bluuebunny/crossref_metadata_2025 huggingface dataset:
Development and evaluation of a forecasting system for fungal disease in turfgrass
Authors: Palmieri Richard , Tredway Lane , Niyogi Dev , Lackmann Gary M.
Published: December 2006

A forecasting system for fungal infection of turfgrass using weather‐based empirical indices (the ‘Fidanza’ and ‘Schumann’ models) was developed and evaluated for its ability to predict the occurrence of brown patch (Rhizoctonia blight) infection episodes at an experimental site in southeastern USA. Disease observations took place at the Turfgrass Field Laboratory in Raleigh, North Carolina between 8 June and 17 August 2003. Three meteorological data sources were used to generate disease risk indices using the empirical models: an on‐site observing station, an observing station at a nearby airport, and the US National Weather Service's operational Eta weather forecast model. Visual observations of brown patch activity were conducted in the field and used to evaluate the accuracy of the disease prediction models. Results indicate that the Fidanza and Schumann models correctly predicted brown patch activity on 48% and 30% of the days on which disease occurred, respectively. A diagnosis of the model performance of these disease indices was undertaken. Results are dependent on occurrence of high temperatures and rainfall and independent of the source of the meteorological information (on‐site, airport and the Eta model); therefore, regional meteorological information can be effectively applied to develop turfgrass disease forecasting systems. Ongoing efforts are directed towards developing new disease indices and modifying existing indices before an operational disease forecasting system can be implemented. Copyright © 2006 John Wiley & Sons, Ltd.
VELOCITY AND THE VARIABILITY OF MONEY GROWTH: EVIDENCE FROM A VARMA, GARCH-M MODEL
Authors: SERLETIS APOSTOLOS , SHAHMORADI AKBAR
Published: December 2006

This paper uses recent advances in financial econometrics to test the Friedman hypothesis that money supply volatility Granger-causes velocity. Comparisons are made among simple-sum and Divisia velocity series at the M1 and M2 levels of monetary aggregation, using quarterly data from 1959:1 to 2004:3. The conclusion is that the Friedman hypothesis cannot be rejected if money supply volatility is modeled explicitly, using models that capture important volatility effects that previous work has ignored.
S. JAMES PRESS AND BAYESIAN ANALYSIS
Authors: ZELLNER ARNOLD
Published: December 2006

S. James Press's many contributions to statistical research, lecturing, mentoring students, the statistics profession, etc., are summarized. Then some new developments in Bayesian analysis are described and remarks on the future of Bayesian analysis are presented.
BUSINESS-CYCLE FILTERING OF MACROECONOMIC DATA VIA A LATENT BUSINESS-CYCLE INDEX
Authors: DUEKER MICHAEL , NELSON CHARLES R.
Published: December 2006

We use Markov chain Monte Carlo methods to augment, via a novel multimove sampling scheme, a vector autoregressive (VAR) system with a latent business-cycle index that is negative during recessions and positive during expansions. We then sample counterfactual values of the macroeconomic variables in the case where the latent business-cycle index is held constant. These counterfactual values represent posterior beliefs about how the economy would have evolved absent business-cycle fluctuations. One advantage is that a VAR framework provides model-consistent counterfactual values in the same way that VARs provide model-consistent forecasts, so data series are not filtered in isolation from each other. We apply these methods to estimate the business-cycle components of industrial production, consumer price inflation, the federal funds rate, and the spread between long-term and short-term interest rates. These decompositions provide an explicitly counterfactual approach to isolating the effects of the business cycle and to deriving empirical business-cycle facts.
Post-lactational mammary gland regression: molecular basis and implications for breast cancer
Authors: Watson Christine J.
Published: December 2006

During pregnancy, there is a massive increase in the number of luminal epithelial cells in the breast, which are destined to become the milk factories after birth. These cells are no longer required when the young are weaned, and are removed in a carefully orchestrated event called involution. In this process, the secretory epithelial cells die and are replaced by adipocytes, which redifferentiate as the epithelium is removed. It is essential that the gland is properly remodelled to a pre-pregnant state so that successful lactation can occur following a subsequent pregnancy. Furthermore, failure to remove unnecessary lactational alveoli during weaning could result in inflammation and tissue damage. Recently, it has been shown that components in the fatty stroma in involuting breast can promote metastasis. Thus, it is important to understand the molecular mechanisms that regulate involution, how these can fail, the consequences of the remodelling process, and how this knowledge can inform us about breast cancer. In this review, I discuss the roles of the JAK–STAT, NF-κB and other signalling pathways in the regulation of apoptosis and tissue remodelling during involution.
Zufallsbefund: Eosinophilie
Authors: Stöckli  , Geeser
Published: December 2006

Die Eosinophilie, definiert als > 700 eosinophilen Granulozyten pro µl, ist durch die Automatisierung und regelmässige Durchführung der Blutbilduntersuchung ein häufiger Zufallsbefund. Die häufigsten Ursachen weltweit sind Parasitosen, in der westlichen Welt allergische Krankheiten. Meist lässt sich bereits durch eine sorgfältige Anamnese und wenige gezielte Untersuchungen die Ursache finden und so weitere unnötige Abklärungen verhindern. Das Schwergewicht in der Anamnese sollte auf Atopien, Medikamenteneinnahme und mögliche parasitäre Infektionen liegen. Bei Persistenz einer Eosinophilie von mehr als 1.5×109 Zellen/L über sechs Monate muss ein Hypereosinophiles Syndrom in Betracht gezogen werden.
Terrestrial gamma ray flashes observed aboard the Compton Gamma Ray Observatory/Burst and Transient Source Experiment and ELF/VLF radio atmospherics
Authors: Cohen M. B. , Inan U. S. , Fishman G.
Published: December 2006

During its 9‐year lifetime in orbit, the Burst and Transient Source Experiment (BATSE) detector, aboard the Compton Gamma Ray Observatory (CGRO) spacecraft, observed a total of 76 terrestrial gamma ray flashes (TGFs). Of these, simultaneous broadband ELF/VLF data from Palmer Station, Antarctica, were found to be available for six new TGF cases in addition to two previously reported cases (Inan et al., 1996). Analysis of temporal and directional association between radio atmospherics and TGFs reveals solid evidence of an associated radio atmospheric in three of the six events. In one of the three cases with associated radio atmospherics, three consecutive TGFs are apparently linked to three consecutive radio atmospherics. A fourth case exhibits possible evidence of geomagnetically conjugate source lightning. Statistical analyses indicate that when TGFs occur in association with a lightning discharge, they occur ∼1–3 ms after the causative lightning event.
Linearization of a radiative transfer model in spherical geometry
Authors: Walter H. H. , Landgraf J. , Spada F. , Doicu A.
Published: December 2006

For the interpretation of satellite limb observations we investigate the linearization capability of spherical radiative transfer in the ultraviolet and visible part of the solar spectrum, where multiple scattering of light complicates the model simulations. From plane‐parallel radiative transfer it is known that the forward‐adjoint perturbation theory provides a powerful linearization tool. Its application to limb measurement simulations is the subject of this paper. First, we solve the scalar radiative transfer problem in spherical geometry in its forward and adjoint formulation. Subsequently, we apply the perturbation theory approach in the calculation of the derivatives of the intensity at the top of the atmosphere with respect to the absorption properties of a trace gas species in the case of a limb‐viewing satellite instrument. The calculated derivatives are validated with a reference method, and the agreement in the upper atmosphere is very good, whereas deviations occur below the tangent height. Here the determination of the derivatives is clearly sensitive to the discretization of the problem. Finally, we perform an analysis for different viewing scenarios to characterize the capability of the described linearization approach.
Sparse representation of plane wave response matrices for convex targets using local solution modes with band‐limited excitations
Authors: Adams R. J. , Wang G. , Canning F. X. , Davis B. A.
Published: December 2006

A procedure is outlined for determining compressed representations of the plane wave response matrix (P matrix) for transverse magnetic scattering with respect to thezaxis from convex cylinders. The method is based on the determination of band‐limited spectral modes that excite spatially localized solutions to the wave equation and satisfy global boundary conditions. Numerical examples indicate that the proposed method provides a representation of the P matrix with reduced computational complexity.
Mesoscale ionospheric anomalies not associated with space weather
Authors: Rieger M. , Leitinger R. , Bauer S. J.
Published: December 2006

Using the Austrian network of 10 two‐frequency GPS geodetic reference stations, whose location is known with high precision, a study of mesoscale anomalies in the ionosphere over central Europe has been made (and is still in progress for the following years). From the large number of individual observations during the period from 2000 to 2004, maps of small‐scale ionospheric behavior (with a pixel size of 0.5° in latitude and longitude) have been constructed from which local anomalies (at an equivalent height of 250 km) in terms of departure from the model total electron content (TEC) can be recognized. Not all magnetic storms which were most common during the 2000–2002 period of solar maximum showed local effects in the regional ionosphere, but mesoscale ionospheric anomalies which are not (necessarily) associated with space weather were also observed up to 20% of the days of observation, with their highest frequency of occurrence during the winter months (November–February). These anomalies have a typical duration of several hours and seem to be associated with traveling ionospheric disturbances (TIDs) whose origin could lie in gravity waves initiated in the lower atmosphere. Thus TIDs not associated with space weather may play a role in the regional ionosphere but can be detected only by virtue of the dense spatial coverage obtained by a network of GPS stations for precise positioning. From 2000 to 2004, the solar activity and the background ionization decreased considerably. Since TIDs depend on both the properties of atmospheric gravity waves and on the level of ionization, we observed smaller absolute TID amplitudes in 2003–2004 compared with 2000–2001. There is indication that the relative amplitudes have increased slightly, which is consistent with the influence of ion drag on thermosphere dynamics.
Penetration through a slot in a conducting plane backed by a conducting‐walled channel: Transverse magnetic case
Authors: Lockard M. D. , Butler C. M.
Published: December 2006

The penetration of fields through an infinite slot in a conducting plane backed by a channel is examined. The total field in the interior of the channel and above the conducting plane is determined by two independent integral equation methods: (1) coupled integral equations which can be used to determine the fields for a channel with an arbitrarily shaped cross section and (2) a single integral equation which involves a Green's function specific to the shape of the channel. Data from the two methods are presented for the equivalent currents obtained from the integral equations, for the fields near the channel‐backed slot, and for the actual currents present on the conducting surfaces. Methods for determining the currents and fields for the case of a transverse‐electric‐to‐slot‐axis excitation were presented in part 1. This second part focuses on the development of techniques for determining fields and currents in cases where the excitation produces a field that is transverse magnetic to the slot axis.
Thermochronology, geochronology, and upper crustal structure of the Cordillera Real: Implications for Cenozoic exhumation of the central Andean plateau
Authors: Gillis Robert J. , Horton Brian K. , Grove Marty
Published: December 2006

Structural mapping,40Ar/39Ar and fission track thermochronology, U‐Pb geochronology, and basin analysis reveal rapid cooling during middle Eocene–late Oligocene and late Miocene–Pliocene exhumation in the central Andean plateau of Bolivia. In the 4–6 km high Cordillera Real, numerous granites and SW directed fold‐thrust structures define the central Andean backthrust belt along the Altiplano–Eastern Cordillera boundary. U‐Pb zircon analyses indicate Permo‐Triassic granitic magmatism, with less extensive magmatism of late Oligocene age. Mapping reveals low magnitudes of slip (<2–5 km) for most faults on the basis of unit thicknesses, stratigraphic separation, and cutoff relationships. These results suggest that a deeper structure was probably involved in exhumation of rocks from >5 km depth. The ∼26 Ma Quimsa Cruz granite postdated most thrust structures, suggesting that upper crustal shortening in the Cordillera Real had largely ceased by late Oligocene time. Results of40Ar/39Ar and fission track modeling help constrain the moderate to low‐temperature (<350°C) cooling history, revealing two phases of rapid cooling from 45–40 Ma to 26 Ma and from ∼11 Ma onward. Initial cooling coincided with middle Eocene–late Oligocene deformation in the backthrust belt and associated deposition of coarse clastic sediments in the Altiplano basin. Eocene‐Oligocene exhumation of ∼7.5 km of upper crust is estimated on the basis of thermochronologic data. Rapid late Miocene and younger cooling involved an estimated ∼3.5 km of exhumation and occurred in the apparent absence of upper crustal shortening. These findings suggest that crustal shortening and resultant exhumation of middle Eocene–late Oligocene age played a major role in construction of the central Andes. However, for late Miocene exhumation, the importance of alternative, nonshortening mechanisms is difficult to ascertain due to a poor understanding of subsurface structures. We speculate that greater precipitation on the eastern edge of the central Andean plateau north of ∼17.5°S was a key factor in driving rapid, youthful exhumation of the Cordillera Real.
Coastal Louisiana in crisis: Subsidence or sea level rise?
Authors: González Juan L. , Tornqvist Torbjörn E.
Published: December 2006

The drowning of wetlands and barrier islands in coastal Louisiana has become a widely publicized environmental catastrophe in the wake of hurricanes Katrina and Rita in 2005. The devastation caused by these storms has reenergized the debate about restoring the natural coastal‐defense system and building higher and sturdier levees, in anticipation of future storms. Understanding the contributions of land subsidence and eustatic (global) sea level rise to Louisiana's wetland loss is crucial to the success of any plan designed to protect coastal communities. It is argued here that accelerated sea level rise in the future may pose a larger threat than subsidence for considerable portions of coastal Louisiana.
Source estimates of the May 2006 Java earthquake
Authors: Nakano Masaru , Kumagai Hiroyuki , Miyakawa Koji , Yamashina Tadashi , Inoue Hiroshi , Ishida Mizuho , Aoi Shin , Morikawa Nobuyuki , Harjadi Prih
Published: December 2006

In the early morning of 27 May 2006, local time, central Java was jolted by strong seismic ground motion. In spite of the moderate size of the earthquake (Mw = 6.4), it caused severe damage nearYogyakarta city. According to a report from the Social Affairs Ministry of Indonesia, more than 5700 people were killed, 38,000 injured, and 423,000 evacuated.

As a result of the shaking, more than 126,000 buildings collapsed, and more than 392,000—including those of the famous Prambanan temple complex, located about 17 kilometers east of Yogyakarta—were severely damaged (Figure 1).
Canada extends Radarsat‐1 mission
Authors: Zielinski Sarah
Published: December 2006

The Canadian Space Agency will continue funding the Earth‐observing satellite Radarsat‐1 through at least the end of the International Polar Year (IPY) in March 2009, Eos has learned. Rolf Mamen, director general of Space Operations at the Canadian Space Agency (CSA) said that the agency was able to find funds to continue support for Radarsat‐1 for the next two years—a cost of less than CAN$10 million per year—and that the Treasury Board of Canada Secretariat approved the program in October. Mamen noted that Radarsat‐1 “has been working well. It is more than meeting specifications,” despite some earlier predictions that the satellite might run out of fuel or otherwise fail.
Recent progress in Aeolian research
Authors: Lancaster Nicholas , Gillies John A. , Nickling William G.
Published: December 2006

Aeolian processes‐involving erosion, transportation, and deposition of sediment by wind‐occur in a variety of environments including coastal areas, semiarid and arid regions, and agricultural fields. Aeolian processes also occur on some planetary bodies, notably Mars and possibly Venus and on Saturn's moon Titan. Aeolian processes are responsible for the emission and/or mobilization of dust and the formation of areas of sand dunes. Fluctuations in the intensity and geographical extent of wind transport of sediments during the Quaternary have produced an important paleoclimatic record in loess deposits and areas of vegetationstabilized sand dunes.
The unknown and the uncertain in Earth system modeling
Authors: Le Quéré Corinne
Published: December 2006

With the planet heating up, the urgent need to reduce uncertainty in climate projections could have consequences in the way Earth system models evolve. I argue that a period of confusion in the development of models can be beneficial and can lead to improved understanding and reduced uncertainty in due time. I have identified three phases of development in modeling—the illusion, the chaos, and the relief—through which models seem to evolve before their results can be said to approach the truth with some confidence.

Whereas these phases are based only on my limited observation of the field, they underline the fact that answers to scientific questions are usually ‘unknown’ before they become ‘uncertain.’ Realizing in which phase a model component may be could facilitate their development. I give examples from carbon cycle modeling and highlight the benefits of encouraging new and audacious approaches in modeling.
More than science at risk as U.S. icebreakers age
Authors: Zielinski Sarah
Published: December 2006

With only two operational icebreakers, and one of those near the end of its lifespan, the U.S. National Science Foundation has developed contingency plans to ensure access to the polar regions for science. However, the U.S. government may need to acquire new icebreakers if the nation requires access for other purposes in addition to science, such as commerce and national security, according to a recent report from a committee of the U.S. National Research Council (NRC).

Hajo Eicken, from the Geophysical Institute of the University of Alaska Fairbanks and a member of the NRC committee, said that as polar ice conditions and temperatures become more “benign,” “industry, law enforcement, and various other activities are actually going to move into these areas.” However, he said that because of the nature of geography and ice circulation, there will be “more critical situations that require support by heavy polar‐class icebreakers.”
Cold‐water coral mounds revealed
Authors: William Trevor , Kano Akihiro , Ferdelman Timothy , Henriet Jean‐Pierre , Abe Kohei , Andres Miriam S. , Bjerager Morten , Browning Emily L. , Cragg Barry A. , De Mol Ben , Dorschel Boris , Foubert Anneleen , Frank Tracy D. , Fuwa Yuji , Gaillot Philippe , Gharib Jamshid J. , Gregg Jay M. , Huvenne Veerle Ann Ida , Léonide Philippe , Li Xianghui , Mangelsdorf Kai , Tanaka Akiko , Monteys Xavier , Novosel Ivana , Sakai Saburo , Samarkin Vladimir A. , Sasaki Keiichi , Spivack Arthur J. , Takashima Chizuru , Titschak Jürgen
Published: December 2006

The discovery of mounds and reefs hosting cold‐water coral ecosystems along the northeastern Atlantic continental margins has propelled a vigorous effort over the past decade to study the distribution of the mounds, surface sediments, the ecosystems they host, and their environments [Hovland et al., 1994; Freiwald and Roberts, 2005].This effort has involved swath bathymetry, remotely operated vehicle deployments, shallow coring, and seismic surveys.

Global coverage is difficult to gauge, but studies indicate that cold‐water corals may cover as large an area as the better known warm‐water corals that form shallow reefs (284,300 square kilometers) [Freiwald et al., 2005]. Cold‐water corals occur in a variety of forms and settings, from small isolated colonies or patch reefs to giant mound structures such as those found west of Ireland.
Volcanic island appears near Tonga
Authors: Zielinski Sarah
Published: December 2006

A volcano known as Home Reef is now believed to be the source of a small island that appeared recently in Tonga, according to scientists from the Smithsonian Institution's Global Volcanism Program who had initially placed the location of the eruption and resulting island at nearby Metis Shoal.

Mariners onboard the yacht Maiken reported strong eruptions in the area of Home Reef on 12 August and the appearance of an island the following day The Ozone Monitoring Instrument onboard the NASA satellite Aura detected sulfur dioxide emissions in the same region on 8–15 August. In addition, people in Fiji and on ships traveling through the region reported seeing large amounts of floating pumice into September.
Twin satellites to study Sun
Authors: Kumar Mohi
Published: December 2006

Twin satellites of the Solar Terrestrial Relations Observatory (STEREO) mission, launched by NASA on 25 October, promise to provide scientists with three‐dimensional views of the Sun and solar wind. The satellites also will help with exploring the origin, evolution, and effects of coronal mass ejections (CMEs).CMEs can hurtle billions of tons of solar plasma into interplanetary space, which can disrupt satellite systems, radio communications, and power grids. CMEs also can pose hazards to space‐faring astronauts. STEREO'S satellites will monitor CMEs in three dimensions, with one spacecraft flying behind the Earth at a slightly wider orbit and another flying ahead at a slightly narrower orbit, allowing for depth perception. Instrument packages mounted on each satellite also will observe properties of solar particles and track radio disturbances that move from the Sun to the Earth. Data will be used to help predict adverse space weather events.
Mission Moho: Formation and evolution of oceanic lithosphere
Authors: Christie David M. , Ildefonse Benoit , Abe Natsue , Arai Shoji , Bach Wolfgang , Blackman Donna K. , Duncan Robert , Hooft Emelie , Humphris Susan E. , Miller D. Jay
Published: December 2006

The formation and evolution of the oceanic lithosphere is the dominant process in the chemical differentiation and physical evolution of our planet. Plate tectonic processes completely repave the ocean basins every 100–200 million years. Lithosphere formation encompasses the transfer and transformation of material and energy from Earth's mantle to the crust and from the crust to the ocean and atmosphere. Independent of sunlight, the evolving ocean crust supports life in unique seafloor and subseafloor habitats that may resemble Earth's earliest ecosystems. From its formation until its return to the mantle by subduction, the evolving oceanic lithosphere interacts with seawater, sequesters water and other materials, and ultimately recycles them back into the mantle.
A future climate scenario of regional changes in extreme climate events over China using the PRECIS climate model
Authors: Zhang Yong , Xu Yinlong , Dong Wenjie , Cao Lijuan , Sparrow Michael
Published: December 2006

Based on the PRECIS climate model system, we simulate the distribution of the present (1961∼1990) and future (2071∼2100) extreme climate events in China under the IPCC SRES B2 scenario. The results show that for the present case PRECIS simulates well the spatial distribution of extreme climate events when compared with observations. In the future the occurrence of hot events is projected to be more frequent and the growing season will lengthen, while the occurrence of cold events is likely to be much rarer. A warming environment will also give rise to changes in extreme precipitation events. There would be an overall increasing trend in extreme precipitation events over most of China. The southeast coastal zone, the middle and lower reaches of the Yangtze River and North China are projected to experience more extreme precipitation than the present.
Structure and origin of the subtropical South Indian Ocean Countercurrent
Authors: Siedler Gerold , Rouault Mathieu , Lutjeharms Johann R. E.
Published: December 2006

The structure of the subtropical South Indian Ocean Countercurrent (SICC) is revealed by altimeter‐derived absolute geostrophic surface velocities. It is a narrow, eastward‐flowing current between 22° and 26°S confined to planetary wave trains which propagate westward through the Indian Ocean. Multi‐year averaging identifies it as a well‐defined current between Madagascar and 80°E, continuing with lower intensity between 90° and 100°E. It virtually coincides with the northern limit of Subtropical Underwater subduction. Geostrophic currents from hydrographic sections closely correspond to these surface patterns. Volume transports of the countercurrent down to 800 dbar are of order (107 m3 s−1). Evidence is provided for a narrow branch of the South Equatorial Current (SEC) approaching Madagascar near 18°S and feeding the southern East Madagascar Current (EMC) which appears to continue westward around the southern tip of Madagascar. It then partially retroflects and nourishes the SICC.
Atmospheric pressure change associated with the 2003 Tokachi‐Oki earthquake
Authors: Watada Shingo , Kunugi Takashi , Hirata Kenji , Sugioka Hiroko , Nishida Kiwamu , Sekiguchi Shoji , Oikawa Jun , Tsuji Yoshinobu , Kanamori Hiroo
Published: December 2006

Clear atmospheric pressure changes associated with the 2003 Tokachi‐Oki, Japan, earthquake with Mw 8.3 were recorded with the microbarographs distributed in Japan. The pressure change starts at the arrival of seismic waves and reaches its maximum amplitude at the arrival of Rayleigh waves, suggesting that the observed pressure change was driven by the ground motion of seismic waves passing by the site. We computed the seismic‐to‐pressure transfer function (i.e., the spectral ratio of the pressure change to the vertical ground motion velocity) for periods between 10 to 50 s from the co‐located barograph and seismograph records. Comparison of the observed transfer function with the theoretical one including the finite frequency and wavelength effects for a gravitationally stratified isothermal atmosphere confirms that the observed amplitude and phase of the pressure change are explained by the acoustic coupling between the atmosphere and the ground just beneath the sensors.
Lateral entrapment of sediment in tidal estuaries: An idealized model study
Authors: Huijts K. M. H. , Schuttelaars H. M. , de Swart H. E. , Valle‐Levinson A.
Published: December 2006

Two physical mechanisms leading to lateral accumulation of sediment in tidally dominated estuaries are investigated, involving Coriolis forcing and lateral density gradients. An idealized model is used that consists of the three‐dimensional shallow water equations and sediment mass balance. Conditions are assumed to be uniform in the along‐estuary direction. A semidiurnal tidal discharge and tidally averaged density gradients are prescribed. The erosional sediment flux at the bed depends both on the bed shear stress and on the amount of sediment available in mud reaches for resuspension. The distribution of mud reaches over the bed is selected such that sediment transport is in morphodynamic equilibrium, that is, tidally averaged erosion and deposition of sediment at the bed balance. Analytical solutions are obtained by using perturbation analysis. Results suggest that in most estuaries lateral density gradients induce more sediment transport than Coriolis forcing. When frictional forces are small (Ekman number E < 0.02), the Coriolis mechanism dominates and accumulates sediment on the right bank (looking up‐estuary in the Northern Hemisphere). On the other hand, when frictional forces are moderate to high (E > 0.02), the lateral density gradient mechanism dominates and entraps sediment in areas with fresher water. Results also show that the lateral sediment transport induced by the semidiurnal tidal flow is significant when frictional forces are small (E ∼ 0.02). Model predictions are in good agreement with observations from the James River estuary.
Global modeling of biogenic bromocarbons
Authors: Warwick N. J. , Pyle J. A. , Carver G. D. , Yang X. , Savage N. H. , O'Connor F. M. , Cox R. A.
Published: December 2006

A global three‐dimensional chemical transport model has been used to simulate atmospheric bromoform using a variety of prescribed surface emission scenarios and a simple atmospheric chemistry scheme. Model simulations indicate that global emissions of bromoform calculated previously using top‐down methods are too low, and emissions are likely to be significantly larger than suggested in the World Meteorological Organization's reports on the Scientific Assessment of Ozone Depletion of 1998 and 2002. Our simulations suggest that global emissions of bromoform are in the range of 400–600 GgCHBr3/yr and that a large proportion of emissions are situated in tropical regions. Both these factors are likely to have an important influence on estimates of the quantity of bromine transported from the surface to the lower stratosphere by short‐lived bromocarbon species and its subsequent impact on ozone in this region. Further simulations including methyl bromide, bromoform and the other major short‐lived bromocarbons emitted from the ocean (CH2Br2, CH2BrCl, CHBr2Cl, CHBrCl2) provide estimates on the amount of reactive bromine in the troposphere and lower stratosphere derived from these compounds.
Lidar temperature measurements of gravity waves over Kühlungsborn (54°N) from 1 to 105 km: A winter‐summer comparison
Authors: Rauthe M. , Gerding M. , Höffner J. , Lübken F.‐J.
Published: December 2006

Since August 2002, temperature measurements from 1 to 105 km are performed at the Leibniz Institute of Atmospheric Physics in Kühlungsborn (54°N) with a combination of different lidars. Results from 14 nights in winter and 31 in summer are presented. Nightly mean profiles and fluctuations with a temporal and vertical resolution of 15 min and 1 km, respectively, are derived. In both seasons, wave energy propagates upward (phase propagates downward) with vertical phase speeds of −0.25 to −1.9 m/s. Phase speeds are generally larger in the mesosphere compared to the stratosphere because of decreasing static stability. Wave periods are found in the entire range of 1–8 hours (given by experimental constraints) with no preference for particular periods. The observed vertical wavelengths cover the entire instrumental range of 5–50 km, but the majority lies below 22 km in both seasons. In single nights, a few waves (up to three) dominate the wave spectrum and represent 45–65% of the entire variability. Wave amplitudes generally increase with altitude with a scale height of ∼18–22 km, i.e., less than expected (14 km) for propagation conserving momentum flux density. The gravity wave energy loss changes with altitude and is different in both seasons. Local fluctuation minima (“nodes”) are often observed, frequently colocated with convective instabilities. Temperature fluctuations are generally smaller in summer compared to winter (maximum values are 10 and 25 K, respectively). Applying gravity wave polarization relations to the mean winter and summer lidar temperature profiles, the difference of fluctuations is basically determined by the background conditions, especially at ∼60–80 km.
Shoreline response to autogenic processes of sediment storage and release in the fluvial system
Authors: Kim Wonsuck , Paola Chris , Swenson John B. , Voller Vaughan R.
Published: December 2006

Experimentally determined shoreline migration rates show high‐frequency autogenic variability superimposed on low‐frequency allogenic shoreline responses induced by eustatic base level change. This variability persists even when the shoreline migration is averaged laterally, indicating time variation in total sediment discharge reaching the shoreline. The magnitude of autogenic variability in shoreline migration rate changes by roughly a factor of 3 depending on the shoreline migration direction: It is strongest during transgression, when the shoreline is on average migrating against the mean sediment flow, and weakest during regression, when the shoreline is migrating with the mean sediment flow. We propose that this time variation is due to overall sediment storage and release in the fluvial system. We use a one‐dimensional geometric model to model the autogenic signals observed in the experiment. The model uses small periodic changes in the fluvial slope to represent the effects of storage and release of supplied sediment due to intrinsic variation in the transport efficiency of the fluvial system. The periodic pulses of sediment discharge to the shoreline required in the model to explain the variations in shoreline migration can exceed by an order of magnitude the mean allogenic sediment discharge. The slope variability required in the model to explain the autogenic shoreline signals is 1–4% of the mean slope. This is well within the range of observed variability in depositional fluvial slopes. We propose that at least part of this observed variability is real; that is, the long‐profile slope of a depositional river system may have an intrinsic “elasticity” of a few percent of its mean value, even under steady forcing. Autogenic slope variation of this magnitude could readily produce parasequence‐scale deposits in the stratigraphic record.
Dual elliptically tapered antipodal slot antenna loaded by curved terminations for ultrawideband applications
Authors: Qing Xianming , Chen Zhi Ning , Chia Michael Yan Wah
Published: December 2006

The dual elliptically tapered antipodal slot antenna (DETASA) is a modified version of the antipodal Vivaldi antenna. The DETASA is formed by elliptical tapering of the inner and outer edges of the slotline conductors of the antipodal Vivaldi radiator. To enhance the performance of the DETASA, this paper presents a modified configuration by using curved conducting terminations at the end of the slotline conductors. The proposed DETASA has the advantages of extended lower operating frequency, flatter gain response, symmetrical radiation patterns, and improved impedance matching across the operating band over the conventional DETASA. As an example, a prototype covering the ultrawideband (UWB) frequency range (3.1–10.6 GHz) is designed and characterized in terms of impedance matching, gain, radiation pattern, transfer function, and group delay in the frequency domain, as well as impulse response and fidelity in the time domain. The prototype which is made on a 0.8128 mm Rogers RO4003 substrate with the dimensions of 80 × 80 mm shows good impedance and radiation performance over 3–20 GHz: Return loss is less than –10 dB; gain variation is less than 4 dB (4–8 dBi); and symmetrical radiation patterns and constant group delay have also been achieved. In the time domain, the prototype features good impulse response and high fidelity (F is more than 0.9) as well. The simulated and measured results show that the proposed DETASA is capable of providing enhanced impedance and radiation performance suitable, in particular, for UWB applications.
A monthly interception equation based on the statistical characteristics of daily rainfall
Authors: de Groen Marieke M. , Savenije Hubert H. G.
Published: December 2006

This paper presents a simple analytical equation for monthly interception on the basis of the combination of a daily threshold model with the probability distribution of daily rainfall. In this paper, interception has a wider definition than merely canopy interception. It is the part of the rainfall that evaporates after it has been stored on the wetted surface, which includes the canopy, the understory, the bottom vegetation, the litter layer, the soil, and the hard surface. Interception is defined as the process of evaporation from intercepted rainfall. It is shown that this process has a typical timescale of 1 day. Monthly interception models can be improved by taking the statistical characteristics of daily rainfall into account. These characteristics appear to be less variable in space than the rainfall itself. With the statistical characteristics of daily rainfall obtained at a few locations where reliable records are available (for example, airports) monthly models can be improved and applied to larger areas (20–200 km). The equation can be regionalized, making use of the Markov property of daily rainfall. The equation obtained for monthly interception is similar to Budyko's curve.
Arterial versus Total Blood Volume Changes during Neural Activity-Induced Cerebral Blood Flow Change: Implication for BOLD fMRI
Authors: Kim Tae , Hendrich Kristy S , Masamoto Kazuto , Kim Seong-Gi
Published: December 2006

Quantifying both arterial cerebral blood volume ( CBVa) changes and total cerebral blood volume ( CBVt) changes during neural activation can provide critical information about vascular control mechanisms, and help to identify the origins of neurovascular responses in conventional blood oxygenation level dependent (BOLD) magnetic resonance imaging (MRI). Cerebral blood flow ( CBF), CBVa, and CBVt were quantified by MRI at 9.4T in isoflurane-anesthetized rats during 15-s duration forepaw stimulation. Cerebral blood flow and CBVa were simultaneously determined by modulation of tissue and vessel signals using arterial spin labeling, while CBVt was measured with a susceptibility-based contrast agent. Baseline versus stimulation values in a region centered over the somatosensory cortex were: CBF = 150 ± 18 versus 182 ± 20 mL/100 g/min, CBVa = 0.83 ± 0.21 versus 1.17 ± 0.30 mL/100 g, CBVt = 3.10 ± 0.55 versus 3.41 ± 0.61 mL/100 g, and CBVa/ CBVt = 0.27 ± 0.05 versus 0.34 ± 0.06 ( n = 7, mean ± s.d.). Neural activity-induced absolute changes in CBVa and CBVt are statistically equivalent and independent of the spatial extent of regional analysis. Under our conditions, increased CBVt during neural activation originates mainly from arterial rather than venous blood volume changes, and therefore a critical implication is that venous blood volume changes may be negligible in BOLD fMRI.
Stochastic resonance in superconducting loops containing Josephson junctions. Numerical simulation
Authors: Glukhov A. M. , Turutanov O. G. , Shnyrkov V. I. , Omelyanchouk A. N.
Published: December 2006

A numerical simulation of the stochastic resonance is carried out in the adiabatic approximation in overdamped systems based on superconducting loops closed by a weak link. The systems under consideration include a single-ring rf SQUID, two rings coupled by a common magnetic flux, and a ring closed by a 4-terminal Josephson junction. It is shown that coupling of single SQUID rings enhances the gain and the signal-to-noise ratio. These effects can be used to create new stochastic SQUID antennas for measurements of harmonic and quasi-harmonic signals. The stochastic resonance in 4-terminal SQUIDS exists even at values of the dimensionless inductance l<1.
Evolution of the pseudogap state in weakly praseodymium-doped Y1−zPrzBa2Cu3O7−δ single crystals with a specified topology of planar defects
Authors: Obolenskiĭ M. A. , Vovk R. V. , Bondarenko A. V.
Published: December 2006

The basal-plane conductance is investigated in Y–Ba–Cu–O and Y1−zPrzBa2Cu3O7−δ single crystals having a system of unidirectional twin boundaries. It is shown that the partial substitution of Y by Pr leads to the formation of two superconducting phases with different critical temperatures. Praseodymium impurities are efficient scattering centers for normal and fluctuation carriers. In the case of weak doping (below z≈0.05) the doping of Y–Ba–Cu–O single crystals with Pr brings about significant narrowing of the temperature interval in which the pseudogap state is realized in the ab plane.
Magnon excitations in vortex-state nanorings
Authors: Zaspel C. E. , Owens J. W. , Ivanov B. A.
Published: December 2006

The magnon mode excitation spectrum is calculated using the linearized Landau–Lifshitz equations applied to the ring in the vortex ground state. A combination of analytical techniques with numerical evaluation of integrals is used to obtain the mode frequency, with the effective magnetostatic volume charge as a small perturbation. In general, the modes can be classified according to radial number n and azimuthal number m. It is shown that the frequency increases as n increases, and the frequency decreases as m increases.
Thermomagnetic phenomena in layered conductors
Authors: Kirichenko O. V. , Peschansky V. G. , Hasan R. A.
Published: December 2006

A theoretical study is made of thermomagnetic phenomena in layered conductors in the presence of several groups of charge carriers. The thermopower at high external magnetic field is found as a function of the strength and orientation of the field; experimental study of this field dependence permits investigation of the structure of the energy spectrum of the charge carriers.
Quantum creep of β–Sn in the normal and superconducting states. Influence of the NS transition on work hardening
Authors: Natsik V. D. , Soldatov V. P. , Ivanchenko L. G. , Kirichenko G. I.
Published: December 2006

Previously we investigated the kinetics of transient logarithmic creep of β–tin single crystals at very low temperatures 0.5K<T<4.2K with the sample under deformation in the normal (N) electronic state. In a continuation of that research, here we determine the boundary temperature Tg≈1.3K separating the regions of thermally activated (T>Tg) and quantum (T<Tg) plasticity governed by the motion of dislocations through Peierls barriers. Experiments are done on samples in the superconducting (S) state (0.5K<T<Tc=3.7K). It is shown that the NS transition preserves the logarithmic type of creep, its quantum character in the region T<Tg, and the value of the boundary temperature (TgS≈TgN≈1.3K). Analysis of the curves of the logarithmic creep in the quantum region can yield empirical estimates for the work hardening coefficient κ of the samples. It is found to increase significantly at the NS transition: along the whole deformation curve the work hardening in the S state occurs more intensely, and, on the average, κS≈1.5κN. Such an effect has been observed previously in a study of the plasticity of a series of fcc metals by the method of active deformation at a constant rate (V. V. Pustovalov, I. N. Kuz’menko, N. V. Isaev, V. S. Fomenko, S. É. Shumlin, Fiz. Nizk. Temp. 30, 109 (2004) [Low Temp. Phys. 30, 82 (2004)]). A comparison of the results of this study with previous results suggests that the increase in intensity of the work hardening at the superconducting transition is of a general nature for metallic superconductors and is manifested for other deformation regimes as well. The possible causes of the effect are discussed in the general conceptual framework of dislocation physics.
Perceptual Transparency in 3- to 4-Month-Old Infants
Authors: Otsuka Yumiko , Kanazawa So , Yamaguchi Masami K
Published: December 2006

We examined perceptual transparency in infants. In a previous study, Johnson and Aslin (2000 Developmental Psychology36 808 – 816) found that 4-month-olds could perceive transparency in a moving chromatic display, but not in an achromatic display. In this study, we further examined perceptual transparency in infants using a static achromatic display. Considering the development of figural organisation and contrast sensitivity, we assumed that 3- to 4-month-olds would perceive transparency even in a static achromatic display. We created a transparency and a non-transparent display composed of a partially overlapping circle and square, by switching the colours. Infants aged 3 to 4 months ( n = 24) were familiarised with the transparency display (experiment 1) or with the non-transparent display (experiment 2). Then, they were confronted with a uniform colour and a two-colour figure. Infants showed novelty preference for the two-colour figure after they had been familiarised with the transparency display (experiment 1), but not after they had been familiarised with the non-transparent display (experiment 2). These results suggest that 3- to 4-month-old infants can perceive transparency in a static achromatic display.
A Study of Impaired Judgment of Eye-Gaze Direction and Related Face-Processing Deficits in Autism Spectrum Disorders
Authors: Wallace Simon , Coleman Michael , Pascalis Olivier , Bailey Anthony
Published: December 2006

The purpose of this study was to examine whether individuals with autism spectrum disorders (ASD) use the same cognitive strategies as typically developing individuals when processing eye-gaze direction. Subjects viewed pictures of whole faces, the eye region alone, and pairs of arrows presented for 40, 70, or 100 ms, and responded according to the direction the eyes were looking or the arrows pointing (left, right, or straight ahead). Experiment 1 demonstrated that typically developing adults ( n = 41) were more accurate and showed shorter reaction times when judging direction of averted eye gaze in the context of the whole face than when only the eyes were visible (eye-region-alone condition). Furthermore, in the eye-region-alone condition participants were more accurate and faster at judging direct eye gaze than averted eye gaze. The same task was used in experiment 2 to compare the performance of a group of individuals with ASD ( n = 24) with that of a group of IQ-matched typically developing individuals ( n = 26). The performance of the control participants was identical to that observed in experiment 1. Individuals with ASD were able to judge eye-gaze direction accurately at short exposure duration; however, they failed to show the typical advantage for judging averted gaze in whole faces and the increased sensitivity to direct gaze in the eye-region-alone condition. The findings are discussed in terms of impairments to discrete gaze-processing and face-processing mechanisms, and the connectivity between these mechanisms.
Body Mass Index and Waist: Hip Ratio are Not Enough to Characterise Female Attractiveness
Authors: Pokrywka Leszek , Čabrić Milan , Krakowiak Helena
Published: December 2006

The assessment of characteristic body features of Miss Poland beauty contest finalists compared with the control group, can contribute to recognising the contemporary ideal of beauty promoted by the mass media. The studies of Playboy models and fashion models conducted so far have been limited to the following determinants of attractiveness: body mass index, waist: hip ratio, and waist: chest ratio, which only partially describe the body shape. We compared 20 body features of the finalists of Miss Poland 2004 beauty contest with those of the students of Medical Academy in Bydgoszcz. Discriminant analysis showed that the thigh girth – height index, waist: chest ratio, height, and body mass index had the greatest discrimination power distinguishing the two groups. A model of Miss Poland finalists figure assessment is presented which allows one to distinguish super-attractive women from the control group.