Spatial distribution and developmental appearance of postjunctional P2X(1) receptors on smooth muscle cells of the mouse vas deferens

P2X(1)-type purinoceptors, have been shown to mediate fast transmission between sympathetic varicosities and smooth muscle cells in the mouse vas deferens but the spatial organization of these receptors on the smooth muscle cells remains inconclusive. Voltage clamp techniques were used to estimate the amplitudes of spontaneous excitatory junction currents (SEJCs) in cells of the vas deferens longitudinal smooth muscle layer. These currents involved the activation of about 6% of the P2X-type channels present on the cell, as compared to whole cell currents produced when isolated smooth muscle cells were exposed to maximal concentrations of either ATP or alpha,beta -MeATP. Immunofluorescence staining of the vas deferens with antibodies against P2X(1) receptor showed a diffuse, grainy distribution over the entire membrane of each smooth muscle cell. Anti-P2X(1) staining was not markedly clustered beneath anti-SV2-stained sympathetic varicosities. Similar results were obtained for cells in the urinary bladder. During development, P2X(1) mRNA was detected as early as embryonic day 15 (E15). Increasing intensities of diffuse immunostaining for P2X(1) were observed in the walls of the bladder, tail artery, and aorta from E15 until 6 weeks postnatal. The vas deferens showed increasing intensities of diffuse staining of its smooth muscle layers between 2 and 6 weeks postnatal, consistent with the time-course of development of fast purinergic transmission described previously. Together, the results suggest that the response of smooth muscle of the vas deferens to ATP released from sympathetic varicosities relies on rapidly desensitizing P2X(1) receptors, distributed diffusely across the smooth muscle cell surface. Synapse 42:1-11, 2001. (C) 2001 Wiley-Liss, Inc.

Design, development, and testing of X-band amplifying reflectarrays

The design and development of two X-band amplifying reflectarrays is presented. The arrays use dual-polarized aperture coupled patch antennas with FET transistors and phasing circuits to amplify a microwave signal and to radiate it in a chosen direction. Two cases are considered, one when a reflectarray converts a spherical wave due to a feed horn into a plane wave radiated into a boresight direction, and two, when the reflectarray converts a spherical wave due to a dual-polarized four-element feed array into a co-focal spherical wave. This amplified signal is received in an orthogonal port of the feed array so that the entire structure acts as a spatial power combiner. The two amplifying arrays are tested in the near-field zone for phase distribution over their apertures to achieve the required beam formation. Alternatively, their radiation patterns or gains are investigated.

Coordinated expression of scleraxis and Sox9 genes during embryonic development of tendons and cartilage

Embryonic development of tendons is in close association with that of cartilage and bone. Although these tissues are derived from mesenchymal progenitor cells which also give rise to muscle and fat, their fates clearly diverse in early embryonic stages, Transcription factors may play pivotal roles in the process of determination and differentiation of tendon cells as well as other cells in the skeletal system. Scleraxis, a basic helix-loop-helix (bHLH) type transcription factor. is expressed in mesenchymal progenitors that later form connective tissues including tendons. Sox9 is an HMG-box containing transcription factor, which is expressed at high levels in chondrocytes. We hypothesized that the two transcription factors regulate the fate of cells that interact with each other at the interface between the two tissues during divergence of their differentiation pathways, To address this point, we investigated scleraxis and Sox9 rnRNA expression during mouse embyogenesis focusing on the coordinated development of tendons and skeletons, In the early stage of mesenchymal tissue development at 10.5 d.p.c., scleraxis and Sox9 transcripts were expressed in the mesenchymal progenitor cells in the appendicular and axial mesenchyme. At 11.5 d.p.c.. scleraxis transcripts were observed in the mesenchymal tissue surrounding skeletal primordia which express Sox9. From this stage, scleraxis expression was closely associated with, but distinct from, formation of skeletal primordia, At 13.5 d.p.c., scleraxis was expressed broadly in the interface between muscle and skeletal primordia while Sox9 expression is confined within the early skeletal primordia. Then. at 15.5 d.p.c., scleraxis transcripts were more restricted to tendons. These observations revealed the presence of temporal and spatial association of scleraxis expression during embryonic development of tendon precursor cells in close association with that of So,0 expression in chondrogenic cells in skeletal tissues. (C) 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.

Development of axon pathways in the zebrafish central nervous system

The zebrafish has a number of distinct advantages as an experimental model in developmental biology. For example, large numbers of embryos can be generated in each lay, development proceeds rapidly through a very precise temporal staging which exhibits minimal batch-to-batch variability, embryos are transparent and imaging of wholemounts negates the need for tedious histological preparation while preserving three-dimensional spatial relationships. The zebrafish nervous system is proving a convenient model for studies of axon guidance because of its small size and highly stereotypical trajectory of axons. Moreover, a simple scaffold of axon tracts and nerves is established early and provides a template for subsequent development. The ease with which this template can be visualized as well as the ability to spatially resolve individual pioneer axons enables the role of specific cell-cell and molecular interactions to be clearly deciphered. We describe here the morphology and development of the earliest axon pathways in the embryonic zebrafish central nervous system and highlight the major questions that remain to be addressed with regard to axon guidance.

Spatial distribution of vectors of Ross River virus and Barmah Forest virus on Russell Island, Moreton Bay, Queensland

We used a network of 20 carbon dioxide- and octenol-supplemented light traps to sample adult mosquitoes throughout Russell Island in southern Moreton Bay, south-east Queensland. Between February and April 2001, an estimated 1365 564 adult female mosquitoes were collected. In contrast to an average catch of 9754 female mosquitoes per trap night on Russell Island, reference traps set on Macleay Island and on the mainland returned average catches of 3172 and 222, respectively. On Russell Island, Ochlerotatus vigilax (Skuse), Coquillettidia linealis (Skuse), Culex annulirostris Skuse and Verrallina funerea (Theobald), known or suspected vectors of Ross River (RR) and/or Barmah Forest (BF) viruses, comprised 89.6% of the 25 taxa collected. When the spatial distributions of the above species were mapped and analysed using local spatial statistics, all were found to be present in highest numbers towards the southern end of the island during most of the 7 weeks. This indicated the presence of more suitable adult harbourage sites and/or suboptimal larval control efficacy. As immature stages and the breeding habitat of Cq. linealis are as yet undescribed, this species in particular presents a considerable impediment to proposed development scenarios. The method presented here of mapping the numbers of mosquitoes throughout a local government area allows specific areas that have high vector numbers to be defined.

Temporal and spatial expression of fibroblast growth factor receptor 4 isoforms in murine tissues

Fibroblast growth factor receptors (FGFRs) undergo highly regulated spatial and temporal changes of expression during development. This study describes the use of quantitative reverse transcriptase-polymerase chain reaction and immunochemistry to assess the changes in expression of FGFR4 as compared to its FGFR4-17a and -17b isoforms in mouse tissues, from early embryogenesis through to adulthood. Compared to FGFR4, the expression of the isoforms is more restricted at all developmental stages tested. The reverse transcriptase-polymerase chain reaction demonstrated that FGFR4 is expressed in more tissue types than either of its isoforms: it was found predominantly in lung, liver, brain, skeletal muscle and kidney, whereas the FGFR4-17a form was detected in lung and skeletal muscle, and the FGFR4-17b form only in lung, liver, skeletal muscle and kidney. Immunohistochemistry confirmed strong FGFR4-17b expression in the postnatal lung. When combined, the results suggest that FGFR4 variants play important roles particularly in lung and skeletal muscle development.

Expression of anterior Hox genes during larval development of the gastropod Haliotis asinina

We report the spatial expression patterns of five anterior Hox genes during larval development of the gastropod mollusc Haliotis asinina, an unsegmented spiralian lophotrochozoan. Molecular alignments and phylogenetic analysis indicate that these genes are homologues of Drosophila HOM-C genes labial, proboscipedia, zen, Deformed, and Sex combs reduced, the abalone genes are named Has-Hox1, -Hox2, -Hox3, -Hox4, and -Hox5. Has-Hox transcripts are first detected in the free-swimming trochophore larval stage- and restricted to the posttrochal ectoderm. Has-Hox2, -Hox3, and -Hox4 are expressed in bilaterally symmetrical and overlapping patterns in presumptive neuroectodermal cells on the ventral side of the trochophore. Has-Hox1 expression is restricted to a ring of cells on the dorsoposterior surface, corresponding to the outer mantle edge where new larval shell is being synthesized. There appears to be little change in the expression domains of these Has-Hox genes in pre- and posttorsional veliger larvae, with expression maintained in ectodermal and neuroectodermal tissues. Has-Hox2, -Hox3, -Hox4, and-Hox5 appear to be expressed in a colinear manner in the ganglia and connectives in the twisted nervous system. This pattern is not evident in older larvae. Has-Hox1 and-Hox4 are expressed in the margin of the mantle in the posttorsional veliger, suggesting that Hox genes play a role in gastropod shell formation.

Electropalatographic assessment of tongue-to-palate contacts exhibited in dysarthria following traumatic brain injury: Spatial characteristics

Consonant imprecision has been reported to be a common feature of the dysarthric speech disturbances exhibited by individuals who have sustained a traumatic brain injury (TBI). Inaccurate tongue placements against the hard palate during consonant articulation may be one factor underlying the imprecision. To investigate this hypothesis, electropalatography (EPG) was used to assess the spatial characteristics of the tongue-to-palate contacts exhibited by three males (aged 23-29 years) with dysarthria following severe TBI. Five nonneurologically impaired adults served as control subjects. Twelve single-syllable words of CV or CVC construction (where initial C = /t, d, S, z, k, g/, V=/i, a/) were read aloud three times by each subject while wearing an EPG palate. Spatial characteristics were analyzed in terms of the location, pattern, and amount of tongue-to-palate contact at the frame of maximum contact during production of each consonant. The results revealed that for the majority of consonants, the patterns and locations of contacts exhibited by the TBI subjects were consistent with the contacts generated by the group of control subjects. One notable exception was one subject's production of the alveolar fricatives in which complete closure across the palate was demonstrated, rather than the characteristic groove configuration. Major discrepancies were also noted in relation to the amount of tongue-to-palate contact exhibited, with two TBI subjects consistently demonstrating increased contacts compared to the control subjects. The implications of these findings for the development of treatment programs for dysarthric speech disorders subsequent to TBI are highlighted.

Scaffolding and bilingual shared reading experiences: Promoting primary school students' learning and development

This paper explores the connections between scaffolding, second language learning and bilingual shared reading experiences. A socio- cultural theory of cognition underpins the investigation, which involved implementing a language and culture awareness program (LCAP) in a year 4 classroom and in the school community. Selected passages from observations are used to analyse the learning of three students, particularly in relation to languages other than English (LOTE). As these three case study students interacted in the classroom, at home and in the community, they co-constructed, appropriated and applied knowledge form one language to another. Through scaffolding, social spaces were constructed, where students learning and development were extended through a variety of activities that involved active participation, such as experimenting with language, asking questions and making suggestions. Extending these opportunities for student learning and development is considered in relation to creating teaching and learning environments that celebrate socio-cultural and linguistic diversity.

The design and implementation of a repository for the management of spatial data integrity constraints

This paper reviews the key features of an environment to support domain users in spatial information system (SIS) development. It presents a full design and prototype implementation of a repository system for the storage and management of metadata, focusing on a subset of spatial data integrity constraint classes. The system is designed to support spatial system development and customization by users within the domain that the system will operate.

Regional development rhrough domestic and tourist event policies: Gold Coast and Brisbane 1974-2003

Governments, as key stakeholders in the development of events, produce policies to facilitate the growth and potential of events as a platform for industry and economic development. To date, however, there has been a paucity of research undertaken to determine the appropriateness and the consequences of government policies pertaining to events. This paper studies the event policies of two Australian local government authorities, the Gold Coast City Council and Brisbane City Council, from 1974-2003, as measured by four development paradigms: Modernisation, Dependency, Economic Neoliberalism, and Alternative. The analysis revealed that these policies were predominantly underpinned by the Alternative which has a strong socio-cultural focus. Increased awareness and utilisation of the various development paradigms will assist local governments in producing future event policies to promote growth of the event industry and concomitantly, appropriate development within their region.

Origins and early development of human body knowledge

As a knowable object, the human body is highly complex. Evidence from several converging lines of research, including psychological studies, neuroimaging and clinical neuropsychology, indicates that human body knowledge is widely distributed in the adult brain, and is instantiated in at least three partially independent levels of representation. Sensori-motor body knowledge is responsible for on-line control and movement of one's own body and may also contribute to the perception of others' moving bodies; visuo-spatial body knowledge specifies detailed structural descriptions of the spatial attributes of the human body; and lexical-semantic body knowledge contains language-based knowledge about the human body. In the first chapter of this Monograph, we outline the evidence for these three hypothesized levels of human body knowledge, then review relevant literature on infants' and young children's human body knowledge in terms of the three-level framework. In Chapters II and III, we report two complimentary series of studies that specifically investigate the emergence of visuospatial body knowledge in infancy. Our technique is to compare infants' responses to typical and scrambled human bodies, in order to evaluate when and how infants acquire knowledge about the canonical spatial layout of the human body. Data from a series of visual habituation studies indicate that infants first discriminate scrambled from typical human body pictures at 15 to 18 months of age. Data from object examination studies similarly indicate that infants are sensitive to violations of three-dimensional human body stimuli starting at 15-18 months of age. The overall pattern of data supports several conclusions about the early development of human body knowledge: (a) detailed visuo-spatial knowledge about the human body is first evident in the second year of life, (b) visuo-spatial knowledge of human faces and human bodies are at least partially independent in infancy and (c) infants' initial visuo-spatial human body representations appear to be highly schematic, becoming more detailed and specific with development. In the final chapter, we explore these conclusions and discuss how levels of body knowledge may interact in early development.

A way forward for land-use planning to achieve policy goals by using spatial modelling scenarios

This paper investigates how demographic (socioeconomic) and land-use (physical and environmental) data can be integrated within a decision support framework to formulate and evaluate land-use planning scenarios. A case-study approach is undertaken with land-use planning scenarios for a rapidly growing coastal area in Australia, the Shire of Hervey Bay. The town and surrounding area require careful planning of the future urban growth between competing land uses. Three potential urban growth scenarios are put forth to address this issue. Scenario A ('continued growth') is based on existing socioeconomic trends. Scenario B ('maximising rates base') is derived using optimisation modelling of land-valuation data. Scenario C ('sustainable development') is derived using a number of social, economic, and environmental factors and assigning weightings of importance to each factor using a multiple criteria analysis approach. The land-use planning scenarios are presented through the use of maps and tables within a geographical information system, which delineate future possible land-use allocations up until 2021. The planning scenarios are evaluated by using a goal-achievement matrix approach. The matrix is constructed with a number of criteria derived from key policy objectives outlined in the regional growth management framework and town planning schemes. The authors of this paper examine the final efficiency scores calculated for each of the three planning scenarios and discuss the advantages and disadvantages of the three land-use modelling approaches used to formulate the final scenarios.

A flexible and practical framework for reporting on ecologically sustainable development for wild capture fisheries

The principles of sustainable development (or ecologically sustainable development as it is known in Australia) are now accepted as the foundation for natural resource management worldwide and there are increasing community expectations that they will be implemented explicitly. Previous attempts to assess sustainable development for fisheries have mostly failed because the methods have been too restrictive, often attempting to develop a single set of indicators. In 2000, all the fishery agencies and major stakeholder groups in Australia supported the development of a National ESD Framework. This initiative resulted in a practical system being generated through the results of a series of case studies and stakeholder workshops. The Australian National ESD Framework divides ESD into eight major components within the three main categories of ecological well-being, human well-being and ability to contribute: Four main steps are used to complete an ESD report for a fishery: (1) identify relevant issues, (2) prioritise these using risk assessment, (3) complete appropriately detailed reports on each issue and (4) compile the material into a report. The tools to assist this process are now available and have been used to generate reports for many Australian fisheries. (C) 2004 Elsevier B.V. All rights reserved.