bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of different blanching times on antioxidant properties in selected cruciferous vegetables
Authors: Amin Ismail , Lee Wee Yee
Published: June 2005

This study aimed to evaluate the effect of different blanching times on the antioxidant properties (antioxidant and free radical scavenging activities) and phenolic content of selected cruciferous vegetables. The study revealed that a 10‐min blanching time had a significant effect (p < 0.05) on the antioxidant properties and phenolic content of all the vegetables except for cabbage and mustard cabbage. The loss of antioxidant activity was highest in Chinese cabbage (40%) after 15 min of blanching, followed by cabbage (27%), Chinese white cabbage (19%), mustard cabbage (9%) and red cabbage (4%). Red cabbage had lost a total of 40% scavenging activity after 15 min of blanching followed by Chinese cabbage (38%), cabbage (36%), mustard cabbage (23%) and Chinese white cabbage (11%). Only Chinese cabbage showed an increase (p < 0.05) in total phenolic content after 15 min of blanching compared with other vegetables. Minimal heat treatment through blanching process is recommended to prevent the major loss of antioxidant properties and phenolic content in selected cruciferous vegetables. Copyright © 2005 Society of Chemical Industry
Camptocormia in a patient with multiple system atrophy
Authors: Skidmore Frank , Mikolenko Irene , Weiss Howard , Weiner William
Published: June 2005

The term “camptocormia” describes a severe forward‐flexed posture. Although initially used to describe a conversion disorder, early authors also recognized organic camptocormia occurring in old age, or “camptocormie senile,” as well as traumatic and arthritic camptocormia. More recently, camptocormia has been described in patients with Parkinson's disease and in an individual with parkinsonism. We describe a case of progressive camptocormia as part of the initial presentation of a patient with multiple system atrophy. © 2005 Movement Disorder Society
Dystonia and parkinsonism in GM1 type 3 gangliosidosis
Authors: Roze Emmanuel , Paschke Eduard , Lopez Nathalie , Eck Thomas , Yoshida Kunihiro , Maurel‐Ollivier Annie , Doummar Diane , Caillaud Catherine , Galanaud Damien , Billette De Villemeur Thierry , Vidailhet Marie , Roubergue Anne
Published: June 2005

GM1 gangliosidosis is due to β‐galactosidase deficiency. Only patients with type 3 disease survive into adulthood and develop movement disorders. Clinical descriptions of this form are rare, particularly in non‐Japanese patients. We describe four new patients and systematically analyze all previous reports found by a literature search and contacts with the authors for additional information. Generalized dystonia remained the predominant feature throughout the disease course and was often associated with akinetic–rigid parkinsonism. GM1 gangliosidosis must be considered as a cause of early‐onset generalized dystonia, particularly in patients with short stature and skeletal dysplasia. © 2005 Movement Disorder Society
Variability of motor unit discharge and force fluctuations across a range of muscle forces in older adults
Authors: Tracy Brian L. , Maluf Katrina S. , Stephenson Jennifer L. , Hunter Sandra K. , Enoka Roger M.
Published: June 2005

Variability of motor unit discharge is a likely contributor to the greater force fluctuations observed in old adults at low muscle forces. We sought to determine whether the variability of motor unit discharge rate underlies the fluctuations in force during steady contractions across a range of forces in young (n = 11) and old (n = 14) adults. The coefficient of variation (CV) for discharge rate and force were measured during a force‐matching task as the first dorsal interosseous muscle performed isometric contractions. The recruitment thresholds of the 78 motor units ranged from 0.04% to 34% of maximal voluntary contraction (MVC) force. The CV for discharge rate ranged from 7.6% to 46.2% and was greater (P < 0.05) for old adults (21.5% ± 7.7%) than young adults (17.3% ± 8.1%). Although the CV for force was similar for young and old subjects (2.53% ± 1.6%) across all target forces, it was greater for old adults at the lowest forces. Furthermore, there was a positive relation (r2 = 0.20, P < 0.001) between the CV for force and the CV for discharge rate across the range of recruitment thresholds. This relation was significant for old adults (r2 = 0.30, P < 0.001), but not for young adults (r2 = 0.06, P > 0.05). Thus, the normalized variability (CV) of motor unit discharge was greater in old adults and was related to the amplitude of force fluctuations across a broader range of forces than previously examined. These findings underscore the contribution of variability of motor unit activity to motor output in normal human aging. Muscle Nerve, 2005
Proteomics of the rat gut: Analysis of the myenteric plexus‐longitudinal muscle preparation
Authors: Marvin‐Guy Laure , Lopes Luísa V. , Affolter Michael , Courtet‐Compondu Marie‐Claude , Wagnière Sandrine , Bergonzelli Gabriela E. , Fay Laurent B. , Kussmann Martin
Published: June 2005

The enteric nervous system (ENS) – present all along the gastrointestinal tract – is the largest and most complicated division of the peripheral nervous system that can function independently of the brain. The peripheral nerve cells are organized in two separate but interconnected meshworks, called the myenteric and submucous plexus. The nervous control of intestinal motility is primarily governed by the myenteric plexus (MP), which lies in‐between the longitudinal‐ (LM) and circular‐muscle layers and regulates their functions. To determine whether the proteomic technology is adapted to the analysis of specific gut tissues, we dissected the MP‐LM layers from the jejunum, ileum, and colon of Long Evans rats, homogenized them, and separated the proteins using two‐dimensional gel electrophoresis. A subset of all the visualized protein spots, covering the entire range of molecular weights and isoelectric points, was then selected and further analyzed by matrix‐assisted laser desorption/ionization‐time of flight and liquid chromatography mass spectrometry. We identified around 80 proteins in each gut segment, and among those, five were segment‐specific. Most of the proteins identified were derived from muscle cells, but we also detected some neuron‐specific proteins. This study represents, to our knowledge, the first extensive protein catalog of a neuromuscular layer of the rat intestine and it may constitute the basis to understand pathophysiological mechanisms related to the ENS.
Two‐dimensional fluorescence difference gel electrophoresis analysis of the urine proteome in human diabetic nephropathy
Authors: Sharma Kumar , Lee SoHee , Han Steven , Lee Sungchun , Francos Barbara , McCue Peter , Wassell Richard , Shaw M. Alexander , RamachandraRao Satish P.
Published: June 2005

Urinary proteins may provide clues regarding pathogenesis of kidney disease as well as providing markers of disease activity. We employed two‐dimensional differential in‐gel electrophoretic analysis (2‐D DIGE) to assess multiple urine samples in patients with diabetic nephropathy. Patient samples were collected as timed overnight collections. All the patients had longstanding diabetes, impaired renal function, and overt proteinuria. Control and patient urinary protein were analyzed by 2‐D DIGE and DeCyder analysis. Ninety‐nine spots were significantly regulated in the urine proteome of the diabetic samples, with 63 up‐ and 36 down‐regulated. One spot corresponding to a pI 5–6 and a molecular weight between 45 and 66 kDa was consistently up‐regulated by 19‐fold across individuals in the diabetic group. Surface‐enhanced laser desorption/ionization‐time of flight analysis of in‐gel tryptic digest of this spot identified this protein as alpha 1 antitrypsin (AAT). ELISA of urine samples from a separate group of patients and controls confirmed a marked increase of AAT in diabetic patients. Immunostaining of human diabetic kidneys revealed up‐regulation of AAT in areas of renal fibrosis. In conclusion, we developed a method to analyze numerous urine samples from patients and allowed for detection and identification of regulated urine protein spots.
Differential protein expression in human gliomas and molecular insights
Authors: Chumbalkar Vaibhav C. , Subhashini Chanumolu , Dhople Vishnu M. , Sundaram Curam S. , Jagannadham Medicharla V. , Kumar Kafnam N. , Srinivas Pasumarti N. B. S. , Mythili Ravinutala , Rao Mulla K. , Kulkarni Mahesh J. , Hegde Sridevi , Hegde Alangar S. , Samual Cini , Santosh Vani , Singh Lalji , Sirdeshmukh Ravi
Published: June 2005

See original http://dx.doi.org/10.1002/pmic.200401202
The ‘Protection’ of Aborigines in colonial and early federation Australia: the role of population data systems
Authors: Kraly Ellen Percy , McQuilton John
Published: June 2005

This paper reveals the role of population data systems in the governmental management of Aborigines and Aboriginal communities in Australia during the colonial era, and the first several decades after federation in 1901. State control over Aboriginal affairs was paramount during this period. In varying degrees, each of the Australian states implemented policies and programmes concerning Aboriginal persons and communities in the areas of settlement and geographical mobility, employment, marriage and cohabitation, health, criminal activities, voting, and the education of children. Each of these areas of management suggests an important role of population statistics and data systems. This paper considers the colony, then state, of Victoria as the first in a series of case studies. Archival methods are used to examine records concerning Aboriginal policy and administration. In Victoria, the call for evidence and reports on the conditions of Aborigines is heard often throughout historical records of communication between colonial representatives and governors, and subsequently between state parliamentarians and Chief Protectors. The distribution of rations and blankets to Aborigines and the regulation of movement in and out of reserves similarly were monitored using demographic accounting and registration systems. The forced removal of Aborigines to reserves in some areas, and the prohibition of half‐caste persons from reserves in other locales, notably Victoria, were administered by the larger reserves through population registration and the recording and tabulation of information about individuals and families. The policy to treat Aborigines of ‘pure blood’ differently from persons of mixed heritage, and hence to maintain an official classification of lineage, similarly required population registration and classification of Aboriginal persons for legal, administrative and managerial purposes. This research contributes to the growing scholarly literature on the role of population data systems in the infliction of human rights violations. Copyright © 2005 John Wiley & Sons, Ltd.
Sex, life, death, geography: fragmentary remarks inspired by ‘Foucault's population geographies’
Authors: Philo Chris
Published: June 2005

This paper is prompted by Stephen Legg's contribution to the journal on the subject of ‘Foucault's population geographies’. It provides a brief appreciation of Legg's contribution, and uses his claims as a platform for reflecting further on what attention to the work of Michel Foucault – the French philosopher‐historian – can bring to the table of population geography. More specifically, it is argued that Foucault's concern for sex, its bio‐politics and bio‐history could be more explicitly foregrounded in the subdiscipline. Copyright © 2005 John Wiley & Sons, Ltd.
The rise of the small household: demographic change and household structure in Paris
Authors: Ogden Philip E. , Schnoebelen François
Published: June 2005

This paper examines the changing numbers and structure of households in the City of Paris during the 1980s and 1990s. It sets the findings in the context of the Paris agglomeration and considers the results in the light of broader demographic trends associated with the second demographic transition. Although part of a longer‐term historical process of declining household size, the growth of one‐person households was rapid in this period, accounting for most of the growth in numbers of households. Over 50% of all households were one‐person in 1999 in the City of Paris, and four‐fifths consisted of just one or two people. The greatest increase was in the pre‐retirement age groups. The paper examines the demographic structure of these households and their geographical distribution, raising questions about the relationship between household changes, occupational structure, housing markets and patterns of residential mobility. Whilst the analysis confirms the well‐established concentration of one‐person households in the central city, it indicates considerable dispersion of new household forms to the rest of the agglomeration. Moreover, although young adults continue to play an important role in the City of Paris, the effects of previous demographic change on the size of generations points to a sharp increase in older adults in their forties and fifties during the 1990s. As in other leading French cities, gender, occupational status and housing are found to be important ingredients in the explanation of one‐person households, with the increase in women in professional employment a particular feature. A case study of one quartier exemplifies these relationships. Copyright © 2005 John Wiley & Sons, Ltd.
Empirical evidence of regional population concentration in Europe, 1870–2000
Authors: Martí‐Henneberg Jordi
Published: June 2005

This paper presents empirical evidence to support the hypothesis that, over time, Europe's population has undergone progressive regional concentration. Using data at the regional level from the first (1870) until the most recent (2000) available censuses, it is shown that the most densely populated areas in 1870 have continued to absorb subsequent population increase, and that as a result, territorial inequalities with respect to population have been exacerbated. Our main contribution consists of measuring this phenomenon and studying the spatial distribution of population in Europe from a historical perspective. For example, a high correlation (0.83) was found between the population density patterns for 1870 and 2000. These results allow a better understanding of the organisation of European society and more specifically of the phenomenon of counter‐urbanisation, which has traditionally been observed at the local level but not at the regional one. To make this possible, we have built a new and comprehensive database on the distribution of population in Central and Western Europe between 1870 and 2000. In this paper we explain the methodology followed, which involves the combination of historical information from a variety of sources, to produce a homogeneous, regional‐scale database that considers changes in European administrative borders within recent history. This database has been produced to trace the evolution of regional population throughout this period and to provide an insight into the most important long‐term trends and spatial patterns affecting European population. Copyright © 2005 John Wiley & Sons, Ltd.
Partnering ‘out’ and fitting in: residential segregation and the neighbourhood contexts of mixed‐race households
Authors: Holloway Steven R. , Ellis Mark , Wright Richard , Hudson Margaret
Published: June 2005

This analysis considers how racial segregation affects the residential geographies of households headed by mixed‐race couples. We also become interested in assessing whether diverse households live in diverse places. To measure neighbourhood diversity, we develop a new index of diversity based on the exposure index. The analysis of 12 large US metropolitan areas finds that race (in tandem with status markers like income) and nativity provide some of the best understandings of the neighbourhood geographies of mixed‐race households. The study also reveals that instead of fitting into and thus reinforcing the existing racialised urban spatial structure, some households formed by ‘partnering out’ live in spaces characterised by their racial diversity. We focus on the mixed‐race household because such a collective constitutes a scale at which mixed‐race contact takes place and a site for identity construction of individuals, partners, and the surrounding neighbourhood. Copyright © 2005 John Wiley & Sons, Ltd.
Postcards from the edge: maintaining the ‘alternative’ character of fair trade
Authors: Low William , Davenport Eileen
Published: June 2005

This paper argues that the pressures for fair trade to substantially increase market access for marginalized producers in the global South and subsequently move fair trade out of niche into mainstream markets is reshaping the boundaries of the movement. We suggest that going mainstream carries with it the danger of appropriation of the more convenient elements of fair trade by the commercial sector and loss of the more radical edges. This paper examines the changing discourse surrounding fair trade, critically reflecting on the movement's history to understand how its evolution to date might influence its possible futures. The paper concludes by exploring how various elements within the fair trade movement are trying to retain a radical edge in order to continue to provide a critique of the dominant paradigm of business and trade. Copyright © 2005 John Wiley & Sons, Ltd and ERP Environment.
What Tanzania's coffee farmers can teach the world: a performance‐based look at the fair trade–free trade debate
Authors: Parrish Bradley D. , Luzadis Valerie A. , Bentley William R.
Published: June 2005

Questions remain about the effectiveness of fair trade, especially in comparison with free trade approaches to development. Both strategies seek to benefit smallholder farmers in lower‐income countries, who are vulnerable to declining and fluctuating commodity prices and rising production costs. This study examines two prominent market‐based interventions, Fairtrade certification and TechnoServe business development, as they are implemented at two coffee producer organizations in Tanzania. Qualitative and secondary quantitative data were collected using rapid appraisal methodology during three months of field research. The data were analyzed using the sustainable livelihood framework. This study concludes that both intervention strategies yield potentially valuable results for smallholders in multiple domains, but each is distinctly suited to specific market conditions. Implications of the study's findings are discussed in terms of an emerging consensus on intervention strategies. Copyright © 2005 John Wiley & Sons, Ltd and ERP Environment.
Keeping trade fair: governance challenges in the fair trade coffee initiative
Authors: Taylor Peter Leigh , Murray Douglas L. , Raynolds Laura T.
Published: June 2005

Fair trade has gained attention as an innovative market‐based mechanism for addressing social and environmental problems exacerbated by conventional global markets. Yet such initiatives are also regulatory mechanisms that establish voluntary alternative arrangements for governing production, commercialization and consumption of global commodities. Based on a recent study of fair trade coffee experiences in Latin America, this paper explores the changes that fair trade represents in governance of the coffee commodity chain. It argues that fair trade coffee governance is shaped both by formal organizational arrangements for coordination and control and, less formally, by the social and political relations embedded in fair trade's commodity chain. Fair trade's alternative governance arrangements represent one of the initiative's major accomplishments but also pose some of its most significant challenges for the future. Copyright © 2005 John Wiley & Sons, Ltd and ERP Environment.
Osteogenesis imperfecta: Evidence for the existence of an abnormal amino acid sequence in the molecule of dermal collagen
Authors: Heathcote J. G. , Al‐Alawi Samirah
Published: June 2005

A collagen‐type pattern of peptide and amino acid spots was obtained when partial hydrolysates of normal human dermis were examined by a specially developed thin‐layer chromatographic (TLC) ‘finger‐printing’ technique. The pattern was consistent and independent of age and sex. Two clinically similar cases of osteogenesis imperfecta congenita gave identical patterns which differed in specific regions from those given by their age‐matched, normal controls. A single case of osteogenesis imperfecta tarda showed the same overall pattern as the congenita cases. It is concluded that an abnormal amino acid sequence occurs in the collagen molecule of both types of osteogenesis imperfecta.
The characteristics of acid 1,4‐α‐glucosidase in various human adult and fetal tissues
Authors: Shin‐Bühring Y. S. , Unterreithmeier J. , Wilsmann T. , Schaub J.
Published: June 2005

Deficiency of acid 1,4‐α‐glucosidase (EC 3.2.1.20) is associated with Pompe's disease (McKusick 23230), generalized glycogen storage disease type II. The deficiency of this enzyme has been demonstrated in various human tissues and cultivated cells from patients with Pompe's disease. Prenatal and postnatal diagnosis of this genetic disorder can be established by a simple procedure measuring the enzyme activity even with artificial substrates. However, there remain some questions concerning enzyme characteristics of α‐glucosidase in various human tissues and the changes occurring during development.
A refinement-based process algebra for timed automata
Authors: Cattani Stefano , Kwiatkowska Marta
Published: June 2005

We propose a real-time extension to the process algebra CSP. Inspired by timed automata, a very successful formalism for the specification and verification of real-time systems, we handle real time by means of clocks, i.e. real-valued variables that increase at the same rate as time. This differs from the conventional approach based on timed transitions. We give a discrete trace and failures semantics to our language and define the resulting refinement relations. One advantage of our proposal is that it is possible to automatically verify refinement relations between processes. We demonstrate how this can be achieved and under which conditions.
On the current-voltage relationship in fluid theory
Authors: Janhunen P.
Published: June 2005

Abstract. The kinetic theory of precipitating electrons with Maxwellian source plasma yields the well-known current-voltage relationship (CV-relationship; Knight formula), which can in most cases be accurately approximated by a reduced linear formula. Our question is whether it is possible to obtain this CV-relationship from fluid theory, and if so, to what extent it is physically equivalent with the more accurate kinetic counterpart. An answer to this question is necessary before trying to understand how one could combine time-dependent and transient phenomena such as Alfvénic waves with a slowly evolving background described by the CV-relationship. We first compute the fluid quantity profiles (density, pressure etc.) along a flux tube based on kinetic theory solution. A parallel potential drop accumulates plasma (and pressure) below it, which explains why the current is linearly proportional to the potential drop in the kinetic theory even though the velocity of the accelerated particles is only proportional to the square root of the accelerating voltage. Electron fluid theory reveals that the kinetic theory results can be reproduced, except for different numerical constants, if and only if the polytropic index γ is equal to three, corresponding to one-dimensional motion. The convective derivative term v·∇v provides the equivalent of the "mirror force" and is therefore important to include in a fluid theory trying to describe a CV-relationship. In one-fluid equations the parallel electric field, at least in its functional form, emerges self-consistently. We find that the electron density enhancement below the potential drop disappears because the magnetospheric ions would be unable to neutralize it, and a square root CV-relationship results, in disagreement with kinetic theory and observations. Also, the potential drop concentrates just above the ionosphere, which is at odds with observations as well. To resolve this puzzle, we show that considering outflowing ionospheric ions restores the possibility of having the acceleration region well above the ionosphere, and thus the electron kinetic (and fluid, if γ=3) theory results are reproduced in a self-consistent manner. Thus the inclusion of ionospheric ions is crucial for a feasible CV-relationship in fluid theory. Constructing a quantitative fluid model (possibly one-fluid) which reproduces this property would be an interesting task for a future study.Key words. Ionosphere (ionosphere-magnetosphere interactions; particle precipitation) · Magnetospheric physics (magnetosphere-ionosphere interactions)
Hydromagnetic spectroscopy of the magnetosphere with Pc3 geomagnetic pulsations along the 210° meridian
Authors: Pilipenko V. , Yumoto K. , Fedorov E. , Yagova N.
Published: June 2005

Abstract. Analysis of Pc3 observational data along the 210° magnetic meridian showed a complicated frequency-latitude structure at middle latitudes. The observed period-latitude distributions vary between events with a "noisy source": the D component has a colored-noise spectrum, while the spectrum of H component exhibits regular peaks that vary with latitude, and events with a "band-limited source": the spectral power density of the D component is enhanced at certain frequencies throughout the network. For most ULF events a local gap of the H component amplitude has been exhibited at both conjugate stations at L ~ 2.1. A quantitative interpretation has been given assuming that band-limited MHD emission from an extra-magnetospheric source is distorted by local field line resonances. Resonant frequencies had been singled out with the use of the asymmetry between spectra of H and D components. Additionally, a local resonant frequency at L ~ 1.6 was determined by the quasi-gradient method using the data from nearly conjugate stations. The experimentally determined local resonance frequencies agree satisfactorily with those obtained from a numerical model of the Alfven resonator with the equatorial plasma density taken by extrapolation of Carpenter-Anderson model. We demonstrate how simple methods of hydromagnetic spectroscopy enable us to monitor simultaneously both the magnitude of the IMF and the magnetospheric plasma density from ULF data.Key words. Magnetospheric physics (Magnetosphere-ionosphere interactions; MHD waves and instabilities; plasmasphere)
A numerical method to compute Euler potentials for non dipolar magnetic fields
Authors: Peymirat C. , Fontaine D.
Published: June 2005

Abstract. The magnetospheric magnetic field may be conveniently described by two scalar functions (α, β), known as the Euler potentials. They are not uniquely defined, and they may be difficult to derive for configuration more complex than a simple dipole. We propose here a simple numerical method to compute one possible pair (α, β). In magnetospheric regions of closed field lines, α can be chosen as a function of the tube volume of unit magnetic flux. The method can be applied to a wide class of magnetic fields which describe the magnetospheric domain of closed field lines and the conjugated ionosphere. Here, it is used with the T87 Tsyganenko model. The results coincide with the dipolar potentials at close distances from the Earth. At larger distances, they display an increasing distortion with the radial distance (or the invariant latitude in the ionosphere) and the magnetic activity. In the magnetosphere, the contours of α and β are stretched towards the nightside. In the ionosphere, they also extend towards the nightside and present major distortions in a narrow ring at the polar cap boundary, which maps distant boundary layers in the magnetosphere.Key words. Ionosphere (ionosphere-magnetosphere interactions; modeling and forecasting). Magnetospheric physics (plasma convection).
Spectral characteristics of waves and particles in the model of cyclotron wave-particle interactions near plasmapause
Authors: Pasmanik D. l. , Trakhtengerts V. Y.
Published: June 2005

Abstract. Further analysis of energetic electron precipitation at the evening sector of magnetosphere is performed. In the framework of the quantitative model of cyclotron wave-particle interactions developed in the previous Pasmanik et al. paper, the case of finite spread over energies of initial energetic electron distribution is studied. The solution for distribution function of energetic electron is found. The energetic spectrum of trapped and precipitating electrons and whistler wave spectrum are analysed.Key words. Magnetospheric physics (energetic particles · precipitating; energetic particles · trapped); · Space plasma physics (wave-particle interactions).
Diurnal and semidiurnal tide in the upper middle atmosphere during the first year of simultaneous MF radar observations in northern and southern Japan (45°N and 31°N)
Authors: Hocke K. , Igarashi K.
Published: June 2005

Abstract. The climatology of mean wind, diurnal and semidiurnal tide during the first year (1996-1997) of simultaneous wind observations at Wakkanai (45.4°N, 141.7°E) and Yamagawa (31.2°N, 130.6°E) is presented. The locations of the radars allow us to describe the latitudinal dependence of the tides. Tidal amplitude and phase profiles are compared with those of the global scale wave model (GSWM). While the observed amplitude profiles of the diurnal tide agree well with the GSWM values, the observed phase profiles often indicate longer vertical wavelengths than the GSWM phase profiles. In contrast to the GSWM simulation, the observations show a strong bimodal structure of the diurnal tide, with the phase advancing about 6 hours from summer to winter.Key words. Meteorology and atmospheric dynamics (middle atmosphere dynamics; waves and tides)
Validation of GOME total ozone by means of the Norwegian ozone monitoring network
Authors: Hansen G. , Dahlback A. , Tønnessen F. , Svenøe T.
Published: June 2005

Abstract. The Global Ozone Monitoring Experiment (GOME) onboard the ERS-2 satellite has been in operation since July 1995. The Norwegian ground-based total ozone network has played an important role both in the main validation during the commissioning phase and in the validation of upgraded versions of the analysis algorithms of the instrument. The ground-based network consists of various spectrometer types (Dobson, Brewer, UV filter instruments). The validation of the second algorithm version used until January 1998 reveals a very good agreement between GOME and ground-based data at solar zenith angles <60° and deviations of GOME total ozone data from ground-based data of up to ±60 DU (~20%) at zenith angles >60°. The deviations strongly depend on the season of the year, being negative in summer and positive in winter/spring, The deviations furthermore show a considerable scattering (up to ±25 DU in monthly average values of 5° SZA intervals), even in close spatial and temporal coincidence with ground-based measurements, especially in the high Arctic. The deviations are also dependent on the viewing geometry/ground pixel size with an additional negative offset for the large pixels used in the backswath mode and at solar zenith angles >85°, compared to forward-swath pixels.Key words. Atmospheric composition and structure (middle atmosphere · composition and chemistry; instruments and techniques)
Conjugate observations of the day-side reconnection electric field: A GEM boundary layer campaign
Authors: Pinnock M. , Rodger A. S. , Baker K. B. , Lu G. , Hairston M.
Published: June 2005

Abstract. Data from HF-radars are used to make the first simultaneous conjugate measurements of the day-side reconnection electric field. A period of 4 h around local magnetic noon are studied during a geospace environment modeling (GEM) boundary layer campaign. The interplanetary magnetic field (IMF) was southward whilst the eastward component (By) was variable. The flow patterns derived from the radar data show the expected conjugate asymmetries associated with  IMF |By| > 0. High-time resolution data (50 and 100 s) enable the flow of plasma across the open/closed field line boundary (the separatrix) to be studied in greater detail than in previous work. The latitude of the separatrix follows the same general trend in both hemispheres but shows a hemispherical difference of 4°, with the summer cusp at higher latitude, as expected from dipole tilt considerations. However, the short-time scale motion of the separatrix cannot be satisfactorily resolved within the best resolution (300 m s-1) of the experiment. The orientation of the separatrix with respect to magnetic latitude is found to follow the same trend in both hemispheres and qualitatively fits that predicted by a model auroral oval. It shows no correlation with IMF By. However, the degree of tilt in the Northern (summer) Hemisphere is found to be significantly greater than that given by the model oval. The convection pattern data show that the meridian at which throat flow occurs is different in the two hemispheres and is controlled by IMF By, in agreement with empirically derived convection patterns and theoretical models. The day-side reconnection electric field values are largest when the radar's meridian is in the throat flow or early afternoon flow regions. In the morning or afternoon convection cells, the reconnection electric field tends to zero away from the throat flow region. The reconnection electric field observed in the throat flow region is bursty in nature.Key words. Ionosphere (plasma convection; polar ionosphere) · Magnetospheric physics (magnetosphere-ionosphere interactions)
Localized structure in the cusp and high-latitude ionosphere: a modelling study
Authors: Balmforth H. F. , Moffett R. J. , Rodger A. S.
Published: June 2005

Abstract. The ionospheric signature of a flux transfer event (FTE) seen in EISCAT radar data has been used as the basis for a modelling study using a new numerical model of the high-latitude ionosphere developed at the University of Sheffield, UK. The evolution of structure in the high-latitude ionosphere is investigated and examined with respect to the current views of polar patch formation and development. A localized velocity enhancement, of the type associated with FTEs, is added to the plasma as it passes through the cusp. This is found to produce a region of greatly enhanced ion temperature. The new model can provide greater detail during this event as it includes anisotropic temperature calculations for the O+ ions. This illustrates the uneven partitioning of the energy during an event of this type. O+ ion temperatures are found to become increasingly anisotropic, with the perpendicular temperature being substantially larger than the parallel component during the velocity enhancement. The enhanced temperatures lead to an increase in the recombination rate, which results in an alteration of the ion concentrations. A region of decreased O+ and increased molecular ion concentration develops in the cusp. The electron temperature is less enhanced than the ions. As the new model has an upper boundary of 10 000 km the topside can also be studied in great detail. Large upward fluxes are seen to transport plasma to higher altitudes, contributing to the alteration of the ion densities. Plasma is stored in the topside ionosphere and released several hours after the FTE has finished as the flux tube convects across the polar cap. This mechanism illustrates how concentration patches can be created on the dayside and be maintained into the nightside polar cap.Key words. Ionosphere (ionosphere-magnetosphere interactions; polar ionosphere). Magnetospheric physics (magnetopause · cusp and boundary layers)
Strong atmospheric disturbances as a possible origin of inner zone particle diffusion
Authors: Pokhotelov O. A. , Pilipenko V. A. , Parrot M.
Published: June 2005

Abstract. A new mechanism of the atmosphere-magnetosphere interaction, which might be called "acoustic-magnetospheric cyclotron accelerator", is proposed. The idea of this mechanism stems from the fact that strong acoustical perturbations in the ionosphere (e.g., due to earthquakes, thunderstorms, etc.) may generate magnetic disturbances in the magnetosphere. Then, the latter will induce local resonant acceleration and subsequent inward diffusion of trapped particles. This idea may be fruitful in the interpretation of some occasional increases in inner zone particle fluxes which do not correlate with the solar or magnetospheric activities.Key words. Ionosphere (active experiments; ionosphere-atmosphere interactions; particle acceleration)
New aspects of plasma sheet dynamics - MHD and kinetic theory
Authors: Wiechen H.
Published: June 2005

Abstract. Magnetic reconnection is a process of fundamental importance for the dynamics of the Earth's plasma sheet. In this context, the development of thin current sheets in the near-Earth plasma sheet is a topic of special interest because they could be a possible cause of microscopic fluctuations acting as collective non-idealness from a macroscopic point of view. Simulations of the near-Earth plasma sheet including boundary perturbations due to localized inflow through the northern (or southern) plasma sheet boundary show developing thin current sheets in the near-Earth plasma sheet about 810 RE tailwards of the Earth. This location is largely independent from the localization of the perturbation. The second part of the paper deals with the problem of the macroscopic non-ideal consequences of microscopic fluctuations. A new model is presented that allows the quantitative calculation of macroscopic non-idealness without considering details of microscopic instabilities or turbulence. This model is only based on the assumption of a strongly fluctuating, mixing dynamics on microscopic scales in phase space. The result of this approach is an expression for anomalous non-idealness formally similar to the Krook resistivity but now describing the macroscopic consequences of collective microscopic fluctuations, not of collisions.Key words. Magnetospheric physics (plasma sheet) · Space plasma physics (kinetic and MHD theory; magnetic reconnection)
Sausage mode instability of thin current sheets as a cause of magnetospheric substorms
Authors: Büchner J. , Kuska J.-P.
Published: June 2005

Abstract. Observations have shown that, prior to substorm explosions, thin current sheets are formed in the plasma sheet of the Earth's magnetotail. This provokes the question, to what extent current-sheet thinning and substorm onsets are physically, maybe even causally, related. To answer this question, one has to understand the plasma stability of thin current sheets. Kinetic effects must be taken into account since particle scales are reached in the course of tail current-sheet thinning. We present the results of theoretical investigations of the stability of thin current sheets and about the most unstable mode of their decay. Our conclusions are based upon a non-local linear dispersion analysis of a cross-magnetic field instability of Harris-type current sheets. We found that a sausage-mode bulk current instability starts after a sheet has thinned down to the ion inertial length. We also present the results of three-dimensional electromagnetic PIC-code simulations carried out for mass ratios up to Mi / me=64. They verify the linearly predicted properties of the sausage mode decay of thin current sheets in the parameter range of interest.Key words. Magnetospheric physics (plasma waves and instabilities; storms and substorms) · Space plasma physics (magnetic reconnection)
Resonant enhancement of relativistic electron fluxes during geomagnetically active periods
Authors: Roth I. , Temerin M. , Hudson M. K.
Published: June 2005

Abstract. The strong increase in the flux of relativistic electrons during the recovery phase of magnetic storms and during other active periods is investigated with the help of Hamiltonian formalism and simulations of test electrons which interact with whistler waves. The intensity of the whistler waves is enhanced significantly due to injection of 10-100 keV electrons during the substorm. Electrons which drift in the gradient and curvature of the magnetic field generate the rising tones of VLF whistler chorus. The seed population of relativistic electrons which bounce along the inhomogeneous magnetic field, interacts resonantly with the whistler waves. Whistler wave propagating obliquely to the magnetic field can interact with energetic electrons through Landau, cyclotron, and higher harmonic resonant interactions when the Doppler-shifted wave frequency equals any (positive or negative) integer multiple of the local relativistic gyrofrequency. Because the gyroradius of a relativistic electron may be the order of or greater than the perpendicular wavelength, numerous cyclotron, harmonics can contribute to the resonant interaction which breaks down the adiabatic invariant. A similar process diffuses the pitch angle leading to electron precipitation. The irreversible changes in the adiabatic invariant depend on the relative phase between the wave and the electron, and successive resonant interactions result in electrons undergoing a random walk in energy and pitch angle. This resonant process may contribute to the 10-100 fold increase of the relativistic electron flux in the outer radiation belt, and constitute an interesting relation between substorm-generated waves and enhancements in fluxes of relativistic electrons during geomagnetic storms and other active periods.Key words. Magnetospheric physics (energetic particles · trapped; plasma waves and instabilities; storms and substorms)
Solar and seasonal dependence of ion frictional heating
Authors: Davies J. A. , Lester M. , McCrea I. W.
Published: June 2005

Abstract. Ion frictional heating constitutes one of the principal mechanisms whereby energy, originating in the solar wind, is deposited into the Earth's ionosphere and ultimately the neutral atmosphere. Common programme observations by the EISCAT UHF radar system, spanning the years 1984 to 1995, provide the basis for a comprehensive statistical study of ion frictional heating, results of which are documented in this and a previous paper by the authors. In the present work, the authors demonstrate the solar and seasonal dependence of the universal time distribution of frictional heating, and explain these results with reference to corresponding dependences of the ion velocity. Although EISCAT observes a significant increase in the occurrence of enhanced ion velocities associated with increased solar activity, the latter characterised according to the prevailing 10.7 cm solar flux, this is not reflected to such an extent in the occurrence of frictional heating. It is suggested that this is a consequence of the decreased neutral atmosphere response times associated with active solar conditions, resulting from the higher ionospheric plasma densities present. Seasonal effects on the diurnal distribution of ion frictional heating are well explained by corresponding variations in ionospheric convection, the latter principally a result of geometrical factors. It is noted that, over the entire dataset, the variations in the unperturbed F-region ion temperature, required to implement the identification criterion for ion heating, are highly correlated with model values of thermospheric temperature.Keywords. Ionosphere (auroral ionosphere; ionosphere-atmosphere interactions; plasma temperature and density)
A mode filter for plasma waves in the Hall-MHD approximation
Authors: Vocks C. , Motschmann U. , Glassmeier K.-H.
Published: June 2005

Abstract. A filter method is presented which allows a qualitative and quantitative identification of wave modes observed with plasma experiments on satellites. Hitherto existing mode filters are based on the MHD theory and thus they are restricted to low frequencies well below the ion cyclotron frequency. The present method is generalized to cover wave modes up to the characteristic ion frequencies. The spectral density matrix determined by the observations is decomposed using the eigenvectors of the linearized Hall-MHD equations. As the wave modes are dispersive in this formalism, a precise determination of the k->-vectors requires the use of multi-point measurements. Therefore the method is particularly relevant to multi-satellite missions. The method is tested using simulated plasma data. The Hall-MHD filter is able to identify the modes excited in the model plasma and to assign the correct energetic contributions. By comparison with the former method it is shown that the simple MHD filter leads to large errors if the frequency is not well below the ion cyclotron frequency. Further the range of validity of the linear theory is examined rising the simulated wave amplitudes.Key words. Magnetospheric physics (MHD waves and instabilities; plasma waves and instabilities)
INTERBALL-Auroral observations of 0.1-12 keV ion gaps in the diffuse auroral zone
Authors: Kovrazhkin R. A. , Sauvaud J.-A. , Delcourt D. C.
Published: June 2005

Abstract. We examine ion flux dropouts detected by INTERBALL-Auroral upon traversal of the auroral zone at altitudes of \\sim13 000 up to 20 000 km. These dropouts which we refer to as "gaps", are frequently observed irrespectively of longitudinal sector and appear characteristic of INTERBALL-Auroral ion spectrograms. Whereas some of these gaps display a nearly monoenergetic character (~12 keV), others occur at energies of a few hundreds of eV up to several keV. INTERBALL-Auroral data exhibit the former monoenergetic gap variety essentially in the evening sector. As examined in previous studies, these gaps appear related to transition from particle orbits that are connected with the magnetotail plasma source to closed orbits encircling the Earth. The latter gap variety, which spreads over several hundreds of eV to a few keV is often observed in the dayside magnetosphere. It is argued that such gaps are due to magnetospheric residence times well above the ion lifetime. This interpretation is supported by numerical orbit calculations which reveal extremely large (up to several tens of hours) times of flight in a limited energy range as a result of conflicting E × B and gradient-curvature drifts. The characteristic energies obtained numerically depend upon both longitude and latitude and are quite consistent with those measured in-situ.Key words. Magnetospheric physics (auroral phenomena; plasma convection)
ULF wave occurrence statistics in a high-latitude HF Doppler sounder
Authors: Wright D. M. , Yeoman T. K. , Jones T. B.
Published: June 2005

Abstract. Ultra low frequency (ULF) wave activity in the high-latitude ionosphere has been observed by a high frequency (HF) Doppler sounder located at Tromsø, Norway (69.7°N, 19.2°E geographic coordinates). A statistical study of the occurrence of these waves has been undertaken from data collected between 1979 and 1984. The diurnal, seasonal, solar cycle and geomagnetic activity variations in occurrence have been investigated. The findings demonstrate that the ability of the sounder to detect ULF wave signatures maximises at the equinoxes and that there is a peak in occurrence in the morning sector. The occurrence rate is fairly insensitive to changes associated with the solar cycle but increases with the level of geomagnetic activity. As a result, it has been possible to characterise the way in which prevailing ionospheric and magnetospheric conditions affect such observations of ULF waves.Key words. Ionosphere (auroral ionosphere; ionosphere -magnetosphere interactions) · Magnetospheric physics (MHD waves and instabilities)