bluuebunny/crossref_metadata_2025 huggingface dataset:
Small Area Variation Analysis
Authors: Diehr Paula
Published: July 2005

Small area variation analysis examines the variation in the rates of performance of a medical procedure, such as an appendectomy, across geographic areas. The approach is used to identify procedures or DRGs in which there is too much variation, with the goal of improving guidelines or identifying outlying providers. Unless the number of procedures per area is very large, variations analyses present a variety of statistical challenges.
Informatics in the Health Sciences
Authors: Lehmann Harold P.
Published: July 2005

Informatics is the use of information technology, broadly conceived, to advance a domain of work or inquiry. Concerns within informatics divide into system, role, function, workflow, information repository, information tools, standards, and technology. Individual efforts go through four phases: model formulation, system development, system installation, and study of effects. Areas within health sciences informatics include medical informatics, nursing informatics, public health informatics, and statistics informatics.
Deformation Mechanisms of Nanostructured Al Alloys
Authors: Han B. Q. , Lavernia E. J.
Published: July 2005

Cryomilling has emerged in recent years as an effective approach to process large amounts of nanostructured Al alloys. In the present review, progress in our understanding of the microstructural characteristics and deformation behavior of nanostructured Al alloys processed via consolidation of cryomilled nanostructured powders is reviewed in an effort to elucidate salient findings and point out additional studies needed. A survey of published papers show that the microstructure of consolidated cryomilled Al alloys is comprised of equiaxed grains in the range of ∼ 50 nm to 200 nm, depending primarily on process parameters. Moreover, in many cases the microstructure consists of a supersaturated solid solution, despite the presence of significant amounts of alloying elements. As far as mechanical properties, the tensile behavior of these nanostructured Al systems is characterized by high strength and low strain hardening. The high strength was primarily attributed to three types of strengthening: grain size effect, solid solution hardening and Orowan strengthening. The low strain hardening or work softening behavior was accompanied with the occurrence of Lüders banding. Recent work suggests that there are two approaches that may be effectively used to address the lack of dislocation activity that typically accompany the presence of nanocrystalline grains < 10–50 nm. The first approach involves selective blending of powders to achieve a microstructure that contains multiple length scales (i.e., nanostructured, 50–200 nm, and submicron, 200–750 nm). The second approach involves thermal annealing in an effort to introduce small amounts of submicron grains for improvement of ductility. Recent related work is discussed herein.
Cover Picture: Polyaniline Nanofibers Prepared by Dilute Polymerization (Adv. Mater. 13/2005)
Authors: Chiou N.‐R. , Epstein A. J.
Published: July 2005

The cover image shows a scanning electron micrograph of polyaniline/camphorsulfonic acid nanofibers synthesized using dilute polymerization. The inset shows isolated branched nanofibers with diameters of 17–50 nm. On p. 1679, Chiou and Epstein report the preparation of these polyaniline nanofibers with controlled diameters via reducing the concentrations of both monomer and oxidant.
The In Situ Physiology of Pine Tree Like Organisms (PTLO) in Activated Sludge Foams
Authors: Eales Kathryn , Nielsen Jeppe L. , Kragelund Caroline , Seviour Robert , Nielsen Per H.
Published: July 2005

The in situ physiology of filamentous bacteria with acute angle branching, or Pine tree like organisms (PTLO), from activated sludge foams was investigated with a focus on its response to hydrophobic substrates. Microautoradiographic studies revealed that PTLO are very selective in their substrate utilization in foams, only taking up oleic acid among many substrates tested, but carrying this out under aerobic, anaerobic, and anoxic conditions. Data from applying a combination of in situ techniques indicated that a high proportion of the PTLO were metabolically inactive in the foam. Most showed only low respiratory activity as detected with the redox dye CTC and low intensity signals from FISH probing with 16S rRNA targeted probes. A strong correlation was noticed between their accumulation of storage material in the form of polyhydroxyalkanoates and their intensity of fluorescent FISH signals. In situ surface properties of these PTLO as visualized by the adhesion of fluorescent hydrophobic spheres to individual filaments suggest that their relative hydrophobicities reflected their in situ cell viability. Active ectoenzyme activity was detected in many filaments but this activity did not correspond to the substrate uptake data.
Biological Foam Control by Chemical Additives Dosing – Part II: Biological and Physico‐chemical Aspects
Authors: Ruz̆ic̆ková Iveta , Remes̆ova Z̆anetá , Vanz̆urová Karolína
Published: July 2005

Eight antifoaming agents (AAs) were tested in lab‐scale sequencing batch reactors. Basic physico‐chemical (foam formation, hydrophobicity, scum index, surface charge, extracellular polymers concentration and composition) and biological parameters (floc structure, filament abundance and identification, sludge volume index) were determined. No stable or long‐term effect of AAs dosing on the biological foam occurrence was observed.
The Structure of Liquid Methanol
Authors: Ludwig Ralf
Published: July 2005

A combination of density functional calculations of molecular clusters with a quantum cluster equilibrium (QCE) model provides evidence that liquid methanol is dominated by cyclic and/or lasso structures. Only cluster populations including these structures fit the measured thermodynamic and spectroscopic properties, such as heat of vaporization, heat capacity, NMR chemical shifts, and quadrupole coupling constants. On the other hand, cluster populations comprising open‐chain structures fail to reach the experimental values: the heat of vaporization is about 10 kJ mol−1 too low, and the proton chemical shift is insufficiently downfield‐shifted by about 1 ppm.
Isotopic Quantum Effects in Liquid Methanol
Authors: Ludwig Ralf
Published: July 2005

Density functional calculations (B3 LYP/6‐31+G*) on molecular clusters and a quantum cluster equilibrium (QCE) model were used to calculate thermodynamic and structural properties of four isotopically labeled methanol species. The method allowed the reproduction of the characteristic differences in boiling points and heats of vaporization. Structural changes were also detected and related to recent experimental findings. It was shown that isotopic effects clearly have a quantum‐mechanical origin.
Construction of the Six‐ and Five‐Membered Aza‐Heterocyclic Units of the Isoindoloisoquinolone Nucleus by Parham‐Type Cyclization Sequences –Total Synthesis of Nuevamine
Authors: Moreau Anne , Couture Axel , Deniau Eric , Grandclaudon Pierre
Published: July 2005

An efficient methodology for the synthesis of isoindolo[1,2‐a]isoquinolones based on two Parham‐type cyclizations allowing the formation of the five‐ and six‐membered nitrogenated rings from carbamate or diacylamine precursors is described. The synthetic potential of this method has been further illustrated by the total synthesis of the alkaloid nuevamine. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Gene therapy flexes muscle
Authors: VandenDriessche Thierry
Published: July 2005

This commentary highlights the promising results of recent studies in animal models of Duchenne muscular dystrophy and amyotrophic lateral sclerosis that have clearly demonstrated the potential of gene therapy for tackling these diseases. In the absence of effective drugs or other treatments, these advances in gene therapy technology represent the best hope for those patients and families that are blighted by these diseases.

Background

Diseases characterized by progressive muscle degeneration are often incurable and affect a relatively large number of individuals. The progressive deterioration of muscle function is like the sword of Damocles that constantly reminds patients suffering from these diseases of their tragic fate, since most of them will eventually die from cardiac or pulmonary dysfunction. Some of these disorders are due to mutations in genes that directly influence the integrity of muscle fibers, such as in Duchenne muscular dystrophy (DMD), a recessive X‐linked genetic disease. Others result from a progressive neurodegeneration of the motoneurons that are essential for maintaining muscle function, such as in amyotrophic lateral sclerosis (ALS), also commonly known as Lou Gehrig's disease. The genetic basis of DMD is relatively well understood as it is due to mutations in the dystrophin gene that encodes the cognate sarcolemmal protein. In contrast, the cause of ALS is poorly defined, with the exception of some dominantly inherited familial cases of ALS that are due to gain‐of‐function mutations in the gene encoding superoxide dismutase (SODG93A). Gene therapy for these disorders has been hampered by the inability to achieve widespread gene transfer. Moreover, since familial ALS is due to a dominant gain‐of‐function mutation, inhibition of gene expression (rather than gene augmentation) would be required to correct the phenotype, which is particularly challenging. Copyright © 2005 John Wiley & Sons, Ltd.
Towards a debugging system for sensor networks
Authors: Ramanathan Nithya , Kohler Eddie , Estrin Deborah
Published: July 2005

Due to their resource constraints and tight physical coupling, sensor networks afford limited visibility into an application's behavior. As a result it is often difficult to debug issues that arise during development and deployment. Existing techniques for fault management focus on fault tolerance or detection; before we can detect anomalous behavior in sensor networks, we need first to identify what simple metrics can be used to infer system health and correct behavior. We propose metrics and events that enable system health inferences, and present a preliminary design of Sympathy, a debugging tool for pre‐ and post‐deployment sensor networks. Sympathy will contain mechanisms for collecting system performance metrics with minimal memory overhead; mechanisms for recognizing application‐defined events based on these metrics; and a system for collecting events in their spatiotemporal context. The Sympathy system will help programmers draw correlations between seemingly unrelated, distributed events, and produce graphs that highlight those correlations. As an example, we describe how we used a preliminary version of Sympathy to help debug a complex application, Tiny Diffusion. Copyright © 2005 John Wiley & Sons, Ltd.
Management and configuration issues for sensor networks
Authors: Marrón Pedro José , Lachenmann Andreas , Minder Daniel , Gauger Matthias , Saukh Olga , Rothermel Kurt
Published: July 2005

In this paper, we define three of the key issues that need to be solved in order to provide efficient management and configuration of applications and system software in sensor networks: the distribution and management of roles within the network, efficient code distribution algorithms, and efficient on‐the‐fly code update algorithms for sensor networks. The first issue is motivated by the increasing heterogeneity of sensor network applications and their need for more complex (non‐homogeneous) network topologies and structures. The second one is motivated by the intrinsic energy constraint issues and, in general, the resource limitation of sensor networks. Finally, the third one is needed due to the nature of monitoring applications and optimization needs from applications that should be able to efficiently incorporate code updates so that the network can adapt to its surroundings on the fly. In this paper we present related work and some results for each of these issues as we have dealt with them within the TinyCubus project. Copyright © 2005 John Wiley & Sons, Ltd.
Sensor network software update management: a survey
Authors: Han Chih‐Chieh , Kumar Ram , Shea Roy , Srivastava Mani
Published: July 2005

Software management is a critical task in the system administration of enterprise‐scale networks. Enterprise‐scale networks that have traditionally comprised of large clusters of workstations are expanding to include low‐power ad hoc wireless sensor networks (WSN). The existing tools for software updates in workstations cannot be used with the severely resource‐constrained sensor nodes. In this article, we survey the software update techniques in WSNs. We base our discussion around a conceptual model for the software update tools in WSNs. Three components of this model that we study are the execution environment at the sensor nodes, the software distribution protocol in the network and optimization of transmitted updates. We present the design space of each component and discuss in‐depth the trade‐offs that need to be considered in making a particular design choice. The discussion is interspersed with references to deployed systems that highlight the design choices. Copyright © 2005 John Wiley & Sons, Ltd.
High molecular weight monodisperse polystyrene microspheres prepared by dispersion polymerization, using a novel bifunctional macromonomer
Authors: Jung Hyejun , Kim So Yeoun , Lee Kangseok , Lee Byung H. , Shim Sang Eun , Choe Soonja
Published: July 2005

A novel bifunctional vinyl‐terminated polyurethane macromonomer was applied to the dispersion polymerization of styrene in ethanol. Monodisperse polystyrene (PS) microspheres were successfully obtained above 15 wt % of macromonomer relative to styrene. The steep slope from the reduction of the average particle size reveals that the macromonomer can efficiently stabilize higher surface area of the particles when compared with a conventional stabilizer, poly(N‐vinylpyrrolidone). The stable and monodisperse PS microspheres having the weight‐average diameter of 1.2 μm and a good uniformity of 1.01 were obtained with 20 wt % polyurethane macromonomer. The grafting ratio of the PS calculated from 1H NMR spectra linearly increased up to 0.048 with 20 wt % of the macromonomer. In addition, the high molecular weights (501,300 g/mol) of PS with increased glass transition and enhanced thermal degradation temperature were obtained. Thus, these results suggest that the bifunctional vinyl‐terminated polyurethane macromonomer acts as a reactive stabilizer, which gives polyurethane‐grafted PS with a high molecular weight. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3566–3573, 2005
Quantum cascade lasers in magnetic field: An active region model
Authors: Savić I. , Milanović V. , Indjin D. , Ikonić Z. , Jovanović V. D. , Harrison P.
Published: July 2005

A model of the active region of a quantum well cascade laser (QCL) subjected to an externally applied magnetic field is presented, based on a solution of the coupled rate equations, assuming unity injection. Landau quantization induced by magnetic confinement imposes a need for a modification of the well‐established active region model in order to accurately describe the processes occurring in an entirely discrete spectrum. Landau level (LL) configuration has major consequences for scattering processes, enhancing or inhibiting them depending on the inter‐LL energy separation, and strongly modifies the population inversion and optical gain that can be estimated from the presented model. Numerical calculations were performed for a GaAs/AlGaAs QCL emitting at λ ≈ 11.4 μm in a magnetic field of 10–60 T. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical, electrical and structural characterization of CuInSe2 thin films
Authors: Calderón C. , Gordillo G. , Romero E. , Bolaños W. , Bartolo‐Pérez P.
Published: July 2005

The present issue of physica status solidi (b) comprises papers presented at the XVII Latin American Symposium on Solid State Physics (SLAFES 2004) in Havana, Cuba, 6–9 December 2004. Further papers from this conference are published in phys. stat. sol. (c) 2, No. 10 (2005).

The cover picture refers to the article [1] on polycrystalline CuInSe2 films by Clara Calderón et al. and shows the crystal structure of CuInSe2 (right) and that of the In‐rich phase CuIn3Se5 (left) which were used for the simulation and analysis of the X‐ray diffraction spectra.

Clara Lilia Calderón Triana is teacher at the Solar Cells Laboratory of Universidad Nacional de Colombia in Bogotá where she has been working on solar cells and semiconductor materials since 1995. In particular, she is fabricating thin film solar cells based on CuInSe2 and Cu(In,Ga)Se2. At SLAFES 2004, Clara Calderón received the physica status solidi Young Researcher Award for her second presentation entitled “Study of electrical transport properties of ZnO thin films used as front contact of solar cells” [2] which is published as Editor's Choice of this issue. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Plasma gradient effects on double-probe measurements in the magnetosphere
Authors: Laakso H. , Aggson T. L. , Pfaff R. F.
Published: July 2005

Abstract. The effects on double-probe electric field measurements induced by electron density and temperature gradients are investigated. We show that on some occasions such gradients may lead to marked spurious electric fields if the probes are assumed to lie at the same probe potential with respect to the plasma. The use of a proper bias current will decrease the magnitude of such an error. When the probes are near the plasma potential, the magnitude of these error signals, ∆E, can vary as ∆E ~ Te(∆ne/ne)+0.5∆Te, where Te is the electron temperature, ∆ne/ne the relative electron density variation between the two sensors, and ∆Te the electron temperature difference between the two sensors. This not only implies that the error signals will increase linearly with the density variations but also that such signatures grow with Te, i.e., such effects are 10 times larger in a 10-eV plasma than in a 1-eV plasma. This type of error is independent of the probe separation distance provided the gradient scale length is much larger than this distance. The largest errors occur when the probes are near to the plasma potential. At larger positive probe potentials with respect to the plasma potential, the error becomes smaller if the probes are biased, as is usually the case with spherical double-probe experiments in the tenuous magnetospheric plasmas. The crossing of a plasma boundary (like the plasmapause or magnetopause) yields an error signal of a single peak. During the crossing of a small structure (e.g., a double layer) the error signal appears as a bipolar signature. Our analysis shows that errors in double-probe measurements caused by plasma gradients are not significant at large scale (»1 km) plasma boundaries, and may only be important in cases where small-scale (<1 km), internal gradient structures exist. Bias currents tailored for each plasma parameter regime (i.e., variable bias current) would o1q1improve the double-probe response to gradient effects considerably.
The BEAN experiment - An EISCAT study of ion temperature anisotropies
Authors: McCrea I. W. , Jones G. O. L. , Lester M.
Published: July 2005

Abstract. Results are presented from a novel EISCAT special programme, SP-UK-BEAN, intended for the direct measurement of the ion temperature anisotropy during ion frictional heating events in the high-latitude F-region. The experiment employs a geometry which provides three simultaneous estimates of the ion temperature in a single F-region observing volume at a range of aspect angles from 0° to 36°. In contrast to most previous EISCAT experiments to study ion temperature anisotropies, field-aligned observations are made using the Sodankylä radar, while the Kiruna radar measures at an aspect angle of the order of 30°. Anisotropic effects can thus be studied within a small common volume whose size and altitude range is limited by the radar beamwidth, rather than in volumes which overlap but cover different altitudes. The derivation of line-of-sight ion temperature is made more complex by the presence of an unknown percentage of atomic and molecular ions at the observing altitude and the possibility of non-Maxwellian distortion of the ion thermal velocity distribution. The first problem has been partly accounted for by insisting that a constant value of electron temperature be maintained. This enables an estimate of the ion composition to be made, and facilitates the derivation of more realistic line-of-sight ion temperatures and temperature anisotropies. The latter problem has been addressed by assuming that the thermal velocity distribution remains bi-Maxwellian. The limitations of these approaches are discussed. The ion temperature anisotropies and temperature partition coefficients during two ion heating events give values intermediate between those expected for atomic and for molecular species. This result is consistent with an analysis which indicates that significant proportions of molecular ions (up to 50%) were present at the times of greatest heating.
The instability of internal gravity waves to localised disturbances
Authors: Vanneste J.
Published: July 2005

Abstract. The instability of an internal gravity wave due to nonlinear wave-wave interaction is studied theoretically and numerically. Three different aspects of this phenomenon are examined. 1. The influence of dissipation on both the resonant and the nonresonant interactions is analysed using a normal mode expansion of the basic equations. In particular, the modifications induced in the interaction domain are calculated and as a result some modes are shown to be destabilised by dissipation. 2. The evolution of an initial unstable disturbance of finite vertical extent is described as the growth of two secondary wave packets travelling at the same group velocity. A quasi-linear correction to the basic primary wave is calculated, corresponding to a localised amplitude decrease due to the disturbance growth. 3. Numerical experiments are carried out to study the effect of a basic shear on wave instability. It appears that the growing secondary waves can have a frequency larger than that of the primary wave, provided that the shear is sufficient. The instability of waves with large amplitude and long period, such as tides or planetary waves, could therefore be invoked as a possible mechanism for the generation of gravity waves with shorter period in the middle atmosphere.
On the formation of a plasma pressure anisotropy in the dayside magnetosheath
Authors: Rezhenov B. V. , Safargaleev V. V. , Lyatsky W. B.
Published: July 2005

Abstract. We present a numerical solution for the momentum equation of the magnetosheath particles that describes the distribution of the pressure anisotropy of the magnetosheath plasma in the midday meridian plane. The pressure anisotropy is a maximum near the magnetopause subsolar point (p⊥/p\\Vert ≌ 10). The pressure anisotropy is caused by two factors: particles with small pitch angles (V\\Vert>V⊥) which travel along the magnetic field lines away from the equatorial plane of the magnetosheath; and particles, after crossing the bowshock, which reach the bulk velocity component directed along the magnetic field lines again, away from the magnetosheath equatorial plane. This velocity increases with increasing distance from the subsolar point of the bowshock, and does not permit particles with large pitch angles (V⊥>V\\Vert) to move toward the equatorial plane.
Operational predictability of winter blocking at ECMWF: an update
Authors: Tibaldi S. , Ruti P. , Tosi E. , Maruca M.
Published: July 2005

Abstract. Seven winters of analyses and forecasts from the operational archives of the European Centre for Medium Range Weather Forecast had been previously analyzed to assess the performance of the model in forecasting blocking events. This work updates some of this previous diagnostic work to the last five winters, from 1987/88 to 1991/92. The data set therefore covers all winter seasons (DJF) from 1980/81 to 1991/92, and consists of daily northern hemisphere 500 hPa geopotential height analyses and of the ten corresponding forecasts verifying on the same day ("Lorenz data"). Local blocking and sector blocking have been defined, using different modifications of the original Lejenas and Økland index. The comparison between the first seven and the last five winters, within the restrictions imposed by limited length of the data set, suggests a much improved situation as far as model climatology of blocking is concerned, especially over the Euro-Atlantic region. Operational predictability of blocking as an initial value problem is also shown to be measurably improved, in both Atlantic and Pacific sectors. All such improvements are shown to have taken place together with a considerable reduction of the model systematic error. Nevertheless, forecasting blocking in the medium range remains a difficult task for the model. More work is needed to understand whether the improvements are to be ascribed to the increased model resolution or to better physical parametrisations.
On effective conductivity of the ionosphere with random irregularities
Authors: Alperovich L. , Chaikovsky I.
Published: July 2005

Abstract. The influence of stochastic irregularities of the ionosphere on its effective conductivity has been estimated. The study was carried out for large scale inhomogeneities and quasistationary electromagnetic fields. It is found, that Pedersen conductivity sharply increases in a strong geomagnetic field even for small stochastic ionospheric irregularities of the electron density. This peculiarity has to be taken into account during analysis of ionospheric and magnetospheric measurements.
The F-layer at sunrise
Authors: Rishbeth H. , Jenkins B. , Moffett R. J.
Published: July 2005

Abstract. It was noticed 60 years ago that at sunrise (i) the ionospheric critical frequency foF2 increases faster in winter than in summer and (ii) the increase begins at a greater solar zenith angle in winter. It was later suggested that this "seasonal sunrise anomaly" is due to a seasonal change of atomic/molecular ratio in the neutral air in the F2-layer. This paper uses the Sheffield University plasmasphere-ionosphere computational model (SUPIM) with the MSIS thermosphere model to examine the relative importance at sunrise of production, loss and diffusion processes, and the effect of neutral air winds. The results show that both (i) and (ii) can be explained in terms of neutral composition changes.
The influence of time-dependent wind on gravity-wave propagation in the middle atmosphere
Authors: Zhong L. , Sonmor L. J. , Manson A. H. , Meek C. E.
Published: July 2005

Abstract. Ray-tracing techniques are used to computationally investigate the propagation of gravity waves through the middle atmosphere, as characterized by the vertically varying CIRA-86 wind and temperature models, plus a tidal wind model that varies temporally as well as vertically. For the wave parameters studied here, the background wind variation has a much stronger influence on the ray path and changes in wave characteristics than does the temperature variation. The temporal variation of the tidal component of the wind changes the observed frequency, sometimes substantially, while leaving the intrinsic frequency unaltered. It also renders temporary any critical levels that occur in the tidal region. Different starting times for the rays relative to the tidal phase provide different propagation environments, so that the temporary critical levels appear at different heights. The lateral component of the tidal wind is shown to advect propagating wave packets; the maximum lateral displacement of a packet varies inversely with its vertical group velocity. Time-dependent effects are more pronounced in local winter than in summer.
Linear baroclinic instability in the presence of heat inflow from the lower boundary
Authors: Fantini M.
Published: July 2005

Abstract. A linear Eady model with a parameterization of heat influx from the lower boundary is studied analytically in order to obtain the characteristics of baroclinic normal modes modified by this non-adiabatic source. The results display a secondary maximum of growth rate at high wave numbers and a range of absolutely unstable waves, thus suggesting that the property observed among mid-latitude explosive cyclones of being near-stationary in the phase of maximum growth may be captured by this representation of the air-sea energy exchange.
Polar lacuna on ionograms. E- or F-region processes?
Authors: Stauning P.
Published: July 2005

Abstract. Lacuna on ionograms indicate conditions where the usual ionospheric reflections of vertically propagating radio waves transmitted from and subsequently received by an ionosonde are missing over a range of frequencies. Reflections from the lowermost E-region should still be observable contrary to the more usual cases where absorption processes in the underlying D-region removes the low-frequency part of the ionospheric reflections appearing in ionograms. It is emphasized below that lacuna cases related to E-region processes should be distinguished from lacunae related to processes in the F1 and F2 regions. This distinction appears to have been neglected in a recent paper.
Potential merits for substorm research from imaging of charge-exchange neutral atoms
Authors: Daglis I. A. , Livi S.
Published: July 2005

Abstract. The in situ observations of the Earth magnetosphere performed over the past decades of space research have provided a rather good understanding of many partial localized processes of the magnetospheric substorm. The continuing lack of global observations inhibits the construction of a coherent picture of the substorm as a whole, which is actually determined by the coupling of the partial processes. In this context the importance of global observations for the advancement of magnetospheric substorm studies is critical. This paper presents briefly a promising technique of global observations, namely the imaging of charge exchange neutral atoms, or neutral atom imaging (NAI) of the magnetosphere. Model and theoretical estimates of charge-exchange neutral atom fluxes, as well as appropriate spacecraft orbit and instrumentation requirements are presented and discussed for specific regions of interest and vantage points. The potential merits of NAI for substorm research are presented along with possible combinations with other types of observational methods. Substorm issues that would benefit from NAI should include among others the assessment of the ionospheric contribution to the hot magnetospheric plasma, the relative importance of various ionospheric ion source regions, the resolution of spatial and temporal characteristics of substorm ion injections. NAI observations can be precious complements to local observations and lead to the understanding of how local processes, many of which are resolved quite well today, combine to form the global process of the magnetospheric substorm.
Mesopause temperatures calculated from the O2(a1Δg) twilight airglow emission recorded at Maynooth (53.2°N, 6.4°W)
Authors: Mulligan F. J. , Galligan J. M.
Published: July 2005

Abstract. Spectra of the O2(a1Δg) airglow emission band at 1.27 µm have been recorded during twilight at Maynooth (53.2°N, 6.4°W) using a Fourier transform spectrometer. Synthetic spectra have been generated for comparison with the recorded data by assuming a particular temperature at the emitting altitude, and modelling the absorption of each line in the band as it propagates downward through the atmosphere. The temperature used in generating the synthetic spectra was varied until an optimum fit was obtained between the recorded and synthetic data; this temperature was then attributed to the altitude of the emitting layer. Temperatures derived using this technique for 91 twilight periods over an 18-month period exhibit a strong seasonal behaviour with a maximum in winter and minimum in summer. Results from this study are compared with temperatures calculated from the OH(3, 1) Meinel band recorded simultaneously. In winter OH temperatures exceed O2 values by about 10 K, whereas the opposite situation pertains in summer; this result is interpreted in terms of a possible change in the altitude of the mesopause as a function of season. Estimates of the twilight O2(0, 0) total band intensity indicate that its intensity is lower and that its decay is more rapid in summer than in winter, in agreement with earlier observations.
Variations in the strength of the Sq current system
Authors: Stening R. J.
Published: July 2005

Abstract. The strength of the Sq current system is measured by taking the difference between magnetic variations on either side of the current system focus. This is carried out for several longitude sectors. A distinct semiannual variation is sometimes found but its incidence varies with longitude, local time and hemisphere. Other semiannual effects in the ionosphere are reviewed and the possibility of a diurnal modulation of the strength of the 12-h tide is suggested.
Solar cycle and seasonal variations in F-region vertical drifts over Kodaikanal, India
Authors: Ramesh K. B. , Sastri J. H.
Published: July 2005

Abstract. Measurements of the changes in phase path of F-region reflections at normal incidence at Kodaikanal (77° 28'E, 10° 14'N, dip 3°N) from February 1991 to February 1993 are used to determine the variation of the equatorial evening F-region vertical drifts (V z) with season, solar and magnetic activity. It is found that on average, at Kodaikanal, the post-sunset peak in Vz(Vzp) is higher in equinox and local winter months than in local summer. The day-to-day variability in V zp is highest in summer and lowest in winter. This seasonal trend persists even on magnetically quiet days (Ap \\leq14). Vzp is found to increase with 10.7 cm solar flux in all three seasons but tends to saturate for large flux values (>230 units) during local summer and winter months. Magnetic activity [represented by Ap as well as the time-weighted accumulations of a p and ap (τ)] does not seem to have any statistically significant effect on Vzp , except during equinoctial months of moderate solar activity, when Vzp decreases as magnetic activity increases.
Lidar observations of middle atmosphere temperature variability
Authors: Gobbi G. P. , Souprayen C. , Congeduti F. , Di Donfrancesco G. , Adriani A. , Viterbini M. , Centurioni S.
Published: July 2005

Abstract. We discuss 223 middle atmosphere lidar temperature observations. The record was collected at Frascati (42°N–13°E), during the 41-month period January 1989-May 1992, corresponding to the maximum of solar cycle 22. The choice of this interval was aimed at minimizing the temperature variability induced by the 11-year solar cycle. The average climatology over the 41-month period and comparison with a reference atmosphere (CIRA86) are presented. Monthly temperature variability over the full period, during opposite quasi-biennial oscillation phases and on a short-term scale (0.5–4 h), is analyzed. Results indicate the 50–55-km region as less affected by variability caused by the natural phenomena considered in the analysis. Due to this minimum in natural noise characterizing the atmospheric temperature just above the stratopause, observations of that region are well suited to the detection of possible temperature trends induced by industrial activities.
Interannual variability of United States cloudiness
Authors: Kane R. P. , Gobbi D.
Published: July 2005

Abstract. United States cloudiness data for 1950–1992 show quasi-biennial (QBO) and quasi-triennial (QTO) oscillations which match partly with the QBO and QTO of the Southern Oscillation (SO) index (the Tahiti minus Darwin pressure), but not with the QBO of the 50-mb equatorial zonal wind. Cloudiness also shows significant periodicities near 4.2 and 7.5 years, and probably a sunspot cycle effect (periodicities 11–14 years), with minimum cloudiness at or soon after sunspot minima, though this could also be due to periodicities of 10 and 17 years observed in the SO index. During 1955–1970, cloudiness increased by about 1%. Thereafter, it remained almost steady for the eastern and central parts of the USA, but continued to rise until about 1980 for the western USA.
Climatological evaluation of some fluxes of the surface energy and soil water balances over France
Authors: Choisnel E. M. , Jourdain S. V. , Jacquart C. J.
Published: July 2005

Abstract. This paper presents some statistical evaluations of the surface energy and soil water balance fluxes, for a prairie-type canopy, using the Earth model with a double-reservoir system for the management of the soil water reserve and the regulation of actual evapotranspiration. The mean values of these fluxes are estimated from energy and water balance simulations done on a 30-year climatic reference period (1951–1980). From values of these fluxes calculated for each meteorological synoptic station, mappings of net radiation, actual evapotranspiration, drainage and conduction fluxes have been made over French territory. Lastly, a few conclusions pertaining to the spatial variability of fluxes and to the partition of rainfall between run-off and drainage on the one hand and replenishment of the soil water reserve on the other hand are drawn from these preliminary results.
Zonal drifts of ionospheric irregularities at temperate latitude in the Indian region
Authors: Kumar S. , Gwal A. K. , Pathan B. M. , Rao D. R. K.
Published: July 2005

Abstract. The systematic time differences observed in the onset of postsunset VHF scintillations recorded simultaneously at Ujjain (Geogr. lat. 23.2°N, Geogr. long. 75.6°E) and Bhopal (Geogr. lat. 23.2°N, Geogr. long. 77.6°E), situated at the peak of the anomaly crest in the Indian region, have been analysed to determine the zonal drifts of scintillation-producing irregularities. The method is based on the assumption that the horizontal movement of irregularities does not change while crossing the F-region cross-over points of these stations. The calculated velocities of irregularities indicate an eastward drift decreasing from about 180 m s–1 to 55 m s–1 during the course of night. In the premidnight period, the drifts are reduced under the magnetically disturbed conditions. The average east-west extension of irregularites is found to be in the range of 200–500 km.
The characteristics of mountain waves observed by radar near the west coast of Wales
Authors: Prichard I. T. , Thomas L. , Worthington R. M.
Published: July 2005

Abstract. Radar observations at 46.5 MHz of vertical-velocity perturbations at Aberystwyth (52.4°N, 4.1°W) have been used to examine the incidence of mountain waves and their dependence on local topography and the wind vector at low heights. A contrast is drawn between the effects of easterly winds passing over major topographical features to the east of the radar site and those of westerly winds crossing low coastal topographical features to the west. Estimates are made of the vertical flux of horizontal momentum associated with mountain waves, and the general influence of mountain-wave activity on vertical-velocity measurements at the site is assessed.
Solar wind velocity distribution on the heliospheric current sheet during Carrington rotations 1787-1795
Authors: Bala B. , Prabhakaran Nayar S. R.
Published: July 2005

Abstract. The solar wind velocity distribution in the heliosphere is best represented using a v-map, where velocity contours are plotted in heliographic latitude-longitude coordinates. It has already been established that low-speed regions of the solar wind on the source surface correspond to the maximum bright regions of the K-corona and the neutral line of the coronal magnetic field. In this analysis, v-maps on the source surface for Carrington rotations (CRs) 1787–1795, during 1987, have been prepared using the interplanetary scintillation measurements at Research Institute of Atmospherics (RIA), Nagoya Univ., Japan. These v-maps were then used to study the time evolution of the low-speed (\\leq450 km s–1) belt of the solar wind and to deduce the distribution of solar wind velocity on the heliospheric current sheet. The low-speed belt of the solar wind on the source surface was found to change from one CR to the next, implying a time evolution. Instead of a slow and systematic evolution, the pattern of distribution of solar wind changed dramatically at one particular solar rotation (CR 1792) and the distributions for the succeeding rotations were similar to this pattern. The low-speed region, in most cases, was found to be close to the solar equator and almost parallel to it. However, during some solar rotations, they were found to be organised in certain longitudes, leaving regions with longitudinal width greater than 30° free of low-speed solar wind, i.e. these regions were occupied by solar wind with velocities greater than 450 km s–1. It is also noted from this study that the low-speed belt, in general, followed the neutral line of the coronal magnetic field, except in certain cases. The solar wind velocity on the heliospheric current sheet (HCS) varied in the range 300–585 km s–1 during the period of study, and the pattern of velocity distribution varied from rotation to rotation.
Extended period of polar cap auroral display: auroral dynamics and relation to the IMF and the ionospheric convection
Authors: Vorobjev V. G. , Leontyev S. V. , Feldstein Ya. I.
Published: July 2005

Abstract. An unusually extended period (5 h) of polar cap auroral display on 3 August 1986 is examined. Auroras have been investigated using ground-based data as well as measurements from the IMP-8 spacecraft in interplanetary space and simultaneous observations from the polar-orbiting satellites Viking and DE-1 in the northern and southern hemispheres, respectively. It is found that visible Sun-aligned arcs are located inside the transpolar band of the θ-aurora observed from the satellite in ultraviolet wavelengths. The transpolar band can contain several Sun-aligned arcs that move inside the band toward the morning or evening side of the auroral oval independent of the direction of the band movement. Intensifications of polar cap auroras with durations of up to about 30 min are observed. No change has been found in either IMF parameters or substorm activity that can be related to these intensifications. The θ-aurora occurred during a 2-h period when the B z-component of the IMF was negative. A tendency is noted for dawnward (duskward) displacement of the transpolar band when By>0 (By<0) in the southern hemisphere. Simultaneous observations of auroral ovals during interplanetary Bz<0, By<0 and Bx>0 in both hemispheres and convection patterns for Bz<0 and By<0 have been displayed using satellite and ground-based measurements. It was found that the transpolar band of the -aurora in the sunlit hemisphere was situated in the region of large-scale downward Birkeland currents.
Equatorial night-time F-region zonal electric fields
Authors: Hari S. S. , Krishna Murthy B. V.
Published: July 2005

Abstract. Night-time F-region vertical electrodynamic drifts at the magnetic equatorial station, Trivandrum are obtained for a period of 2 years, 1989 and 1990 (corresponding to solar cycle maximum epoch), using ionosonde h'F data. The seasonal variation of the vertical drift is found to be associated with the longitudinal gradients of the thermospheric zonal wind. Further, the seasonal variation of the prereversal enhancement of the vertical drift is associated with the time difference between the sunset times of the conjugate E-regions (magnetic field line linked to F-region) which is indicative of the longitudinal gradients of the conductivity (of the E-region). The vertical drifts and the causative zonal electric fields at Trivandrum are compared with those at Jicamarca and F-region zonal electric field models. It is seen that the night-time downward drift (as also the causative westward electric field) at Jicamarca is greater than that at Trivandrum. The prereversal enhancement of the drift is greater at Jicamarca than at Trivandrum during the summer and the equinoxes, whereas during the winter the opposite is the case.
Role of the solar main magnetic dipole field in the solar-tropospheric relations. Part II. Dependence on the types of solar sources
Authors: Baranyi T. , Ludmány A.
Published: July 2005

Abstract. Two criteria have previously been reported for efficient solar-tropospheric relations through corpuscular channels: the appropriate Sun-Earth attitude (equinoxes) and the mutual orientations of the terrestrial and solar main magnetic dipole fields. The effect also depends on the geographical position. The present paper reports a further criterion. The solar-meteorological correlations also depend on the solar origin of the given corpuscular impact: disturbances originating from the polar and equatorial regions release opposite behaviours. We conclude that the solar-meteorological relations can only be described by taking into account the specific spatial situations and polarity distributions.
High spatial and temporal resolution observations of the ionospheric cusp
Authors: Pinnock M. , Rodger A. S. , Dudeney J. R. , Rich F. , Baker K. B.
Published: July 2005

Abstract. The Halley PACE HF radar has been operated in a new mode to provide very high time (10 s) and space (15 km) resolution measurements of the iono-spheric signatures of the cusp and the low-latitude boundary layer. The first data show that the iono-spheric signature of flux transfer events occur up to 300 km equatorward of regions showing the HF characteristics of the ionospheric cusp. Whilst larger flux transfer events are seen, on average, every 7 min, many much smaller and short-duration events have been identified. On one occasion DMSP data have been used to show that at least four flux transfer events are occurring simultaneously at the edge of the cusp over 2 h of MLT. There is strong, but not conclusive evidence, that reconnection at the magnetopause is both intermittent and patchy. These data also suggest that flux transfer events can be a significant contributor to the cross-polar cap potential.
A comparative study of the sunrise and sunset effects on the integrated field intensity of VLF atmospherics
Authors: Bhattacharya A. B. , Datta B. K. , Bhattacharya R.
Published: July 2005

Abstract. A comparative study is made of the stepped structure of atmospherics during sunrise and sunset hours at three harmonically related frequencies in the VLF band, observed at the coast of the Bay of Bengal. The occurrences of the steps, their duration, time sequence and amplitudes are critically examined. Our analysis reveals that the start times of the third and second steps of the sunrise effect are always before ground sunrise, while the start of the main step is distributed on both sides of it. During sunset hours, the onset time of the main step is before the local ground sunset, but for the second and third steps, the onset times are after that. The results are interpreted by considering the multi-hop propagation as well as the distributed noise sources surrounding the observing site.