bluuebunny/crossref_metadata_2025 huggingface dataset:
Prävalenz von Übergewicht und Adipositas bei KantonsschülerInnen in St. Gallen
Authors: Bärlocher A. , Vetter W. , Suter P.M.
Published: February 2008

Übergewicht und Adipositas stellen die wichtigsten Modulatoren des Risikos der chronischen Erkrankungen dar. In dieser Studie sollen mögliche Determinanten und die Prävalenz von Übergewicht und Adipositas bei KantonsschülerInnen evaluiert werden. Bei 552 Schülerinnen und Schülern der Kantonsschule am Burggraben (St. Gallen) wurden anthropometrische Parameter (z.B. Körpergrösse, Gewicht, Taillenumfang, Hüftumfang, Körperzusammensetzung mittels Bioimpedanz) gemessen und Lebensstilcharakteristika mittels eines Fragebogens erfasst. Unter Verwendung der IOTF-Definitionskriterien waren in Abhängigkeit des Geschlechts 6.12– 8.18% übergewichtig und 1.08–2.23% adipös. Das Ausmass der körperlichen Aktivität sowie des Medienkonsums spielten in Abhängigkeit vom Geschlecht eine unterschiedliche Rolle. Schüler mit dem höchsten Medienkonsum wiesen einen höheren BMI und einen höheren Körper-Fettanteil auf als Schüler mit mittlerem oder geringem Medienkonsum. Bei den Schülerinnen zeigte sich keine Abhängigkeit des BMI oder des Fettanteiles vom Medienkonsum. Schüler mit hoher körperlicher Aktivität zeigten einen signifikant tieferen BMI als Schüler mit geringer körperlicher Aktivität auch der Fettanteil war bei hoher körperlicher Aktivität tiefer. Bei den Schülerinnen wurde der Fettanteil, nicht jedoch der BMI, von der körperlichen Aktivität determiniert. Zumal die Risikofaktoren für die Entwicklung des Übergewichtes oftmals bereits in der Kindheit und Jugend entstehen und ins Erwachsenenalter übernommen werden, ist frühzeitige Prävention von zentraler Bedeutung.
North American climate of the last millennium: Underground temperatures and model comparison
Authors: Stevens M. Bruce , González‐Rouco J. Fidel , Beltrami Hugo
Published: February 2008

General circulation models (GCMs) are currently able to provide physically consistent simulations of millennial climate variability in which estimations of external forcing factors are incorporated as boundary conditions. Climate reconstruction attempts to recover as faithfully as possible past climate variability using a variety of independent and climate‐sensitive sources of information. By deriving strategies of comparison between GCM simulations and proxy data, or directly recorded data such as subsurface thermal profiles, the agreement between model and observations can be assessed. Thermal profiles obtained from the boreholes of North America were grouped into eight geographically discrete ensembles and averaged to form robust, representative profiles. The gridded output from the three distinct integrations of the GCM ECHO‐g were similarly averaged by region. These simulated, millennial, paleoclimatic histories were then forward modeled to arrive at the subsurface thermal profiles that would result from the temperature trends at the surface. These forward modeled profiles were then compared with the borehole average thermal anomaly profile in each region. In most of the regions studied, the externally forced runs from ECHO‐g are in better agreement with underground temperature anomalies than with the control run, suggesting that boreholes are sensitive to external forcing. Not only do ECHO‐g simulations demonstrate better agreement with borehole data when considering variable external forcing factors, but ECHO‐g also appears to broadly describe qualitative aspects of long‐term climatic trends at a regional scale.
A flume experiment on the formation of wood jams in rivers
Authors: Bocchiola D. , Rulli M. C. , Rosso R.
Published: February 2008

A flume experiment is carried out to explore jamming of Large Woody Debris (LWD) in streams with complex morphology, occurring in mountain streams with in channel boulders or vegetation, in braided rivers or in floodplains during flood events. Non rooted, defoliated LWD is modeled using wood dowels and obstacles to motion are represented by vertical wood rods. Congested transport of LWD is simulated by insertion of a number (100) of dowels. The final position of the dowels is mapped and the observed jams are classified according to their size and position. The key member of each jam is identified and its trapping mechanism evaluated, either by leaning against a single obstacle or by bridging two obstacles. To mimic uncongested transport, the experiment is repeated for single pieces of wood, with subsequent removal. Longer dowels and shallower water result in shorter traveled distance. Wood pieces travel farther when congested transport is observed. The traveled distance of the wood pieces can be modeled using a Gamma distribution, for both congested and uncongested transport. Jams instead display Uniform traveled distance. The number of pieces displays an Exponential distribution. The degree of uniformity in space of jams and wood pieces is evaluated using a neighbor K statistic. Wood pieces show considerable clustering, while jams show sparse distribution. Eventually, the relationship between jams magnitude and position is explored, showing negative correlation. Model application is then discussed and some conclusions and future developments are outlined.
Chemical weathering and chemical denudation dynamics through ecosystem development and disturbance
Authors: Balogh‐Brunstad Zsuzsanna , Keller C. Kent , Bormann Bernard T. , O'Brien Rachel , Wang Deane , Hawley Gary
Published: February 2008

Mineral weathering and chemical denudation of terrestrial environments are understood by both geochemists and ecologists to be affected by rooted plant growth. We used unique 20‐year “sandbox” experiments to test the predictions of both disciplines regarding the influence of tree growth and harvest on chemical weathering and denudation of Ca2+, Mg2+ and K+. Results showed 3 temporal phases: 1) weathering‐dominated rapid uptake of mineral nutrients with retention in trees and soil, and low denudation; 2) biocycling‐dominated nutrient uptake with slower tree growth, and chemical fluxes reduced to near zero; and 3) denudation‐dominated loss of nutrient reserves after harvest by disruption of biotic regulation. Overall, a red pine sandbox used and retained its resources more effectively than a reference non‐vascular system. The results suggest that disturbance may be an important factor controlling chemical denudation rates. Temporal variations of the fluxes highlight difficulties of extrapolating weathering and denudation rates over long timescales.
High‐resolution Al and Fe data from the Atlantic Ocean CLIVAR‐CO2 Repeat Hydrography A16N transect: Extensive linkages between atmospheric dust and upper ocean geochemistry
Authors: Measures C. I. , Landing W. M. , Brown M. T. , Buck C. S.
Published: February 2008

Trace element sampling and shipboard flow injection analysis during the June–August 2003 Climate Variability and Predictability (CLIVAR)‐CO2 Repeat Hydrography A16N transect has produced a high‐resolution section of dissolved Fe and Al in the upper 1000 m of the Atlantic Ocean between 62°N and 5°S. Using the surface water dissolved Al and the Model of Aluminum for Dust Calculation in Oceanic Waters (MADCOW) model we have calculated the deposition of mineral dust to the surface ocean along this transect and compare that to dissolved Fe concentrations. The lowest mean mineral dust depositions of ≤0.2 g m−2 a−1 are found to the north of 51°N; a region which also exhibits characteristics of biological Fe limitation through its low dissolved surface water Fe (∼0.1 nM) and residual macronutrients, e.g., nitrate >2 μM. To the south of this region, mean dust deposition increases by an order of magnitude reaching ∼3 g m−2 a−1 at 10°N, underneath the Saharan dust outflow. Surface water Fe values also increase along this section to >1 nM. Distinct minima in Fe concentrations at the depth of the chlorophyll maximum in the vertical profiles between 18 and 4°N illuminate the role that active biological uptake plays in Fe cycling. An extensive subsurface zone of enhanced dissolved Fe concentrations (>1.5 nM) underlying this region is a result of the biological vertical transport and remineralization of the surface water Fe and is coincident with the intermediate nutrient maximum and oxygen minimum of this region. Elevated concentrations of dissolved Al in subsurface waters seen between 30 and 20°N coincide with the domain of the subtropical mode waters (STMW) which result from the sinking of surface waters in late winter in regions imprinted by dust deposition. The magnitude of the Al enrichment observed in this water mass implies that the predominant source to the STMW is from the more dust‐impacted western Atlantic, with only limited contributions from the STMW formation region near Madeira. A deeper subsurface Al enrichment (30–45°N) is associated with the outflow from the Mediterranean, another heavily dust‐impacted basin. These two regions of Al enrichment show the widespread geochemical connection between atmospheric transport processes and the North Atlantic and underscore its susceptibility to imprinting by atmospherically borne materials, natural as well as anthropogenic.
Excess sediment 230Th: Transport along the sea floor or enhanced water column scavenging?
Authors: Broecker Wallace
Published: February 2008

The sedimentary inventory of 230Th is often employed to distinguish between areas which receive excess sediment as the result of along‐bottom transport from those which lose sediment as a result of winnowing. This process is referred to as “focusing.” A case is made here that, at least in the western equatorial Pacific, the excess 230Th in on‐equator sediment is more likely scavenged from the overlying water column by the rain of organic matter than retransported along the bottom. If so, lateral variations in biological productivity may well contribute to the excess 230Th inventories elsewhere as well.
Investigation of dynamical processes in the polar stratospheric vortex during the unusually cold winter 2004/2005
Authors: El Amraoui L. , Semane N. , Peuch V.‐H. , Santee M. L.
Published: February 2008

The 2004/2005 Arctic winter was unusually cold with high potential for Polar Stratospheric Clouds formation. We use O3 and N2O assimilated fields from Aura/MLS in order to describe the dynamical processes inside the polar vortex during this winter. The evolution of N2O assimilated field shows that subsidence was the dominant dynamical process between early December and late January. The mixing effect between the polar vortex and midlatitudes has been diagnosed using the effective diffusivity parameter. It shows that from early February to the end of March, mixing was dominant compared to diabatic descent. The vortex‐averaged ozone loss profile from O3 assimilated field shows a maximum of ∼1.5 ppmv at 425 K, which is less pronounced compared to other winters of similar meteorological conditions (e.g., 1999/2000). This is due to the importance of the mixing processes between the polar vortex and midlatitudes which bring in ozone‐rich air to the vortex.
Change in the Indonesian Throughflow with the climatic shift of 1976/77
Authors: Wainwright Lana , Meyers Gary , Wijffels Susan , Pigot Lidia
Published: February 2008

A climate shift occurred in 1976 with Pacific equatorial temperatures experiencing a sharp rise and was first identified as a change in the background state of the El Niño Southern Oscillation. The associated weakening of easterly trade winds across the Pacific led to our hypothesis that the Indonesian Throughflow (ITF) had also weakened. The change in volume transport of ITF before and after December 1975 was estimated using all the available subsurface temperature data on the IX1 expendable bathythermograph (XBT) line between Australia and Indonesia. Sea surface temperature (SST) rose by 1–2°C, which could be due to increased air‐sea heat flux and/or a change in regional circulation. A subsurface cooling in the main thermocline was attributed to a weakening of the Pacific trade winds. The South Equatorial Current (SEC) diminished in size and weakened in strength. The net westward volume transport between Australia and Indonesia showed a decrease of ∼2.5 Sverdrups, or 23%.
Variability in the Slope Water and its relation to the Gulf Stream path
Authors: Peña‐Molino B. , Joyce T. M.
Published: February 2008

Sea Surface Temperature (SST) and Sea Surface Height (SSH) data for 1993–2007 for the North Atlantic are combined with hydrographic data at 69W to investigate the relation between the Gulf Stream (GS) position and the Slope Water properties. SST anomalies north of the GS are correlated with changes in its path. The lag of this correlation is such that positive temperature anomalies precede northward shifts of the GS, and suggests that SST anomalies move westward with speeds of several cm/s. EOF analysis of the SST and SSH fields shows that cooling and strengthening of the SW flow are in phase over the Slope Water, which is mirrored in the vertical structure of these fields at 69W, indicating larger transports in the Deep Western Boundary Current lead to southward shifts of the mean GS path. This relation between the Slope Water and the GS path provides some predictability for the latter.
Atmospheric contribution of gas emissions from Augustine volcano, Alaska during the 2006 eruption
Authors: McGee K. A. , Doukas M. P. , McGimsey R. G. , Neal C. A. , Wessels R. L.
Published: February 2008

Airborne surveillance of gas emissions from Augustine for SO2, CO2 and H2S showed no evidence of anomalous degassing from 1990 through May 2005. By December 20, 2005, Augustine was degassing 660 td−1 of SO2, and ten times that by January 4, 2006. The highest SO2 emission rate measured during the 2006 eruption was 8650 td−1 (March 1); for CO2, 13000 td−1 (March 9), and H2S, 8 td−1 (January 19). Thirty‐four SO2 measurements were made from December 2005 through 2006, with 9 each for CO2 and H2S. Augustine released 1 × 106 tonnes of CO2 to the atmosphere during 2006, a level similar to the output of a medium‐sized natural gas‐fired power plant, and thus was not a significant contributor of greenhouse gas to the atmosphere compared to anthropogenic sources. Augustine released about 5 × 105 tonnes of SO2 during 2006, similar to that released in 1976 and 1986.
Tundra lake changes from 1978 to 2001 on the Tuktoyaktuk Peninsula, western Canadian Arctic
Authors: Plug L. J. , Walls C. , Scott B. M.
Published: February 2008

Landsat scenes spanning 1978–2001 were used to classify thermokarst lake area and determine changes in lake coverage on the Tuktoyaktuk Peninsula in northwestern Canada. Changes in total lake area between scenes were substantial, spanning a 14% increase and 11% decrease, mostly owing to changes in the area of lakes >1.3 km2 in area. Increases in total lake area occurred primarily between 1978–1992, and decreases between 1992–2001. Differences in total lake area between scenes from different years depend strongly on cumulative precipitation in the 12 month period preceding scene acquisition (r2 = 0.82), and not on summer or mean annual air temperature (MAAT). Our results indicate that precipitation is the primary factor influencing the areal extent of lakes as detected by remote sensing. On the Tuktoyaktuk Peninsula, persistent lake area changes (if any) such as might occur by regional warming or changes in evaporation/precipitation balance over decades, are well‐masked by short‐term climatological changes.
Indian Ocean Rossby waves detected in HYCOM sea surface salinity
Authors: Heffner David M. , Subrahmanyam Bulusu , Shriver Jay F.
Published: February 2008

Rossby waves have been well identified in satellite derived sea surface height (SSH), sea surface temperature (SST) and ocean color observations. Studies of Rossby waves have yet to include sea surface salinity (SSS) as a parameter, largely because presently available in situ measurements of salinity lack sufficient spatial and temporal coverage, and as of now no methods are available for measuring salinity from a satellite. In this paper, we demonstrate that Rossby waves can be observed in SSS in the Indian Ocean by using simulations of the 1/12° global Hybrid Coordinate Ocean Model (HYCOM). HYCOM results compared favorably to SSS data provided by Argo floats and the World Ocean Atlas 2005 (WOA05) in selected grid boxes in the Indian Ocean. Hovmöller diagrams of HYCOM SSS anomalies and gradient show the distinct westward propagating signature of Rossby waves, with a steeper slope in longitude/time plots further from the equator. The propagation speeds, calculated from a 2D Radon Transform are comparable with new theoretical speeds for Rossby waves. Annual westward propagating signals in the SSS simulations at most of the latitudes in the Indian Ocean coincide with previous studies. We hope that future studies of Rossby waves in SSS using model results and eventually satellite measurements of salinity data will allow a better understanding of Rossby wave dynamics.
Vertical structure of tropical oceanic convective clouds and its relation to precipitation
Authors: Kubar Terence L. , Hartmann Dennis L.
Published: February 2008

Cloudsat cloud radar data are used to investigate the vertical structure of cloud systems of the ITCZ across the West and East Pacific and its contribution to precipitation. Cloud radar data are collocated with precipitation rates from the Advanced Microwave Scanning Radiometer (AMSR) to examine differences in cloud top PDFs for different rain rate regimes. Heavily precipitating clouds have high tops that are nearly two km deeper than moderately raining or non‐raining high clouds. Rain rate increases with cloud height, especially for clouds higher than 12 km, with nearly a tenfold rain rate increase from 12 km to the tropical tropopause. Clouds with tops below 9.5 km contribute 38% to total rainfall in the West Pacific and 47% in the East Pacific, but they contribute 60% and 74% to total rain area, respectively.
Validation of GOMOS‐Envisat vertical profiles of O3, NO2, NO3, and aerosol extinction using balloon‐borne instruments and analysis of the retrievals
Authors: Renard Jean‐Baptiste , Berthet Gwenaël , Brogniez Colette , Catoire Valery , Fussen Didier , Goutail Florence , Oelhaf Hermann , Pommereau Jean‐Pierre , Roscoe Howard K. , Wetzel Gerald , Chartier Michel , Robert Claude , Balois Jean‐Yves , Verwaerde Christian , Auriol Frédérique , François Philippe , Gaubicher Bertrand , Wursteisen Patrick
Published: February 2008

The UV‐visible Global Ozone Monitoring by Occultation of Stars (GOMOS) instrument onboard Envisat performs nighttime measurements of ozone, NO2, NO3 and of the aerosol extinction, using the stellar occultation method. We have conducted a validation exercise using various balloon‐borne instruments in different geophysical conditions from 2002 to 2006, using GOMOS measurements performed with stars of different magnitudes. GOMOS and balloon‐borne vertical columns in the middle stratosphere are in excellent agreement for ozone and NO2. Some discrepancies can appear between GOMOS and balloon‐borne vertical profiles for the altitude and the amplitude of the concentration maximum. These discrepancies are randomly distributed, and no bias is detected. The accuracy of individual profiles in the middle stratosphere is 10 % for ozone and 25 % for NO2. On the other hand, the GOMOS NO3 retrieval is difficult and no direct validation can be conducted. The GOMOS aerosol content is also well estimated, but the wavelength dependence can be better estimated if the aerosol retrieval is performed only in the visible domain. We can conclude that the GOMOS operational retrieval algorithm works well and that GOMOS has fully respected its primary objective for the study of the trends of species in the middle stratosphere, using the profiles in a statistical manner. Some individual profiles can be partly inaccurate, in particular in the lower stratosphere. Improvements could be obtained by reprocessing some GOMOS transmissions in case of specific studies in the middle and lower stratosphere when using the individual profiles.
Analysis of radar sea return for breaking wave investigation
Authors: Hwang Paul A. , Sletten Mark A. , Toporkov Jakov V.
Published: February 2008

Low‐grazing angle backscattering data collected by a coherent dual‐polarized radar installed on a fixed tower in the ocean are analyzed to investigate the properties of sea spikes attributable to wave breaking. The distribution of breaking wave speed is narrow‐banded with an average speed between 2.0 and 2.6 m/s in mixed seas with wind speeds between 7 and 14.5 m/s. The corresponding breaking wavelength is between 2.5 and 4.3 m. The length or velocity scale of wave breaking is not proportional to the length or velocity scale of the dominant wave. This observation reflects the localized nature of the breaking process and may have significant implications on quantifying various breaking properties such as the energy dissipation or area of turnover by breaking waves. The fraction of sea spike coverage generally increases with wind speed but the trend of increase is modified by the intensity and relative direction of background swell. Parameterizations of sea spike coverage needs to take into consideration both wind and wave factors. Similarities and differences between sea spikes and whitecaps are discussed. In particular, while both quantities show a similar power law dependence on wind speed, the fraction of sea spike coverage is considerably higher than that of whitecap coverage. This result reflects the prevalence of steep features that produce quasi‐specular facets and short‐scale waves bounded to intermediate waves during breaking. These quasi‐specular facets and bound waves contribute significantly to enhancing the radar sea return but may not entrain air to produce whitecap signature.
Studying coastal recirculation with a simplified analytical land‐sea breeze model
Authors: Levy Ilan , Dayan Uri , Mahrer Yitzhak
Published: February 2008

The diurnal cycle of the land and sea breeze is of high importance in determining many aspects of the living conditions in coastal areas. One of these aspects is the buildup of air pollutants concentrations due to air mass recirculation. In order to study the main factors governing the recirculation of an air mass under land‐sea breeze conditions, a single station characterization of the recirculation potential in an airshed is implemented using a simplified land‐sea breeze analytical model. The factors studied are latitude, ambient wind intensity, breeze intensity and friction. A sensitivity analysis performed reveals that the highest potential for coastal recirculation exists around latitude 30° with low friction values. It is found that the combined effect of latitude, breeze intensity and the meridional component of the ambient wind has the biggest influence on the model and is responsible for 31% of its variance. Also, latitude and breeze intensity account each for about 20% of the variance. The recirculation model is found to be highly sensitive to latitude, particularly in mid latitudes and to breeze intensity for weak breeze winds. The performance of the recirculation model is compared to 5‐year measurements of recirculation at the East Mediterranean Sea during typical summer conditions. In spite of its rudimentary nature, the model does succeed in giving good quantitative measure of the recirculation, in the order of 0.3 on a scale of 0–1, very close to the observed values in the region.
Constraints from finite element modeling on the active tectonics of northern Central America and the Middle America Trench
Authors: Álvarez‐Gómez José A. , Meijer Paul T. , Martínez‐Díaz José J. , Capote Ramón
Published: February 2008

We have developed an elastic finite element model in order to study the role of the different forces acting on the northwestern part of the Central American Volcanic Arc and the Chortis Block. We present synthetic focal mechanisms, maps of tectonic regime, and strain crosses to analyze the results. The models show that to achieve the observed state of stress on the volcanic arc, the arc must be modeled as a lithospheric weak zone. Also, the forces related to the eastward drift of the Caribbean plate must be higher than those related to the subduction of the Cocos plate. The coupling on the subduction interface must be low, with or without slip‐partitioning due to the obliquity of the subduction at the trench. At Guatemala the western edge of the Chortis block is pinned against North America, even with low trench‐normal forces, making the triple junction between the Cocos, North American, and Caribbean plates a zone of diffuse deformation. The extension in the western part of the Chortis block, from Guatemala to the Honduras depression, is explained by the geometry of the North American‐Caribbean plate boundary and the direction of motion of the Caribbean plate with respect to North America. The direction of extension in the Chortis block is always E‐W regardless of the magnitude of the applied forces, and the main part of the deformation is absorbed between the Ipala graben and the Honduras depression, both features being consistent with our models.
Nonmonotonic traveling wave solutions of infiltration into porous media
Authors: DiCarlo David A. , Juanes Ruben , LaForce Tara , Witelski Thomas P.
Published: February 2008

In uniform soils that are susceptible to unstable preferential flow, the water saturation may exhibit a nonmonotonic profile upon continuous infiltration. As this nonmonotonicity (also known as saturation overshoot) cannot be described by the conventional Richards equation, there have been proposed possible extensions to the unsaturated flow equations, including a nonmonotonic capillary pressure–saturation curve and a second‐order hyperbolic term. Here, we present analytic traveling wave solutions to the extended Richards equation. These new solutions indeed display a nonmonotonic saturation profile, similar to previous simulation results. We show that these extensions need a regularization term to produce a unique solution. We develop complete analytic solutions using a relaxation regularization term, and we discuss the results in terms of recent measurements of saturation overshoot.
Estimating the soil temperature profile from a single depth observation: A simple empirical heatflow solution
Authors: Holmes T. R. H. , Owe M. , De Jeu R. A. M. , Kooi H.
Published: February 2008

Two field data sets are used to model near‐surface soil temperature profiles in a bare soil. It is shown that the commonly used solutions to the heat flow equations by Van Wijk perform well when applied at deeper soil layers, but result in large errors when applied to near surface layers, where more extreme variations in temperature occur. The reason for this is that these approaches do not consider heat sources or sinks below the surface. This paper proposes a new approach for modeling the surface soil temperature profiles from a single observation depth. This approach consists of two parts: 1) modeling an instantaneous ground flux profile based on net radiation and the ground heat flux at 5 cm depth; and 2) use of this ground heat flux profile to extrapolate a single temperature observation to a complete surface temperature profile. The new model is validated under different field and weather conditions showing low RMS errors of 1–3 K for wet to dry conditions. Finally, the proposed model is tested under limitations in input data that are associated with remote sensing applications. It is shown that these limitations result in only small increases in the overall error. This approach may be useful for satellite‐based global energy balance applications.
Permanent scatterer InSAR reveals seasonal and long‐term aquifer‐system response to groundwater pumping and artificial recharge
Authors: Bell John W. , Amelung Falk , Ferretti Alessandro , Bianchi Marco , Novali Fabrizio
Published: February 2008

Permanent scatterer InSAR (PSInSAR™) provides a new high‐resolution methodology for detecting and precisely measuring long‐term and seasonal aquifer‐system response to pumping and recharge. In contrast to conventional InSAR, the permanent scatterer methodology utilizes coherent radar phase data from thousands of individual radar reflectors on the ground to develop displacement time series and to produce velocity field maps that depict aquifer‐system response with a high degree of spatial detail. In this study, we present the first results of a prototype study in Las Vegas Valley, Nevada, that demonstrate how this methodology can be utilized in heavily pumped groundwater basins to analyze aquifer‐system response to long‐term and seasonal pumping. We have developed a series of velocity field maps of the valley for the 1992–1996, 1996–2000, and 2003–2005 time periods that show that despite rising water levels associated with an artificial recharge program, long‐term, residual, inelastic aquifer‐system compaction (subsidence) is continuing in several parts of the valley. In other areas, however, long‐term subsidence has been arrested and locally reversed. The seasonal, elastic responses to alternating pumping and recharge cycles were segregated from the long‐term trends and analyzed for spatial and temporal patterns. The results show oscillations in which the maximum seasonal responses are associated with the late stages of the annual artificial recharge cycles, and that similar seasonal subsidence signals are related to summer pumping cycles. The differentiation of the seasonal response through the use of time series data further allows the estimation of elastic and inelastic skeletal storage coefficients, providing a basis for future work that could characterize the storage properties of an aquifer system with a high degree of spatial resolution.
Role of gp130‐mediated signalling pathways in the heart and its impact on potential therapeutic aspects
Authors: Fischer P , Hilfiker‐Kleiner D
Published: February 2008

IL‐6‐type cytokines bind to plasma membrane receptor complexes containing the common signal transducing receptor chain gp130 that is ubiquitously expressed in most tissues including the heart. The two major signalling cascades activated by the gp130 receptor, SHP2/ERK and STAT pathways, have been demonstrated to play important roles in cardiac development, hypertrophy, protection and remodelling in response to physiological and pathophysiological stimuli. Experimental data, both in vivo and in vitro, imply beneficial effects of gp130 signalling on cardiomyocytes in terms of growth and survival. In contrast, it has been reported that elevated serum levels of IL‐6 cytokines and gp130 proteins are strong prognostic markers for morbidity and mortality in patients with heart failure or after myocardial infarction. Moreover, it has been shown that the local gp130 receptor system is altered in failing human hearts. In the present review, we summarize the basic principles of gp130 signalling, which requires simultaneous activation of STAT and ERK pathways under the tight control of positive and negative intracellular signalling modulators to provide a balanced biological outcome. Furthermore, we highlight the key role of the gp130 receptor and its major downstream effectors in the heart in terms of development and regeneration and in response to various physiological and pathophysiological stress situations. Finally, we comment on tissue‐specific diversity and challenges in targeted pharmacological interference with components of the gp130 receptor system.

British Journal of Pharmacology (2008) 153, S414–S427; doi:10.1038/bjp.2008.1; published online 4 February 2008
Gates and filters: unveiling the physiological roles of nicotinic acetylcholine receptors in dopaminergic transmission
Authors: Wonnacott S
Published: February 2008

Neuronal nicotinic acetylcholine receptors (nAChRs) in the brain have been enigmatic players on the cerebral stage. As ligand‐gated ion channels they were expected to mediate fast cholinergic transmission, yet their influence appears to be modulatory. Two reviews in this issue of the BJP consider the relationship between nAChRs and endogenous ACh, with respect to the modulation of dopaminergic signalling. In his review, Maskos posits that in midbrain dopamine neurons, somatodendritic nAChRs activated by cholinergic inputs from the pedunculopontine tegmental nucleus (PPTg) and laterodorsal tegmental nucleus (LDTg) serve as a ‘gate’ that facilitates the switch to burst firing. In the terminal field, Exley and Cragg argue that nAChRs function as a ‘presynaptic filter’ to enhance the contrast between single and repetitive spike firing. Thus somatodendritic and presynaptic nAChRs exert subtle and complementary influences in responding to cholinergic inputs.

British Journal of Pharmacology (2008) 153, S2–S4; doi:10.1038/sj.bjp.0707583; published online 4 February 2008
Analysis of the effects of oestrogen receptor α (ERα)‐ and ERβ‐selective ligands given in combination to ovariectomized rats
Authors: Hertrampf T , Seibel J , Laudenbach U , Fritzemeier K H , Diel P
Published: February 2008

Background and purpose:

Studies with oestrogen receptorα (ERα)‐ and ERβ‐selective compounds have already shown that the effects of 17β‐estradiol (E2) on body weight, movement drive and bone‐protection are mediated via ERα. This study was based on the hypothesis that activation of ERβ may antagonize ERα‐mediated effects and designed to investigate potential effects of ERα/ERβ heterodimers.

Experimental approach:

Ovariectomized (OVX) female Wistar rats were treated with combinations of the ERα‐specific agonist 16α‐LE2 (ALPHA; 1 and 10 μg kg−1 d−1), the ERβ‐specific agonist 8β‐VE2 (BETA; 100 μg kg−1 d−1), the phytoestrogen, genistein (10 mg kg−1 d−1) and with the anti‐oestrogen compound, ICI 182,780 (3 mg kg−1 d−1) for three weeks. The combined effects of the substances on body weight increase, tibial bone mineral density (BMD) and the influence on running wheel activity (RWA) were investigated.

Key results:

OVX‐induced body weight increase was reduced by co‐administration of genistein and BETA. Co‐application of BETA or genistein with ALPHA had no effect on ALPHA‐mediated bone‐protection. The RWA of OVX animals was significantly reduced by treatment with genistein but stimulated by application of ALPHA. The stimulatory effect of ALPHA on RWA could be antagonized by co‐treatment with the pure antioestrogen ICI 182,780 but also by co‐administration of genistein or BETA.

Conclusions and implications:

Our results indicate that activation of ERβ may modulate ERα‐mediated physiological effectsin vivo. The observation that substances with selective affinity for ERβ are able to antagonize distinct physiological functions, like RWA, may be of great relevance to the pharmaceutical use of such drugs.

British Journal of Pharmacology(2008)153, 1432–1437; doi:10.1038/sj.bjp.0707664; published online 4 February 2008
Internalization: what does it tell us about pharmacokinetic and pharmacodynamic properties of an antagonist?
Authors: Mueller A
Published: February 2008

British Journal of Pharmacology (2008) 153, 620; doi:10.1038/sj.bjp.0707671
The A2A‐adenosine receptor: a GPCR with unique features?
Authors: Zezula J , Freissmuth M
Published: February 2008

The A2A‐adenosine receptor is a prototypical Gs‐coupled receptor. However, the A2A‐receptor has several structural and functional characteristics that make it unique. In contrast to the classical model of collision coupling described for the β‐adrenergic receptors, the A2A‐receptor couples to adenylyl cyclase by restricted collision coupling and forms a tight complex with Gs. The mechanistic basis for this is not clear; restricted collision coupling may arise from the interaction of the receptor with additional proteins or due to the fact that G protein‐coupling is confined to specialized membrane microdomains. The A2A‐receptor has a long C‐terminus (of >120 residues), which is for the most part dispensable for coupling to Gs. It was originally viewed as the docking site for kinases and the β‐arrestin family to initiate receptor desensitization and endocytosis. The A2A‐receptor is, however, fairly resistant to agonist‐induced internalization. Recently, the C‐terminus has also been appreciated as a binding site for several additional ‘accessory’ proteins. Established interaction partners include α‐actinin, ARNO, USP4 and translin‐associated protein‐X. In addition, the A2A‐receptor has also been reported to form a heteromeric complex with the D2‐dopamine receptor and the metabotropic glutamate receptor‐5. It is clear that (i) this list cannot be exhaustive and (ii) that all these proteins cannot bind simultaneously to the receptor. There must be rules of engagement, which allow the receptor to elicit different biological responses, which depend on the cellular context and the nature of the concomitant signal(s). Thus, the receptor may function as a coincidence detector and a signal integrator.

British Journal of Pharmacology (2008) 153, S184–S190; doi:10.1038/sj.bjp.0707674; published online 4 February 2008
Molecular cloning and characterization of GhNPR1, a gene implicated in pathogen responses from cotton (Gossypium hirsutum L.)
Authors: Zhang Ying , Wang Xia , Cheng Cheng , Gao Qiuqiang , Liu Jingyun , Guo Xingqi
Published: February 2008

A novel gene, designated as GhNPR1 (Gossypium hirsutum non-expressor of pathogenesis-related genes 1), was isolated from G. hirsutum (cotton) by RT–PCR (reverse transcription–PCR) and RACE (rapid amplification of cDNA ends). The full-length cDNA was 2108 bp long and had an ORF (open reading frame) that putatively encoded a polypeptide of 592 amino acids, with a predicted molecular mass of 66 kDa. Comparison of this protein sequence with that of Arabidopsis thaliana, Brassica juncea and Nicotiana tabacum showed that the amino-acid homology was 52.98, 52.32 and 54.98% respectively. Analysis of the exon–intron structure of the GhNPR1 gene showed that GhNPR1 consisted of four exons and three introns. Southern-blot analysis revealed that the GhNPR1 was a single-copy gene in cotton. Northern-blot analysis indicated that GhNPR1 was constitutively expressed in all tested tissues, including roots, stems and leaves, with the high expression in stems and leaves. In addition, GhNPR1 was also found to be induced by signalling molecules for plant defence responses, such as methyl jasmonate, salicylic acid and ethylene, as well as attack by pathogens, such as Fusarium oxysporum and Xanthomonas campestris. These results suggest that GhNPR1 may play an important role in the response to pathogen infections in cotton plants.
Diagnostics of a He+ beam extracted from a compact magnetic bucket-type ion source
Authors: Sugawara H. , Shinto K. , Tanaka N. , Takeuchi S. , Kikuchi M. , Okamoto A. , Kitajima S. , Sasao M. , Wada M.
Published: February 2008

Performance of a compact He+ ion source was investigated before installing it to the experiment system developed for studying the efficiency of autodetachment neutralization from He− to He0. Dependence of the extracted ion current upon the plasma parameters and that upon the extraction voltage indicated that the source performance was limited by space charge effect. The beam emittance was measured with a multislit system for various operation conditions. The experimentally determined emittance agreed well with the emittance obtained from ion trajectories calculated with input plasma parameters measured by a Langmuir probe. The beam current density of 60mA∕cm2 and the emittance of less than 25πmmmrad are expected to deliver enough current to the downstream of the He− neutralizer system to clarify factors affecting the final He0 intensity.
A control system of a negative hydrogen ion sources by using an EPICS-based proportional-integral-derivative
Authors: Hong In Seok , Song Young Gi , Cho Yong Sub
Published: February 2008

We have developed an EPICS-based control system for a multicusp negative ion source based on a VME IOC software, a sequencer controlling a closed proportional integral (PI) loop, and an interlock. The PI loop was tuned by a step input voltage, and tuning gains of the proportion and integral have been determined. The PI logics, developed by using standard proportional-integral-derivative records, can control the arc current within ±1% of a given set value.
An ion optics study for KSTAR neutral beam injector development
Authors: Kim Jinchoon , Chang D. H. , Chang D. S. , In S. R. , Jeong S. H. , Jin J. T. , Jung K. S. , Kim B. Y. , Kim T. S. , Lee K. W. , Oh B. H. , Seo C. S. , Seo M. S. , Song W. S. , Yoon B. J.
Published: February 2008

Ion optics of three accelerator geometries was studied in terms of an analytic linear optics analysis, a numerical simulation using the IGUN program, an optical multichannel measurement of Doppler-shifted Hα lines, and a water-flow calorimetry on the beam absorbing target. In general, there was a reasonable agreement observed between the four analysis methods and thus the theoretical analyses can be utilized with confidence for design iteration.
Negative ion transport inside collisional presheaths
Authors: Cavenago M.
Published: February 2008

Modeling of negative ion sources proposed for spallation sources or neutral beam injectors must include several ion production mechanisms, in particular, for wall production, the initially backward ion motion must be reversed in the presheath to obtain extraction. An adequate analytic simplification of the full Vlasov-Boltzmann equations to a one space dimension model for the investigation of the transport effects of the presheath voltage is described here. Integrodifferential collision dominated transport equations are written and solved for typical profiles of the presheath voltage. The results for space charge density improve previous estimates. A transverse magnetic field can be included in the formalism to treat electron transport: principles of its solution are summarized and numerical examples are given; plasma quasineutrality is approximately verified.
Non-negative matrix factorization of two-dimensional NMR spectra: Application to complex mixture analysis
Authors: Snyder David A. , Zhang Fengli , Robinette Steven L. , Bruschweiler-Li Lei , Brüschweiler Rafael
Published: February 2008

A central problem in the emerging field of metabolomics is how to identify the compounds comprising a chemical mixture of biological origin. NMR spectroscopy can greatly assist in this identification process, by means of multi-dimensional correlation spectroscopy, particularly total correlation spectroscopy (TOCSY). This Communication demonstrates how non-negative matrix factorization (NMF) provides an efficient means of data reduction and clustering of TOCSY spectra for the identification of unique traces representing the NMR spectra of individual compounds. The method is applied to a metabolic mixture whose compounds could be unambiguously identified by peak matching of NMF components against the BMRB metabolomics database.
Determination of methyl C13–N15 dipolar couplings in peptides and proteins by three-dimensional and four-dimensional magic-angle spinning solid-state NMR spectroscopy
Authors: Helmus Jonathan J. , Nadaud Philippe S. , Höfer Nicole , Jaroniec Christopher P.
Published: February 2008

We describe three- and four-dimensional semiconstant-time transferred echo double resonance (SCT-TEDOR) magic-angle spinning solid-state nuclear magnetic resonance (NMR) experiments for the simultaneous measurement of multiple long-range N15–Cmethyl13 dipolar couplings in uniformly C13, N15-enriched peptides and proteins with high resolution and sensitivity. The methods take advantage of C13 spin topologies characteristic of the side-chain methyl groups in amino acids alanine, isoleucine, leucine, methionine, threonine, and valine to encode up to three distinct frequencies (N15–Cmethyl13 dipolar coupling, N15 chemical shift, and Cmethyl13 chemical shift) within a single SCT evolution period of initial duration ∼1∕JCC1 (where JCC1≈35Hz, is the one-bond Cmethyl13–C13 J-coupling) while concurrently suppressing the modulation of NMR coherences due to C13–C13 and N15–C13 J-couplings and transverse relaxation. The SCT-TEDOR schemes offer several important advantages over previous methods of this type. First, significant (approximately twofold to threefold) gains in experimental sensitivity can be realized for weak N15–Cmethyl13 dipolar couplings (corresponding to structurally interesting, ∼3.5Å or longer, distances) and typical Cmethyl13 transverse relaxation rates. Second, the entire SCT evolution period can be used for Cmethyl13 and/or N15 frequency encoding, leading to increased spectral resolution with minimal additional coherence decay. Third, the experiments are inherently “methyl selective,” which results in simplified NMR spectra and obviates the use of frequency-selective pulses or other spectral filtering techniques. Finally, the N15–C13 cross-peak buildup trajectories are purely dipolar in nature (i.e., not influenced by J-couplings or relaxation), which enables the straightforward extraction of N15–Cmethyl13 distances using an analytical model. The SCT-TEDOR experiments are demonstrated on a uniformly C13, N15-labeled peptide, N-acetyl-valine, and a 56 amino acid protein, B1 immunoglobulin-binding domain of protein G (GB1), where the measured N15–Cmethyl13 dipolar couplings provide site-specific information about side-chain dihedral angles and the packing of protein molecules in the crystal lattice.
Measurement of N15-T1 relaxation rates in a perdeuterated protein by magic angle spinning solid-state nuclear magnetic resonance spectroscopy
Authors: Chevelkov Veniamin , Diehl Anne , Reif Bernd
Published: February 2008

In this paper, we present the measurement of N15-T1 relaxation times in the solid state for a perdeuterated protein for which exchangeable protons are back substituted during recrystallization using a buffer which contains 10% H2O and 90% D2O. We find large variations of the N15 relaxation time, even within the same β sheet. By comparing N15-T1 relaxation times measured for a protonated and a deuterated protein (using the above mentioned approach), we conclude that H1 driven N15,N15 spin diffusion has a significant impact on the absolute N15 relaxation time in protonated proteins. This effect is important for a quantitative analysis of relaxation data in terms of molecular dynamics.
Evaluation and utilization of beam simulation codes for the SNS ion source and low energy beam transport development
Authors: Han B. X. , Welton R. F. , Stockli M. P. , Luciano N. P. , Carmichael J. R.
Published: February 2008

Beam simulation codes PBGUNS, SIMION, and LORENTZ-3D were evaluated by modeling the well-diagnosed SNS base line ion source and low energy beam transport (LEBT) system. Then, an investigation was conducted using these codes to assist our ion source and LEBT development effort which is directed at meeting the SNS operational and also the power-upgrade project goals. A high-efficiency H− extraction system as well as magnetic and electrostatic LEBT configurations capable of transporting up to 100mA is studied using these simulation tools.
Long-pulse arc-discharge plasma source with cold cathode for diagnostic neutral beam injector
Authors: Deichuli P. P. , Ivanov A. A. , Stupishin N. V.
Published: February 2008

Long-pulse cold cathode arc-discharge plasma generators have been successfully used as high-quality hydrogen ion sources for plasma diagnostic neutral beams. One of the main advantages of this type of plasma source is a high proton fraction (80%–90%). However, the lifetime of the plasma source is limited due to intensive electrode’s erosion, especially at the cathode region. An optimized design of the cathode and the nearest electrodes is found which reduces the erosion and allows us to increase the pulse length. The plasma source produces the extracted ion current up to 3A at a low angular divergence, and at the pulse duration up to 2s.