7 resultados para Brycon cephalus (Gunther)

em Deakin Research Online - Australia


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Fish transport is one of the most stressful procedures in aquaculture facilities. The present work evaluated the stress response of matrinxã to transportation procedures, and the use of clove oil as an alternative to reduce the stress response to transport in matrinxã (Brycon cephalus). Clove oil solutions were tested in concentrations of 0, 1, 5 and 10 mg/L during matrinxã transportation in plastic bags, supplied with water and oxygen as the usual field procedures in Brazil. Clove oil reduced some of the physiological stress responses (plasma cortisol, glucose and ions) that we measured. The high energetic cost to matrinxã cope with the transport stress was clear by the decrease of liver glycogen after transport. Our results suggest that clove oil (5 mg/l) can mitigate the stress response in matrinxã subjected to transport.

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The present work evaluated several aspects of the generalized stress response [endocrine (cortisol), metabolic (glucose), hematologic (hematocrit and hemoglobin) and cellular (HSP70)] in the Amazonian warm-water fish matrinxã (Brycon amazonicus ) subjected to an acute cold shock. This species farming has been done in South America, and growth and feed conversion rates have been interesting. However, in subtropical areas of Brazil, where the water temperature can rapidly change, high rates of matrinxã mortality have been associated with abrupt decrease in the water temperature. Thus, we subjected matrinxã to a sudden cold shock by transferring the fish directly to tanks in which the water temperature was 10oC below the initial conditions (cold shock from 28ºC to 18oC). After 1h the fish were returned to the original tanks (28ºC). The handling associated with tank transfer was also imposed on control groups (not exposed to cold shock). While exposure to cold shock did not alter the measured physiological conditions within 1h, fish returned to the ambient condition (water at 28º C) significantly increased plasma cortisol and glucose levels. Exposure to cold shock and return to the warm water did not affect HSP70 levels. The increased plasma cortisol and glucose levels after returning the fish to warm water suggest that matrinxã requires cortisol and glucose for adaptation to increased temperature.

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Labour markets, like all market institutions, exhibit structural and dynamic characteristics. Both the structural and dynamic characteristics of labour markets inevitably change and evolve over time in response to a host of exogenous and endogenous factors. In the case of the Australian labour market, structural changes are reflected in significant shifts in the industry and occupational composition of employment, the decline of full-time work and the concomitant rise in part-time and atypical forms of employment, demographic changes in the labour force, as well as changes in social and individual preferences. Dynamic shifts can be found in cyclical pattern of employment and wages growth, the growth in labour mobility, and transitions between various labour market states.
The starting point for this paper is that these structural and dynamic changes have given rise to an increase in the likelihood that individuals will experience a transition between various labour market states, and a greater diversity in the range of transitions they may experience over their working life. This acceleration in the rate of transition generates ‘transition costs’ for both employers and employees, as well the likelihood of mismatch between employer and employee working time preferences. As a consequence, existing labour market policy regimes, based on the traditional model of labour market participation over the life course may not provide adequate protection for most workers today.
Gunther Schmid (1998) and others have proposed institutional reforms which promote ‘transitional labour markets’. Transitional labour market institutions are those that allow individuals (and firms) to successfully adjust to critical events. While transitional labour market institutions may consist of traditional ‘active labour market policy’ mechanisms, Schmid and others have proposed a range of innovative policy responses which allow individuals (and firms) to adjust the intensity of their abour market participation over the life cycle. In this paper we use the general approach of advocated by the transitional labour market concept to do three things. First, we investigate the processes by which the nature of labour market transitions has changed over time. Second, we review the range of policy options available to government to smooth labour market dysfunctions associated with labour market transitions, with the objective of ensuring labour markets operate more efficiently and more equitably. Third, we focus on one possible way in which an existing labour market institution, Long Service Leave (LSL), could be reformed to make way for a more comprehensive transitional labour market institution in the form of a ‘working time bank’.

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The so-called "literary debate" in Greek, Latin and many Near Eastern
languages is a well-developed genre. In his 1987 article, Geert Jan van Gelder surveyed its background more than adequately, 1 and very few details of that paper need to be repeated here. He assessed thoroughly the historical contribution of numerous poets to the relationship between "the sword and the pen," and also analyzed various aspects of this relationship in a few prose texts.

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Plasmodium falciparum causes the virulent form of malaria and disease manifestations are linked to growth inside infected erythrocytes. To survive and evade host responses the parasite remodels the erythrocyte by exporting several hundred effector proteins beyond the surrounding parasitophorous vacuole membrane. A feature of exported proteins is a pentameric motif (RxLxE/Q/D) that is a substrate for an unknown protease. Here we show that the protein responsible for cleavage of this motif is plasmepsin V (PMV), an aspartic acid protease located in the endoplasmic reticulum. PMV cleavage reveals the export signal (xE/Q/D) at the amino terminus of cargo proteins. Expression of an identical mature protein with xQ at the N terminus generated by signal peptidase was not exported, demonstrating that PMV activity is essential and linked with other key export events. Identification of the protease responsible for export into erythrocytes provides a novel target for therapeutic intervention against this devastating disease.