bluuebunny/crossref_metadata_2025 huggingface dataset:
Classical bremsstrahlung radiation from
electron–ion encounters in a nonideal plasma
Authors: JUNG YOUNG-DAE , KIM CHANG-GEUN
Published: October 2003

The classical electron–ion Coulomb bremsstrahlung process is investigated in a nonideal plasma. An effective pseudopotential model taking into account
plasma-screening and collective effects is applied to describe the electron-ion interaction potential in a nonideal plasma. The screened hyperbolic-orbit trajectory
method is applied to the motion of the projectile electron in order to investigate
the bremsstrahlung radiation cross-section as a function of the scaled impact
parameter, eccentricity, nonideal-plasma parameter, Debye length, projectile
energy, and photon energy. It is found that the collective effect reduces the bremsstrahlung radiation cross-section on both the soft- and hard-photon cases. For small
impact parameters, the nonideal-plasma effect on the bremsstrahlung radiation
cross-section is found to be quite small. It is also found that the maximum position of the bremsstrahlung radiation cross-section gets closer to the target ion with
increasing nonideal-plasma effect.
A class of resistive axisymmetric
magnetohydrodynamic equilibria in a
periodic cylinder
Authors: PONNO ANTONIO , GALGANI LUIGI , MONTGOMERY DAVID C.
Published: October 2003

We consider a model of viscoresistive incompressible magnetohydrodynamics in a periodic cylinder, with boundary conditions meant to idealize in
a tractable way those of a laboratory plasma. The resistivity is described by a
tensor presenting a field-dependent anisotropic part suggested by kinetic theory,
controlled by a certain anisotropy parameter. An explicit analytical description
of the corresponding axisymmetric zero-flow equilibria is given, and it is shown
how tokamak-like or paramagnetic-pinch-like field profiles are obtained as the
anisotropy parameter is changed. The study of the stability properties of such
equilibria is deferred to a later paper.
Meromorphy and topology of localized solutions in the Thomas–MHD model
Authors: FOURNIER J.-D. , GALTIER S.
Published: October 2003

The one-dimensional MHD system first introduced by J.H. Thomas [Phys.
Fluids 11, 1245 (1968)] as a model of the dynamo effect is thoroughly studied in
the limit of large magnetic Prandtl number. The focus is on two types of localized solutions involving shocks (antishocks) and hollow (bump) waves. Numerical
simulations suggest phenomenological rules concerning their generation, stability
and basin of attraction. Their topology, amplitude and thickness are compared
favourably with those of the meromorphic travelling waves, which are obtained
exactly, and respectively those of asymptotic descriptions involving rational
or degenerate elliptic functions. The meromorphy bars the existence of certain
configurations, while others are explained by assuming imaginary residues. These
explanations are tested using the numerical amplitude and phase of the Fourier transforms
as probes of the analyticity properties. Theoretically, the proof of the partial integrability
backs up the role ascribed to meromorphy. Practically, predictions are
derived for MHD plasmas.
Numerical simulation of the excitation and evolution of high-azimuthal-mode-number
coherent vortices in hollow magnetized electron columns
Authors: MARCHAND R. , SHOUCRI M.
Published: October 2003

A finite-element code is used to study the excitation of a perturbation
with a range of azimuthal mode numbers in hollow magnetized plasma columns,
and the subsequent nonlinear development and evolution of coherent vortices
interacting to coalesce, while cascading to a lower azimuthal mode number. It
is shown that, even for initially higher azimuthal mode numbers, the angular
momentum remains a slowly varying ideal invariant, while the system cascades
to lower azimuthal mode numbers. A detailed study of the evolution is
presented for initially excited m = 3, m = 4, and m = 5 azimuthal modes, which
underlines the physics of the inverse cascade of angular momentum.
Impossibility of Zakharov's short-wavelength
modulational instability in plasmas with
intense Langmuir turbulence
Authors: EROFEEV V. I.
Published: October 2003

An analysis of two experimental observations of Langmuir wave collapse
is performed. The corresponding experimental data are shown as evidence against
the occurrence of collapses. The physical reason preventing the collapses is found
to be the nonresonant electron diffusion in momentum. In this process, plasma
thermal electrons are efficiently heated at the expense of wave energy, therefore
intense collisionless wave dissipation takes place. The basic reason for the
underestimation of nonresonant electron diffusion in the traditional theory is shown to be
the substitution of a real plasma by a plasma probabilistic ensemble.

A study of nonresonant electron diffusion refraining from ensemble substitution
is performed. It is shown that its intensity is sufficient for suppression of Zakharov's
short-wavelength modulational plasma instability [Zakharov, V. E., Sov.
Phys. JETP35, 908 (1972)]. This explains the nonoccurrence of Zakharov's Langmuir
wave collapse in experiments.
Electron acoustic–Langmuir solitons in a two-component electron plasma
Authors: McKENZIE J. F.
Published: October 2003

We investigate the conditions under which ‘high-frequency’ electron acoustic–Langmuir solitons can be constructed in a plasma consisting of protons and two electron populations: one ‘cold’ and the other ‘hot’. Conservation of total momentum can be cast as a structure equation either for the ‘cold’ or ‘hot’ electron flow speed in a stationary wave using the Bernoulli energy equations for each species. The linearized version of the governing equations gives the dispersion equation for the stationary waves of the system, from which follows the necessary – but not sufficient – conditions for the existence of soliton structures; namely that the wave speed must be less than the acoustic speed of the ‘hot’ electron component and greater than the low-frequency compound acoustic speed of the two electron populations. In this wave speed regime linear waves are ‘evanescent’, giving rise to the exponential growth or decay, which readily can give rise to non-linear effects that may balance dispersion and allow soliton formation. In general the ‘hot’ component must be more abundant than the ‘cold’ one and the wave is characterized by a compression of the ‘cold’ component and an expansion in the ‘hot’ component necessitating a potential dip. Both components are driven towards their sonic points; the ‘cold’ from above and the ‘hot’ from below. It is this transonic feature which limits the amplitude of the soliton. If the ‘hot’ component is not sufficiently abundant the window for soliton formation shrinks to a narrow speed regime which is quasi-transonic relative to the ‘hot’ electron acoustic speed, and it is shown that smooth solitons cannot be constructed. In the special case of a very cold electron population (i.e. ‘highly supersonic’) and the other population being very hot (i.e. ‘highly subsonic’) with adiabatic index 2, the structure equation simplifies and can be integrated in terms of elementary transcendental functions that provide the fully non-linear counterpart to the weakly non-linear sech$^{2}$-type solitons. In this case the limiting soliton is comprised of an infinite compression in the cold component, a weak rarefaction in the ‘hot’ electrons and a modest potential dip.
Reassessing Indirect Rule in Hyderabad: Rule, Ruler, or Sons-in-Law of the State?
Authors: Leonard Karen
Published: October 2003

Those of us who work on the Indian princely states sometimes seem to share a certain marginalization, a certain
distance from the debates shaping the writing of South Asian history today. We also share, more positively, views
of that history that do not focus on British colonial rule and are not based on colonial sources, views that arguably
offer more continuity with pre-British history and alternative visions of the South Asian past, present, and future.
Verheißung und Erfüllung im Lichte paulinischer Theologie
Authors: SÖDING THOMAS
Published: October 2003

Paul is the first author of the NT who stresses the central biblical-theological theme of ‘promise and fulfilment’. He is doing so as apostle of the righteousness of God: the One God remains true to Himself as the ‘God of hope’ (Rom 15.13); sending His son to save the world of sinners He says his ‘Yes’ to all He has given in His grace to His people (2 Cor. 1.20), and He creates the eschatological act of redemption which is radically new in opening the Kingdom of God (Rom 14.17). In the horizon of his theology of justification, Paul discovers what God has promised to Abraham; in the horizon of his theology of promise, he discovers what God fulfils in justifying Jews and Gentiles by their faith. Paul's theology, maturing from Galatians to Romans, gives a good measure for Christian talk of promise and fulfilment in dialogue with the Jews.
‘Impregnable Ramparts and Walls Of Iron’: Boundary and Identity in Early ‘Judaism’ and ‘Christianity’
Authors: LIEU JUDITH
Published: October 2003

The metaphor of a boundary as that which separates ‘us’ from ‘the other’ is central in modern discussion of identity as constructed, yet it is also recognized that such boundaries both articulate power and are permeable. The model is readily applicable to the Greco-Roman world where kinship, history, language, customs, and the gods supposedly separated ‘us’ from barbarians, but also enabled interaction; Jews and Christians engaged in the same strategies. At the textual level it is the different ways in which boundaries are constructed, particularly using diet and sexuality, that invite attention. This may offer a way of addressing questions of unity and diversity, of Judaism versus Judaisms, and of how ‘Christianity’ emerges as separate from ‘Judaism’.
Animal models of intestinal nematode infections of humans
Authors: BOES J. , HELWIGH A.B.
Published: October 2003

In this paper we discuss several established and potential animal models for human parasitic infection, with a focus on rodent, pig and primate models and the nematodes Ascaris, Trichuris and Toxocara spp. Firstly, we discuss the relevance of choosing a suitable animal host to fit the particular study hypothesis, and the interaction between mathematical modelling and animal models. Secondly, we review the use of animal models for the study of nutrition-parasite interaction, evaluation of treatment and control strategies, and bacteria-parasite interactions. We show that rodent, pig and primate models are all very useful in parasitological research, and that each model has its limitations. However, based on recent experience with the pig-Ascaris and pig-Trichuris models, a more extensive use of the pig-parasite model is advocated, especially for the study of the interaction between human malnutrition and helminth infection, and congenital helminth infection.
Myxosporidia and macrophage centres in chub (Leuciscus cephalus)–quantitative interactions focus on Myxobolus cyprini
Authors: HOLZER A.S. , SCHACHNER O.
Published: October 2003

Six myxosporidian species were found in chub (Leuciscus cephalus) originating from Lower Austrian rivers. The frequency of the parasites and their localization was recorded. In all chub, independent of size and origin, Myxobolus cyprini occurred predominantly in the macrophage centres (MCs) of the haematopoietic organs, spleen and kidney. Exclusively in the head kidney of young fish not yet described vermicular plasmodia containing spores of M. cyprini were found. In muscle tissue the prevalence of M. cyprini was comparatively low. Other species of Myxobolus characterized by plasmodial cysts frequently occurred in gills and swimbladder but were rarely detected, and only in small numbers, in the haematopoietic organs. The number of M. cyprini spores and the relative volume of MCs in the haematopoietic organs were estimated in order to examine possible correlations. Significant interrelated changes were found only in juvenile fish up to a size of 15cm. In bigger fish, the number and size of macrophage aggregates were highly variable and independent of infection intensity and fish size, but the number of spores never exceeded that of the aggregated macrophages. The data suggest that due to an early date of infection M. cyprini is the only species which is closely associated with macrophage aggregation.
Monogenean community structure on the gills of Pimelodus albicans from Río de la Plata (Argentina): a comparative approach
Authors: GUTIÉRREZ P. A.
Published: October 2003

The community structure of monogeneans on the gills of a catfish Pimelodus albicans, in the Río de la Plata, was studied and compared with previous findings on P. maculatus. Six Monogenea species belonging to 3 genera were found: Demidospermus majusculus Kritsky & Gutiérrez, 1998; Demidospermus armostus Kritsky & Gutiérrez, 1998; Demidospermus idolus Kritsky & Gutiérrez, 1998; Demidospermus bidiverticulatum (Suriano & Incorvaia, 1995) Kritsky & Gutiérrez, 1998; Scleroductus yuncensi Jara & Cone, 1989; and Unibarra paranoplatensis Suriano & Incorvaia, 1995. The relationships between selected host and helminth variables; the interactions between the worms and the patterns obtained from the species abundance were analysed employing appropriate statistical methodology. The results obtained revealed the following common patterns within the monogenean communities of P. maculatus and P. albicans: (a) most monogenean species belonged to the genus Demidospermus; (b) S. yuncensi was a secondary species in both communities; (c) 1 of the 3 species common to both hosts was a core species (D. bidiverticulatum); (d) the selected variables of both hosts (weight and length) were not related to the number of monogeneans or species richness; (e) the dominant species in both communities showed the highest proportion of monogeneans in more than 40 % of the infracommunities; (f ) in both communities the dominant species accounted for 40–80 % of the total number of monogeneans at component community level; (g) the number of worms correlates positively with the species richness; (h) few cases of interaction among species were found; (i) a high degree of order exists among the infracommunities compared. Finally, the proportion of common species and the phylogenetic and ecological resemblances between the hosts, P. maculatus and P. albicans support a hypothesis of co-speciation among monogeneans and pimelodids in Río de la Plata. It seems improbable that these parasite communities are recent species assemblages formed by chance. The phylogenetic resemblance of the host–monogeneans system in Río de la Plata suggests that there is a single community pattern that can be observed in congeneric and sympatric hosts.
Nuclear DNA sequence specific to Leishmania (Viannia) subgenus: a molecular marker for species identification
Authors: LUIS L. , RAMÍREZ A. H. , RAMÍREZ R. , VÉLEZ I. D. , MENDOZA-LEÓN A.
Published: October 2003

As shown by RFLP analysis, there is a high variability in the β-tubulin gene region of Leishmania sp. Such variability has been used in the identification of these parasites, establishing differences between subgenera of New World Leishmania. We have found a region of 500 bp (β500) upstream of the coding region of the β-tubulin gene that is present in all strains tested belonging to the L. (Viannia) subgenus. This region apparently is a repetitive sequence and we have shown that it is specific to the Leishmania (Viannia) subgenus. This sequence has no homology with the genomic DNA isolated from either the species belonging to the L. (Leishmania) subgenus or other Kinetoplastida, such as Trypanosoma cruzi, T. brucei, Leptomonas samueli, or Crithidia fasciculata. The β500 sequence showed sufficient variation to be used as a molecular marker in the identification of parasites. We established inter- and intrasubgenus differentiation and were able to discriminate at the species level in the Vianna subgenus. A PCR assay confirmed the specificity of the β500 sequence.
Construction and validation of a polycompetitor construct (SWITCH) for use in competitive RT-PCR to assess tachyzoite-bradyzoite interconversion in Toxoplasma gondii
Authors: LYONS R. E. , LYONS K. , McLEOD R. , ROBERTS C. W.
Published: October 2003

The obligate intracellular protozoan parasite, Toxoplasma gondii exists as 2 life-cycle forms in intermediate hosts. The rapidly dividing tachyzoites responsible for acute disease, present in the first 14 days of infection, give rise to slowly dividing bradyzoites that reside in tissue cysts. Reactivation of disease is associated with conversion of bradyzoites to tachyzoites. A sensitive method for detection and assessment of the number of each life-cycle stage would be useful for following these events. Herein we describe the construction and validation of a plasmid (pSWITCH) containing a polycompetitor construct (SWITCH) for use in competitive reverse transcriptase-PCR (cRT-PCR). pSWITCH contains competitors for SAG2A and LDH2 genes, which are exclusively expressed by tachyzoite and bradyzoite stages respectively, and for β-tubulin, a gene expressed by both stages. Using cRT-PCR, samples can first be accurately normalized for expression of the housekeeping gene, β-tubulin and then the relative levels of SAG2A and LDH2 expression compared to follow stage conversion. The abundance of transcripts for other genes of interest can then be followed during this process as demonstrated here for the SAG2-related family of genes. This technique offers a powerful tool for studying the processes involved in tachyzoite and bradyzoite interconversion.
The attachment of Schistosoma mansoni cercariae to human skin cells
Authors: KHAMMO N. , BARTLETT A. , CLOTHIER R. H. , WHITFIELD P. J.
Published: October 2003

Most of our knowledge about the process of penetration of skin, by cercariae of Schistosoma mansoni, has been gained from studies carried out in vivo with laboratory animals. Human skin is significantly different from that of other animals but there are obvious practical difficulties in directly studying attachment and penetration with human skin. Techniques have been developed which enable a 3-dimensional ‘skin equivalent’ to be grown in tissue culture, made from different types of human skin cells. The aim of the present study was to investigate cercarial interactions with confluent cultures of the individual skin cell types that make up normal human skin and which will be used to construct a multi-component model. Cercariae behaved differently towards the various cell types tested. They responded least to monolayers of endothelial cells and most to primary keratinocytes, derived from human foreskin and differentiated at an air/liquid interface. This study demonstrates, therefore, that cercariae are capable of distinguishing between different types of skin cells and they preferentially attach to differentiated cells which form the epidermis.
Infection and transformation of dendritic cells from bovine afferent lymph by Theileria annulata
Authors: STEPHENS S. A. , HOWARD C. J.
Published: October 2003

Following incubation with sporozoites of the protozoan parasite Theileria annulata, dendritic cells (DC), extracted from bovine afferent lymph, became infected and transformed into large, rounded, continuously proliferating cell lines. Phenotypic analysis of the transformed cells by immunostaining and flow cytometry revealed that they expressed MHC class I and II antigens, the myeloid marker MyD1 (SIRPα) and the bovine WC6 (workshop cluster 6) molecule. Transformed DC cell lines differed from those produced from infection of macrophages and B cells in that some lines expressed CD21 and a proportion of cells continued to express the antigen stained by the mAb CC81, a marker which defines a subpopulation of DC in afferent lymph. Both of the main populations of DC that have been identified in bovine afferent lymph appeared to be equally permissive for infection and transformation with T. annulata. These findings raise the possibility that the transformed proliferating cells characteristic of in vivo infections could be derived from DC as well as macrophages. This could have consequences for understanding the pathogenesis of the disease and for developing methods to manipulate immune responses to eliminate the parasite.
Efficacy of oryzalin and associated histological changes in Cryptosporidium-infected neonatal rats
Authors: ARMSON A. , MENON K. , O'HARA A. , MACDONALD L. M. , READ C. M. , SARGENT K. , THOMPSON R. C. A. , REYNOLDSON J. A.
Published: October 2003

This paper reports the anti-cryptosporidial effects of, and concomitant amelioration of the histological changes in the gut of neonatal rats with intestinal cryptosporidiosis treated with the dinitroaniline, oryzalin. The ED50 was determined to be 7 mg/kg using twice daily doses administered for 3 consecutive days. A maximum inhibition of 85.5% was achieved at 25 mg/kg and this inhibition remained constant despite increasing the oryzalin dose to 200 mg/kg. Cryptosporidiosis significantly decreased the intestinal villus/crypt (VC) ratio by approximately 50% (duodenum = 2.3, jejunum = 2.5 and ileum = 1.7) when compared to uninfected untreated controls (duodenum = 4.3, jejunum = 5.9 and ileum = 4.5). Treatment with oryzalin doubled the VC ratio in the duodenum, jejunum and ileum following doses of 5 mg, 50 mg and 200 mg/kg respectively. Oryzalin concentrations in the small intestine contents and plasma were determined, using HPLC, at 0.5, 1 and 2 h after dosing. The much greater dose required to return VC ratios to normal in the ileum (200 mg/kg) compared to the duodenum (6.25 mg/kg) appeared to reflect the decreased concentration of the drug in the distal small intestine. Concentrations of oryzalin equivalent to the in vitro IC50 were maintained for 2 h in the first half of the small intestine following a single dose of 100 mg/kg.
The impact of a vertically transmitted microsporidian, Nosema granulosis on the fitness of its Gammarus duebeni host under stressful environmental conditions
Authors: KELLY A. , HATCHER M. J. , DUNN A. M.
Published: October 2003

Although purely vertically transmitted parasites are predicted to cause low pathogenicity in their hosts, the effects of such parasites on host fitness under stressful environmental conditions have not previously been assessed. Here, we investigate the effects of Nosema granulosis, a vertically transmitted, microsporidian parasite of the brackish water amphipod Gammarus duebeni, on host growth and survival under conditions of host–host competition and limited food. The parasite had no effect on host survival, but caused a reduction in juvenile growth. Stressful environmental conditions also led to a reduction in G. duebeni growth. However, we found no evidence to support the prediction that parasitized hosts would suffer a greater reduction in fitness than uninfected hosts under adverse environmental conditions. We interpret our results in the context of selection for successful vertical parasite transmission.
The effects of host immunity on virulence–transmissibility relationships in the rodent malaria parasite Plasmodium chabaudi
Authors: MACKINNON M. J. , READ A. F.
Published: October 2003

Here we examined the impact of host immunity on relationships between parasite virulence, transmission rate, intrinsic growth rate and host recovery rate in the rodent malaria parasite, Plasmodium chabaudi. Groups of naïve and immunized mice were infected with 1 of 10 cloned lines of parasites and their infection dynamics were monitored for 19 days. We found that (1) host immunity reduced the growth rate, virulence, transmission rate and infection length, with a consequent 3-fold reduction in life-time transmission potential, (2) clone means for these traits ranked similarly across naïve and immunized mice, (3) regression slopes of transmission potential on growth rate, virulence and infection length were similar in naïve and immunized mice, (4) virulence and infection length were positively correlated in immunized but not naïve mice, and (5) for a similar level of parasite growth rate and virulence, transmission potential and infection length were lower in immunized than naïve mice. Thus host immunity reduced all these fitness traits in a manner consistent with direct parasite-driven biological links among them. These results support the basic assumption underlying our theory that predicts that anti-disease vaccines will select for higher virulence in those microparasites for which virulence is integrally linked to transmission.
Genetic differentiation in populations of the cestode Bothriocephalus acheilognathi (Cestoda, Pseudophyllidea) as revealed by eight microsatellite markers
Authors: LUO H. Y. , NIE P. , ZHANG Y. A. , YAO W. J. , WANG G. T.
Published: October 2003

The genetic structure of populations of the fish cestode, Bothriocephalus acheilognathi collected from Bailianhe Reservoir (BLH), Changshou (CSH) and Liangzi (LZH) Lakes was investigated by using 8 microsatellite loci. A total of 108 adult worms were genotyped at each of the 8 loci. For the 3 populations, the mean number of alleles per locus ranged from 2·38 to 5·5, and the mean expected heterozygosity ranged from 0·432 to 0·559. The average polymorphic information content (PIC) was from 0·384 to 0·492. The significant Fis values indicated non-random mating within LZH and BLH populations. On the other hand, when samples were further classified into subpopulations at the level of host fish species, no or little heterozygote deficiency was detected at most loci, showing that cross-fertilization, predominantly, but not exclusively, must have occurred within the subpopulations. Microsatellite markers also revealed an unexpected high level of genetic differentiation, as measured by Rst and Nm values or by δu2 genetic distance among subpopulations from different hosts. Factors influencing the population genetic structure and the parasite host specificity are discussed.
Constraint, Empowerment, and Guidance: A Conjectural Classification of Laws of Nature
Authors: Hodgson David
Published: October 2003

This paper introduces a conjecture that laws of nature may be of different kinds, in particular that there may, in addition to laws which constrain outcomes (C-laws), be laws which empower systems to direct or select outcomes (E-laws) and laws which guide systems in such selections (G-laws). The paper defends this conjecture by suggesting that it is not excluded by anything we know, is plausible, and is potentially of great explanatory power.
Deepening the Controversy over Metaphysical Realism
Authors: Allen Sophie R.
Published: October 2003

A significant ontological commitment is required to sustain metaphysical realism—the view that there is a single, objective way the world is—in order to defend it from common sense objections. This involves presupposing the existence of properties (or tropes, or universals) and relations between them which define the objective structure of the world. This paper explores the grounds for accepting this ontological assumption and examines a sceptical argument which questions whether, having assumed the world is objectively divided into fundamental properties, we could ever know which properties these are. It then assesses the responses available to the metaphysical realist, arguing that the sceptical difficulty cannot merely be dismissed by means of another assumption in the manner of radical scepticism, as David Lewis suggests, but that the sceptic's argument might be defused by the non-question-begging success of some form of strong scientific realism which links the predicates of our scientific theories directly to the fundamental properties the world contains. It remains unclear however whether this widely accepted metaphysical theory can find principled philosophical support.
Photography in the Arctic, 1876–84: the work of W.J.A. Grant
Authors: Mörzer Bruyns Willem F.J.
Published: October 2003

In recent years, pioneer photographers in the Arctic have been researched. The last was W.J.A. Grant, who sailed as a photographer with Sir Allen Young in Pandora in 1876. Grant made another seven photographic trips to the Arctic. Four voyages were in the Dutch Arctic schooner Willem Barents, the others in British yachts. Grant's photographic legacy is considerable, but little known. The majority of his work was done for the Dutch and is still preserved in the Netherlands. Recently it has been possible to identify photographs by Grant in British collections. This article examines Grant and his work as an Arctic photographer.
Effect of nutrient enrichments on the bacterial assemblage of Antarctic soils contaminated by diesel or crude oil
Authors: Delille D. , Pelletier E. , Delille B. , Coulon F.
Published: October 2003

There is an urgent need to develop new technologies to address the problem of soil remediation in high-latitude regions. A field study was initiated in January 1997 in two contaminated soils in Terre Adélie (Antarctica) with the objective of determining the long-term effectiveness of two bioremediation agents on total and hydrocarbon-degrading microbial assemblages under severe Antarctic conditions. This study was conducted in two steps, from January to July 1997 and from February to November 1999 in the Géologie Archipelago (Terre Adélie, 66°40′S, 140°01′E). Changes in bacterial communities were monitored in situ after crude oil or diesel addition in a series of 600 cm2 soil sectors (20×30 cm). Four contaminated sectors were used for each experiment: diesel oil (10 ml), diesel oil (10 ml) + fertilizer (1 ml), Arabian light crude oil (10 ml), and crude oil (10 ml) + fertilizer (1 ml). Two different bioremediation agents were used: a slow release fertilizer Inipol EAP-22 (Elf Atochem) in 1997 and a fish compost in 1999. Plots were sampled on a regular basis during a three-year period. All samples were analysed for total, saprophytic psychrophilic, and hydrocarbon-utilising bacteria. A one order of magnitude increase of saprophytic and hydrocarbon-utilising micro-organisms occurred during the first month of the experiment in most of the contaminated enclosures, but no clear differences appeared between fertilized and unfertilized plots. Diesel-oil contamination induced a significant increase of all bacterial parameters in all contaminated soils. Crude-oil contamination had no clear effects on microbial assemblages. It was clear that the microbial response could be rapid and efficient in spite of the severe weather conditions. However, microbial growth was not clearly improved in the presence of bioremediation agents.
Peel-Caribou Staging Area, Yukon Territory: assessment and remediation of DDT and other contaminants along a riverbank
Authors: Dodd Matt , Hartshorne Brett , Liebau Werner , Seaman Rick
Published: October 2003

The Peel-Caribou Staging Area, located along the Peel River, northern Yukon Territory, was used for exploratory drilling activities during the mid-1960s. Following abandonment of the project in 1975, waste materials were buried in a pit on site. An encroachment of the river on the waste pit in 1994 exposed the debris along with soils contamiated by DDT (1,1,1-trichloro-2,2-bis-(4-chlorophenyl)ethane), metals, hydrocarbons, and dichloromethane. The results of subsurface drilling in April 2000 and contaminants analyses, along with data from a geophysical investigation, indicated contaminated soils and debris were located in a 2-metre thick layer below the high-water mark of the riverbank, with an overburden of soil varying in depths from 3 to 4 m. The validation of various field test kits — including immunoassay test kits, PetroFLAGTM analyzer, and photoionization detector — as possible analytical tools for on-site testing was conducted during the site investigations. Site remediation was conducted in January–March 2002 while the river was frozen to facilitate excavations along the frozen and exposed riverbank as well as site access. The debris along the riverbank is usually submerged in the summer and autumn due to fluctuating water levels. Following the construction of a winter overland route to the site, the contaminated soils and associated waste were excavated and transported off-site for disposal. Based on the validation exercise, immunoassay test kits were used for on-site delineation and confirmatory testing during site remediation.
A comparative biogeochemical study of sediments from Kandalaksha Bay, White Sea, Russian Arctic
Authors: Koukina Sofia , Korneeva Galina , Ametistova Lioudmila , Bek Tatiana
Published: October 2003

Major (Al, Fe), minor (Mn), and trace (Li, Cu, Ni, Cr, Cd, Zn, Pb) metals along with nutrients (TOC, TON, TS, TP) and enzymatic activities were determined in 18 surface sediment and two soil samples collected in six small bays of the Karelian shore of Kandalaksha Bay, White Sea, Russian Arctic. The studied sediments tended to be marine, with a major input of organic matter from autochthonous sources. Marine organic material might be an important carrier of trace metals in the examined sediments. According to sediment quality guidelines, all trace-metal contents were below the threshold levels. The results of azocasein-trypsin tests also suggested no significant contamination of analysed sediments and soils. A comparison of the trace-metal contents in the sediments examined with those of the western Arctic shelf showed higher levels of Zn and Cr in the Karelian shore. Presumably these disparities were related to regional differences in sediment chemistries rather than to any enhanced pollution within the studied area. Both geochemical composition and enzymatic-activities patterns among sites studied are largely controlled by the sediment granulometry. The evolution of sediments in the restricted exchange environments under investigation is caused by depositional conditions, which are strongly affected by small-scale hydrodynamic processes specific for each particular area. The most vivid examples are separating basins, where the fine-grained sediments enriched in organic matter — and thus in nutrients and metals — are formed under calm hydrodynamic conditions enhanced by severely restricted water exchange.
Conducting environmental analyses at remote sites in cold climates
Authors: Rutter Allison , Cairns Graham , Plato Natalie , Poland John S.
Published: October 2003

Clean-up sites in cold climates present unique challenges for the analytical chemist, primarily because of transportation constraints and limited infrastructure. Excavation of chemically contaminated soils and dumps requires a quick turnaround for analytical results. This is mainly due to the cost factors involved in having expensive heavy equipment idle and the short working seasons, but also because of melting of exposed permafrost during excavation. Three options are available for conducting analyses at remote polar sites. These are off-site determinations, the use of on-site test kits (or simple procedures), and the deployment of a mobile laboratory. This paper discusses these options and provides details of available on-site techniques as well as specific examples of their application in remote northern sites. The design and operation of a mobile laboratory at Resolution Island, Nunavut, is described, and available test kits are compiled and reviewed.
The Third International Conference on Contaminants in Freezing Ground, Hobart, Tasmania, 14–18 April 2002
Authors: Snape Ian
Published: October 2003

The International Conferences on Contaminants in Freezing Ground are organised under the auspices of an International Steering Committee to promote a better understanding of the unique characteristics and problems posed by contaminants in freezing ground. The first meeting was held in Cambridge in 1997 and was attended by 33 participants from nine countries. Results from the meeting were reported in Polar Record in 1998 (volume 35). The themes covered at the first meeting reflected a broad range of interests, including a synthesis of the Arctic environmental strategy as it stood in 1997; the fundamental physical, chemical, and biological properties of contaminated frozen soils; experimental approaches to determining contaminant movement; and possibilities for in situ bioremediation of petroleum spills.
Obituary
Authors: Hattersley-Smith Geoffrey
Published: October 2003

Walter George Richards, who died in Stanley, Falkland Islands, in October 2002 aged 73, served as a ‘handyman’ with the Falklands Islands Dependencies Survey from 1948 to 1950. He was long known by his nickname ‘Bill.’
Somatic distress syndromes in later life: the need for paradigm change
Authors: WIJERATNE CHANAKA , HICKIE IAN
Published: October 2003

Somatic distress syndromes, which include somatoform disorders and syndromes of chronic
fatigue such as neurasthenia but not somatic presentations of anxiety and depression, are one of the
common expressions of distress in primary care (Ormel et al. 1994) and general hospital settings
(Hemert et al. 1993). They are of considerable importance cross-culturally (Ono et al. 1999), and
often lie at the interface of psychiatry and medicine (Hickie, 1999). They are associated with
significant disability (Ormel et al. 1994; Andrews, 2000) and health-care utilization (Escobar et al.
1991).
Dysphoria: self-devaluative and affective components in recovered depressed patients and never depressed controls
Authors: TEASDALE JOHN D. , COX SALLY G.
Published: October 2003

Background. The Interacting Cognitive Subsystems analysis of cognitive vulnerability to depression predicts that subjective experiences of dysphoria in recovered depressed patients will be qualitatively different from those of controls. This study tested this prediction using a new instrument, the Depressed States Checklist.

Methods. Twenty-three recovered recurrently depressed patients and 54 never depressed controls rated the affective and self-devaluative components of a dysphoric experience.

Results. Groups reported similar levels of affective component but recovered depressed patients reported higher self-devaluative dysphoric experience. At zero affective component of dysphoria neither group reported any self-devaluative feelings. With increasing affective component of dysphoria, the self-devaluative component increased significantly more in recovered patients than in controls. The ratio of self-devaluative to affective components of dysphoria significantly differentiated recovered depressed patients from controls.

Conclusions. As predicted, dysphoria in recovered depressed patients is qualitatively different from controls in ways that increase vulnerability to major depression. The Depressed States Checklist is a new, brief, measure of cognitive vulnerability to depression that may be particularly useful in large, prospective, epidemiological studies.
Persecutory delusions: developing the understanding of belief maintenance and emotional distress
Authors: FREEMAN D. , GARETY P. A. , KUIPERS E.
Published: October 2003

Background. The objective of the study was to develop the cognitive understanding of persecutory delusions. It was hypothesized that safety behaviours contribute to the persistence of persecutory delusions by preventing disconfirmation. It was further hypothesized that emotional distress is associated with aspects of the content of delusions. An investigation was designed to establish whether individuals with persecutory delusions use safety behaviours, and to test predicted associations between delusion content and emotional distress.

Method. A cross-sectional investigation was conducted on 25 individuals with persecutory delusions. A detailed assessment was made of the presence of safety behaviours, the content of delusions and emotional distress.

Results. All participants had used at least one safety behaviour in the last month, most typically avoidance. Higher levels of anxiety were associated with greater use of safety behaviours. New data were obtained on the content of persecutory delusions. Aspects of the content of the delusions were associated with levels of depression, self-esteem, anxiety and delusional distress.

Conclusions. Individuals with persecutory delusions use safety behaviours. The findings may develop the understanding of delusion persistence, acting upon delusions and the negative symptoms of schizophrenia. There are implications for cognitive interventions for psychosis. Support was also found for the hypothesis that emotional distress is linked to the content of delusional beliefs; it is speculated that prior emotional distress influences the content of delusions, and that delusion content in turn influences levels of emotional distress.
Diagnostic outcome of self-reported hallucinations in a community sample of adolescents
Authors: DHOSSCHE D. , FERDINAND R. , VAN DER ENDE J. , HOFSTRA M. B. , VERHULST F.
Published: October 2003

Objective. We aimed to assess the diagnostic outcome of self-reported hallucinations in adolescents from the general population.

Method. The sample consisted of 914 adolescents between ages 11–18 participating in an ongoing longitudinal study. The participation rate from the original sample was 70%. Responses on the Youth Self-Report questionnaire were used to ascertain hallucinations in adolescents. Eight years later, Axis 1 DSM-IV diagnoses were assessed using the 12-month version Composite International Diagnostic Interview in 783 (86%) of 914 study subjects. No subjects were diagnosed with schizophreniform disorders or schizophrenia.

Results. Hallucinations were reported by 6% of adolescents and 3% of young adults. Self-reported hallucinations were associated with concurrent non-psychotic psychiatric problems in both age groups. Adolescents who reported auditory, but not visual, hallucinations, had higher rates of depressive disorders and substance use disorders, but not psychotic disorders, at follow-up, compared to controls.

Conclusions. Self-reported auditory hallucinations in adolescents are markers of concurrent and future psychiatric impairment due to non-psychotic Axis 1 disorders and possibly Axis 2 disorders. It cannot be excluded that there was selective attrition of children and adolescents who developed Schizophrenic or other psychotic disorders later in life.
Frequent attenders in secondary care: a 3-year follow-up study of patients with medically unexplained symptoms
Authors: REID S. , CRAYFORD T. , PATEL A. , WESSELY S. , HOTOPF M.
Published: October 2003

Background. There are few longitudinal studies of patients with medically unexplained symptoms. The aim of this study was to investigate outcome in frequent attenders in secondary care who present repeatedly with medically unexplained symptoms.

Method. Forty-eight patients presenting with medically unexplained symptoms, from a sample of 61, participated in a 3-year follow-up study. Psychiatric morbidity, functional impairment and use of services were evaluated.

Results. At follow-up there was a high prevalence of psychiatric morbidity with 69% having at least one psychiatric diagnosis. The sample continued to be high users of a range of health services and substantial functional impairment was reported.

Conclusion. In this group of frequent attenders with medically unexplained symptoms outcome as measured by psychiatric morbidity, service use and functional impairment remained poor after 3 years.
Does treatment delay in first-episode psychosis really matter?
Authors: HARRIGAN S. M. , McGORRY P. D. , KRSTEV H.
Published: October 2003

Background. Relatively few predictors of outcome in first-episode psychosis are potentially malleable and duration of untreated psychosis (DUP) is one. However, the degree to which DUP is mediated by other predictors of outcome is unclear. This study examines the specific effects of DUP on 12-month outcome after adjusting for effects of potential confounders and moderating variables.

Method. The sample comprised 354 first-episode psychosis patients followed up 12-months after remission/stabilization of their psychotic symptoms. Outcome measures included functional outcome, severity of positive symptoms and negative symptoms. Hierarchical multiple regression assessed whether DUP significantly predicted 12-month outcome after adjusting for other predictors. Contrast analysis further clarified the differential effects of DUP on 12-month outcome.

Results. DUP remained a significant predictor of outcome after adjusting for the effects of other variables. This finding remained robust for the subset of patients with schizophrenia or schizophreniform disorder. Functional outcome appeared to decline substantially even after very short treatment delays (>7 days), with more gradual deterioration in functioning until very long DUP (>1 year). Good outcome was variably associated with good pre-morbid adjustment, female gender, diagnosis of affective disorder, short duration of prodromal symptoms, and treatment within the Early Psychosis Prevention and Intervention model in contrast to other models of care.

Conclusions. DUP consistently predicts outcome independently of other variables, and is not simply a proxy for other factors. As one of the few potentially malleable factors influencing outcome, DUP could prove to be a target for secondary preventive efforts in early psychosis.
Pattern of cognitive dysfunction in depressive patients during maintenance electroconvulsive therapy
Authors: RAMI-GONZÁLEZ L. , SALAMERO M. , BOGET T. , CATALAN R. , FERRER J. , BERNARDO M.
Published: October 2003

Background. Objective data regarding adverse cognitive deficits associated with maintenance electroconvulsive therapy (M-ECT) are lacking. This study examined the cognitive state of depressive patients during M-ECT.

Method. A cross-sectional study was carried out in 11 depressive patients in remission, all with a DSM-IV diagnosis of major depressive disorder. The mean number of previous ECT sessions was 36·1, and the mean intersession interval was 52·7 days. A group of 11 patients who had not received ECT was selected for comparison and matched for diagnosis, sex, age and years of schooling. All subjects were assessed using a complete neuropsychological battery including memory, attention and frontal function tests.

Results. Groups did not present differences in long delay verbal recall. Encoding of new information and results on the frontal function tests were significantly lower in the M-ECT patients.

Conclusion. Depressed patients preserve long-term memory, but suffer short-term memory impairment and frontal function alteration during M-ECT. Further longitudinal studies are necessary to determine the influence of M-ECT on non-memory functions and different memory subtypes.