1,225 research outputs found
DYMOND: DYnamic MOtif-NoDes Network Generative Model
Motifs, which have been established as building blocks for network structure,
move beyond pair-wise connections to capture longer-range correlations in
connections and activity. In spite of this, there are few generative graph
models that consider higher-order network structures and even fewer that focus
on using motifs in models of dynamic graphs. Most existing generative models
for temporal graphs strictly grow the networks via edge addition, and the
models are evaluated using static graph structure metrics -- which do not
adequately capture the temporal behavior of the network. To address these
issues, in this work we propose DYnamic MOtif-NoDes (DYMOND) -- a generative
model that considers (i) the dynamic changes in overall graph structure using
temporal motif activity and (ii) the roles nodes play in motifs (e.g., one node
plays the hub role in a wedge, while the remaining two act as spokes). We
compare DYMOND to three dynamic graph generative model baselines on real-world
networks and show that DYMOND performs better at generating graph structure and
node behavior similar to the observed network. We also propose a new
methodology to adapt graph structure metrics to better evaluate the temporal
aspect of the network. These metrics take into account the changes in overall
graph structure and the individual nodes' behavior over time.Comment: In Proceedings of the Web Conference 2021 (WWW '21
Predictors of Hospital Readmissions for People with Chronic Conditions
Background: Hospital readmissions remain prominent in health care. Functional, cognitive, and environmental factors predict hospital readmissions but may not be thoroughly measured or addressed prior to discharge.
Method: In this cross-sectional study, people hospitalized with chronic conditions completed measures of self-care function, functional cognition, occupational competence, and environmental impact. They also participated in a phone call or medical records review to identify hospital readmissions within 30 days of discharge. In a group session, occupational therapists who work in acute care completed acceptability, appropriateness, and feasibility measures for the standardized assessments administered to hospital participants.
Results: Occupational competence and functional cognition were significant predictors of hospital readmissions. Therapists rated the Activity Measure of Post-Acute Care (AM-PAC) as the most acceptable, appropriate, and feasible measure for acute care.
Conclusions: Occupational competence and functional cognition are predictors of hospital readmissions in people with chronic conditions. Occupational therapists in acute care should consider supplementing current evaluation practices with standardized measures of functional cognition and occupational competence to identify client needs objectively and initiate post-acute referrals that help clients discharge home successfully. Standardized measures, such as the AM-PAC may be feasible in acute care. Further research on the efficacy of standardized measures in this setting is needed
Predictors of Occupational Competence in People Hospitalized with Chronic Conditions
Background: Chronic diseases limit participation in meaningful daily activities, roles, and routines, which can negatively impact occupational competence, a sense of self, and life satisfaction, especially when hospitalization is required to manage disease symptoms. Standardized measures of occupational competence and related functional, cognitive, and environmental factors may enhance occupational therapists’ ability to identify potential barriers to and make targeted recommendations for self- and health management in the community.
Method: This cross-sectional study investigated occupational competence in patients hospitalized with chronic conditions. The participants completed measures of occupational competence, values, self-care function, environmental impact, and functional cognition while hospitalized.
Results: The participants (n = 51) reported moderate to high levels of occupational competence. The overall regression model was significant. Values, self-care function, and environmental impact were significant predictors of occupational competence.
Conclusion: Values, self-care function, and environmental impact predict occupational competence in people hospitalized with chronic conditions. Occupational therapists should incorporate standardized measures of occupational competence, values, self-care function, and environmental impact into current evaluation practices to support recommendations for follow-up care and community supports. Future research should include a larger sample that is more representative of an occupational therapy caseload and incorporate alternative measures of functional cognition to better measure this construct
Two-Stage Passive Vibration Isolator
The design and testing of a structural system were implemented to hold the optics of the planned Space Interferometry Mission (SIM) at positions and orientations characterized by vibrational translation and rotation errors of no more than a few nanometers or a few milliarcseconds, respectively. Much of the effort was devoted to a test bed for verifying the predicted behavior of a vibration- isolation structural subsystem working together with an active control system for positioning and orienting the SIM optics. There was considerable emphasis on the vibration-isolation subsystem, which was passive and comprised two stages. The main sources of vibration were six reaction wheels in an assembly denoted the "backpack." The first vibration-isolation stage consisted of hexapod isolator mounts - one for each reaction wheel - characterized by a natural vibration frequency of 10 Hz. The second stage was a set of three beams, disposed between the backpack and the structure that held the SIM optics, that were flexured such that they transmitted only bending loads, with a natural vibrational frequency and damping of about 5 Hz and 4 percent, respectively. Preliminary test results were presented and characterized as demonstrating the effectiveness of the two-stage vibration-isolation design
Freeze casting of porous monolithic composites for hydrogen storage
Hydrogen storage by adsorption offers operational benefits over energy intensive compression techniques. Incorporating physisorption materials in compression stores could improve hydrogen capacities, reducing the volume or pressure needed for storage vessels. However, such materials are often presented as fine powders and development efforts to date have predominantly focused on improving hydrogen uptake alone. Without due attention to industry-relevant attributes, such as handling, processability, and mechanical properties it is unlikely that these materials will find commercial application. In the paper, the desirable mechanical properties of hydrogen-adsorbent PIM-1 are exploited to yield a series of composite monoliths doped with a high surface area activated carbon, intended to act as pressure vessel inserts. Freeze casting techniques were successfully adapted for use with chloroform, facilitating the production of coherent and controlled three-dimensional geometries. This included the use of an innovative elastomeric mould made by additive manufacture to allow facile adoption, with the ability to vary multiple forming factors in the future. The composite monolith formed exhibited a stiffness of 0.26 GPa, a compressive strength of 6.7 MPa, and an increased BET surface area of 847 m2 g−1 compared to PIM-1 powders, signifying the first steps towards producing hydrogen adsorbents in truly useful monolithic forms
Long-term trends in invertebrate-habitat relationships under protected and fished conditions
Few studies examine the long-term effects of changing predator size and abundance on the habitat associations of resident organisms despite that this knowledge is critical to understand the ecosystem effects of fishing. Marine reserves offer the opportunity to determine ecosystem-level effects of manipulated predator densities, while parallel monitoring of adjacent fished areas allows separating these effects from regional-scale change. Relationships between two measures of benthic habitat structure (reef architecture and topographic complexity) and key invertebrate species were followed over 17years at fished and protected subtidal rocky reefs associated with two southern Australian marine reserves. Two commercially harvested species, the southern rock lobster (Jasus edwardsii) and blacklip abalone (Haliotis rubra) were initially weakly associated with habitat structure across all fished and protected sites. The strength of association with habitat for both species increased markedly at protected sites 2years after marine reserve declaration, and then gradually weakened over subsequent years. The increasing size of rock lobster within reserves apparently reduced their dependency on reef shelters as refuges from predation. Rising predation by fish and rock lobster in the reserves corresponded with weakening invertebrate-habitat relationships for H. rubra and sea urchins (Heliocidaris erythrogramma). These results emphasise that animal-habitat relationships are not necessarily stable through time and highlight the value of marine reserves as reference sites. Our work shows that fishery closures to enhance populations of commercially important and keystone species should be in areas with a range of habitat features to accommodate shifting ecological requirements with ontogenesis
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