bluuebunny/crossref_metadata_2025 huggingface dataset:
Organisch oder nicht organisch?
Authors: Mumenthaler M.
Published: November 2008

Jedes Beschwerdebild und jeder Funktionsausfall kann psychogen sein. Die Unterscheidung organischer Ausfälle von nicht organischen wird durch das Vorhandensein resp. Fehlen von objektiven pathologischen Befunden, die zu den angegebenen Ausfällen passen, ermöglicht. Fallbeispiele illustrieren psychogene Störungen, aber auch solche, die zu unrecht psychogen wirken, jedoch organisch sind.
Wenn der Stammbaum zählt: ein ungewöhnlicher Fall einer linksseitigen Hemiparese
Authors: Schmidhauser T. , Riglietti A. , Pons M.
Published: November 2008

Wir berichten über eine 35-jährige Frau, welche aufgrund einer akut aufgetretenen linksseitigen Hemiparese in unsere Notfallstation eingewiesen wurde. Die klinische Untersuchung bei Eintritt zeigte die bereits beschriebene linksseitige Hemiparese sowie überall verstreute Teleangiektasien auf der Ober- und Unterlippe, auf der Zunge und auf der Haut. Es erfolgte eine komplette radiologische Abklärung durch ein zerebrales CT sowie MRI, die beide eine rechtsseitige fronto-parietale Läsion zeigten, vereinbar mit einem Abszess. Diese Vermutung wurde dann neurochirurgisch auch bestätigt. Eine sorgfältige Familienanamnese ergab, dass mehrere Familienmitglieder ähnliche klinische Merkmale zeigten oder gezeigt hatten. Somit konnte die Diagnose eines Morbus Rendu-Osler-Weber gestellt werden. Dieser Fall zeigt eindrücklich, wie wichtig eine sorgfältige Erhebung der Anamnese, auch der Familienanamnese, im klinischen Alltag ist.
Mission design of the Phoenix Mars Scout mission
Authors: Guinn Joseph R. , Garcia Mark D. , Talley Kevin
Published: November 2008

The Phoenix Mars Scout Lander, the first robotic explorer in NASA's “Scout Program,” launched on 4 August 2007, will land on the northern plains of Mars in late May 2008, prior to the northern Martian summer. The Phoenix mission “follows the water” by landing in a region where NASA's Mars Odyssey orbiter has discovered evidence of ice‐rich soil very near the Martian surface. For 3 months after arrival, the fixed Lander will perform in situ investigations that will characterize the chemistry of the materials at the local surface, subsurface, and atmosphere, and will identify potential evidence of key elements significant to the biological potential of Mars. The Lander will employ a robotic arm to dig to the ice layer, and will analyze the acquired samples using a suite of deck‐mounted science instruments. The development of the baseline strategy to achieve the objectives of this mission involves the integration of a variety of elements into a coherent mission plan. These elements are involved in defining plans for the launch phase, interplanetary cruise, atmospheric entry, descent and landing, landing site selection, and the surface operations. An overview of the integrated mission plan, from launch through surface operations, is described.
Anthropogenic water vapor emissions in Tokyo
Authors: Moriwaki Ryo , Kanda Manabu , Senoo Hiroshi , Hagishima Aya , Kinouchi Tsuyoshi
Published: November 2008

Temporal and spatial variations in anthropogenic water vapor (AWV) emissions and anthropogenic heat (AH) in Tokyo were estimated using data from a geographic information system (GIS) and an energy‐consumption database. The maximum value of AWV exceeded 500 W m−2 in summer in central Tokyo. Estimations of AWV were validated with field‐measured data. The estimated and measured data agreed well, indicating that anthropogenic sources such as district cooling systems release large amounts of water vapor into the atmosphere.
Crustal deformation in western Sichuan region and implications for 12 May 2008 Ms 8.0 earthquake
Authors: Meng Guo‐jie , Ren Jin‐wei , Wang Min , Gan Wei‐jun , Wang Qi , Qiao Xue‐jun , Yang Yong‐lin
Published: November 2008

We have established 65 GPS stations and derive a detailed horizontal deformation distribution in western Sichuan region, in conjunction with previous measurements at additional 90 stations. The resulting velocity field shows that strike‐slip fault system here plays a significant role in adjusting crustal movements (in direction and magnitude) along the eastern borderland of the Tibetan Plateau. We find Xianshuihe fault is essentially creeping in its southeasternmost portion with left‐lateral slip rate of 8.4 ± 2.8 mm/a. We report ∼5.6 mm/a left‐lateral slip rate across Anninghe and Daliangshan fault. Mabian fault slips left‐laterally at the rate of 2.5 ± 1.4 mm/a with nearly null fault‐normal motion. Deformation across Litang and Yunongxi fault appear insignificant at present time. Our results reveal recently ruptured Longmenshan fault has both right‐lateral slip rate and compressional rate close to 2.0 ± 1.0 mm/a, implying that the Longmenshan fault indeed absorbs some northeastern motion of Tibetan Plateau and likely causes strain accumulation there, which leads to the breakout of the 12 May 2008 Ms 8.0 earthquake. We also find several domains with markedly localized strain rates, which are associated with individual structures.
Flow splitting modifies the helical motion in submarine channels
Authors: Islam M. Ashraful , Imran Jasim , Pirmez Carlos , Cantelli Alessandro
Published: November 2008

Intricately meandering channels of various scales constitute a major morphological feature of the submarine slope and fan systems. These channels act as conduits of density‐driven gravity underflows and in turn are shaped by these underflows. The relationship between channel curvature and the dynamics of sediment‐laden underflows commonly known as turbidity current has been an enigma, and recently, a subject of controversy. This contribution unravels the flow field of turbidity current at submarine channel bends captured from large scale laboratory experiments. The experimental results show that a mildly sloping channel bank greatly enhances the tilt of the turbidity current‐ambient water interface, so much so that the current completely separates from the convex or the inside bank. We also show that irrespective of the shape of the channel cross section, two cells of helical flow appear in confined submarine bend flow. The near‐bed cell has a circulation pattern similar to that observed in fluvial channels; the other cell has an opposite sense of rotation. If, on the other hand, a portion of the flow detaches from the body of the current and spills to the concave or outside overbank area, the upper circulation cell becomes suppressed by the resulting lateral convection.
Broadband simulations for Mw7.8 southern San Andreas earthquakes: Ground motion sensitivity to rupture speed
Authors: Graves Robert W. , Aagaard Brad T. , Hudnut Kenneth W. , Star Lisa M. , Stewart Jonathan P. , Jordan Thomas H.
Published: November 2008

Using the high‐performance computing resources of the Southern California Earthquake Center, we simulate broadband (0–10 Hz) ground motions for three Mw7.8 rupture scenarios of the southern San Andreas fault. The scenarios incorporate a kinematic rupture description with the average rupture speed along the large slip portions of the fault set at 0.96, 0.89, and 0.84 times the local shear wave velocity. Consistent with previous simulations, a southern hypocenter efficiently channels energy into the Los Angeles region along the string of basins south of the San Gabriel Mountains. However, we find the basin ground motion levels are quite sensitive to the prescribed rupture speed, with peak ground velocities at some sites varying by over a factor of two for variations in average rupture speed of about 15%. These results have important implications for estimating seismic hazards in Southern California and emphasize the need for improved understanding of earthquake rupture processes.
A long‐term climatology of North Atlantic polar lows
Authors: Zahn Matthias , von Storch Hans
Published: November 2008

A dynamical downscaling of the 6‐hourly 1948–2006 NCEP/NCAR re‐analyses for the subarctic region of the North Atlantic has been used to derive a climatology of polar lows by means of a tracking algorithm based on the simulated bandpass filtered MSLP‐fields. This climatology is consistent with the limited observational evidence in terms of frequency and spatial distribution. The climatology exhibits strong year‐to‐year variability but weak decadal variability and a negligible trend. A Canonical Correlation Analysis describes the conditioning of the formation of polar lows by characteristic meridional seasonal mean flow regimes, which favor cold air outbreaks and upper air troughs.
Renewed growth of atmospheric methane
Authors: Rigby M. , Prinn R. G. , Fraser P. J. , Simmonds P. G. , Langenfelds R. L. , Huang J. , Cunnold D. M. , Steele L. P. , Krummel P. B. , Weiss R. F. , O'Doherty S. , Salameh P. K. , Wang H. J. , Harth C. M. , Mühle J. , Porter L. W.
Published: November 2008

Following almost a decade with little change in global atmospheric methane mole fraction, we present measurements from the Advanced Global Atmospheric Gases Experiment (AGAGE) and the Australian Commonwealth Scientific and Industrial Research Organisation (CSIRO) networks that show renewed growth starting near the beginning of 2007. Remarkably, a similar growth rate is found at all monitoring locations from this time until the latest measurements. We use these data, along with an inverse method applied to a simple model of atmospheric chemistry and transport, to investigate the possible drivers of the rise. Specifically, the relative roles of an increase in emission rate or a decrease in concentration of the hydroxyl radical, the largest methane sink, are examined. We conclude that: 1) if the annual mean hydroxyl radical concentration did not change, a substantial increase in emissions was required simultaneously in both hemispheres between 2006 and 2007; 2) if a small drop in the hydroxyl radical concentration occurred, consistent with AGAGE methyl chloroform measurements, the emission increase is more strongly biased to the Northern Hemisphere.
Nearly incompressible fluids: Decay of solar wind density fluctuations
Authors: Hunana P. , Zank G. P. , Heerikhuisen J. , Shaikh D.
Published: November 2008

The evolution of density fluctuations throughout the solar wind is investigated as the basis of a newly developed theory of nearly incompressible hydrodynamics for an inhomogeneous flow. The model is explored using two‐dimensional numerical simulations. The lowest‐order density fluctuations (absent in the original homogeneous nearly incompressible theory) obey a passive scalar evolution equation with an additional source term that results from coupling to the large‐scale inhomogeneous mean density gradient. The importance of this source term is explored, and we estimate analytically an upper bound for the maximum possible effect of a source term for nearly incompressible flows with an inhomogeneous background (static and spherically symmetric). For typical solar wind parameters, we show that this effect is rather weak beyond 0.1 AU and that the density fluctuations can be described sufficiently accurately as a pure passive scalar. Our simulations identify the sensitive dependence of density fluctuation evolution on typical initial length‐scale ratio of scalar (density) and velocity fields, an effect known from the theory of passive scalar decay and experimentally measured in grid‐generated turbulence. It has long been thought that the variance in the density fluctuations (δρ)2should decay in the manner analogous to the mean background density, implying that with heliocentric distance (δρ)2∝R−4throughout the heliosphere. Analysis of plasma data obtained by the Voyager spacecraft by Bellamy et al. (2005) showed that the density fluctuations decay much more slowly thanR−4and the decay rate exhibits a flattening between 20–30 AU and a possible rise afterward. A possible mechanism to reduce the decay rate within 30 AU was suggested to be turbulence driven by stream‐stream interactions followed by more dominant pickup ion interactions beyond 30 AU. Here we show that the variance in the density fluctuations as described by the inhomogeneous nearly incompressible theory evolves essentially independently of the mean density background with a decay rate that reduces and possibly levels off with increasing heliocentric distance.
Parameters of large‐scale TEC disturbances during the strong magnetic storm on 29 October 2003
Authors: Perevalova N. P. , Afraimovich E. L. , Voeykov S. V. , Zhivetiev I. V.
Published: November 2008

The total electron content (TEC) data obtained by the GPS network and GPS radio interferometry methods developed by the authors has made it possible to determine the spatial structure and dynamics parameters of large‐scale traveling ionospheric disturbances (LS TID) generated during the strong magnetic storm on 29 October 2003. It was shown that the LS TID registered in the auroral zone after a sudden storm commencement (SSC) represented a large‐scale solitary type wave with an annular front shape whose center was located near the geomagnetic pole. The wave had a period of about 40–60 min and traveled up to 4500 km equatorward. The relative amplitude of the LS TID was 5–10%. Comparison with ionosonde data has shown that this value corresponds to the relative amplitude of electron density disturbance in the F layer maximum of about 45–50%. The velocity and travel direction of the LS TID had a strongly pronounced longitudinal dependence. A “swirling” effect was detected in the LS TID movement, the direction of which was opposite to the Earth's rotation. The westward directed zonal projection of LS TID velocity caused this “swirling” effect. In the morning and evening sectors the zonal projection exceeded the meridional one. The diurnal movement of the ionization maximum may influence the zonal transfer of LS TID.
Changes in the longitudinal structure of the low‐latitude ionosphere during the July 2004 sequence of geomagnetic storms
Authors: Pedatella N. M. , Forbes J. M. , Lei J. , Thayer J. P. , Larson K. M.
Published: November 2008

In this brief report, the interplay between meteorological and geomagnetic activity influences on the low‐latitude ionosphere is studied. Specifically, the disruption of the dominant wave‐4 longitudinal structure of the equatorial ionization anomaly (EIA) by geomagnetic storms is investigated in connection with a sequence of three coronal mass ejections in July 2004. Observations of in situ electron density from the Challenging Minisatellite Payload (CHAMP) satellite are used to investigate changes in the longitudinal structure of the EIA during the different phases of the geomagnetic storms. The observed electron densities at ∼1200 local time during the initial‐main phases of the storms does not indicate significant longitudinal structure of the low‐latitude ionosphere. A wave‐4 structure of the EIA begins to reappear during the storm recovery phases although it is slightly weaker compared to undisturbed conditions. Although the upward propagating atmospheric tides responsible for generating the wave‐4 structure of the EIA are not influenced by the geomagnetic storms, changes in the electric fields, neutral winds, and neutral composition due to the geomagnetic storms serve to disrupt the longitudinal structure of the EIA. The results further indicate that the sampling longitude needs to be accounted for when using satellite observations at a fixed local time for geomagnetic storm studies.
Rice Convection Model simulation of the 18 April 2002 sawtooth event and evidence for interchange instability
Authors: Yang J. , Toffoletto F. R. , Wolf R. A. , Sazykin S. , Spiro R. W. , Brandt P. C. , Henderson M. G. , Frey H. U.
Published: November 2008

We present the results of a Rice Convection Model (RCM) simulation of the 18 April 2002 sawtooth event. This event occurred as a series of quasi‐periodic substorms during fairly stable solar wind conditions. It is modeled by (1) prescribing a solar‐wind‐driven magnetic field model (T01_s) augmented by additional current loops representing the magnetic effects of the substorm current wedge and (2) by carefully specifying a substorm‐phase‐dependent plasma distribution at the RCM outer boundary at 8 Re such that a hot and attenuated plasma distribution is used after every substorm onset. The set of input parameters was adjusted to make the simulation results agree with the primary signatures of the sawtooth event, specifically the sequence of magnetic field stretching and dipolarization observed by the GOES spacecraft and the associated sharp increases and gradual decreases in the flux of energetic protons measured by the LANL/Synchronous Orbit Plasma Analyzer (SOPA) instruments on other geosynchronous spacecrafts. The results suggest the important role that higher temperature and lower density plasma‐sheet plasma plays in producing flux enhancements at geosynchronous orbit. The results also confirm that induction electric fields associated with magnetic field collapse after substorm onsets can serve as a likely mechanism for the energization of particles up to 25 keV. Synthetic high‐energy neutral atom images are compared with IMAGE/HENA measurements for 10–60 keV hydrogen atoms. Magnetic field dipolarization over a large range of local time resulted in a dramatic reduction in the plasma entropy parameter PV5/3 on the boundary. The simulation indicates that the ring current intensified 10–20 minutes after every onset, associated with the injection of low PV5/3 flux tubes through the boundary. The low PV5/3 plasma also produced an interchange convection in the inner magnetosphere, which drives Birkeland currents in a quasi‐periodic upward‐downward pattern with a lifetime of 40–60 minutes and spatial extent of 1.5–2.0 hours. The results suggest that the spatial quasi‐periodic and nearly north–south‐aligned auroral arcs observed by an IMAGE/FUV WIC detector might be caused by interchange instability.
Shallow intraplate earthquakes in Western Australia observed by Interferometric Synthetic Aperture Radar
Authors: Dawson John , Cummins Phil , Tregoning Paul , Leonard Mark
Published: November 2008

We investigate two intraplate earthquakes in a stable continental region of southwest Western Australia. Both small‐magnitude events occur in the top ∼1 km of crust and their epicenters are located with an accuracy of ∼100 m (1σ) using satellite Interferometric Synthetic Aperture Radar (InSAR). For theMw4.7 Katanning earthquake (10 October 2007) the average slip magnitude is 42 cm, over a rupture area of ∼1 km2. This implies a high static stress drop of 14–27 MPa, even for this very shallow earthquake, which may have important implications for regional seismic hazard assessment. The earthquake rupture extends from a depth of around 640 m to the surface, making it a rarely observed intraplate, surface‐rupturing event. Using InSAR observations, we estimate the coseismic slip distribution of the shallow earthquake, such estimates being rarely available for small magnitude events. For theMw4.4 composite Kalannie earthquake sequence (21–22 September 2005), we use a long‐term time series analysis technique to improve the measurement of the co‐seismic signal, which is a maximum of 27 mm in the line‐of‐sight direction. Double difference seismic analysis shows some relocated cluster seismicity which corresponds in timing, location, and source parameters to the InSAR‐observed deformation. This earthquake is the smallest magnitude seismic event to have been investigated using InSAR and demonstrates the capability of the technique to provide important constraints on small‐magnitude coseismic events. The shallow depth of both these events adds weight to the suggestion that earthquakes associated with tectonic processes in this area of Western Australia often initiate in the upper 1 km of crust.
Synthetic Aperture Radar observations of resonantly generated internal solitary waves at Race Point Channel (Cape Cod)
Authors: da Silva J. C. B. , Helfrich K. R.
Published: November 2008

Synthetic Aperture Radar images revealed the two‐dimensional propagation characteristics of short‐period internal solitary waves in Race Point Channel in Massachusetts Bay. The images and in situ measurements of the flow in the channel are used to infer the likely generation mechanism of the waves. The solitary waves are generated during the ebb phase of the tide within the channel. On some occasions, two trains of internal waves are generated presumably at the same location but at slightly different phases of the ebb tide. The main characteristics of the (two‐layer) flow are described based on the criticality of the Froude number. It is suggested that these two individual packets of waves result from flow passage through resonance (where the Froude number is one). One packet is generated as the flow passes through the transcritical regime during the acceleration phase of the (ebb) tidal current, and another packet is generated during the deceleration phase. Both packets propagate upstream when the tide slacks, but with slightly different propagation directions.
First observations of turbulence generated by grass fires
Authors: Clements Craig B. , Zhong Shiyuan , Bian Xindi , Heilman Warren E. , Byun Daewon W.
Published: November 2008

Wildland fires radically modify the atmospheric boundary layer by inducing strong fire‐atmosphere interactions. These interactions lead to intense turbulence production in and around the fire front. Two field experiments were conducted in tall‐grass fuels to quantify turbulence generation during the passage of wind‐driven fire fronts. Observations showed that the measured turbulence generated by the fires was five times greater than the turbulence in the ambient environment. The production of the turbulence at the surface near the fire front was caused by increased variance of the ambient wind, while the buoyancy was strongest at higher levels within the fire plume. Immediately after the fire front passage, turbulence kinetic energy decreased to ambient levels and was associated with strong downdrafts that occurred behind the fire front.
Daily to submonthly weather and climate characteristics of the summer 1998 extreme rainfall over the Yangtze River Basin
Authors: Liu Hongbo , Zhang Da‐Lin , Wang Bin
Published: November 2008

In this study, the daily to submonthly weather and regional climate characteristics associated with the extreme rainfall events over the middle to lower reaches of the Yangtze River Basin (YRB‐ML) during the summer of 1998 are examined using the National Centers for Environmental Prediction/Department of Energy Reanalysis‐2 data and a 54‐day high‐resolution (i.e., Δx = 4 km) simulation with a regional climate model (RCM). As verified against various observations, the RCM reproduces reasonably well the accumulated daily to biweekly rainfall events, their generation and subsequent evolution along the Meiyu front, and especially the rainfall events over the YRB‐ML during the later stage of the 1998 floods. It is found that the early stage of the 1998 floods resembles in many aspects that occurred in normal years, except for a moister‐than‐climate state and stronger‐than‐normal low‐level jets (LLJs) in Southeast China, whereas the later stage exhibits two abnormal height anomalies to the northeast and southwest of the YRB‐ML, facilitating convergence of northeasterly and southwesterly flows along the Meiyu front. It is also found that the Meiyu front weakens in depth and intensity as it migrates northward across and then retreats to the YRB‐ML, playing less important roles in rain production. Results show different daily to biweekly rainfall characteristics at the different stages, e.g., from eastward propagation to local generation of mesoscale convective systems and periodical rain production along the Meiyu front, most of which reach their maximum intensities over the YRB‐ML during the morning to early afternoon hours. Results indicate that the northeasterly moisture supply enhances the production of steady heavy rain at the later stage of the 1998 floods. It is concluded that the West Pacific subtropical high and the Meiyu front control the general areas of rain production, the low‐level moisture supply through LLJs and mesoscale disturbances determines whether or not sustaining flooding rains would occur, and what rainfall characteristics are at the daily to biweekly timescales.
A method for smoke marker measurements and its potential application for determining the contribution of biomass burning from wildfires and prescribed fires to ambient PM2.5 organic carbon
Authors: Sullivan A. P. , Holden A. S. , Patterson L. A. , McMeeking G. R. , Kreidenweis S. M. , Malm W. C. , Hao W. M. , Wold C. E. , Collett J. L.
Published: November 2008

Biomass burning is an important source of particulate organic carbon (OC) in the atmosphere. Quantifying this contribution in time and space requires a means of routinely apportioning contributions of smoke from biomass burning to OC. Smoke marker (for example, levoglucosan) measurements provide the most common approach for making this determination. A lack of source profiles for wildfires and prescribed fires and the expense and complexity of traditional smoke marker measurement methods have thus far limited routine estimates of these contributions to ambient aerosol concentrations and regional haze. We report here on the collection of source profiles for combustion of numerous wildland fuels and on the development of an inexpensive and robust technique for routine smoke marker measurements. Hi‐Volume filter source samples were collected during two studies at the Fire Science Laboratory in Missoula, MT in 2006 and 2007. Levoglucosan (and other carbohydrates) were measured in these samples using high‐performance anion‐exchange chromatography with pulsed amperometric detection. Results of this analysis along with water‐soluble potassium, OC, and elemental carbon are presented. The results show that emissions of levoglucosan are fairly correlated with OC with an average ratio of 0.031 μg C/μg C. Further, there was a definite pattern that emerged based on fuel component burned with the typical levoglucosan/OC ratio of branches > straw > needles > leaves. Additionally, this carbohydrate measurement method appears to provide fingerprint information about the type of fuel burned that could help constrain profiles chosen for aerosol source apportionment and lead to a better determination of source contributions from biomass burning.
A new merged analysis of precipitation utilizing satellite and reanalysis data
Authors: Sapiano M. R. P. , Smith T. M. , Arkin P. A.
Published: November 2008

Many merged multi‐source global analyses of precipitation exist, including the Global Precipitation Climatology Project (GPCP) analysis and the CPC Merged Analysis of Precipitation. The multi‐source nature of these data sets allows them to use the most accurate type of inputs available to produce the best estimate of precipitation for any given place and time. However, studies have shown that the oceanic satellite estimates used in these data sets are less accurate at high latitudes when compared to reanalysis data. This study describes the Multi‐Source Analysis of Precipitation (MSAP), a new 2.5° gridded global analysis of precipitation from 1987 to 2002 using Optimum Interpolation (OI) based on the Defense Meteorological Satellite Program (DMSP) Special Sensor Microwave/Imager (SSM/I) and the forecast precipitation from the ERA‐40 reanalysis. The main goal of this new analysis is to produce a spatially consistent estimate using the same set of inputs over all regions and times rather than to have the lowest mean squared error. An advantage of the OI methodology is that it optimally merges the inputs based on pre‐defined weights and errors associated with the analysis that are directly estimated from the technique. Validation against other gridded data sets as well as tropical ocean and high‐latitude land gauges show that MSAP performs particularly well at high latitudes when compared to the satellite‐only part of GPCP. However, it contains negative biases in parts of the Northern Hemisphere because of the ERA‐40 data and large positive biases over tropical land areas due to issues with the SSM/I estimates. In the future, this new approach can be applied using precipitation estimates from the next generation reanalysis systems such as the JRA‐25, NASA's MERRA, and the ERA Interim reanalysis.
Relationships between global precipitation and surface temperature on interannual and longer timescales (1979–2006)
Authors: Adler Robert F. , Gu Guojun , Wang Jian‐Jian , Huffman George J. , Curtis Scott , Bolvin David
Published: November 2008

Associations between global and regional precipitation and surface temperature anomalies on interannual and longer timescales are explored for the period of 1979–2006 using the GPCP precipitation product and the NASA‐GISS surface temperature data set. Positive (negative) correlations are generally confirmed between these two variables over tropical oceans (lands). ENSO is the dominant factor in these interannual tropical relations. Away from the tropics, particularly in the Northern Hemisphere mid‐high latitudes, this correlation relationship becomes much more complicated with positive and negative values of correlation tending to appear over both ocean and land, with a strong seasonal variation in the correlation patterns. Relationships between long‐term linear changes in global precipitation and surface temperature are also assessed. Most intense long‐term, linear changes in annual‐mean rainfall during the data record tend to be within the tropics. For surface temperature however, the strongest linear changes are observed in the Northern Hemisphere mid‐high latitudes, with much weaker temperature changes in the tropical region and Southern Hemisphere. Finally, the ratios between the linear changes in zonal‐mean rainfall and temperature anomalies over the period are estimated. Globally, the calculation results in a +2.3%/°C precipitation change, although the magnitude is sensitive to small errors in the precipitation data set and to the length of record used for the calculation. The long‐term temperature‐precipitation relations are also compared to the interannual variations of the same ratio in a zonally averaged sense and are shown to have similar profiles, except for over tropical land areas.
Ice nucleation on mineral dust particles: Onset conditions, nucleation rates and contact angles
Authors: Eastwood Michael L. , Cremel Sebastien , Gehrke Clemens , Girard Eric , Bertram Allan K.
Published: November 2008

An optical microscope coupled to a flow cell was used to investigate the onset conditions for ice nucleation on five atmospherically relevant minerals at temperatures ranging from 233 to 246 K. Here we define the onset conditions as the humidity and temperature at which the first ice nucleation event was observed. Kaolinite and muscovite were found to be efficient ice nuclei in the deposition mode, requiring relative humidities with respect to ice (RHi) below 112% in order to initiate ice crystal formation. Quartz and calcite, by contrast, were poor ice nuclei, requiring relative humidities close to water saturation before ice crystals would form. Montmorillonite particles were efficient ice nuclei at temperatures below 241 K but were poor ice nuclei at higher temperatures. In several cases, there was a lack of quantitative agreement between our data and previously published work. This can be explained by several factors including the mineral source, the particle sizes, the surface area available for nucleation, and observation time. Heterogeneous nucleation rates (Jhet) were calculated from the measurements of the onset conditions (temperature and RHi) required from ice nucleation. The Jhet values were then used to calculate contact angles (θ) between the mineral substrates and an ice embryo using classical nucleation theory. The contact angles measured for kaolinite and muscovite ranged from 6° to 12°, whereas for quartz and calcite, the contact angles ranged from 25° to 27°. The reported Jhet and θ values may allow for a more direct comparison between laboratory studies and can be used when modeling ice cloud formation in the atmosphere.
Improved modeling of geomagnetically induced currents in the South African power network
Authors: Ngwira Chigomezyo M. , Pulkkinen Antti , McKinnell Lee‐Anne , Cilliers Pierre J.
Published: November 2008

Geomagnetically induced currents (GICs), resulting from adverse space weather, have been demonstrated to cause damage to power transformers in the midlatitudes. There is growing concern over possible GIC effects in the Southern African network because of its long power lines. Previous efforts to model the electric field associated with GICs in South Africa have used a uniform ground conductivity model. In an effort to improve the modeling of GICs, GIC data together with the Hermanus Magnetic Observatory geomagnetic field data were used in order to obtain a multilayered ground conductivity structure. The method requires a definition of the network coefficients, which are then used in subsequent calculations. This study shows that GIC computed using the new network coefficients and the multilayered ground conductivity model improves the accuracy of GIC modeling. GIC statistics are then derived on the basis of the recordings of the geomagnetic field from 1996 to 2006 at Hermanus, the new network coefficients, and ground conductivity model. The geoelectric field was modeled using the plane wave method.
Conduit evolution in deep‐seated settings: Conceptual and numerical models based on field observations
Authors: Rehrl C. , Birk S. , Klimchouk A. B.
Published: November 2008

To examine the interrelation between hydrogeological environment and conduit development in deep‐seated settings, a conceptual model is tested by numerical modeling. Based on field observations, simplified model settings are designed and crucial parameters are varied. A coupled continuum‐pipe flow model is employed for simulating conduit development within the soluble unit of a multilayer aquifer system. In agreement with field observations, the evolving cave patterns are characterized by pronounced horizontal passages and multiple vertical conduits at the bottom of the soluble unit but only few at the top. The frequency distribution of conduit diameters is found to be bimodal if the permeability of the rock formation is sufficiently high to allow competitive conduit development governed by the feedback between increasing flow and dissolution rates. This feedback, however, is suppressed in low‐permeability formations. As a consequence, conduit development is uniform rather than competitive.
Ambivalent Aspects of Interleukin-6 in Cerebral Ischemia: Inflammatory versus Neurotrophic Aspects
Authors: Suzuki Shigeaki , Tanaka Kortaro , Suzuki Norihiro
Published: November 2008

Interleukin-6 (IL-6) is pleiotropic cytokine involved in many central nervous system disorders including stroke, and elevated serum IL-6 has been found in acute stroke patients. IL-6 is implicated in the inflammation, which contributes to both injury and repair process after cerebral ischemia. However, IL-6 is one of the neurotrophic cytokines sharing a common receptor subunit, gp130, with other neurotrophic cytokines, such as leukemia inhibitory factor (LIF) and ciliary neurotrophic factor. The expression of IL-6 is most prominently identified in neurons in the peri-ischemic regions, and LIF expression shows a similar pattern. The direct injection of these cytokines into the brain after ischemia can reduce ischemic brain injury. The cytokine receptors are localized on the neuron surface, suggesting that neurons are the cytokine target. The major IL-6 downstream signaling pathway is JAK—STAT, and Stat3 activation occurs mainly in neurons during postischemic reperfusion. Further investigation is necessary to clarify the exact role of Stat3 signaling in neuroprotection. Taken together, the information suggests that IL-6 plays a double role in cerebral ischemia, as an inflammatory mediator during the acute phase and as a neurotrophic mediator between the subacute and prolonged phases.
An essential role for the Glut1 PDZ-binding motif in growth factor regulation of Glut1 degradation and trafficking
Authors: Wieman Heather L. , Horn Sarah R. , Jacobs Sarah R. , Altman Brian J. , Kornbluth Sally , Rathmell Jeffrey C.
Published: November 2008

Cell surface localization of the Glut (glucose transporter), Glut1, is a cytokine-controlled process essential to support the metabolism and survival of haemopoietic cells. Molecular mechanisms that regulate Glut1 trafficking, however, are not certain. In the present study, we show that a C-terminal PDZ-binding motif in Glut1 is critical to promote maximal cytokine-stimulated Glut1 cell surface localization and prevent Glut1 lysosomal degradation in the absence of growth factor. Disruption of this PDZ-binding sequence through deletion or point mutation sharply decreased surface Glut1 levels and led to rapid targeting of internalized Glut1 to lysosomes for proteolysis, particularly in growth factor-deprived cells. The PDZ-domain protein, GIPC (Gα-interacting protein-interacting protein, C-terminus), bound to Glut1 in part via the Glut1 C-terminal PDZ-binding motif, and we found that GIPC deficiency decreased Glut1 surface levels and glucose uptake. Unlike the Glut1 degradation observed on mutation of the Glut1 PDZ-binding domain, however, GIPC deficiency resulted in accumulation of intracellular Glut1 in a pool distinct from the recycling pathway of the TfR (transferrin receptor). Blockade of Glut1 lysosomal targeting after growth factor withdrawal also led to intracellular accumulation of Glut1, a portion of which could be rapidly restored to the cell surface after growth factor stimulation. These results indicate that the C-terminal PDZ-binding motif of Glut1 plays a key role in growth factor regulation of glucose uptake by both allowing GIPC to promote Glut1 trafficking to the cell surface and protecting intracellular Glut1 from lysosomal degradation after growth factor withdrawal, thus allowing the potential for a rapid return of intracellular Glut1 to the cell surface on restimulation.
Pulsed tunneling maps out an electron system’s density of states
Authors: Day Charles
Published: November 2008

Landau levels, spin splitting, and other features of a quantum Hall system come sharply into view when electrons tunnel through a tiny capacitor.
Stromboli volcano’s explosions have deep origins
Authors: Miller Johanna
Published: November 2008

Real-time spectroscopic measurements of emitted gases probe activity far beneath the surface.
Big boost in science funding authorized by Congress
Authors: Dawson Jim
Published: November 2008

Congress authorized billions of dollars more for science than the president requested. But authorizing is not the same as appropriating, and skeptics are saying “show me the money.”
Phase-transition dynamics in the lab and the universe
Authors: Kibble Tom
Published: November 2008

Topological defects, such as vortices and flux tubes, that arise during phase transitions in condensed-matter systems can serve as models for a far more elusive defect—cosmic strings formed in the early universe.
The diverse world of liquid crystals
Authors: Palffy-Muhoray Peter
Published: November 2008

Orientationally ordered soft matter is exceptionally responsive to a variety of excitations. That’s the basis for its great range of applications.
Growth of di-indenoperylene single crystals on amino-functionalized SiO2 surfaces
Authors: Zhang Xue Na , Barrena Esther , Garcia de Oteyza Dimas , De Souza Emerson , Dosch Helmut
Published: November 2008

We report a combined atomic force microscopy/x-ray diffraction study of the growth and dewetting of the organic molecule di-indenoperylene (DIP) on SiO2 surfaces that have been functionalized with an amino-terminated self-assembled monolayer of 3-aminopropyltriethoxysilane [APS, (CH3CH2O)3Si(CH2)3NH2]. We disclose a transition of DIP thin films from two-dimensional to three-dimensional growth at 80 °C, which is associated with a change in the surface morphology of APS during the annealing of the substrates. This growth scenario gives rise to the formation of micron sized DIP single crystals, which could be potentially interesting for future application in electronic devices.
Optical and structural properties of Li2O–Al2O3–B2O3 glasses before and after γ-irradiation effects
Authors: Singh D. , Singh K. , Bajwa B. S. , Mudahar G. S. , Singh D. P. , Manupriya  , Arora M. , Dangwal V. K.
Published: November 2008

The density, molar volume, optical energy bandgap, and infrared absorption spectra in the range 400–4000 nm of borate glasses with composition 2xLi2O–xAl2O3–(1–3x)B2O3 (x varying from 0.10 to 0.18 mol fraction) prepared by conventional melt quench technique have been measured before and after successive γ-ray irradiation at the dose of 2.5 K Gy to elucidate the effect of gamma irradiation on such glasses. The radiation induced defects created by γ-ray and the changes in optical properties have been discussed.
Raman spectra analysis for Ca(B1/3′B2/3″)O3-based complex perovskite ceramics
Authors: Fu M. S. , Liu X. Q. , Chen X. M.
Published: November 2008

Ca [ ( Mg 1 / 3 Ta 2 / 3 ) 1 − x Ti x ] O 3 (hereafter denoted as CMTT) and (Ca1−0.39xNd0.26x) [(Mg1/3Nb2/3)1−xTix]O3 (hereafter denoted as CNMNT) complex perovskite ceramics were studied by Raman spectroscopy combined with Rietveld analysis. The crystal structures changed from monoclinic structure with P21/c space group to orthorhombic structure with Pbnm space group for both systems. The main structure of the two systems was orthorhombic and the characteristic modes for the orthorhombic structure with space group Pbnm could be found in all the compositions. Raman modes at around 408 cm−1 could only be found for compositions with 1:2 long range cation ordering while modes at around 800 cm−1 could be found for all the compositions in both systems. They were concluded to be correlated with the 1:2 long range cation ordering and different short range cation ordering, respectively. Two Ag modes at around 800 cm−1 represented for 1:2 and 1:1 short range cation ordering were observed for CMTT ceramics with x=0.1–0.6 while only 1:2 short range Ag mode was observed in all compositions for CNMNT ceramics. The weak A-O hybridization was considered to be the reason for the absence of the 1:1 short range cation ordering. The short range cation ordering was suggested to be appreciably beneficial to the Qf value.
Equilibrium and nonequilibrium thermodynamics of particle-stabilized thin liquid films
Authors: Bławzdziewicz J. , Wajnryb E.
Published: November 2008

Our recent quasi-two-dimensional thermodynamic description of thin liquid films stabilized by colloidal particles is generalized to describe nonuniform equilibrium states of films in external potentials and nonequilibrium transport processes produced in the film by gradients of thermodynamic forces. Using a Monte Carlo simulation method, we have determined equilibrium equations of state for a film stabilized by a suspension of hard spheres. Employing a multipolar-expansion method combined with a flow-reflection technique, we have also evaluated the short-time film-viscosity coefficients and collective particle mobility.
Melnikov theory to all orders and Puiseux series for subharmonic solutions
Authors: Corsi Livia , Gentile Guido
Published: November 2008

We study the problem of subharmonic bifurcations for analytic systems in the plane with perturbations depending periodically on time, in the case in which we only assume that the subharmonic Melnikov function has at least one zero. If the order of zero is odd, then there is always at least one subharmonic solution, whereas if the order is even, in general, other conditions have to be assumed to guarantee the existence of subharmonic solutions. Even when such solutions exist, in general, they are not analytic in the perturbation parameter. We show that they are analytic in a fractional power of the perturbation parameter. To obtain a fully constructive algorithm which allows us not only to prove existence but also to obtain bounds on the radius of analyticity and to approximate the solutions within any fixed accuracy, we need further assumptions. The method we use to construct the solution—when this is possible—is based on a combination of the Newton–Puiseux algorithm and the tree formalism. This leads to a graphical representation of the solution in terms of diagrams. Finally, if the subharmonic Melnikov function is identically zero, we show that it is possible to introduce higher order generalizations, for which the same kind of analysis can be carried out.
Low Schottky barrier height for ErSi2−x/n-Si contacts formed with a Ti cap
Authors: Reckinger Nicolas , Tang Xiaohui , Bayot Vincent , Yarekha Dmitri A. , Dubois Emmanuel , Godey Sylvie , Wallart Xavier , Larrieu Guilhem , Łaszcz Adam , Ratajczak Jacek , Jacques Pascal J. , Raskin Jean-Pierre
Published: November 2008

In this paper, the formation of Er disilicide (ErSi2−x) with a Ti cap on low doping n-type Si(100) is investigated. After deposition in ultrahigh vacuum, the solid-state reaction between Er and Si is performed ex situ by rapid thermal annealing between 450 and 600 °C in a forming gas ambience with a 10 nm thick Ti capping layer to protect Er from oxidation. X-ray diffraction analyses have confirmed the formation of ErSi2−x for all annealing temperatures. The formed films are found to be free of pinholes or pits and present a sharp and smooth interface with the Si bulk substrate. The extracted Schottky barrier height (SBH) corresponds to the state-of-the-art value of 0.28 eV if the annealing temperature is lower than or equal to 500 °C. This result demonstrates the possibility to form low SBH ErSi2−x/n-Si contacts with a protective Ti cap. However, when the annealing temperature is set to a higher value, the SBH concomitantly rises. Based on our experiments, this SBH increase can be mainly related to an enhanced diffusion of oxygen through the stack during the annealing, which degrades the quality of the ErSi2−x film.
Coherence resonance induced by colored noise near Hopf bifurcation
Authors: Ma Juan , Xiao Tiejun , Hou Zhonghuai , Xin Houwen
Published: November 2008

Effects of colored noise near supercritical Hopf bifurcation, especially noise induced oscillation (NIO) and coherence resonance (CR), have been studied analytically in the Brusselator model, using the stochastic normal form method. Two types of colored noise are considered: one is the standard Gaussian colored noise generated by the Ornstein–Uhlenbeck (OU) process and the other is the so-called power-limited (PL) process. Depending on the noise intensity and noise type, it is found that the autocorrelation time, most probable radius and signal to noise ratio of the NIO may show nontrivial dependencies on the noise correlation time τc. Interestingly, for OU-type noise with intensity above a threshold, SNR is a bell-shaped function of τc, indicating enhancement of CR by noise correlation; and for PL-type noise, SNR may show double maxima when τc is changed, demonstrating a new kind of multiresonance phenomenon. These theoretical predictions are well reproduced by numerical simulations.
Electronic properties of (Ga,Mn)N thin films with high Mn content
Authors: Granville S. , Ruck B. J. , Preston A. R. H. , Stewart T. , Budde F. , Trodahl H. J. , Bittar A. , Downes J. E. , Ridgway M.
Published: November 2008

Optical and dc resistivity measurements as well as x-ray spectroscopies have been performed on (Ga,Mn)N films containing Mn at up to 11 at. %. The results indicate that at higher Mn contents, the Fermi level is situated within extended states, while GaN host interband optical transitions are unaffected. The Mn state is confirmed to be 3d5, as in the case of lower Mn content films; however, the high Mn content merges the 3d levels into a band located just below the host conduction band. The Fermi level is located within these Mn states just below the conduction band, in sharp contrast to its midgap position in fully crystalline, low Mn concentration materials. The difference in the position of the Fermi level at high Mn dopant levels has important implications for the promotion of ferromagnetism in this material.