Monthly Archives: November 2012

Effects of climate and land management on the type and location of vegetation in wetlands (PNAS)

Periodic floods are a normal occurrence in wetlands. To find out how these floods impact niches of different plant species in wetlands, Princeton researchers studied plant species in Everglades National Park (ENP) in Florida. They found that the sizes of the clusters of each species follow a power law probability distribution and that such clusters have well-defined fractal characteristics. They modeled the effect that periodic flooding and neighboring vegetation have on plant clusters. They found that climate and land management have a predictable impact on the type of vegetation and its spatial organization in wetlands. The findings are highly relevant for the management of wetland ecosystems.

R Foti, M Del Jesus, A Rinaldo, and I Rodriguez-Iturbe. Hydroperiod regime controls the organization of plant species in wetlands.
PNAS, November 13, 2012

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The role of breast structure in tumor development (PNAS)

Why do some breast tumors grow aggressively while others grow slowly? In this study, researchers found that the stiffness of the cells in the area around an emerging tumor influences its ability to grow and invade the breast. Using a 3-D fabrication process, the researchers created artificial breast ducts containing normal breast cells and a single tumor cell. They found that regions characterized by stiffness among the normal cells were more likely to give rise to tumors that are aggressive and invasive, while regions that were less stiff gave rise to tumors that are less invasive.

Eline Boghaert, Jason P. Gleghorn, KangAe Lee, Nikolce Gjorevski, Derek C. Radisky, and Celeste M. Nelson. Host epithelial geometry regulates breast cancer
cell invasiveness. Published online before print November 12, 2012, doi: 10.1073/pnas.1118872109 PNAS November 12, 2012

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Fiber optics could monitor health of pipelines in earthquake zones (Structural Health Monitoring)

Earthquakes can damage pipelines with disastrous consequences to the environment and human health. Real-time monitoring of damage to pipelines after an earthquake can be obtained via fiber optic sensors, which are sensitive to strain at every point along their lengths. The sensors are both bonded to the pipeline and embedded in the soil near the pipeline. Two validation tests have now confirmed the ability of the method to reliably detect the location of damage to a pipeline.

Branko Glisic and Yao Yao. Fiber optic method for health assessment of pipelines subjected to earthquake-induced ground movement.  Structural Health Monitoring November 2012 vol. 11 no. 6 696-711 Published online before print August 15, 2012, doi: 10.1177/1475921712455683

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Changes in Greenland ice sheet over space and time (PNAS)

Polar ice sheets are melting and contributing to a global rise in sea-level. This study looked at changes in Greenland’s ice sheet from April 2002 to August 2011 and found that active areas of ice loss were concentrated on the southeastern and northwestern coasts, with ice mass in the center of Greenland steadily increasing over the decade.

Christopher Harig and Frederik J. Simons. Mapping Greenland’s mass loss in space and time. Proceedings of the National Academy of Sciences. Published online before print November 19, 2012, doi: 10.1073/pnas.1206785109

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The implications of “self-boosting” vaccines on herd immunity

Researchers use mathematical models to consider the implications of “self-boosting” vaccines—a class of emerging vaccines that can establish long-term intermittent antigen presentation within a host—on herd immunity.

“Self-boosting vaccines and their implications for herd immunity” by Nimalan Arinaminpathy, et al.
10.1073/pnas.1209683109

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