bluuebunny/crossref_metadata_2025 huggingface dataset:
The nature and role of experiential knowledge for environmental conservation
Authors: FAZEY IOAN , FAZEY JOHN A. , SALISBURY JANET G. , LINDENMAYER DAVID B. , DOVERS STEVE
Published: May 2006

Understanding the nature and role of experiential knowledge for environmental conservation is a necessary step towards understanding if it should be used and how it might be applied with other types of knowledge in an evidence-based approach. This paper describes the nature of experiential and expert knowledge. It then discusses the role of experiential knowledge as a complement to scientific knowledge and explains the interplay between experiential knowledge with conservation research and practice using a simple conceptual model of how individuals learn. There are five main conclusions: (1) because experiential knowledge will always play a role in decision-making, enhancing ability to learn from experiences (including research) will have a significant influence on the effectiveness of conservation outcomes; (2) while experiential knowledge is qualitatively very different from quantitative information, both are important and complementary; (3) some experiential knowledge can be expressed quantitatively, but experiential knowledge can be difficult to isolate as single facts or propositions and qualitative methods will therefore often be required to elicit experiential knowledge; (4) because each person's expertise is unique, when using experiential knowledge the extent of a person's experience and its relevance to a particular problem need to be specified; and (5) as with any form of knowledge, there are limitations to that derived from personal experience. Synthesis and communication of research is therefore essential to help prevent erroneous thinking and, where possible, experiential knowledge should be used in conjunction with other types of information to guide conservation actions.
Modelling hospital admissions for lower respiratory tract infections in the elderly in England
Authors: MÜLLER-PEBODY B. , CROWCROFT N. S. , ZAMBON M. C. , EDMUNDS W. J.
Published: May 2006

Despite the importance of lower respiratory-tract infection (LRI) in causing hospitalizations in elderly patients ([ges ]65 years of age) and recent advances in vaccine development, a complete picture of the causative organisms is not available. All hospital discharge diagnoses (ICD-10 code) for LRI in elderly patients in England during 1995–1998 were reviewed. Using known seasonality in potential causative agents of LRI, the contribution of different respiratory pathogens to hospitalizations coded as ‘unspecified LRI’ was estimated by multiple linear regression analysis. Ninety-seven per cent of 551633 LRI-associated diagnoses had no specific organism recorded. From the statistical model the estimated proportions of admissions attributable to different pathogens were applied to calculate estimated hospitalization rates: 93·9 hospitalizations/10000 population aged [ges ]65 years due to S. pneumoniae, 22·9 to influenza virus, 22·3 to H. influenzae, 17·0 to whooping cough, and 12·8 to respiratory syncytial virus. There is enormous potential to improve health using existing vaccines and those under development.
The doleful airs of Euripides: The origins of opera and the spirit of tragedy reconsidered
Authors: HOXBY BLAIR
Published: May 2006

Scholarly consensus denies a real connection between ancient tragedy and early opera because music historians have measured early operas against an idealised conception of Attic tragedy. However, the pioneers of opera were seeking to revive a Euripidean style of musical tragedy as it was performed in the ‘decadent’ theatres of the Hellenistic era. Euripides's tragedies established conventional relationships between musical expression and the representation of the passions. Baroque opera is seen as a strongly complex reading of a set of Euripidean tragedies that enjoyed favour in the Hellenistic era but fell from critical grace in the nineteenth century. These plays hold the key to opera's tragic pretensions; the esteem they long enjoyed should prompt us to reconsider the spirit of tragedy and the nature of catharsis.
‘Veluti in speculum’: The twilight of the castrato
Authors: DAVIES
Published: May 2006

The final performances of castrato Giovanni Battista Velluti in London in the late 1820s constitute a particularly rich vantage point from which to explore why the castrato was eventually forced from the operatic stage. What does this historical moment have to say about shifts in vocal style and audience expectations? Why did the question of castration become so loaded under ‘Romantic’ conditions? This article constructs a speculative theoretical framework by bringing together recent insights in the history of vocal science, histories of gender and subjectivity, the history of listening and opera studies. Velluti's hostile reception in the London press is surveyed in detail, alongside a historically informed examination of his vocal manner. Evidence suggests that the castrato quickly became an unthinkable figure, falling from grace in the wake of embodied conceptions of vocality and ‘natural’ expression, newly dominant ideas that projected him beyond prevailing notions of human nature.
The witches and the witch: Verdi's Macbeth
Authors: ALBRIGHT DANIEL
Published: May 2006

The witches in Shakespeare’s Macbeth equivocate between the demons of random malevolence and ordinary (if exceptionally nasty) old women; and both King James I, whose book on witchcraft may have influenced Shakespeare, and A. W. Schlegel, whose essay on Macbeth certainly influenced Verdi, also stress this ambiguity. In his treatment of Lady Macbeth, Verdi uses certain musical patterns associated with the witches; and like the witches, who sound sometimes tame and frivolous, sometimes like incarnations of supernatural evil, Lady Macbeth hovers insecurely between roles: she is a hybrid of ambitious wife and agent of hell.
Relevance of the measurement of the concentration of lactate in the serum subsequent to the Fontan procedure in small children
Authors: Hamamoto Masaki , Uemura Hideki , Imanaka Hideaki , Yagihara Toshikatsu
Published: May 2006

Background:To determine the clinical relevance of change in the level of lactate in the serum as a meanings of establishing the efficacy of the circulation immediately after the Fontan procedure in small children.Methods:We measured the concentration of lactate in the serum consecutively in 30 patients undergoing the Fontan procedure, without fenestration, under the age of 2 years. Of these, we did not use cardiopulmonary bypass in 13.Results:Concentrations gradually increased during the first several hours after establishment of the Fontan circulation, and then eventually decreased, reaching the normal range within 48 hours, with specific values of 0.9 plus or minus 0.3 pre-operatively, 2.3 plus or minus 1.1 immediately after creation of the Fontan circulation, 4.0 plus or minus 2.4 at 6 hours, 1.6 plus or minus 0.6 at 24 hours, and finally 1.3 plus or minus 0.4 millimoles per litre at 48 hours. This trend was irrespective of use or no use of cardiopulmonary bypass. The higher initial level in the intensive care unit was related to higher systemic venous pressure, higher transpulmonary pressure gradient, higher maximal level of alanine transaminase and blood urea nitrogen, and longer duration of peritoneal drainage, the latter as a monitor of sequestration of fluid rather than peritoneal dialysis. In patients with initial levels greater than 3.0 millimoles per litre, there was extended duration of endotracheal intubation.Conclusions:Postoperative changes in the levels of lactate in the serum subsequent to creation of the Fontan procedure were peculiar, not necessarily correlated with the cardiac output, but relevant to the clinical course.
A comparison of magnetic resonance angiography with conventional angiography in the diagnosis of tetralogy of Fallot
Authors: Moll Bernardes Renata Junqueira , Marchiori Edson , Bernardes Paulo Manuel de Barros , Monzo Gonzaga Maria Beatriz Albano , Simões Luiz Carlos
Published: May 2006

Aims: Our purpose was to assess the value of magnetic resonance angiography as a non-invasive alternative to catheterization in the evaluation of patients with tetralogy of Fallot, including those with pulmonary atresia. Methods and results: We evaluated prospectively, using magnetic resonance angiography, 30 patients, aged from 1 to 18 years, 15 with tetralogy of Fallot and pulmonary stenosis, and 15 with pulmonary atresia. The studies obtained using magnetic resonance provided adequate visualization of the aorta, and provided excellent imaging of the pulmonary trunk and its right and left branches. Compared with catheterization, magnetic resonance had 100 percent sensitivity, specificity and accuracy for defining the presence or absence of the pulmonary arteries. Magnetic resonance also had 93.9 percent sensitivity, 98.2 percent specificity, and 96.7 percent accuracy for detection of stenosis or hypoplasia of the pulmonary arteries. We detected 25 major aortopulmonary collateral arteries with magnetic resonance, but only 22 with conventional angiography. There was complete agreement between the two methods in detecting patency of the arterial duct in 6 patients, and of Blalock-Taussig shunts in 12 patients. Conclusion: Magnetic resonance angiography is a useful tool in the evaluation of patients with tetralogy of Fallot. It can be considered a non-invasive alternative to cardiac catheterization in the evaluation of the pulmonary vascular anatomy.
Prioritization of congenital cardiac surgical patients using fuzzy reasoning – a solution to the problem of the waiting list?
Authors: Holzer Ralf , Ladusans Ed , Kitchiner Denise , Peart Ian , Gladman Gordon , Miles Gail
Published: May 2006

Surgical waiting lists are of high importance in countries, where the national health system is unable to deliver surgical services at a rate that would allow patients to avoid unnecessary periods of waiting. Prioritization of these lists, however, is frequently arbitrary and inconsistent.

The objective of our research was to analyze the medical decision-making process when prioritizing patients with congenital cardiac malformations for cardiac surgical procedures, identifying an appropriate representation of knowledge, and transferring this knowledge onto the design and implementation of an expert system (“PrioHeart”).

The medical decision-making process was stratified into three stages. The first was to analyze the details of the procedure and patient to define important impact factors on clinical priority, such as the risk of adverse events. The second step was to evaluate these impact factors to define an appropriate “timing category” within which a procedure should be performed. The third, and final, step was to re-evaluate the characteristics of individual patients to differentiate between those in the same timing category.

We implemented this decision-making process using a rule-based production system with support for fuzzy sets, using the FuzzyCLIPS inference engine and expert system shell as a suitable development environment for the knowledge base.

The “PrioHeart” expert system was developed to give paediatric cardiologists a tool to allow and facilitate the prioritization of patients on the cardiosurgical waiting list. Evaluation of “PrioHeart” on limited sets of patients documented appropriate results of prioritization, with a significant correlation between the prioritization made using “PrioHeart” and those results obtained by the individual consultant specialist.

We conclude that our study has demonstrated the feasibility of using an expert system approach with a fuzzy, rule-based production system to implement the prioritization of cardiac surgical patients. The approach may potentially be transferable to other medical subspecialities.
The relationship between scimitar syndrome, so-called scimitar variant, meandering right pulmonary vein, horseshoe lung and pulmonary arterial sling
Authors: Yoo Shi-Joon , Al-Otay Abdulmajeed , Babyn Paul
Published: May 2006

We report a case in which a meandering right pulmonary vein connecting to the left atrium is associated with hypoplasia of the right lung, horseshoe lung, abnormal pulmonary lobation, and abnormal branching of the pulmonary arteries. We discuss its relationship to the so-called scimitar variant, and to the scimitar syndrome itself.
A familial variant of the Scimitar syndrome with a meandering pulmonary vein
Authors: Al-Naami Ghassan H. , Abu-Sulaiman Riyadh M.
Published: May 2006

We report a rare variant of the Scimitar syndrome, in which the right lower pulmonary vein takes a meandering course before finally connecting in normal fashion to the left atrium. The pulmonary parenchymal segment drained by the tortuous vein is supplied by a systemic collateral artery, which was coiled via a catheter. We also closed the intracardiac defects by surgery. The elder brother of the patient had classical Scimitar syndrome.
An unusual form of anomalous systemic arterial supply to the left lung
Authors: Fernandez-Martorell Patricio , Yoo Shi-Joon , Benson Leland N.
Published: May 2006

We report an unusual case in which the peripheral part of the otherwise normal left lung was supplied by major systemic arteries arising from the left subclavian, internal mammary and coeliac arteries. Unlike most cases with systemic arterial supply to a normal or sequestered lung, where the systemic arterial branches get access to the lung through the pulmonary hilum or inferior pulmonary ligament, in our patient the systemic arterial branches entered the lung through the transpleural routes.
Assessment of a three dimensional model for atmospheric radiative transfer over heterogeneous land cover
Authors: McComiskey A. , Ricchiazzi P. , Gautier C. , Lubin D.
Published: May 2006

A three‐dimensional (3D) atmospheric radiative transfer model that explicitly represents surface albedo heterogeneity is tested against a one‐dimensional model and surface irradiance observations in a polar region where land cover heterogeneity is high. For observations located near high latitude coastlines, the contrast between the highly absorbing ocean and reflective snow surface creates spatial heterogeneity, or a 3D effect, around the observation site. The resulting effect on radiation at the sensor should be taken into account when using a solar radiative transfer model to interpret measurements. This assessment shows that better closure is obtained with a three‐dimensional model (≤5%) versus a plane‐parallel model (≤7%). The importance of the surface 3D effect increases with aerosol or cloud optical depth and with surface albedo contrast. The model used here can be implemented at any surface site given the surrounding land cover properties.
Toward a better quantitative understanding of polar stratospheric ozone loss
Authors: Frieler K. , Rex M. , Salawitch R. J. , Canty T. , Streibel M. , Stimpfle R. M. , Pfeilsticker K. , Dorf M. , Weisenstein D. K. , Godin‐Beekmann S.
Published: May 2006

Previous studies have shown that observed large O3 loss rates in cold Arctic Januaries cannot be explained with current understanding of the loss processes, recommended reaction kinetics, and standard assumptions about total stratospheric chlorine and bromine. Studies based on data collected during recent field campaigns suggest faster rates of photolysis and thermal decomposition of ClOOCl and higher stratospheric bromine concentrations than previously assumed. We show that a model accounting for these kinetic changes and higher levels of BrO can largely resolve the January Arctic O3 loss problem and closely reproduces observed Arctic O3 loss while being consistent with observed levels of ClO and ClOOCl. The model also suggests that bromine catalysed O3 loss is more important relative to chlorine catalysed loss than previously thought.
Localized compaction in rocks: Eshelby's inclusion and the Spring Network Model
Authors: Katsman R. , Aharonov E. , Scher H.
Published: May 2006

Porous rocks, subjected to compressive stress, often undergo mechanical compaction via grain crushing and rearrangement, and chemical compaction via pressure solution. The compaction leads to irreversible volume reduction that spontaneously localizes into elongated features under some conditions. This work presents an analytical solution for the stress around a 2D compaction band (CB), using the “transformation problem” introduced by Eshelby (1957). The analytical solution is shown to agree with results from a new version of a Spring Network Model for simulating mechanical and chemical compaction. The similarity of the stress fields around CBs and edge‐dislocations is shown and is such that one may describe CBs as anti‐dislocations.
Characteristics and implications of Doppler spectra of E region quasi‐periodic echoes observed by the multibeam middle and upper atmosphere radar
Authors: Ogawa Tadahiko , Otsuka Yuichi , Yamamoto Mamoru
Published: May 2006

We present multibeam middle and upper atmosphere (MU) radar observations of quasi‐periodic (QP) echoes from 3.2‐m field‐aligned irregularities associated with plasma patches in the nighttime midlatitude sporadic E (Es) layers over Shigaraki, Japan, to give a cohesive view of the QP echo characteristics. Echo regions with zonal scales less than 50 km moved westward at altitudes near 105 km with trace velocities of 110–120 m s−1 and crossed the radar beams successively. Doppler spectra of the echoes changed in time, range, and azimuth and exhibited mostly type 2 echoes with Doppler velocities between −200 and +200 m s−1 and occasionally type 1 echoes due to the two‐stream instability (“the first type 1 echo detection by the MU radar”). We find that the spectra near the middle of the drifting echo region have two type 2 peaks, one at positive Doppler velocity (motion away from the radar) and the other at negative one (motion toward the radar) and that the spectra in the west and east parts of the echo region have single type 2 peak at positive and negative Doppler velocities, respectively. Interestingly, the type 1 echoes lasting for about 4 min on a fixed beam were located near the middle of the echo region. Their Doppler shifts between 250 and 320 m s−1 are very consistent with those from previous type 1 echo observations at other midlatitude locations. Occasionally, type 1 and type 2 echoes coexisted in the same range gates. On the basis of recent observations, theories, and simulations related to QP echoes, we propose a simple model of an Es plasma patch to explain the observations. In the model, polarization electric fields with opposite polarity inside and outside the patch, elongated along the NW‐SE direction, play a predominant role in exciting type 1 and type 2 echoes, and cause a variety of Doppler spectra.
Recovering lateral variations in lithospheric strength from bedrock motion data using a coupled ice sheet‐lithosphere model
Authors: van den Berg J. , van de Wal R. S. W. , Oerlemans J.
Published: May 2006

A vertically integrated two‐dimensional ice flow model was coupled to an elastic lithosphere‐Earth model to study the effects of lateral variations in lithospheric strength on local bedrock adjustment. We used a synthetic bedrock profile and a synthetic climate to model a characteristic ice sheet through an ice age cycle. Realistic differences in lithospheric strength altered the local bedrock adjustment up to 100 m, the ice extent by tens of kilometers, and the ice volume by several percent. Hence, when modeling ice sheets, it is essential to include information on lithospheric structure. In addition, we used the coupled ice flow–lithosphere model to construct synthetic bedrock motion time series to assess their potential in resolving lithospheric structure. Inverse experiments showed that the model can resolve lateral variations in lithospheric strength from these bedrock motion time series, provided that we have data from both sides of a lateral transition in lithospheric strength. The inversion that solved for a lateral transition was able to find a solution that was consistent with all data, even if they were noisy. In the presence of lateral variations in lithospheric strength, there was no solution to the inverse problem for which all data were modeled correctly by a uniform lithospheric model. The synthetic data showed no significant sensitivity to the location of the transition. Hence we require information from independent sources, such as seismology or gravity, about the locations of transitions in lithospheric strength.
Zooplankton biomass estimated from digitalized images in Antarctic waters: A calibration exercise
Authors: Hernández‐León Santiago , Montero Irene
Published: May 2006

The direct measurement of zooplankton biomass following the different analytical procedures normally requires the destruction of the samples. The use of conversion factors to estimate biomass from nondestructive methods is still a challenge. The widespread use of image analyzers and optical counters in biological oceanography provides a useful tool to measure the abundance and size spectrum of zooplanktonic organisms in real or quasi‐real time. Both methodologies measure the equivalent spherical diameter and/or the body area of organisms. In order to estimate biomass from the highly valuable information generated by the size spectrum of the sample, we measured the relationship between individual body area and individual biomass of the most common species and groups of zooplankton in Antarctic waters. The slope of the regression for each different species and groups of taxa was not significantly different from that obtained by pooling all taxa, thus providing a general relationship for the entire size spectrum of zooplankton. The biomass estimated from the body area spectrum of samples obtained around the Antarctic Peninsula agreed with other measurements of biomass in the region. The proposed conversion factor could provide for rapid estimates of biomass of net‐collected zooplankton from imaging devices or optical plankton counters.
Variability of ocean heat uptake: Reconciling observations and models
Authors: AchutaRao K. M. , Santer B. D. , Gleckler P. J. , Taylor K. E. , Pierce D. W. , Barnett T. P. , Wigley T. M. L.
Published: May 2006

This study examines the temporal variability of ocean heat uptake in observations and in climate models. Previous work suggests that coupled Atmosphere‐Ocean General Circulation Models (A‐OGCMs) may have underestimated the observed natural variability of ocean heat content, particularly on decadal and longer timescales. To address this issue, we rely on observed estimates of heat content from the 2004 World Ocean Atlas (available at http://www.nodc.noaa.gov/OC5/indprod.html, hereinafter referred to as WOA‐2004) compiled by Levitus et al., 2005. Given information about the distribution of observations in WOA‐2004, we evaluate the effects of sparse observational coverage and the infilling that Levitus et al. use to produce the spatially complete temperature fields required to compute heat content variations. We first show that in ocean basins with limited observational coverage, there are important differences between ocean temperature variability estimated from observed and infilled portions of the basin. We then employ data from control simulations performed with eight different A‐OGCMs as a test bed for studying the effects of sparse, space‐varying and time‐varying observational coverage. Subsampling model data with actual observational coverage has a large impact on the inferred temperature variability in the top 300 and 3000 m of the ocean. This arises from changes in both sampling depth and in the geographical areas sampled. Our results illustrate that subsampling model data at the locations of available observations increases the variability, reducing the discrepancy between models and observations.
Are the Earth and the Moon compositionally alike? Inferences on lunar composition and implications for lunar origin and evolution from geophysical modeling
Authors: Khan A. , Maclennan J. , Taylor S. R. , Connolly J. A. D.
Published: May 2006

The main objective of the present study is to discuss in detail the results obtained from an inversion of the Apollo lunar seismic data set, lunar mass, and moment of inertia. We inverted directly for lunar chemical composition and temperature using the model system CaO‐FeO‐MgO‐Al2O3‐SiO2. Using Gibbs free energy minimization, stable mineral phases at the temperatures and pressures of interest, their modes and physical properties are calculated. We determine the compositional range of the oxide elements, thermal state, Mg#, mineralogy and physical structure of the lunar interior, as well as constraining core size and density. The results indicate a lunar mantle mineralogy that is dominated by olivine and orthopyroxene (−80 vol%), with the remainder being composed of clinopyroxene and an aluminous phase (plagioclase, spinel, and garnet present in the depth ranges 0–150 km, 150–200 km, and >200 km, respectively). This model is broadly consistent with constraints on mantle mineralogy derived from the experimental and observational study of the phase relationships and trace element compositions of lunar mare basalts and picritic glasses. In particular, by melting a typical model mantle composition using the pMELTS algorithm, we found that a range of batch melts generated from these models have features in common with low Ti mare basalts and picritic glasses. Our results also indicate a bulk lunar composition and Mg# different to that of the Earth's upper mantle, represented by the pyrolite composition. This difference is reflected in a lower bulk lunar Mg# (−0.83). Results also indicate a small iron‐like core with a radius around 340 km.
Sediment and particulate carbon removal by pipe erosion increase over time in blanket peatlands as a consequence of land drainage
Authors: Holden Joseph
Published: May 2006

Land drainage is common in peatlands. Artificially drained blanket peat catchments have been shown to have a significantly greater soil pipe density than intact catchments. This paper investigates the role of surface land drains in the enhancement of soil piping in blanket peats. The density of piping was found to significantly increase in a linear fashion with the age of the drainage. Thirty‐five years after drains were cut, slopes would be expected to have twice the density of soil piping than would an undrained blanket peat catchment. The rate of pipe erosion increases exponentially over time, so that particulate carbon loss from subsurface pipes is greatest where drains are oldest.
Microstructural and phase configurational effects determining water content: Dielectric relationships of aggregated porous media
Authors: Blonquist J. M. , Jones S. B. , Lebron I. , Robinson D. A.
Published: May 2006

Many porous media in which we determine water content are aggregated and characterized by a dual‐porosity pore network, composed of interaggregate pores and intra‐aggregate pores. This paper reports sample‐scale permittivity measurements made in four stable aggregate media with dual porosity. Results indicate two distinct dielectric responses depending on whether the aggregates are surrounded by water or air. We relate transitions in the permittivity response to the water retention characteristic (WRC), showing that after the interaggregate pores have drained, the slope of the water content–permittivity relationship is significantly reduced (permittivity values ranging from 5 to 7). The hydraulic critical water content (θhc) is defined as the point where all the interaggregate pores are air filled and all the intra‐aggregate pores are water saturated and is determined from the WRC. The dielectric critical water content (θdc) is defined as the point where a slope change in the measured water content–permittivity relationship occurs. A two‐step model is presented and designed to capture the physical characteristics of the permittivity response to drainage. Measurements of θhc and θdc reveal a separation in these two values. The difference is considered to be a function of the connectivity of the intra‐aggregate pore network. A connectivity ratio is defined as 1‐(θdc/θhc), where values close to 0 indicate low connectivity between the intra‐aggregate pores and values tending to 1 indicate a high level of connectivity. Results from this work indicate that the reduced permittivity response measured in the water content–permittivity relationship is due to microstructure and phase configuration and not to “bound” water.
Stability and equation of state of the post‐perovskite phase in MgGeO3 to 2 Mbar
Authors: Kubo Atsushi , Kiefer Boris , Shen Guoyin , Prakapenka Vitali B. , Cava Robert J. , Duffy Thomas S.
Published: May 2006

The stability and equation of state of the post‐perovskite phase in MgGeO3 were investigated to 2 Mbar by in situ x‐ray diffraction experiments using the laser‐heated diamond cell as well as by theoretical calculations using density functional theory. The stability of the phase was demonstrated at 92‐201 GPa during laser heating. By using the Birch‐Murnaghan equation of state, we obtained a zero‐pressure volume (V0) of 179.2 ± 0.7 Å3, bulk modulus (K0) of 207 ± 5 GPa with a pressure derivative (K′0) of 4.4 from experiments at room temperatures, and V0 = 178.02 Å3, K0 = 201.9 GPa, K′0 = 4.34 from theoretical calculations at 0 K. The relative axial compressibilities of the silicate and germanate post‐perovskite phases are similar although MgSiO3 is more anisotropic than MgGeO3.
Evidence of significant large‐scale impacts of boreal fires on ozone levels in the midlatitude Northern Hemisphere free troposphere
Authors: Lapina K. , Honrath R. E. , Owen R. C. , Val Martín M. , Pfister G.
Published: May 2006

Summertime observations of O3 and CO made at the PICO‐NARE station during 2001, 2003, and 2004 are used to assess the impact of boreal forest fires on the distribution of O3 mixing ratios in the midlatitude Northern Hemisphere (NH) lower free troposphere (FT). Backward trajectories were used to select measurements impacted by outflow from high‐latitude regions. Measurements during these periods were segregated into two subsets: those obtained during periods with and without apparent significant upwind fire emissions. Periods affected by fire emissions were identified based on enhanced CO levels confirmed by global simulations of fire emissions transport. During fire‐impacted periods, O3 was shifted toward higher mixing ratios, with medians significantly higher than in periods without detectable upwind fire impacts. This implies a significant impact of boreal wildfires on midlatitude lower FT background O3 during summer. Predicted future increases in boreal wildfires may therefore affect summertime O3 levels over large regions.
Atmospheric electric fields at the Kennedy Space Center, 1997–2005: No evidence for effects of global warming or modulation by galactic cosmic rays
Authors: Harrison Halstead
Published: May 2006

Near surface, atmospheric voltage gradients [Ez] measured at 31 sites of the Kennedy Space Center [KSC], between Aug. 1997 and Dec. 2005, averaged 162.5 ± 3.5 V/m, positive upward, with a standard deviation of 21.4 V/m and an apparent trend of +0.40 ± 1.04 %/yr. That is, no significant positive trend, predicted to be a consequence of global warming, yet rises above the noise. The correlation of Ez with a monthly index of galactic cosmic rays at Haleakala, Hawaii, was −0.07 ± 0.18, for periods between 2 and 25 months. That is, no significant short‐period effect of solar‐magnetically modulated cosmic‐ray flux on Ez was observed at KSC, during this epoch.
Regulated intramembrane proteolysis of amyloid precursor protein and regulation of expression of putative target genes
Authors: Hébert Sébastien S , Serneels Lutgarde , Tolia Alexandra , Craessaerts Katleen , Derks Carmen , Filippov Mikhail A , Müller Ulrike , De Strooper Bart
Published: May 2006

γ‐Secretase‐dependent regulated intramembrane proteolysis of amyloid precursor protein (APP) releases the APP intracellular domain (AICD). The question of whether this domain, like the Notch intracellular domain, is involved in nuclear signalling is highly controversial. Although some reports suggest that AICD regulates the expression of KAI1, glycogen synthase kinase‐3β, Neprilysin and APP, we found no consistent effects of γ‐secretase inhibitors or of genetic deficiencies in the γ‐secretase complex or the APP family on the expression levels of these genes in cells and tissues. Finally, we demonstrate that Fe65, an important AICD‐binding protein, transactivates a wide variety of different promoters, including the viral simian virus 40 promoter, independent of AICD coexpression. Overall, the four currently proposed target genes are at best indirectly and weakly influenced by APP processing. Therefore, inhibition of APP processing to decrease Aβ generation in Alzheimer's disease will not interfere significantly with the function of these genes.
The physics of edge resonant magnetic perturbations in hot tokamak plasmas
Authors: Evans T. E. , Burrell K. H. , Fenstermacher M. E. , Moyer R. A. , Osborne T. H. , Schaffer M. J. , West W. P. , Yan L. W. , Boedo J. A. , Doyle E. J. , Jackson G. L. , Joseph I. , Lasnier C. J. , Leonard A. W. , Rhodes T. L. , Thomas P. R. , Watkins J. G. , Zeng L.
Published: May 2006

Small edge resonant magnetic perturbations are used to control the pedestal transport and stability in low electron collisionality (νe*), ITER [ITER Physics Basis Editors et al., Nucl. Fusion 39, 2137 (1999)] relevant, poloidally diverted plasmas. The applied perturbations reduce the height of the density pedestal and increase its width while increasing the height of the electron pedestal temperature and its gradient. The effect of the perturbations on the pedestal gradients is controlled by the current in the perturbation coil, the poloidal mode spectrum of the coil, the neutral beam heating power, and the divertor deuterium fueling rate. Large pedestal instabilities, referred to as edge localized modes (ELMs), are completely eliminated with radial magnetic perturbations (δbr(m∕n)) at the q=m∕n=11∕3 surface exceeding δbr(11∕3)Bϕ−1=2.6×10−4, where Bϕ is the toroidal magnetic field on axis. The resulting ELM-free H-mode plasmas have stationary densities and radiated power, are maintained in DIII-D for up to 2550ms (17 energy confinement times), and are limited only by hardware constraints. It is found that changes caused by the magnetic perturbations in the pedestal profiles cannot be explained by a straightforward application of stochastic quasilinear diffusion theory due to the complex nature of the transport physics involved when boundary layer field lines connect regions of hot plasma directly to material surfaces.
Non-Gaussian energy landscape of a simple model for strong network-forming liquids: Accurate evaluation of the configurational entropy
Authors: Moreno A. J. , Saika-Voivod I. , Zaccarelli E. , La Nave E. , Buldyrev S. V. , Tartaglia P. , Sciortino F.
Published: May 2006

We present a numerical study of the statistical properties of the potential energy landscape of a simple model for strong network-forming liquids. The model is a system of spherical particles interacting through a square-well potential, with an additional constraint that limits the maximum number of bonds Nmax per particle. Extensive simulations have been carried out as a function of temperature, packing fraction, and Nmax. The dynamics of this model are characterized by Arrhenius temperature dependence of the transport coefficients and by nearly exponential relaxation of dynamic correlators, i.e., features defining strong glass-forming liquids. This model has two important features: (i) Landscape basins can be associated with bonding patterns. (ii) The configurational volume of the basin can be evaluated in a formally exact way, and numerically with an arbitrary precision. These features allow us to evaluate the number of different topologies the bonding pattern can adopt. We find that the number of fully bonded configurations, i.e., configurations in which all particles are bonded to Nmax neighbors, is extensive, suggesting that the configurational entropy of the low temperature fluid is finite. We also evaluate the energy dependence of the configurational entropy close to the fully bonded state and show that it follows a logarithmic functional form, different from the quadratic dependence characterizing fragile liquids. We suggest that the presence of a discrete energy scale, provided by the particle bonds, and the intrinsic degeneracy of fully bonded disordered networks differentiates strong from fragile behavior.
Effect of plasma shaping on performance in the National Spherical Torus Experiment
Authors: Gates D. A. , Maingi R. , Menard J. , Kaye S. , Sabbagh S. A. , Taylor G. , Wilson J. R. , Bell M. G. , Bell R. E. , Bernabei S. , Bialek J. , Biewer T. , Blanchard W. , Boedo J. , Bush C. , Carter M. D. , Choe W. , Crocker N. , Darrow D. S. , Davis W. , Delgado-Aparicio L. , Diem S. , Ferron J. , Field A. , Foley J. , Fredrickson E. D. , Harvey R. , Hatcher R. E. , Heidbrink W. , Hill K. , Hosea J. C. , Jarboe T. R. , Johnson D. W. , Kaita R. , Kessel C. , Kubota S. , Kugel H. W. , Lawson J. , LeBlanc B. P. , Lee K. C. , Levinton F. , Manickam J. , Maqueda R. , Marsala R. , Mastrovito D. , Mau T. K. , Medley S. S. , Meyer H. , Mikkelsen D. R. , Mueller D. , Munsat T. , Nelson B. A. , Neumeyer C. , Nishino N. , Ono M. , Park H. , Park W. , Paul S. , Peebles W. , Peng M. , Phillips C. , Pigarov A. , Pinsker R. , Ram A. , Ramakrishnan S. , Raman R. , Rasmussen D. , Redi M. , Rensink M. , Rewoldt G. , Robinson J. , Roney P. , Roquemore L. , Ruskov E. , Ryan P. , Schneider H. , Skinner C. H. , Smith D. R. , Sontag A. , Soukhanovskii V. , Stevenson T. , Stotler D. , Stratton B. , Stutman D. , Swain D. , Synakowski E. , Takase Y. , Tritz K. , Halle A. von , Wade M. , White R. , Wilgen J. , Williams M. , Zhu W. , Zweben S. J. , Akers R. , Beiersdorfer P. , Betti R. , Bigelow T.
Published: May 2006

The National Spherical Torus Experiment (NSTX) has explored the effects of shaping on plasma performance as determined by many diverse topics including the stability of global magnetohydrodynamic (MHD) modes (e.g., ideal external kinks and resistive wall modes), edge localized modes (ELMs), bootstrap current drive, divertor flux expansion, and heat transport. Improved shaping capability has been crucial to achieving βt∼40%. Precise plasma shape control has been achieved on NSTX using real-time equilibrium reconstruction. NSTX has simultaneously achieved elongation κ∼2.8 and triangularity δ∼0.8. Ideal MHD theory predicts increased stability at high values of shaping factor S≡q95Ip∕(aBt), which has been observed at large values of the S∼37[MA∕(m∙T)] on NSTX. The behavior of ELMs is observed to depend on plasma shape. A description of the ELM regimes attained as shape is varied will be presented. Increased shaping is predicted to increase the bootstrap fraction at fixed Ip. The achievement of strong shaping has enabled operation with 1s pulses with Ip=1MA, and for 1.6s for Ip=700kA. Analysis of the noninductive current fraction as well as empirical analysis of the achievable plasma pulse length as elongation is varied will be presented. Data are presented showing a reduction in peak divertor heat load due to increasing in flux expansion.
Simulation of monoenergetic electron generation via laser wakefield accelerators for 5–25TW lasers
Authors: Tsung F. S. , Lu W. , Tzoufras M. , Mori W. B. , Joshi C. , Vieira J. M. , Silva L. O. , Fonseca R. A.
Published: May 2006

In 2004, using a 3D particle-in-cell (PIC) model [F. S. Tsung et al., Phys. Rev. Lett. 93, 185004 (2004)], it was predicted that a 16.5TW, 50fs laser propagating through nearly 0.5cm of 3×1018cm−3 preformed plasma channel would generate a monoenergetic bunch of electrons with a central energy of 240MeV after 0.5cm of propagation. In addition, electrons out to 840MeV were seen if the laser propagated through 0.8cm of the same plasma. The simulations showed that self-injection occurs after the laser intensity increases due to a combination of photon deceleration, group velocity dispersion, and self-focusing. The monoenergetic beam is produced because the injection process is clamped by beam loading and the rotation in phase space that results as the beam dephases. Nearly simultaneously [S. P. D. Mangles et al., Nature 431, 535 (2004); C. G. R. Geddes et al., ibid. 431, 538 (2004); J. Faure et al., ibid. 431, 541 (2004)] three experimental groups from around the world reported the generation of near nano-Coulomb of low emittance, monoenergetic electron beams using similar laser powers and pulse lengths as those reported in our simulations. Each of these experiments is modeled using the same 3D PIC code OSIRIS. The simulations indicate that although these experiments use a range of plasma parameters, density profiles, laser powers, and spot sizes; there are some commonalities to the mechanism for the generation of monoenergetic beams. Comments are given on how the energy and beam quality can be improved in the future.
Effects of electric fields on proton transport through water chains
Authors: Hassan Sergio A. , Hummer Gerhard , Lee Yong-Sok
Published: May 2006

Molecular dynamics simulations on quantum energy surfaces are carried out to study the effects of perturbing electric fields on proton transport (PT) in protonated water chains. As an idealized model of a hydrophobic cavity in the interior of a protein the water molecules are confined into a carbon nanotube (CNT). The water chain connects a hydrated hydronium ion (H3O+) at one end of the CNT and an imidazole molecule at the other end. Without perturbing electric fields PT from the hydronium proton donor to the imidazole acceptor occurs on a picosecond time scale. External perturbations to PT are created by electric fields of varying intensities, normal to the CNT axis, generated by a neutral pair of charges on the nanotube wall. For fields above ∼0.5V∕Å, the hydronium ion is effectively trapped at the CNT center, and PT blocked. Fields of comparable strength are generated inside proteins by nearby polar/charged amino acids. At lower fields the system displays a rich dynamic behavior, where the excess charge shuttles back and forth along the water chain before reaching the acceptor group on the picosecond time scale. The effects of the perturbing field on the proton movement are analyzed in terms of structural and dynamic properties of the water chain. The implications of these observations on PT in biomolecular systems and its control by external perturbing fields are discussed.
Proton transfer in imidazole-based molecular crystals
Authors: Iannuzzi Marcella
Published: May 2006

Heterocycles’ aggregates show rather good proton conductivity. In particular, condensed structures formed by imidazole rings that are held together by polymeric chains have attracted some interest as possible candidate materials for fuel cell membranes. However, the details of the proton diffusion process could not be resolved by means of experimental measurements because of the fast rearrangement of the structure after each proton exchange. In this work, we report in detail the results of ab initio molecular dynamics calculations, which were briefly presented in a previous Letter [M. Iannuzzi and M. Parrinello, Phys. Rev. Lett. 93, 025901 (2004)]. The conformational changes associated with the diffusion of protons in model crystalline structures containing chains of imidazole rings are described in the framework of an atomistic approach. In particular, the bonding pattern characterizing the structure of imidazole-2-ethylene-oxide doped by an excess proton is also studied through the calculation of the H1 NMR chemical shifts. The unresolved resonances appearing in the experimental spectra could be associated with specific structural features, in connection with the fluctuating hydrogen bonding. The analysis of the distortions that induce or are induced by the mobility of the protons offers some new hints for the engineering of new proton conducting materials.
Adsorption of supercritical CO2 in aerogels as studied by small-angle neutron scattering and neutron transmission techniques
Authors: Melnichenko Y. B. , Wignall G. D. , Cole D. R. , Frielinghaus H.
Published: May 2006

Small-angle neutron scattering (SANS) has been used to study the adsorption behavior of supercritical carbon dioxide (CO2) in porous Vycor glass and silica aerogels. Measurements were performed along two isotherms (T=35 and 80°C) as a function of pressure (P) ranging from atmospheric up to 25MPa, which corresponds to the bulk fluid densities ranging from ρCO2∼0to0.9g∕cm3. The intensity of scattering from CO2-saturated Vycor porous glass can be described by a two-phase model which suggests that CO2 does not adsorb on the pore walls and fills the pore space uniformly. In CO2-saturated aerogels an adsorbed phase is formed with a density substantially higher that of the bulk fluid, and neutron transmission data were used to monitor the excess adsorption at different pressures. The results indicate that adsorption of CO2 is significantly stronger in aerogels than in activated carbons, zeolites, and xerogels due to the extremely high porosity and optimum pore size of these materials. SANS data revealed the existence of a compressed adsorbed phase with the average density ∼1.07g∕cm3, close to the density corresponding to closely packed van der Waals volume of CO2. A three-phase model [W. L. Wu, Polymer 23, 1907 (1982)] was used to estimate the volume fraction ϕ3 of the adsorbed phase as a function of the fluid density, and gave ϕ3∼0.78 in the maximum adsorption regime around ρCO2∼0.374g∕cm3. The results presented in this work demonstrate the utility of SANS combined with the transmission measurements to study the adsorption of supercritical fluids in porous materials.
Heterodyne double-channel polarimeter for mapping birefringence and thickness of flat glass panels
Authors: Protopopov Vladimir V. , Cho Sunghoon , Kim Kwangso , Lee Sukwon , Kim Hyuk , Kim Daesuk
Published: May 2006

A new cross-polarized heterodyne optical technique is developed for two-dimensional (2D) simultaneous mapping of both birefringence and thickness variations in large flat glass panels commonly used in liquid-crystal displays (LCDs). Weak depolarization of a linearly polarized probe beam due to glass birefringence is detected by means of heterodyne mixing of the two cross-polarized and frequency shifted waves generated by Zeeman-type laser. Amplitude variations of the transmitted laser beam due to interference of the partial waves reflected from the both sides of a sample provide information about glass thickness. Measurements are being performed at the intermediate frequency of 2.3MHz, providing several orders of magnitude higher speed of data acquisition with respect to traditional polarimeters. That high speed of measurements makes it possible to perform quality assessment of LCD glass panels not only in few randomly chosen points as it was in common practice before but to obtain entire 2D maps of both birefringence and thickness variations with millimeter scale spatial resolution. The medium-scale prototype of the LCD glass inspection system is developed and tested. Design and performance of the prototype are described.