bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantification of microRNA Expression with Next‐Generation Sequencing
Authors: Eminaga Seda , Christodoulou Danos C. , Vigneault Francois , Church George M. , Seidman J.G.
Published: July 2013

Rapid advancement of next‐generation sequencing technologies has made it possible to study expression profiles of microRNAs (miRNAs) comprehensively and efficiently. Multiplexing miRNA libraries by barcoding can significantly reduce sequencing cost per sample without compromising library quality. This unit provides a step‐by‐step protocol for isolating miRNAs and constructing multiplexed miRNA libraries. Also described is a custom computational pipeline for analyzing the multiplexed miRNA library sequencing reads generated by Illumina‐based technology. Curr. Protoc. Mol. Biol. 103:4.17.1–4.17.14. © 2013 by John Wiley & Sons, Inc.
What Is Climate?
Authors: Lovejoy S.
Published: July 2013

Most people have an intuitive understanding of the weather as referring to the state of the atmosphere at a given time and place and of the climate as a kind of average weather. A popular expression of this dichotomy is “the climate is what you expect, the weather is what you get” (Heinlein [1973, p. 352], although often attributed to Mark Twain). Implicit in this belief is the notion of climate as a kind of constant natural state to which the weather would converge if it were averaged over a long enough period. A corollary is that climate change is a consequence of “climate forcings,” which are external to the natural climate system and which tend to prevent averages from converging to their true values. In this framework, past climate change may be attributed to orbital changes, variations in solar output, volcanic eruptions, etc. For the recent period, anthropogenic forcings can be added.
Consequences of early snowmelt in Rocky Mountains
Authors: Balcerak Ernie
Published: July 2013

Snow melted significantly earlier in the Rocky Mountains in 2012 than in previous years, with serious consequences for plants and animals, scientists reported at the AGU Fall Meeting. David Inouye of the University of Maryland, College Park, and the Rocky Mountain Biological Laboratory said that “the timing of winter's end is changing.” He has been observing snowmelt dates and flowering of plants at a site at 2900 meters altitude. This year's snowmelt occurred 23 April, whereas the previous year, snow melted 19 June, he reported.
The Floodgates of Change
Authors: McPhaden Michael J.
Published: July 2013

It has been a great honor to serve as president and, for 2 years before that, as president‐elect of AGU. I was drawn to AGU more than 30 years ago as a graduate student because it was an exciting and supportive organization of scientists working together to solve big problems to make the world a better place. My first AGU Fall Meeting left an indelible impression, reinforced every year since: a weeklong celebration of science—sharing, learning, and discovering—amid a sea of exuberant participants from around the globe. In AGU I found a community that nurtured my professional development and provided me with exceptional opportunities for career advancement. So when I was asked to run for president, it was an easy decision. I welcomed the chance to give back to the organization that had contributed so much to my growth as a scientist.
Bowen, Dufek, and Shelly Receive 2012 James B. Macelwane Medals: Citation
Authors: Hardbeck Jeanne , Hill David
Published: July 2013

David R. Shelly is awarded the 2012 Macelwane Medal for his revolutionary advances in understanding the nature of tectonic tremor and its role in the earthquake preparation process. His innovations in the study of this subtle “noise” from deep within the Earth has opened a new window into the processes governing the earthquake cycle on major plate boundary faults and the magmatic systems beneath active volcanoes.
David E. Smith Receives 2012 Charles A. Whitten Medal: Citation
Authors: Phillips Roger J.
Published: July 2013

David E. Smith was awarded the 2012 Charles A. Whitten Medal at the AGU Fall Meeting Honors Ceremony, held on 5 December 2012 in San Francisco, Calif. The medal is for “outstanding achievement in research on the form and dynamics of the Earth and planets.”
Call for tighter coal ash disposal standards
Authors: Showstack Randy
Published: July 2013

More than 200 million tons of coal ash and scrubber sludge were deposited from coal plants into ponds or landfills between 2009 and 2011, according to a 21 December report by the Environmental Integrity Project (EIP), a nonprofit organization based in Washington, D. C. EIP issued the report to mark the fourth anniversary of the dike rupture at the Tennessee Valley Authority's Kingston Fossil Plant, which spilled an estimated 1.1 billion gallons of coal fly ash slurry into the Tennessee River system on 22 December 2008. EIP called for the U.S. Environmental Protection Agency (EPA) to issue ash disposal standards.
Fire activity increasing as climate changes
Authors: Balcerak Ernie , Showstack Randy
Published: July 2013

Analysis of images from NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) satellites shows that more than 2.5 million hectares were burned in 2012 from January through August in the United States. The amount is less than a record 3.2 million hectares in 2011 but greater than the area burned in 12 of 15 years since satellite monitoring began, scientists reported at the AGU Fall Meeting. With satellites “we can detect fires as they're actively burning,” said Louis Giglio of the University of Maryland, College Park, at a press conference on 4 December. “We can also map the cumulative area burned on the landscape after the fire's over.” He noted that “2012 has been a particularly big fire year” in the United States.
The Evolution of the Lunar Highlands Crust: A Complicated History
Authors: Klima Rachel
Published: July 2013

More than 30 years after the first Lunar Highlands Crust conference, lunar petrology and remote sensing experts from around the world gathered to discuss and debate the formation and evolution of the lunar highlands crust. Huge strides in orbital remote sensing have enabled researchers to put the samples gathered during the Apollo missions into a larger, global context, yet many of the original, key questions remain. What was the extent and fate of the lunar magma ocean (LMO)? What is the nature of the lower lunar crust? Do lunar sample ages still suggest that the inner solar system was subject to an increase in impact flux around 3.9 billion years ago? At the heart of these questions is the desire to understand not only the formation and evolution of the Moon but of Earth, the terrestrial planets, and the inner solar system as a whole.
Soft electron precipitation explains thermosphere mass enhancements
Authors: Balcerak Ernie , Schultz Colin
Published: July 2013

From 2000 to 2010, a German satellite carrying the Challenging Minisatellite Payload (CHAMP) orbited the Earth, tracking the properties of the thermosphere—the atmospheric layer that starts roughly 90 kilometers above the surface and coincides with the lower layers of the ionosphere. In analyzing CHAMP's observations, researchers came across an anomaly: 400 kilometers above the Earth in two different regions in the thermosphere, the density was persistently higher than scientists expected given model calculations. The density enhancements were found in two places: at the dayside cusp—the polar region where terrestrial magnetic field lines create a funnel for the solar wind—and in the auroral region on the planet's nightside. Though researchers had identified these anomalous regions, they have so far been unable to identify a mechanism to explain them.
Geologic Exploration of the Planets: The First 50 Years
Authors: Carr Michael H.
Published: July 2013

Fifty years ago, on 14 December 1962, the Mariner 2 spacecraft flew by Venus and inaugurated the modern era of planetary exploration. Since that first Venus flyby, roughly 80 spacecraft have successfully probed, orbited, flown by, landed on, or roved on other planets, satellites, asteroids, and comets. As Carl Sagan used to say, only one generation of humankind can be the first explorers of the solar system, and we are that generation.
Robert Cooper Liebermann Receives 2012 Edward A. Flinn III Award: Response
Authors: Liebermann Robert Cooper
Published: July 2013

Thank you, Mr. President; I thank AGU for this high honor.
Faisal Hossain Receives 2012 Charles S. Falkenberg Award: Citation
Authors: Anagnostou Emmanouil , Borga Marco , Mahbubur Rahman S. M. , Shum C. K.
Published: July 2013

Faisal Hossain received the 2012 Charles S. Falkenberg Award at the AGU Fall Meeting Honors Ceremony, held on 5 December 2012 in San Francisco, Calif. The award honors a “scientist under 45 years of age who has contributed to the quality of life, economic opportunities, and stewardship of the planet through the use of Earth science information and to the public awareness of the importance of understanding our planet.
John R. Delaney Receives 2012 Athelstan Spilhaus Award: Citation
Authors: Leinen Margaret
Published: July 2013

John R. Delaney received the Athelstan Spilhaus Award at the 2012 AGU Fall Meeting Honors Ceremony, held on 5 December 2012 in San Francisco, Calif. The award honors “individuals who have devoted portions of their lives to expressing the excitement, significance, and beauty of the Earth and space sciences to the general public.”
Steven Mufson, Brian Vastag, and The Washington Post Graphics Staff Receive 2012 David Perlman Award for Excellence in Science Journalism–News: Citation
Authors: Townsend Claudia
Published: July 2013

Steven Mufson and Brian Vastag, staff writers for The Washington Post, and The Washington Post Graphics Staff received the David Perlman Award for Excellence in Science Journalism–News at the AGU Fall Meeting Honors Ceremony, held on 5 December 2012 in San Francisco, Calif. Mufson and Vastag were honored for the article “For Virginia's fault zone, an event of rare magnitude,” published 23 August 2011 (online initially). The article covers the unusual 5.8 magnitude earthquake that shook up the Washington, D. C., region on that day, providing broad and insightful scientific perspective on the event immediately after it occurred . The Post Graphics Staff created an eye‐catching, colorful, and informative illustration that accompanied and enhanced the article. The Perlman award is for work published with a deadline pressure of 1 week or less.
Clouds could explain how Snowball Earth thawed out
Authors: Schultz Colin
Published: July 2013

Glaciation events during the Neoproterozoic (524–1,000 million years ago) and Paleoproterozoic (1,600–2,500 million years ago) periods—events that spawned ice ages that persisted for millions of years at a time—may have seen glacier ice encircle the planet in a frosty planetary configuration known as a Snowball Earth. Whether the planet could have existed in such a state, however, is a matter of considerable debate.
Scientists Debate Whether the Anthropocene Should Be a New Geological Epoch
Authors: Showstack Randy
Published: July 2013

By about 2017 or 2018, scientists probably will have determined whether or not the Earth has entered into the “Anthropocene” epoch. Although many people are convinced that we are already living in the Anthropocene, that's the estimate for when a scientific review process could culminate in officially designating this potential new epoch of the Quaternary Period (roughly the past 2.6 million years) signified by profound human alteration to geological conditions and processes. The epoch would encompass—for the time being—a sliver of geological time separate rom the Holocene (roughly 12,000 years ago to the present), starting from perhaps the beginning of the Industrial Revolution, the end of World War II, or some other date determined to be a good marker to designate the beginning of the Anthropocene.
Landsat continuity mission set for launch
Authors: Showstack Randy
Published: July 2013

While the Landsat Data Continuity Mission (LDCM), scheduled for launch on 11 February, is expected to continue Landsat's more than 40‐year continuous record of providing Earth surface data, the future of the program beyond that mission—which will be renamed as Landsat 8 after its initial space checkout phase—is unclear, according to an official with the U.S. Geological Survey (USGS).
Highlights of 2012 Fall Meeting
Authors: Finn Carol
Published: July 2013

This past December the streets of San Francisco, Calif., surrounding the Moscone Center were awash with a sea of Earth and space scientists attending the 45th consecutive AGU Fall Meeting, eager to share and expand their knowledge “for the benefit of humanity.” As it has for many years, attendance at AGU's Fall Meeting—the largest gathering of Earth and space scientists in the world—continued to increase, this year passing the 24,000 mark. Attendees at the meeting, which took place on 3–7 December 2012, hailed from 97 countries; nearly 7000 of them were students. News from the Fall Meeting was carried in newspapers and on Web sites around the world, and the social media sphere lit up with talk of AGU and the Fall Meeting. It's even reported that for a short time we were a trending topic on Twitter.
Fall Meeting by the Numbers
Authors: Ward Joanna
Published: July 2013

The 2012 Fall Meeting achieved many new successes, from advances in technology to presentations of exciting science. Attendance has once again grown, with more than 24,000 scientists, researchers, students, teachers, exhibitors, media, and guests convening in San Francisco to experience the week‐long activities and workshops, including 6894 oral and 13,790 poster presentations, 5 general sessions, an exhibit hall with more than 270 exhibitors, more than 50 section and focus group social events and committee meetings, and 55 town hall meetings.
AGU Honors 82 Geophysicists
Authors: Paredes Beth
Published: July 2013

This year's Honors Ceremony, held on 5 December 2012, celebrated 82 AGU geophysicists for their profound contributions and breakthrough achievements. These outstanding scientists were honored for their persistence, dedication, pursuit of excellence, and scientific statesmanship. Their work continues to advance science and to communicate it better; it inspires and guides the scientific community as they seek to expand and deepen knowledge for the benefit of humanity.
Scientists Share Their Work With K–12 Teachers at Geophysical Information for Teachers Workshop
Authors: Adamec Bethany Holm , Johnson Roberta
Published: July 2013

For the second year in a row, the AGU Education staff partnered with the National Earth Science Teachers Association (NESTA) to hold the annual Geophysical Information for Teachers (GIFT) workshop at AGU's annual Fall Meeting.
Career Center Hosts a Variety of Events
Authors: Cooper Paul
Published: July 2013

Record numbers of 2012 AGU Fall Meeting attendees participated in an unprecedented number of career development and guidance events. The AGU Career Services section put together a diverse program of 26 events, from informal talks in the Career Lounge to career guidance workshops and networking opportunities.
Transforming the 2012 Fall Meeting Experience Through Technology
Authors: Mickelson Kerry
Published: July 2013

The 2012 Fall Meeting continued building on AGU's commitment to transform the meeting experience through technology.
Former U.S. Geological Survey Director McNutt Discusses Highlights and Challenges
Authors: Showstack Randy
Published: July 2013

Marcia McNutt, who served as director of the U.S. Geological Survey (USGS) and science advisor to the secretary of the Department of the Interior (DOI) since November 2009, left office on 15 February 2013, a few days after the successful launch of the Landsat 8 Earth imaging satellite and shortly before potential automatic and across‐the‐board federal budget cuts, known as “sequestration,” were due to be implemented. McNutt said that sequestration, which currently is scheduled for 1 March, “could be devastating” for USGS.
Parts of Antarctica's King George Island are littered with trash
Authors: Kumar Mohi
Published: July 2013

A report released 7 February by ecologists from Germany's Friedrich Schiller University Jena reveals that parts of King George Island, a logistical hub for international research in Antarctica, are home to open pits of trash, decaying field huts, and other forms of pollution.
Free “Cook Book” for gridding bathymetric data
Authors: Kumar Mohi
Published: July 2013

The International Hydrographic Organization (IHO) and the General Bathymetric Chart of the Oceans (GEBCO) program of the United Nations Educational, Scientific and Cultural Organization's Intergovernmental Oceanographic Commission (UNESCO IOC) have created a free manual to help users prepare quality bathymetric grids from available data points. The new “IHO‐IOC GEBCO Cook Book,” released last year and available at http://www.gebco.net, provides step‐by‐step instructions, screenshots, command lines, and snippets of code applied on actual data, to guide users through the process of gridding data.
Toward a Comprehensive Understanding of Land‐Atmosphere Interactions at Multiple Scales
Authors: Jiménez Pedro A. , de Arellano J. Vilá‐Guerau , Navarro J.
Published: July 2013

There is an increasing awareness of the major influence that land‐atmosphere interactions (L‐AI) have on weather and climate at local and regional scales. Scientists’ understanding of the physical processes governing the interactions between atmospheric dynamics and land surface processes is still limited, which hampers improvement in model parameterizations.
Working With Strainmeter Data
Authors: Hodgkinson Kathleen , Agnew Duncan , Roeloffs Evelyn
Published: July 2013

The Plate Boundary Observatory (PBO), the geodetic component of the U.S. National Science Foundation–funded Earthscope program, includes 75 borehole and 6 laser strainmeters (http://pbo.unavco.org). The strainmeters are installed at several locations: on the Cascadia forearc in Washington state and on Vancouver Island, Canada; in arrays of two to nine instruments along the North American–Pacific plate boundary in California; at Mount St. Helens; and in Yellowstone National Park. For deformation signals seconds to weeks in duration, strainmeters have a resolution and a signal‐to‐noise ratio superior to those of seismometers and GPS. However, this high sensitivity can introduce nontectonic signals into strain data, presenting data interpretation challenges, especially for borehole strainmeters.
Aftershocks to Philippine quake found within nearby megathrust fault
Authors: Schultz Colin
Published: July 2013

On 31 August 2012 a magnitude 7.6 earthquake ruptured deep beneath the sea floor of the Philippine Trench, a powerful intraplate earthquake centered seaward of the plate boundary. In the wake of the main shock, sensors detected a flurry of aftershocks, counting 110 in total. Drawing on seismic wave observations and rupture mechanisms calculated for the aftershocks, Ye et al. found that many were located near the epicenter of the main intraplate quake but at shallower depth; all involved normal faulting. Some shallow thrusting aftershocks were located farther to the west, centered within the potentially dangerous megathrust fault formed by the subduction of the Philippine Sea plate beneath the Philippine microplate, the piece of crust housing the Philippine Islands.
High‐Resolution Satellite Data Open for Government Research
Authors: Neigh Christopher S. R. , Masek Jeffrey G. , Nickeson Jaime E.
Published: July 2013

U.S. satellite commercial imagery (CI) with resolution less than 1 meter is a common geospatial reference used by the public through Web applications, mobile devices, and the news media. However, CI use in the scientific community has not kept pace, even though those who are performing U.S. government research have access to these data at no cost. Previously, studies using multiple CI acquisitions from IKONOS‐2, Quickbird‐2, GeoEye‐1, WorldView‐1, and WorldView‐2 would have been cost prohibitive. Now, with near‐global submeter coverage and online distribution, opportunities abound for future scientific studies. This archive is already quite extensive (examples are shown in Figure 1) and is being used in many novel applications.
Validating Satellite‐Derived Vegetation Phenology Products
Authors: Dash Jadu , Jones Matthew , Nightingale Joanne
Published: July 2013

The phenology of terrestrial vegetation, i.e., the timing of events such as bud burst, leaf development, and senescence, plays an important role in the global climate system, biogeochemical cycles, and energy budget. Satellite‐derived vegetation indices have long been used as proxies for representing the status of terrestrial vegetation, and hence, the time series of these data sets were used to derive key land surface phenological variables such as the start and end of the growing season. Despite an increase in effort toward characterization of vegetation phenology from satellite data, its validation with ground measurements is still challenging because of mismatches in both spatial and temporal scales between the two types of measurements, distribution of ground measurements, and spatial heterogeneity of vegetation types in a satellite sensor pixel.
A geostatistical approach to downscaling climate forecasts
Authors: Schultz Colin
Published: July 2013

Though global general circulation models are the tool of choice for forecasting the effects of climate change, their spatial resolutions are too broad for the needs of regional planners. To provide locally relevant information, modelers typically employ one of two techniques: producing a new forecast using a regional dynamic model or statistically downscaling the projections of the larger model. As a subset of the statistical approach, Jha et al. propose a geostatistical technique to translate climate‐modeling results to a smaller spatial scale.
Freshwater storage declining in Middle East
Authors: Balcerak Ernie
Published: July 2013

Freshwater storage in the Middle East is declining at an alarming rate, according to a new study by Voss et al. The Middle East has limited water resources, and conflicts over existing water resources are already occurring. However, there are few publicly available data sources on water resources in the Middle East.
Tracing the origin of Arctic driftwood
Authors: Balcerak Ernie
Published: July 2013

Tracking the origin of driftwood samples could help scientists to reconstruct past currents in the Arctic Ocean, a new study suggests. Arctic currents are likely to be affected by changing climate, but there are few observations that provide evidence on past ocean current dynamics.
Very short‐lived halocarbons over the tropical Atlantic
Authors: Balcerak Ernie
Published: July 2013

Very short lived halocarbons (VSLH), including CHBr3, CH2Br2, CHCl3, C2H5I, and CH2ClI, can be transported upward through the atmosphere from the marine boundary layer and contribute to ozone depletion—as far up as the lower stratosphere in the case of brominated and chlorinated compounds. VSLH are released from algae, marine bacteria, and photochemical breakdown of organic material in the ocean, but there are uncertainties in the contributions from these sources, and global distributions are not well known because there are wide spatial variations in fluxes of VSLH from sea to air.
A window into the interior of asteroid Vesta
Authors: Balcerak Ernie
Published: July 2013

On the asteroid Vesta, a large, deep impact basin, called Rheasilvia, exposes the mantle below the asteroid's crust, providing a window into Vesta's interior. The impact that formed the basin is thought to have kicked out pieces of Vesta to form the Vestoids, smaller asteroids whose orbits suggest that they originated from Vesta. The Vestoids may be the parent bodies of the howardite‐eucrite‐diogenite (HED) meteorites.
Coupled model isolates effect of lower atmosphere on ionosphere
Authors: Schultz Colin
Published: July 2013

Day‐to‐day variability in the properties and behavior of the ionosphere, a region of the upper atmosphere, is driven by three main forces: shifts in the solar wind, changes in the Earth's geomagnetic field, and the downstream effects of variability in lower atmospheric layers. According to previous research, ionospheric variability driven by atmospheric process and by geomagnetic fluctuations are roughly equivalent in scale. Attempts to accurately model the effect of lower atmospheric dynamics on the ionosphere, however, have generally been limited by the low temporal resolution of the data used to represent the interactions.
Proposed Department of Energy Budget Increases Support for Renewable Energy
Authors: Balcerak Ernie
Published: July 2013

In the Obama administration's proposed budget for fiscal year (FY) 2014, the Department of Energy (DOE) would get a total of $28.4 billion, up from $26.3 billion in FY 2012, an 8% increase (comparisons are to FY 2012 because final appropriations for 2013 were not available when the president released his proposed FY 2014 budget).
Beyond Hammers and Nails: Mitigating and Verifying Greenhouse Gas Emissions
Authors: Gurney Kevin Robert
Published: July 2013

One of the biggest challenges to future international agreements on climate change is an independent, science‐driven method of verifying reductions in greenhouse gas emissions (GHG) [Niederberger and Kimble, 2011]. The scientific community has thus far emphasized atmospheric measurements to assess changes in emissions. An alternative is direct measurement or estimation of fluxes at the source. Given the many challenges facing the approach that uses “top‐down” atmospheric measurements and recent advances in “bottom‐up” estimation methods, I challenge the current doctrine, which has the atmospheric measurement approach “validating” bottom‐up, “good‐faith” emissions estimation [Balter, 2012] or which holds that the use of bottom‐up estimation is like “dieting without weighing oneself” [Nisbet and Weiss, 2010].
Are element ratios in coral cores a good proxy for past temperature?
Authors: Balcerak Ernie
Published: July 2013

Strontium‐to‐calcium ratios (Sr/Ca) in cores from coral skeletons are widely used as a proxy for past temperature (Sr/Ca has a negative relationship with temperature—this ratio typically declines as temperatures rise). As corals grow, they build aragonite (CaCO3) skeletons, and minor chemical elements are incorporated into those skeletons at different proportions depending on conditions such as temperature. However, those elemental ratios can also be affected by biological factors in the individual coral, including an individual coral's growth rate. This makes the use of coral Sr/Ca ratios as a paleothermometer potentially problematic.
Nonnative salmon alter nitrification in Great Lakes tributaries
Authors: Balcerak Ernie
Published: July 2013

Nonnative species can affect the biogeochemistry of an ecosystem. For instance, Pacific salmon have been introduced for sport fishing in many streams and lakes beyond their native range, and their introduction may be altering nitrogen cycling in those ecosystems.
Plasma injection events in Saturn's magnetosphere
Authors: Balcerak Ernie
Published: July 2013

Periodic radio emissions, including the strong radio emissions known as the Saturn kilometric radio (SKR) emissions, originate from the northern and southern polar regions and are observed throughout Saturn's magnetosphere. Scientists have been studying these phenomena but have not been able to pin down the physical mechanism linking periodicities between the inner and outer magnetospheres.
Computer‐modeled global census finds thousands of eddies each year
Authors: Kumar Mohi
Published: July 2013

Eddies, the curls and swirls that spin off swift‐moving ocean currents, help disperse energy and nutrients throughout the world's oceans. Floats and other engineered submersibles can help scientists understand the evolution and path of specific eddies. But knowledge of how many eddies exist, as well as how pervasive, how strong, and how large these eddies are at any given moment, would require continuous and detailed monitoring of the entire ocean at all depths—an impossible feat.
Scientists observe near‐inertial wave trapped in Gulf Stream eddy
Authors: Schultz Colin
Published: July 2013

During a research cruise in September 2009, Joyce et al. detected for the first time the existence of a near‐inertial wave trapped within most of a 90 kilometer‐diameter warm‐core eddy in the Gulf Stream. Just as oceanic gravitational waves are driven by the counterbalancing forces of gravity and buoyancy, inertial waves are driven by the wind and the inertial Coriolis force. The downward propagating wave that the authors detected was bounded by the clockwise‐rotating eddy.
Experts Caution About Potential Increased Risks From Space Weather
Authors: Showstack Randy
Published: July 2013

The backdrop for a 4 June Space Weather Enterprise Forum included a May 2013 report by the insurance company Lloyd's, “Solar storm risk to the North American electric grid,” which warns that a geomagnetic storm similar to a strong event in 1859 (the Carrington Event, named after British astronomer Richard Carrington, who observed it) could put 20–40 million Americans at risk of a power outage that could extend from a few days to several years, with enormous societal and economic impacts.
Collisions of coronal mass ejections can be superelastic
Authors: Balcerak Ernie
Published: July 2013

Coronal mass ejections (CMEs), emissions of magnetized ionized gas from the Sun, can damage satellites and communication technology, so being able to predict where they are heading and how much energy they have is important in protecting this technology.
New details on transition zone below western United States
Authors: Balcerak Ernie
Published: July 2013

At certain depths in Earth's mantle, increased pressures cause minerals to undergo phase changes, transforming to different crystal structures. Seismic waves change speed at these discontinuities, so analyzing seismic waves at various depths gives scientists information about the structure of the mantle.
Promoting Climate Science in K–12 Education: An Interview With Eugenie Scott
Authors: Balcerak Ernie
Published: July 2013

Over the course of 26 years at the National Center for Science Education (NCSE), Eugenie Scott has worked to defend the teaching of evolution and climate science in public schools by providing resources to teachers, schools, and citizens and by working on legal aspects of these issues at the local, state, and national levels. Scott, who was appointed as executive director of NCSE in 1987, recently announced her intention to retire from that position.
Scientists and Education/Outreach Professionals Invited to Present at Exploration Station
Authors: Adamec Bethany
Published: July 2013

The AGU Education department is getting ready for another Exploration Station in San Francisco as part of the annual Fall Meeting. Registration for presenters is now open; we invite members to consider becoming a part of this event.
Voyager 1 observes sudden changes in cosmic ray intensity
Authors: Balcerak Ernie
Published: July 2013

The Voyager 1 spacecraft, which was launched in 1977, has reached a new region of space near the edge of the heliosphere, the bubble of charged particles surrounding our solar system. At the edge of the heliosphere is the heliosheath, the region where the solar wind slows down as it hits incoming particles from the interstellar medium. As it traveled through the heliosheath, Voyager 1 recently encountered a dramatic, unprecedented change in the intensity of cosmic rays.
Seismic Hazard and Public Safety
Authors: Marzocchi Warner
Published: July 2013

The recent destructive earthquakes in Wenchuan (China), L'Aquila (Italy), Port‐au‐Prince (Haiti), Christchurch (New Zealand), and Tohoku (Japan) have reignited the discussion over seismic safety. Several scientists [e.g., Stein et al., 2012; Wyss et al., 2012] have questioned the reliability of some seismic hazard maps based on the probabilistic seismic hazard analysis (PSHA)—a widely used probabilistic approach that estimates the likelihood of various levels of ground shaking occurring at a given location in a given future time period—raising an intense discussion on this specific point [Hanks et al., 2012; Frankel, 2013; Stein et al., 2013].
Surface roughness and light‐scattering properties of ice crystals
Authors: Balcerak Ernie
Published: July 2013

Many studies have focused on how the size and shape of ice crystals in clouds affect the clouds' light‐scattering properties, which are important in understanding the effects of clouds on weather and climate; these effects are one of the major sources of uncertainty in climate models. Also important, but less well studied, is how the roughness of ice crystals affects light scattering.
Causality of deep convection from a cloud‐resolving model
Authors: Schultz Colin
Published: July 2013

Understanding deep convection and clouds is among the most important goals of tropical weather and climate dynamics. Deep convection, the vertical transport of buoyant air through the depths of the atmosphere, controls cloud formation and precipitation rates. To help forecast the weather, operational forecasters are beginning to use cloud‐resolving models: atmospheric models with resolutions high enough to adequately represent individual clouds and often a scale broad enough to capture large‐scale patterns in deep convection.
Structure evolution of ultra high molecular weight polyethylene/montmorillonite nanocomposite fibers prepared by melt spinning
Authors: Zhang Qiang , Wang Qingzhao , Chen Yong
Published: July 2013

Nanocomposite fibers of ultra high molecular weight polyethylene (UHMWPE) and organic montmorillonite (OMMT) were successfully prepared by a melt‐spinning process. The evolution of the microstructures of the nanocomposite fibers in the drawing process was preliminarily studied by X‐ray diffraction (XRD), differential scanning calorimetry, and small‐angle X‐ray scatters. With the increase of draw ratio values, the crystallinity of the nanocomposite fibers increased, the grain size decreased, and the folded chain crystals gradually transformed into extended chain crystals. The results suggested the evolution of the nanocomposite fibers was similar with that of the fibers made by gel‐spun drawing process. The addition of OMMT in UHMWPE improved the fluidity of the composites yet without affecting the crystal structure of UHMWPE in the drawing process. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3930–3936, 2013
Synthesis and Radical Scavenging Activities of Resveratrol Analogs
Authors: Csuk René , Albert Sabrina , Siewert Bianka
Published: July 2013

Highly substituted polyhydroxylated (E)‐stilbenes were synthesized by Mizoroki–Heck reactions and tested for their ability to act as radical scavenger. One of the 56 stilbenes included in this study and investigated in DPPH assays gave an SC50 value of 11.0 μM, hence exhibiting an about 9.3 times higher activity than resveratrol. As shown in a photometric SRB assay using mouse NiH 3T3 fibroblasts, this compound is not cytotoxic up to concentrations of <30 μM.
A New V‐Shaped Organic Fluorescent Compound Integrated with Crystallization‐Induced Emission Enhancement and IntramolecularCharge Transfer
Authors: Gu Pei‐Yang , Zhang You‐Hao , Liu Gao‐Yan , Ge Jian‐Feng , Xu Qing‐Feng , Zhang Qichun , Lu Jian‐Mei
Published: July 2013

The emission behavior of a new V‐shaped organic fluorescent compound (p,p′‐bis(2‐aryl‐1,3,4‐oxadiazol‐5‐yl)diphenyl sulfone (OZA-SO), consisting of diethylamino (donor) and sulfone (acceptor) units, has been studied in various polar solvents and with different morphologies. As expected, there is the gradual transition from the locally excited state to the intramolecular charge‐transfer (ICT) state with the increasing solvent polarity. The photoluminescence intensity of OZA-SO initially decreases with a low water fraction (fw), owing to ICT effect, and then increases with a high fw, owing to crystallization‐induced emission enhancement. At the same time, the fluorescence lifetime of OZA-SO increases from 0.062 ns in dimethylformamide (DMF) to 5.80 ns in a solution containing 90 % water, and then to 7.49 ns in a solution containing 60 % water. Furthermore, the solid‐state emission of OZA-SO can be tuned reversibly from green to yellow by fuming/grinding or fuming/heating owing to morphological changes. This color‐switchable feature of OZA-SO may have potential applications in optical‐recording and temperature‐sensing materials.
Structure, function, and tethering of DNA‐binding domains in σ54 transcriptional activators
Authors: Vidangos Natasha , Maris Ann E. , Young Anisa , Hong Eunmi , Pelton Jeffrey G. , Batchelor Joseph D. , Wemmer David E.
Published: July 2013

We compare the structure, activity, and linkage of DNA‐binding domains (DBDs) from σ54 transcriptional activators and discuss how the properties of the DBDs and the linker to the neighboring domain are affected by the overall properties and requirements of the full proteins. These transcriptional activators bind upstream of specific promoters that utilize σ54‐polymerase. Upon receiving a signal the activators assemble into hexamers, which then, through adenosine triphosphate (ATP) hydrolysis, drive a conformational change in polymerase that enables transcription initiation. We present structures of the DBDs of activators nitrogen regulatory protein C 1 (NtrC1) and Nif‐like homolog 2 (Nlh2) from the thermophile Aquifex aeolicus. The structures of these domains and their relationship to other parts of the activators are discussed. These structures are compared with previously determined structures of the DBDs of NtrC4, NtrC, ZraR, and factor for inversion stimulation. The N‐terminal linkers that connect the DBDs to the central domains in NtrC1 and Nlh2 were studied and found to be unstructured. Additionally, a crystal structure of full‐length NtrC1 was solved, but density of the DBDs was extremely weak, further indicating that the linker between ATPase and DBDs functions as a flexible tether. Flexible linking of ATPase and DBDs is likely necessary to allow assembly of the active hexameric ATPase ring. The comparison of this set of activators also shows clearly that strong dimerization of the DBD only occurs when other domains do not dimerize strongly. © 2013 Wiley Periodicals, Inc. Biopolymers 99: 1082–1096, 2013.
Weak operator binding enhances simulated lac repressor‐mediated DNA looping
Authors: Colasanti Andrew V. , Grosner Michael A. , Perez Pamela J. , Clauvelin Nicolas , Lu Xiang‐Jun , Olson Wilma K.
Published: July 2013

The 50th anniversary of Biopolymers coincides closely with the like celebration of the discovery of the Escherichia coli (lac) lactose operon, a classic genetic system long used to illustrate the influence of biomolecular structure on function. The looping of DNA induced by the binding of the Lac repressor protein to sequentially distant operator sites on DNA continues to serve as a paradigm for understanding long‐range genomic communication. Advances in analyses of DNA structures and in incorporation of proteins in computer simulations of DNA looping allow us to address long‐standing questions about the role of protein‐mediated DNA loop formation in transcriptional control. Here we report insights gained from studies of the sequence‐dependent contributions of the natural lac operators to Lac repressor‐mediated DNA looping. Novel superposition of the ensembles of protein‐bound operator structures derived from NMR measurements reveals variations in DNA folding missed in conventional structural alignments. The changes in folding affect the predicted ease with which the repressor induces loop formation and the ways that DNA closes between the protein headpieces. The peeling of the auxiliary operators away from the repressor enhances the formation of loops with the 92‐bp wildtype spacing and hints of a structural reason behind their weak binding. © 2013 Wiley Periodicals, Inc. Biopolymers 99: 1070–1081, 2013.
The changing dielectric properties of CHO cells can be used to determine early apoptotic events in a bioprocess
Authors: Braasch Katrin , Nikolic‐Jaric Marija , Cabel Tim , Salimi Elham , Bridges Greg E. , Thomson Doug J. , Butler Michael
Published: July 2013

To ensure maximum productivity of recombinant proteins it is desirable to prolong cell viability during a mammalian cell bioprocess, and therefore important to carefully monitor cell density and viability. In this study, five different and independent methods of monitoring were applied to Chinese hamster ovary (CHO) cells grown in a batch culture in a controlled bioreactor to determine cell density and/or cell viability. They included: a particle counter, trypan blue exclusion (Cedex), an in situ bulk capacitance probe, an off‐line fluorescent flow cytometer, and a prototype dielectrophoretic (DEP) cytometer. These various techniques gave similar values during the exponential growth phase. However, beyond the exponential growth phase the viability measurements diverged. Fluorescent flow cytometry with a range of fluorescent markers was used to investigate this divergence and to establish the progress of cell apoptosis: the cell density estimates by the intermediate stage apoptosis assay agreed with those obtained by the bulk capacitance probe and the early stage apoptosis assay viability measurements correlated well with the DEP cytometer. The trypan blue assay showed higher estimates of viable cell density and viability compared to the capacitance probe or the DEP cytometer. The DEP cytometer measures the dielectric properties of individual cells and identified at least two populations of cells, each with a distinct polarizability. As verified by comparison with the Nexin assay, one population was associated with viable (non‐apoptotic) cells and the other with apoptotic cells. From the end of the exponential through the stationary and decline stages there was a gradual shift of cell count from the viable into the apoptotic population. However, the two populations maintained their individual dielectric properties throughout this shift. This leads to the conclusion that changes in bulk dielectric properties of cultures might be better modeled as shifts in cells between different dielectric sub‐populations, rather than assuming a homogeneous dielectric population. This shows that bulk dielectric probes are sensitive to the early apoptotic changes in cells. DEP cytometry offers a novel and unique technology for analyzing and characterizing mammalian cells based on their dielectric properties, and suggests a potential application of the device as a low‐cost, label‐free, electronic monitor of physiological changes in cells. Biotechnol. Bioeng. 2013;110: 2902–2914. © 2013 Wiley Periodicals, Inc.
Recasting Stigma as a Dialogical Concept: A Case Study of Rural‐to‐Urban Migrants in China
Authors: Guan Jian , Liu Li
Published: July 2013

The present study explores stigma against rural‐to‐urban migrants in China, drawing on a dialogical approach. It investigates the processes of stigmatization from two sides: that of the stigmatizer and that of the stigmatized. Open‐ended individual interviews were conducted with 138 participants (60 urban residents and 78 rural‐to‐urban migrants) in Tianjin, China. Findings from this study indicate that migrants were stigmatized by urban residents as having an unattractive physical appearance, potential perils of disease or crime, and discredited places of origin. Such stigma was embedded in China's unique hukou system and generated from a social categorization of superior and inferior groups. Migrants reported a number of coping strategies to counter such stigma: blaming fate, stigma reversal and upward mobility. However, migrants did not view themselves contemptuously and expressed positive feelings about their lives as migrants. They regarded internal migration as a way of pursuing happiness. Overall, urban residents stigmatized migrants legitimated by the hukou system, while migrants were surprisingly resilient against stigma, and did not internalize it, due to their economics‐driven internal migration. This study underscores that stigma in a given society is dialogically interdependent with its socio‐cultural context and that the perspectives of both the stigmatizer and the stigmatized need to be taken into consideration. Copyright © 2013 John Wiley & Sons, Ltd.
Mechanistic Study of the Oxidative Steam Reforming of EtOH on Rh(111): The Importance of the Oxygen Effect
Authors: Syu Cih‐Ying , Wang Jeng‐Han
Published: July 2013

This study extensively investigates the catalytic mechanism and oxygen effect in the oxidative steam reforming (OSR) of EtOH on Rh(111) by using plane‐wave density functional theory (DFT) and kinetic calculations. The mechanistic results show that both surface acetaldehyde (CH3CHO*) and oxametallacycle (CH2CH2O*) species from CαH and CβH bond scissions of surface ethoxy (CH3CH2O*) groups, respectively, are key intermediates. Both of these species can quickly decomposed into surface carbon (C*), methylidyne (CH*), and carbon monoxide (CO*) species, owing to energetic preferences. However, the removal of the adspecies in the formation of major products CO(g) and CO2(g) through high‐barrier oxidation steps are considered the rate‐determining steps in the overall catalytic process. In the study of the oxygen effect, surface oxygen (O*) species might slightly elevate the barriers for EtOH decomposition, but can lower the barriers for the rate‐limiting oxidation steps. The kinetic calculations, which well‐predict the experimental observations, indicate that the rates of those oxidation steps can be further increased at high oxygen pressures. These results conclude that the oxygen effect plays a crucial role in the OSR of EtOH on Rh‐based catalysts and further implies that the catalytic performance can be improved by using promoters, which have better oxidative capability, and by increasing the oxygen content, which can assist the oxidation process.
Cobalt‐Catalyzed CH Bond Functionalizations with Aryl and Alkyl Chlorides
Authors: Punji Benudhar , Song Weifeng , Shevchenko Grigory A. , Ackermann Lutz
Published: July 2013

Inexpensive cobalt catalysts derived from N‐heterocylic carbenes (NHC) allowed efficient catalytic CH bond arylations on heteroaryl‐substituted arenes with widely available aryl chlorides, which set the stage for the preparation of sterically hindered tri‐ortho‐substituted biaryls. Likewise, challenging direct alkylations with β‐hydrogen‐containing primary and even secondary alkyl chlorides proceeded on pyridyl‐ and pyrimidyl‐substituted arenes and heteroarenes. The cobalt‐catalyzed CH bond functionalizations occurred efficiently at ambient reaction temperature with excellent levels of site‐selectivities and ample scope. Mechanistic studies highlighted that electron‐deficient aryl chlorides reacted preferentially, while the arenes kinetic CH bond acidity was found to largely govern their reactivity.
Encapsulation of Metalloporphyrins in a Self‐Assembled Cubic M8L6 Cage: A New Molecular Flask for Cobalt–Porphyrin‐Catalysed Radical‐Type Reactions
Authors: Otte Matthias , Kuijpers Petrus F. , Troeppner Oliver , Ivanović‐Burmazović Ivana , Reek Joost N. H. , de Bruin Bas
Published: July 2013

The synthesis of a new, cubic M8L6 cage is described. This new assembly was characterised by using NMR spectroscopy, DOSY, TGA, MS, and molecular modelling techniques. Interestingly, the enlarged cavity size of this new supramolecular assembly allows the selective encapsulation of tetra(4‐pyridyl)metalloporphyrins (MII(TPyP), M=Zn, Co). The obtained encapsulated cobalt–porphyrin embedded in the cubic zinc–porphyrin assembly is the first example of a catalytically active encapsulated transition‐metal complex in a cubic M8L6 cage. The substrate accessibility of this system was demonstrated through radical‐trapping experiments, and its catalytic activity was demonstrated in two different radical‐type transformations. The reactivity of the encapsulated CoII(TPyP) complex is significantly increased compared to free CoII(TPyP) and other cobalt–porphyrin complexes. The reactions catalysed by this system are the first examples of cobalt–porphyrin‐catalysed radical‐type transformations involving diazo compounds which occur inside a supramolecular cage.