358,972 research outputs found
Temporal-topological properties of higher-order evolving networks
Human social interactions are typically recorded as time-specific dyadic
interactions, and represented as evolving (temporal) networks, where links are
activated/deactivated over time. However, individuals can interact in groups of
more than two people. Such group interactions can be represented as
higher-order events of an evolving network. Here, we propose methods to
characterize the temporal-topological properties of higher-order events to
compare networks and identify their (dis)similarities. We analyzed 8 real-world
physical contact networks, finding the following: a) Events of different orders
close in time tend to be also close in topology; b) Nodes participating in many
different groups (events) of a given order tend to involve in many different
groups (events) of another order; Thus, individuals tend to be consistently
active or inactive in events across orders; c) Local events that are close in
topology are correlated in time, supporting observation a). Differently, in 5
collaboration networks, observation a) is almost absent; Consistently, no
evident temporal correlation of local events has been observed in collaboration
networks. Such differences between the two classes of networks may be explained
by the fact that physical contacts are proximity based, in contrast to
collaboration networks. Our methods may facilitate the investigation of how
properties of higher-order events affect dynamic processes unfolding on them
and possibly inspire the development of more refined models of higher-order
time-varying networks
Considerations for the design and conduct of human gut microbiota intervention studies relating to foods
With the growing appreciation for the influence of the intestinal microbiota on human health, there is increasing motivation to design and refine interventions to promote favorable shifts in the microbiota and their interactions with the host. Technological advances have improved our understanding and ability to measure this indigenous population and the impact of such interventions. However, the rapid growth and evolution of the field, as well as the diversity of methods used, parameters measured and populations studied, make it difficult to interpret the significance of the findings and translate their outcomes to the wider population. This can prevent comparisons across studies and hinder the drawing of appropriate conclusions. This review outlines considerations to facilitate the design, implementation and interpretation of human gut microbiota intervention studies relating to foods based upon our current understanding of the intestinal microbiota, its functionality and interactions with the human host. This includes parameters associated with study design, eligibility criteria, statistical considerations, characterization of products and the measurement of compliance. Methodologies and markers to assess compositional and functional changes in the microbiota, following interventions are discussed in addition to approaches to assess changes in microbiota-host interactions and host responses. Last, EU legislative aspects in relation to foods and health claims are presented. While it is appreciated that the field of gastrointestinal microbiology is rapidly evolving, such guidance will assist in the design and interpretation of human gut microbiota interventional studies relating to foods.Peer reviewe
Fast filtering and animation of large dynamic networks
Detecting and visualizing what are the most relevant changes in an evolving
network is an open challenge in several domains. We present a fast algorithm
that filters subsets of the strongest nodes and edges representing an evolving
weighted graph and visualize it by either creating a movie, or by streaming it
to an interactive network visualization tool. The algorithm is an approximation
of exponential sliding time-window that scales linearly with the number of
interactions. We compare the algorithm against rectangular and exponential
sliding time-window methods. Our network filtering algorithm: i) captures
persistent trends in the structure of dynamic weighted networks, ii) smoothens
transitions between the snapshots of dynamic network, and iii) uses limited
memory and processor time. The algorithm is publicly available as open-source
software.Comment: 6 figures, 2 table
Mapping Big Data into Knowledge Space with Cognitive Cyber-Infrastructure
Big data research has attracted great attention in science, technology,
industry and society. It is developing with the evolving scientific paradigm,
the fourth industrial revolution, and the transformational innovation of
technologies. However, its nature and fundamental challenge have not been
recognized, and its own methodology has not been formed. This paper explores
and answers the following questions: What is big data? What are the basic
methods for representing, managing and analyzing big data? What is the
relationship between big data and knowledge? Can we find a mapping from big
data into knowledge space? What kind of infrastructure is required to support
not only big data management and analysis but also knowledge discovery, sharing
and management? What is the relationship between big data and science paradigm?
What is the nature and fundamental challenge of big data computing? A
multi-dimensional perspective is presented toward a methodology of big data
computing.Comment: 59 page
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