
on soil management criteria; sustainability of contribution of soil N
reserves; limitations of soil tests for N; long-term trends in Nmin and
biomass C; relationship of mineral-N flush with biomass C; relevance of
Nmin with growing-season rainfall; implications of winter rainfall for
residual effects and their justification within the current soil N index.European Union
Structural Funding (EAGGF
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Measuring configural spatial knowledge: Individual differences in correlations between pointing and shortcutting.
People use environmental knowledge to maintain a sense of direction in daily life. This knowledge is typically measured by having people point to unseen locations (judgments of relative direction) or navigate efficiently in the environment (shortcutting). Some people can estimate directions precisely, while others point randomly. Similarly, some people take shortcuts not experienced during learning, while others mainly follow learned paths. Notably, few studies have directly tested the correlation between pointing and shortcutting performance. We compared pointing and shortcutting in two experiments, one using desktop virtual reality (VR) (N = 57) and one using immersive VR (N = 48). Participants learned a new environment by following a fixed route and were then asked to point to unseen locations and navigate to targets by the shortest path. Participants performance was clustered into two groups using K-means clustering. One (lower ability) group pointed randomly and showed low internal consistency across trials in pointing, but were able to find efficient routes, and their pointing and efficiency scores were not correlated. The others (higher ability) pointed precisely, navigated by efficient routes, and their pointing and efficiency scores were correlated. These results suggest that with the same egocentric learning experience, the correlation between pointing and shortcutting depends on participants learning ability, and internal consistency and discriminating power of the measures. Inconsistency and limited discriminating power can lead to low correlations and mask factors driving human variation. Psychometric properties, largely under-reported in spatial cognition, can advance our understanding of individual differences and cognitive processes for complex spatial tasks
The cognitive science of visual-spatial displays: Implications for design
Abstract This paper reviews cognitive science perspectives on the design of visual-spatial displays and introduces the other papers in this topic. It begins by classifying different types of visual-spatial displays, followed by a discussion of ways in which visual-spatial displays augment cognition and an overview of the perceptual and cognitive processes involved in using displays. The paper then argues for the importance of cognitive science methods to the design of visual displays and reviews some of the main principles of display design that have emerged from these approaches to date. Cognitive scientists have had good success in characterizing the performance of well-defined tasks with relatively simple visual displays, but many challenges remain in understanding the use of complex displays for ill-defined tasks. Current research exemplified by the papers in this topic extends empirical approaches to new displays and domains, informs the development of general principles of graphic design, and addresses current challenges in display design raised by the recent explosion in availability of complex data sets and new technologies for visualizing and interacting with these data
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Individual Differences In Mechanical Ability
People who understand mechanical systems can infer the principles of operation of an
unfamiliar device from their knowledge of the device's components and their mechanical
interactions. Individuals vary in their ability to make this tjrpe of inference. This paper
describes studies of performance in psychometric tests of mechanical ability. Based on
subjects' retrospective protocols and response patterns, it was possible to identify rules of
mechanical reasoning which accounted for the performance of subjects who differ in
mechanical ability. The rules are explicitely stated in a simulation model which demonstrates
the sufficiency of the rules by producing the kinds of responses observed in the subjects.
Three factors are proposed as the sources of individual differences in mechanical ability: <1|
ability to correctly identify which attributes of a system are relevant to its mechanical
function, (2) ability to use rules consistently, and (3| ability to quantitatively combine
information about two or more relevant attributes
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Benefit of Varying Navigation Strategies in Robot Teams
Inspired by recent human studies, this paper investigates the benefits of employing varying navigation strategies in robot teams. We explore how mixed navigation strategies impact task completion time, environment exploration, and overall system effectiveness in multi-robot systems. Experiments were conducted in a simulated rectangular environment using Clearpath PR2 robots and evaluated different navigation strategies observed in humans: 1) Route (RT) knowledge where agents follow a predefined path, 2) Survey (SW) knowledge where agents take the shortest path while avoiding obstacles, 3) Mixed strategies with varying proportions, such as 40% RT and 60% SW (0.4RT 0.6SW) and 60% RT and 40% SW (0.6RT 0.4SW), and 4) An additional strategy where agents switch from RT to SW 10% of the time (0.9RT 0.1SW). While SW strategy is the most time-efficient, RT strategy covers more of the environment. Mixed strategies offer a balanced trade-off. These findings highlight the advantages of variability in navigation strategies, suggesting benefits in both biological and robotic populations. Additionally, we have observed that human participants in a similar study would start on a route, and then 10% of the time switch to survey. Therefore, we investigate a 90% Route 10% Survey (0.9RT 0.1SW) strategy for individual team members. While a pure Survey strategy is the most efficient regarding time taken and a pure Route strategy covers more of the environment, a mixture of strategies appears to be a beneficial tradeoff between time taken to complete a mission and area coverage. These results highlight the advantages of population variability, suggesting potential benefits in both biological and robotic populations
Visual working memory for connected 3D objects: effects of stimulus complexity, dimensionality and connectivity.
Visual working memory (VWM) is typically measured using arrays of two-dimensional isolated stimuli with simple visual identities (e.g., color or shape), and these studies typically find strong capacity limits. Science, technology, engineering and mathematics (STEM) experts are tasked with reasoning with representations of three-dimensional (3D) connected objects, raising questions about whether those stimuli would be subject to the same limits. Here, we use a color change detection task to examine working memory capacity for 3D objects made up of differently colored cubes. Experiment 1a shows that increasing the number of parts of an object leads to less sensitivity to color changes, while change-irrelevant structural dimensionality (the number of dimensions into which parts of the structure extend) does not. Experiment 1b shows that sensitivity to color changes decreases similarly with increased complexity for multipart 3D connected objects and disconnected 2D squares, while sensitivity is slightly higher with 3D objects. Experiments 2a and 2b find that when other stimulus characteristics, such as size and visual angle, are controlled, change-irrelevant dimensionality and connectivity have no effect on performance. These results suggest that detecting color changes on 3D connected objects and on displays of isolated 2D stimuli are subject to similar set size effects and are not affected by dimensionality and connectivity when these properties are change-irrelevant, ruling out one possible explanation for scientists advantages in storing and manipulating representations of complex 3D objects
Symmetry and spatial ability enhance change detection in visuospatial structures.
Science, Technology, Engineering, and Mathematics (STEM) domains require people to recognize and transform complex visuospatial displays that appear to vastly exceed the limits of visuospatial working memory. Here, we consider possible domain-general mechanisms that may explain this advantage: capitalizing on symmetry, a structural regularity that can produce more efficient representations. Participants briefly viewed a structure made up of three-dimensional connected cubes of different colors, which was either asymmetrical or symmetrical. After a short delay, they were asked to detect a change (colors swapping positions) within a rotated second view. In change trials, the second display always had an asymmetrical structure. The presence of symmetry in the initial view improved change detection, and performance also declined with angular disparity of the encoding and test displays. People with higher spatial ability performed better on the change-detection task, but there was no evidence that they were better at leveraging symmetry than low-spatial individuals. The results suggest that leveraging symmetrical structures can help people of all ability levels exceed typical working memory limits by constructing more efficient representations and substituting resource-demanding mental rotation operations with alternative orientation-independent strategies
Men's information-seeking behavior regarding cancer risk and screening: A meta-narrative systematic review
Objective: Preventive strategies are known to reduce cancer risk and incidence and improve prognosis. Men seldom seek medical information about cancer prevention and risk reduction. The aim of this meta-narrative systematic review was to critically appraise evidence from qualitative, quantitative, and mixed-methods studies that explored men's information-seeking behaviors in relation to cancer prevention and risk reduction. Methods: MEDLINE, CINAHL Plus with Full Text, PsycINFO, PsycARTICLES, Psychology and Behavioral Sciences Collection, Education Full Text, and ERIC were systematically searched for studies published in English between January 1, 2006 and May 30, 2016. A total of 4117 titles were identified; of which, 31 studies were included (21 qualitative studies, 9 quantitative studies, and 1 mixed-methods study). The methodological quality of the studies was appraised by using different tools. Results: Most studies focused on screening for prostate (n = 18) and colorectal cancer (n = 7). Most men were passive information-gatherers rather than active information-seekers. Key sources of information included the Internet for active information-seekers and health care professionals for passive information-gatherers. Barriers to information-seeking included information overload, embarrassment, and fear. Low literacy and health literacy levels were addressed in 3 studies and were identified as impediments to active information-seeking. Facilitators to information-seeking included family support, media, celebrity endorsements, and targeted information. Conclusions: Men's information-seeking behavior regarding cancer risk reduction, prevention, and screening is influenced by several factors. This necessitates targeted interventions aimed at raising awareness of cancer prevention and screening, while accounting for men's informational needs, preferred learning strategies, and literacy levels
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