Dinosaur biogeographic structure and Mesozoic continental fragmentation: a network-based approach

Aim: To reconstruct dinosaur macro-biogeographical patterns through the Mesozoic Era using a network-based approach. We test how continental fragmentation affected dinosaur macro-biogeographical structure and evolutionary rates. Location: A global occurrence database of dinosaur families from the Late Triassic to the end-Cretaceous was used for this study. Methods: Biogeographical and geographical network models were constructed. Continental landmasses were linked by direct continental contact and sea level (SL)-conditioned connections in geographical networks, and by shared dinosaur families in biogeographical networks. Biogeographical networks were run with raw, novel and first-step connections for all dinosaur, ornithischian, theropod, and sauropodomorph taxa. Results: Geographical connectedness declines through time, from peak aggregation in the Triassic–Jurassic to complete separation in the latest Cretaceous. Biogeographical connectedness shows no common trend in the raw and novel connection network models, but decreases through time while showing some correlation with continental fragmentation in most of the first-step network models. Despite continental isolation and high SLs, intercontinental faunal exchange continued right up to the end of the Cretaceous. Continental fragmentation and dinosaurian macro-biogeographical structure do not share a common pattern with dinosaurian evolutionary rates, although there is evidence that increased continental isolation resulted in increased origination rates in some dinosaurian lineages. Spatiotemporal sampling biases and early Mesozoic establishment of family-level distribution patterns are important drivers of apparent dinosaur macro-biogeographical structure. Main conclusions: There is some evidence to suggest that dinosaur macro-biogeographical structure was influenced by continental fragmentation, although intercontinental exchange of dinosaur faunas appears to have continued up to the end of the Cretaceous. Macro-biogeographical patterns are obscured by uneven geographical sampling through time and a residual earlier Mesozoic distribution which is sustained up to the end of the Cretaceous

Understanding the implementation of evidence-based care: A structural network approach

<p>Abstract</p> <p>Background</p> <p>Recent study of complex networks has yielded many new insights into phenomenon such as social networks, the internet, and sexually transmitted infections. The purpose of this analysis is to examine the properties of a network created by the 'co-care' of patients within one region of the Veterans Health Affairs.</p> <p>Methods</p> <p>Data were obtained for all outpatient visits from 1 October 2006 to 30 September 2008 within one large Veterans Integrated Service Network. Types of physician within each clinic were nodes connected by shared patients, with a weighted link representing the number of shared patients between each connected pair. Network metrics calculated included edge weights, node degree, node strength, node coreness, and node betweenness. Log-log plots were used to examine the distribution of these metrics. Sizes of k-core networks were also computed under multiple conditions of node removal.</p> <p>Results</p> <p>There were 4,310,465 encounters by 266,710 shared patients between 722 provider types (nodes) across 41 stations or clinics resulting in 34,390 edges. The number of other nodes to which primary care provider nodes have a connection (172.7) is 42% greater than that of general surgeons and two and one-half times as high as cardiology. The log-log plot of the edge weight distribution appears to be linear in nature, revealing a 'scale-free' characteristic of the network, while the distributions of node degree and node strength are less so. The analysis of the k-core network sizes under increasing removal of primary care nodes shows that about 10 most connected primary care nodes play a critical role in keeping the <it>k</it>-core networks connected, because their removal disintegrates the highest <it>k</it>-core network.</p> <p>Conclusions</p> <p>Delivery of healthcare in a large healthcare system such as that of the US Department of Veterans Affairs (VA) can be represented as a complex network. This network consists of highly connected provider nodes that serve as 'hubs' within the network, and demonstrates some 'scale-free' properties. By using currently available tools to explore its topology, we can explore how the underlying connectivity of such a system affects the behavior of providers, and perhaps leverage that understanding to improve quality and outcomes of care.</p

International home economics

The conference was planned to serve the interests of those who wish to work in home economics programs abroad and those who are concerned with the education of international students in the universities and colleges of the United States. Approximately 165 home economists from other states and from foreign countries I including the African and Latin American countries I participated in the conference.https://lib.dr.iastate.edu/card_reports/1026/thumbnail.jp

On the Dynamics of the Spontaneous Activity in Neuronal Networks

Most neuronal networks, even in the absence of external stimuli, produce spontaneous bursts of spikes separated by periods of reduced activity. The origin and functional role of these neuronal events are still unclear. The present work shows that the spontaneous activity of two very different networks, intact leech ganglia and dissociated cultures of rat hippocampal neurons, share several features. Indeed, in both networks: i) the inter-spike intervals distribution of the spontaneous firing of single neurons is either regular or periodic or bursting, with the fraction of bursting neurons depending on the network activity; ii) bursts of spontaneous spikes have the same broad distributions of size and duration; iii) the degree of correlated activity increases with the bin width, and the power spectrum of the network firing rate has a 1/f behavior at low frequencies, indicating the existence of long-range temporal correlations; iv) the activity of excitatory synaptic pathways mediated by NMDA receptors is necessary for the onset of the long-range correlations and for the presence of large bursts; v) blockage of inhibitory synaptic pathways mediated by GABA(A) receptors causes instead an increase in the correlation among neurons and leads to a burst distribution composed only of very small and very large bursts. These results suggest that the spontaneous electrical activity in neuronal networks with different architectures and functions can have very similar properties and common dynamics

Historicising Material Agency: from Relations to Relational Constellations

Relational approaches have gradually been changing the face of archaeology over the last decade: analytically, through formal network analysis; and interpretively, with various frameworks of human-thing relations. Their popularity has been such, however, that it threatens to undermine their relevance. If everyone agrees that we should understand past worlds by tracing relations, then ‘finding relations’ in the past becomes a self-fulfilling prophecy. Focusing primarily on the interpretive approaches of material culture studies, this article proposes to counter the threat of irrelevance by not just tracing human-thing relations, but characterising how sets of relations were ordered. Such ordered sets are termed ‘relational constellations’. The article describes three relational constellations and their consequences based on practices of fine ware production in the Western Roman provinces (first century BC – third century AD): the fluid, the categorical, and the rooted constellation. Specifying relational constellations allows reconnecting material culture to specific historical trajectories, and offers scope for meaningful cross-cultural comparisons. As such a small theoretical addition based on the existing toolbox of practice-based approaches and relational thought can impact on historical narratives, and can save relational frameworks from the danger of triviality.This is the author accepted manuscript. The final version is available from Springer via http://dx.doi.org/10.1007/s10816-015-9244-

Butts, R. Freeman, The Progressive Malaise of Revisionist Historians--As Seen by a Progressive, pp. 23-28 in Laurel N. Tanner, ed., Papers of the Society for the Study of Curriculum History. University Park, PA: The Society, College of Education, Penn State University, 1981.

Argues against revisionist historians\u27 views of education and its treatment of progressive educaiton

A cultural history of Western education; its social and intellectual foundations

xii, 645 p.; 23 c

A history of education in American culture

xii, 628 hal.; 24 cm