966,740 research outputs found
Cover of the Diggers & diggings of Victoria as they are in 1855 [picture] /
No full textCondition: Stains and tears around the edges.; "The diggers & diggings of Victoria as they are in 1855 ; drawn on stone by S.T. Gill. Published by James J. Blundell & Co, 44 Collins St. Melbourne ; Campbell & Fergusson, Litho." -- printed on cover.; Also available in an electronic version via the Internet at: http://nla.gov.au/nla.pic-an6016192-1
Specimen of the Joanna type designed by Eric Gill, cut and cast at the Caslon letter foundry.
No full textOriginally issued as insert in The Book-collector's quarterly, December 193
Gill disease in barramundi (Lates calcarifer)
No full textDisease is a major impediment to world aquaculture, amplified by the increase of the intensity of aquaculture relieving pressure from over depleted wild stocks, but with intensity brings disease and particularly disease of the fragile gill organ, exposed directly to the water environment. There is little literature on barramundi biology and the various forms of culture impacting on health, particularly the gill and much research is required in gaining a further understanding of this popular eating fish.
The light microscope is a pivotal tool with cytology and histology mandatory in assessing gill health. The gill biopsy should be considered part of a clinical examination as the water medium surrounding the gill and on the gill contains often fragile organisms that would otherwise be lost in fixation for histology alone, but easily viewed with cytology. Barramundi are easily anaesthetised and recovered like many terrestrials and gill re-growth is rapid, healing within days. Biopsies should be viewed unstained with and without phase contrast and then stained and reviewed, recognizing some ectoparasites maybe lost with anaesthetic agents and stains. The sacrificing of the fish after a live gill biopsy is necessary with histology and microbiology our major tools for diagnostics, with no other non invasive methods readily available as for terrestrials. Every year many new water organisms related to aquaculture are described in the literature and the finding of novel and new organisms makes the veterinary examination of the live fish exciting yet imperative.
A major concern is the gill pathogens found in wild barramundi were similar to those found in culture. For example the prevalence of the parasite Henneguya a Myxosporidean was 90% in sea cages 60 km offshore from Darwin in the Bathurst Island river system and 66% for ponded fish with water drawn from the Darwin Elizabeth river, compared to 33% infected in the wild habitat of the Mary river system close to Darwin by road. However the bacterial disease Epitheliocystis had a prevalence of 66% in the sea cages and 18% of similarly sized fish in the Mary river system, yet nil found in the pond farm, but in this case sample numbers were restricted. Consequently the surveillance for new fish pathogens and monitoring for existing pathogens in the wild ecosystems and aquaculture facilities is necessary and must include the macro and micro flora and fauna surrounding such facilities as they are potentially affected from aquaculture waste streams. The sustainability of aquaculture in open water culture must be considered with great concern for many reasons, but disease by its nature could overwhelm a species and other aquatic life quickly disseminated in a dynamic water medium.
Freshwater culture of barramundi has problems with off flavour and disease, particularly recirculating aquaculture systems due to undercapitalization and possibly at this stage with existing type farms not suited for the culture of barramundi with one farm having all fish sampled diagnosed with systemic bacteraemia and gill Epitheliocystis. Commonly fish sampled from freshwater culture had suffered pathological changes to the gill, particularly hyperplasia indicating the fish are continually affected by issues of water quality and disease.
Pond culture appeared to control gill disease issues by affording lower stocking rates, high water exchanges from a river within metres, fallow and the flavour of the fish similar to wild catch or sea cage culture, when purged in brackish water. The decreased environmental and ecosystem risks, coupled with the pond farmer reporting good profits with a simple form of culture, also suitable for intensification is a success story for barramundi production for today and the future
[Cover for Victoria gold diggings and diggers as they are. Part 2] [picture] /
No full textExhibited: 34zBAustralian Sketchbook: Colonial Art and the art of S.T. Gill34yB, State Library of Victoria – 17 July – 18 October 2015; Exhibited: Gold and Civilisation, National Museum of Australia, Canberra, March - June 2001.; S130 pink paper, with ms. inscription bot. c. "by Stephen [sic] Thomas Gill"; S165 green paper
A novel computerized real effort task based on sliders
No full textIn this note, we present a novel computerized real effort task based on moving sliders across a screen which overcomes many of the drawbacks of existing real effort tasks. The task was first developed and used by us in Gill and Prowse (forthcoming). We outline the design of our \slider task", describe its advantages compared to existing real effort tasks and provide a statistical analysis of the behavior of subjects undertaking the task. We believe that the task will prove valuable to researchers in designing future real effort experiments, and to this end we provide z-Tree code and guidance to assist researchers wishing to implement the slider task
Sketches of the Victoria gold diggings and diggers as they are, 1852 Part 2 [picture] /
No full textTitle devised by cataloguer based on title pages.; Part of the Victoria gold diggings and diggers as they are, 1852; Inscriptions: "Part the second, containing 24 and completing a series of fortyeight sketches of the Victoria Gold Diggings and Diggers as they are by S.T.G., Stephen Thomas Gill., Lithographed & published by Macartney & Galbraith 30 Collins Street Melbourne"--Title page; "by Stephen Thomas Gill"--Printed below image.; Condition: Binding loose.; Selected items also available in electronic version via the Internet at: http://nla.gov.au/nla.pic-vn4555613
Nile Tilapia (Oreochromis niloticus) Gill Powder as a Novel Feed Additive for Enhanced Histological Structure and Performance in Broilers
No full textThe burgeoning population of Indonesia has led to a heightened demand for animal protein, particularly within the broiler industry. However, the commercial broiler feed tends to be costly due to its reliance on imported ingredients. Therefore, the potential utilization of Nile tilapia gills as an additional protein source for broiler feed has been explored in this study. The primary objective was to investigate how tilapia gill powder affects the histological structure of the small intestine, pectoralis muscle, and overall growth performance of broilers. For the study, a total of 200 dayold male Cobb-500 broiler chicks were utilized, employing a completely randomized design with five treatments and five replications. Each replication consisted of 8-day-old chicks. Tilapia gill powder was incorporated into the basal feed at varying concentrations: Control (basal feed), tilapia gill powder 1 (0.25% tilapia gill powder/kg basal feed), tilapia gill powder 2 (0.5% tilapia gill powder/kg basal feed), tilapia gill powder 3 (1% tilapia gill powder/kg basal feed), and tilapia gill powder 4 (2% tilapia gill powder/kg basal feed). Comprehensive histological analysis and growth performance assessments were carried out. The outcomes revealed that the tilapia gill powder 4 group, administered at an optimal concentration of 2% tilapia gill powder/kg basal feed, exhibited significant enhancements in small intestine morphology, pectoralis muscle structure, and overall chicken growth performance when compared to the control group. The supplementation of tilapia gill powder at this optimal concentration (2% tilapia gill powder/ kg basal feed) showcased a favorable impact on broiler performance
Gill disease surveillance
No full textGill disease affects fresh and marine aquaculture worldwide. In marine cultured Atlantic salmon, gill disease has been established as one of the most significant health challenges in the last decade. Amoebic gill disease (AGD) caused by the amoeba Neoparamoeba perurans is the most established, easiest recognized and only treatable type of marine gill disease. Other types are parasitic gill disease, viral gill disease, bacterial gill disease, zooplankton-associated gill disease (caused often by cnidarian nematocysts), harmful algal gill disease and chemical/toxin-associated gill disease. Especially zooplankton-associated gill disease in particular has caused severe mortality in Scottish salmon aquaculture in 2022 and 2023. When principal pathological changes in the gill are non-specific, either in combination with, or in the absence of, one or more of the seven distinctive types of gill disease (including AGD), the type of gill disease is referred to as complex gill disease (CGD). This talk uses surveillance for AGD and CGD as an example to discuss surveillance of gill disease for specific and non-specific conditions. Disease surveillance consists of many components. Diagnostic test evaluation and sample size calculations ensure accuracy, reliability, and representativeness of collected data. Together with data collection, management, analysis, dissemination, information technology, and collaboration, they form a comprehensive framework that can enable effective disease monitoring and decision-making. A variety of diagnostic tests is used for surveillance of AGD and CGD. Common tests for AGD are gross gill scores, histopathology, molecular techniques, and immunofluorescence antibody tests. For CGD there are fewer options because the case definition includes a variety of infectious agents or no primary pathogens in the case of environmental insults. Commonly used tests are therefore less pathogen-specific gill scores and histopathology. These tests have different characteristics, including expense, whether the test is lethal, type of information they provide, level of expertise needed to carry out the test and test performance. Which of these test(s) to include in a surveillance strategy is a complex process, which often starts with understanding how well tests perform, i.e. determining diagnostic sensitivity and specificity. Reason is that a test with a poor performance may result in numerous false positives and negatives – thereby confusing interpretation of results, and potentially leading to suboptimal mitigation strategies which can turn out to be very costly in the long term. Gross gill scores are medium to good in designating truly diseased fish and excellent in designating non-diseased fish. These non-lethal tests for AGD and CGD are frequently, usually weekly, performed on all salmon sites in Scotland at the same time as mandatory lice counts to minimize discomfort to fish. The tests are quick and easily performed by lifting the operculum of a sedated fish and visually observing all 8 gill arches, then giving one score between zero and five for the entire fish based on a standardized scoring criterion. Because of these characteristics, gross gill scores are a valuable tool for general field surveillance, and that can be augmented by other tests when there is a need for more information or increased test performance. Histopathology is a lethal test that requires a high level of technical expertise that is often not available in-house by salmon producers and therefore outsourced to diagnostic companies. Histopathology is often considered the gold standard (reference standard) for any type of gill disease because it is accurate and provides an understanding of the state of the fish. For example, if lesions are focal or diffuse, whether there is an acute inflammation or a more chronic condition, and which type of pathogens may be involved. It is difficult to accurately estimate diagnostic sensitivity and specificity of histopathology, because in scientific studies usually the second gill arch on the right is used. This leads to missed abnormalities when they occur elsewhere, leading to false negatives. Molecular PCR tests are very valuable non-lethal tests that can be used when a specific pathogen is targeted, such as N. perurans in the case of AGD, but not when no specific pathogens are always involved, such as for CGD. Generally, it is important to develop understanding of diagnostic sensitivity and specificity of tests for test selection. However, these test characteristics can also be used to estimate true prevalences and predictive values, which can help enrich surveillance strategies. Another important component of surveillance is the sample size. Mostly it is much more convenient and economical to examine a sample of a population rather than conduct a census, therefore we sample a subset of a population. In a census, the only error is in the measurement itself; with samples, error can arise from both measurement and sampling error. By designing a well-planned sampling strategy, the information obtained can be almost as good as information obtained from a census, when the sample size is correct. In aquaculture, a sample size consideration is rarely as simple as “how many fish?”, because fish are grouped in pens and pens in sites, and individual fish characteristics within a pen are more similar to each other than those of fish in different pens. In addition, for gross gill scores, the variation between fish is not similar at all levels of gill scores; at higher gill scores there is more variability compared to that at lower gill scores. Using intra-correlation coefficients, we developed a decision support tool that considers the variance-covariance components so that sample sizes can be estimated that take the structure of the system into account (https://epidemiology.sruc.ac.uk/shiny/apps/gillhealth/). Evidence based sample size calculators, such as the one described, are not meant to be used on a day-to-day basis but are designed to assist when a sampling protocol is developed, or an existing protocol reviewed. They ensure that a representative and statistically meaningful amount of data is collected, increase the precision of estimates, and reduce the likelihood of errors and biases. This ensures that the surveillance findings are robust. They also help optimize resource allocation because they enable cost-effective data collection, while minimizing wastage of resources.Other essential components of surveillance include data collection methods, data management pipelines, analysis, and dissemination. Data collection methods must be standardized and consistent to ensure data quality. This is often challenging in the context of salmon aquaculture because companies own multiple farms and thus time and effort is required to ensure consistency between personnel at different locations. Online reoccurring courses can help improve standardization. Data management involves secure storage, timely entry, and rigorous quality control. Analysis of collected data helps identify trends and potential outbreaks, supporting decision-making. When such analysis includes multiple producers, it is crucial to consider case definitions and ensure that models include structure, e.g. through random effect components, so that between-company variability is considered. Finally, sharing surveillance findings with relevant authorities and the public helps dissemination, and promotes transparency and awareness where deemed appropriate.<br/
Victoria gold diggings and diggers as they are, August 1852 Part 1 [picture] /
No full textTitle devised by cataloguer based on title pages.; Part of the Victoria gold diggings and diggers as they are, 1852; Inscriptions: "Part the first, containing 24 sketches of the Victoria Gold Diggings and Diggers as they are by S.T.G., Stephen Thomas Gill., Lithographed & published by Macartney & Galbraith 30 Collins Street Melbourne August 1852"--Title page.; Condition: Binding loose
Gill disease surveillance
No full textGill disease affects fresh and marine aquaculture worldwide. In marine cultured Atlantic salmon, gill disease has been established as one of the most significant health challenges in the last decade. Amoebic gill disease (AGD) caused by the amoeba Neoparamoeba perurans is the most established, easiest recognized and only treatable type of marine gill disease. Other types are parasitic gill disease, viral gill disease, bacterial gill disease, zooplankton-associated gill disease (caused often by cnidarian nematocysts), harmful algal gill disease and chemical/toxin-associated gill disease. Especially zooplankton-associated gill disease in particular has caused severe mortality in Scottish salmon aquaculture in 2022 and 2023. When principal pathological changes in the gill are non-specific, either in combination with, or in the absence of, one or more of the seven distinctive types of gill disease (including AGD), the type of gill disease is referred to as complex gill disease (CGD). This talk uses surveillance for AGD and CGD as an example to discuss surveillance of gill disease for specific and non-specific conditions. Disease surveillance consists of many components. Diagnostic test evaluation and sample size calculations ensure accuracy, reliability, and representativeness of collected data. Together with data collection, management, analysis, dissemination, information technology, and collaboration, they form a comprehensive framework that can enable effective disease monitoring and decision-making. A variety of diagnostic tests is used for surveillance of AGD and CGD. Common tests for AGD are gross gill scores, histopathology, molecular techniques, and immunofluorescence antibody tests. For CGD there are fewer options because the case definition includes a variety of infectious agents or no primary pathogens in the case of environmental insults. Commonly used tests are therefore less pathogen-specific gill scores and histopathology. These tests have different characteristics, including expense, whether the test is lethal, type of information they provide, level of expertise needed to carry out the test and test performance. Which of these test(s) to include in a surveillance strategy is a complex process, which often starts with understanding how well tests perform, i.e. determining diagnostic sensitivity and specificity. Reason is that a test with a poor performance may result in numerous false positives and negatives – thereby confusing interpretation of results, and potentially leading to suboptimal mitigation strategies which can turn out to be very costly in the long term. Gross gill scores are medium to good in designating truly diseased fish and excellent in designating non-diseased fish. These non-lethal tests for AGD and CGD are frequently, usually weekly, performed on all salmon sites in Scotland at the same time as mandatory lice counts to minimize discomfort to fish. The tests are quick and easily performed by lifting the operculum of a sedated fish and visually observing all 8 gill arches, then giving one score between zero and five for the entire fish based on a standardized scoring criterion. Because of these characteristics, gross gill scores are a valuable tool for general field surveillance, and that can be augmented by other tests when there is a need for more information or increased test performance. Histopathology is a lethal test that requires a high level of technical expertise that is often not available in-house by salmon producers and therefore outsourced to diagnostic companies. Histopathology is often considered the gold standard (reference standard) for any type of gill disease because it is accurate and provides an understanding of the state of the fish. For example, if lesions are focal or diffuse, whether there is an acute inflammation or a more chronic condition, and which type of pathogens may be involved. It is difficult to accurately estimate diagnostic sensitivity and specificity of histopathology, because in scientific studies usually the second gill arch on the right is used. This leads to missed abnormalities when they occur elsewhere, leading to false negatives. Molecular PCR tests are very valuable non-lethal tests that can be used when a specific pathogen is targeted, such as N. perurans in the case of AGD, but not when no specific pathogens are always involved, such as for CGD. Generally, it is important to develop understanding of diagnostic sensitivity and specificity of tests for test selection. However, these test characteristics can also be used to estimate true prevalences and predictive values, which can help enrich surveillance strategies. Another important component of surveillance is the sample size. Mostly it is much more convenient and economical to examine a sample of a population rather than conduct a census, therefore we sample a subset of a population. In a census, the only error is in the measurement itself; with samples, error can arise from both measurement and sampling error. By designing a well-planned sampling strategy, the information obtained can be almost as good as information obtained from a census, when the sample size is correct. In aquaculture, a sample size consideration is rarely as simple as “how many fish?”, because fish are grouped in pens and pens in sites, and individual fish characteristics within a pen are more similar to each other than those of fish in different pens. In addition, for gross gill scores, the variation between fish is not similar at all levels of gill scores; at higher gill scores there is more variability compared to that at lower gill scores. Using intra-correlation coefficients, we developed a decision support tool that considers the variance-covariance components so that sample sizes can be estimated that take the structure of the system into account (https://epidemiology.sruc.ac.uk/shiny/apps/gillhealth/). Evidence based sample size calculators, such as the one described, are not meant to be used on a day-to-day basis but are designed to assist when a sampling protocol is developed, or an existing protocol reviewed. They ensure that a representative and statistically meaningful amount of data is collected, increase the precision of estimates, and reduce the likelihood of errors and biases. This ensures that the surveillance findings are robust. They also help optimize resource allocation because they enable cost-effective data collection, while minimizing wastage of resources.Other essential components of surveillance include data collection methods, data management pipelines, analysis, and dissemination. Data collection methods must be standardized and consistent to ensure data quality. This is often challenging in the context of salmon aquaculture because companies own multiple farms and thus time and effort is required to ensure consistency between personnel at different locations. Online reoccurring courses can help improve standardization. Data management involves secure storage, timely entry, and rigorous quality control. Analysis of collected data helps identify trends and potential outbreaks, supporting decision-making. When such analysis includes multiple producers, it is crucial to consider case definitions and ensure that models include structure, e.g. through random effect components, so that between-company variability is considered. Finally, sharing surveillance findings with relevant authorities and the public helps dissemination, and promotes transparency and awareness where deemed appropriate.<br/
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