bluuebunny/crossref_metadata_2025 huggingface dataset:
A unique strain of Leptospira isolated from a patient with pulmonary haemorrhages in the Andaman Islands: a proposal of serovar portblairi of serogroup Sehgali
Authors: VIJAYACHARI P. , HARTSKEERL R. A. , SHARMA S. , NATARAJASEENIVASAN K. , ROY S. , TERPSTRA W. J. , SEHGAL S. C.
Published: July 2004

Leptospirosis is endemic in the Andaman Islands, often occurring as outbreaks during the post-monsoon period. Pulmonary involvement is common and associated with high morbidity and mortality. During the investigation of an outbreak in North Andaman in 1996 an isolate was recovered from the blood of a patient with fever, headache, body aches and haemoptysis with respiratory distress as presenting symptoms. The isolate was characterized using the cross-agglutination absorption test (CAAT) and monoclonal antibodies (mAbs). The isolate showed typical morphology and characteristic motility of the genus Leptospira. Growth was inhibited at 13 °C and in the presence of 8-azaguanine. The isolate could not be identified with grouping sera representing 25 serogroups, CAAT and mAbs. A new serovar of a new serogroup is proposed. Genetic characterization using polymerase chain reaction (PCR) followed by sequencing of the PCR product and randomly amplified polymorphic DNA fingerprinting (RAPD) showed that the isolate was genetically similar to L. interrogans sensu stricto.
Magnitude and distribution of acute, self-reported gastrointestinal illness in a Canadian community
Authors: MAJOWICZ S. E. , DORÉ K. , FLINT J. A. , EDGE V. L. , READ S. , BUFFETT M. C. , McEWEN S. , McNAB W. B. , STACEY D. , SOCKETT P. , WILSON J. B.
Published: July 2004

To estimate the magnitude and distribution of self-reported, acute gastrointestinal illness in a Canadian-based population, we conducted a retrospective, cross-sectional telephone survey of approximately 3500 randomly selected residents of the city of Hamilton (Ontario, Canada) from February 2001 to February 2002. The observed monthly prevalence was 10% (95% CI 9·94–10·14) and the incidence rate was 1·3 (95% CI 1·1–1·4) episodes per person-year; this is within the range of estimates from other developed countries. The prevalence was higher in females and in those aged <10 years and 20–24 years. Overall, prevalence peaked in April and October, but a different temporal distribution was observed for those aged <10 years. Although these data were derived from one community, they demonstrate that the epidemiology of acute gastrointestinal illness in a Canadian-based population is similar to that reported for other developed countries.
Dietary intake and domestic food preparation and handling as risk factors for gastroenteritis: a case-control study
Authors: MITAKAKIS T. Z. , WOLFE R. , SINCLAIR M. I. , FAIRLEY C. K. , LEDER K. , HELLARD M. E.
Published: July 2004

Cases of gastroenteritis were examined to identify if dietary intake prior to an episode and food-handling and storage practices in the home were risk factors for illness. Cases and controls completed a dietary questionnaire after an event or when well, and questionnaires concerning food-handling, storage and general food-hygiene practices. Comparing cases to themselves when well, subjects were more likely to have eaten cold sliced salami, fried rice and foods cooked elsewhere, and to have had a baby in nappies in the house (OR 1·52–6·24, P[les ]0·01). Cases compared to non-cases were more likely to have bought frozen poultry, have eaten foods cooked elsewhere and to have had a baby in nappies in the house (OR 1·44–2·05, P[les ]0·01). Although food-handling and storage practices are considered important, we were unable to detect an association in this study.
Incidence and risk factors of HCV and HIV infections in a cohort of intravenous drug users in the North and East of France
Authors: LUCIDARME D. , BRUANDET A. , ILEF D. , HARBONNIER J. , JACOB C. , DECOSTER A. , DELAMARE C. , CYRAN C. , VAN HOENACKER A.-F. , FRÉMAUX D. , JOSSE P. , EMMANUELLI J. , LE STRAT Y. , DESENCLOS J.-C. , FILOCHE B.
Published: July 2004

In order to evaluate the incidence and risk factors of infection by hepatitis C virus (HCV) among injecting drug users (IDUs), we conducted a prospective cohort study of HCV- and human immunodeficiency virus (HIV)-negative IDUs in the North and East of France. A total of 231 HCV and HIV IDUs who had injected drugs at least once in their lifetime were followed up every 3 months over a 12-month period. Serum anti-HCV and anti-HIV were tested at inclusion in the study and at the end of the follow-up. Data on injecting practices were collected at inclusion and at each visit. Of the 231 participants included, 165 (71·4%) underwent a final HCV and HIV serum test. The incidence was nil for HIV infection and 9/100 person-years (95% CI 4·6–13·4) for HCV infection. In a multivariable analysis, we found that syringe and cotton sharing were the only independent predictive factors of HCV seroconversion.
Theatres of litigation: Stage music at the Théâtre de la Renaissance, 1838–1840
Authors: EVERIST MARK
Published: July 2004

From 1807 to 1864, Parisian music drama was governed by a system of licences that controlled the repertory of its three main lyric theatres: the Opéra (variously Académie Royale, Nationale and Impériale de Musique), the Théâtre-Italien and the Opéra-Comique. Between 1838 and 1840, the Théâtre de la Renaissance gained a licence to put on stage music, and quickly succeeded in establishing a reputation for energetic management, imaginative programming together with artistically and financially successful performances. It could do this only by exploiting what were effectively newly invented types of music drama: vaudeville avec airs nouveaux and opéra de genre. The invented genres however brought the theatre into legal conflict with the Opéra-Comique and Opéra respectively, and opened up a domain of jurisprudence –associated with repertory rather than copyright – hitherto unsuspected.
/s/-deletion in Old French and the aftermath of compensatory lengthening
Authors: PICARD MARC
Published: July 2004

It has recently been argued by Gess (2001) that the long vowels resulting from the compensatory lengthening that emerged in the wake of preconsonantal /s/-deletion in Old French had all been shortened by the sixteenth century. Given that many of these long vowels are still present in Canadian French, this conclusion cannot possibly be correct. What will be shown here is precisely how Gess' methodology led him to obtain such counterfactual results.
Code and Norm Revisited
Authors: KLIFFER MICHAEL D.
Published: July 2004

This paper deals with the relationship between rules and conventionality, as reflected in a case study of the two structures N1de N2 and N1du N2. Most occurrences of these can be explained via two rules which evoke ease of referent identification and are a subset of the principles governing the ± definiteness opposition in French. Via dictionaries and Google searches, however, we detect variation that our rules cannot predict, typically when N2 is non-countable and abstract. Local semantic contrasts, i.e. dependent on the lexical content of N1 or N2, further complicate the picture. We conclude that Coseriu's Norm, alias conventionality, must be recognized as a factor coexisting with the rules.
Interactions between Neisseria meningitidis and human cells that promote colonisation and disease
Authors: Corbett Anne , Exley Rachel , Bourdoulous Sandrine , Tang Christoph M.
Published: July 2004

Neisseria meningitidis is the leading cause of bacterial meningitis, a potentially fatal condition that particularly affects children. Multiple steps are involved during the pathogenesis of infection, including the colonisation of healthy individuals and invasion of the bacterium into the cerebrospinal fluid. The bacterium is capable of adhering to, and entering into, a range of human cell types, which facilitates its ability to cause disease. This article summarises the molecular basis of host–pathogen interactions at the cellular level during meningococcal carriage and disease.
Prevalence and determinants of nasal colonization with antibiotic-resistant Staphylococcus aureus among unselected patients attending general practitioners in Germany
Authors: LIETZAU S. , STÜRMER T. , ERB A. , VON BAUM H. , MARRE R. , BRENNER H.
Published: July 2004

Although the great majority of antibiotics are prescribed outside hospitals, little is known about the prevalence and determinants of antibiotic resistance in the group of outpatients. Nasal swabs were taken from 627 consecutive patients aged 40 years or above attending general practitioners in Southern Germany. Staphylococcus aureus was cultured and minimal inhibitory concentrations to various antibiotics were tested. Nasal swabs of 152 patients were positive for S. aureus. Prevalence of resistance was 68·3, 8·3 and 0·7% for penicillin G, erythromycin, and oxacillin respectively. Antibiotic use within the last month was associated with erythromycin resistance [adjusted odds ratio (OR) 7·4; 95% confidence interval (CI) 1·0–53]. Besides a high prevalence of resistance to penicillinase-instable antibiotics we found only one (0·7%) methicillin-resistant S. aureus. Recent antibiotic use was associated with increased resistance to erythromycin.
Frictional healing of quartz gouge under hydrothermal conditions: 1. Experimental evidence for solution transfer healing mechanism
Authors: Nakatani Masao , Scholz Christopher H.
Published: July 2004

Experiments on the frictional properties of quartz gouge under hydrothermal conditions have revealed a new fault healing mechanism that operates only at elevated temperature in the presence of liquid‐phase water. This distinguishes it from the well‐known “Dieterich‐type” healing that also operates at room temperature and depends only on the chemical activity of water and not on its phase. The requirement for liquid water to be present is diagnostic of some form of solution transfer being the underlying process. Furthermore, the new healing mechanism operates when the aqueous pore fluid is in chemical equilibrium with silica, indicating solution transfer with only local mass redistribution, such as pressure solution. This new solution transfer healing mechanism has the same logarithmic form, Δμ = b ln (th/tc + 1), as Dieterich‐type healing. Its b value was 0.010–0.014, with no clear temperature dependence in the range 100–200°C, and its magnitude is not very different from that of Dieterich‐type healing. It is distinguished by a cutoff time, tc, many orders of magnitude greater than the Dieterich‐type mechanism. This parameter decreases exponentially with temperature, indicating an apparent activation energy of 54 kJ/mol. This mechanism also has a critical slip distance ∼500 μm, much greater than the 10 μm typical of Dieterich‐type healing. Comparison of the manifestations of this solution transfer healing in velocity step and slide‐hold‐slide tests indicates that this mechanism is compatible with the rate‐state friction law, but its different parameter values may have new implications for earthquake physics.
Laufey Regio: A newly discovered topographic rise on Venus
Authors: Brian Antony W. , Stofan Ellen R. , Guest John E. , Smrekar Suzanne E.
Published: July 2004

Laufey Regio is a 0.5 km high, elongate topographic rise, measuring 1000 by 2000 km, located within northern Navka Planitia, Venus. It is dominated by two large volcanoes, Var and Atanua Montes, and numerous coronae with associated flow deposits. The area has been geologically mapped, showing that large‐scale edifice formation focused at Var and Atanua Montes and overlapped in time with the formation of smaller coronae. Several coronae and volcanoes have had complex and protracted histories with multiple episodes of volcanism and tectonism, supporting a nondirectional history for this region. The broad topography of the rise is surrounded by a concentric set of wrinkle ridges interpreted to have formed after the onset of centralized volcanism. Admittance studies indicate both bottom and top loading, but lithospheric parameters are not well constrained. Top‐loading models give a range of 0–48 km for elastic thickness (Te) and 35–115 km for crustal thickness. We interpret the Te range as most likely indicating isostatic compensation. Bottom‐loading models yield lower bounds of 30–75 km for Te and 32–74 km for the apparent depth of compensation (ADC). The combination of the large Te and low topography indicates that the plume is no longer active. Bottom loading and a small ADC may indicate that a layer of low‐density residuum, produced by pressure release melting in the now extinct plume, is partially supporting the topography. On the basis of its broad, regional topography, abundant volcanism, and gravity signature, we interpret Laufey to be a volcano‐dominated rise in a late stage of evolution.
Nitrogen deposition and increased carbon accumulation in ombrotrophic peatlands in eastern Canada
Authors: Turunen Jukka , Roulet Nigel T. , Moore Tim R. , Richard Pierre J. H.
Published: July 2004

Recent and long‐term accumulation rates of carbon (C), using 210Pb‐ and 14C‐dating, were examined in 23 ombrotrophic peatlands in eastern Canada, where average 1990–1996 atmospheric wet nitrogen (N) deposition ranged from 0.3 to 0.8 g N m−2 yr−1. The average recent rate of C accumulation (RERCA) over the past 150 years was 73 ± 17 (SD) g C m−2 yr−1, ranging from 40 to 117 g C m−2 yr−1. The difference in RERCA between hummocks (78 g C m−2 yr−1) and hollows (65 g C m−2 yr−1) was significant. Increased RERCA over the past 50 years was found in hummocks and hollows in regions of higher N deposition and related to both elevated N deposition and growing degree‐days above +5°C. There was a statistically significant positive relationship between N deposition alone and present‐day C accumulation in both hummocks and hollows (R2 = 0.28 and 0.38, respectively). Recent N accumulation was significantly larger in high N deposition regions. The total average aboveground vegetation biomass of hollows and hummocks did not differ significantly with N deposition. However, a significantly larger vascular plant leaf biomass was found in both hollows and hummocks of the high N deposition class than in the low N deposition class (>0.6 and <0.4 g m−2 yr−1, respectively). The average long‐term apparent rate of C accumulation (LORCA) at 15 sites was 19 ± 8 (SD) g C m−2 yr−1, with no significant difference due to age of peat inception, latitude, or continentality.
High‐resolution animated tectonic reconstruction of the South Pacific and West Antarctic Margin
Authors: Eagles Graeme , Gohl Karsten , Larter Robert D.
Published: July 2004

An animated reconstruction shows South Pacific plate kinematics between 90 and 45 Ma, using the satellite‐derived gravity anomaly field, interpolated isochrons and plate rotation parameters from both published and new work on marine geophysical data. The Great South Basin and Bounty Trough, New Zealand, are shown as the earliest Pacific–Antarctic plate boundary that opened before 83 Ma. The earliest true Pacific–Antarctic seafloor formed within the eastern parts of this boundary, but later and farther west, seafloor formed within its Antarctic flank. After 80 Ma, the Bellingshausen plate converged with an oceanic part of the Antarctic plate to its east, while its motion simultaneously caused rifting in continental Antarctica to the south. The Pacific–Bellingshausen spreading center developed a set of long offset transform faults that the Pacific–Antarctic plate boundary inherited around chron C27 when the Bellingshausen plate ceased to move independently as part of a Pacific‐wide plate tectonic reorganization event. Southwest of these transforms the Pacific–Antarctic Ridge saw an increase in transform‐fault segmentation by ∼58 Ma. One of the long offset Pacific–Bellingshausen transforms, referred to as “V,” was modified during the C27 reorganization event when a Pacific–Antarctic–Phoenix triple junction initiated on its southern edge. Eastern parts of “V” started to operate in the Pacific–Phoenix spreading system, lengthening it even more, while its western parts operated in the Pacific–Antarctic system. This complicated feature was by‐passed and deactivated by ridge axis propagation to its northwest at ∼47 Ma. We interpret our animation to highlight possible connections between these events.
Dual spacecraft observations of a compression event within the Jovian magnetosphere: Signatures of externally triggered supercorotation?
Authors: Hanlon P. G. , Dougherty M. K. , Krupp N. , Hansen K. C. , Crary F. J. , Young D. T. , Tóth G.
Published: July 2004

By using Cassini as an upstream solar wind monitor, we are able to infer increases in the interplanetary dynamic pressure upstream of Jupiter as the spacecraft approached the planet. Observations are made of the effect that these pressure increases had upon both the fields and particles within the Jovian magnetosphere as measured by the Galileo orbiter, which had subsequently reentered the magnetosphere on the duskside. As the external pressure increased, so too did the total field magnitude at Galileo (in particular the Bz and Bϕ components). In addition, strongly leading field angles were observed following the onset of the compression and strongly lagging fields during reexpansion. These observations are consistent with the concept of external control of the angular velocity of the magnetospheric plasma due to conservation of angular momentum within the system. Heating of the plasma can be seen as a pronounced increase in particle flux as measured by the Energetic Particles Detector (EPD) instrument aboard Galileo. Changes in plasma velocity inferred from energetic particle anisotropies at Galileo appear to be consistent with the behavior of the changing magnetic field angle. The overall behavior and response time of the system appears to be consistent with recently published theoretical modeling of the Jovian magnetosphere‐ionosphere coupling system.
In‐flight calibration of the Cassini‐Radio and Plasma Wave Science (RPWS) antenna system for direction‐finding and polarization measurements
Authors: Vogl Dieter F. , Cecconi Baptiste , Macher Wolfgang , Zarka Philippe , Ladreiter Hans Peter , Fédou Pierre , Lecacheux Alain , Averkamp Terry , Fischer Georg , Rucker Helmut O. , Gurnett Donald A. , Kurth William S. , Hospodarsky George B.
Published: July 2004

One major objective of the Cassini mission is the analysis of Saturnian radio emissions of magnetospheric (auroral) as well as atmospheric (lightning) origin. The Radio and Plasma Wave Science (RPWS) experiment is designed to measure the full polarization and the wave vector of the incoming radio waves, allowing us to retrieve information on source locations and emission modes. For that purpose, RPWS uses a two‐channel receiver, connected to two electric monopoles (selected among three), which measures the voltages induced by the electric field of the incident waves and their various correlations. The accuracy of retrieved source locations depends directly on the precise knowledge of the orientation of the three effective monopole axes and lengths, which do not coincide with the physical ones owing to interaction with the spacecraft body. Antenna calibration aims at determining the so‐called effective length vector of each antenna (combining orientation and length information). For that purpose, roll maneuvers of the Cassini spacecraft were performed before and after the Jupiter flyby, at distances such that Jovian radio sources can be identified with the planet's center but still provide a high signal‐to‐noise ratio. The resulting modulations of the measured signals allow us to derive the orientation and length of the effective antennas. The analysis is performed in two steps: first, the Stokes parameters (wave polarization) are determined using approximate antenna orientations derived from laboratory measurements on a scale model of the spacecraft. Second, measurements with high signal‐to‐noise ratio and pure circular polarization are selected and used for the determination of the effective length vectors of the RPWS antennas. Two methods have been developed for inverting the system of equations relating antenna parameters, wave parameters, and measurements (least squares fit and analytical inversion), both of which provide consistent results and present different advantages and limitations which are discussed. A final set of antenna parameters to be used for direction finding studies with the RPWS experiment is obtained.
Jovian cusp processes: Implications for the polar aurora
Authors: Bunce E. J. , Cowley S. W. H. , Yeoman T. K.
Published: July 2004

Recently, high temporal and spatial resolution Hubble Space Telescope (HST) imaging in the ultraviolet (UV) has revealed a new feature in Jupiter's polar aurora. Of highly variable intensity, while remaining persistently near local noon, a polar “spot” of aurora has been suggested to be associated with the jovian cusp. The main jovian X‐ray source also appears to be colocated with this UV emission and is characteristically pulsed with a period of ∼45 min. Here we take up the suggestion that these emissions correspond to the cusp, i.e., where magnetosheath plasma gains entry to the jovian magnetosphere. We first observe that without acceleration, the largest precipitating energy fluxes are associated with magnetosheath protons, but these produce only ∼0.4–4 kR of UV emission, well below that which is observed (>100 kR). Therefore acceleration must be present. We thus investigate the possibility that the UV and X‐ray emissions are associated with pulsed reconnection at the dayside magnetopause, with an interpulse period estimated to be 40–50 min, hence providing a possible explanation for the pulsed X‐ray signatures. Based upon the approximate bimodality of solar wind conditions at Jupiter, we have developed two conceptual models, “slow” and “fast” flow models corresponding to low and high values of the interplanetary magnetic field strength, respectively, of the twin‐vortical flows which occur as a result of pulsed dayside reconnection, and the bipolar field‐aligned currents which are also present. We find that peak field‐aligned currents due to the vortical flows in the two models are ∼1.15 and 8.13 μA m−2, respectively, for the slow and fast models. We subsequently consider conditions under which magnetospheric and cusp particle populations can carry these field‐aligned currents, by estimating the field‐aligned voltages which will be present and the energy fluxes and auroral output which results. Although the details depend upon the model assumptions, for the slow flow model the reconnection pulses produce two adjacent bright (>100 kR) “spots” or “arcs” of emission of order a few 1000 km along the open‐closed field line boundary and a few 100 km wide, separated by a few 1000 km, comparable with observations. The X‐ray emission in this slow flow scenario is negligible due to low voltages associated with the flow vortices. In the fast flow model, overall, the emission takes the form of an intense ∼10 MR arc extending ∼10,000 km along the open‐closed field line boundary, with a “gap” between electron and ion contributions. We also find that in this case magnetospheric O2+ in the region of the downward currents is accelerated sufficiently to produce X‐rays, with intensities ∼few kR and peak power outputs of a few GW, in good agreement with observations.
Inversion for anisotropy from non‐double‐couple components of moment tensors
Authors: Vavryčuk Václav
Published: July 2004

An inversion method for retrieving seismic anisotropy from non‐double‐couple components of seismic moment tensors is presented. The method requires a set of highly accurate moment tensors of earthquakes that occurred in a homogeneous anisotropic focal area on differently oriented faults. In contrast to standard methods retrieving anisotropy from travel times or from shear wave splitting, which yield an overall anisotropy averaged along a whole ray path, the presented method yields a local value of anisotropy just in the focal area. The method is robust, being able to retrieve the orientation as well as strength of anisotropy even for low anisotropy symmetries as for orthorhombic symmetry. The method can utilize the moment tensors constrained to have zero trace, but using unconstrained moment tensors is advantageous. The method is applied to retrieving anisotropy in the Tonga subduction zone using moment tensors of deep‐focus earthquakes reported in the Harvard centroid moment tensor catalog. The inversion is complemented by tests on synthetic data to assess its stability and the accuracy of the results. The inversion indicates that the subduction zone is anisotropic with orthorhombic symmetry. The orientation of the intra‐slab anisotropy is defined by axes (azimuth/dip) a1 = 320°/54°, a2 = 121°/38°, and a3 = 223°/81°. The errors in the azimuth and dip are about 5°. The first and second axes lie along the downdip motion of the slab and along the normal to the slab, respectively. The strength of the P, S1, and S2 anisotropy is of 7.3 ± 1.5%, 13.4 ± 2.5%, and 12.6 ± 3.5%, respectively. The errors of anisotropy strength are only rough estimates, which reflect random but not systematic errors in the moment tensors used in the inversion. The values for anisotropy strength in the slab are remarkably higher than those observed in the surrounding mantle. The symmetry axes of anisotropy coincide with the principal stress directions in the slab. This manifests a primary impact of stress on anisotropy formation. The retrieved anisotropy in the slab can serve as an additional constraint on its structure and mineralogical composition.
Frictional healing of quartz gouge under hydrothermal conditions: 2. Quantitative interpretation with a physical model
Authors: Nakatani Masao , Scholz Christopher H.
Published: July 2004

The companion paper by Nakatani and Scholz [2004] shows that a hydrothermal frictional healing mechanism results from local solution transfer. Here we evaluate this mechanism with the model of Brechet and Estrin [1994], which assumes that the healing occurs by stress‐driven asperity creep. The absence of a clear temperature dependence of the healing parameter b in the narrow tested range of 100–200°C is consistent with the model's prediction. The analysis also indicates that the mechanism involves a high stress assist parameter Ωσ = 200 kJ/mol, which is consistent with the contact stress being the indentation hardness, σ ∼ 10 GPa, and the activation volume Ω being the molar volume, both of which are reasonable. For this to be consistent with the observed temperature enhanced kinetics of healing also requires that the activation energy exceed 200 kJ/mol. This is much higher than the 20–70 kJ/mol known for low contact stress pressure solution. The analysis of several previously published studies of hydrothermal healing of hard silicates yielded the same results. Hence, if the underlying process is stress driven, it must have a different mechanism at high stress than at low stress. Alternatively, a solution transfer mechanism driven by something other than stress could be the underlying mechanism, but this is inconsistent with other aspects of our experimental results. On the other hand, the same analysis of phenomena that are independently inferred to proceed under relatively low contact stress yielded the parameter values consistent with low‐stress pressure solution.
Rayleigh scattering cross sections of O2 at wavelengths longer than 180 nm
Authors: Simbotin I. , Jamieson M. J. , Dalgarno A.
Published: July 2004

Rayleigh scattering of solar radiation by oxygen molecules is an important contributor to the photon flux in the atmosphere at wavelengths longer than the threshold for direct photodissociation of O2 near 180 nm. We carry out detailed calculations of Rayleigh scattering cross sections of O2 at wavelengths from 180 to 205 nm in the region of the discrete Schumann‐Runge band system. The cross sections contain numerous resonance structures, whose characteristics we identify. Beyond 205 nm we show that the cross sections diminish rapidly before taking up the known variation as the inverse fourth power of the wavelength at long wavelengths. We present detailed results for cross sections for scattering by O2 in individual rotational levels of the ground vibrational state sufficient to allow the calculation of the Rayleigh scattering cross sections at atmospheric temperatures.
Particle characteristics following cloud‐modified transport from Asia to North America
Authors: Brock Charles A. , Hudson Paula K. , Lovejoy Edward R. , Sullivan Amy , Nowak John B. , Huey L. Gregory , Cooper Owen R. , Cziczo Daniel J. , de Gouw Joost , Fehsenfeld Fred C. , Holloway John S. , Hübler Gerhard , Lafleur Bernard G. , Murphy Daniel M. , Neuman J. Andrew , Nicks Dennis K. , Orsini Douglas A. , Parrish David D. , Ryerson Thomas B. , Tanner David J. , Warneke Carsten , Weber Rodney J. , Wilson James C.
Published: July 2004

Fast response measurements of particle size distributions, bulk submicron particle composition, and single particle composition were made aboard the NOAA WP‐3D research aircraft in the free troposphere over the eastern Pacific Ocean and the western coast of North America. Measurements of gas‐phase compounds and meteorological analysis show evidence of long‐range transport of layers of aerosol particles from anthropogenic and biomass‐burning sources in eastern Asia. Layers of crustal particles with no evident sources were also encountered. Measurements of substantially enhanced particulate sulfate mass and gas‐phase H2SO4 encountered during one transport event were interpreted with the aid of a numerical model of particle formation and growth and trajectory analysis. The observed particle size distributions and sulfate mass concentration were consistent with the simulation, indicating that the particles were formed over the mid‐Pacific from gas‐to‐particle conversion following long‐range transport of SO2 through a midlatitude cyclonic system. Such cloud systems appear to effectively scavenge most pre‐existing particle mass, but can allow transport of gas‐phase precursors which substantially alter downstream particle microphysical and chemical properties.
Impact of Asian emissions on observations at Trinidad Head, California, during ITCT 2K2
Authors: Goldstein Allen H. , Millet Dylan B. , McKay Megan , Jaeglé Lyatt , Horowitz Larry , Cooper Owen , Hudman Rynda , Jacob Daniel J. , Oltmans Sam , Clarke Andrew
Published: July 2004

Field measurements of a wide suite of trace gases and aerosols were carried out during April and May 2002, along with extensive chemical transport modeling, as part of the NOAA Intercontinental Transport and Chemical Transformation study. Here, we use a combination of in‐situ ground‐based measurements from Trinidad Head, CA, chemical transport modeling, and backward trajectory analysis to examine the impact of long‐range transport from Asia on the composition of air masses arriving at the California coast at the surface. The impact of Asian emissions is explored in terms of both episodic enhancements and contribution to background concentrations. We find that variability in CO concentrations at the ground site was largely driven by North American emissions, and that individual Asian plumes did not cause any observable pollution enhancement episodes at Trinidad Head. Despite this, model simulations suggest that Asian emissions were responsible for 33% of the CO observed at Trinidad Head, providing a larger mean contribution than direct emissions from any other region of the globe. Surface ozone levels were found to depend primarily on local atmospheric mixing, with surface deposition leading to low concentrations under stagnant conditions. Model simulations suggested that on average 4 ± 1 ppb of ozone (10% of observed) at Trinidad Head was transported from Asia.
Gamma‐Ray, Neutron, and Alpha‐Particle Spectrometers for the Lunar Prospector mission
Authors: Feldman W. C. , Ahola K. , Barraclough B. L. , Belian R. D. , Black R. K. , Elphic R. C. , Everett D. T. , Fuller K. R. , Kroesche J. , Lawrence D. J. , Lawson S. L. , Longmire J. L. , Maurice S. , Miller M. C. , Prettyman T. H. , Storms S. A. , Thornton G. W.
Published: July 2004

Gamma‐Ray, Neutron, and Alpha‐Particle Spectrometers (GRS, NS, and APS, respectively) were included in the payload complement of Lunar Prospector (LP). Specific objectives of the GRS were to map abundances of Fe, Ti, Th, K, Si, O, Mg, Al, and Ca to depths of 20 cm. Those of the NS were to search for water ice to depths of 100 cm near the lunar poles and to map regolith maturity. Objectives of the APS were to search for, map, and provide a measure of the time history of gaseous release events at the lunar surface. The purpose of this paper is to document the mechanical, analog electronic, digital electronic, and microprocessor designs of the suite of spectrometers, present a representative sample of the calibrated response functions of all sensors, and document the operation of all three LP spectrometers in sufficient detail as to enable the full knowledgeable use of all data products that were archived in the Planetary Data System for future use by the planetary‐science community.
Two‐dimensional study of leaky modes in microstrip line with a semi‐infinite cover layer
Authors: Rodríguez‐Berral R. , Mesa F. , Medina F.
Published: July 2004

This work presents a two‐dimensional (2‐D) study of the modal spectrum of a single microstrip and a pair of coupled microstrip lines with an upper dielectric half‐space. This 2‐D study is postulated as the necessary step previous to the 3‐D investigation of the potential applications of leaky‐wave antennas radiating in an environment susceptible to be modeled by a dielectric half‐space. Thus the nature and the possible transitions of the modal spectrum will be characterized for a wide range of values of the permittivity of the upper half‐space (ɛu). From a physical rationale, the modal spectrum is expected to comprise only leaky modes for values of ɛu greater than the permittivity of the line substrate (ɛ). This hypothesis is corroborated by the computed numerical results, which, for the case of the microstrip with an air gap, also show that the above assertion is satisfied even for values of ɛu less than ɛ. Although the nature of the mathematical transition from bound to leaky modes could not be rigorously established, there has been always found a “physical” transition from each fundamental bound mode (BM) to a space‐wave leaky mode (SPWLM). This type of direct physical transition from a fundamental BM to a SPWLM, which is not allowed in a frequency evolution, has been proved to be mathematically viable.
Unexpected water content profiles under flux‐limited one‐dimensional downward infiltration in initially dry granular media
Authors: Shiozawa Sho , Fujimaki Haruyuki
Published: July 2004

Distinct water‐content profiles, having saturated θ‐bumps at and immediately behind wetting fronts, were observed in narrow columns (9 mm ID) of homogeneous air‐dried glass beads under downward one‐dimensional infiltration with applied water fluxes at lower than the saturated hydraulic conductivity. The infiltrating water content profiles and the position of the wetting front as a function of time were also calculated based on Richards' equation using an independently measured hydraulic conductivity function K(θ), and water retention characteristic θ(h), of the drainage process, and by applying a pressure boundary condition, hwe, which is almost atmospheric pressure, at the moving wetting front. The good agreement between the calculated profiles and the observed confirms that the dynamic water entry pressure hwe (where θ(hwe) is the saturated water content), does exist for air‐dried glass beads, although it is in contradiction to the modern theory of unsaturated water flow in porous media. This physical property of dry media creates an upward negative pressure profile behind the wetting front that would inevitably produce finger flow if the column diameter were larger. At the wetting front, the water content and pressure should be completely discontinuous at the level of pore size, and hence Darcy's equation cannot be applied across the interface between the air‐dried and saturated media.
Influence of bed roughness on dune and megaripple generation
Authors: Idier Déborah , Astruc Dominique , Hulscher Suzanne J. M. H.
Published: July 2004

Richards [1980] conjectured that megaripples of the continental shelf are due to a seabed instability in the presence of seabed ripples. Towards a better understanding of this megaripple formation process, we use a morphodynamical numerical model to investigate the bed roughness influence on the bed load–induced linear stability of a sandy bed. We find that the linearly most amplified mode shifts from a dune mode (grain roughness) towards a megaripple mode (large bed roughness). Then, we discuss how megaripples could be generated over a flat bed and over dunes.
Tsunami sources in the southern California bight
Authors: Borrero José C. , Legg Mark R. , Synolakis Costas E.
Published: July 2004

Locally generated tsunamis due to faulting or slope failures offshore southern California threaten nearby coastal cities. Disruption of operations at port facilities due to tsunami attack could severely impact the regional and national economies. This study examines three faults and two landslides scenarios as potential tsunami sources. Computed runup ranges from 0.5 to 6 m depending on the source and location. Bathymetric features such as the broad San Pedro Shelf are shown to contribute to tsunami wave focusing while retarding tsunami arrival times, suggesting the usefulness of an early warning system.
Altitude dependence of atmospheric temperature trends: Climate models versus observation
Authors: Douglass David H. , Pearson Benjamin D. , Singer S. Fred
Published: July 2004

As a consequence of greenhouse forcing, all state‐of‐the‐art general circulation models predict a positive temperature trend that is greater for the troposphere than the surface. This predicted positive trend increases in value with altitude until it reaches a maximum ratio with respect to the surface of as much as 1.5 to 2.0 at about 200–400 hPa. However, the temperature trends from several independent observational data sets show decreasing as well as mostly negative values. This disparity indicates that the three models examined here fail to account for the effects of greenhouse forcings.
Upwelling response to coastal wind profiles
Authors: Capet X. J. , Marchesiello P. , McWilliams J. C.
Published: July 2004

The spatial structure of nearshore wind, as measured by aircraft and analyzed in high‐resolution atmospheric models (e.g., COAMPS), has strong influence on the patterns of upwelling circulation, surface temperature, and biogeochemical processes in coastal regions. Using a regional oceanic model for both the Southern California Bight and the Central California Coast, we demonstrate the nature of this upwelling sensitivity and infer that present wind analyses do not adequately determine the most important wind properties, viz., the strength of the nearshore curl and the speed drop‐off near the coast.
Disparity of tropospheric and surface temperature trends: New evidence
Authors: Douglass David H. , Pearson Benjamin D. , Singer S. Fred , Knappenberger Paul C. , Michaels Patrick J.
Published: July 2004

Observations suggest that the earth's surface has been warming relative to the troposphere for the last 25 years; this is not only difficult to explain but also contrary to the results of climate models. We provide new evidence that the disparity is real. Introducing an additional data set, R2 2‐meter temperatures, a diagnostic variable related to tropospheric temperature profiles, we find trends derived from it to be in close agreement with satellite measurements of tropospheric temperature. This suggests that the disparity likely is a result of near‐surface processes. We find that the disparity does not occur uniformly across the globe, but is primarily confined to tropical regions which are primarily oceanic. Since the ocean measurements are sea surface temperatures, we suggest that the disparity is probably associated with processes at the ocean‐atmosphere interface. Our study thus makes unlikely some of the explanations advanced to account for the disparity; it also demonstrates the importance of distinguishing between land, sea and air measurements.
Further evidences for the weakening relationship of Indian rainfall and ENSO over India
Authors: Sarkar Sudipta , Singh Ramesh P. , Kafatos Menas
Published: July 2004

Numerous efforts have been made in the past to understand the effect of Indian monsoon and El Niño/Southern Oscillation (ENSO) over the Indian continent. Various approaches and analysis of datasets covering the last 140 years have shown a dominantly inverse relationship between the ENSO and Indian rainfall. But this dominant coupling between the ENSO and Indian rainfall has been observed to weaken in recent decades. In the present paper, we have analyzed rainfall trend over the Indian sub‐continent and its relation with ENSO. Our results indicate a stronger circulation pattern over the Indian region in last two decades. We have also found that the effect of ENSO has increased in recent years but has failed to influence the Indian rainfall because of the stronger circulation pattern prevailing over India during this time.
Intermediate level circulation of the southwestern part of the East/Japan Sea estimated from autonomous isobaric profiling floats
Authors: Park Young‐Gyu , Oh Kyung‐Hee , Chang Kyung‐Il , Suk Moon‐Sik
Published: July 2004

With trajectory data from autonomous isobaric profiling floats (PALACE, APEX and PROVOR), we obtained a detailed intermediate level circulation pattern over the southwestern part of the East/Japan Sea. The circulation pattern, which is consistent with moored current meter data obtained at a few locations, is largely controlled by the bottom topography. The main features we have found are as follows: 1) a cyclonic circulation along the Korean coast and the continental break around the Ulleung Basin and the western side of Oki Spur to the Yamato Rise, and 2) a cold current from the Japan Basin to the Ulleung Basin through the Ulleung Interplain Gap, which is a part of the anticyclonic flow over the Korea Plateau, a Taylor column.
Raman scattering by ground‐state atomic oxygen
Authors: Sharma Ramesh D.
Published: July 2004

Differential cross sections for Raman scattering between the multiplet levels of the ground electronic state of atomic oxygen are calculated from first principles. The calculated cross sections are in order‐of‐magnitude agreement with the available experimental measurements. The use of a Raman LIDAR (Light Detection and Ranging) has the potential of giving a three‐dimensional map of the density of each of the three fine structure levels of atomic oxygen. Since it was established earlier that the fine structure levels are in local thermodynamic equilibrium (LTE) up to at least 350 km altitude, the Raman LIDAR therefore also has the potential of giving a three‐dimensional map of the temperature of the atmosphere.
Magnetohydrodynamic simulation of an equatorial dipolar paleomagnetosphere
Authors: Zieger B. , Vogt J. , Glassmeier K.‐H. , Gombosi T. I.
Published: July 2004

During polarity reversals of the Earth's internal geomagnetic field, the paleomagnetosphere must have undergone dramatic changes because the core field was essentially different from the present‐day case, where the dipole moment is approximately aligned with the Earth's rotation axis (axial dipole) and perpendicular to the solar wind flow. According to one of the possible transition scenarios, the internal dipole moment, having much reduced in magnitude, could slowly turn around, staying close to the equatorial plane for a significant time. In this paper we present magnetohydrodynamic (MHD) simulations of a so‐called equatorial dipolar paleomagnetosphere, where the internal dipole moment is perpendicular to the rotation axis, i.e., the dipole axis is in the equatorial plane. The magnitude of the dipole moment was chosen as small as one‐tenth of the present value. With such a dipole field orientation, the dipole tilt in GSM coordinates changes, due to the Earth's rotation, between zero and 360 degrees in the course of the day, resulting in an extremely dynamic magnetosphere on the diurnal timescale. As a first approximation, we calculated steady‐state solutions with different dipole tilts, or in other words with different angles between the dipole axis and the Sun‐Earth line, to represent the paleomagnetosphere at different times of the day. We describe the regular diurnal variation of the geomagnetic field‐line configuration and the topology of large‐scale current systems, like the magnetopause currents and the tail current sheet. We investigate the so‐called pole‐on magnetosphere, where the dipole axis is aligned with the Sun‐Earth line, in more details using different solar wind input parameters.
Kinematics of subduction and subduction‐induced flow in the upper mantle
Authors: Schellart W. P.
Published: July 2004

Results of fluid dynamical experiments are presented to model the kinematics of lithospheric subduction in the upper mantle. The experiments model a dense high‐viscosity plate (subducting lithosphere) overlying a less dense low‐viscosity layer (upper mantle). The overriding lithosphere is not incorporated. Several important features of slab behavior were investigated including the temporal variability of hinge line migration, the kinematic behavior of the slab and the subduction‐induced upper mantle flow. Both fixed and free trailing edge boundary conditions of the subducting plate were investigated. Results show that hinge line retreat is a natural consequence of subduction of a negatively buoyant slab. The migration rate increases until the slab approaches the upper‐lower mantle discontinuity, resulting in a decrease in migration rate followed by a renewed increase and finally approaching a steady state. Slab retreat results in mantle flow, with material initially located underneath the slab flowing around the lateral slab edges toward the mantle wedge. Experimental results indicate that all rollback‐induced flow occurs around the lateral slab edges, forcing the hinge line to attain a convex shape toward the direction of retreat. No signs for poloidal flow underneath the slab tip have been detected. Only a small component of toroidal‐type flow was observed underneath slanting slab tips. For a fixed trailing edge, the slab does not sink vertically downward, but sinks at an angle in a regressive manner. For a free trailing edge, slab sinking is oriented more vertically while the surface part of the subducting plate is pulled into the subduction zone.