bluuebunny/crossref_metadata_2025 huggingface dataset:
Phase referencing VLBI astrometry observation system: VERA
Authors: Kobayashi H. , Kawaguchi N. , Manabe S. , Shibata K. M. , Honma M. , Tamura Y. , Kameya O. , Hirota T. , Jike T. , Imai H. , Omodaka T.
Published: July 2008

VERA aims at astrometric observations using phase referencing VLBI techniques, whose goal is a 10 micro arc-second accuracy for annual parallax measurements. VERA has four 20-m diameter VLBI radio telescopes in Japanese archipelago with the maximum baseline length of 2,300 km. They have the two-beam observing system, which makes simultaneous observations of two objects possible. This leads to very accurate phase referencing VLBI observations. An important science goal is to make a 3-dimensional map of the Galaxy and reveal its dynamics. In order to achieve this, VERA has the 22GHz and 43GHz bands for H2O and SiO maser objects, respectively. Maser objects are compact and suitable for astrometry observations. VERA's construction was started in 2000 and the array became operational in 2004. We have already measured annual parallaxes and proper motions of some galactic objects. In the future, VERA will collaborate with Korean and Chinese VLBI stations.
Astrometry of Galactic star-forming regions with VERA
Authors: Honma M. , Bushimata T. , Choi Y. K. , Hirota T. , Imai H. , Iwadate K. , Jike T. , Kameno S. , Kameya O. , Kamohara R. , Kan-ya Y. , Kawaguchi N. , Kijima M. , Kim M. K. , Kobayashi H. , Kuji S. , Kurayama T. , Manabe S. , Matsumoto N. , Miyaji T. , Nagayama T. , Nakagawa A. , Nakamura K. , Oh C.-S. , Omodaka T. , Oyama T. , Sakai S. , Sato K. , Sato M. , Sasao T. , Shibata K. M. , Tamura Y. , Yamashita K.
Published: July 2008

We present an overview of recent astrometric results with VERA. Since 2004, we have been conducting astrometry of tens of Galactic maser sources with VERA, and recently obtained trigonometric parallaxes for several sources, with distances ranging from 180 pc to 5.3 kpc. In this paper, we briefly summarize the results for Galactic star-forming regions, including S269, Orion-KL, NGC 1333, ρ-oph, NGC 281 and others.
The 3-mm flux density monitoring of Sagittarius A* with the ATCA
Authors: Li J. , Shen Z. Q. , Miyazaki A. , Miyoshi M. , Tsutsumi T. , Tsuboi M. , Huang L. , Sault B.
Published: July 2008

We have performed monitoring observations of the 3-mm flux density toward the Galactic center compact radio source Sgr A* with the ATCA since 2005 October. It has been found that during several observing epochs Sgr A* was quite active, showing significant intraday variation. Here we report the detection of an IDV in Sgr A* on 2006 August 13, which exhibits a 27% fractional variation in about 2 hrs.
Astrometric planet searches with SIM PlanetQuest
Authors: Beichman C. A. , Unwin S. C. , Shao M. , Tanner A. M. , Catanzarite J. H. , Marcy G. W.
Published: July 2008

SIM will search for planets with masses as small as the Earth's orbiting in the ‘habitable zones’ around more than 100 of the nearest stars and could discover many dozen if Earth-like planets are common. With a planned “Deep Survey” of 100–450 stars (depending on desired mass sensitivity) SIM will search for terrestrial planets around all of the candidate target stars for future direct detection missions such as Terrestrial Planet Finder and Darwin. SIM's “Broad Survey” of 2100 stars will characterize single and multiple-planet systems around a wide variety of stellar types, including many now inaccessible with the radial velocity technique. In particular, SIM will search for planets around young stars providing insights into how planetary systems are born and evolve with time.
Determination of the barycentric velocity of an astrometric satellite using its own observational data
Authors: Butkevich A. G. , Klioner S. A.
Published: July 2008

The problem of determination of the orbital velocity of an astrometric satellite from its own observational data is studied. It is well known that data processing of microarcsecond-level astrometric observations imposes very stringent requirements on the accuracy of the orbital velocity of satellite (a velocity correction of 1.45 mm/s implies an aberrational correction of 1 μas). Because of a number of degeneracies the orbital velocity cannot be fully restored from observations provided by the satellite. Seven constraints that must be applied on a velocity parameterization are discussed and formulated mathematically. It is shown what part of velocity can be recovered from astrometric data using a combined fit of both velocity parameters and astrometric parameters of the sources. Numerical simulations show that, with the seven constraints applied, the velocity and astrometric parameters can be reliably estimated from observational data. It is also argued that the idea to improve the velocity of an astrometric satellite from its own observational data is only useful if a priori information on orbital velocity justifies the applicability of the velocity constraints. The proposed model takes into account only translational motion of the satellite and ignores any satellite-specific parameters. Therefore, the results of this study are equally applicable to both scanning missions similar to Gaia, and pointing ones like SIM, provided that enough sources were observed sufficiently uniformly.
JStuff - a preliminary extragalactic model for the ESA-Gaia satellite simulation framework
Authors: Krone-Martins A. G. O. , Ducourant C. , Teixeira R. , Luri X.
Published: July 2008

In this work we describe the JStuff, a preliminary generator of mock catalogues of extragalactic objects based on the Stuff code. This version is being implemented in the Java language for the ESA-Gaia satellite simulation framework. We also compare some results obtained with both versions of the simulator.
Simulating Gaia observations and on-ground reconstruction
Authors: Masana E. , Fabricius C. , Torra J. , Portell J. , Catañeda J.
Published: July 2008

On a daily basis the Gaia telemetry data (some 30 GB) must be stored and treated in order to reconstruct the actual observations. This initial data treatment processes all newly arrived telemetry and various pieces of auxiliary data. The first part of the process is merely a reformatting to create raw objects for permanent storage in the raw data base (some 40 TB at the end of the mission). The next part is to analyze the data to derive initial values for the observables, e.g. transit times and fluxes, producing intermediate objects. Finally, the intermediate objects are matched with sources in the data base, linking all the observations of a given source.

To check the initial data treatment algorithm we use simulations of the telemetry stream provided by GASS, the Gaia System Simulator. GASS simulates astrometric, photometric and radial velocity data, using models of the satellite and on-board instruments, as well as the models of different of objects observed by Gaia (stars, galaxies, solar system objects, . . .). On the other hand, the initial data treatment allows us to validate the data generated by GASS, which are used too to check other algorithms like the First Look or the Astrometric Global Iterative Solution (AGIS).
Time transfer by laser link between China and France
Authors: Zhao C. , Ni W. T. , Samain E.
Published: July 2008

To advance from milli-arcsecond to micro-arcsecond astrometry, time keeping capability and its comparison among different stations need to be improved and enhanced. The T2L2 (Time transfer by laser link) experiment under development at OCA and CNES to be launched in 2008 on Jason-2, allows the synchronization of remote clocks on Earth. It is based on the propagation of light pulses in space which is better controlled than propagation of radio waves. In this paper, characteristics are presented for both a common view and non-common view T2L2 comparisons of clocks between China and France.
Deep-space laser-ranging missions ASTROD and ASTROD I for astrodynamics and astrometry
Authors: Ni W. T. ,   the ASTROD I ESA COSMIC VISION 2015-2025 TEAM
Published: July 2008

Deep-space laser ranging will be ideal for testing relativistic gravity, and mapping the solar-system to an unprecedented accuracy. ASTROD (Astrodynamical Space Test of Relativity using Optical Devices) and ASTROD I are such missions. ASTROD I is a mission with a single spacecraft; it is the first step of ASTROD with 3 spacecraft. In this talk, after a brief review of ASTROD and ASTROD I, we concentrate on the precision of solar astrodynamics that can be achieved together with implications on astrometry and reference frame ties. The precise planetary ephemeris derived from these missions together with second post-Newtonian test of relativistic gravity will serve as a foundation for future precise astrometry observations. Relativistic frameworks are discussed from these considerations.
The restoration of the quadrupole light bending
Authors: Crosta M. T. , Gardiol D. , Lattanzi M. G. , Morbidelli R.
Published: July 2008

The ESA astrometric mission Gaia will be able to put to test General Relativity thanks to differential astrometric measurements. The differential experiment, GAREX, implemented in the form of repeated Eddington-like measurement, aims at measuring the quadrupole light bending due to an oblate planet by comparing the evolution of relative distances in stellar fields in the vicinity of it. Simulations which utilize (i) selected fields extracted from the GSCII data base, (ii) a realistic error model as function of the star's magnitude and distance from Jupiter's edge, show the real best scenarios and how to improve the Gaia ability to detect this relativistic effect.
Astrometric data for NEAs extracted from the infrared DENIS survey
Authors: Thuillot W. , Berthier J. , Iglésias J. , Simon G. , Lainey V.
Published: July 2008

When astrometric data can be extracted from archives, this generally allows us to get very strong constraints for the orbital modeling of Solar System objects. This is particularly important for Near-Earth Asteroids. We have developed tools in the Virtual Observatory framework in order to carry out such a task. We have applied them to the DENIS survey. This survey has been performed from 1995 to 2001 in the I, J, K' spectral bands with a 1m telescope at ESO La Silla. Many sources associated to Solar System Objects have been identified and we present our preliminary results.
Worldwide R&D of Virtual Observatory
Authors: Cui C. Z. , Zhao Y. H.
Published: July 2008

Virtual Observatory (VO) is a data intensive online astronomical research and education environment, taking advantages of advanced information technologies to achieve seamless and uniform access to astronomical information. The concept of VO was introduced in the late 1990s to meet the challenges brought up with data avalanche in astronomy. In the paper, current status of International Virtual Observatory Alliance, technical highlights from world wide VO projects are reviewed, a brief introduction of Chinese Virtual Observatory is given.
Spiritual Values, Religious Practices, and Democratic Attitudes
Authors: Kim Myunghee
Published: June 2008

Using data from the 1999–2001 World Values and European Values Surveys, this article examines the impact of spiritual values and religious practices on democratic attitudes in twenty countries throughout Western Europe, North America, South America, Asia, and Africa. I assume that a reciprocal interaction between national conditions and individual orientations shapes support for democracy. Religious commitment as theological orthodoxy and attendance at religious services does not strengthen democratic views. Instead, explicitly political and cultural variables explain approval for democratic principles, particularly among industrialized countries. Individuals who express a low fear of threatening groups also back democratic institutions, regardless of a nation's industrialization. Among religious affiliations, Protestants in developing countries advocate democratic values. So do Muslims in industrialized countries. Nonmembers of religious institutions, however, are less likely to uphold democratic attitudes.
Der „Berkeley Expressivity Questionnaire”
Authors: Mohiyeddini Changiz , John Oliver , Gross James J.
Published: July 2008

Zusammenfassung. Vorgestellt wird eine deutsche Adaption des „Berkeley Expressivity Questionnaire” (BEQ; Gross & John, 1995 ). Das Instrument erfasst mit Hilfe von 16 Items ökonomisch drei Dimensionen der Expressivität: Negative Expressivität, Positive Expressivität und Impulsintensität. In Studie 1 (n = 385) wurden mittels konfirmatorischer Faktorenanalyse die interne faktorielle Struktur und die psychometrischen Eigenschaften für die Faktoren des BEQ bestimmt. In einer Längsschnittstudie (Studie 2) wurden die Stabilität und Validität des BEQ untersucht: Zum ersten Messzeitpunkt wurde die selbstberichtete Expressivität von 220 Probanden erhoben. Zum zweiten Messzeitpunkt (sechs Monate später) wurden neben der selbstberichteten Expressivität für jeden Probanden zwei Fremdurteile sowie globale Maße der Persönlichkeit, positive und negative Affektivität und Maße der physischen und psychischen Gesundheit erfasst. Die Dimensionen des BEQ sind zeitlich stabil und positiv mit den Fremdurteilen korreliert. Negative Expressivität und Impulsintensität sind mit Neurotizismus, negativer Affektivität, physischen Beschwerden und Depressivität verbunden. Positive Expressivität ist mit Extraversion, Offenheit und positiver Affektivität assoziiert. Frauen zeigen im Vergleich zu Männern höhere Werte in allen Dimensionen des BEQ, welche mit Alter negativ korreliert sind.
History of Childhood Abuse and Neglect and Suicidal Behavior at Hospital Admission
Authors: Sfoggia Ana , Pacheco Marco Antonio , Grassi-Oliveira Rodrigo
Published: July 2008

Suicide is a major public health problem. Preventive measures have been sought by identifying risk factors. This study evaluates the association of childhood abuse and neglect with suicidal behavior at the time of psychiatric hospital admission. A total of 120 subjects (72 females; mean age 42.5 ± 15.6 years old) admitted from August 2006 to July 2007 completed the Childhood Trauma Questionnaire (CTQ) to assess severity of exposure to childhood maltreatment. Thereof 62 (51.6%) patients presented with suicidal behavior at admission. Patients who had attempted suicide had significantly higher CTQ scores. Regression analysis indicated that shorter illness duration and severity of childhood maltreatment were predictors of suicidal behavior at admission. The study showed that inpatients of a psychiatric unit of a general hospital who experienced severe childhood abuse or neglect were significantly more likely to present with suicidal behavior. History of childhood maltreatment should be evaluated as an associated risk factor of suicidal behavior at admission of psychiatric inpatients.
A 40Ar/39Ar study of oceanic and continental deformation processes during an oblique collision: Taconian orogeny in the Quebec reentrant of the Canadian Appalachians
Authors: Malo Michel , Ruffet Gilles , Pincivy Alix , Tremblay Alain
Published: June 2008

Two phases of penetrative deformation are documented in the Taconian hinterland of the Appalachian orogen in the Gaspé Peninsula. D1 is associated with the obduction of the Mont‐Albert ophiolite onto the Paleozoic Laurentian margin, whereas D2 corresponds to later transport of allochthons across the margin. In the metamorphic sole, S1 is a SE‐dipping mylonitic fabric with a downdip lineation. In underlying metabasalts, D1 is characterized by NW‐overturned and recumbent folds, and a subhorizontal S1 schistosity with an ENE‐trending orogen‐parallel lineation. D2 is characterized by a S2 steeply dipping penetrative axial‐planar crenulation cleavage and NE‐trending F2 folds. The intraoceanic thrusting of ophiolite is dated at 465 Ma (early D1) whereas emplacement of ophiolite and subsequent deformation of the margin was recorded by isotopic signatures between 459 and 456 Ma (late D1). D2 is dated at 448 Ma throughout the hinterland. Taconian transpressive deformation is related to an oblique collision within the Quebec reentrant of the Canadian Appalachians during the Ordovician.
Three‐dimensional seismic imaging of the Blake Ridge methane hydrate province: Evidence for large, concentrated zones of gas hydrate and morphologically driven advection
Authors: Hornbach Matthew J. , Saffer Demian M. , Holbrook W. Steven , Van Avendonk Harm J. A. , Gorman Andrew R.
Published: June 2008

Current estimates for the amount of methane trapped below gas hydrate provinces remain highly speculative, and explanations for how this methane is injected into the atmosphere are wide‐ranging and unverified. Blake Ridge, one of the largest passive margin gas hydrate provinces on Earth, is traditionally characterized as an expansive yet dilute reservoir of methane hydrate with no significant fluid advection. Previous 2‐D seismic analysis and Ocean Drilling Program Leg 164 drilling results show evidence for both concentrated zones of hydrate and possible fluid flow; however, the extent of these phenomena remains ambiguous. Here we analyze high‐resolution 3‐D seismic data collected at Blake Ridge in 2000 and map seismic indicators of concentrated hydrate and fluid flow. We also use the seismic data to map the base of the gas hydrate stability in 3‐D. Our analysis demonstrates that the gas hydrate phase boundary varies significantly in areas of high sedimentation and erosion, suggesting a dynamic hydrate system. Furthermore, evidence of localized bottom‐simulating reflector shoaling, particularly at a sediment wave bounding surface, indicates ongoing advection. The analysis reveals that the Blake Ridge gas hydrate system is significantly more dynamic than previous studies suggest, and we hypothesize that fluctuating sedimentation and erosion patterns cause hydrate phase‐boundary instability that triggers fluid flow.
Cross‐shore suspended sand and bed load transport on beaches
Authors: Kobayashi Nobuhisa , Payo Andres , Schmied Lauren
Published: June 2008

Simple formulas are developed to predict the time‐averaged rates of cross‐shore suspended sand and bed load transport. The net suspended sand transport rate is expressed as the product of the depth‐averaged current and the suspended sediment volume per unit bottom area with a reduction factor that accounts for the correlation between the time‐varying fluid velocity and sediment concentration. The net bed load transport rate under nonlinear waves is assumed to be onshore and proportional to σU3 where σU is the standard deviation of the horizontal velocity. The probabilities of sediment movement and suspension are introduced to account for the initiation of sediment movement and suspension. Simple functions are proposed to account for the effects of a steep bottom slope on the bed load and suspended sediment transport rates. The proposed formulas are found to be in agreement with three data sets within a factor of about 2. The proposed formulas are shown to be consistent with existing simple formulas. The formulas are incorporated into a time‐averaged wave model and the continuity equation of bottom sediment to predict the beach profile evolution. The numerical model is compared with seven small‐scale tests including berm erosion tests and seven large‐scale tests including dune erosion tests. The numerical model predicts the overall beach profile evolution including the berm and dune erosion but does not always predict the fairly subtle profile changes including bar migration accurately.
Arctic sea ice variability and trends, 1979–2006
Authors: Parkinson Claire L. , Cavalieri Donald J.
Published: June 2008

Analysis of Arctic sea ice extents derived from satellite passive‐microwave data for the 28 years 1979–2006 yields an overall negative trend of −45,100 ± 4,600 km2/a (−3.7 ± 0.4%/decade) in the yearly averages, with negative ice extent trends also occurring for each of the four seasons and each of the 12 months. For the yearly averages, the largest decreases occur in the Kara and Barents seas and the Arctic Ocean, with linear least squares slopes of −10,600 ± 2,800 km2/a (−7.4 ± 2.0%/decade) and −10,100 ± 2,200 km2/a (−1.5 ± 0.3%/decade), respectively, followed by Baffin Bay/Labrador Sea, with a slope of −8000 ± 2000 km2/a (−9.0 ± 2.3%/decade), the Greenland Sea, with a slope of −7000 ± 1400 km2/a (−9.3 ± 1.9%/decade), and Hudson Bay, with a slope of −4500 ± 900 km2/a (−5.3 ± 1.1%/decade). These are all statistically significant decreases at a 99% confidence level. The seas of Okhotsk and Japan also have a statistically significant ice decrease, although at a 95% confidence level, and the three remaining regions, the Bering Sea, Canadian Archipelago, and Gulf of St. Lawrence, have negative slopes that are not statistically significant. The 28‐year trends in ice areas for the Northern Hemisphere total are also statistically significant and negative in each season, each month, and for the yearly averages.
Regularizing kernel‐based BRDF model inversion method for ill‐posed land surface parameter retrieval using smoothness constraint
Authors: Wang Yanfei , Yang Changchun , Li Xiaowen
Published: June 2008

In this paper, we consider the problem how to solve the kernel‐based bidirectional reflectance distribution function (BRDF) models for the retrieval of land surface albedos. The above problem is an ill‐posed inverse problem. We will employ a new regularization technique to alleviate the ill‐posedness. The Tikhonov regularization has been discussed for BRDF model inversion, however, much study has to be done before applying it in practice (Wang et al., 2007). In this paper, we thoroughly investigate this method, and propose a discrepancy method for a posteriori choice of the regularization parameter and several options for choosing the regularizing stabilizer. The proposed method can alleviate difficulties in numerical computation when the discrete kernel is badly conditioned and the number of observations is poor. Applying the proposed method can always find a set of suitable BRDF coefficients for poorly sampled data. The proposed method is an improvement of the traditional least squares error algorithm in AMBRALS (Algorithm for MODIS (Moderate Resolution Imaging Spectroradiometer) Bidirectional Reflectance Anisotropies of the Land Surface), see Strahler et al. (1999), and is comparable to the regularized singular value decomposition method developed by Wang et al. (2007). Hence the proposed method can be considered as a supplemental algorithm for the robust estimation of the land surface BRDF/albedos. Numerical performance is given in this paper for the widely used field‐based 18 data sets among the 73 data sets (see Li et al., 2001) and for the satellite data.
Ferric oxides in East Candor Chasma, Valles Marineris (Mars) inferred from analysis of OMEGA/Mars Express data: Identification and geological interpretation
Authors: Le Deit Laetitia , Le Mouélic Stéphane , Bourgeois Olivier , Combe Jean‐Philippe , Mège Daniel , Sotin Christophe , Gendrin Aline , Hauber Ernst , Mangold Nicolas , Bibring Jean‐Pierre
Published: June 2008

The mineralogical composition of the Martian surface is constrained by analyzing the data of the OMEGA visible and near infrared imaging spectrometer onboard Mars Express. Ferric signatures had previously been reported in Valles Marineris, Margaritifer Terra, and Terra Meridiani. Here we use three independent data reduction methods (Spectral Angle Mapper, a modified Spectral Mixture Analysis and Modified Gaussian Model) to detect and map ferric oxides in East Candor Chasma, a part of Valles Marineris. Ferric oxides in East Candor Chasma are concentrated in scattered formations. MOLA altimetry indicates that the ferric oxides are preferentially located in topographic lows. THEMIS, HRSC and MOC images show that the ferric oxide spectral signatures are systematically correlated with superficial deposits of low albedo, located at the foot of, or resting on Interior Layered Deposits (ILDs). This spatial distribution suggests that ferric oxides are genetically linked to ILDs. Gravity and wind‐driven remobilization of ferric oxides previously formed in the ILDs can explain their accumulation around the ILDs.
A comparative modeling analysis of multiscale temporal variability of rainfall in Australia
Authors: Samuel Jos M. , Sivapalan Murugesu
Published: June 2008

The effects of long‐term natural climate variability and human‐induced climate change on rainfall variability have become the focus of much concern and recent research efforts. In this paper, we present the results of a comparative analysis of observed multiscale temporal variability of rainfall in the Perth, Newcastle, and Darwin regions of Australia. This empirical and stochastic modeling analysis explores multiscale rainfall variability, i.e., ranging from short to long term, including within‐storm patterns, and intra‐annual, interannual, and interdecadal variabilities, using data taken from each of these regions. The analyses investigated how storm durations, interstorm periods, and average storm rainfall intensities differ for different climate states and demonstrated significant differences in this regard between the three selected regions. In Perth, the average storm intensity is stronger during La Niña years than during El Niño years, whereas in Newcastle and Darwin storm duration is longer during La Niña years. Increase of either storm duration or average storm intensity is the cause of higher average annual rainfall during La Niña years as compared to El Niño years. On the other hand, within‐storm variability does not differ significantly between different ENSO states in all three locations. In the case of long‐term rainfall variability, the statistical analyses indicated that in Newcastle the long‐term rainfall pattern reflects the variability of the Interdecadal Pacific Oscillation (IPO) index, whereas in Perth and Darwin the long‐term variability exhibits a step change in average annual rainfall (up in Darwin and down in Perth) which occurred around 1970. The step changes in Perth and Darwin and the switch in IPO states in Newcastle manifested differently in the three study regions in terms of changes in the annual number of rainy days or the average daily rainfall intensity or both. On the basis of these empirical data analyses, a stochastic rainfall time series model was developed that incorporates the entire range of multiscale variabilities observed in each region, including within‐storm, intra‐annual, interannual, and interdecadal variability. Such ability to characterize, model, and synthetically generate realistic time series of rainfall intensities is essential for addressing many hydrological problems, including estimation of flood and drought frequencies, pesticide risk assessment, and landslide frequencies.
Environmental Education Television Episodes
Authors: Peterson Jane , Seielstad George
Published: June 2008

“Our Changing Planet” is a series of 90‐second television episodes whose purpose is to enhance public understanding of the global environment and the changes it is undergoing. The hope is that with this deeper understanding, people will appreciate the need to modify behaviors that produce negative environmental effects.

The episodes are produced by the Upper Midwest Aerospace Consortium at the University of North Dakota, Grand Forks, with partial funding from NASA. To date, 40 episodes have been created and distributed to 46 public television stations across the United States by the National Educational Telecommunications Association.
O'Hara Receives 2007 Harry H. Hess Medal
Authors: Niu Yaoling , O'Hara Michael John
Published: June 2008

The Harry H. Hess Medal recognizes “outstanding achievements in research in the constitution and evolution of Earth and other planets.” It is thus most appropriate that Mike O'Hara receive the 2007 Hess Medal of the American Geophysical Union.

Mike started as a field geologist studying the Scourie Gneisses in Scotland. As a pioneer, Mike used experimental petrology to study the petrogenesis of mantle rocks and rocks derived from the mantle that build the ocean crust. Mike's talent is also marked by his insights into the petrogenesis of lunar basalts. It is fair to say that modern igneous petrology and geochemistry would not be the same without Mike's many discoveries, creative efforts, and deep insights.
Lunar science research proposals sought
Authors: Showstack Randy
Published: June 2008

NASA's Science Mission Directorate, in cooperation with the agencys Exploration Systems Mission Directorate, is seeking research projects for the NASA Lunar Science Institute. According to the notice, proposals “should include broadly based investigations of the highest quality that address lunar science objectives” and also should align with the institute's goals and objectives. Notices of intent are due 27 June 2008, and proposals are due 29 August 2008.
Ecosystem sciences working group
Authors: Showstack Randy
Published: June 2008

The Science Advisory Board of the U.S. National Oceanic and Atmospheric Administration (NOAA) is soliciting nominations for its Ecosystem Sciences and Management Working Group, which provides scientific advice and broad direction on NOAA's ecosystem‐related programs. The board seeks nominees in disciplines related to ecosystem sciences and management: social science, oceanography, living marine resources, sampling and remote sensing, and modeling.
Beyond Brainstorming: Exploring Climate Change Adaptation Strategies: Climate Change Adaptation for Water Managers; Oracle, Arizona, 4–5 February 2008
Authors: Garfin Gregg , Jacobs Katharine , Buizer James
Published: June 2008

The most visible manifestation of climate change in the American Southwest is its effects on water resources. Since 1999, the region's water supplies and major rivers have been tested by burgeoning population growth and drought. Model projections suggest increasing drought severity and duration due to rising temperatures, increased evapotranspiration, and enhanced atmospheric circulation from the tropics (Hadley circulation).

The Arizona Water Institute, Arizona State University, and University of Arizona convened a “knowledge network” of local, state, tribal, and federal water resources managers and scientists to identify climate change adaptation and response strategies.
Ocean Environment and Fisheries
Authors: Miller Arthur J.
Published: June 2008

Very few marine fisheries assessments use oceanic environmental information when estimating stocks for management purposes, exceptions being assessments of California sardines and northern Australian prawns, which use sea surface temperature. Instead, assessments are based on trends and indices of abundance, biomass, age composition, size at age, maturity, and so forth, as indicators of the health and trajectory of fish stocks. Recently, there have been many attempts to better understand the impact of the spatial and temporal variations of the physical ocean state on fish populations and to consequently enhance the efficacy of these stock assessments.
Gulf of Mexico hypoxia plan
Authors: Showstack Randy
Published: June 2008

On 16 June, the Mississippi River/Gulf of Mexico Watershed Nutrient Task Force released an action plan to reduce, mitigate, and control hypoxia in the northern Gulf of Mexico. The plan builds upon a 2001 plan by including more accountability through an annual operating plan, better tracking of progress, and state and federal nutrient reduction strategies. “Our improved plan unites governments and citizens across the country to take action upstream and along the coast to reduce river nutrient pollution and increase Gulf of Mexico health,” said U.S. Environmental Protection Agency assistant administrator for water Benjamin Grumbles.
Astronomer honored with a mineral
Authors: Showstack Randy
Published: June 2008

“I have always been very intrigued by minerals, so it is great to be one,” commented NASA Stardust mission principal investigator and University of Washington astronomer Donald Brownlee, AGU member, after learning the International Mineralogical Association had named a new mineral in his honor. Brownleeite, a combination of manganese and silicon, is the first mineral discovered in a particle from a comet. The mineral was found inside a particle collected by a high‐altitude NASA aircraft from a dust stream that entered Earth's atmosphere in 2003.
Controlling Hypoxia on the U.S. Louisiana Shelf: Beyond the Nutrient‐Centric View
Authors: Bianchi Thomas S. , Dimarco Steven F. , Allison Mead A. , Chapman Piers , Cowan James H. , Hetland Robert D. , Morse John W. , Rowe Gil
Published: June 2008

As the Earth's population continues to increase, the projected effects of contaminant loading and human encroachment on biodiversity remain unclear. One area of intense interest is coastal eutrophication and associated hypoxia events (with hypoxia defined as oxygen <2 milligrams per liter = 1.4 milliliters per liter = ˜63 micromoles per cubic decimeter). On average, the Mississippi River discharges to the northern Gulf of Mexico (GOM) 550 cubic kilometers of freshwater and approximately 60–70×109 moles of dissolved inorganic nitrogen per year [Dagg et al., 2004], which contains anthropogenic nitrogen derived primarily from agricultural fertilizer as well as effluent from animal feedlots.
Geographic Uncertainty in Environmental Security
Authors: Ahlquist Jon
Published: June 2008

This volume contains 17 papers presented at the NATO Advanced Research Workshop on Fuzziness and Uncertainty held in Kiev, Ukraine, 28 June to 1 July 2006. Eleven of the papers deal with fuzzy set concepts, while the other six (papers 5, 7, 13, 14, 15, and 16) are not fuzzy. A reader with no prior exposure to fuzzy set theory would benefit from having an introductory text at hand, but the papers are accessible to a wide audience. In general, the papers deal with broad issues of classification and uncertainty in geographic information.
Revised Pacific‐Antarctic plate motions and geophysics of the Menard Fracture Zone
Authors: Croon Marcel B. , Cande Steven C. , Stock Joann M.
Published: June 2008

A reconnaissance survey of multibeam bathymetry and magnetic anomaly data of the Menard Fracture Zone allows for significant refinement of plate motion history of the South Pacific over the last 44 million years. The right‐stepping Menard Fracture Zone developed at the northern end of the Pacific‐Antarctic Ridge within a propagating rift system that generated the Hudson microplate and formed the conjugate Henry and Hudson Troughs as a response to a major plate reorganization ∼45 million years ago. Two splays, originally about 30 to 35 km apart, narrowed gradually to a corridor of 5 to 10 km width, while lineation azimuths experienced an 8° counterclockwise reorientation owing to changes in spreading direction between chrons C13o and C6C (33 to 24 million years ago). We use the improved Pacific‐Antarctic plate motions to analyze the development of the southwest end of the Pacific‐Antarctic Ridge. Owing to a 45° counterclockwise reorientation between chrons C27 and C20 (61 to 44 million years ago) this section of the ridge became a long transform fault connected to the Macquarie Triple Junction. Following a clockwise change starting around chron C13o (33 million years ago), the transform fault opened. A counterclockwise change starting around chron C10y (28 millions years ago) again led to a long transform fault between chrons C6C and C5y (24 to 10 million years ago). A second period of clockwise reorientation starting around chron C5y (10 million years ago) put the transform fault into extension, forming an array of 15 en echelon transform faults and short linking spreading centers.
VLF wave generation by amplitude‐modulated HF heater waves at Gakona, Alaska
Authors: Kuo Spencer P. , Wu Yen‐Liang , Pradipta R. , Cohen J. A. , Lee M. C.
Published: June 2008

Experiments conducted at Gakona, Alaska, using the intensity‐modulated HF heating waves to interact with electrojet currents for the generation of VLF waves, are reported. An unexpected large increasing rate from 4 to 8 kHz in the frequency dependency of the VLF radiation intensity was observed. The peak value at 8 kHz was intense (about 7.5 dB above that of the 2 kHz signal used as a marker) and the wave intensity from 5 to 17 kHz appeared to be abnormally high (i.e., stronger than that at 2 kHz). In the experiments, we also observed the enhancement of spread‐E irregularities at electrojet current altitudes due to the amplitude‐modulated heater wave. These results and theoretical analyses suggest that temporally modulated electrojet currents mix with heater wave‐excited density irregularities to form whistler mode currents, which generate VLF whistler waves directly with much larger intensities and better directivity than a Hertzian dipole can.
Accumulation of atmospheric sulfur in some Costa Rican soils
Authors: Bern Carleton R. , Townsend Alan R.
Published: June 2008

Sulfur is one of the macronutrient elements whose sources to terrestrial ecosystems should shift from dominance by rock‐weathering to atmospheric deposition as soils and underlying substrate undergo progressive weathering and leaching. However, the nature and timing of this transition is not well known. We investigated sources of sulfur to tropical rain forests growing on basalt‐derived soils in the Osa Peninsula region of Costa Rica. Sulfur sources were examined using stable isotope ratios (δ34S) and compared to chemical indices of soil development. The most weathered soils, and the forests they supported, are dominated by atmospheric sulfur, while a less weathered soil type contains both rock‐derived and atmospheric sulfur. Patterns of increasing δ34S with increasing soil sulfur concentration across the landscape suggest atmospheric sulfur is accumulating, and little rock‐derived sulfur has been retained. Soil sulfur, minus adsorbed sulfate, is correlated with carbon and nitrogen, implying that sulfur accumulation occurs as plants and microbes incorporate sulfur into organic matter. Only the lower depth increments of the more weathered soils contained significant adsorbed sulfate. The evidence suggests a pattern of soil development in which sulfur‐bearing minerals in rock, such as sulfides, weather early relative to other minerals, and the released sulfate is leached away. Sulfur added via atmospheric deposition is retained as organic matter accumulates in the soil profile. Adsorbed sulfate accumulates later, driven by changes in soil chemistry and mineralogy. These aspects of sulfur behavior during pedogenesis in this environment may hasten the transition to dominance by atmospheric sources.
Identification and pharmacological characterization of the prostaglandin FP receptor and FP receptor variant complexes
Authors: Liang Y , Woodward D F , Guzman V M , Li C , Scott D F , Wang J W , Wheeler L A , Garst M E , Landsverk K , Sachs G , Krauss A H‐P , Cornell C , Martos J , Pettit S , Fliri H
Published: June 2008

Background and purpose:A prostamide analogue, bimatoprost, has been shown to be effective in reducing intraocular pressure, but its precise mechanism of action remains unclear. Hence, to elucidate the molecular mechanisms of this effect of bimatoprost, we focused on pharmacologically characterizing prostaglandin FP receptor (FP) and FP receptor variant (altFP) complexes.

Experimental approach:FP receptor mRNA variants were identified by reverse transcription‐polymerase chain reaction. The FP‐altFP4 heterodimers were established in HEK293/EBNA cells co‐expressing FP and altFP4 receptor variants. A fluorometric imaging plate reader was used to study Ca2+mobilization. Upregulation of cysteine‐rich angiogenic protein 61 (Cyr61) mRNA was measured by Northern blot analysis, and phosphorylation of myosin light chain (MLC) by western analysis.

Key results:Six splicing variants of FP receptor mRNA were identified in human ocular tissues. Immunoprecipitation confirmed that the FP receptor is dimerized with altFP4 receptors in HEK293/EBNA cells co‐expressing FP and altFP4 receptors. In the studies of the kinetic profile for Ca2+mobilization, prostaglandin F2α(PGF2α) elicited a rapid increase in intracellular Ca2+followed by a steady state phase. In contrast, bimatoprost elicited an immediate increase in intracellular Ca2+followed by a second phase. The prostamide antagonist, AGN211335, selectively and dose‐dependently inhibited the bimatoprost‐initiated second phase of Ca2+mobilization, Cyr61 mRNA upregulation and MLC phosphorylation, but did not block the action of PGF2α.

Conclusion and implications:Bimatoprost lacks effects on the FP receptor but may interact with the FP‐altFP receptor heterodimer to induce alterations in second messenger signalling. Hence, FP‐altFP complexes may represent the underlying basis of bimatoprost pharmacology.

British Journal of Pharmacology(2008)154, 1079–1093; doi:10.1038/bjp.2008.142; published online 21 April 2008
Lapaquistat acetate, a squalene synthase inhibitor, changes macrophage/lipid‐rich coronary plaques of hypercholesterolaemic rabbits into fibrous lesions
Authors: Shiomi M , Yamada S , Amano Y , Nishimoto T , Ito T
Published: June 2008

Background and purpose:

Inhibition of squalene synthesis could transform unstable, macrophage/lipid‐rich coronary plaques into stable, fibromuscular plaques. We have here treated WHHLMI rabbits, a model for coronary atherosclerosis and myocardial infarction, with a novel squalene synthase inhibitor, lapaquistat acetate (TAK‐475).

Experimental approach:

Young male WHHLMI rabbits were fed a diet supplemented with lapaquistat acetate (100 or 200 mg per kg body weight per day) for 32 weeks. Serum lipid levels were monitored every 4 weeks. After the treatment, lipoprotein lipid and coenzyme Q10 levels were assayed, and coronary atherosclerosis and xanthomas were examined histopathologically or immunohistochemically. From histopathological and immunohistochemical sections, the composition of the plaque was analysed quantitatively with computer‐assisted image analysis. Xanthoma was evaluated grossly.

Key results:

Lapaquistat acetate decreased plasma cholesterol and triglyceride levels, by lowering lipoproteins containing apoB100. Development of atherosclerosis and xanthomatosis was suppressed. Accumulation of oxidized lipoproteins, macrophages and extracellular lipid was decreased in coronary plaques of treated animals. Treatment with lapaquistat acetate increased collagen concentration and transformed coronary plaques into fibromuscular plaques. Lapaquistat acetate also suppressed the expression of matrix metalloproteinase‐1 and plasminogen activator inhibitor‐1 in the plaque and increased peripheral coenzyme Q10 levels. Increased coenzyme Q10 levels and decreased very low‐density lipoprotein cholesterol levels were correlated with improvement of coronary plaque composition.

Conclusion and implications:

Inhibition of squalene synthase by lapaquistat acetate delayed progression of coronary atherosclerosis and changed coronary atheromatous plaques from unstable, macrophage/lipid accumulation‐rich, lesions to stable fibromuscular lesions.

British Journal of Pharmacology (2008) 154, 949–957; doi:10.1038/bjp.2008.143; published online 21 April 2008
Regulation of M2‐type pyruvate kinase mediated by the high‐affinity IgE receptors is required for mast cell degranulation
Authors: Ryu H , Walker J K L , Kim S , Koo N , Barak L S , Noguchi T , Kang B Y , Kim K‐M
Published: June 2008

Background and purpose:

M2‐type pyruvate kinase (M2PK) was found to interact directly with the ‘ITAM’ region of the γ chain of the high‐affinity IgE receptor (FcɛRI). Our hypothesis was that mast cell degranulation might require the FcɛRI‐mediated inhibition of M2PK activity.

Experimental approach:

In rat basophilic leukaemia (RBL‐2H3) cells, the effects of directly inhibiting M2PK or preventing the FcɛRI‐mediated inhibition of M2PK (disinhibition) on degranulation was measured by hexosaminidase release. Effects of blocking the FcɛRI‐mediated inhibition of M2PK was also assessed in vivo in a mouse model of allergen‐induced airway hyper‐responsiveness.

Key results:

Activation of FcɛRI in RBL‐2H3 cells caused the rapid phosphorylation of tyrosine residues in M2PK, associated with a decrease in M2PK enzymatic activity. There was an inverse correlation between M2PK activity and mast cell degranulation. FcɛRI‐mediated inhibition of M2PK involved Src kinase, phosphatidylinositol 3‐kinase, PKC and calcium. Direct inhibition of M2PK potentiated FcɛRI‐mediated degranulation and prevention of the FcɛRI‐mediated inhibition of M2PK attenuated mast cell degranulation. Transfection of RBL‐2H3 cells with M1PK which prevents FcɛRI‐induced inhibition of M2PK, markedly reduced their degranulation and exogenous M1PK (i.p.) inhibited ovalbumin‐induced airway hyper‐responsiveness in vivo.

Conclusions and implications:

We have identified a new control point and a novel biochemical pathway in the process of mast cell degranulation. Our study suggests that the FcɛRI‐mediated inhibition of M2PK is a crucial step in responses to allergens. Moreover, the manipulation of glycolytic processes and intermediates could provide novel strategies for the treatment of allergic diseases.

British Journal of Pharmacology (2008) 154, 1035–1046; doi:10.1038/bjp.2008.148; published online 21 April 2008
A cholecystokinin‐1 receptor agonist (CCK‐8) mediates increased permeability of brain barriers to leptin
Authors: Cano V , Merino B , Ezquerra L , Somoza B , Ruiz‐Gayo M
Published: June 2008

Background and purpose:

Leptin regulates energy expenditure and body weight by acting both on the hypothalamus and on peripheral targets. Central actions of leptin are enhanced by cholecystokinin (CCK). The interaction between leptin and CCK makes physiological sense, as rats lacking CCK1 receptors are resistant to peripheral leptin but not to leptin directly infused into the brain. We have recently reported that CCK enhances leptin effects by increasing the entry of leptin into the CNS. The aim of this work was to further characterize the effect of CCK (10 μg kg−1) on leptin kinetics as well as the CCK receptor subtype involved in the interaction between CCK and leptin.

Experimental approach:

Experiments were carried out both in free‐feeding and in fasted rats receiving a single dose of leptin (100 μg kg−1; i.p.). Parameters analysed over the next 6 h were plasma and cerebrospinal fluid concentrations of leptin.

Key results:

We observed that CCK‐8 depressed the increase in plasma leptin that followed the i.p. injection and simultaneously increased leptin concentration in the cerebrospinal fluid from 92±25 to 230±24 pg mL−1 (P<0.05). The effect of CCK‐8 was totally prevented by the CCK1 receptor antagonist, SR‐27,897 (0.3 mg kg−1, s.c.), but not by the CCK2 receptor antagonist, L‐365,260 (1 mg kg−1).

Conclusions and implications:

These results show that CCK plays a role in regulating the access of leptin to the brain and suggest that CCK analogues, acting on CCK1 receptors, might be useful drugs in improving leptin actions within the brain.

British Journal of Pharmacology (2008) 154, 1009–1015; doi:10.1038/bjp.2008.149; published online 21 April 2008