A Latent Parameter Node-Centric Model for Spatial Networks

Spatial networks, in which nodes and edges are embedded in space, play a vital role in the study of complex systems. For example, many social networks attach geo-location information to each user, allowing the study of not only topological interactions between users, but spatial interactions as well. The defining property of spatial networks is that edge distances are associated with a cost, which may subtly influence the topology of the network. However, the cost function over distance is rarely known, thus developing a model of connections in spatial networks is a difficult task. In this paper, we introduce a novel model for capturing the interaction between spatial effects and network structure. Our approach represents a unique combination of ideas from latent variable statistical models and spatial network modeling. In contrast to previous work, we view the ability to form long/short-distance connections to be dependent on the individual nodes involved. For example, a node's specific surroundings (e.g. network structure and node density) may make it more likely to form a long distance link than other nodes with the same degree. To capture this information, we attach a latent variable to each node which represents a node's spatial reach. These variables are inferred from the network structure using a Markov Chain Monte Carlo algorithm. We experimentally evaluate our proposed model on 4 different types of real-world spatial networks (e.g. transportation, biological, infrastructure, and social). We apply our model to the task of link prediction and achieve up to a 35% improvement over previous approaches in terms of the area under the ROC curve. Additionally, we show that our model is particularly helpful for predicting links between nodes with low degrees. In these cases, we see much larger improvements over previous models

Sources of agricultural growth in India: role of diversification towards high-value crops

"This study examines the sources of crop income growth in Indian agriculture over the 1980s and 1990s. Using a method developed by Minot (2003), the analysis decomposes crop income growth into the contribution of yield increases, area expansion, price increases, and diversification from low-value crops to higher-value crops. The results confirm that at the national level, technology (higher yield) was the main source of crop income growth during 1980s, while rising prices and diversification emerged as the dominant sources of growth in agriculture during 1990s. Diversification towards higher-value crops such as fruits and vegetables accounted for about 27% of crop income growth in the 1980s and 31% in the 1990s. However, these national averages hide substantial regional variation. In the grain-dominated northern and eastern regions, price increases were the most important source of growth during 1990s, while in the southern and western regions crop income growth was led by diversification into higher-value crops. The results reflect the slowing growth of wheat and rice yields in India, as well as the growing importance of diversification into higher-value crops. Restoring the growth in grain yields will require investment in agricultural research and development, while facilitating further diversification involves institutional development to better link small farmers with growing markets for high-value commodities. " Author's AbstractCrops, income growth, Agriculture, Grain production, Agricultural research, Research and development, High value commodities, Crop yields, Prices, High-value crops, Decomposition,

Styles of underplating in the Marin Headlands Terrane, Franciscan Complex, California

This is a pre-copy-editing, author-produced PDF of an article accepted for publication in The Geological Society of America Special Papers following peer review. The definitive publisher-authenticated version: "Regalla, C., Rowe, C., Harrichhausen, N., Tarling, M. and Singh, J., 2018. Styles of underplating in the Marin Headlands Terrane, Franciscan Complex, California. GSA Special Publications no. 534" is available online at: http://rock.geosociety.org/Store/detail.aspx?id=spe534.Geophysical images and structural cross-sections of accretionary wedges are usually aligned orthogonal to the subduction trench axis. These sections often reveal underplated duplexes of subducted oceanic sediment and igneous crust that record trench-normal shortening and wedge thickening facilitated by down-stepping of the décollement. However, this approach may under-recognize trench-parallel strain and the effects of faulting associated with flexure of the downgoing plate. New mapping of a recently exposed transect across a portion of the Marin Headlands terrane, California, USA documents evidence for structural complexity over short spatio-temporal scales within an underplated system. We document the geometry, kinematics, vergence and internal architecture of faults and folds along ~2.5 km of section, and identify six previously unmapped intra-formational imbricate thrusts and thirteen high-angle faults that accommodate shortening and flattening of the underthrust section. Thrust faults occur within nearly every lithology without clear preference for any stratigraphic horizon, and fold vergence varies between imbricate sheets by ~10-40°. In our map area, imbricate bounding thrusts have relatively narrow damage zones (≤5-10 m), sharp, discrete fault cores, and lack veining, in contrast to the wide, highly-veined fault zones previously documented in the Marin Headlands terrane. The spacing of imbricate thrusts combined with paleo-convergence rates indicates relatively rapid generation of new fault surfaces on ~10-100 ka timescales, a process which may contribute to strain hardening and locking within the seismogenic zone. The structural and kinematic complexity documented in the Marin Headlands are an example of the short spatial and temporal scales of heterogeneity that may characterize regions of active underplating. Such features are smaller than the typical spatial resolution of geophysical data from active subduction thrusts, and may not be readily resolved, thus highlighting the need for cross-comparison of geophysical data with field analogues when evaluating the kinematic and mechanical processes of underplating

Heart transplantation: a history lesson of Lazarus

One of the notable advances in modern day medicine is organ transplantation. None more so than the heart. A complex interaction between physiology, surgery and immunology that spanned decades, involving the hard work of many pioneers in their fields. We revisit the contributions of the pioneers as well as marvel at the paradigm shifts in medicine that have made heart transplantation safe and reproducible with in excess of 3000 transplants done yearly today

Heart transplantation: a history lesson of Lazarus

One of the notable advances in modern day medicine is organ transplantation. None more so than the heart. A complex interaction between physiology, surgery and immunology that spanned decades, involving the hard work of many pioneers in their fields. We revisit the contributions of the pioneers as well as marvel at the paradigm shifts in medicine that have made heart transplantation safe and reproducible with in excess of 3000 transplants done yearly today