bluuebunny/crossref_metadata_2025 huggingface dataset:
A novel calcium‐dependent soluble inorganic pyrophosphatase from the trypanosomatid Leishmania major
Authors: Gómez-Garcı́a Marı́a R , Ruiz-Pérez Luis M , González-Pacanowska Dolores , Serrano Aurelio
Published: February 2004

A single‐copy gene IPP encoding a putative soluble inorganic pyrophosphatase (LmsPPase, EC 3.6.1.1) was identified in the genome of the parasite protozoan Leishmania major. The full‐length coding sequence (ca. 0.8 kb) was obtained from genomic DNA by polymerase chain reaction (PCR) and cloned into an Escherichia coli expression vector, and was overexpressed for functional protein purification and characterization. The recombinant LmsPPase, purified to electrophoretic homogeneity by a two‐step chromatography procedure, exhibited a predicted molecular mass of ca. 30 kDa. The enzyme has an absolute requirement for divalent cations, exhibits a pH optimum of 7.5–8.0 and does not hydrolyze polyphosphates or adenosine triphosphate (ATP). LmsPPase differs from previously studied soluble pyrophosphatases with respect to cation selectivity, Ca2+ being far more effective than Mg2+. Comparisons to known sPPases show a short N‐terminal extension predicted to be a mitochondrial transit peptide, and changes in active‐site residues and the neighboring region. Subcellular fractionation of L. major promastigotes suggests a mitochondrial localization. Molecular phylogenetic analysis indicates that LmsPPase is a highly divergent eukaryotic Family I sPPase, perhaps an ancestral class of eukaryotic sPPases functionally adapted to a calcium‐rich, probably mitochondrial, environment.
Late Neoproterozoic to Early Palaeozoic palaeogeography of Avalonia: some palaeomagnetic constraints from Nuneaton, central England
Authors: VIZAN HAROLDO , CARNEY JOHN N. , TURNER PETER , IXER ROBERT A. , TOMASSO MARK , MULLEN ROBERT P. , CLARKE PAUL
Published: February 2004

Palaeomagnetic studies have been carried out on Neoproterozoic, Cambrian and Ordovician rocks in the Nuneaton inlier, England (52.5° N, 1.5° W). Three magnetic components were recognized, which provide a consistent structural and magnetic history of the inlier. Neoproterozoic volcaniclastic and intrusive rocks acquired a characteristic remanent magnetization (ChRM) dated at 603Ma. Late Ordovician rocks are represented by lamprophyre and diorite intrusions and their ChRMs were probably imprinted during their emplacement, at about 442 Ma. The Lower Cambrian sedimentary sequence of the Hartshill Sandstone Formation, which unconformably overlies the Neoproterozoic rocks and hosts the Ordovician intrusions, does not preserve a primary magnetization but shows the imprints of the Late Ordovician (442 Ma) remagnetization, as well as a probable end-Carboniferous remagnetization. Palaeolatitudes calculated for the late Neoproterozoic rocks and Ordovician intrusions are in good agreement with other palaeolatitudes calculated for Avalonia during those times. Both the late Neoproterozoic and Late Ordovician rocks additionally show ChRMs with declination anomalies indicating a large tectonic rotation of the Nuneaton area, possibly during one of the Caledonian phases of deformation affecting southern Britain.
New Psocoptera in the Early Cretaceous amber of SW France and Lebanon (Insecta: Psocoptera: Trogiomorpha)
Authors: PERRICHOT VINCENT , AZAR DANY , NERAUDEAU DIDIER , NEL ANDRE
Published: February 2004

Proprionoglarisguyoti gen. nov., sp. nov., Parapsyllipsocus vergereaui gen. nov., sp. nov., and Prospeleketoralbianensis gen. nov., sp. nov. are described from the Early Cretaceous amber of Archingeay (SW France). Libanoglarismouawadi gen. nov., sp. nov. is described from the Early Cretaceous amber of Lebanon. They are all placed into the suborder Trogiomorpha, incertae familiae. The discovery of these new taxa together with a first phylogenetic analysis of the trogiomorphan families demonstrate the necessity of a cladistic redefinition of the currently admitted major subdivisions of this suborder.
The lost Lower Old Red Sandstone of England and Wales: a record of post-Iapetan flexure or Early Devonian transtension?
Authors: SOPER N. J. , WOODCOCK N. H.
Published: February 2004

Illite crystallinity data from the Silurian slate belts of England and Wales indicate anchizone to low epizone metamorphism during the Acadian deformation in late Early Devonian time. This metamorphic grade implies a substantial overburden, now eroded, of Lower Devonian non-marine sediments of the Old Red Sandstone (ORS) magnafacies. A minimum 3.5 km pre-tectonic thickness of ‘lost’ ORS is estimated in the southern Lake District and comparable thicknesses in North Wales and East Anglia. Tectonically driven subsidence of the underlying Avalonian crust is required to accommodate such thicknesses of non-marine sediment. One proposed mechanism is flexure of the Avalonian footwall during convergence that continued from Iapetus closure in the Silurian until Acadian cleavage formation in the Emsian. The evidence for this model in the critical area of northwest England is reviewed and found to be unconvincing. An alternative model is developed following a recent suggestion that the Early Devonian was a period not of continued convergence but of orogen-wide sinistral transtension. Transtensional accommodation of the lost ORS is evidenced by Early Devonian extensional faults, by synchronous lamprophyric magmatism, and by compatibility with previously diagnosed sediment provenance patterns. A summary of Siluro-Devonian tectonostratigraphy for Britain south of the Highland Border emphasizes that, unlike the Scottish Highlands, this area was not affected by the Scandian Orogeny, but was by the Acadian. An important period of sinistral transtension in the Early Devonian (c.420–400 Ma) was common to both regions. This was a time of high heat flow, lamprophyric and more evolved magmatism, and major southward sediment transport, involving mainly recycled metamorphic detritus from the Highlands and from contemporaneous volcanicity. Old Red Sandstone, deposited in coalescing transtensional basins over much of Britain from the Midland Valley to the Welsh Borders, was largely removed and recycled southward during Acadian inversion.
RECALL OF SCHEMATIC AND NON-SCHEMATIC MATERIAL RELATED TO THREAT IN SOCIALLY ANXIOUS AND NONANXIOUS INDIVIDUALS
Authors: Wenzel Amy , Haugen Erin N. , Schmutzer Peter A.
Published: February 2004

The present study examined the recall of material representative and non representative of schemata for social and evaluative situations. Socially anxious (n = 24) and nonanxious (n = 25) individuals were presented with three positively valenced and three negatively valenced prose passages describing common social and evaluative scenarios. Eight of the sentences in each passage described events representative of the schema content of most individuals, whereas three of the sentences in each passage described events that are not representative of typical schema content. Participants completed a free recall task in both immediate (i.e. 2 minutes) and delayed (i.e. one week) recall conditions. Although there were no group differences as a function of type of content (i.e. schematic, non-schematic), socially anxious individuals were less likely than nonanxious individuals to accurately recall the gist of passages containing negative information in the immediate recall condition. In all, this study provided little evidence for the influence of maladaptive schema content on memory for threatening material in anxious individuals, but it added to an increasingly large literature suggesting that some types of anxiety are associated with an avoidance of processing emotional material.
AN INVESTIGATION OF THE FACTOR STRUCTURE OF THE NOVACO ANGER SCALE
Authors: Jones Jason , Thomas-Peter Brian , Gangstad Berit
Published: February 2004

The Novaco Anger Scale is the only scale published that allows for the measurement of anger with relation to Novaco's (1976) widely used model of anger management. This paper is the first to present a statistical analysis of the factor structure of this scale. From a sample of healthcare employees and outpatients with problems with anger control, a factor solution was identified. It is suggested that the items loading on this scale contribute to valid assessment of anger. The implications for the use of the NAS are considered.
PREVENTING PTSD: THE VALUE OF INNER RESOURCEFULNESS AND A SENSE OF PERSONAL CONTROL OF A SITUATION. IS IT A MATTER OF PROBLEM-SOLVING OR ANXIETY MANAGEMENT?
Authors: Ness Graham J. , Macaskill Norman
Published: February 2004

The accounts of five subjects who survived life threatening experiences without the development of PTSD were examined, focusing on the coping strategies and cognitions described in these situations. The study aimed to determine whether there was a common pattern of response amongst subjects in these situations similar to the cognitive patterns described by the senior author of the previous case study (Ness & Macaskill, 2000) who survived a near drowning experience without the development of PTSD. In the search for common coping strategies all five respondents in the study completed the Locus of Control Scale (Rotter, 1966) and the Self-Control Schedule (Fisher & Reason, 1988). All five respondents demonstrated the use of problem solving as their main cognitive strategy, utilizing specific information from their previous experience relevant to their life-threatening situation. Respondents did not appear to rely on coping strategies aimed at the management of acute anxiety symptomatology. There was no common pattern among respondents in profiles on the Self-Control Schedule or the Locus of Control Scale. The possible implications of this case series study are discussed in relation to opportunities for the prevention of PTSD, the use of debriefing and the treatment of post-traumatic stress.
Book Reviews
Authors: Steel Craig
Published: February 2004

If you are interested in reviewing books/texts/materials/software for Behavioural and Cognitive Psychotherapy, then please contact us at the address below, indicating your particular areas of interest and/or title of item to be reviewed. Also, if you would like to recommend a book (new or old) for review, please supply us with the title, author and publisher and we will do our best to obtain it.
Estimating the abundances of large herbivores in the Kruger National Park using presence–absence data
Authors: Tosh Cheryl A. , Reyers Belinda , van Jaarsveld Albert S.
Published: February 2004

Conservation planning and practice rely heavily on abundance information generated at local scales for decision‐making. Unfortunately most distributional data are only provided as presence–absence records at regional or national scales and cannot be used for making local conservation decisions. To date, two methods have been proposed for estimating local abundances and area of occupancy from coarse‐scale presence–absence data. Kunin (1998) proposed the use of the fractal method, which assumes that species distributions are self‐similar across scales. He & Gaston (2000a), in turn, proposed the use of the negative binomial distribution (NBD) for estimating abundances from presence–absence data collected at different scales. Previously only plant data were used to test these models. In the present study, they were tested using distributional presence–absence, as well as abundance data for a selection of large herbivores that have a restricted distribution in the Kruger National Park, South Africa. The results illustrate that the fractal method tends to overestimate areas of occupancy, while the NBD method underestimates the areas of occupancy of all species. This means that there were significant differences between the predictions provided by the two methods. Both these methods rely on the relationship between the area of occupancy and the size of the area over which the survey is conducted, but describe this relationship in a different way. These techniques could prove useful in the field of conservation biology and this study illustrates that these methods can be used on large mammal species and deliver results that are consistent with previous studies on plants.
Priority conservation areas for butterflies (Lepidoptera: Rhopalocera) in the Philippine islands
Authors: Danielsen Finn , Treadaway Colin G.
Published: February 2004

Effective representation of all species in local conservation planning is a major challenge, particularly in poorly known but highly fragmented biological ‘hotspots’. Based on 105 months of studies over 49 years, we reviewed the status of 915 species and 910 subspecies of butterflies known in the Philippines. We identified 133 globally threatened and conservation‐dependent endemic Philippine taxa. The current system of 18 priority protected areas provides at least one protected area for 65 of these but no areas for 29 species and 39 subspecies. Of the 133 taxa, 71% do not have a stable population inside a priority site. A total of 29 taxa is endangered or critically endangered; 83% of these do not occur within a priority site. Least protected are the lowland taxa. The minimum network required to include each threatened and conservation‐dependent taxon of butterfly within at least one area would comprise 29 sites. The Sulus and Mindanao hold disproportionate numbers of threatened butterflies. Our findings suggest limited cross‐taxon congruence in complementarity‐derived priority sets. A large proportion of the priority areas for Philippine butterflies do not coincide with known priority areas for mammals and birds. We demonstrate that a better resolved species level classification could reveal numerous ‘new’ priority areas. In tropical island and mountain regions where the distinctiveness of butterfly subspecies is high, significant evolutionary units may be lost unless fine‐scale conservation planning pays attention to well‐defined subspecies.
The relationship between population size and temporal variability in population size
Authors: Reed David H. , Hobbs Gayla R.
Published: February 2004

The relationship between population size and temporal variability in population size was examined using 2387 populations of 203 species from the Global Population Dynamics Database. Population variability, relative to population size, was assayed by regressing the standard deviation of population size against mean population size. Linear regression produced slopes that were less than one in 165 of 203 species. Thus, temporal fluctuations in population size became significantly weaker as population size increased. Similarly, the slope was significantly less than one for a single regression including all 2387 populations, regardless of taxonomic classification. The slopes of the regression lines did not differ for major taxonomic groupings, but the Y‐intercept was significantly lower for birds than for the other taxonomic groupings. Factor analysis was used to examine the highly correlated parameters: data reliability, population size and taxonomic lineage. Population size was obviously the most important parameter affecting temporal variation in population size, data reliability was also very important, but taxonomy was of little or no importance. The relationship between temporal variation in population size and mean population size, predicted from the data, was used to predict the probability of extinction assuming a normal distribution of population sizes. This simple model predicts that populations of vertebrates will have to number in the thousands for long‐term conservation to be effective.
Zwei Seiten derselben Medaille?
Authors: Höft Stefan , Bolz Christian
Published: February 2004

Zusammenfassung. Die zunehmende Professionalisierung von Eignungsdiagnosen führt dazu, dass die Inhalte ganz unterschiedlicher Verfahrensansätze bei der Entscheidungsfindung miteinander verknüpft werden müssen. Bisher fehlen hierzu in vielen Bereichen schlüssige Konzepte. In der vorliegenden Untersuchung werden die Überschneidungen zwischen eigenschafts- und simulationsorientierten Diagnostika untersucht (Allgemeine Intelligenz, Big Five vs. Anforderungsdimensionen eines Assessment Centers). Hierfür wird zunächst die widersprüchlich erscheinende metaanalytische Befundlage aufgearbeitet. In einer Vorstudie mit Daten von 533 Nachwuchsflugzeugführer-Bewerbern zeigt sich, dass bei dem eingesetzten Persönlichkeitsverfahren (NEO-PI-R) in der vorliegenden Personalauswahlsituation nur eine kleine Anzahl von Big5-Facetten und bestimmte Items verzerrt beantwortet werden. In der Hauptstudie wird anhand der Daten von 128 AC-Absolventen der Zusammenhang zwischen Eigenschaften und Anforderungen auf unterschiedlichen Ebenen (Allgemeine Intelligenz und Big5-Dimensionen und -Facetten vs. verfahrensspezifische Urteile, verfahrensübergreifende Anforderungsurteile, AC-Gesamturteil) überprüft. Allgemeine Intelligenz zeigt einen generell positiven Zusammenhang mit fast allen AC-Variablen inklusive des Gesamturteils. Die Big5-Eigenschaften weisen hingegen speziell auf der Facettenebene erwartungskonform spezifische Beziehungen zu ausgewählten Anforderungen auf. Generell ergeben sich aber deutlich weniger Zusammenhänge als erwartet. Die Konsequenzen für die diagnostische Praxis werden kritisch diskutiert.
Aberrant Sensorimotor Integration in Musicians' Cramp Patients
Authors: Lim Vanessa K. , Bradshaw John L. , Nicholls Michael E.R. , Kirk Ian J. , Hamm Jeff P. , Grossbach Michael , Altenmüller Eckart
Published: February 2004

AbstractSimple tapping and complex movements (Luria finger apposition task) were performed unimanually and bimanually by two groups of professional guitarists while EEG was recorded from electrodes over the sensorimotor cortex. One group had a task-specific movement disorder (focal dystonia or musicians' cramp), while the other group did not (controls). There were no significant group interactions in the task-related power (TRPow) within the alpha range of 8-10Hz (mu1). In contrast, there was a significant group interaction within the alpha range of 10-12Hz (mu2); these latter frequencies are associated with task-specific sensorimotor integration. The significant group interaction included task (simple and complex) by hand (left, right, and both) by electrodes (10 electrodes over the sensorimotor areas). In the rest conditions, the alpha power (10-12Hz) was comparable between the groups; during movement, however, compared to the controls, patients demonstrated the greatest TRPow (10-12Hz) over all conditions. This was particularly evident when patients used their affected hand and suggests that patients with musicians' cramp have impaired task-specific sensorimotor integration.
Connection between Caspian sea level variability and ENSO
Authors: Arpe K. , Bengtsson L. , Golitsyn G. S. , Mokhov I. I. , Semenov V. A. , Sporyshev P. V.
Published: February 2004

The problem of the world greatest lake, the Caspian Sea, level changes attracts the increased attention due to its environmental consequences and unique natural characteristics. Despite the huge number of studies aimed to explain the reasons of the sea level variations the underlying mechanism has not yet been clarified. The important question is to what extent the CSL variability is linked to changes in the global climate system and to what extent it can be explained by internal natural variations in the Caspian regional hydrological system. In this study an evidence of a link between the El Niño/Southern Oscillation phenomenon and changes of the Caspian Sea level is presented. This link was also found to be dominating in numerical experiments with the ECHAM4 atmospheric general circulation model on the 20th century climate.
Contribution of salt‐fingering to the conveyor belt circulation in the abyssal northern Indian Ocean
Authors: You Yuzhu
Published: February 2004

The abyssal northern Indian Ocean shows relatively high temperature and salinity. Previous study ofYou(Deep‐Sea Research I, 46, 109–148, 1999) demonstrated that this is due to salt‐fingering which brings salt and heat from the upper layer to the depth. However, conveyor belt circulation requires upwelling there. This study further demonstrates that whilst salt‐fingering brings salt and heat to the abyssal water, the processes concurrently result in upward dianeutral motion. Therefore, it is consistent with the conveyor belt circulation.
Oxygen auger electrons observed in Mars' ionosphere
Authors: Mitchell D. L. , Lin R. P. , Rème H. , Crider D. H. , Cloutier P. A. , Connerney J. E. P. , Acuña M. H. , Ness N. F.
Published: February 2004

Over the course of 290 orbits, the Electron Reflectometer onboard Mars Global Surveyor consistently observed a plasma boundary at a median altitude of 380 km, where electron fluxes at energies greater than ∼100 eV change abruptly by about an order of magnitude. Above the boundary, electron energy spectra are consistent with solar wind electrons that have been shocked and then cooled by impact with exospheric neutrals. Below the boundary, electron energy spectra exhibit a broad feature from 20 to 50 eV, which likely results from a blend of unresolved photoionization peaks that have been predicted by published models of ionospheric photoelectrons at Mars. We attribute a second feature at ∼500 eV to oxygen Auger electrons. The 500‐eV flux level measured below the boundary responds to variations in the solar soft x‐ray flux and is consistent with a balance between photoionization and loss by impact with atmospheric neutral atoms.
Abrupt changes in meteorological conditions observed at an inland Antarctic Station in association with wintertime blocking
Authors: Hirasawa Naohiko , Nakamura Hisashi , Yamanouchi Takashi
Published: February 2004

Time evolution of a prominent wintertime blocking event over East Antarctica and the associated drastic changes in weather conditions observed at an inland station are documented. A strong blocking ridge was formed at the leading edge of a quasi‐stationary Rossby wavetrain where a wave activity flux emanating from the subtropics was convergent. The ridge pumped up heat and moisture from lower latitudes into inland Antarctica with a strong poleward flow along its upstream flank. The station was situated under this flow just for two days, during which the normal condition with cold and clear weather was markedly disturbed. The flow climbing up the continental slope led to cloud formation above the inland station. Enhanced downward longwave radiation from the clouds and enhanced vertical mixing associated with the record‐setting wind speeds resulted in a sudden, drastic increase in surface air temperature and the breakdown of the developed surface inversion layer.
An eigen analysis of the interdecadal changes in the structure and frequency of ENSO mode
Authors: An Soon‐Il , Jin Fei‐Fei
Published: February 2004

The mechanisms of interdecadal changes of El Niño‐Southern Oscillation (ENSO) modes are examined through an eigen analysis of a simple coupled ocean‐atmosphere model. It is shown that the observed interdecadal climate shift can effectively modify the strength of two major coupled feedbacks for the ENSO mode, namely, the zonal advection and thermocline feedbacks. These modifications lead to quantitative changes of the leading coupled mode in its frequency, growth rate, and spatial pattern, which are consistent with the observation.
The effect of upper ocean eddies on the non‐steric contribution to the barotropic mode
Authors: Shriver Jay F. , Hurlburt Harley E.
Published: February 2004

The non‐steric contribution to sea surface height (SSH) variability hampers the use of satellite altimeter data in mapping steric‐related variability. Here, two eddy‐resolving 1/16° world ocean simulations are used to investigate the effects of mesoscale flow instabilities on the non‐steric (or abyssal ocean) contribution to the global barotropic mode. Model results show the non‐steric component accounting for >50% of the total SSH variability over 37% of the world ocean in the model, predominantly at mid and high latitudes. Most of this is either wind‐driven and deterministic or eddy‐driven and nondeterministic. Upper ocean flow instabilities drive deep flows and generate non‐steric SSH variability maxima (5–10 cm rms or more) in many major current systems throughout the world ocean. Resulting ocean anomalies are a nondeterministic response to atmospheric forcing and an eddy‐resolving data‐assimilative ocean model that demonstrates the essential dynamics is needed to depict their evolution.
Influence of the aerosol vertical distribution on the retrievals of aerosol optical depth from satellite radiance measurements
Authors: Quijano Ana Lía , Sokolik Irina N. , Toon Owen B.
Published: February 2004

We investigate the importance of the layered vertical distribution of absorbing and non‐absorbing tropospheric aerosols for the retrieval of the aerosol optical depth from satellite radiances measured at visible wavelengths at a single viewing angle. We employ lidar and in‐situ measurements of aerosol extinction coefficients and optical depths to model radiances which would have been observed by a satellite. Then, we determine the aerosol optical depth that would produce the observed radiance under various sets of assumptions which are often used in current retrieval algorithms. We demonstrate that, in the presence of dust or other absorbing aerosols, the retrieved aerosol optical depth can underestimate or overestimate the observed optical depth by a factor of two or more depending on the choice of an aerosol optical model and the relative position of different aerosol layers. The presence of undetected clouds provides a further complication.
Scaling of fracture connectivity in geological formations
Authors: Berkowitz Brian , Bour Olivier , Davy Philippe , Odling Noelle
Published: February 2004

A new method to quantify fracture network connectivity is developed and applied to analyze two classical examples of fault and joint networks in natural geological formations. The connectivity measure accounts for the scaling properties of fracture networks, which are controlled by the power law length distribution exponent a, the fractal dimension D and the fracture density. The connectivity behavior of fracture patterns depends on the scale of measurement, for a < D + 1, but is independent of scale for a > D + 1. Analysis of the San Andreas fault system shows that a < D+1 and that the connectivity threshold is reached only at a critical length scale. In contrast, for a typical sandstone joint pattern, a ≈ D + 1, which is on the cusp where the connectivity threshold is highly sensitive to the minimum fracture length in the system.
The transition from the Last Glacial Period in inland and near‐coastal Antarctica
Authors: Mulvaney R. , Röthlisberger R. , Wolff E. W. , Sommer S. , Schwander J. , Hutterli M. A. , Jouzel J.
Published: February 2004

Recent studies suggested that, during the transition out of the last glacial period, one near‐coastal site in Antarctica showed a response similar to that of Greenland, and unlike that of central Antarctica. Here, we present a new high‐resolution record of calcium from Dome C, Antarctica. Changes in flux of calcium, an indicator of dust input from other continents, should be synchronous across the region and probably the continent. Using Ca to synchronise records, we find that the main warming at the near‐coastal site of Taylor Dome was slower than suggested previously, and similar to that of central Antarctica. Until there is further evidence, it is still a reasonable hypothesis that Antarctic climate behaved more or less as a single unit during the transition.
Characterization of gas chromatography‐negative ion chemical ionization mass Spectrometry for ambient measurement of PAN: Potential interferences and long‐term sensitivity drift
Authors: Tanimoto Hiroshi , Hirokawa Jun , Kajii Yoshizumi , Akimoto Hajime
Published: February 2004

Gas chromatography/negative ion chemical ionization mass spectrometry (GC/NICI MS) is characterized, elucidating instrument performance for the continuous measurement of peroxyacetyl nitrate (PAN) and its homologues. Chromatograms and linear response at parts per trillion by volume (pptv) levels are examined to evaluate the accuracy of calibration using 4 types of base gases: dry nitrogen, dry synthetic air, purified compressed air, and thermally PAN‐decomposed air. The sensitivity to PAN is further checked against humidity, which may be a source of interference in ambient measurements. The experimental results indicate that oxygen, water vapor, and other trace gases in ambient air do not affect the PAN sensitivity. Although significant sensitivity drifts were observed during the course of measurements made at a remote site in Japan, this problem was overcome by performing frequent calibrations with isopropyl nitrate (IPN).
Mesoclimatic analysis of severe weather and ENSO interactions in North Carolina
Authors: Rhome Jamie R. , Niyogi Devdutta S. , Raman Sethu
Published: February 2004

Connections between regional severe weather occurrences and El Niño/Southern Oscillation (ENSO) are investigated. Monthly (1950 –1989) occurrences of tornado and wind/hail frequency are compared with sea surface temperature (SST) indices and anomalies in the tropical Pacific. Analyses indicate increase in wind/hail events/ days, during the months of April through June of La Niña years. No direct evidence is found between tornado frequency and ENSO classes. Using seasonal composite anomalies of upper‐air patterns, it is concluded that La Niña patterns leads to enhanced convection over North Carolina.
On the vertical velocity sodar measurement in the region of Dumont d'Urville, east Antarctica
Authors: Pettré Paul , Argentini Stefania
Published: February 2004

During a recent study of the katabatic boundary layer at Dumont d'Urville, a triaxial sodar ran continuously for two consecutive years, 1993 and 1994. This study aims to evaluate the capacity of sodar to measure the local vertical velocity, by comparison with the analyses and re‐analysis of the European Centre, and a basic evaluation using local soundings. It is found that the results of the operational analyses are distorted by an important bias. At the surface and coastal area the large scale vertical velocity is of the order of 1 cms−1, and can reach values as large as 5 cms−1. In the re‐analysis the difference between vertical velocity at the surface and 650 hPa is weak. At the surface inside the continent, in the area of Dome C, vertical velocity is weak, lower than 1 cms−1. The vertical velocity on a synoptic scale shows a seasonal cycle.
Comparison between SUPIM simulations and measured TEC for the January, 1997 storm
Authors: MacPherson B. , González S. A. , Pi X. , Kelley M. , Bailey G. J. , Sulzer M. P. , Hajj G. , Buonsanto M. , Wang C.
Published: February 2004

A method of extrapolating electron densities (Ne) from Incoherent Scatter Radar (ISR) data to high altitudes is presented, and is used to estimate the vertical Total Electron Content (TEC) over Arecibo. Although primarily intended for use on the Ne profiles obtained using the new topside frequency hopping mode at Arecibo which provides measurements to over 2000 km altitude, we show that if the O+ ‐H+ transition altitude is low enough to be observed, then the method may also be applied to the data taken using the standard World Day multi‐radar mode, and thus to a great fraction of the World Day data from low solar flux conditions. This method is applied to Arecibo ISR data taken during the January 6–11 1997 CEDAR storm period, and compared with measured TEC from the Global Positioning System (GPS) satellite network. In addition, the TEC is compared to TEC calculated from the Sheffield University Plasmasphere Ionosphere Model (SUPIM) as part of an ongoing project of model validation.
The auroral signature of earthward flow bursts observed in the magnetotail
Authors: Zesta Eftyhia , Lyons Lawrence R. , Donovan Eric
Published: February 2004

We present direct evidence that transient Earthward flow bursts in the magnetotail can produce an observable signature in the optical aurora. This signature is north‐south aligned auroral structures that are extensions of transient intensifications near the poleward boundary of the auroral oval. Our study focuses on the period from 0500 to 0700 UT on January 7, 1997, during which five distinct flow bursts are observed in the Geotail data. At that time, the spacecraft was located approximately 30 RE downtail on field lines that project down to the CANOPUS array of ground based instruments. We find that each of the flow bursts seen in the Geotail data is associated with an auroral poleward boundary intensification (PBI) observed in the CANOPUS meridian scanning photometer (MSP) data, which appears as a north‐south aligned auroral structure in the CANOPUS all‐sky imager (ASI) data. Based on these observations we estimate that the fast flows originated between 50 and 100 RE downtail.
Ulysses observations of the irregularly structured mid‐latitude solar wind during the approach to solar maximum
Authors: McComas D. J. , Gosling J. T. , Skoug R. M.
Published: February 2004

The Ulysses spacecraft reached 45°S heliolatitude in its second polar orbit on 5 February 2000. Solar wind observations over the first portion of Ulysses' second orbit have been remarkably different from those taken at mid‐latitudes throughout its first orbit. During these portions of its first orbit, Ulysses crossed back and forth between the fast and slow solar wind and encountered a persistent corotating interaction region (CIR) on each solar rotation. In contrast, as Ulysses climbed to mid‐latitudes in its second orbit, it observed highly irregular solar wind with much less periodic CIRs, and no entries thus far into the fast solar wind. In addition, the recent data include a higher frequency of coronal mass ejections (CMEs) than observed in Ulysses' previous orbit, as well as numerous interplanetary shocks associated with both the CMEs and CIRs. These observations demonstrate that the mid‐latitude solar wind structure becomes increasingly complex as solar activity increases and coronal streamers, small‐scale coronal holes, and CMEs arise at increasingly high latitudes.
A tidal explanation for the sunrise/sunset anomaly in HALOE low‐latitude nitric oxide observations
Authors: Marsh Daniel R. , Russell James M.
Published: February 2004

The difference in sunrise and sunset low‐latitude nitric oxide (NO) mixing ratios in the mesosphere and lower thermosphere (MLT) is shown to be consistent with a perturbation induced by the migrating diurnal tide. The vertical wind of the tide can induce factor of 2 changes over 12 hours at the equator. The vertical, latitudinal and temporal structure of NO perturbations closely matches the structure of vertical winds from a tidal model. In addition, previous observations of the seasonal and interannual variation in the tidal wind appear to correlate with NO variations.
Equatorial quasiperiodic echoes from field‐aligned irregularities observed over Jicamarca
Authors: Woodman Ronald F. , Chau Jorge L.
Published: February 2004

This is a report of so far undescribed equatorial quasiperiodic (EQP) echoes from field‐aligned irregularities from the E and lower F region. These echoes were observed on October 20, 1993 at the Jicamarca Radio Observatory in conjunction with a spectacular spread F event. We have identified two regions where striated EQP echoes are clearly observed. The time periods are between 1 and 5 min. In the first region (120–140 km) the slope of the striations is negative (apparent downward propagation), while in the second (160–200 km) the slope is positive. Moreover, in the first region the time periods (striation spacings) are smaller and the altitude rates of change are higher than those observed in the second region. Although these equatorial echoes appear somewhat similar to those seen at midlatitudes, we believe that the two phenomena are different. We have no explanation as yet for these EQP observations; our purpose in presenting these data is primarily to describe their properties in more detail than has been done in the past.
Localized convection flows and field‐aligned current generation in a kinetic model of the near‐Earth plasma sheet
Authors: Pritchett P. L. , Coroniti F. V.
Published: February 2004

Three‐dimensional (3‐D) particle simulations are used to determine the characteristic field‐aligned currents produced by an interchange‐driven, localized plasma jet impinging on the near‐Earth plasma sheet. The diversion of the plasma flow produces a region 2 sense current which enhances the cross‐tail current, while the primary flow provides a current to the ionosphere whose signature is consistent with the auroral streamers. The high beta interchange mode and localized flows resulting from a tailward gradient in the equatorial magnetic field provide a physical realization of the plasma bubble model of plasma sheet convection.
Coronal mass ejections, interplanetary ejecta and geomagnetic storms
Authors: Cane H. V. , Richardson I. G. , St. Cyr O. C.
Published: February 2004

Studies using SOHO spacecraft data have demonstrated that frontside halo coronal mass ejections (CMEs) detected by the LASCO coronagraphs generally precede geomagnetic storms. Nonetheless, about three quarters of such CMEs do not result in even moderate geomagnetic activity. We study the relationship of all the ejecta (interplanetary CMEs) which passed Earth during 1996–1999 to coronagraph CMEs and geomagnetic activity. We reach the following conclusions: (1) Only about half of frontside halo CMEs encounter the Earth; (2) The geoeffectiveness of ejecta depends strongly on the southward magnetic field strength and, for the same southward field, is irrespective of whether or not the ejecta has a magnetic cloud structure; (3) Transit speeds of ejecta to Earth are only loosely correlated with CME speeds, one influence being the prevailing solar wind conditions between the Sun and Earth; (4) Ejecta may be detected at Earth even when there is no preceding halo CME observed by LASCO. Such ejecta are not particularly geoeffective.
Eastward convection jet at the poleward boundary of the nightside auroral oval
Authors: A. M. Hamza , Huber M. , Lyatsky W. , Kustov A. V. , Andre D. , Sofko G.
Published: February 2004

The statistical study of the azimuthal convection flow in the midnight sector, as measured by the Saskatoon and the Stokkseyri SuperDARN radars, reveals the existence of an enhanced eastward convection stream around the poleward boundary of the auroral oval. The stream occupies two to three degrees and is located at geomagnetic latitudes 72–75°, which is indeed significantly poleward of the position of the center of the auroral oval. Poleward of the eastward convection stream, a westward convection stream is detected by the Saskatoon radar though not evident in the Stokkseyri radar measurements. The existence of the eastward convection stream at the poleward edge of the nightside auroral oval is very consistent with earlier results from the Akebono spacecraft. Such plasma flows are the source of possible plasma instabilities in the ionospheric E and F‐regions.
Thickness of tropical ice and photosynthesis on a snowball earth
Authors: McKay Christopher
Published: February 2004

On a completely ice‐covered “snowball” Earth the thickness of ice in the tropical regions would be limited by the sunlight penetrating into the ice cover and by the latent heat flux generated by freezing at the ice bottom—the freezing rate would balance the sublimation rate from the top of the ice cover. Heat transfer models of the perennially ice‐covered Antarctic dry valley lakes applied to the snowball Earth indicate that the tropical ice cover would have a thickness of 10 m or less with a corresponding transmissivity of > 0.1%. This light level is adequate for photosynthesis and could explain the survival of the eukaryotic algae.
Experimental vibrational Grüneisen ratio values for ϵ‐iron up to 330 GPa at 300 K
Authors: Anderson Orson L. , Dubrovinsky Leonid , Saxena Surendra K. , LeBihan T.
Published: February 2004

Experimental values for the vibrational Grüneisen ratio, γυ, for hexagonal close‐packed (hcp) iron, called epsilon (ϵ)‐iron, were obtained over a large compression range corresponding to Earth's inner‐core pressure. This was done by measuring the intensity change in x‐ray diffraction lines under pressure, P. X‐ray structural refinement using the Rietveld method on powder diffraction data yielded information on mean square displacement used to obtain the Debye temperature, Θ, as a function of compression, V/V0. The value of Θ was determined from the measured intensity of the diffraction lines, which arises from the mean squared amplitude < u² > measured in‐situ in the diamond cell. From the Debye relationship, γυ=−(∂ ln Θ/∂ ln V)T, we determined experimental data on γυ versus V of Fe (hcp) up to 330 GPa at 300 K. The measured value of γυ(V) is 1.18 at 330 GPa and 1.41 at 135 GPa.
Decreasing cloudiness over China: An updated analysis examining additional variables
Authors: Kaiser Dale P.
Published: February 2004

Trends in Chinese total cloud amount, surface air pressure, surface water vapor pressure, and surface relative humidity were analyzed for the period 1954–1994. The data were obtained from a database of 6‐hourly weather observations provided by the China Meteorological Administration. Seasonal and annual means of all four variables were computed for each of 196 stations and for China as a whole. Linear regression analysis was used to characterize seasonal and annual trends in these variables from 1954–1994, with the cloud amount record also extended through 1996 using a newly compiled global cloudiness database. Decreasing cloud amount trends are observed over much of China, as are increasing trends in surface air pressure. The spatial pattern of observed trends in water vapor pressure and relative humidity are more complex; a few scattered regions of China show increasing surface water vapor pressure, whereas surface relative humidity is found to increase in northwestern China and decrease in northeastern China (where the largest decreases in cloud amount are observed). The all‐China time series of total cloud amount (surface air pressure) shows a remarkable drop‐off (upswing) beginning in 1978.
A lower‐crustal event in the northeastern Mediterranean: The 1998 Adana earthquake (Mw= 6.2) and its aftershocks
Authors: Aktar Mustafa , Ergin Mehmet , Özalaybey Serdar , Tapirdamaz Cengiz , Yörük Ahmet , Biçmen Faruk
Published: February 2004

We analyse the main and aftershocks of the June 27, 1998 Adana earthquake using data from the short‐period Cilician seismograph network in order to investigate the seismotectonics of the northeastern Mediterranean region. The mainshock is found to have a pure left lateral strike‐slip mechanism (strike=50°, dip=85°, rake=10°, Mo=3.63×1018 Nm). The inferred strike direction of 50° N closely aligns with the surface trend of the Göksun Fault Zone (GFZ). The depth and size of the mainshock and the distribution of the aftershocks indicate that the rupture nucleated within the lower crust, and did not extend to shallower zones. This seismicity pattern indicates that these events are associated with actively interacting African and Anatolian lithospheres in a strike‐slip manner at depth. Thus, we propose that the southern segment of the GFZ belongs to the diffuse Africa‐Anatolia plate boundary and plays a major role in the plate kinematics of the northeastern Mediterranean.
The effect of an equilibrated melt phase on the shear creep and attenuation behavior of polycrystalline olivine
Authors: Gribb Tye T. , Cooper Reid F.
Published: February 2004

The impact of a chemically and texturally equilibrated melt phase on the shear creep and attenuation behaviors of polycrystalline olivine has been measured experimentally at seismic‐to‐subseismic frequencies. The experiments were performed on aggregates that had a particularly uniform and fine grain size (∼3 µm). The effect of the melt phase (∼5 vol%) is to decrease the (Newtonian) viscosity by a factor of ∼6; there is no dramatic disaggregation effect or melt‐induced plummeting of the shear modulus. Both the melt‐free and melt‐bearing aggregates display an attenuation “band” of the form QG−1 ∝ f−1 4. This response cannot be attributed to a variation in microstructure; it is intrinsic to the diffusional creep behavior. There is no unique effect of the melt phase on the attenuation response: the slight increase in absorption of partial melt specimens is explained fully by the effect of the texturally equilibrated melt on aggregate viscosity.
Magnetotelluric and geomagnetic depth soundings around the Torres Syncline Hinge, southeast Paraná Basin, Brazil
Authors: Padilha Antonio L. , Vitorello Ícaro
Published: February 2004

A MT/GDS survey has been carried out around the NW plunging Torres Syncline in the southeastern border of the Paraná Basin, in Brazil. Induction arrows show a NW‐trending conductive anomaly nearly coincident with the hinge of the syncline and ocean effects varying as a function of the distance from the coast. 2‐D inversions of MT data along two profiles parallel to the coast and across this anomaly have distinguished electrical anomalies in the upper crust. The most prominent of these anomalies is an electrical conduit dipping to the NW from a depth of 500 m at the coast to 1000 m at a distance of about 100 km further inland. The conductor, located in the crystalline basement, can be possibly ascribed to residual metasomatic fluids concentrated along the hinge of the downfolded Torres Syncline, as a fossil record of the Early Cretaceous volcanic events that affected the Paraná Basin and underlying lithosphere.
Ocean loading corrections for continuous GPS: A case study at the Canadian coastal site Holberg
Authors: Dragert H. , James T. S. , Lambert A.
Published: February 2004

The continuous GPS stations of the Western Canada Deformation Array (WCDA) are subject to movements due to the loading of the lithosphere by ocean tides. Using 4 weeks of continuous GPS data, this study examines the effects of ocean loading corrections at the coastal site HOLB. Theoretical ocean loading displacements were based on the Grenoble Global Model FES95.2, modified by detailed modeling of nearby coastal ocean cells. Positions for HOLB were obtained using the Bernese software for 3hr and 24hr solutions with hourly tropospheric delay estimates in both cases. Without ocean loading corrections, the 3hr‐computed heights had daily variations as large as 8 cm that were well correlated with tidal predictions. Application of ocean loading corrections to these solutions removed the tidal correlations and reduced the variance by a factor of two. The repeatability of the 24hr vertical positions was not significantly improved by the addition of ocean loading corrections. However, for these daily solutions without loading corrections, a significant amount of the relative vertical tidal motion of the station was absorbed in the (1hr) tropospheric delay estimates. We conclude that constraining station position for HOLB, in our case to a daily average, can bias short‐term estimates of zenith delay by up to 10 mm and, in turn, estimates of precipitable water vapour by several millimetres.
Future of the Arctic sea ice cover: Implications of an Antarctic analog
Authors: Martinson Douglas G. , Steele Michael
Published: February 2004

Recent observations reveal a significant change in the upper ocean characteristics of the eastern Arctic in 1995. The change is manifested through the loss of a near‐surface layer known as the cold halocline layer (CHL). Without the CHL, the Arctic water column looks and behaves like the Antarctic water column. The expected local impact is the appearance of significant winter ocean heat fluxes (15–20 W/m²) and reduction of winter ice growth by 70–80% relative to years in which the CHL was present. Preliminary results suggest a partial recovery of the CHL in the late 1990's, tracking the weakening of the Arctic Oscillation.