Chemical changes in fed and starved larval trout cod, Maccullochella macquarensis during early development

The changes in proximate composition, amino acid (total and free) and fatty acid content of artificially propagated trout cod, Maccullochella macquariensis larvae from five mothers hatched, weaned and reared separately, each in two groups, one fed with Artemia naupli and the other starved, for 15 days (after yolk resorption), are presented. There was no significant change in the proximate composition of fed larvae with devlopment, but in starved larvae the protein (linearly) and lipid (curvi-linearly) content decreased significantly as starvation progressed. The essential amino acids (EAA) and non- essential amino acids (NEAA) found in highest amounts in trout cod larvae were lysine, leucine, threonine and arginine, and alanine, serine and glutamic acid, respectively. In fed larvae the total amino acid (TAA), TEAA and TNEAA content did not vary significantly as development progressed. In starved larvae the TAA, EAA and NEAA content, as well as all the individual amino acids decreased significantly (P<0.05) from the levels in day of hatch and/or yolk-sac resorbed larvae. The greatest decrease occurred in the TEAA content (7.38±0.76 at day of hatch to 1.96±0.09 15 day starved in μmoles larva^–1; approximately a 74% decrease), whereas the decrease in TNEAA was about 38%. Unlike in the case of TAA distinct changes in the free amino acid (FAA) pool were discernible, from day of hatch and onwards, in both fed and starved trout cod larvae. In both groups of larvae the most noticeable being the decrease of % FEAA in TFAA, but not the % FAA in TAA. Four fatty acids together, accounted for more than 50% of the total in each of the major fatty acid categories in all larvae sampled; 16: 0, 18:1n-9, 22: 6n-3 and 20: 4n-6, amongst saturates, monoenes, n-3 PUFA and n-6 PUFA, respectively. Twelve fatty acids either decreased (14: 0, 16: 1n-7, 20: 1n-9, 20: 4n-6, 20: 5n-3, 22: 5n-3 and 22: 6n-3) or increased (18: 2n-6, 18: 3n-3, 18: 3n-6, 18: 4n-3 and 20: 3n-3) in quantity, after 15 days of feeding, from the base level in day of hatch and/ or yolk- sac resorbed larvae. The greatest increase occurred in 18: 3n-3 from 6.4±0.1 to 106.2±13.1 μg mg lipid^–1 larva^–1, and the greatest decrease occurred in 22: 6n-3 (181.2±12.4 to 81.4±6.2 μg mg lipid^–1 larva^–1). In starved larvae, at the end of 15 days, all the fatty acids, except 18: 0, 20: 3n-3 and 20: 4n-6, decreased significantly (P<0.05) from the levels in day of hatch and/or yolk- sac resorbed larvae.

Population monitoring of language and cognitive development in Australia : the Australian early development index

The Australian Early Development Index (AEDI) is a population measure of child development. The AEDI measures Language and Cognitive Development, Social Competence, Emotional Maturity, Physical Health and Wellbeing, and Communication Skills and General Knowledge. In Australia these data are collected by teachers for children in their first full time year of schooling. The aim of this paper is to aid people's understanding and interpretation of population measures such as the AEDI. With a greater awareness of the merits and complexities of population data clinicians and allied health professionals can play a vital role in aiding communities and policy makers to interpret and act upon the data in an intelligent way. This paper is primarily descriptive providing background information on the development and use of the instrument utilizing one of the 5 developmental domains (Language and Cognitive Development) as an example. The results show a complex relationship between children residing in differing socio-economic regions, children with English as their primary or secondary language and children who are able or not able to effectively communicate in English.

Sodium appetite in adult rats following ω-3 polyunsaturated fatty acid deficiency in early development

We examined the effect of ω-3 polyunsaturated fatty acid (PUFA) deficiency during development on sodium appetite. Being raised on an ω-3 PUFA deficient diet increased the intake of 0.5 M NaCl following furosemide-induced sodium depletion by 40%. This occurred regardless of the diet they were maintained on later in life, and the increased consumption persisted for 3 days. In a second study, animals were administered furosemide and low-dose captopril. Sodium consumption of deficient raised animals was again higher than that of the control raised. Fos immunoreactivity in brain areas associated with sodium appetite and excretion were not influenced by diet. Our findings indicate that inadequate dietary ω-3 PUFA during development results in an exaggerated sodium appetite later in life.

Exploration of the Australian Early Development Index for children with language backgrounds other than English

The Australian Early Development Index (AEDI) is a teacher-administered measure that indicates if children are starting school with the developmental capacity to take advantage of the school learning environment. A key question that arises for schools, communities, and policy makers is how valid the AEDI is for children from a Language Background Other Than English (LBOTE). This study investigated how adequately the AEDI captures the cultural variety of different behaviours and different ways of learning. The study also examined the cultural inclusivity and relevance of the AEDI materials (e.g., teacher training guidelines; administration manual). Ten focus groups (n=84) and various community consultations were conducted with early childhood education and development professionals, representing key service providers, and school personnel. The findings from these studies led to the following recommendations: For LBOTE children, the AEDI should ideally be completed in collaboration, for example, between the child’s teacher and a multicultural consultant. The teacher guidelines for the AEDI need to be enhanced with respect to issues pertaining to LBOTE children, and the AEDI should include additional domains, such as cultural competence and home based/first language skills. Finally, teacher preparation and the AEDI administration guidelines need to clarify and emphasize the intent of the AEDI.

Pretend play and maternal scaffolding : comparisons of toddlers with advanced development, typical development, and hearing impairment

This study used measures of pretend play and maternal scaffolding to explore and compare the early development of deaf children, typically developing children, and children showing advanced intellectual development. Marked differences were found among the groups in both play development and characteristics of mother-child interactions. In particular, children who scored above 130 IQ at four years of age were found, as toddlers, to have demonstrated significantly advanced pretend play. In addition, the mothers of the high IQ children engaged in scaffolding behaviors involving higher stages of pretend transformations, verbal analogies and world links. The findings are discussed in relation to children's learning in Vygotsky's Zone of Proximal Development, as well as possible implications for future research on early gifted development.

Mother and toddler activity in the zone of proximal development for pretend play as a predictor of higher child IQ

This study investigated the pretend play of mother—toddler dyads in relation to later child IQ. Twenty-one toddlers were videotaped in monthly play sessions with their mothers, from age 8 to 17 months, and later assessed at 5 years of age on the Stanford-Binet IV. Children's and mothers' pretend play levels and frequencies were measured using Brown's (1997) Pretend Play Observation Scale. Dyadic play activity was analyzed using the conceptual frameworks of scaffolding and Vygotsky's Zone of Proximal Development (ZPD). Toddlers later assessed as having higher IQ demonstrated more rapid learning in the ZPD for pretend play and experienced earlier maternal transfer of responsibility for play. These findings support other evidence on the differential early development of high ability or gifted children and the role of caregiver interactions in that development.

Putting the Research to Use: This study provides evidence that gifted children show differential development, in this case more rapid learning, from the first year of life. It also demonstrates how responsive parental interactions can support this advanced development. For family and professional caregivers, the findings imply that optimum caregiving for the young gifted child involves interactions that are both responsive to individual potential and appropriately challenging. In regard to the methodological challenges of researching early giftedness, the study demonstrated that the constructs of the ZPD and scaffolding were useful frameworks for investigating early gifted development and caregiver influences on that development. Pretend play activity was also shown to be an effective measure and a useful context for the study of gifted development in infants and toddlers. It would be valuable for future researchers in this area to utilize similar approaches that are grounded in the unique developmental characteristics of young children, and that aim to account for the interactive contexts that are so important in children's lives. The field of gifted education, in general, would also benefit from an increased awareness and exploration of the role of play in the development of intellect, imagination and creativity.

The constructional geometry of early Javanese temples

The early development of Hindu Javanese architecture can be traced through interpretation of epigraphs, archaeological excavations, and comparison of extant temples with other traditions. However, while many scholars have speculated on connections between Javanese Hindu temples and presumed antecedents in India, these have been made on the basis of visual comparison and epigraphic interpretations. No Indian temple has been conclusively shown to be a model for the earliest Javanese temples. Archaeologist and temple historian Michael Meister has shown in his analysis of the geometric composition of early Hindu temples in South Asia how a ritual sixty-four square mandala was the geometric basis of temple construction during the formative period (fifth to eighth century) of the Indian architectural tradition. Working from an understanding of temple construction sequence as well as their ritual underpinnings, Meister found that the sixtyfour square mandala's dimensions correlate closely to the constructed dimensions at the level of the vedibandha (which corresponds with the plan level of the sanctuary threshold). Furthermore, he shows how the horizontal profile of the cella depends on the number of offsets and the proportional relationships between ech offset based on the subdivision of the sixty-four square grid. The authors have investigated whether a similar compositional basis can be found for the earliest Javanese temples on the Dieng Plateau in the highlands of central Java, despite differences in architectonic and symbolic expression. The analysis of relationships between ritual geometry and actual temple layouts for these buildings has the potential to furthering our understanding of the connections between Hindu temples in Java and those in India.

No outbreeding depression at a regional scale for a habitat-forming intertidal alga with limited dispersal

Hormosira banksii is distributed throughout southern Australasia, but dispersal of propagules is thought to be limited. In the present study, the hypothesis that outbreeding depression occurs in H. banksii was tested by assessing fertilisation success and early development of embryos in crosses between populations at local to regional spatial scales. Hierarchical experiments were conducted at three spatial scales with nesting present within each scale: small scale (within a rocky shore population), intermediate scale (regions separated by 70 km) and large scale (450-km separation between two states: Victoria and Tasmania). In each experiment, eggs and sperm were crossed within and between each population located in the spatial scale of interest. There were no consistent patterns of variable fertilisation success and subsequent development within a population or at different spatial scales. It was concluded that outbreeding depression is not detected in analyses of fertilisation success or early development processes in H. banksii. The results suggest one of the following to be likely: (1) H. banksii is capable of longer distance dispersal than previously considered, thus maintaining gene flow between distant populations, (2) gene flow is restricted by limited dispersal, but populations have not been isolated for a sufficient length of time to cause genetic divergence or (3) outbreeding depression is manifested as effects on later life-history stages.

Adoption of the world wide web by traditional Australian media organisations

The aim of this paper is it to identify whether Australian media companies moved online with a clear business model in mind or in an ad-hoc manner. In-depth interviews were conducted with four Internet media managers from two large Australian media organisations. All four had been involved in Web publishing from its early stages and had extensive knowledge of the development of Web publishing in the industry. The interviews focused on the period around the mid 1990’s when the early development of the organisations’ websites took place. We also review an analytical approach of examining narratives from research interviews developed by Davidson (Davidson 1997) and Mishler (Mishler1986a, 1986b).

Traditional Australian media organisations adoption of the World Wide Web

The aim of this paper is it to identify whether Australian media companies moved online with a clear business model in mind or in an ad-hoc manner. In-depth interviews were conducted with four Interact media managers from two large Australian media organisations. All four had been involved in Web publishing from its early stages and had extensive knowledge of the development of Web publishing in the industry. The interviews focused on the period around the mid 1990's when the early development of the organisations' websites took place. We also review an analytical approach of examining narratives from research interviews developed by Davidson (Davidson 1997) and Mishler (Mishler1986a, 1986b).

Song as an honest signal of past developmental stress in the European starling (Sturnus vulgaris)

Bird song is a sexually selected male trait where females select males on the basis of song quality. It has recently been suggested that the quality of the adult male song may be determined by nutritional stress during early development. Here, we test the 'nutritional–stress hypothesis' using the complex song of the European starling. Fledgling starlings were kept under experimental treatment (unpredictable short–term food deprivations) or control conditions (ad libitum food supply), for three months immediately after independence. We measured their physiological and immune responses during the treatment and recorded song production during the following spring. Birds in the experimental group showed increased mass during the treatment and also a significantly suppressed humoral response compared with birds in the control group. There was no difference between the groups in the cell–mediated response. Next spring, males in the experimental group spent less time singing, sang fewer song bouts, took longer to start singing and also sang significantly shorter song bouts. These data support the hypothesis that both the quality and quantity of song produced by individual birds reflect past developmental stress. The results also suggest the 'nutritional–stress hypothesis' is best considered as a more general 'developmental–stress hypothesis'.

Ontogeny of putative GABAergic neurons and their receptors in the nervous system of the crayfish Cherax destructor

Inhibitory neurons exert control the expression of many aspects of behaviour by regulating the effectiveness of excitatory neural function. By comparison with excitatory neural systems, relatively little is known about the development of inhibitory neurons and the influence which these neurons exert on the development of other neural systems. Two issues which relate to the development of inhibitory neurons are of particular interest. First, a paradox arises when inhibitory neurons are considered in terms of modern models of synaptic development which involve activity-dependent mechanisms of synaptic plasticity. Second, there is some evidence that inhibitory neurotransmitters may act in a special trophic manner during the early development of nervous systems. Investigations of these issues would be greatly facilitated in a neural system in which it was possible to experimentally control aspects of the development of individual pre- and postsynaptic cells. The aim of the results presented in this thesis was to characterise the normal development of one such system: the GABAergic inhibitory system of the Australian freshwater crayfish, Cherax destructor. The ontogeny of the inhibitory neurotransmitter GABA across the embryonic period of 30% to 100% development was investigated using immunohistochemical techniques. GABA-like immunoreactive cells and fibres were first detected in the embryonic brain region. The expression of GABA-like immunoreactivity progressed along a rostro-caudal gradient, with GABA-like immunoreactive cells being detected in the most anterior thoracic ganglia at 45% development and in all ganglia by 65% development. GABA-like immunoreactive fibres were evident in peripheral nerves as early as 55% development and ramified extensively throughout the neuropil of the nervous system by 65% development. By contrast, immunoreactivity to the primary excitatory neurotransmitter, glutamate, was not detected until 60-65% development. Glutamate-like immunoreactivity at 60-65% development was evident only in the form of punctate staining in the midline of the ventral nerve cord. Cell body staining was observed only at 90% development and was restricted to only a few cells on the periphery of the ventral nerve cord. Radio-labelled ligand binding methods and autoradiography were used to study the expression of putative GABA receptors in the Cherax embryos from 30% to 100% development. Specific binding was evident in the earliest embryos studies at 30% development. There was an initial increase in binding from 30% to 40% development, followed by a dramatic drop to almost zero binding at 50-55% development. This was followed by a gradual increase in binding levels with age, reaching a plateau at 85% development. Preliminary pharmacological evaluation of binding indicated that at least three GABA receptor types were expressed during embryonic development. Methods for culturing, dissociated neural tissues explanted form Cherax embryos at 85% development were established. The success of cultures was demonstrated by neurite extension, and neuronal networks in which neurons appeared to form connections with other neurons and with explanted muscle cells after two days in culture. Immunohistochemical studies demonstrated that some explanted neurons expressed GABA-like immunoreactivity within two days of explanting. These studies have provided a comprehensive description of the development of GABAergic neurons and their receptors in Cherax destructor embryos. The very early expression of GABA-like immunoreactivity, coupled with the early onset of specific GABA binding, strongly indicates that the GABAergic neurons are functional and able to exert an effect on other cells during much of the period of nervous system development in crayfish embryos. These results support the hypothesis that inhibitory neurons may play an important role as regulators of the overall process of assembly and maturation of the nervous system and provide a substantial basis for future experimental studies in which the specific action of inhibitory neurons on the development of discrete components of the crayfish nervous system may be investigated.

Developmental stress and female mate choice behaviour in the zebra finch

The potential effects of early environmental conditions on adult female mate choice have been largely neglected in studies of sexual selection. Our study tested whether developmental stress affects the mate choice behaviour of female zebra finches, Taeniopygia guttata, when choosing between potential mates. In an experiment manipulating developmental condition, female zebra finches were raised under nutritional stress or control conditions. In adulthood, female preferences were assessed using extensive four-stimulus mate choice trials. Nutritional stress affected growth rates during the period of stress, with experimentally stressed females lighter than controls. During mate choice trials stressed females were almost three times less active than controls and made fewer sampling visits to the stimulus males, although we found no evidence of a direct effect of developmental experience on which males were preferred. Thus, developmental experience had a clear effect on behavioural patterns in a mate choice context. To test whether this effect is specific to a mate choice context, we also investigated the effect of developmental stress on female activity rates in three social contexts: isolation, contact with a conspecific male (a potential mate) and contact with a conspecific female. Here, female activity did not differ between the experimental treatments in any of the social situations. Overall, our findings suggest that environmental conditions during early development can have long-term context-dependent consequences for adult female mate choice behaviour, mediated by changes in activity rates.

The developmental stress hypothesis: A special case of the evolution of condition-dependent sexual traits

The idea that sexually selected traits might be condition dependent is far from novel (Zahavi 1975); however, the developmental stress hypothesis was proposed as a special case because of a highly plausible mechanism: the development of the neural circuits controlling song output coincides with a period of time during which developing birds are likely to be susceptible to stress. The elegant aspect of the hypothesis is that the mechanism is defined and effects can be readily tested (Nowicki et al. 1998; Buchanan et al. 2003). Compared with more general hypotheses about the evolution of condition-dependent sexual traits (Buchanan 2000), the second particularly interesting aspect of the developmental stress hypothesis is that, in some species, individuals may suffer historical markers of stress. This is because in species with a fixed period for neural growth and song learning, there is no possibility for compensation in later life for stress experienced during early development. Females using such a marker of stress may benefit by obtaining a partner whose other cognitive functions have not been impaired by stress.

Broadband technologies, techno-optimism and the "hopeful" citizen

Using the internet to promote or facilitate learning has a relatively long history. As early as the mid-1980s, at a time when the internet itself was relatively experimental, a few early pioneers such as Hiltz were exploring the possibilities that networked computer communications technology could provide for education. Not only were universities the birthplace of the internet as a research network, they also had both staff with interests in using technology for learning as well as the critical infrastructure which might permit early development and adoption. But, with the widespread public uptake of the internet from 1994 onwards, online learning has become much more widespread-through traditional institutions of learning (schools, colleges, and universities), and also through the auto-didactic qualities of both the internet itself and many who use it; and finally through the opportunities which commercial “providers” of education and training imagine might be embedded in this new technology to deinstitutionalize learning.