bluuebunny/crossref_metadata_2025_split huggingface dataset:
Emission Line Properties of GPS/CSS Galaxies
Authors: Koekemoer Anton M. , O'Dea Christopher P. , Baum Stefi A. 
Published: August 2003

AbstractWe present initial results from a program that we have begun, aimed at increasing the number of GPS and CSS sources for which good spectroscopic data are available for a variety of emission lines. We combine new observational data with previously published results to investigate whether there are any relationships between the excitation state of the gas and the radio properties of the sources, retaining distinctions between GPS and GSS galaxies and quasars. In scenarios where the youngest, most compact sources interact most strongly with the gas, it is perhaps to be expected that this can have an effect on the overall excitation state of the gas, which could therefore correlate with radio properties such as turnover frequency that plausibly trace the source size and age. However, we find a degree of scatter between the turnover frequency and gas excitation state that is several times larger than the characteristic degree of uncertainty in our line ratio measurements. This would suggest that either there is no underlying relationship between turnover frequency and excitation state, or alternatively that any potential relationship is completely diluted by variations in the intrinsic properties of the gas from one source to the next, which would thus be an important factor in determining the source properties.
Variability in GPS Sources
Authors: Jauncey D. L. , King Edward A. , Bignall Hayley E. , Lovell J. E. J. , Kedziora-Chudczer Lucyna , Tzioumis A. K. , Tingay S. J. , Macquart Jean-Pierre , McCulloch P. M. 
Published: August 2003

AbstractFlux density monitoring data at 2.3 and 8.4 GHz is presented for a sample of 33 southern hemisphere GPS sources, drawn from the 2.7 GHz Parkes survey. This monitoring data, together with VLBI monitoring data, shows that a small fraction of these sources, ∼10%, vary. Their variability falls into several categories: sources whose spectral classification is, at best, ephemeral on a timescale of years; sources with a stable GPS classification that vary, but retain their classification; and a small number of sources that exhibit interstellar scintillation, but that maintain a mean GPS spectrum. Existing data on GPS sources with higher frequency peaks, ≥3 GHz, reveals that many such sources vary. However, the majority of these sources possess a GPS spectrum only during outbursts, and hence should perhaps be classified as ephemeral GPS sources. In addition, significant levels of circular polarisation have been found in a number of GPS sources, both amongst the variables and non-variables. Remarkable amongst these is PKS 1519–273, which possesses strong and variable circular polarisation, and which exhibits IDV in all Stokes parameters.
Solar-like Oscillations
Authors: Bedding Timothy R. , Kjeldsen Hans 
Published: August 2003

AbstractThe five-minute oscillations in the Sun have provided a wealth of information about the solar interior. After many attempts, positive detections of similar oscillations in solar-type stars have now been made. This review discusses the properties of solar-like oscillations, the methods used to observe them, and the results on individual stars. We conclude that the study of solar-like oscillations from the ground and space has an exciting future.
Free–Free Absorption and the Unified Scheme
Authors: Kameno Seiji , Inoue Makoto , Wajima Kiyoaki , Sawada-Satoh Satoko , Shen Zhi-Qiang 
Published: August 2003

AbstractWe report very long baseline array (VLBA) observations at 2.3, 8.4, and 15.4 GHz towards nine gigahertz peaked spectrum (GPS) sources. One Seyfert 1 galaxy, one Seyfert 2 galaxy, three radio galaxies, and four quasars were included in our survey. We obtained spatial distributions of the free–free absorption (FFA) opacity with milliarcsecond resolution for all sources. It is found that type 1 (Seyfert 1 and quasars) and type 2 (Seyfert 2 and radio galaxies) sources showed different distributions of the FFA opacities. The type 1 sources tend to show more asymmetric opacity distributions towards a double lobe, while those of the type 2 sources are rather symmetric. Our results imply that the different viewing angle of the jet causes the difference of FFA opacity along the external absorber. This idea supports the unified scheme between quasars and radio galaxies, proposed by Barthel (1989).
Beppo SAX X-Ray Observations of PKS 1934–63 and S5 1946+708
Authors: Woltjer L. , Risaliti G. , Salvati M. 
Published: August 2003

AbstractX-ray observations of PKS 1934–63 and S5 1946+708 have been made with Beppo SAX lasting 100 and 40 ksec, respectively. Both sources were detected, and in both there is evidence (at 90% confidence) of a strong iron Kα line which would indicate that the nuclei are surrounded by Compton thick material (˜1 g cm−2).For 1946+708 VLBI H I absorption data are available from the literature. With the condition that free–free absorption should be modest for the source to be observable a minimum radius of around 20 pc is derived for the absorbing torus. The torus is predominantly molecular with a density of 108 cm−3. The corresponding pressure is rather high. Observations with XMM have been requested to verify the large equivalent width of Kα with a better confidence level.In 1934–63 no important H I absorption was previously detected and no nucleus has been seen in radio data at 8 GHz. If this is due to free–free absorption a molecular torus with a radius less than 5 pc could be responsible. The density would be 108 cm−3 or more.The relatively low S/N ratio of our observations does not allow a fully convincing conclusion to be reached. But our discussion shows that the combination of X-ray and high resolution 21-cm absorption data can provide important information on the physical parameters in the absorbing ‘torus’.Paper to appear in full in Astronomy and Astrophysics.
A review of the genus Eriogenes Meyrick (Lepidoptera : Elachistidae : Stenomatinae) in Australia
Authors: Edwards E. D. 
Published: August 2003

The genus Eriogenes Meyrick, with three species, is reviewed. A lectotype of Phanaca cossoides Butler is designated and the species placed in Eriogenes as a senior subjective synonym of E. meyricki Duckworth. The known species of Eriogenes Meyrick, E. mesogypsa Meyrick and E. cossoides both described from Papua New Guinea, are redescribed based on Australian material and E. mesogypsa is recorded from Australia for the first time. A third, and new, species from Australia is described here as E. nielseni, sp. nov. Females of Eriogenes were previously unknown but females of two species are described here. Characters to differentiate Eriogenes and Agriophara Rosenstock are discussed.
Genetic, cytogenetic and morphological patterns in a mixed mulga population: evidence for apomixis
Authors: Andrew Rose L. , Miller Joseph T. , Peakall Rod , Crisp Michael D. , Bayer Randall J. 
Published: August 2003

The mulga complex (Acacia aneura and closely related taxa) is a widespread group that is dominant in much of arid Australia. The group is taxonomically difficult, due to a complex interaction of sympatry and putative hybridisation between the major species, geographic variation within species and sympatric variation within A. aneura. Mulga is highly variable in a wide range of vegetative and reproductive characters and it is not unusual to find five or six distinct forms growing side by side. The aim of this project was to gain a better understanding of the relationships among mulga species and A. aneura varieties, as well as the maintenance of this variation. A single site in the Northern Territory, containing A. ayersiana, A. minyura and two varieties of A. aneura, was sampled intensively. Six morphotypes were observed in the field and five were strongly supported by morphometric analysis. Although the mulga complex is generally tetraploid (2n = 52), triploid (2n = 39) and pentaploid (2n = 65) seedlings were produced in the study population. Microsatellite primers developed for A. mangium (sect. Juliflorae) were amplified in individuals of each morphotype, resulting in genetic marker patterns consistent with polyploidy. Genetic and morphometric distances were correlated and differences between morphotypes account for 63% of the total genetic variation (ΦPT = 0.63, P < 0.001). Allele sequences confirmed the presence of genuine heterozygosity and clonality was suggested by the low genotypic diversity and the lack of allele segregation. Seedlings had identical genotypes to the maternal plants and polyembryony was observed in each taxon, consistent with apomictic reproduction. Both variation of the ploidy level and apomixis may restrict gene flow among morphotypes, playing a role in the maintenance of morphological diversity at the study site. The success of the group in arid and semi-arid Australia may also be due, in part, to these factors.
Clinal variation and genetic divergence in Acacia tumida (Mimosaceae)
Authors: McDonald M. W. , Butcher P. A. , Bell J. C. , Nguyen C. V. 
Published: August 2003

Acacia tumida F.Muell ex. Benth. is a morphologically variable species from north-western Australia. Variants range from low, multi-stemmed shrubs to single-stemmed trees. Acacia tumida is cultivated for firewood, windbreaks and sand stabilisation. To examine patterns of genetic variation that could be utilised in domestication programs, 22 populations representing its natural distribution were surveyed by using allozymes. Estimates of genetic diversity (HE = 0.149) were within the range of other tropical, widespread woody plants, but varied widely among populations (HE = 0.064–0.203). There were strong clinal trends in diversity estimates; A, P, HO, HE were correlated with longitude and declined from west to east. HE decreased as mean monthly maximum temperatures increased and allelic richness (A) increased with mean minimum monthly temperatures. There were also significant correlations between allele frequencies at certain loci and geographic and climatic parameters. Significant isolation-by-distance and relatively high levels of differentiation (θ = 0.176) were detected among populations. Populations of the narrow-phylloded form (Pilbara region) were the most genetically divergent, despite their geographic proximity to other populations. The low-shrub and tall-tree forms could not be distinguished by allozyme profiles. Slight genetic differences were detected between the non-pruinose and pruinose forms from within one population. Phylogenetic analysis supported morphological evidence of hybridisation between A. tumida and A. difficilis Maiden in their zone of overlap. The results are discussed in relation to the taxonomy and domestication of A. tumida.
The life cycle of Reticulitermes spp. (Isoptera: Rhinotermitidae): what do we know?
Authors: Lainé L.V. , Wright D.J. 
Published: August 2003

AbstractThe subterranean termites in the genus Reticulitermes have a complex and plastic life cycle, which has been the subject of a number of publications over the past century. Given the inherent difficulties in studying such cryptic, eusocial organisms it is not perhaps surprising that the literature on their biology has failed to reach a consensus. An overview of the literature is given, which is followed by a discussion of the various theories on the life cycle of Reticulitermes spp. A substantial proportion of the review focuses on the French literature, which constitutes the majority of the primary sources and can be difficult to access. There are many discrepancies in the literature in terms of the number of instars, the definition of workers and the question of whether they should be termed pseudergates or, potentially, an additional terminology used to differentiate between pseudergates and the true workers seen in the higher termites (Isoptera: Termitidae). It remains very difficult to compare publications as there is little conformity; a problem that is aggravated by a general absence of drawings of the relevant instars. Further work on the biology of Reticulitermes is clearly required. There is also a need for researchers to agree on a standard terminology for this genus. A glossary is provided for the various synonyms and definitions.
Incidence of insecticide resistance alleles in sexually-reproducing populations of the peach–potato aphid Myzus persicae (Hemiptera: Aphididae) from southern France
Authors: Guillemaud T. , Brun A. , Anthony N. , Sauge M.H. , Boll R. , Delorme R. , Fournier D. , Lapchin L. , Vanlerberghe-Masutti F. 
Published: August 2003

AbstractIntensive chemical treatments have led to the development of a number of insecticide resistance mechanisms in the peach–potato aphid Myzus persicae (Sulzer). Some of these mechanisms are known to be associated with negative pleiotropic effects (resistance costs). Molecular and biochemical methods were used to determine the genotypes or phenotypes associated with four insecticide resistance mechanisms in single aphids from sexually-reproducing populations in southern France. The mechanisms considered were E4 and FE4 carboxylesterase overproduction, modified acetycholinesterase, and kdr and rdl resistance-associated mutations. A new method for determining individual kdr genotypes is presented. Almost all resistant individuals overproduced FE4 carboxylesterase, whereas modified acetylcholinesterase was rare. Both the kdr and rdl resistance mutations were present at high frequencies in French sexually-reproducing populations. The frequencies of insecticide resistance genes were compared before and after sexual reproduction in one peach orchard at Avignon to evaluate the potential impact of selection on the persistence of resistance alleles in the over-wintering phase. The frequencies of the kdr and rdl mutations varied significantly between autumn and spring sampling periods. The frequency of the kdr mutation increased, probably due to pyrethroid treatments at the end of the winter. Conversely, the frequency of the rdl mutation decreased significantly during winter, probably because of a fitness cost associated with this mutation.
The effect of chrysanthemum leaf trichome density and prey spatial distribution on predation of Tetranychus urticae (Acari: Tetranychidae) by Phytoseiulus persimilis (Acari: Phytoseiidae)
Authors: Stavrinides M.C. , Skirvin D.J. 
Published: August 2003

AbstractThe effect of plant architecture, in terms of leaf hairiness, and prey spatial arrangement, on predation rate of eggs of the spider mite, Tetranychus urticae Koch, by the predatory mite Phytoseiulus persimilis Athias-Henriot was examined on cut stems of chrysanthemums. Three levels of leaf hairiness (trichome density) were obtained using two different chrysanthemum cultivars and two ages within one of the cultivars. The number of prey consumed by P. persimilis was inversely related to trichome density. At low prey densities (less than ten eggs per stem), prey consumption did not differ in a biologically meaningful way between treatments. The effect of prey spatial arrangement on the predation rate of P. persimilis was also examined. Predation rates were higher in prey patches on leaves adjacent to the release point of P. persimilis, but significantly greater numbers of prey were consumed in higher density prey patches compared to low density patches. The predators exhibited non-random searching behaviour, spending more time on leaves closest to the release point. The implications of these findings for biological control and predator–prey dynamics are discussed.
Patterns of resistance to three cereal aphids among wheats in the genus Triticum (Poaceae)
Authors: Migui S.M. , Lamb R.J. 
Published: August 2003

AbstractForty-one accessions of wild and cultivated wheats belonging to 19 Triticum species were tested in the field for resistance to three species of aphids, Rhopalosiphum padi Linnaeus, Sitobion avenae Fabricius and Schizaphis graminum Rondani. Antibiotic resistance was estimated by the increase in biomass of aphids over 21 days on adult plants. Overall resistance was estimated by the plant biomass lost due to aphid infestation. All three species of aphids survived and reproduced on all wheats, and reduced spike biomass compared to uninfested controls. The level of antibiosis varied among wheat species and among accessions, with accessions from three, five and one species showing antibiosis to R. padi, S. avenae and S. graminum, respectively. Overall resistance to the three aphid species was observed in five to seven accessions per aphid species. Resistance was usually specific to one aphid species. The frequency of accessions with antibiosis or overall resistance was associated with the ploidy level of the plant species. Except for overall resistance to R. padi, resistance was highest for diploid species and lowest for hexaploid species. No consistent relationship between resistance and level of domestication was detected. Accessions of the wild wheats, Triticum boeoticum Bois, Triticum tauschii (Coss.) Schmal. and Triticum araraticum Jakubz. exhibited high levels of resistance to aphids, as did Triticum monococcum L. which is derived from T. boeoticum. Nevertheless, individual susceptible or resistant accessions occurred at all levels within the evolutionary tree of wheat.
Biological control of the larger grain borer Prostephanus truncatus (Coleoptera: Bostrichidae) in Kenya using a predatory beetle Teretrius nigrescens(Coleoptera: Histeridae)
Authors: Hill M.G. , Nang'ayo F.L.O. , Wright D.J. 
Published: August 2003

AbstractThe establishment of the predatory histerid beetle, Teretrius nigrescens Lewis, following its field release in south eastern Kenya in 1992, and its impact on populations of the larger grain borer, Prostephanus truncatus (Horn), in woodland habitats is evaluated. Pheromone trap catch data show a single strong peak of P. truncatus from November to January, coincident with the short rains. Comparisons of P. truncatus pheromone trap catches before and after predator establishment, and in areas with and without T. nigrescens, show a sustained decline of over 80% in P. truncatus abundance over a 5-year period, following the establishment T. nigrescens. Concurrent laboratory studies of the impact of T. nigrescens on populations of P. truncatus raised on a wood substrate showed a 77% reduction in the growth of the pest population. These results are compared with published findings of the impact of T. nigrescens as a biological control agent of P. truncatus in west Africa.
Response of female Cydia molesta (Lepidoptera: Tortricidae) to plant derived volatiles
Authors: Natale D. , Mattiacci L. , Hern A. , Pasqualini E. , Dorn S. 
Published: August 2003

AbstractPeach shoot volatiles were attractive to mated female oriental fruit moth, Cydia molesta (Busck), in a dual choice arena. No preference was observed between leaf odours from the principle host plant, peach, and the secondary host plant, apple. Twenty-two compounds were identified in headspace volatiles of peach shoots using gas chromatography–mass spectrometry. Green leaf volatiles accounted for more than 50% of the total emitted volatiles. A bioassay-assisted fractionation using different sorbent polymers indicated an attractant effect of compounds with a chain length of 6–8 carbon atoms. The major compounds of this fraction were tested either singly or in combinations for behavioural response of females. Significant bioactivity was found for a three-component mixture of (Z)-3-hexen-1-yl acetate, (Z)-3-hexen-1-ol and benzaldehyde in a 4:1:1 ratio. This synthetic mixture elicited a similar attractant effect as the full natural blend from peach shoots as well as the bioactive fraction.
Actually how Empowering is Microcredit?
Authors: Mahmud Simeen 
Published: August 2003

AbstractThis article re‐assesses the effect of microcredit programme participation on women's empowerment by applying an analytical framework that recognizes the conceptual shift in emphasis in the definition of empowerment, from notions of greater well‐being of women to notions of women's choice and active agency in the attainment of greater well‐being. The author finds that microcredit programme participation has only a limited direct effect in increasing women's access to choice‐enhancing resources, but has a much stronger effect in increasing women's ability to exercise agency in intra‐household processes. Consequently, programme participation is able to increase women's welfare and possibly to reduce male bias in welfare outcomes, particularly in poor households.
On the Spatial Dynamics of Democratic Politics: Analysing the Bolivian Case
Authors: Slater David 
Published: August 2003

AbstractAfter an initial discussion of the ‘diverse spaces of democracy’, which sets out the main points of the author's approach to democratic politics, this article considers three perspectives on the relations between governmental decentralization and territorial democracy in Latin America. These two interrelated sections provide a thematic and conceptual background to a more specific treatment of the development and dynamics of decentralization in the Bolivian case. In examining the decentralization process in Bolivia, the article highlights the two spatial modes of this process — the regional and the local — and includes an appraisal of the relation between both modes and the nature of democratic politics.
The Spatially Splintered State: Myths and Realities in the Regulation of Marine Fisheries in Tamil Nadu, India
Authors: Bavinck Maarten 
Published: August 2003

AbstractThe spatial dimension of law is a neglected field of study. This article responds to suggestions that have been made to develop a ‘geography of law’, and investigates expressions of State‐centred law regarding common pool natural resources. It asks how variations in law between lower‐level territorial units are to be explained in situations where patterns of resource exploitation are similar and the overarching State proclaims an even approach. To explore these issues, the article focuses on a case study of Tamil Nadu marine fisheries. Comparing the reality of State regulation in different coastal districts, the author argues that the State occupies a relatively weak position vis‐à‐vis user groups, and strives to maximize its legitimacy by adapting to local political circumstances. The end result is a legal patchwork with strong spatial connotations.
Struggling to Save Cash: Seasonal Migration and Vulnerability in West Bengal, India
Authors: Rogaly Ben , Rafique Abdur 
Published: August 2003

AbstractThis article concerns an important but overlooked means by which able‐bodied poor people get hold of lump sums of cash in rural West Bengal: seasonal migration for agricultural wage work. Drawing on a regional study of four migration streams, our main focus here is on the struggle to secure this cash by landless households in just one of those streams, originating in Murshidabad District. Case studies are used to illustrate the importance for women in nuclear families of maintaining supportive networks of kin for periods when men are absent. A parallel analysis is made of the negotiations between male migrant workers and their employers, at labour markets, during the period of work, and afterwards. The article then briefly discusses some of the contrasting ways in which remittances are used by landless households and owners of very small plots of land, in the context of rapid ecological change, demographic pressure and growing inequality.