78 resultados para Estuarine animals

em Deakin Research Online - Australia


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Childhood cruelty to animals may be a marker of poor prognosis amongst conduct disordered children. However, other than semistructured interviews with parents or children, there are no screening instruments for this behavior. The aim of this study was to develop such an instrument. In the first phase of the study, a parent-report questionnaire, Children's Attitudes and Behaviors Towards Animals (CABTA) was designed and piloted on 360 elementary school children, enabling community norms and a factor structure for the instrument to be derived. In the second phase, the questionnaire was completed by the parents of a small sample of children (N= 17) to establish its test-retest reliability. In the third phase of the study, the CABTA was completed by the parents of 19 children who had been diagnosed with either a Disruptive Behavioral Disorder or Attention Deficit Hyperactivity Disorder, and the results were compared with the outcome of a semistructured interview with parents regarding their child's behavior toward animals. The results of the various phases of the study indicated that the CABTA consists of two factors, Typical and Malicious Cruelty to animals, and is a reliable and valid tool for detecting childhood cruelty to animals. Possible use and adaptations of the CABTA as a screening instrument in clinical and community samples are discussed.

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Both prokaryotes and eukaryotes express a set of highly conserved proteins in response to external and internal stress. The stressors include tissue trauma,anoxia, heavy metal toxicity, infection, changed salinity, and the mmost characterized, heat shock. The result is an expression of stress proteins or heat shock proteins (HSP's) which lead to protection of protein integrity, and also to tolerance under continued heat stress conditions. The Australian backflip abalone (Haliotis rubra) is found principally in southern coastal water and also in estuarine/bay environments. Esturaine/bay environments have greater fluctuations in environmental conditions, especially those of salinity and water temperature, than they are found along oceanic coasts. Abalone from esturaine/bay and oceanic coastal environments were subjected to either increased temperature (2° C/day for a total of 10°C) or hyposalinity (80% seawater). Esturaine/bay abolone were less affectes than the oceanic animals by temperature increase and also demonstrated the ability to volume regualte 3 h after the initial salinity shock. SDS-PAGE and Western blotting techniques, together with dot blots of total protein, using HSP70 specific antibodies, were used to detect HSP70s in the foot muscle of the animals and indicated an expression of HSP70 in response to heat shock in abalone, but not following hyposalinity shock. RT-PCR yeilded a partial cDNA clone of HSP70 from the foot muscle.

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The densities of two common intertidal/shallow subtidal bivalves, Soletellina alba and Arthritica helmsi, were sampled in vegetated and unvegetated habitats of the Hopkins River estuary on three occasions during the  autumn/winter 1995.Winter flooding coincided with mass mortalities of the infaunal bivalve S. alba, but not A. helmsi. Mortalities were apparent for individuals living deeper in the sediment (≈35 cm) in vegetated and unvegetated habitats, but small S. alba (<1mm) were less susceptible to mortality than larger individuals (>1mm). Mortalities were similar across different habitat types and sediment depths, and at multiple sites within close proximity to the estuary mouth.

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Sewage effluent is a powerful agent of ecological change in estuaries. While the effects of sewage pollution on water quality are usually well documented, biological responses of exposed organisms are not. We quantified health impacts in the form of pathological tissue changes across multiple organs in estuarine fish exposed to elevated levels of treated wastewater. Structural pathologies were compared in wild populations of four fish species from two subtropical estuaries on the east coast of Australia that differ substantially in the amount of direct wastewater loadings. Uptake of sewage-derived  nitrogen by fish was traced with stable nitrogen isotopes. Pathologies were common in the liver, spleen, gill, kidney and muscle tissues, and included granulomas, melanomacrophage aggregates, and multiple deformities of the gill epithelia. Tissue deformities were more frequent in fish exposed directly to wastewater discharges. Mullet (Valamugil georgii) were most affected, with only a single specimen free of pathologies in the sewage-impacted estuary. Similarly, in those fish that had structural abnormalities, more deformities were generally found in individuals from sites receiving sewage. These spatial contrasts in impaired fish health correspond to significantly enriched δ15N values in fish muscle as a consequence of fish assimilating sewage-N. Overall, the pattern of lower health and enriched δ15N values in fish from sewage-impacted areas suggests that organism health is lowered by sewage inputs to estuaries. Measurements of organism health are required to understand the effects of sewage on estuarine ecosystems, and histopathology of fishes is a powerful tool to achieve this.

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n reptiles, accumulating evidence suggests that nitric oxide (NO) induces a potent relaxation in the systemic vasculature. However, very few studies have examined the source from which NO is derived. Therefore, the present study used both anatomical and physiological approaches to establish whether NO-mediated vasodilation is via an endothelial or neural NO pathway in the large arteries of the estuarine crocodile Crocodylus porosus. Specific endothelial nitric oxide synthase (NOS) staining was observed in aortic endothelial cells following nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) histochemistry and endothelial NOS immunohistochemistry (IHC), suggesting that an endothelial NO pathway is involved in vascular control. This finding was supported by in vitro organ bath physiology, which demonstrated that the relaxation induced by acetylcholine (10-5 mol l-1) was abolished in the presence of the NOS inhibitor, N-omega-nitro-L-arginine (L-NNA; 10-4 mol l-1), the soluble guanylyl cyclase inhibitor, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ; 10-5 mol l-1), or when the endothelium was removed. Interestingly, evidence for a neural NO pathway was also identified in large arteries of the crocodile. Neural NOS was located in perivascular nerves of the major blood vessels following NADPH-d histochemistry and neural NOS IHC and in isolated aortic rings, L-NNA and ODQ, but not the removal of the endothelium, abolished the relaxation effect of the neural NOS agonist, nicotine (3x10-4 mol l-1). Thus, we conclude that the large arteries of C. porosus are potentially regulated by NO-derived from both endothelial and neural NOS.

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Significant variation in the egg and larval survival and juvenile recruitment of estuarine fishes has been linked to fluctuating environmental conditions. This present study compared the distribution and abundance of black bream (Acanthopagrus butcheri) eggs and yolk-sac larvae between two microtidal estuaries of different flow regimes, where the riverine flow into the Glenelg estuary was around eight times the flow volume into the Hopkins estuary. Samples were collected monthly from September to November at sites along each estuary where vertical profiles of temperature, salinity and dissolved oxygen (DO) were measured, and vertically stratified sampling of black bream eggs and yolk-sac larvae was conducted using a Schindler sampler. Salt wedge formation was apparent in both estuaries, with significant de-oxygenation of deeper, saline waters. Eggs occurred in a wide range of DO levels but yolk-sac larvae were less common at the lowest levels. Most eggs and yolk-sac larvae were collected in salinities greater than 10. Results suggested that egg mortality was higher in the Hopkins than the Glenelg estuary, which may be associated with the hypoxic conditions characteristic of low-flow conditions. The results have significant implications in terms of climate change that is predicted to lead to warmer, drier conditions in south-eastern Australia, potentially increasing stratification and subsequent hypoxic zones.

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In Western research, cruelty to animals in childhood has been associated with comorbid conduct problems and with interpersonal violence in later life. However, there is little understanding of the etiology of cruelty to animals, and what in the child's life may require attention if the chain linking animal cruelty and later violence is to be broken. The study reported in this paper investigated the association between parent-reported cruelty to animals, and parent- and self-reported psychological strengths and weaknesses in a sample of 379 elementary school children in an Eastern context, Malaysia. No gender differences were found in relation to cruelty to animals or psychological problems, as assessed with the Strengths and Difficulties Questionnaire (SDQ). However, there were different predictors of cruelty to animals for boys and girls. Regression analyses found that for boys, parent-reported hyperactivity was a unique predictor of Malicious and Total Cruelty to animals. For girls, self-reported conduct problems was a unique predictor of Typical Cruelty to animals. Parent-reported total difficulties were associated with Typical, Malicious, and Total Cruelty to animals. We suggest that routine screening of children with an instrument such as the SDQ may help to detect those children who may need to undergo further assessment and perhaps intervention to break the chain linking childhood cruelty to animals and later conduct problems.

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When older people enter residential care facilities, disruption to social networks may occur, with detrimental effects on health and wellbeing. This article reports on a study undertaken in an aged care facility in Melbourne, Australia, that explored the potential for a visiting companion animal programme to improve the health and wellbeing of residents and to promote their capacity for building relationships. Results back assertions in the literature that companion animals foster relationships by giving people opportunities to interact with others, but further study is needed to verify the link

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Childhood cruelty to animals is a symptom of conduct disorder that has been linked to the perpetration of violence in later life. Research has identified several factors associated with its etiology, including social factors. However, no cross-cultural studies on this phenomenon have been reported. This study investigated childhood cruelty to animals in Japan, Australia and Malaysia. Parents of 1,358 children between the ages of 5 and 13 years completed the Children’s Attitudes and Behaviours towards Animals questionnaire (CABTA) which assesses Typical and Malicious Cruelty to animals. Analyses revealed no overall differences between children from these countries on either scale. However, younger boys were more likely to be cruel than younger girls in each country, and younger children in Australia and Japan were more likely to be cruel that older children in those countries. The findings are discussed in relation to previous research, and recommendations for future studies are suggested.

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Maximum life span differences among animal species exceed life span variation achieved by experimental manipulation by orders of magnitude. The differences in the characteristic maximum life span of species was initially proposed to be due to variation in mass-specific rate of metabolism. This is called the rate-of-living theory of aging and lies at the base of the oxidative-stress theory of aging, currently the most generally accepted explanation of aging. However, the rate-of-living theory of aging while helpful is not completely adequate in explaining the maximum life span. Recently, it has been discovered that the fatty acid composition of cell membranes varies systematically between species, and this underlies the variation in their metabolic rate. When combined with the fact that 1) the products of lipid peroxidation are powerful reactive molecular species, and 2) that fatty acids differ dramatically in their susceptibility to peroxidation, membrane fatty acid composition provides a mechanistic explanation of the variation in maximum life span among animal species. When the connection between metabolic rate and life span was first proposed a century ago, it was not known that membrane composition varies between species. Many of the exceptions to the rate-of-living theory appear explicable when the particular membrane fatty acid composition is considered for each case. Here we review the links between metabolic rate and maximum life span of mammals and birds as well as the linking role of membrane fatty acid composition in determining the maximum life span. The more limited information for ectothermic animals and treatments that extend life span (e.g., caloric restriction) are also reviewed.

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There has been growing interest in linking the learning of Science with the literacies of Science and representations. Recent attention has been focused on learning theories that emphasise the socio-cultural and situated aspects of learning, and in particular the notion of learning as participation in a discourse community. This paper will describe a learning sequence planned wilh Year 5/6 teachers to study invertebrates in the schoolground environment, but with an additional focus in which students generated and negotiated representations, and discussed the adequacy of these. The paper will present data from video capture of classroom activities, students' work samples, and pre- and post-unit testing, to explore what a representational focus might entail in teaching science, and the role of representations in learning, reasoning and exploring in science.