Raindrop study implies incorrect forecasts
HOUGHTON, Mich., June 11 (UPI) -- U.S. and Mexican physicists have found smaller raindrops can fall faster than bigger ones, meaning some weather forecasters have overestimated rainfall.
Scientists from Michigan Technological University and the National University of Mexico said it's been conventional atmospheric science wisdom that large raindrops fall faster than smaller drops, because they're bigger and heavier. And no raindrop can fall faster than its "terminal speed" -- its speed when the downward force of gravity is exactly the same as the upward air resistance.
But in the new research scientists discovered some smaller drops not only can fall faster than bigger ones, but they can fall faster than their terminal speed -- in other words, they can fall faster than drops of that size and weight are supposed to be able to fall.
The researchers -- Michigan Tech Professors Alexander Kostinski and Raymond Shaw with Guillermo Montero-Martinez and Fernando Garcia-Garcia in Mexico -- said the findings could significantly alter scientists' understanding of the physics of rain and improve the accuracy of weather measurements and forecasts.
The study is reported in the June 13 issue of the journal Geophysical Research Letters.
Swine flu development timescale analyzed
EDINBURGH, Scotland, June 11 (UPI) -- U.S., Chinese and British researchers say the H1N1 swine flu virus was transmitted to humans long before the existing outbreak was noticed.
The scientists said their analysis of the current swine-origin H1N1 influenza outbreak -- declared a pandemic Thursday by the World Health Organization -- calls for the need of systematic surveillance of influenza in swine, and provides evidence that new genetic elements in swine can result in the emergence of viruses with pandemic potential in humans.
Andrew Rambaut of the Institute of Evolutionary Biology at the University of Edinburgh in Scotland and colleagues estimated the timescale of the development of the epidemic. They determined it was derived from several swine viruses and the initial transmission to humans occurred several months before recognition of the outbreak.
"Despite widespread influenza surveillance in humans, the lack of systematic swine surveillance allowed for the undetected persistence and evolution of this potentially pandemic strain for many years," the researchers said.
The study that included scientists from the University of Hong Kong, the University of Arizona in the United States and Oxford University in Britain appears in the early online edition of the journal Nature.
Interconnected carbon nanostructures made
PHILADELPHIA, June 11 (UPI) -- U.S. scientists have formed interconnected carbon nanostructures on graphene substrates in a study that might lead to new carbon-based devices.
The researchers from the University of Pennsylvania, Sandia National Laboratories and Rice University said the simple assembly process involves heating few-layer graphene sheets to sublimation using electric current.
Curvy nanostructures such as carbon nanotubes and fullerenes have extraordinary properties, the scientists said, but are extremely challenging to pick up, handle and assemble into devices after synthesis.
Penn Associate Professor Ju Li and Sandia scientist Jianyu Huang, the study's co-leaders, developed an idea to construct curvy nanostructures directly integrated on graphene, since the atomically thin two-dimensional sheet bends easily with open edges that can then permanently fuse with other open edges.
The experiments were performed inside an electron microscope using electrical current generating up to 2000 degrees Celsius heat.
"This study demonstrates it is possible to make and integrate curved nanostructures directly on flat graphene, which is extended and electrically conducting," said Li. "Furthermore, it demonstrates that multiple graphene sheets can be intentionally interconnected."
The research that included Liang Qi at the University of Pennsylvania, Ping Lu at Sandia and Feng Ding and Boris Yakobson at Rice is reported in the Proceedings of the National Academy of Sciences.
Protein may predict cancer drug resistance
ROTTERDAM, Netherlands, June 11 (UPI) -- Dutch and U.S. medical researchers have discovered a protein profile that may predict whether a breast cancer patient will be resistant to tamoxifen therapy.
Tamoxifen is a widely used and effective drug designed to treat breast cancer. But the scientists said resistance to tamoxifen is problematic in recurrent disease that affects 25 percent to 35 percent of patients because therapy resistant metastatic tumor cells are a major cause of death.
In the new study, Arzu Umar of the Erasmus University Medical Center and colleagues in the Netherlands and Washington examined thousands of tumor cells taken from 51 tamoxifen therapy-sensitive and therapy-resistant tumors. Using a combination of proteomic and mass-spectrometry approaches they identified a set of 100 proteins expressed at different abundance levels in the two tumor groups, highlighting a potential profile for tamoxifen resistance.
While further work with additional samples will be needed, the researchers said the profile could be clinically useful, especially considering their approach used minute amounts of tissue samples, making it applicable at even the earliest tumor stages.
The research is detailed in the journal Molecular and Cellular Proteomics.
