Scientists build new ‘tree of life’ for placentals, visualize common ancestor
Scientists have reconstructed the common ancestor of placental mammals–an extremely diverse group including animals ranging from rodents to whales to humans–using the world’s largest dataset of both genetic and physical traits. (more…)
The asteroid collision widely thought to have killed the dinosaurs also led to extreme devastation among snake and lizard species, according to new research — including the extinction of a newly identified lizard Yale and Harvard scientists have named Obamadon gracilis.
“The asteroid event is typically thought of as affecting the dinosaurs primarily,” said Nicholas R. Longrich, a postdoctoral associate with Yale’s Department of Geology and Geophysics and lead author of the study. “But it basically cut this broad swath across the entire ecosystem, taking out everything. Snakes and lizards were hit extremely hard.” (more…)
Studies by Berkeley Lab scientists of electron beam quality in laser plasma accelerators include novel tests for slice-energy spread
Part Two: Slicing through the electron beam
Wim Leemans of Berkeley Lab’s Accelerator and Fusion Research Division heads LOASIS, the Laser and Optical Accelerator Systems Integrated Studies, an oasis indeed for students pursuing graduate studies in laser plasma acceleration (LPA). Among the most promising applications of future table-top accelerators are new kinds of light sources, in which their electron beams power free electron lasers.
“If our LPA electron bunches had good enough quality for free electron lasers – and were really only femtoseconds long – we should see a particular kind of radiation called coherent optical transition radiation, or COTR,” Leemans says. “So I assigned my doctoral student Chen Lin, a graduate of Peking University and now a postdoc there, to find it.” (more…)
A UA study has found poverty, water scarcity, food insecurity and interdependence between the United States and Mexico along the border.
The U.S.-Mexico border is the border in the world with the greatest disparity in access to food and water needed for human survival, according to a report commissioned and published by the Southwest Center at the University of Arizona.
An endowment from the Kellogg Foundation and a UA Confluencenter for Creative Inquiry grant supported the study and its focus on assessing transborder food systems to understand water scarcity and food insecurity within the borderlands region.
The report underscores how in the globalized economy, Arizona and the rest of the United States rely on the skilled labor, water, fresh produce, fish, shellfish and livestock originating in northern Mexico; while in Mexico, the population is increasingly dependent upon frozen and processed foods originating in the United States. (more…)
Washington, D.C. — Scientists have long speculated about why there is a large change in the strength of rocks that lie at the boundary between two layers immediately under Earth’s crust: the lithosphere and underlying asthenosphere. Understanding this boundary is central to our knowledge of plate tectonics and thus the formation and evolution of our planet as we know it today. A new technique for observing this transition, particularly in the portion of Earth’s mantle that lies beneath the Pacific Ocean basin, has led Carnegie and NASA Goddard scientist Nick Schmerr to new insight on the origins of the lithosphere and asthenosphere. His work is published March 23 in Science.
The lithosphere-asthenosphere boundary, or LAB, represents the transition from hot, convecting mantle asthenosphere to overlying cold and rigid lithosphere. The oceanic lithosphere thickens as it cools over time, and eventually sinks back into the mantle at Earth’s so-called subduction zones. (more…)
