Geographic information retrieval in a mobile environment: evaluating the needs of mobile individuals

This paper describes research that aims to define the information needs of mobile individuals, to implement a mobile information system that can satisfy those needs, and finally to evaluate the performance of that system with end-users. First a review of the emerging discipline of geographic information retrieval (GIR) is presented as background to the more specific issue of mobile information retrieval. Following this, a user needs study is described evaluating the requirements of potential users of a mobile information system; the study finds that there is a strong geographic component to users' information needs. Next, four geographic post-query filters are described which attempt to represent the region of space associated with an individual's query made at some specific spatial location. These filters are spatial proximity (distance in space), temporal proximity (travel time), speed-heading prediction surfaces (likelihood of visiting locations) and visibility (locations that can be seen). Two of these filters — spatial proximity and speed-heading prediction surfaces — are implemented in a mobile information system and subsequently evaluated with users in an outdoor setting. The results of evaluation suggest that retrieved information to which post-query geographic filters have been applied is considered more relevant than unfiltered information, and that users find information sorted by spatial proximity to be more relevant than that sorted by a prediction surface of likely future locations. The paper closes with a discussion of the wider implications of these results for developers of mobile information systems and location-based services

Vergence responses to vertical binocular disparity during lexical identification

Humans typically make use of both eyes during reading, which necessitates precise binocular coordination in order to achieve a unified perceptual representation of written text. A number of studies have explored the magnitude and effects of naturally occurring and induced horizontal fixation disparity during reading and non-reading tasks. However, the literature concerning the processing of disparities in different dimensions, particularly in the context of reading, is considerably limited. We therefore investigated vertical vergence in response to stereoscopically presented linguistic stimuli with varying levels of vertical offset. A lexical decision task was used to explore the ability of participants to fuse binocular image disparity in the vertical direction during word identification. Additionally, a lexical frequency manipulation explored the potential interplay between visual fusion processes and linguistic processes. Results indicated that no significant motor fusional responses were made in the vertical dimension (all p-values > .11), though that did not hinder successful lexical identification. In contrast, horizontal vergence movements were consistently observed on all fixations in the absence of a horizontal disparity manipulation. These findings add to the growing understanding of binocularity and its role in written language processing, and fit neatly with previous literature regarding binocular coordination in non-reading tasks

Gaia Early Data Release 3: The celestial reference frame (Gaia-CRF3)

Context. Gaia-CRF3 is the celestial reference frame for positions and proper motions in the third release of data from the Gaia mission, Gaia DR3 (and for the early third release, Gaia EDR3, which contains identical astrometric results). The reference frame is defined by the positions and proper motions at epoch 2016.0 for a specific set of extragalactic sources in the (E)DR3 catalogue. Aims. We describe the construction of Gaia-CRF3 and its properties in terms of the distributions in magnitude, colour, and astrometric quality. Methods. Compact extragalactic sources in Gaia DR3 were identified by positional cross-matching with 17 external catalogues of quasi-stellar objects (QSO) and active galactic nuclei (AGN), followed by astrometric filtering designed to remove stellar contaminants. Selecting a clean sample was favoured over including a higher number of extragalactic sources. For the final sample, the random and systematic errors in the proper motions are analysed, as well as the radio-optical offsets in position for sources in the third realisation of the International Celestial Reference Frame (ICRF3). Results. Gaia-CRF3 comprises about 1.6 million QSO-like sources, of which 1.2 million have five-parameter astrometric solutions in Gaia DR3 and 0.4 million have six-parameter solutions. The sources span the magnitude range G = 13-21 with a peak density at 20.6 mag, at which the typical positional uncertainty is about 1 mas. The proper motions show systematic errors on the level of 12 μas yr-1 on angular scales greater than 15 deg. For the 3142 optical counterparts of ICRF3 sources in the S/X frequency bands, the median offset from the radio positions is about 0.5 mas, but it exceeds 4 mas in either coordinate for 127 sources. We outline the future of Gaia-CRF in the next Gaia data releases. Appendices give further details on the external catalogues used, how to extract information about the Gaia-CRF3 sources, potential (Galactic) confusion sources, and the estimation of the spin and orientation of an astrometric solution

The pathology and pathogenicity of a novel Haemoproteus spp. infection in wild Little Penguins (Eudyptula minor)

One hundred and thirty four Little Penguin (Eudyptula minor) carcases found since 2004 in south west Australia were necropsied. The livers and spleens from ten of the penguins exhibited varying degrees of multifocal, randomly scattered areas of necrosis and varying numbers of parasites were associated with these areas. Hepatomegaly and splenomegaly were noted in many of these ten cases. Necrosis and parasites were also observed in the cardiac muscle of four of the cases and in the lung tissue in one of the penguins. Using PCR, the parasites were positively identified in four of the cases as Haemoproteus spp. and morphologically identical tissue stage parasites associated with histopathological changes were observed in all ten dead penguins. This is the first study to demonstrate both the in situ presence of the Haemoproteus parasite in any member of the Sphensicidae family and mortality due to its presence. We postulate the involvement of anomalous environmental conditions in a potential increase in local vectors

New species of Moaciria Freitas 1956 (Nematoda: Heterakoidea) from Australian Reptiles

Moaciria sphenomorphi n. sp. is described from the skink Sphenomorphus gracilipes, Moaciria butleri n.sp.from theelapid snake Pseudechis australis (both from Western Australia), and Moaciria etnae n. sp. from the python Liasis childreni from Queensland. These species differ from one another and from M. alvarengai and M. icosiensis principally in the number and disposition of body and caudal papillae, and from M.freitasi in possessing caudal alae. M. butleri and M. etnae also differ from the other species in possessing a conspicuous three-pointed internal lip tooth, and all three new species possess a small median papilla within the posterior rim of the precloacal sucker

Abbreviata (nematoda: Physalopteroidea) from Western Australian snakes

Four new species of Abbreviata (Physalopteridae) are reported from Western Australian snakes, viz. Abbreviata barrowi, sp. nov., Abbreviata occidentalis, sp. nov., Abbreviata kumarinae, sp. nov., and Abbreviata aechmespiculum, sp, nov. Larval Abbreviata not identifiable to species were found in almost half the snakes examined. These were almost absent from the south-west part of Western Australia and were most prevalent in the north of the state. Infections could not be related to season, or to food residues in the hosts. It is suggested that these larvae were unable to mature in the snakes, which were acting as paratenic hosts, and that the most likely definitive hosts were Varanus lizards. A key to the Abbreviata species from Australian and Papua New Guinea reptiles is provided

Dioctowittus spp. chabaud and le van hoa 1960 (nematoda: Adenophorea) from australian snakes

Dioctowittus denisoniae n. sp. from Denisonia punctata differs from D. wittei and D. chabaudi in the smaller size, lack of vestigeal male precloacal sucker, short egg-filaments, the presence of lateral expansions at the posterior end in the male, and in the expansions of the oesophageal tissue between the stichocytes. Dioctowittus sp. from Liasis amethystinus differs from the three described species in the possession of lateral lobes at both extremities

The life cycle of the reptile-inhabiting nematode Abbreviata hastaspicula (Spirurida: Physalopteridae: Physalopterinae) in Australia

This study elucidates the life-cycle of the reptile inhabiting nematode Abbreviata hastaspicula (Spirurida: Physalopteridae: Physalopterinae) in Australia. Eight Varanus gouldii (Lacertilia: Varanidae), and two Christinus marmoratus (Reptilia: Gekkonidae) lizards were captured in the wild. Two V. gouldii were used as controls and no experimental procedures were carried out on them. Another six V. gouldii (final host) and the two C. marmoratus (paratenic host) were treated with oral anthelmintics to remove all parasitic worms and were fed with infected live arthropods containing third stage larvae of Abbreviata hastaspicula. Faeces of V. gouldii were examined under the microscope weekly to determine whether the third stage larvae had developed into adults. Two months later, a total of 30 larvae and adults of A. hastaspicula were found in the stomachs of four experimentally-infected V. gouldii lizards. No cysts or larva were found in the C. marmoratus. This is the first study to demonstrate the life-cycle of this genus of nematode in their definitive reptile hosts