bluuebunny/crossref_metadata_2025 huggingface dataset:
Scientific teams analyze earthquake hazards of the Cascadia Subduction Zone
Authors: Flueh Ernst , Fisher Michael , Scholl David , Parsons Tom , Brink Uri Ten , Klaeschen Dirk , Kukowski Nina , Trehu Anne , Childs Jonathan , Bialas Joerg , Vidal Neus
Published: October 2006

Scientists from GEOMAR, the U.S. Geological Survey (USGS), and Oregon State University recently collected seismic reflection and wide‐angle seismic data for the continental margin off the Oregon and Washington coasts—a subduction zone that poses a significant earthquake hazard to populated areas of the Pacific Northwest. Geologic findings indicate that great earthquakes (magnitude 8 to 9) have occurred within the Cascadia subduction zone and that an earthquake of this magnitude could some day devastate urban areas of the Pacific Northwest. One such quake may have rocked this region as recently as 300 years ago, and the debate concerning the imminence of the next one continues [Heaton and Kanamori, 1984; Atwater, 1992; Hyndman and Wang, 1993; Wang et al., 1995; Satake et al., 1996]. Potential earthquake source regions along the interplate decollement are unexplored. In fact, the geometry of the downgoing Juan de Fuca plate beneath Oregon and Washington has been poorly understood because of the paucity of shallow (<30 km) earthquakes.
The Reconnection Myth
Authors: Heikkila Walter J.
Published: October 2006

The concept of magnetic reconnection for the interaction of the solar wind plasma with the Earth's magnetosphere is illustrated by Dungey's [1961] classic drawing (Figure 1a). According to this concept, the interplanetary magnetic field (IMF) lines, frozen in to the antisunward solar wind plasma flow, divide, or disconnect, at an X‐line at the magnetopause, with one end going over the north pole and the other end over the south pole. The polar cap field lines are called “open,” with only one end connected to the Earth; the total amount of open flux over the two polar caps must be the same to conform to Maxwell's equations.
Second tour of duty
Authors: Carlowicz Michael
Published: October 2006

The Jet Propulsion Laboratory (JPL) and NASA have tentatively agreed to extend the Galileo mission to Jupiter and its satellites. The Galileo Europa Mission (GEM), set to begin in December 1997 and end in December 1999, would bring the spacecraft back into close proximity to the moons Europa and Io.
1998 U.S. Federal Budget: House budget authorization includes similar funding, different priorities
Authors: Anonymous
Published: October 2006

In mid‐April, the Science Committee of the U.S. House of Representatives reviewed a set of bills to authorize research funding for the Environmental Protection Agency (EPA), the National Science Foundation (NSF), the National Aeronautics and Space Administration (NASA), and the National Oceanic and Atmospheric Administration (NOAA). In a turnabout from the 104th Congress, the committee authorized more spending than was requested by the Clinton Administration for fiscal year 1998 (Eos, February 18). But the committee also expressed its own ideas—some of them conflicting with the President's—about what U.S. science priorities ought to be.
Magnetic map will define Antarctica's structure
Authors: Johnson A. C. , von Frese R. R. B. ,   ADMAP Working Group
Published: October 2006

A new, multinational, Antarctic Digital Magnetic Anomaly Project (ADMAP) has been launched to compile near‐surface and satellite magnetic anomaly data into a digital map and database for the Antarctic continent and surrounding oceans. The unified data set will be a powerful tool for determining the structure, geologic processes, and tectonic evolution of the continent.
Delory receives Scarf Award
Authors: Anonymous
Published: October 2006

Gregory T. Delory will be presented with the 1997 F.L. Scarf Award during the AGU 1997 Spring Meeting in Baltimore, Maryland, held from May 27 to May 30. The award is given annually to a recent Ph.D. recipient for outstanding dissertation research that contributes directly to solar‐planetary science.
Autonomous underwater vehicle maps seafloor
Authors: Tivey Maurice A. , Bradley Albert , Yoerger Dana , Catanach Rodney , Duester Alan , Liberatore Steve , Singh Hanu
Published: October 2006

Autonomous underwater vehicles (AUVs)—which operate without a tether or human supervision—represent an emerging technology that can be used to solve many scientific problems in the deep ocean, the last unexplored frontier on Earth. AUVs are well suited to “lawn‐mower” style geophysical surveys for mapping bathymetry, magnetic field, or water column properties. They are fast and efficient synoptic mappers and are inexpensive to operate.

Manned submersibles and remotely operated vehicles (ROVs) allow intensive study of an area, but can remain at a site for only a few hours, days, or weeks. AUVs can remain in an area gathering data in between submersible and ROV visits to provide information on temporal variations and can respond rapidly to events such as volcanic eruptions when large oceanographic vessels and equipment cannot be mobilized quickly.
Integrated satellite interferometry in Southern California
Authors: Bock Yehuda , Williams Simon
Published: October 2006

Geodetic studies of crustal deformation and earthquakes in California, which began with the analysis of repeated triangulation measurements after the 1906 San Francisco earthquake, have been revolutionized by new satellite interferometric techniques in space geodesy and remote sensing. Today, space geodetic monitoring of crustal deformation at regional scales relies on a combination of continuous Global Positioning System regional arrays (CGPS), such as the Southern California Integrated GPS Network (SCIGN), and less frequent field GPS surveys. A global continuous GPS array, the International GPS Service for Geodynamics (IGS), provides precise satellite ephemerides and a well‐defined terrestrial reference frame. Data from CGPS arrays can also be used to map tropospheric water vapor and ionospheric disturbances.
Mountain building and active deformation studied in New Zealand
Authors: Stern T. A. , Wannamaker P. E. , Eberhart‐Phillips D. , Okaya D. , Davey F. J. ,   South Island Project Working Group
Published: October 2006

Strong, eastward dipping (∼40°) reflectors found 23 km below the central South Island were recorded by a joint U.S.‐New Zealand geophysical project during austral summer 1995–1996. When projected to the surface, the reflectors define a plane that coincides with the surface trace of the Alpine Fault (Figure 1).

Data processing is still at an early stage, but preliminary results, reported at a workshop held at Victoria University of Wellington February 17–19, 1997, give an overall picture of asymmetric crustal thickening and active processes in the mid to lower crust. A jump in crustal thickness of about 20 km is inferred across the Alpine Fault, and the locus of thickening does not occur beneath the highest mountains, but is imaged at least 20 km farther to the east. Low seismic velocities and high electrical conductivity roughly coincide with the strong eastward‐dipping reflections in the mid to lower crust. Excess fluids and high pore pressure probably explain both the low seismic velocities and high electrical conductivity.
Zero‐phase FIR filters: Blessing or curse?
Authors: Scherbaum Frank
Published: October 2006

These are exciting times for observational seismology. State‐of‐the‐art broadband seismometers now easily cover a frequency band of more than one hundred seconds to several tens of Hertz in a single sensor. Commonly available data loggers provide a dynamic range exceeding 120 dB. Ground motion amplitudes differing by more than 6 orders of magnitude can be simultaneously recorded without distortion.
Mars has crustal, complex magnetic field
Authors: Showstack Randy
Published: October 2006

Scientists working on the Mars Global Surveyor project announced last week that new satellite evidence indicates that the magnetic field around Mars is most likely of crustal rather than dynamo origin. They also say that the field is much stronger than previously anticipated and that it could greatly vary in strength in different locations on the planet.

“Based on evidence collected over several orbits, we now have strong evidence that the field is of crustal origin,” says Mario Acuña, an astrophysicist at NASA's Goddard Space Flight Center who is the principal investigator for the magnetometer and electron reflectometer instruments on the satellite.
Einstein and geophysics: Valuable contributions warrant a second look
Authors: Schröder Wilfried , Treder Hans‐Jürgen
Published: October 2006

All scientists know that Albert Einstein's work transformed the principles of physics in atomistic, quantum mechanics, and relativity theory. Many of Einstein's fundamental investigations proved to be relevant to geophysical research as well, though his contributions are often overlooked. Einstein's General Relativity Theory (GRT) initiated a new chapter not only in astronomy, but also in geophysics. Models of the universe based on Einstein's ideas nowadays underpin the main fields of cosmic geophysics, and his basic work on relativistic astrophysics and related fields of science captured the interest of geophysicists such as Emil Wiechert and Hans Ertel.
Comment on “Climate control requires a dam at the Strait of Gibraltar”
Authors: Marotzke Jochem , Adcroft Alistair
Published: October 2006

While we appreciate the editor's desire to publish contributions of general scientific interest, societal relevance, and controversial nature, Eos should not sacrifice scientific rigor to achieve this. Publication of "Climate Control Requires a Dam at the Strait of Gibraltar" by R. G. Johnson (Eos, July 8,1997) was irresponsible. The connection between Mediterranean salinity and ice age initiation is only postulated but not substantiated through quantitative reasoning supported by data.

Climate is complex because many competing feedbacks act simultaneously. Even if every single one of the hypothesized mechanisms were correct, there would always be competing effects, so quantitative analysis is needed to determine the net response. For example, it is hypothesized that a warming of the Labrador Sea would lead to additional land ice formation, but one could argue equally well that the extra ice would simply melt because the surroundings were warmer. Some of the postulated mechanisms are blatantly inconsistent with what is known about fluid mechanics (e.g., the existence of the “fluidic switch,” through which, apparently, a tiny current can deflect a large one) or about climate dynamics (if global warming could indeed lead to an ice age, i.e., global cooling, current climate would be unstable).
Physical Properties of Rocks: Fundamentals and Principles of Petrophysics
Authors: Wilkens Roy H.
Published: October 2006

When you get right down to it, most of what geoscientists believe they know about the structure and workings of the solid earth is based very little on direct observation and to a great extent on interpreting geophysical measurements. The mortar that has been used to build that understanding—the ties between what we can get our hands on and what we can only measure—is petrophysics.

Laboratory measurements of shear and compressional wave velocity, density, porosity, electrical resistivity, thermal conductivity, and a host of other properties have been carried out many thousands of times under differing conditions in laboratories throughout the world. While physical models and empirical relationships interrelating these properties have been built over time, curiously few attempts have been made to summarize this wide array of work in a single volume. Books focusing on laboratory techniques, particular properties (most notably acoustics), or physical theories have been written; however, when a student enters my office looking for help in translating seismic velocities in a particular setting into density, porosity, or lithology, I still find myself handing him or her a list of papers and book chapters rather than a single source. No more.
The Sun as a Star
Authors: Bell Jim
Published: October 2006

This is an exciting time for studies of the Sun. Ulysses, Solar and Heliospheric Observatory (SOHO), and other missions daily return data that explore the radiative, magnetic, and seismologic nature of our nearest stellar neighbor. New and existing models of the origin and evolution of the Sun are becoming more complex and mature, as our database of knowledge on other stars—Sun‐like and not so Sun‐like—continues to expand. Perhaps most relevant to geophysicists is our increasing awareness of the role that the Sun has played, and continues to play, in the origin and evolution of the solar leftovers: those planets, satellites, and billions of asteroids and comets that we call the solar system.
Survey Provides Seismic Insights Into an Old Suture Zone
Authors: Krawczyk Charlotte M.
Published: October 2006

Initial results of a new marine survey in the Baltic Sea may shed light on the hotly debated geodynamic evolution of the complex North German Basin. Data reveal continuation of fault structures mapped onshore,s edimentary inversion structures, deep crustal and upper mantle structures, and the Moho depth.

Fault‐bounded half grabens of the Triassic Age were imaged, for example, and these were almost invariably inverted during the Cretaceous [Er/strom et a/., 1997]. This differs completely from structures found so far in other parts of the basin, which shows little extensional faulting and inversion at its southern rim profile. Data also suggest collision tectonics with flake geometry in the basin. This may help to solve the evolutionary puzzle of whether Baltica overrode Avalonia during collision or whether the structures represent older deformation.
Worldwide database for magnetostratigraphy available
Authors: McElhinny Michael W. , Opdyke Neil D. , Pisarevsky Sergei A.
Published: October 2006

The International Association of Geomagnetism and Aeronomy (IAGA) has sponsored the development of databases in paleomagnetism and rock magnetism. The databases operate under Microsoft Access V2.0 (for Windows 3.1) or Access 97 (for Windows 95) [McElhinny and Lock, 1996]. Following the publication of the first major book in English on magnetostratigraphy by Opdyke and Channell [1996], we have set up a worldwide database for magnetostratigraphy. The new database is based on the summaries of western data given by Opdyke and Channell [19967rsqb; but also includes all data available from the former Soviet Union.
Drilling reveals transition from continental breakup to early magmatic crust
Authors:   ODP Leg 173 Shipboard Scientific Party
Published: October 2006

For the first time in an ocean‐continent transition zone (OCT), drilling has sampled rocks above and below what appears to be a synrift tectonic crust‐mantle contact. Research in the West Iberia OCT is assembling important data on the histories and ages of the basement rocks there. The principal result has been to show that evolution of the margin was dominated by extensional tectonics with only slight evidence of possible synrift melting.

A significant preliminary finding of the recently completed Leg 173 of the Ocean Drilling Program (ODP) is that many, if not all, fault blocks underlain by a low‐angle reflector on multichannel seismic profiles under the 5000‐m deep Iberia Abyssal Plain consist of continental crust and are quite thin. The drilling has also shown that lower crust and peridotite became exposed in the OCT between the blocks of continental crust and the first products of oceanic accretion over a zone that appears to be tens of kilometers wide. This supports the hypotheses that predict a broad zone of upper mantle basement beneath the sediments in the development of the West Iberia zone. Preliminary observations of textural and compositional variations of the peridotite from east to west suggest that further studies will document the evolution of the mantle from continental breakup to oceanic accretion.
Streams in Catskill Mountains still susceptible to acid rain
Authors: Burns Douglas A. , Lawrence Gregory B. , Murdoch Peter S.
Published: October 2006

Precipitation in North America has become less acidic over the past 2 decades because of reduced power plant emissions and compliance with the Clean Air Act Amendments [Sirois, 19937rsqb;. The 1990 Clean Air Act Amendments were developed to reduce the acidity of sensitive surface waters, which are primarily in upland forested environments, where acidified waters and associated high aluminum concentrations are toxic to many species of aquatic flora and fauna [Schindler et al., 1989]. Our studies show that in spite of less acidic precipitation, the buffering capacity of streams in upland forests of the Catskill Mountains in southeastern New York has not increased in recent years. These data suggest that long‐term leaching by acid rain has lowered exchangeable calcium ion concentrations in the soil in upland areas, where the underlying, slow‐weathering bedrock provides an inadequate supply of cations to neutralize acidity.
Indian nuclear tests prompt worldwide concern
Authors: Showstack Randy
Published: October 2006

India's attempt in mid‐May to blast its way into the nuclear age with the detonation of several underground nuclear tests at a desert site near the Pakistan border left many people around the world shocked and angry about the dangerous escalation in southern Asia's arms race and the threat to the Comprehensive Nuclear Test Ban Treaty.

U.S. President Bill Clinton moved quickly to cut off direct aid and block billions of dollars worth of development bank assistance. Many other nations, including Pakistan, which has fought several wars with India, condemned the explosions. However, Indians appear to widely support the tests.
Spaceborne sensors observe El Niño's effects on ocean and atmosphere in North Pacific
Authors: Liu W. Timothy , Tang Wenqing , Hu Hua
Published: October 2006

Three regions of simultaneous anomalous warming observed in the North Pacific Ocean at the end of May 1997 (Figure 1) are related to wind anomalies through different mechanisms, NASA's high‐resolution Scatterometer (NSCAT) [Liu et al., 1998] reveals. The anomalous warming along the equator is part of the developing El Niño and is related to the westerly wind anomalies in the central equatorial Pacific and the relaxation of the trade winds. The equatorial westerly wind anomalies are related to the anomalous cyclonic wind pattern in the northeast Pacific.
First Congress of the United States tackled geophysics in 1789
Authors: Silverman Sam
Published: October 2006

When the first Congress of the United States under the new Constitution convened in the spring of 1789, one of the first orders of business involved a geophysical project. This involved, first, a petition from John Churchman for protection of an invention for determination of longitude using magnetic variation, and second, a request for congressional support for a voyage to Baffin's Bay to determine the cause of the magnetic variation. The discussions and arguments are an instructive introduction to those that arise when Congress considers scientific projects.

The new government came into being after ratification by the requisite nine states. The new Congress met for the first time on March 4, 1789, in New York, but almost immediately adjourned in the absence of a quorum.
Program aims to reduce impact of tsunamis on Pacific states
Authors: Bernard Eddie N.
Published: October 2006

A state/federal partnership is underway to lessen the impact of tsunamis in U.S. communities along the Pacific Ocean. Now in its second year, the National Tsunami Hazard Mitigation Program is continuing to prepare tsunami inundation maps, construct deepocean tsunami detectors, upgrade seismic networks, and develop mitigation plans for each state along the Pacific coast. Goals include providing early warning of tsunamis and educating residents about evacuation.

Coastal communities in Alaska, northern California, southeastern Hawaii, Oregon, and Washington are particularly threatened by tsunamis generated by local earthquakes. For example, there is mounting geological and seismological evidence that a number of large, local earthquakes in the past 2000 years generated tsunamis resulting in sudden and extensive flooding along the coastlines of Washington, Oregon, and California [Clague, 1997]. The earthquake zones shown in Figure 1 subject all five Pacific states to local tsunami threat. These zones and other seismically active areas of the Pacific rim also expose these states to distant tsunami hazard.
Arrhenius and the Intergovernmental Panel on Climate Change
Authors: Lapenis Andrei G.
Published: October 2006

Svante August Arrhenius was the first to calculate global climate sensitivity to changes in atmospheric CO2 concentration. He was also the first to calculate the anthropogenic rate of CO2 buildup in the modern atmosphere. There is apparently an inconsistency, however, between the references to these estimates [e.g., Uppenbrink, 1996] and the real numbers Arrhenius derived in his later works.

The citations of Arrhenius' calculations are usually based on the work published in 1896 [Arrhenius, 1896]. In this paper Arrhenius reported that CO2 doubling should increase the Earth's mean temperature by 5–6°C. In the same ear, he estimated that it would take about 3000 y ears for mankind to double the atmospheric concentration through the burning of fossil fuels [Arrhenius, 1896]. However, the 1896 paper was not his last publication on the problem of global warming.
Educational Outreach Strategy involves K‐12 students in earthquake hazard research
Authors: Sauber J. , Stockman S. , Clark T.
Published: October 2006

NASA has been making precise geodetic measurements to assess earthquake hazard associated with the subduction zone process in Alaska since 1984. In 1995, a new strategy for making geodetic measurements was implemented that included local residents in the measurement program, and in 1997, the program was expanded to include teachers and students at five high schools. For the inhabitants of Alaska, understanding the hazards and underlying physical processes associated with earthquakes has immediate personal relevance. Large earthquakes occur yearly, great earthquakes have occurred during the lifetime of many residents, and the weekly testing of the tsunami warning system in coastal towns is a reminder of the devastation caused by earlier tsunamis generated near Alaska and a cautionary note about future inundation.
Arrhenius and current climate concerns: Continuity or a 100‐year gap?
Authors: Fleming James Rodger
Published: October 2006

In a paper presented to the Stockholm Physical Society in 1895 and published the following year, Svante Arrhenius demonstrated that variations of atmospheric CO2 concentration could have a very great effect on the overall heat budget and surface temperature of the planet. It would be a mistake, however, to consider this work as a direct forerunner of current climate concerns [Uppenbrink, 1996].

Arrhenius, who has recently gained renewed attention as the “father” of the theory of the greenhouse effect, held assumptions and produced results that are not continuous with present‐day climate research. For example, he suggested that increasing the carbon dioxide content of the atmosphere by burning fossil fuels might be beneficial, making the Earth's climates warmer and “more equable,” stimulating plant growth, and providing more food for a larger population [Arrhenius, 1908]. Arrhenius's view of the potentially beneficial effects of carbon dioxide emissions differs radically from current concerns over the harmful effects of a global warming caused by industrial activity and deforestation [Fleming, 1998].
Search for a mantle plume under central Europe
Authors: Ritter J. R. R. , Christensen U. R. R. , Achauer U. , Bahr K. , Weber M. H.
Published: October 2006

A multidisciplinary team of scientists has begun searching for a mantle plume under the Eifel region in central Europe and has already detected a plume‐like structure. The researchers, from a number of European institutions, hope to establish the existence of a plume, thereby explaining better than in the past the known thermal mantle anomaly beneath the region.

Known as the Eifel Plume Project, the research involves a seismic network spanning nearly 500 km × 500 km. Fieldwork began in 1997 and continued until summer 1998.
A misuse of public funds: U.N. support for geomagnetic forecasting of earthquakes and meteorological disasters
Authors: Campbell Wallace H.
Published: October 2006

The legitimate scientific community needs to be alerted to the expenditure of considerable public funds forpseudoscientific projects that build false hopes of protection from geophysical hazards. One example of such a project is a recently published, 147‐ page United Nations (U.N.) document titled “Manual on the Forecasting of Natural Disasters: Geomagnetic Methods.” Although the document has been distributed internationally, it seems not to have been subjected to pre‐publication, international peer review.

The manual was prepared for a U.N. international workshop recently held in Beijing, China, from February 12 to 18,1998. The meeting was sponsored by the Chinese Academy of Sciences, the State Seismological Bureau of China, the U.N. Global Programme for the Integration of Public Administration and Science of Disasters in the Department for Economic and Social Affairs (DESA), and the U.N. Development Programme (UNDP) in Beijing.
Disturbed space environment may have been related to pager satellite failure
Authors: Baker D. N. , Allen J. H. , Kanekal S. G. , Reeves G. D.
Published: October 2006

A very intense flux of electrons, evident in the magnetosphere earlier this year, may have caused a satellite failure (or at least exacerbated the situation) leading to the loss of pager service to 45 million customers, research has shown. The electrons, known as highly relativistic electrons (HREs), were especially numerous in the weeks preceding the failure. Researchers say HREs have triggered spacecraft anomalies in the past through a process of deep dielectric charging when fluxes are elevated. They therefore believe this energetic electron environment could have been behind the failure in the attitude control system of the Galaxy 4 spacecraft at 2200 UT on May 19,1998. A backup system also failed, either at the same time or earlier, so operators were unable to maintain a stable Earth link [Silverstein, 1998].
GOES imagery fills gaps in Montserrat volcanic cloud observations
Authors: Davies Mark A. , Rose William I.
Published: October 2006

GOES satellite imagery offers great potential to lessen the risk of volcanic ash clouds to aviation, and the situation at Montserrat in the Caribbean is providing the proof. Many transatlantic, commercial, and private aircraft use airspace around Montserrat, where the Soufriere Hills Volcano has been erupting since 1995.

Worldwide over the last 15 years, more than 80 airplanes have reported encountering volcanic ash along flight paths. Encounters cannot be avoided because onboard radar cannot detect fine‐grained ash particles—those with a radius of 15 microns or less. In recent years volcanic cloud encounters are estimated to have caused hundreds of millions of dollars worth of damage and in a few cases have caused in‐flight engine failure [Casadevall et al., 1996].
New program maps geoscience data sets interactively
Authors: Becker Thorsten W. , Braun Alexander
Published: October 2006

During the last decade many new and improved global geoscience data sets have been evaluated by researchers around the world. While new techniques such as satellite altimetry were developed to compute the geoid and marine gravity field to high resolution, existing data sets such as earthquake catalogs and hotspot location lists were enhanced.

These data sets contain invaluable information for every Earth scientist whether the focus is global or regional. With the advent of high‐speed Internet connections, global access to these immense resources is now easy, but actual processing still poses some obstacles.
Coordinated effort in progress to decipher Cenozoic ice sheet evolution
Authors: Barker Peter , Cooper Alan K.
Published: October 2006

The Antarctic cryosphere has had a major effect on Cenozoic global climates, sea levels, oceanography, and Southern Hemisphere biota. Yet the climatic history of Antarctica and its contribution to global climates remain mostly unknown. Our understanding of Antarctic ice sheet history comes largely from sampling the ocean basins around Antarctica because few Cenozoic rocks are exposed onshore. Extensive seismic data and seafloor cores have been collected from the Antarctic continental margin during the past 4 decades, as well as limited drill cores through, for example, the Deep Sea Drilling Program (DSDP) and the Ocean Drilling Program (ODP). These data are the foundation for a new coordinated effort to core and drill the margin to derive the Cenozoic history of Antarctic ice sheet fluctuation.
Looking back on a half century of repeat magnetic measurements in France
Authors: Alexandrescu Mioara Mandea , Gilder Stuart , Courtillot Vincent , Le Mouël Jean Louis , Gilbert Daniel
Published: October 2006

Birds do it. Bees do it. And with the discovery of lodestone over 2200 years ago, humans too could incorporate the Earth's magnetic field into their daily lives. Some of the oldest applications for tracking the magnetic field were in land and sea navigation. Magnetic field measurements quickly became an important economic factor in world trade, with documented use dating from the 11th century in China.

The measurements are important in other applications as well. For example, rapid field variations are generated by solar activity and its interaction with the terrestrial environment. Large magnetic storms can disrupt satellite operation, communication systems, power transmission networks, and so forth [Campbell, 1997].Geomagnetism also provides a unique opportunity to explore the Earth's outer core, which is mostly liquid (molten) iron, where the field is generated. Field measurements can also yield valuable insights into the location of mineral deposits and aid in applications in the petroleum industry.
Collaborating “ocean ecologists” assess achievements, prepare for challenges
Authors: Hay Mark , Jumars Peter
Published: October 2006

Remarkable advances in our understanding of the biology and ecology of the world's oceans are leading to a newer, more integrative approach to investigations of those oceans. The approach, which we have called “ocean ecology” is blurring previous distinctions between marine ecology and biological oceanography. Researchers in those fields now collaborate and trade methods and scientific perspectives and, as a result, find themselves part of the intellectual underpinnings and histories of subdisciplines other than their own.

Collaboration comes none too soon. One of the greatest challenges facing ocean ecologists in the present and coming decades is understanding and resolving anthropogenic versus natural variability and change. The need is urgent to focus investigations on coastal ocean degradation and its acceleration and to deal effectively with environmental change wrought by humans.
Airborne laser study quantifies El Ni˜o‐induced Coastal Change
Authors: Sallenger Asbury H. , Krabill William , Brock John , Swift Robert , Jansen Mark , Manizade Serdar , Richmond Bruce , Hampton Monty , Eslinger David
Published: October 2006

Winter storms during the 1997–1998 El Niño caused extensive changes to the beaches and cliffs of the west coast of the United States, a NASA‐NOAA‐USGS investigation using a scanning airborne laser has found. For example, near Pacifica in central California, the cliff eroded locally as much as 10–13 m landward during the El Niño winter, at least 40 times the long term average erosion rate. However, only several hundred meters away the cliff was stable. This variability in cliff response may be related to differences in local beach changes where an accreting beach protected part of the cliff and an eroding beach exposed another part to attack by waves.
Report outlines continued importance of ground‐based solar studies
Authors: Showstack Randy
Published: October 2006

Observations of the Sun from space have provided some stunning imagery and scientific data that could not be gained from the Earth. But a new report emphasizes that ground‐based solar observations continue to be vital, and that there is an urgent need to develop a coherent strategy for ground‐based research in the United States that addresses aging facilities and limited capabilities to pursue important scientific problems.

The report by the Space Studies Board of the National Research Council,“Ground‐Based Solar Research: An Assessment and Strategy for the Future,” says that ground‐based programs are required for research involving spatial and temporal resolution and long‐term synoptic coverage. In addition, the report notes that ground‐based facilities provide the solar‐physics community with easy accessibility, are a means for providing hands‐on education for the next generation of solar researchers, are relatively easy to repair or replace, and typically cost far less than space‐based instruments.
NASA nabs a Webby
Authors: Showstack Randy
Published: October 2006

While Shakespeare and Steven Spielberg garnered Oscars at the Academy Awards last week, NASA came home with a Webby People's Voice Award for “best science site.” The Webby, presented by the International Academy of the Digital Arts and Sciences, recognized the Science@NASA site (http://science.nasa.gov), which received support from people who voted online.

“This is really an exceptional honor for all of us here at the Space Sciences Laboratory, at the Marshall Space Flight Center, and at NASA,” said John Horack, director of NASA/Marshall's science communications process in Huntsville, Ala.
Preliminary results are in from mid‐ocean ridge three‐dimensional seismic reflection survey
Authors: Singh S. C. , Sinha M. C. , Harding A. J. , Kent G. M. , Barton P. J. , Orcutt J. A. , White R. S. , Hobbs R. W.
Published: October 2006

The first three‐dimensional (3‐D) seismic reflection survey of a mid‐ocean ridge was shot in 1997 and, while it is still too early for firm interpretations of the data, it can be confirmed that significant crustal melt bodies have been located and one widely accepted model does not seem to apply to the presence of a robust magma supply there.

The survey the Anatomy of a Ridge‐Axis Discontinuity (ARAD) experiment, was centered over an overlapping spreading center (OSC) system that offsets the ridge axis at 9°03′ north latitude on the East Pacific Rise (EPR) (Figure 1). It was conducted aboard the R/V Maurice Ewing during September and October and included a coincident 3‐D crustal seismic tomography experiment.
Why do auroras look the way they do?
Authors: Stenbaek‐Nielsen H. C. , Hallinan T. J. , Peticolas L.
Published: October 2006

One of the Earths great natural spectacles is the aurora, which may be seen visually on clear nights from locations at high northern and southern latitudes. The auroras occur in the upper atmosphere (∼100 km altitude),and they are caused by energetic particles, primarily electrons, guided into the atmosphere by the Earth's magnetic field. Hence, structure observable in the aurora is often aligned with the geomagnetic field. Figure 1 shows an active aurora, as it is often seen in Alaska. The aurora can be very active, and perhaps most spectacular is the expansive phase of the auroral substorm, in which bright and very dynamic auroras spread over many degrees of latitude on the nightside of the Earth releasing energy at rates comparable to the U.S. electric energy consumption.
New strategy needed in earthquake, volcano monitoring
Authors: Thatcher Wayne
Published: October 2006

Recent advances in space geodesy provide unprecedented opportunities for measuring and understanding processes related to earthquake occurrence and volcanic eruptions in the United States and elsewhere. The Global Positioning System (GPS) uses Earth‐orbiting satellites to obtain relative movements of ground points accurate to a few millimeters, either through periodically repeated surveys or by continuous measurements at permanent sites [Segall and Davis, 1997]. Satellite interferometric synthetic aperture radar (InSAR) uses repeat‐pass radar backscatter images of Earth's surface to obtain complete spatial mappings of surface deformation over 100 km × 100 km scenes to centimeter precision [Massonnet and Feigl, 1998].

During the past 5 years GPS and InSAR increasingly have been applied to local studies of active fault zones and volcanic systems, imaging the sources of deformation buried in Earth's crust and quantifying the hazards they pose to society. The potential now exists to deploy these tools to map and monitor all of the actively deforming western United States, and a new scientific initiative with these goals is under active discussion [Silver et al, 1998].
Chances and changes: The detection of long‐term trends in the ionosphere
Authors: Rishbeth Henry
Published: October 2006

Global change is a hot topic. Everyone has heard the debate on “global warming”: is it real, can it be reliably measured, what are its consequences? Long‐term change with practical consequences may exist in the solar‐terrestrial physics (STP) environment as well. Writing from a personal viewpoint, I argue that: ionosonde data are relevant to the debate; data analysis must be accurate and painstaking; subsequent analysis and interpretation must be thoughtful; the ionospheric record is not yet long enough to establish trends beyond doubt, largely because of the 11‐year solar cycle; and a “core” program of ionospheric monitoring should continue indefinitely
USGS Study reveals a decline in long‐record streamgages
Authors: Lanfear Kenneth J. , Hirsch Robert M.
Published: October 2006

Every year more than 100 USGS streamgaging stations with record lengths (more than 30 years) are being discontinued due to lack of funding. This trend, described in a recent USGS report to Congress, is troublesome in light of the many issues hydrologists and engineers must address in the coming years.

Although there is considerable year‐to‐year variability the underlying dynamic characteristics of the population of USGS streamgages have changed from 30 years ago. During the peak 1959–1968 growth period, the number of active 30‐year record stations increased by about 90 stations per year. A combination of increased station mortality and increased reactivation rates since 1968 means that stations are coming into and out of active collection phases much more quickly than before 1968.
Rotational spectroscopy and molecular structure of the 1,1-difluoroethylene-acetylene complex
Authors: Leung Helen O. , Marshall Mark D.
Published: October 2006

Fourier transform microwave, rotational spectra in the 6–21GHz region are obtained for the complex formed between 1,1-difluoroethylene and acetylene, including the normal isotopomer and each singly substituted C13 species along with complexes derived from commercially available isotopic varieties of acetylene (HCCD, DCCD, and HC13C13H). Although two possible planar structures are consistent with the rotational constants derived from analysis of the spectra, ab initio calculations, as well as chemical intuition, support only one of the two as the structure of the complex. Nuclear quadrupole coupling constants for D-containing species show no evidence of electric field gradient perturbation and are consistent with the structures obtained from inertial data. The primary interaction between the two molecules is a 2.646(11)Å hydrogen bond with acetylene as the donor and a 1,1-difluoroethylene fluorine as the acceptor that forms a 122.41(79)° C–F⋯H angle. A secondary interaction between the acetylenic bond and the difluoroethylene hydrogen atom cis to the acceptor fluorine atom causes the hydrogen bond to deviate 53.25(24)° from linearity. Structural comparisons with the related complex, 1,1-difluoroethylene-hydrogen chloride [Z. Kisiel et al., J. Chem. Soc., Faraday Trans. 88, 3385 (1992)], suggest that the hydrogen bond in the acetylene complex is weaker, whereas comparisons with vinyl fluoride-acetylene [G. C. Cole and A. C. Legon, Chem. Phys. Lett. 369, 31 (2003)] indicate that the fluorine atoms in 1,1-difluoroethylene are less basic than the one in vinyl fluoride.
Distribution and conservation status of the rare plants Melaleuca triumphalis and Stenostegia congesta (Myrtaceae), Victoria River district, northern Australia
Authors: Crase Beth , Cowie Ian D. , Michell Carrie R.
Published: October 2006

Targeted searches of approximately 150 km of cliff lines for two rare sandstone shrubs, Melaleuca triumphalis Craven and Stenostegia congesta A.R.Bean, thought to be restricted to the Victoria River gorge system within Gregory National Park, increased the number of known populations from 3 and 6 to 31 and 37, respectively. Both species occur predominantly in rocky and often fire-protected niches on sandstone cliffs and scree slopes, and are frequently associated with permanent drip-lines and seepage areas. Although their broad habitat requirements are similar, the two species do occur in slightly different niches. The data presented here suggest that M. triumphalis is reasonably fire tolerant, whereas S. congesta appears to be more fire sensitive. Weeds and introduced animals are not thought to pose a threat to these rare species. Models developed using remotely sensed and landscape-scale data (digital elevation models, radiometrics, geology and distance to rivers and streams) suggest that these species may also occur outside Gregory National Park in other areas of the Northern Territory such as on Bullo River and Bradshaw stations and in Keep River National Park. It is suggested that both species be regarded as Vulnerable under the IUCN guidelines.
Austrobasidium, a new gall-forming genus of Exobasidiaceae (Exobasidiales, Basidiomycota) on Hydrangea serratifolia from Chile
Authors: Palfner Götz
Published: October 2006

Austrobasidium pehueldeni gen. & sp. nov. is described on Hydrangea serratifolia (H. et A.) F. Phil. from Chile. This study adds to the very few reports of Exobasidiales causing formation of stem galls and presents the first species known to parasitise a woody epiphyte and member of Hydrangeaceae (Cornales). A. pehueldeni is compared to the morphologically very similar Laurobasidium lauri (Geyler) Jülich and the systematic position of both species is discussed.
Species limits in Carpha (Schoeneae, Cyperaceae) based on phenetic analyses
Authors: Zhang Xiufu , Wilson Karen L. , Bruhl Jeremy J.
Published: October 2006

We review the taxonomic history of Carpha. Recent estimates of the number of species in Carpha have varied from 4 to 15. The generic limits of Carpha and some species limits within Carpha have been uncertain. This study tests the limits of species in Carpha sensu lato by phenetic analyses of morphological data and identifies 16 species. Three of them (Carpha cf. bracteosa C.B.Clarke, C. discolor ms and C. ulugurensis ms) are new; the taxonomic ranks of C. angustissima Cherm., C. capitellata (Nees) Boeck. var. bracteosa (C.B.Clarke) Kük., C. nivicola F.Muell. and C. schoenoides Banks et Sol. ex Hook.f. are clarified; C. perrieri Cherm. is synonymised with C. capitellata (Nees) Boeck.; the definitions of C. schlechteri C.B.Clarke and C. glomerata (Thunb.) Nees are amended.
Cdc42 deficiency causes Sonic hedgehog-independent holoprosencephaly
Authors: Chen Lei , Liao Guanghong , Yang Linda , Campbell Kenneth , Nakafuku Masato , Kuan Chia-Yi , Zheng Yi
Published: October 2006

The telencephalic neuroepithelium (NE) of mammalian brain has an apical-basal polarity that is marked by the positioning of neural progenitors and adherens junctions on the apical/ventricular surface and the ascending of radial glia/progenitor fibers toward the pial/basal surface. The signaling pathway that establishes this apical-basal polarity of NE is not completely understood, but the Rho-family GTPase Cdc42 may play a critical role because it controls cadherin-based intercellular junctions and cell polarity in many species. Here, we tested this hypothesis by a conditional gene-targeting strategy by using the Foxg1-Cre line to delete Cdc42 in the telencephalic neural progenitors in mouse embryos. We found that Cdc42-deletion abolishes the apical localization of PAR6, aPKC, E-cadherin, β-catenin, and Numb proteins in the NE, and severely impairs the extension of nestin-positive radial fibers. Consequently, neural progenitors were scattered throughout the entire depth of the NE, and the Cdc42-deficient telencephalon failed to bulge or separate into two cerebral hemispheres, resulting in holoprosencephaly. However, neither the midline expression of Sonic hedgehog nor the dorso-ventral patterning of the telencephalon was affected by Cdc42-deletion. Taken together, these results indicate that Cdc42 has an essential role in establishing the apical-basal polarity of the telencephalic NE, which is needed for the expansion and bifurcation of cerebral hemispheres.
Monitoring intermediate filament assembly by small-angle x-ray scattering reveals the molecular architecture of assembly intermediates
Authors: Sokolova Anna V. , Kreplak Laurent , Wedig Tatjana , Mücke Norbert , Svergun Dmitri I. , Herrmann Harald , Aebi Ueli , Strelkov Sergei V.
Published: October 2006

Intermediate filaments (IFs), along with microtubules, microfilaments, and associated cross-bridging proteins, constitute the cytoskeleton of metazoan cells. While crystallographic data on the dimer representing the elementary IF “building block” have recently become available, little structural detail is known about both the mature IF architecture and its assembly pathway. Here, we have applied solution small-angle x-ray scattering to investigate the
in vitro
assembly of a 53-kDa human IF protein vimentin at pH 8.4 by systematically varying the ionic strength conditions, and complemented these experiments by electron microscopy and analytical ultracentrifugation. While a vimentin solution in 5 mM Tris·HCl (pH 8.4) contains predominantly tetramers, addition of 20 mM NaCl induces further lateral assembly evidenced by the shift of the sedimentation coeficient and yields a distinct octameric intermediate. Four octamers eventually associate into unit-length filaments (ULFs) that anneal longitudinally. Based on the small-angle x-ray scattering experiments supplemented by crystallographic data and additional structural constraints, 3D molecular models of the vimentin tetramer, octamer, and ULF were constructed. Within each of the three oligomers, the adjacent dimers are aligned exclusively in an approximately half-staggered antiparallel A
11
mode with a distance of 3.2–3.4 nm between their axes. The ULF appears to be a dynamic and a relatively loosely packed structure with a roughly even mass distribution over its cross-section.