bluuebunny/crossref_metadata_2025 huggingface dataset:
Spatial distribution of conductances and currents associated with a north-south auroral form during a multiple-substorm period
Authors: Amm O. , Pajunpää A. , Brandström U.
Published: June 2005

Abstract. Using the method of characteristics to invert ground-based data of the ground magnetic field disturbance and of the ionospheric electric field, we obtain spatial distributions of ionospheric conductances, currents, and field-aligned currents (FACs) associated with a north-south auroral form that drifts westwards over northern Scandinavia around 2200 UT on December 2, 1977. This auroral form is one in a sequence of such north-south structures observed by all-sky cameras, and appears 14 min after the last of several breakups during that extremely disturbed night. Our analysis shows that the ionospheric Hall conductance reaches values above 200 S in the center of the form, and upward flowing FACs of up to 25 µA/m2 are concentrated near its westward and equatorward edge. The strong upward flowing FACs are fed by an area of more distributed, but still very strong downward-flowing FACs northeastward of the auroral form. In contrast to the conductances, the electric field is only slightly affected by the passage of the form. We point out similarities and differences of our observations and results to previously reported observations and models of 'auroral fingers', 'north-south aurora', and 'auroral streamers' which are suggested to be ionospheric manifestations of bursty bulk flows in the plasma sheet.Key words. Ionosphere (auroral ionosphere; electric fields and currents) · Magnetospheric physics (magnetosphere · ionosphere interactions)
Lower thermospheric nitric oxide concentrations derived from WINDII observations of the green nightglow continuum at 553.1 nm
Authors: von Savigny C. H. A. , McDade I. C. , Shepherd G. G. , Rochon Y.
Published: June 2005

Abstract. Vertical profiles of nitric oxide in the altitude range 90 to 105 km are derived from 553 nm nightglow continuum measurements made with the Wind Imaging Interferometer (WINDII) on the Upper Atmosphere Research Satellite (UARS). The profiles are derived under the assumption that the continuum emission is due entirely to the NO+O air afterglow reaction. Vertical profiles of the atomic oxygen density, which are required to determine the nitric oxide concentrations, are derived from coordinated WINDII measurements of the atomic oxygen OI 557.7 nm nightglow emission. Data coverage for local solar times ranging from 20 h to 04 h, and latitudes ranging from 42°S to 42°N, is achieved by zonally averaging and binning data obtained on 18 nights during a two-month period extending from mid-November 1992 until mid-January 1993. The derived nitric oxide concentrations are significantly smaller than those obtained from rocket measurements of the airglow continuum but they do compare well with model expectations and nitric oxide densities measured using the resonance fluorescence technique on the Solar Mesosphere Explorer satellite. The near-global coverage of the WINDII observations and the similarities to the nitric oxide global morphology established from other satellite measurements strongly suggests that the NO+O reaction is the major source of the continuum near 553 nm and that there is no compelling reason to invoke additional sources of continuum emission in this immediate spectral region.Key words. Atmospheric composition and structure (airglow and aurora; thermosphere – composition and chemistry; instruments and techniques)
Dynamics and local boundary properties of the dawn-side magnetopause under conditions observed by Equator-S
Authors: Dunlop M. W. , Balogh A. , Baumjohann W. , Haerendel G. , Fornacon K.-H. , Georgescu E. , Nakamura R. , Kokubin S.
Published: June 2005

Abstract. Magnetic field measurements, taken by the magnetometer experiment (MAM) on board the German Equator-S spacecraft, have been used to identify and categorise 131 crossings of the dawn-side magnetopause at low latitude, providing unusual, long duration coverage of the adjacent magnetospheric regions and near magnetosheath. The crossings occurred on 31 orbits, providing unbiased coverage over the full range of local magnetic shear from 06:00 to 10:40 LT. Apogee extent places the spacecraft in conditions associated with intermediate, rather than low, solar wind dynamic pressure, as it processes into the flank region. The apogee of the spacecraft remains close to the magnetopause for mean solar wind pressure. The occurrence of the magnetopause encounters are summarised and are found to compare well with predicted boundary location, where solar wind conditions are known. Most scale with solar wind pressure. Magnetopause shape is also documented and we find that the magnetopause orientation is consistently sunward of a model boundary and is not accounted for by IMF or local magnetic shear conditions. A number of well-established crossings, particularly those at high magnetic shear, or exhibiting unusually high-pressure states, were observed and have been analysed for their boundary characteristics and some details of their boundary and near magnetosheath properties are discussed. Of particular note are the occurrence of mirror-like signatures in the adjacent magnetosheath during a significant fraction of the encounters and a high number of multiple crossings over a long time period. The latter is facilitated by the spacecraft orbit which is designed to remain in the near magnetosheath for average solar wind pressure. For most encounters, a well-ordered, tangential (draped) magnetosheath field is observed and there is little evidence of large deviations in local boundary orientations. Two passes corresponding to close conjunctions of the Geotail spacecraft are analysed to confirm boundary orientation and motion. These further show evidence of an anti-sunward moving depression on the magnetopause (which is much smaller at Equator-S). The Tsyganenko model field is used routinely to assist in categorising the crossings and some comparison of models is carried out. We note that typically the T87 model fits the data better than the T89 model during conditions of low to intermediate KP index near the magnetopause and also near the dawn-side tail current sheet in the dawnside region.Key words. Magnetospheric physics (magnetopause · cusp · and boundary layers; magnetosheath; magneto- spheric configuration and dynamics).
Spacecraft potential control aboard Equator-S as a test for Cluster-II
Authors: Torkar K. , Riedler W. , Fehringer M. , Rüdenauer F. , Escoubet C. P. , Arends H. , Narheim B. T. , Svenes K. , McCarthy M. P. , Parks G. K. , Lin R. P. , Rème H.
Published: June 2005

Abstract. The payload of Equator-S was complemented by the potential control device (PCD) to stabilise the electric potential of the spacecraft with respect to the ambient plasma. Low potentials are essential for accurate measurements of the thermal plasma. The design of PCD is inherited from instruments for Geotail and Cluster and utilises liquid metal ion sources generating a beam of indium ions at several keV. The set-up of the instrument and its interaction with the plasma instruments on board is presented. When the instrument was switched on during commissioning, unexpectedly high ignition and operating voltages of some ion emitters were observed. An extensive investigation was initiated and the results, which lead to an improved design for Cluster-II, are summarised. The cause of the abnormal behaviour could be linked to surface contamination of some emitters, which will be monitored and cured by on-board procedures in future. The mission operations on Equator-S were not at all affected, because of the high redundancy built into the instrument so that a sufficient number of perfectly operating emitters were available and were turned on routinely throughout the mission. Observations of the effect of spacecraft potential control on the plasma remained limited to just one event on January 8, 1998, which is analysed in detail. It is concluded that the ion beam lead to the predicted improvement of the particle measurements even outside the low density regions of the magnetosphere where the effect of spacecraft potential control would have been much more pronounced, and that the similar instruments for the four Cluster-II spacecraft to be launched in 2000 will be very important to ensure accurate plasma data from this mission.Key words. Space plasma physics (active perturbation experiments; spacecraft sheaths · wakes · charging; instruments and techniques)
Psychological consequences of the 1999 earthquake in Turkey
Authors: Tural Ümit , Coşkun Bülent , Önder Emin , Çorapçioǧlu Aytül , Yildiz Mustafa , Kesepara Coşkun , Karakaya Işik , Aydin Mustafa , Erol Ayla , Torun Fuat , Aybar Gaye
Published: June 2005

We explored the prevalence of posttraumatic stress disorder (PTSD) and its relation to demographic characteristics and other risk factors for developing PTSD in a large sample (N = 910) of earthquake survivors living in tent city. Twenty‐five percent of the sample met DSM‐IV criteria for PTSD assessed with the Posttraumatic Stress Disorder Self Test (PTSD‐S). Peritraumatic factors explained the most variance when the risk factors were grouped as demographics, pretraumatic, peritraumatic, and posttraumatic. The study emphasized that PTSD among the earthquake victims was as prevalent in Turkey as after disasters in other developing countries but higher than usually found after disasters in developed countries, and there was a relation between some factors—mostly peritraumatic—and PTSD.
Imagery vividness and perceived anxious arousal in prolonged exposure treatment for PTSD
Authors: Rauch Sheila A. M. , Foa Edna B. , Furr Jami M. , Filip Jennifer C.
Published: June 2005

The present paper examines imagery vividness and anxiety during Prolonged Exposure (PE) for chronic PTSD among 69 female survivors of sexual or nonsexual assault. All participants received between 9 and 12 individual sessions of either PE alone or in combination with cognitive restructuring. As hypothesized, vividness and anxiety ratings from early imaginal exposure sessions were moderately to highly correlated, but these correlations decreased in later sessions. Both subjective distress and vividness decreased significantly with exposure. Greater reductions in subjective distress between the first and last exposure session were related to better outcome. However, contrary to hypothesis, vividness was not related to outcome. Theoretical implications of the results are discussed.
Are avoidance and numbing distinct PTSD symptom clusters?
Authors: Asmundson Gordon J. G. , Stapleton Jennifer A. , Taylor Steven
Published: June 2005

We present the conceptual basis and empirical evidence for considering avoidance and numbing as distinct posttraumatic stress disorder (PTSD) symptom clusters. The majority of data from factor analytic studies supports the position that avoidance and numbing are distinct symptom clusters. As well, the available data suggest that (a) different treatment modalities have differential effects on reducing avoidance but not numbing, (b) patients with more severe pretreatment numbing have poorer treatment outcomes, (c) avoidance and numbing have different patterns of correlation with depression, and (d) they have different correlations with physiological indices of attention. We conclude that avoidance and numbing are distinct PTSD symptom clusters. This distinction has implications for revising current diagnostic criteria. The recognition of this distinction may lead to advances in understanding and treating PTSD.
Development and psychometric validation of a domestic violence coping self‐efficacy measure (DV‐CSE)
Authors: Benight Charles C. , Harding‐Taylor Alexandra S. , Midboe Amanda M. , Durham Robert L.
Published: June 2005

Psychometric properties of a Domestic Violence Coping Self‐Efficacy Measure were examined. Two hundred eighty three women assaulted within the past 6 months were recruited. Internal reliability of the measure was very good (α = .97). Principle components factor analysis indicated one primary factor accounting for 56% of the variance. The measure was positively associated with optimism, adaptive coping, and healthy psychological functioning, and negatively associated with trauma‐related distress, negative mood, and maladaptive coping. A small positive association with social desirability was found. This measure may have significant clinical utility in helping survivors by indicating areas where individuals feel especially vulnerable or empowered.
Preliminary evaluation of a video‐based intervention for older adult victims of violence
Authors: Acierno Ron , Rheingold Alyssa A. , Resnick Heidi S. , Stark‐Riemer Wendy
Published: June 2005

The present study evaluated a brief, video‐based intervention for older adults designed to: provide psychological education regarding common reactions to crime: offer information about healthy coping strategies to manage crime‐related symptomatology: and increase awareness of effective safety planning strategies. Following reporting to police, 116 older adult crime victims were randomly assigned to receive either standard advocate‐based services plus the video‐based intervention or standard advocate services alone. Results indicated that older adult victims assigned to the video condition and assessed later that day exhibited greater awareness of crime‐related symptoms, healthy coping strategies, and safely planning strategies than did the older adult victims assigned to standard practice of care. However, despite knowledge gains, and in contrast to our predictions, no differences on measures of anxiety or depression were evident between the treatment conditions at 6‐week follow up.
Sources of variation in the feeding ecology of the piked spurdog (Squalus megalops): implications for inferring predator–prey interactions from overall dietary composition
Authors: Braccini J. Matías , Gillanders Bronwyn M. , Walker Terence I.
Published: June 2005

Sources of variation in dietary composition were examined in the piked spurdog (Squalus megalops). The species is an opportunistic predator that consumes a wide range of prey items. When importance of prey was measured by weight or occurrence, S. megalops preyed largely on molluscs and teleosts. However, when number of prey was considered, the main items were crustaceans. A bootstrap analysis showed that considerable variability can be expected in the importance of prey items in the species' overall diet. Regional, seasonal, and ontogenetic differences in dietary composition were found, but there were no differences between mature and immature sharks or between males and females. The spatial and temporal variation in diet exhibited by S. megalops and the intrinsic natural variability of the dietary composition of this opportunistic predator suggest that studies that infer predator–prey interactions from overall diet are likely to miss information on the ecological relationships among species and thus account for only part of these interactions.
Second-generation antipsychotics: are their similarities greater than their differences?
Authors: Fleischhacker W. Wolfgang
Published: June 2005

The move towards the use of second-generation antipsychotics for the treatment of schizophrenia has provoked much discussion over how to differentiate between the various second-generation agents available on the market. The aim of this review is to provide information that may help clinicians in the decision-making process. The results of comparative studies on general efficacy measures (such as the Positive and Negative Syndrome Scale [PANSS] and the Brief Psychiatric Rating Scale [BPRS]) and comparative studies on cognition do not clearly favour one second-generation agent over another. However, some differences between second-generation agents have become apparent from studies which have examined specific symptoms such as hostility, suicidal ideation and depression/anxiety. There are also differences between second-generation agents with regard to specific aspects of tolerability. For example, in a number of studies olanzapine is associated with fewer extrapyramidal symptoms (EPS) than risperidone, but treatment with risperidone or amisulpride is associated with less weight gain and somnolence. Some studies have investigated the results of switching patients from one antipsychotic agent to another. They have generally reported a successful switch to a second-generation agent.

Overall, there is not enough scientific evidence available to clearly favour one second-generation antipsychotic agent over another in terms of general efficacy or tolerability. Therefore, clinicians must make an individualised treatment decision, and select the most appropriate antipsychotic agent for each patient.
A century of fungicide evolution
Authors: RUSSELL P. E.
Published: June 2005

Up until the 1940s chemical disease control relied upon inorganic chemical preparations, frequently prepared by the user. Key areas of use were horticulture and vegetable production with key targets being diseases that caused easily recognized damage. After this era and as the damaging effects of more crop diseases became obvious by the use of chemical control, the crop protection industry expanded rapidly and research to discover new active materials began in earnest. As new areas of chemistry were introduced, each one aiming to offer advantages over the previous ones, chemical families were born with research-based companies frequently adopting patent-busting strategies in order to capitalize on the developing fungicides market. Systemic fungicides offered new opportunities in disease control. The rise in Research and Development (R & D) and the increase in the number and quantity of chemicals being applied led to the introduction of regulation in the 1950s, initially on a voluntary basis, but now strictly controlled by legal obligations. In the 1960s, the market switched from horticulture and vegetables to one in which the main agricultural crops dominated. The cereal market, initially based on barley, moved to the current dominant market of wheat. The costs of R & D have risen dramatically in recent years and have become dominated not by the discovery process per se but by the provision of all the extra data needed to obtain registration. These rising costs happened at a time when markets showed little growth and are currently showing some decline. This has resulted in an industry that is continually striving to cut costs, normally by mergers and take-overs. As a consequence, many plant disease problems are not now being targeted by the industry and special measures have been introduced to ensure adequate disease control is available for these minor markets. Plant disease control will remain a necessity and fungicides will remain as a key factor in such control, although it is predicted that integrated control using chemicals, biological controls and biotechnology approaches will begin to dominate.
The role of fractures and lipids in the seed coat in the loss of hardseededness of six Mediterranean legume species
Authors: ZENG L. W. , COCKS P. S. , KAILIS S. G. , KUO J.
Published: June 2005

Changes in the seed coat morphology of 12 annual legumes were studied using environmental scanning electron microscopy (ESEM). The seeds of Biserrula pelecinus L. cv. Casbah, Ornithopus sativus cv. Cadiz, Trifolium clypeatum L., T. spumosum L., T. subterraneum L. cv. Bacchus Marsh, Trigonella balansae Boiss. & Reuter., Trigonella monspeliaca L. and Vicia sativa subsp. amphicarpa Dorthes (morthes.) were examined by ESEM after exposure to field conditions for 6 months, while those of Medicago polymorpha L. cv. Circle Valley, Trifolium clypeatum L., T. glanduliferum Boiss., T. lappaceum L., T. spumosum L., and T. subterraneum L. cv. Dalkeith, were examined after 2 years' exposure. The entry of water into seeds was followed by covering various parts of the seed coat with petroleum jelly and soaking the treated seeds in dyes.

As the seeds softened over time, more and larger fractures appeared on the seed coat. Water entered the seed either through fractures, over the seed coat as a whole or through the lens. It is hypothesized that the formation of fractures occurs after physicochemical changes in the seed coat, probably associated with changes in the amount and nature of seed coat lipids.

The newly matured whole seeds of M. polymorpha cv. Circle Valley, T. clypeatum, T. glanduliferum, T. lappaceum, T. spumosum, and T. subterraneum cv. Dalkeith were analysed for lipid content in 1997. The seed coats of T. subterraneum cv. Dalkeith and T. spumosum were separated from the cotyledons and examined in detail for lipid content.

The lipid content of whole seeds ranged from 48 (T. lappaceum) to 167 mg/g (T. subterraneum cv. Dalkeith). Total lipid of the whole seeds of T. subterraneum cv. Dalkeith and T. glanduliferum declined by about 9 mg/g over 2 years, while in T. spumosum it declined by about 17 mg/g.

In contrast, the major fatty acids in the seed coat declined by 0·67 mg/g over the 2 years. Change in seed coat lipids showed a marked similarity to changes in hardseededness for both T. subterraneum cv. Dalkeith and T. spumosum. The results strongly suggest that seed softening is associated with loss of lipids in the seed coat, because lipids have physical characteristics that are altered at temperatures experienced in the field.
Explaining contradictory evidence regarding impacts of genetically modified crops in developing countries. Varietal performance of transgenic cotton in India
Authors: BENNETT R. , ISMAEL Y. , MORSE S.
Published: June 2005

A study of the commercial growing of different varieties of Bacillus thuringiensis (Bt) cotton compares the performance of growing official and unofficial hybrid varieties of Bt cotton and conventional (non-Bt) hybrids in Gujarat by 622 farmers. Results suggest that the official Bt varieties (MECH 12 and MECH 162) significantly outperform the unofficial varieties. However, unofficial, locally produced Bt hybrids can also perform significantly better than non-Bt hybrids, although second generation (F2) Bt seed appears to have no yield advantage compared to non-Bt hybrids but can save on insecticide use. Although hybrid vigour is reduced, or even lost, with F2 seed the Bt gene still confers some advantage. The F2 seed is regarded as ‘GM’ by the farmers (and is sold as such), even though its yield performance is little better than the non-GM hybrids. The results help to explain why there is so much confusion arising from GM cotton release in India.
Use of complex phonological patterns in speech processing: evidence from Korean
Authors: WARNER NATASHA , KIM JEESUN , DAVIS CHRIS , CUTLER ANNE
Published: June 2005

Korean has a very complex phonology, with many interacting alternations. In a coronal-/i/ sequence, depending on the type of phonological boundary present, alternations such as palatalization, nasal insertion, nasal assimilation, coda neutralization, and intervocalic voicing can apply. This paper investigates how the phonological patterns of Korean affect processing of morphemes and words. Past research on languages such as English, German, Dutch, and Finnish has shown that listeners exploit syllable structure constraints in processing speech and segmenting it into words. The current study shows that in parsing speech, listeners also use much more complex patterns that relate the surface phonological string to various boundaries.
Characterization of an extracellular serine protease ofLeishmania (Leishmania) amazonensis
Authors: da SILVA-LOPEZ R. E. , PINTO COELHO M. G. , De SIMONE S. G.
Published: June 2005

A serine protease was purified 942-fold from culture supernatant ofL. amazonensispromastigotes using (NH4)2SO4precipitation followed by affinity chromatography on aprotinin-agarose and continuous elution electrophoresis by Prep Cell, yielding a total recovery of 61%. The molecular mass of the active enzyme estimated by SDS-PAGE under conditions of reduction was 56 kDa and 115 kDa under conditions of non-reduction, suggesting that the protease is a dimeric protein. Additionally, it was found to be a non-glycosylated enzyme, with a pI of 5·0. The optimal pH and temperature of the enzyme were 7·5 and 28 °C respectively, using α-N-ρ-tosyl-L-arginine-methyl ester (L-TAME) as substrate. Assays of thermal stability indicated that 61% of the enzyme activity was preserved after 1 h of pre-treatment at 42 °C. Haemoglobin, bovine serum albumin (BSA), ovalbumin, fibrinogen, collagen, gelatin and peptide substrates containing arginine in an ester bond and amide substrates containing hydrophobic residues at the P1 site were hydrolysed by this extracellular protease. The insulin β-chain was also hydrolysed by the enzyme and many peptidic bonds were susceptible to the protease action, and 4 of them (L11-V12, E13-A14, L15-Y16and Y16-L17) were identified. Inhibition studies suggested that the enzyme belongs to the serine protease class inhibited by calcium and manganese and activated by zinc. These findings show that this enzyme ofL. amazonensisis a novel serine protease, which differs from all known flagellate proteases characterized.
The proteasome inhibitor MLN-273 blocks exoerythrocytic and erythrocytic development of Plasmodium parasites
Authors: LINDENTHAL C. , WEICH N. , CHIA Y.-S. , HEUSSLER V. , KLINKERT M.-Q.
Published: June 2005

Protein degradation is regulated during the cell cycle of all eukaryotic cells and is mediated by the ubiquitin-proteasome pathway. Potent and specific peptide-derived inhibitors of the 20S proteasome have been developed recently as anti-cancer agents, based on their ability to induce apoptosis in rapidly dividing cells. Here, we tested a novel small molecule dipeptidyl boronic acid proteasome inhibitor, named MLN-273 on blood and liver stages of Plasmodium species, both of which undergo active replication, probably requiring extensive proteasome activity. The inhibitor blocked Plasmodium falciparum erythrocytic development at an early ring stage as well as P. berghei exoerythrocytic progression to schizonts. Importantly, neither uninfected erythrocytes nor hepatocytes were affected by the drug. MLN-273 caused an overall reduction in protein degradation in P. falciparum, as demonstrated by immunoblots using anti-ubiquitin antibodies to label ubiquitin-tagged protein conjugates. This led us to conclude that the target of the drug was the parasite proteasome. The fact that proteasome inhibitors are presently used as anti-cancer drugs in humans forms a solid basis for further development and makes them potentially attractive drugs also for malaria chemotherapy.
Anomalous winter hydroxyl temperatures at 69°S during 2002 in a multiyear context
Authors: French W. John R. , Burns Gary B. , Espy Patrick J.
Published: June 2005

Hydroxyl airglow temperatures measured over Davis station, Antarctica (68°S, 78°E) in 2002 are compared to an 8‐year climatological mean. The 2002 winter average temperature was 5.1 ± 0.8K warmer than the climatological mean. This anomaly is a factor of two larger than what can be attributed to solar flux increases. Of the 210 nightly averages obtained, 72 (34%) exceeded the climatological maximum, primarily in two unusually warm intervals in late‐May to early‐June and in mid‐July. An unusually cold interval (10 nights below the climatological minimum) coincided with a climatological dip in mid‐August. Temperature oscillations of 15–20 K amplitude, extending over 4 cycles across the Sep–Oct stratospheric warming correlate with Rothera temperatures and Davis mesospheric winds and are consistent with a 14‐day westward propagating zonal planetary wave number 1.
Global observations of energetic electrons around the time of a substorm on 27 August 2001
Authors: Blake J. B. , Mueller‐Mellin R. , Davies J. A. , Li X. , Baker D. N.
Published: June 2005

The magnetospheric substorm that occurred shortly after 04:00 UT on 27 August 2001 has been a topic of detailed study (Baker et al., 2002; Li et al., 2003). These studies included analysis of data from energetic electron detectors aboard the Cluster and Polar spacecraft that were located in the magnetotail during the substorm. Serendipitously, Chandra, the X‐ray observatory, also carrying an energetic electron detector, was located in the magnetotail several hours earlier in local time. Examination of data from the three magnetotail positions revealed that enegetic electrons (>35 keV) appeared simultaneously at all three locations, and that the appearance was ten minutes after the injection into geostationary orbit (GEO) as determine by examination of drift dispersion at several local times in GEO orbit. In addition to the substorm‐associated electrons, time‐correlated electron bursts were observed by the magnetotail spacecraft for a few hours prior to the substorm.
Electrical conductivity of magma in the course of crystallization controlled by their residual liquid composition
Authors: Gaillard F. , Marziano G. Iacono
Published: June 2005

The electrical conductivity of a magma in the course of crystallization was experimentally investigated in the temperature range of 1350–1018°C. Large samples of basaltic composition with a homogeneous crystal content were synthesized in a gas mixing furnace at 1 atm pressure. The samples were analyzed by electron microprobe. The relative proportions of the phases as a function of temperature were determined. Depending on temperature, the phase assemblies included quenched silicate liquid, ±plagioclase, ±pyroxene, ±Fe‐Ti oxides. The crystal content varied from 0 to 80 wt %. In response to partial crystallization, the residual liquid changed composition from basalt, to andesite, to dacite liquid. The electrical conductivity of the partially crystallized basaltic samples was measured. In addition, above liquidus conductivity measurements were conducted on compositions matching the residual liquid at different temperature. These supplemental electrical measurements allowed us to discriminate the effect of crystal content from the effect of changing liquid composition associated with partial crystallization. Combining with the modified Archie's law a set of constraints describing the conductivity of the residual liquid versus chemical composition and temperature, we propose an equation to calculate changes in conductivity associated with partial magma crystallization. We showed how the composition of the residual liquid is critical on the electrical behavior of crystal‐liquid system. The model overcomes the previous difficulties in finding a robust model for describing the electrical behavior of crystal‐liquid systems. The effect of liquid composition on the electrical conductivity is related to diffusion mechanisms and transport properties in molten silicate. Combining known constraints on Na tracer diffusion and our conductivity results confirms the statements that sodium is the dominant charge carrier silicate liquids from basalt to rhyolite. These findings revealed that we need a comprehensive model that can predict the conductivity of molten silicate as a function of chemical composition.
Detailed structure and sharpness of upper mantle discontinuities in the Tonga subduction zone from regional broadband arrays
Authors: Tibi Rigobert , Wiens Douglas A.
Published: June 2005

Recordings of deep Tonga earthquakes from two arrays of 12 broadband seismographs each in the Fiji and Tonga islands are stacked and searched for reflections and conversions from upper mantle discontinuities in the Tonga subduction zone. The arrays operated as part of the Seismic Arrays in Fiji and Tonga (SAFT) experiment from July 2001 to August 2002. In comparison with the commonly used teleseismic approaches, the short path lengths for the local data provide smaller Fresnel zones and high‐frequency content for precise mapping of discontinuity topography and sharpness. To enhance the low‐amplitude discontinuity phases s410p, P660p and S660p, deconvolved seismograms from each event/array pair are aligned on the maximum amplitude of the direct P wave and subsequently slant stacked. For the 410‐km discontinuity, the results show no systematic variations in depth with distance to the cold slab. The 660‐km discontinuity varies between 656 and 714 km in depth. For the southern and central parts of the subduction zone, the largest depths occur in the core of the Tonga slab. For the northern part, two separate depressions of the 660‐km discontinuity are observed. These anomalies are interpreted as being induced by the active, steeply subducting Tonga deep zone and a subhorizontally lying remnant of subducted lithosphere from the fossil Vityaz trench, respectively. Interpreting the deflections of the 660‐km discontinuity in terms of local temperatures implies a thermal anomaly of −800°K to −1200°K at 660 km depth. Except for the southern region where it may thicken, the width of the depressed 660‐km discontinuity region implies that the Tonga slab seems to penetrate the 660‐km discontinuity with little deformation. Waveform modeling suggests that both the 410‐ and 660‐km discontinuities are sharp. The 660‐km discontinuity is at most 2 km thick in many parts of the region, and a first‐order discontinuity cannot be precluded. The 410‐km discontinuity thickness shows somewhat more variability and ranges from 2 to 10 km outside the slab and is at most 10 km thick within the slab. This suggests that the subduction process does not produce dramatic effects on the sharpness of the discontinuities.
Characteristics and origin of lowermost stratospheric aerosol at northern midlatitudes under volcanically quiescent conditions based on CARIBIC observations
Authors: Martinsson Bengt G. , Nguyen Hung N. , Brenninkmeijer Carl A. M. , Zahn Andreas , Heintzenberg Jost , Hermann Markus , van Velthoven Peter F. J.
Published: June 2005

Characteristics and origin of the aerosol in the lowermost stratosphere at northern midlatitudes were studied using measurements from a passenger aircraft (Civil Aircraft for Regular Investigation of the Atmosphere Based on an Instrument Container, or CARIBIC). Aerosol samples were collected during 60 intercontinental flights during 1999–2002 and analyzed for elemental composition with particle‐induced X‐ray emission (PIXE). Concurrent measurements of trace gases were used to interpret the aerosol measurements. It was found that particulate sulfur concentration increased steadily in the potential vorticity (PV) region of 2–7 PVU, whereas particulate potassium and iron showed no such dependence. The variability in concentration of the latter two elements was mainly connected with season, similar to their variation in the upper troposphere, whereas PV dominated the particulate sulfur variability. An ozone‐based model was developed to quantitatively determine the mixing of stratospheric and tropospheric air masses. A significant dependence on PV was found, and the stratospheric fraction of the air peaked during spring. It was found that the particulate sulfur concentration was strongly dependent on the origin of the air masses. The concentration increased by a factor of 3 over the lowermost stratosphere. A discontinuity in the concentration over the tropopause indicated particle formation from sulfur dioxide transported across the tropopause. The concentration at the top of the lowermost stratosphere was used to estimate that the particulate sulfur production in the stratosphere is 0.066 Tg S/yr with approximately half of the amount transported across the top of the lowermost stratosphere originating in carbonyl sulfide.
Holocene and deglacial ocean temperature variability in the Benguela upwelling region: Implications for low‐latitude atmospheric circulation
Authors: Farmer E. Christa , deMenocal Peter B. , Marchitto Thomas M.
Published: June 2005

Mg/Ca analyses of G. bulloides and abundances of N. pachyderma (left coiling) from Ocean Drilling Program (ODP) Leg 175 Hole 1084B in the Benguela coastal upwelling system document lower sea surface temperatures during the Last Glacial Maximum (LGM), Younger Dryas, mid‐Holocene, and Little Ice Age in the southeastern Atlantic. Taking into consideration the possible effects of differential carbonate dissolution, the Mg/Ca data indicate Younger Dryas temperatures 2°–3°C cooler than those of the early Holocene and LGM temperatures 4°–5°C cooler than those of the early Holocene. The cool interval during the deglacial period at Hole 1084B matches the timing of Younger Dryas shifts in Cariaco Basin and Greenland Ice Sheet records and that of a nearby alkenone record. Comparison of mid‐Holocene cooling at Hole ODP1084B with other high‐resolution records of Holocene and last deglacial sea surface temperatures from the tropical Atlantic implies consistent basin‐wide changes in atmospheric circulation. A brief period of 1.5°–2°C cooling between 17.8 and 17.2 ka, if related to Heinrich event 1, is consistent with a previously hypothesized tropical origin of all Heinrich climate change events.
Aquitard effect on drawdown in water table aquifers
Authors: Zlotnik Vitaly A. , Zhan Hongbin
Published: June 2005

The effects of an aquitard on drawdown in an overlying unconfined aquifer can be represented by a drainage‐type term at the aquitard‐aquifer interface. The functional form of this boundary condition is similar to the Boulton‐Neuman boundary condition used for water table aquifers except the kernel contains an inverse square root of time instead of a negative exponential. Type curves using the new boundary condition were obtained in semianalytical form. Examples for several representative conditions show that the effect of the underlying aquitard can contribute to the type curve at early and intermediate times, but the effect becomes negligible at late times.
A geomorphic study of lagoonal landforms
Authors: Feola Alessandra , Belluco Enrica , D'Alpaos Andrea , Lanzoni Stefano , Marani Marco , Rinaldo Andrea
Published: June 2005

We perform an analysis of the observational morphological structure of a tidal landscape aimed at examining key assumptions on the geomorphological evolution of wetlands, lagoons, estuarine areas and tidal environments in general. The issues addressed pertain to the statistical measures and the morphodynamic implications of topological or metric properties of the observed landforms, in particular their scale‐dependent (or invariant) characters that might suggest self‐organized dynamical origins. Field surveys and remote sensing are employed here to accurately characterize different morphodynamic features of a lagoonal environment. Of particular novelty and interest is the structure of landscape‐forming shear stresses (properly calculated in unchanneled portions of the landscape) which suggests the viability of threshold models of incision for the formation of tidal channel networks. Distinctive geomorphic indicators, suitable for comparative purposes with modeling of the long‐term evolution of tidal systems, are also pointed out. We finally discuss space‐distributed analyses of ecogeomorphological properties which strongly suggest the dominance of subvertical processes in the control of the distribution of halophytic vegetation, a key morphodynamic factor.
Quasi thermal noise spectroscopy in the inner magnetosphere of Saturn with Cassini/RPWS: Electron temperatures and density
Authors: Moncuquet Michel , Lecacheux Alain , Meyer‐Vernet Nicole , Cecconi Baptiste , Kurth William S.
Published: June 2005

On 1 July 2004, the Cassini spacecraft performed its Saturn orbit insertion, twice crossing the equatorial plane between the G and F rings. The radio HF receiver observed a peak at the upper‐hybrid frequency and weakly banded emissions having well‐defined minima at gyroharmonics. We show that through most of the encounter, these emissions do not result from instabilities, but instead are the quasi‐thermal noise that can be calculated from the classical theory of plasma fluctuations. The spectroscopy of this noise yields the electron density, the core and the halo temperatures in the range 2.3 < L/RS < 7, −1.2 < z/RS < +0.1. For the first time, we measure the core temperature of the Kronian plasma torus to be about 0.5 eV in the ring plane at ∼2.5RS, and increasing to ∼6 eV at 7RS. From the noise minima at the gyroharmonics, we also deduce the magnetic field strength, which agrees with the Cassini's magnetometer data to better than 2%.
Polar processing and development of the 2004 Antarctic ozone hole: First results from MLS on Aura
Authors: Santee M. L. , Manney G. L. , Livesey N. J. , Froidevaux L. , MacKenzie I. A. , Pumphrey H. C. , Read W. G. , Schwartz M. J. , Waters J. W. , Harwood R. S.
Published: June 2005

The Microwave Limb Sounder (MLS) on Aura is providing an extensive data set on stratospheric winter polar processing, including the first daily global observations of HCl, together with simultaneous measurements of ClO, HNO3, H2O, O3, N2O, and temperature (among others). We present first results charting the evolution of these quantities during the 2004 Antarctic late winter. MLS observations of chlorine deactivation and ozone loss during this period are shown to be consistent with results from the SLIMCAT chemical transport model.
Velocity and scaling of collapsing Euler vortices
Authors: Kerr Robert M.
Published: June 2005

New analysis of the scaling structure of a numerical solution of the Euler equations finds that initially antiparallel vortex tubes collapse into two wings whose cross sections can be described using two length scales ρ and R. The first ρ∼(T−t) for the leading edge and the distance between the position of peak vorticity and the dividing plane. The second R∼(T−t)1∕2 describes the extent of the wings and the distance of the peak in vortical velocity supx∣v∣ from the peak in vorticity. All measures of singular growth within the inner region give the same singular time. This includes a blowup in the peak of vortical or axial velocity going as (T−t)−1∕2 at a distance R from the position of ∥ω∥∞. Outside this self-similar region, energy, enstrophy, circulation, and helicity accumulate. Twisting of vortex lines consistent with vortex line length growing to infinity is observed in the outer region. Vorticity in the intermediate zone between the inner and outer regions, while no longer growing at the singular rate, could be the major source of the strain interactions that drive the flow.
A numerical procedure for simulating the behavior of multimode, bolometric, astronomical interferometers
Authors: Withington Stafford , Campbell Edward S. , Hobson Michael P.
Published: June 2005

A procedure is described for simulating the behavior of multimode, bolometric, astronomical interferometers. The procedure relies on the use of singular value decomposition to determine the fields on the sky and the fields at the detectors to which the individual elements of an interferometer can couple. The scheme can be used with any configuration of optical components, with a source in any state of coherence, and with a detector of any kind: planar bolometers, waveguide horns, imaging arrays, etc. In the paper we describe the space-domain formulation of the theory, and present simulations of classical Fizeau and Michelson interferometers. We also show that the scheme reproduces correctly the behavior of single-mode radio and highly multimode optical interferometers when the appropriate limits are taken. To conclude, we discuss the many different ways in which the basic technique can be used and extended.
Experimental and theoretical studies of rate coefficients for the reaction O(P3)+CH3OH at high temperatures
Authors: Lu Chih-Wei , Chou Shen-Long , Lee Yuan-Pern , Xu Shucheng , Xu Z. F. , Lin M. C.
Published: June 2005

Rate coefficients of the reaction O(P3)+CH3OH in the temperature range of 835–1777K were determined using a diaphragmless shock tube. O atoms were generated by photolysis of SO2 with a KrF excimer laser at 248nm or an ArF excimer laser at 193nm; their concentrations were monitored via atomic resonance absorption excited by emission from a microwave-discharged mixture of O2 and He. The rate coefficients determined for the temperature range can be represented by the Arrhenius equation, k(T)=(2.29±0.18)×10−10exp[−(4210±100)∕T]cm3molecule−1s−1; unless otherwise noted, all the listed errors represent one standard deviation in fitting. Combination of these and previous data at lower temperature shows a non-Arrhenius behavior described as the three-parameter equation, k(T)=(2.74±0.07)×10−18T2.25±0.13exp[−(1500±90)∕T]cm3molecule−1s−1. Theoretical calculations at the Becke-3-Lee–Yang–Parr (B3LYP)∕6−311+G(3df,2p) level locate three transition states. Based on the energies computed with coupled clusters singles, doubles (triples) [CCSD(T)]/6−311+G(3df,2p)∕∕B3LYP∕6−311+G(3df,2p), the rate coefficients predicted with canonical variational transition state theory with small curvature tunneling corrections agree satisfactorily with the experimental observations. The branching ratios of two accessible reaction channels forming OH+CH2OH (1a) and OH+CH3O (1b) are predicted to vary strongly with temperature. At 300K, reaction (1a) dominates, whereas reaction (1b) becomes more important than reaction (1a) above 1700K.
Tuning the surface-plasmon resonance in nanoparticles for glazing applications
Authors: Schelm S. , Smith G. B. , Garrett P. D. , Fisher W. K.
Published: June 2005

Issues affecting the performance of polymers doped with conducting nanoparticles for use with windows are examined in terms of impact on visible and solar transmittance, solar heat gain, and residual scattering. Emphasis is on visible transmittance fixed in the range of 30%–75%, combined with maximal blocking of the near-infrared (NIR) component of solar energy in the wavelength range of 750–1300nm. Spectral data and surface-plasmon resonance (SPR) models of absorbance for LaB6 and indium tin oxide nanoparticles embedded in polymer are quite distinct from each other, but both can be used and each material has its advantages and disadvantages. The SPR of LaB6 nanoparticles is very efficient at NIR blocking, as it lies near 1000nm, but as a result its tail overlaps the visible. In contrast the SPR of ITO lies well beyond 1000nm and is thus far less efficient, only relying on its SPR tail. However, this means it only weakly affects the visible. Results of a quasistatic model for the optical properties are presented, along with comparisons to full Mie scattering calculations. It is found that ellipsoidal particles are required to explain the properties of the studied LaB6 particles, and that scattering can be significant in the NIR while weak in the visible. Furthermore, the forward-to-backward-scattering ratio is different for Rayleigh scattering in the visible and scattering near the SPR. The latter is much more isotropic, even for larger particles.
A high-frequency electrospray driven by gas volume charges
Authors: Lastochkin Dmitri , Chang Hsueh-Chia
Published: June 2005

High-frequency (>10kHz) ac electrospray is shown to eject volatile dielectric liquid drops by an entirely different mechanism from dc sprays. The steady dc Taylor conic tip is absent and continuous spraying of submicron drops is replaced by individual dynamic pinchoff events involving the entire drop. We attribute this spraying mechanism to a normal Maxwell force produced by an undispersed plasma cloud in front of the meniscus that produces a visible glow at the spherical tip. The volume charge within the cloud is formed by electron-induced gas ionization of the evaporated liquid and produces a large normal field that is much higher than the nominal applied field such that drop ejection occurs at a voltage (at high frequencies) that is as much as ten times lower than that for dc sprays. The ejection force is sensitive to the liquid properties (but not its electrolyte composition), the ac frequency and trace amounts of inert gases, which are believed to catalyze the ionization reactions. As electroneutral drops are ejected, due to the large (>100) ratio between individual drop ejection time and the ac frequency, this mechanism can produce large (microns) electroneutral drops at relatively low voltages.